Biomarkers of effect as determined in human biomonitoring studies on hexavalent chromium and cadmium in the period 2008–2020

Environmental Research 197 (2021) 110998 Available online 11 March 2021 0013-9351/© 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Review article Biomarkers of effect as determined in human biomonitoring studies on hexavalent chromium and cadmium in the period 2008–2020 C´ elia Ventura a , Bruno Costa Gomes a , Axel Oberemm b , Henriqueta Louro a , Pasi Huuskonen c , Vicente Mustieles d , e , f , Mariana F. Fern´ andez d , e , f , Sophie Ndaw g , Marcel Mengelers h , Mirjam Luijten i , Claudia Gundacker j , * , 1 , Maria Jo˜ ao Silva a , ** , 1 a National Institute of Health Doutor Ricardo Jorge (INSA), Human Genetics Department, Av. Padre Cruz, 1649-016, Lisbon, Toxicogenomics and Human Health (ToxOmics), NOVA Medical School/FCM, Universidade Nova de Lisboa, Portugal b German Federal Institute for Risk Assessment, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany c Finnish Institute of Occupational Health, PO Box 40, FI-00032 Ty¨ oterveyslaitos, Finland d Center for Biomedical Research (CIBM), University of Granada, Granada, Spain e Biosanitary Research Institute of Granada (ibs.GRANADA), Granada, Spain f Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Spain g French National Research and Safety Institute (INRS), France h National Institute for Public Health and the Environment (RIVM), Centre for Nutrition, Prevention and Health Services, Department of Food Safety, Bilthoven, the Netherlands i National Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, the Netherlands j Institute of Medical Genetics, Medical University of Vienna, Waehringer Strasse 10, A-1090 Vienna, Austria ARTICLE INFO Keywords: Toxic metals Cancer Oxidative stress Nephrotoxicity Immunotoxicity Mode of action Adverse outcome pathway (AOP) ABSTRACT A number of human biomonitoring (HBM) studies have presented data on exposure to hexavalent chromium [Cr (VI)] and cadmium (Cd), but comparatively few include results on effect biomarkers. The latter are needed to identify associations between exposure and adverse outcomes (AOs) in order to assess public health implications. To support improved derivation of EU regulation and policy making, it is of great importance to identify the most reliable effect biomarkers for these heavy metals that can be used in HBM studies. In the framework of the Human Biomonitoring for Europe (HBM4EU) initiative, our study aim was to identify effect biomarkers linking Cr(VI) and Cd exposure to selected AOs including cancer, immunotoxicity, oxidative stress, and omics/epigenetics. A comprehensive PubMed search identified recent HBM studies, in which effect biomarkers were examined. Validity and applicability of the markers in HBM studies are discussed. The most frequently analysed effect biomarkers regarding Cr(VI) exposure and its association with cancer were those indicating oxidative stress (e.g., 8-hydroxy-2’-deoxyguanosine (8-OHdG), malondialdehyde (MDA), glutathione (GSH)) and DNA or chromosomal damage (comet and micronucleus assays). With respect to Cd and to some extent Cr, β-2-microglobulin (B2-MG) and N-acetyl-β-D-glucosaminidase (NAG) are well-established, sensitive, and the most common effect biomarkers to relate Cd or Cr exposure to renal tubular dysfunction. Neutrophil gelatinase-associated lipocalin Abbreviations: 8-OHdG, 8-hydroxy-2’-deoxyguanosine; 8-isoPGF2 α , 8-isoprostaglandin-F2 α ; α 1-MG, α 1-microglobulin; AKI, Acute Kidney Injury; AO, Adverse Outcome; AOP, Adverse Outcome Pathway; B2-MG, β-2 MicroGlobulin; CAT, catalase; CC-16, Clara Cell protein; CCL5, C-C motif chemokine ligand 5; CKD, Chronic Kidney Disease; Cr(VI), hexavalent chromium; CRP, C-reactive protein; Cys-C, Cystatin C; DPD, deoxypyridinoline; GPx, Glutathione Peroxidase; GR, glucocorticoid receptor; GR, glutathione reductase; GFR, Glomerular Filtration Rate; GSH, glutathione; HBM, Human BioMonitoring; HNE-MA, 4-hydroxy-2-nonenal-mercapturic acid; IARC, International Agency for Research on Cancer; IFNα , Interferon-alpha; IL, InterLeukin; KE, Key-Event; KDa, kiloDalton; KIM, Kidney Injury Molecule; LFABP, Liver-type Fatty Acid Protein; LPO, Lipid Peroxidation; MDA, Malondialdehyde; MeSH, Medical Subject Headings; MIE, Molecular Initiating Event; MoA, Mode of Action; MT, Metallothionein; NAG, N-Acetyl-β-D-Glucosaminidase; NGAL, Neutrophil Gelatinase-Associated Lipocalin; OGG1, 8-Oxoguanine DNA Glycosylase; PAH, Polycyclic Aromatic Hydrocarbon; PBA, polyclonal B Cell Activation; PBMC, peripheral blood mononucleate cells; PCR, Polymerase Chain Reaction; PGE2, Prostaglandin E2; ROS, Reactive Oxygen Species; SP-D, surfactant-associated protein D; SOD, Superoxide Dismutase; TCR, T-cell receptor; TNFα , Tumor Necrosis Factor-alpha; TAC, Total antioxidant capacity. * Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (C. Gundacker), [email protected] (M.J. Silva). 1 Shared authorship. Contents lists available at ScienceDirect Environmental Research journal homepage: www.elsevier.com/locate/envres https://doi.org/10.1016/j.envres.2021.110998 Received 29 December 2020; Received in revised form 5 March 2021; Accepted 5 March 2021 Environmental Research 197 (2021) 110998 2 (NGAL) and kidney injury molecule (KIM)-1 could serve as sensitive biomarkers of acute kidney injury in response to both metals, but need further investigation in HBM studies. Omics-based biomarkers, i.e., changes in the (epi-)genome, transcriptome, proteome, and metabolome associated with Cr and/or Cd exposure, are promising effect biomarkers, but more HBM data are needed to confirm their significance. The combination of established effect markers and omics biomarkers may represent the strongest approach, especially if based on knowledge of mechanistic principles. To this aim, also mechanistic data were collected to provide guidance on the use of more sensitive and specific effect biomarkers. This also led to the identification of knowledge gaps relevant to the direction of future research. 1. Introduction Human biomonitoring (HBM) assesses human exposure to chemicals and pollutants by analysing these substances, their metabolites or reaction products in blood, urine, saliva, placenta, breast milk, faeces, hair and nails. Regarding metal and metalloid species, blood, urine and hair are the most widely accepted biological matrices to measure their cumulative body burden (CDC, 2005; Gil and Hern´ andez, 2015). HBM allows for taking into account lifestyle factors and individual susceptibilities, which helps to identify subpopulations at risk. Additionally, it enables the identification of spatial and temporal trends in exposure and to detect exposure-health relationships. HBM is also a valuable tool for the detection of emerging pollutants. The evidence gathered through HBM can contribute to human health risk assessment of chemicals (Louro et al., 2019), to priority setting of actions and measures for policy-making, to assessing the effectiveness of implemented environment and health policies in reducing exposure to hazardous substances, and to evaluating more comprehensively the impact of policy measures on human health (Joas et al., 2012; Ganzleben et al., 2017). The Human Biomonitoring Initiative for Europe (HBM4EU, www. hbm4eu.eu), involving 30 European countries, the European Environment Agency (EEA) and the European Commission, surveys the actual exposure of citizens to chemicals and environmental pollutants, in order to support policy-making and to minimize adverse health outcomes. The heavy metals hexavalent chromium [Cr(VI)] and cadmium (Cd), classified by the International Agency for Research on Cancer (IARC) as group 1 carcinogens (IARC 2012), are included as priority substances within HBM4EU. Cd is a naturally occurring heavy metal, which is present in small quantities in the environment. Human activities over the last 120 years have significantly increased Cd emissions (WHO 2019; ATSDR 2012). In addition, tobacco and food are the most important sources of exposure of the general population (EFSA 2009; Bocca et al., 2020). Cd is stored in kidney and liver with a biological half-life of 10–30 years (J¨ arup and Åkesson 2009). Cd is primarily toxic to the kidney. Prolonged or high exposure to Cd may result in a reduced glomerular filtration rate (GFR) and ultimately in renal failure. Prolonged urinary levels of >4 μ g Cd/g creatinine are associated with renal tubular dysfunction but can also cause bone demineralization in children (Nordberg 2009; Sughis et al., 2011). Cd exposure may also increase the risk of osteoporosis and fracture in pregnant and postmenopausal women and the elderly as well as an increased risk of lung, endometrial, bladder and breast cancer in the general population (EFSA 2009; Nordberg et al., 2015; Grioni et al., 2019). Whether human exposure at doses below 2.5 μ g/kg bw/week (equivalent to <1 μ g Cd/g creatinine in urine) affects skeletal, renal, hormonal or reproductive functions is controversial (Åkesson et al., 2014; Nordberg et al. 2015, 2018; Apostoli and Catalani 2015; Bernard 2016; Ronchetti et al., 2016). This lack of clarity, also with regard to occupationally exposed persons, is the main reason for including Cd as a priority substance in HBM4EU. Cr(VI), the second most stable oxidation state of chromium, is rarely found in nature. Environmental exposure occurs through tobacco smoke, including electronic cigarette smoke (Williams et al., 2017) and inhalation of polluted air or ingestion of contaminated water in citizens living in industrial or contaminated areas (IARC, 2012). Exposure to environmental Cr(VI) through the oral route has been associated to chronic kidney disease (Kulathunga et al., 2019; Tsai et al., 2017) and gastrointestinal disturbances, including stomach ulcers and oral cancer (Zhitkovich, 2011). Even though the meta-analysis conducted by Welling et al. (2015) pointed out that Cr(VI) was a stomach carcinogen for humans, a more recent systematic review and meta-analysis showed that Cr(VI) does not increase the incidence of stomach cancer (Suh et al., 2019). Nevertheless, anthropogenic activities such as welding, electroplating, surfaces treatment and leather tanning are by far the largest source of Cr(VI). Occupational exposure occurs in workers involved in such industrial activities, the main exposure routes being dermal contact and inhalation of dust and mist or fumes (Elhosary et al., 2014; Lin et al., 2019; Pan et al., 2018; Wang et al. 2011, 2012). Following inhalation, Cr (VI) reaches the respiratory tract and a high percentage of both solubilized Cr(VI) and poorly soluble Cr particles (<5 μ m) enter the bloodstream and is distributed to nearly all tissues (ATSDR, 2008). The main adverse health outcomes due to chronic Cr(VI) inhalation are lung impairment, including pneumonia, bronchitis, asthma and lung cancer (Al osman et al., 2019; Saha et al., 2011). Similarly to Cd, total Cr accumulates also in human kidney, besides liver and bone tissues (IARC 2012), increasing the risk of nephrotoxicity, among other undesirable effects. Despite its carcinogenic properties, the use of Cr(VI) compounds (chromates, chromium trioxide and dichromium tris(chromate)) for specific purposes is still authorized under the European regulation (EC, 1907/2006) concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), raising occupational health concerns that have been addressed under the HBM4EU project. Due to potential exposure sources, converging mechanisms of action or target organs, co-exposure to Cd and Cr(VI) has been the subject of research in recent years. One important objective of the HBM4EU project is to demonstrate the value and applicability of biomarkers of biological effect, further referred to as ‘effect biomarkers’, to complement biomarkers of exposure in HBM studies (Baken et al., 2019; Mustieles et al., 2020; Steffensen et al., 2020). Effect biomarkers are physiological parameters that mirror an exposure-related response that is associated with an altered biological structure, function, or with a disease phenotype (WHO, 1993; NRC, 2006). These include early biochemical, cellular or molecular effects (Corradi et al., 2015) that are measurable in target or surrogate tissues, e.g., blood cells, and that are associated with the adverse outcome (AO). Thus, mechanistic information about Cr(VI) or Cd Modes of Action (MoA) is of utmost importance to identify the most sensitive as well as robust effect biomarkers, i.e., those that measure alterations recognized as being central to the targeted health effect. The framework of the Adverse Outcome Pathway (AOP) is based on a series of linked key events (KEs) that begins with a molecular initiating event (MIE) and ends in an AO. The concept allows to evaluate the relevance of an effect biomarker to an expected AO (Leist et al., 2017; OECD 2013, 2018). Concerning the MoAs, Cr(VI) and Cd likely share KEs at the molecular and cellular levels, involving oxidative stress and changes in cell redox status, inhibition of DNA repair mechanisms and altered regulation of gene expression that can induce genetic instability and disturbances of cell homeostasis. In cells, Cr(VI) is reduced to Cr(III), a more thermodynamically stable form of Cr. The intermediate Cr C. Ventura et al. Environmental Research 197 (2021) 110998 3 species, i.e., Cr(IV) and Cr(V) are able to form DNA and DNA-protein adducts (e.g. DNA-amino acid cross-links) that may give rise to DNA singleand double-strand breaks (Stearns et al., 1995). During the intracellular detoxification process, reactive oxygen species (ROS) are also formed, which are considered to mediate Cr(VI)-induced changes in cell signalling and homeostasis leading to cell death by apoptosis (Chen et al., 2019a). ROS accumulation generates oxidative stress and contributes to chronic inflammation, metabolic reprogramming, and genetic instability, ultimately leading to tumor development (Wang et al., 2016; Chen et al., 2019b). The molecular toxicity of Cd also involves the (indirect) induction of ROS and the reduction of cellular antioxidants. In addition, the inhibition of DNA repair enzymes, the influence on gene transcription and translation, the disturbance of the ubiquitin-proteasome system and the calcium homeostasis are Fig. 1. Results of the literature survey on (A) effect biomarkers used in HBM studies related to Cr(VI) exposure or on (B) Cr(VI) exposure and cancer. C. Ventura et al. Environmental Research 197 (2021) 110998 4 recognized to mediate its toxicity. As a result, Cd can interfere with essential cellular processes such as proliferation, differentiation, and apoptosis, which may contribute to its carcinogenicity (Yu et al., 2008; EFSA 2009). To obtain an overview of the most informative effect biomarkers suitable for use in HBM studies on Cr(VI) and/or Cd exposed populations, a comprehensive literature search was carried out. The most promising biomarkers of effect are presented and discussed considering the mechanism of action and specific AOs for each heavy metal. 2. Methods A literature search in PubMed was conducted to identify studies published between 2008 and 2018 that included effect biomarkers associated with Cr or Cd exposures, supplemented by a targeted search for studies dealing with particular AOs. For Cr(VI), the focus was on cancer, stomach cancer, respiratory cancer and lung cancer (Fig. 1). The search for Cd focused on immunotoxicity, epigenetics/omics, and oxidative stress (Fig. 2). Initially, we did not address on nephrotoxicity, as effect biomarkers for this endpoint have already been widely described (e.g. EFSA 2009). Nevertheless, when searching for Cd and effect markers, we mainly found those effect markers indicating renal damage. As depicted in Figs. 1 and 2, numerous search terms and search term combinations were used, based on MeSH® terms and MeSH supplementary concepts (https://www.nlh.gov/mesh). The selection of abstracts, after exclusion of inappropriate studies (non-human studies, pure environmental studies, pure exposure studies, publications in non-English language, commentaries, studies for the development of methods and identification technologies), was subjected to a thorough review. With the aim to link the effect biomarkers identified in the search to KEs that ultimately lead to the AOs for Cr(VI) or Cd exposures, articles containing mechanistic information from animal studies or in vitro studies were also used (Fig. 1B). The studies found in the literature search formed the basis for the review. The selected references are listed in Table 1. Where indicated, we have added supplementary information from other reviews and original papers. An additional literature search was conducted in February 2021 for the period 2018–2020. These new articles are summarized in Suppl. Table 1 and their findings discussed when they add relevant information beyond that already found. 3. Results Among the articles retrieved were many studies on established effect biomarkers, which are summarized in Table 1. Their applicability, clinical significance, and mechanistic relevance associated with the respective health outcome are also included in the table. Other effect biomarkers identified for both metals whose utility remains to be confirmed in larger populations and/or other contexts are referred to as candidate biomarkers. The latter are mostly associated with omics approaches and are presented in Table 2 along with some foreseeable advantages and limitations in their use. The first search for effect biomarkers applied in HBM studies regarding Cr(VI) exposure resulted in 1041 articles, from which 50 were Fig. 2. Results of the literature survey on effect biomarkers used in HBM studies related to Cd exposure. C. Ventura et al. Environmental Research 197 (2021) 110998 5 Table 1 Effect biomarkers identified for Cr(VI) or Cd-exposed populations according to the respective literature sources (column ’References’) and their mechanistic relevance for the selected adverse health effect. The biomarkers are listed separately for Cr(VI) and Cd. Biomarker of effect Mechanistic relevance and link with health outcome References Cr(VI) Genotoxicity Chromosome alterations (Micronucleus or chromosome aberrations in peripheral blood lymphocytes or micronucleus in buccal cells) Cr(VI) induces DNA damage either mediated by reactive oxygen species (ROS) from its intracellular reduction, by interacting with proteins or with DNA (Wedrychowski et al., 1985; DeLoughery et al., 2015), or through interferences with DNA repair systems causing DNA singleand double-strand breaks (DSBs) (Christie et al., 1984; DeLoughery et al., 2015). Unrepaired or erroneously repaired DBS may give rise to structural chromosome anomalies, which can be experimentally assessed through chromosome aberrations or micronuclei (MN) in human peripheral lymphocytes (Albertini et al., 2000; Bonassi et al., 2007) or in buccal cells (for MN). The frequencies of chromosome aberration or micronucleated cells have been used as effect biomarkers in heavy metalsexposed populations (Annangi et al., 2016) and are known to be associated with cancer risk (Bonassi et al., 2007; Bofetta et al., 2007). Balachandar et al. (2010) Angelieri et al. (2011) Xiaohua et al. (2012) Sudha et al., (2011) a Li et al. (2014) Li et al. (2016) Yang et al. (2016) Wultsch et al., (2017) b Franken et al., (2017) a,c DNA damage (Comet assay in leukocytes or buccal cells; DNA-protein crosslinks) Different types of DNA damage have been identified following exposure to Cr(VI) and have been implicated in its genotoxicity both in vivo and in vitro: DNA strand breaks, inter-strand cross-links and DNA adducts. Using UvrABC nuclease and formamidopyrimidine glycosylase (Fpg), and ligation-mediated PCR methods, Arakawa et al. (2012) suggested that inside of the cells, Cr(VI) and Cr(V) interact with adenines and guanines of genomic DNA to cause bulky DNA adducts (e.g., GSH-Cr-DNA) and oxidative DNA damage, which are poorly repaired. Fang et al. (2014) showed the ability of Cr(VI) to intercalate between DNA basepairs (Fang et al., 2014). Unrepaired lesions can lead to mutation formation and, subsequently, to cancer development. The comet assay is one of the most used effect markers in human biomonitoring studies to measure DNA damage; its modification with the Fpg enzyme allows the additional detection of oxidative DNA damage. The information obtained can lead to individual advice on relative risks of genotoxic exposure to environmental or occupational stressors (Dusinska and Collins, 2008). Grass et al. (2010) d,e Balachandar et al. (2010) Sudha et al., (2011) a Zhang et al. (2011) Franken et al., (2017) c Mutation frequencies of T-cell receptor (TCR-Mf) Cr(VI) exposure induces directly and indirectly (via ROS) DNA lesions that, if unrepaired, may result in increased levels of mutations in somatic cells. The T-Cell Receptor (TCR) mutation assay measures the mutation frequencies of T-cell receptor in somatic cells and has been used in biomonitoring studies to predict the cancer risk following exposure to ionizing radiation (Taooka et al., 2006) or metal(loid)s (Coelho et al., 2013) exposure. Coelho et al., (2013) f Cr(VI) Oxidative stress 8-hydroxy-2’-deoxyguanosine (8-OHdG) r One of the major mechanisms that mediate Cr(IV)-induced cellular damage is ROS generation following binding of ROS scavengers (e.g., glutathione and ascorbate) to Cr(VI) and Cr(III) and their reduction to Cr(V) and Cr(IV). Free radicals such as the hydroxyl radicals are able to react with guanine residues and generate DNA adducts. Among these, 8-OHdG has been recognized as a relevant exposure and effect biomarker not only for oxidative damage associated with Cr(VI) exposure (and also Cd exposure; Huang et al., 2009) but with mutagenicity and cancer development (Valko et al., 2004; Chen et al., 2019 a, b). Measurement of urinary 8-OHdG can be carried out using high-performance liquid chromatography with tandem mass spectrometry (Pan et al., 2018) and other methods. Zhang et al. (2011) Ni et al., (2014) g Pizzino et al., (2014) h Pesh et al. (2015) Wang et al. (2015) Franken et al., (2017) c Savarino et al., (2017) i Pan et al. (2018) Lipid peroxidation (LPO) r Malondialdehyde (MDA) r MDA is the major product of polyunsaturated fatty acid peroxidation, a metabolic process of oxidative deterioration of lipids within the cell membrane that is catalysed by iron. This aldehyde is a highly toxic molecule that can react with DNA bases guanine, adenine, and cytosine to form premutagenic adducts (Jomova and Valco, 2011). It has been widely used as a biomarker of lipid peroxidation in epidemiological studies of Cr(VI) exposure. Khan et al. (2012) Serafim et al., (2012) j Ambreen et al. (2014) Zendehdel et al. (2015) Bibi et al. (2016) k Gube et al. (2010) Khan et al. (2012) Ambreen et al. (2014) Elhosary et al. (2014) Jamilian et al. (2016) Mozafari et al. (2016) Nascimento et al. (2017) Pan et al. (2018) Glutathione (GSH) r In the intracellular moiety Cr(VI) reacts with glutathione, which is a substrate for several enzymes that remove ROS and is also a powerful cellular antioxidant, giving rise to Cr(V). Likewise, Cr(VI) and then Cr(IV) become reduced to the next lower oxidation state by reacting with GSH while the latter become oxidized to glutathione disulfide (GSSG). In lung cells, ascorbate is the most important Cr(VI) reductant, although GSH also plays an important detoxification role. The risk of lung cancer increases when Cr(VI) doses overwhelm the cellular defence mechanisms (Jomova and Valco 2011). Low GSH concentrations and a high GSSG:GSH ratio have been measured in blood of patients with various diseases, including breast and lung cancer. The GSH system is also altered in lung inflammatory conditions and GSH concentrations in Khan et al. (2012) Ambreen et al. (2014) Bergamo et al., (2016) l (continued on next page) C. Ventura et al. Environmental Research 197 (2021) 110998 6 Table 1 (continued) Biomarker of effect Mechanistic relevance and link with health outcome References the epithelial lining fluid are decreased in idiopathic pulmonary fibrosis, asbestosis and acute respiratory distress syndrome (Comhair et al., 2002). Glutathione peroxidase (GPx) r Superoxide dismutase (SOD) r Enzymatic antioxidants can intercept, scavenge and neutralize ROS, and can reactivate intermediates generated in excess under physiological conditions. The most important antioxidant enzymes are SOD, catalase, and the glutathione redox system (glutathione peroxidase and glutathione-S-transferase) (Valko et al., 2007). The activity of selected antioxidant enzymes has been measured in blood samples as biomarkers of oxidative stress linked to Cr(VI) exposure. Bibi et al. (2016) k Khan et al. (2012) Ambreen et al. (2014) Prostaglandin E2 (PGE2) in exhaled breath condensate 8-iso-prostaglandin-F2 α (8-iso-PGF2 α ) in urine 8-iso-PGF2 α is an isoprostane (IsoPs) produced by the non-enzymatic peroxidation of arachidonic acid in membrane phospholipids. It has been considered as a reliable biomarker of lipid peroxidation. At present, measurement of F2-IsoPs in plasma or urine is regarded as one of the most reliable approaches for the assessment of oxidative stress status or free-radical–mediated lipid peroxidation in vivo and thereby it may be a reliable effect biomarkers for Cr(VI) (Dalle-Donne et al., 2006; Wang et al., 2015). Furthermore, 8-iso-PGF2 α is markedly increased, serving as a biomarker, in the bronchoalveolar lavage (BAL) fluid, plasma, urine, or exhaled breath condensate in several pulmonary diseases such as asthma, and interstitial lung disease, among others (Dalle-Donne et al., 2006). Grass et al., (2010) d Hoffmeyer et al., (2012) m Wang et al., (2015) n Thiol antioxidants Thiols are anti-oxidant molecules in the sulfhydryl group that can be found in plasma (albumin thiols, protein thiols and cysteine, cysteinylglycine, glutathione, homocysteine and γ-glutamylcysteine). Oxidation reaction of thiols with oxidizing molecules causes the formation of reversible disulphide bonds that can again be reduced to thiol groups. Dynamic thiol-disulphide homeostasis plays an important role in anti-oxidant defense, detoxification, and apoptosis, among others (Baba and Bhatnagar 2018). Serum and plasma levels of total thiol (SH groups) were lower in Cr(VI) exposed workers as compared to controls and correlated negatively with oxidative stress. Pournourmohammadi et al., (2008) o Elhosary et al. (2014) Zendehdel et al. (2015) Total antioxidant capacity (TAC) Several assays that determine the ability of a biological sample to reduce a substrate, for instance through hydrogen atom transfer or electron transfer reactions, as measuring the ability of serum to reduce Fe 3+ to Fe 2+ or Cu 2+ to Cu + . Serum levels of TAC were lower in cement industry workers as compared to controls. TAC was also lower in seminal plasma of males living in areas high polluted with toxic waste, but not in their blood. Cr supplements in women with polycystic ovary syndrome resulted in a significant elevation of plasma TAC. Pournourmohammadi et al., (2008) o Zendehdel et al. (2015) Jamilian et al. (2016) Nitrate and nitrite in exhaled breath condensate Production of nitric oxide (NO) is generally increased during inflammation and eventually is oxidated to nitrite (NO 2 ) and nitrate (NO 3 ), both of which are end-products of NO metabolism. Increased in welders. Gube et al. (2010) Brand et al. (2010) Cd Oxidative stress Glutathione peroxidase (GPx) r , glutathione (GSH) r , Selenium Cadmium is not a Fenton metal and therefore is unable to directly generate free radicals. However, some studies described indirect formation of ROS and RNS involving the superoxide radical, hydroxyl radical and nitric oxide. In rats exposed to Cd through drinking water significantly increased lipoperoxides, MDA and decreased activities of SOD and GPx were found in cardiac tissue (reviewed in Jomova and Valko 2011). Cabral et al. (2015) Protein carbonylation of GPx, glutathione reductase (GR), superoxide dismutase (SOD) r and catalase (CAT) Castillo-Castaneda (2017) Lipid peroxidation (e.g., MDA) r Castillo-Castaneda (2017) Cuypers et al. (2010) Cd Nephrotoxicity Urine β2-microglobulin (B2-MG) r B2-MG is a small protein of about 12 kDa necessary for cell surface expression of major histocompatibility factor (MHC) class I molecules and other (non-classical MHC-1) proteins such as hemochromatosis. It circulates in a soluble form in blood entirely reabsorbed by the nephron. Serum levels rise when glomerular filtration is impaired, while urinary levels increase when tubular reabsorption is harmed. Thus, urinary B2-MG may be a marker for glomerular rather than of tubular pathology (Grang´ e et al., 2016; Argyropoulos et al., 2017). B2-MG is recommended as marker of chronic kidney disease (CKD)(Foster et al., 2016; Tummalapalli et al., 2016). CKD lasts for at least 3 months and is often an irreversible defect (Kaufman et al., 2019). Cd concentrations in urine, when adjusted for creatinine, age, sex, and smoking are associated with B2-MG in ten studies retrieved by our search (see right column for references). Nordberg et al. (2009) Trzcinka-Ochocka et al. (2010) Ikeda et al. (2011) Swaddiwudhipong et al., (2012), 2015 Nishijo et al. (2014) Ke et al. (2015) Zhang et al. (2015) Wang et al. (2016) Eom et al. (2017) N-acetyl-β-D-glucosaminidase (NAG) r NAG is a large lysosomal brush border enzyme (>130 kDa) of the proximal tubular cells, stably present in urine. Plasma NAG cannot be filtered through the glomerular membrane and its increase in urine is exclusively caused by proximal tubular cell injury. NAG is defined as being more specific and sensitive to renal tubular injury than creatinine especially with its isoenzymes and when combined with other renal biomarkers, for example Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) (Çuhadar and Semerci 2016; Moriguchi et al., 2009; Argyropoulos et al., 2017). NAG is among the best characterized markers and proven to be a sensitive and robust indicator of acute kidney injury (AKI) (Ferguson et al., 2008). AKI is an abrupt increase in serum creatinine - generally over days - and is largely reversible (Kaufman et al., 2019). Cd concentrations in urine, when adjusted for creatinine, age, sex, smoking and other study-specific factors (e.g. concurrent Pb exposure), are associated with NAG in ten studies (see right column for references). Huang et al. (2009) Trzcinka-Ochocka et al. (2010) Boonprasert et al. (2011) Ikeda et al. (2011) Nordberg et al. (2009) Hambach et al. (2013) Nishijo et al. (2014) Zhang et al. (2015) Wang et al. (2016) Eom et al. (2017) Retinol binding protein (RBP) RBP is a low molecular weight protein belonging to the lipocalin super family. Its main function is to transport retinol (vitamin A). The majority of RBP-retinol circulates in the plasma bound to transthyretin, a complex that prevents its glomerular filtration. 4–5% of serum RBP- (continued on next page) C. Ventura et al. Environmental Research 197 (2021) 110998 7 Table 1 (continued) Biomarker of effect Mechanistic relevance and link with health outcome References retinol, however, circulates freely, pass the glomerular barrier and is then reabsorbed and degraded in the proximal tubule, a process mediated by megalin. Due to these properties, urinary RBP is an established biomarker of proximal tubular dysfunction and is used as a diagnostic tool in proximal tubulopathies (Domingos et al., 2016). Cd concentrations in urine, when adjusted for creatinine, age, sex, smoking and other study-specific factors (e.g. concurrent Pb exposure), are associated with RBP in three studies (see right column for references). Trzcinka-Ochocka et al. (2010) Hambach et al. (2013) Zhang et al. (2015) Glomerular filtration rate (GFR) GFR represents the flow of plasma from the glomerulus into Bowman’s space over a specified period. It is the main measure of kidney function calculated from blood creatinine and/or Cystatin-C (Cys-C) in conjunction with age, body size and gender. Combining serum creatinine and Cys-C are superior to equations using either Cys-C or serum creatinine alone (Wasung et al., 2015). Changes in GFR are used to define and diagnose several pathologies. In three studies Cd levels in urine are inversely correlated with GFR (Weaver et al., 2011; Swaddiwudhipong et al., 2012; Eom et al., 2017). Weaver et al. (2011) Swaddiwudhipong et al. (2012) Eom et al. (2017) Tsai et al. (2017) Wu et al. (2018) Urine albumin Urine albumin serves as a specific and stable biomarker for the early diagnosis of AKI. The combination of creatinine, Cystatin-C and urinary albumin to creatinine ratio enhances risk stratification for kidney disease progression and mortality (Wasung et al., 2015). Much higher levels of urinary albumin are observed with glomerular injury than with tubular injury. In rodents, albuminuria is a marker of cisplatin nephrotoxicity. Cisplatin increases albuminuria, but the clinical relevance is uncertain. The low costs of commercially available tests for the detection of urine albumin is an advantage for routine clinical use. Nonetheless, a panel of biomarkers would be necessary to identify the severity of injury and the type of insult (Bolisettyand Agarwal 2011; Griffin et al., 2019). Two studies found urinary Cd associated with urine albumin. Trzcinka-Ochocka et al. (2010) Nordberg et al. (2009) Urine total protein In one study, urinary total protein was associated with urine Cd levels (Swaddiwudhipong et al., 2012) Swaddiwudhipong et al., (2012), 2015 Urine α ₁₁-microglobulin (A1-MG) Urinary A1-MG offers a non-invasive, cost-effective diagnostic alternative for the early detection of tubular diseases caused by e.g. heavy metal intoxication. The 27-kDa glycoprotein, whose exact biological function is unknown, is found in various body fluids. Altered plasma/ serum levels are usually due to impaired liver or kidney function, but are also observed in clinical conditions such as HIV (Penders and Delanghe 2004). Ikeda et al. (2011) Cr(VI) Nephrotoxicity Kidney injury molecule-1 (KIM-1) KIM-1 is strongly upregulated in the proximal tubule cells after AKI. Its ectodomain is secreted into the lumen and serves as a urinary biomarker. KIM-1 also acts as a blood biomarker specifically reflecting AKI (Prozialeck and Edwards 2012; Sabbisetti et al., 2014). C´ ardenas-Gonz´ alez et al. (2016) p Cystatin C (Cys-C) Cys-C is a marker of the GFR. It is a low molecular weight protein and a potent cysteine protease inhibitor. The plasma concentration of Cystatin-C is proportional to glomerular filtration, making it ideal for GFR estimation. The protein has the ability to detect early renal failure as it provides a reliable GFR estimate at critical values. For this reason, Cys-C is regarded superior to serum creatinine. Also Cd increases the urinary excretion of Cys-C in rats (Prozialeck et al., 2016). Wang et al. (2011) Urine β2-microglobulin (B2-MG) r See information related to Cd nephrotoxicity Wang et al. (2011) Li et al. (2015)C´ ardenas-Gonz´ alez et al. (2016) p N-acetyl-beta-D-glucosaminidase (NAG) r See information related to Cd nephrotoxicity Wang et al. (2011)C´ ardenas-Gonz´ alez et al. (2016) p Cd Immunotoxicity/inflammatory effect Values of blood counts Alterations of values of blood counts, i. e. values of neutrophils and lymphocytes, are regarded as a marker of early immunotoxicity. Ciarrocca et al. (2015) Altered distribution of T cell populations Shifts of T-cell subpopulations as innate elements of the immune system are markers of early immunomodulatory effects. Altered distribution of T cell populations at birth could cause immunosuppressive effects observed later in childhood (Nygaard et al., 2017). Nygaard et al. (2017) Ohsawa et al. (2009) Induction of autoantibodies Associated to polyclonal B cell activation, T-cell mediated immunostimulation via cytokines and recognition of MHC-II antigens of cell surface including induction of autoantibodies was found to be the primary immunotoxic effect of Cd and can be linked to autoimmune diseases (Ohsawa et al., 2009). Ohsawa et al. (2009) Cr(VI) Immunotoxicity/inflammatory effect High-sensitivity C-reactive protein (hs-CRP) CRP is an acute phase protein synthesized by the liver in response to interleukin-6 secretion by macrophages and T cells, being a nonspecific biomarker of inflammation. Serum Hs-CRP was significantly elevated in Cr(VI)-exposed workers. Jamilian et al. (2016) Wang et al. (2012) Lymphocyte induced proliferation This assay evaluates the proliferative response of lymphocytes, and is usually performed in the presence of a mitogen, a polyclonal activator of lymphocytes that stimulates their proliferation (lymphocyte mitogen-induced proliferation). It is used to evaluate the subject cellmediated immune responsiveness. The lymphocyte proliferative response to mitogens was higher in shoe, hide, and leather industry workers exposed to Cr(VI). Lymphocytes of Cr allergic contact dermatitis patients were also stimulated by Cr, but in this case the lymphocyte proliferative response had low sensitivity. Mignini et al. (2009) Glucocorticoid receptors (GR) on peripheral blood mononucleate cells (PBMC) Mignini et al. (2009) (continued on next page) C. Ventura et al. Environmental Research 197 (2021) 110998 8 Table 1 (continued) Biomarker of effect Mechanistic relevance and link with health outcome References GR are ubiquitously expressed nuclear receptors to which cortisol and other glucocorticoids bind. Glucocorticoids are steroid hormones involved in several physiological functions and in controlling inflammation (Scheschowitsch et al., 2017). GR density on PBMC were lower in exposed workers versus controls indicating that Cr(VI) is probably an immunological stressor. Cytokines (Interleukins IL-2, IL-5, IL-6, IL-12 and IL-13) and interferon-gamma (IFN-γ) Cytokines are small, secreted proteins released by cells having a specific effect on the interactions and communications between cells. There are both antiand pro-inflammatory cytokines. The latter are produced predominantly by activated macrophages and involved in the upregulation of inflammatory reactions (Zhang and An, 2007). IL-2, IL-5, IL-6 and IL-12 are pro-inflammatory cytokines that were raised upon Cr exposure, as well as IFN-γ.IFN-γ is primarily secreted by activated T cells and natural killer cells, and can promote macrophage activation, mediate antiviral and antibacterial immunity, enhance antigen presentation, orchestrate activation of the innate immune system, coordinate lymphocyte–endothelium interaction, regulate T helper1/T helper 2 activity of CD4 + T cells balance, and control cellular proliferation and apoptosis (Tau and Rothman 1999). IL-13, a mediator of allergic inflammation, showed higher levels in Cr allergic contact dermatitis patients. Martins and Reis (2013) Club (Clara) cell protein (CC16) and surfactant-associated protein D (SP-D) CC16 CC16, as an immunosuppressive protein, and CC16/SP-D were positively associated with indicators of lung injury and can be used as sensitive serum biomarkers for lung toxicity caused by Cr(VI) exposure. Li et al. (2015) Cd or Cr(VI) Other biomarkers/effects q Blood pressure (Cd) Altered blood pressure is commonly associated with cardiovascular disease. Boonprasert et al. (2011) Osorio-Ya˜ nez et al. (2016) Swaddiwudhipong et al. (2015) Bone demineralization (urinary calcium, deoxypyridinoline (DPD)) (Cd) Urinary calcium excretion is a determinant of bone mineral density. Deoxypyridinoline (DPD) represents a specific degradation product of mature collagen found in bones. It is excreted unmetabolized in urine and is a specific marker of bone resorption and osteoclastic activity. Two studies found urinary Cd concentrations associated with B2-MG, U-Ca and DPD levels. Sughis et al. (2011) Eom et al. (2017) Bone mass density (Cd) Decreasing bone mass density is associated with cadmium-induced bone disorders. Trzcinka-Ochocka et al. (2010) Increased susceptibility to chronic infections (Cd) Commonly linked to reduced immune functions. Krueger and Wade (2016) Serum folate level (Cr(VI)) Long-term Cr (VI) exposure has been associated with decreased serum folate, an essential vitamin, and a cofactor in one-carbon metabolism ( Wang et al. 2011, 2012). Epidemiological and experimental evidences have shown that folate deficiency may be implicated in cancer development, e.g., lung and colorectum cancer (Ozkan et al., 2007) and thereby serum folate level is a promising marker of early Cr(VI) effects that needs, however, to be further studied. Wang et al., (2011), 2012 a Analysed in buccal exfoliated cells. b Occupational exposure to chromium and cobalt. c Environmental exposure to potentially carcinogenic compounds, including chromium, cadmium, nickel, arsenic, PAHs, benzene, pesticides, etc. d Occupational exposure to chromium, iron, and manganese. e DNA-protein crosslinks measured in blood lymphocytes. f Environmental or occupational co-exposure to metal(loids) including cadmium, chromium, arsenic, manganese, nickel, lead, and selenium. g Occupational co-exposure to cadmium, chromium, lead, and nickel. h Environmental co-exposure to chromium and cadmium. i Chromium and cobalt exposure in patients with metal-on-metal hip resurfacing. j Environmental exposure to chromium, cadmium, lead, copper, nickel, and zinc. k Environmental exposure to chromium, cadmium, lead, copper, nickel, cobalt, manganese, iron, and zinc. l Environmental exposure to toxic waste; biomarkers measured in semen. m Occupational exposure to chromium, iron and nickel. n Occupational exposure to chromium, cadmium, arsenic, lead and nickel. o Occupational exposure to chromium and aluminium. p Environmental exposure to chromium and arsenic. q Biomarkers identified during the literature search that were not associated with the selected health effects. These biomarkers were included because they may provide additional useful information. r Biomarker reported for Cr(VI) or Cd exposure. C. Ventura et al. Environmental Research 197 (2021) 110998 9 eligible (Fig. 1A). One of these articles was excluded afterwards because it consisted of a re-analysis of pre-existent data. The literature searches on Cr(VI)-associated cancer resulted in 173 articles either after using the search terms “Cr(VI)” and “cancer” or after more targeted queries for Cr (VI) and stomach cancer (10), respiratory cancer (29) and lung cancer (51); from these, 117 were considered eligible (Fig. 1B). Out of these, 26 studies were observational, 3 were data modelling or meta-analyses, and 88 were experimental, using either mammalian cell lines (42 articles), animal models (41 articles) or both (5 articles). Those in vitro and in vivo studies reporting mechanistic information about Cr(VI) were selected for a more detailed analysis (Fig. 1B). With respect to Cd, a total of 582 articles were found, of which 81 publications were eligible (Fig. 2). Relevant information on effect markers for oxidative stress (3 articles), nephrotoxicity (32 articles), and immunotoxicity (3 articles) is summarized in Table 1. Seven more articles provided information on additional markers, which were included in Table 1. Most biomarkers analysed in the epidemiological studies on Cr(VI) exposure targeted oxidative stress (Table 1). For example, 9 out of the 49 articles selected for a full text analysis reported significantly high levels of 8-hydroxy-2’-deoxyguanosine (8-OHdG) and eight of malondialdehyde (MDA), three reported depletion of glutathione (GSH) and three showed a depletion of superoxide dismutase (SOD). Additionally, biomarkers of genetic damage in blood cells were also frequently used. Regarding Cd, most of the biomarkers retrieved by this search were related to nephrotoxicity and some to oxidative stress and immunotoxicity (Table 1). 4. Discussion 4.1. Established effect biomarkers 4.1.1. Cr(VI) exposure, genotoxicity and cancer Since Cr(VI) is known to induce, either directly or indirectly via oxidative stress, DNA strand-breaks and, consequently, chromosomal alterations, these endpoints have been frequently analysed (9 out of 49 studies) in workers performing several activities, e.g., electroplating, welding, and leather tanning (Table 1). Two non-occupational studies, one in patients undergoing fixed orthodontic therapy (Angeleri et al., 2011) and another one in adolescents (Franken et al., 2017) included the characterization of chromosome damage (micronuclei in exfoliated cells from oral mucosa) or DNA damage (comet assay), respectively. The analysis of micronuclei in cytokinesis-blocked lymphocytes was included in the majority of these studies (Balachandar et al., 2010; Xiaohua et al., 2012; Li et al. 2014, 2016; Sudha et al., 2011), frequently in combination with the assessment of DNA damage (Balachandar et al., 2010; Sudha et al., 2011) or oxidative damage (e.g., 8-OHdG) (Li et al. 2014, 2016). Notably, the frequency of micronuclei in lymphocytes was significantly increased in all studies and, in some of them, correlations were established with exposure biomarkers (Xiaohua et al., 2012; Zhang et al., 2011). Some studies have also reported an increase of DNA strand breaks in lymphocytes of workers exposed to Cr(VI) (Zhang et al., 2011). Franken et al. (2017) reported a positive association between biomarkers of exposure to Cr and the levels of both 8-OHdG in urine and DNA damage in blood cells from the adolescent population of Flanders. Balachandar et al. (2010) combined the analyses of chromosome aberrations, micronuclei and DNA damage (comet assay) in peripheral blood cells and found a higher degree of genetic alterations in 72 Cr (VI)-exposed subjects (36 occupationally exposed in leather tannery industries and 36 environmentally exposed due to their residence in the vicinity of tannery industries) compared to non-exposed individuals. An increase in micronuclei frequency was also detected in cytological smears of tobacco user’s tannery workers (Kamil et al., 2019), but it was not observed in epithelial nasal or buccal cells neither in patients undergoing fixed orthodontic therapy (Angeleri et al., 2011) nor in chrome plating workers (Wultsch et al., 2017). The mutation frequency of T-cell receptor (TCR) was included in a study. This is not a widely adopted effect biomarker and thereby its value has not been proven, although gene mutations are frequent events in malignant cells. Overall, these studies evidenced a clear genotoxic effect associated with Cr(VI) exposure, and confirm the high sensitivity of genotoxicity biomarkers for the biomonitoring of exposed groups in occupational settings. Not surprisingly, test methods for measuring chromosome aberrations, micronuclei, and DNA strand breaks (comet assay) have been adopted as OECD Test Guidelines (OECD TGs 474, 475, 489). It is well-accepted that genetic damage will eventually lead to cancer; hence, safety testing strategies for carcinogenic effects in chemical risk assessment are usually based on proving absence of genotoxic potential (Luijten et al., 2016). Indeed, an increased chromosome breakage or micronuclei frequency in human blood cells (usually lymphocytes) has been associated with increased cancer risk (Bofetta et al., 2007; Bonassi et al., 2011). A similar association has not been demonstrated for the comet assay in human blood cells, yet. 4.1.2. Cd or Cr(VI) exposure and nephrotoxicity Most of the identified effect biomarkers were related to nephrotoxicity at urinary concentrations >4 μ g Cd/g creatinine (Table 1) (Nordberg et al. 2015, 2018). Associations reported at lower urinary Cd levels (<1 μ g/g creatinine) are insofar questionable as various confounding factors (renal physiology, diuresis, smoking), may lead to non-causal positive associations. Therefore, blood rather than urine markers were suggested as a better alternative for future studies to assess Cd-associated health risks (Bernard 2016, Stajnko et al., 2017). A single biomarker is rarely sufficient to clearly define a certain pathological condition of the kidney (Ferguson et al., 2008; Ostermann et al., 2020a). It is recommended to use sets of biomarkers to diagnose acute kidney injury (AKI) that is reversible in many cases, acute kidney disease (AKD), and chronic kidney disease (CKD) (for clinical definition of kidney disease see Ostermann et al. (2020b)). Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule (KIM)-1 are among the most frequently mentioned biomarkers that predict AKI in an early stage (Wasung et al., 2015, Nickolas et al., 2018), also in newborns (Askenazi et al., 2012). NGAL, a 25 kDa glycoprotein produced by epithelial tissues, is excreted via glomerular filtration und undergoes complete reabsorption in healthy tubular cells. NGAL is a marker of injury not of normal function and serves also as a marker in diagnosis of CKD (Ronco et al., 2014). KIM-1 is a type 1 transmembrane protein, whose expression is markedly upregulated in proximal tubule cells from patients with acute tubular necrosis. Since 2002, the soluble form of human KIM-1 in urine has been considered a useful and early biomarker for AKI and renal proximal tubule injury (Han et al., 2002). This was confirmed in 2007 in a study of Cd-induced nephrotoxicity in rats in which KIM-1 appeared in urine 4–5 weeks before the onset of proteinuria and 1–3 weeks before the appearance of metallothionein (MT) and Clara cell protein (CC-16) (Prozialeck et al., 2007). Findings that were later substantiated by a thorough description of the potential underlying pathomechanisms (Prozialeck and Edwards 2012). Accurate markers for the diagnosis of CKD include NGAL, Cystatin C (marker of GFR), liver-type fatty acid protein (L-FABP; marker of tubular cell damage), B2-MG (marker of GFR), and serum β-trace protein (BTP; marker of GFR) among others (Nickolas et al., 2008; Wasung et al., 2015; Foster et al., 2016; Tummalapalli et al., 2016). It should be noted that several markers such as Cystatin-C, NGAL, L-FABP, or NAG can be analysed in plasma as well as in urine, but the significance may vary. For example, plasma Cystatin-C may be a marker of GFR (i.e. a marker of kidney function), whereas it is detectable in urine only after tubular injury (Ostermann et al., 2012). Among the established biomarkers, B2-MG, NAG and α 1-microglobulin ( α 1-MG), which is preferred over B2-MG in case of acidic urine (pH <6), are the most frequently used biomarkers linking Cd exposure to renal tubular dysfunction (Table 1). In a recent study from China, B2MG was shown to be a more sensitive marker than NAG for renal dysfunction, with 2.2 μ g/g cr as threshold for clinical diagnosis (Li et al., C. Ventura et al. Environmental Research 197 (2021) 110998 16 Chen, Q.Y., DesMarais, T., Costa, M., 2019a. Metals and mechanisms of carcinogenesis. Annu. Rev. Pharmacol. Toxicol. 59, 537–554. https://doi.org/10.1146/annurevpharmtox-010818-021031. Chen, Q.Y., Murphy, A., Sun, H., Costa, M., 2019b. Molecular and epigenetic mechanisms of Cr(VI)-induced carcinogenesis. Toxicol. Appl. Pharmacol. 377, 114636. https:// doi.org/10.1016/j.taap.2019.114636. Chen, X., Ba, Y., Ma, L., Cai, X., Yin, Y., Wang, K., et al., 2008. Characterization of microRNAs in serum: a novel class of biomarkers for diagnosis of cancer and other diseases. Cell Res. 18 (10), 997–1006. https://doi.org/10.1038/cr.2008.282. Chen, X., Zhu, G., Wang, Z., Zhou, H., He, P., Liu, Y., Jin, T., 2019. The association between lead and cadmium co-exposure and renal dysfunction. Ecotoxicol. Environ. Saf. 173, 429–435. https://doi.org/10.1016/j.ecoenv.2019.01.121. Christie, N.T., Cantoni, O., Evans, R.M., Meyn, R.E., Costa, M., 1984. Use of mammalian DNA repair-deficient mutants to assess the effects of toxic metal compounds on DNA. Biochem. Pharmacol. 33, 1661–1670. Chung, F.F.-L., Herceg, Z., 2020. The promises and challenges of toxico-epigenomics: environmental chemicals and their impacts on the epigenome. Environ. Health Perspect. 128, 15001. https://doi.org/10.1289/EHP6104. Ciarrocca, M., Rosati, M.V., Tomei, F., Pacchiarotti, A., Corbosiero, P., Di Pastena, C., Scala, B., Capozzella, A., Tomei, G., Caciari, T., Sacco, C., Sancini, A., 2015. Correlation between cadmium and blood counts in workers exposed to urban stressor. Arch. Environ. Occup. Health 70, 70–76. https://doi.org/10.1080/ 19338244.2013.778807. Coelho, P., García-Lest´ on, J., Costa, S., Costa, C., Silva, S., Dall’Armi, V., Zoffoli, R., Bonassi, S., de Lima, J.P., Gaspar, J.F., P´ asaro, E., Laffon, B., Teixeira, J.P., 2013. Genotoxic effect of exposure to metal(loid)s. A molecular epidemiology survey of populations living and working in Panasqueira mine area, Portugal. Environ. Int. 60, 163–170. https://doi.org/10.1016/j.envint.2013.08.014. Comhair, S.A., Erzurum, S.C., 2002. Antioxidant responses to oxidant mediated lung diseases. Am. J. Physiol. Lung Cell Mol. Physiol. 283, L246–L255. https://doi.org/ 10.1152/ajplung.00491.2001. Corradi, M., Goldoni, M., Mutti, A., 2015. A review on airway biomarkers: exposure, effect and susceptibility. Expet Rev. Respir. Med. 9, 205–220. https://doi.org/ 10.1586/17476348.2015.1001373. Çuhadar, S., Semerci, T., 2016. Renal biomarkers N-Acetyl-Beta-d-Glucosaminidase (NAG), endothelin, and their application. In: Patel, V., Preedy, V. (Eds.), Biomarkers in Kidney Disease. Biomarkers in Disease: Methods, Discoveries and Applications. Springer, Dordrecht. Cuypers, A., Plusquin, M., Remans, T., Jozefczak, M., Keunen, E., Gielen, H., Opdenakker, K., Nair, A.R., Munters, E., Artois, T.J., Nawrot, T., Vangronsveld, J., Smeets, K., 2010. Cadmium stress: an oxidative challenge. Biometals 23, 927–940. https://doi.org/10.1007/s10534-010-9329-x. Dalle-Donne, I., Rossi, R., Colombo, R., Giustarini, D., Milzani, A., 2006. Biomarkers of oxidative damage in human disease. Clin. Chem. 5, 601–623. DeLoughery, Z., Luczak, M.W., Ortega-Atienza, S., Zhitkovich, A., 2015. DNA doublestrand breaks by Cr(VI) are targeted to euchromatin and cause ATRdependent phosphorylation of histone H2AX and its ubiquitination. Toxicol. Sci. 143, 54–63. https://doi.org/10.1093/toxsci/kfu207. Ding, S.-Z., Yang, Y.-X., Li, X.-L., Michelli-Rivera, A., Han, S.-Y., Wang, L., Pratheeshkumar, P., Wang, X., Lu, J., Yin, Y.-Q., Budhraja, A., Hitron, A.J., 2013. Epithelial-mesenchymal transition during oncogenic transformation induced by hexavalent chromium involves reactive oxygen species-dependent mechanism in lung epithelial cells. Toxicol. Appl. Pharmacol. 269, 61–71. https://doi.org/ 10.1016/j.taap.2013.03.006. Domingos, M.A., Moreira, S.R., Gomez, L., Goulart, A., Lotufo, P.A., Bense˜ nor, I., Titan, S., 2016. Urinary retinol-binding protein: relationship to renal function and cardiovascular risk factors in chronic kidney disease. PloS One 11, e0162782. https://doi.org/10.1371/journal.pone.0162782. Dudka, I., Kossowska, B., Senhadri, H., Latajka, R., Hajek, J., Andrzejak, R., AntonowiczJuchniewicz, J., Gancarz, R., 2014. Metabonomic analysis of serum of workers occupationally exposed to arsenic, cadmium and lead for biomarker research: a preliminary study. Environ. Int. 68, 71–81. https://doi.org/10.1016/j. envint.2014.03.015. Dusinska, M., Collins, A.R., 2008. The comet assay in human biomonitoring: geneenvironment interactions. Mutagenesis 23 (3), 191–205. https://doi.org/10.1093/ mutage/gen007. EFSA, 2009. Cadmium in Food - Scientific Opinion of the Panel on Contaminants in the Food Chain [WWW Document]. European Food Safety Authority. URL. accessed July 13, 2020. https://www.efsa.europa.eu/en/efsajournal/pub/980. Elhosary, N., Maklad, A., Soliman, E., El-Ashmawy, N., Oreby, M., 2014. Evaluation of oxidative stress and DNA damage in cement and tannery workers in Egypt. Inhal. Toxicol. 26, 289–298. https://doi.org/10.3109/08958378.2014.885100. Ellinger-Ziegelbauer, H., Aubrecht, J., Kleinjans, J.C., Ahr, H.-J., 2009. Application of toxicogenomics to study mechanisms of genotoxicity and carcinogenicity. Toxicol. Lett. 186, 36–44. https://doi.org/10.1016/j.toxlet.2008.08.017. Ellis, J.K., Athersuch, T.J., Thomas, L.D.K., Teichert, F., P´ erez-Trujillo, M., Svendsen, C., Spurgeon, D.J., Singh, R., J¨ arup, L., Bundy, J.G., Keun, H.C., 2012. Metabolic profiling detects early effects of environmental and lifestyle exposure to cadmium in a human population. BMC Med. 10, 61. https://doi.org/10.1186/1741-7015-10-61. Eom, S.-Y., Seo, M.-N., Lee, Y.-S., Park, K.-S., Hong, Y.-S., Sohn, S.-J., Kim, Y.-D., Choi, B.- S., Lim, J.-A., Kwon, H.-J., Kim, H., Park, J.-D., 2017. Low-level environmental cadmium exposure induces kidney tubule damage in the general population of Korean adults. Arch. Environ. Contam. Toxicol. 73, 401–409. https://doi.org/ 10.1007/s00244-017-0443-4. Espín-P´ erez, A., de Kok, T.M.C.M., Jennen, D.G.J., Hendrickx, D.M., De Coster, S., Schoeters, G., Baeyens, W., van Larebeke, N., Kleinjans, J.C.S., 2015. Distinct genotype-dependent differences in transcriptome responses in humans exposed to environmental carcinogens. Carcinogenesis 36, 1154–1161. https://doi.org/ 10.1093/carcin/bgv111. Fang, Z., Zhao, M., Zhen, H., Chen, L., Shi, P., et al., 2014. Genotoxicity of triand hexavalent chromium compounds in vivo and their modes of action on DNA damage in vitro. PloS One 9 (8), e103194. https://doi.org/10.1371/journal.pone.0103194. Ferguson, M.A., Vaidya, V.S., Bonventre, J.V., 2008. Biomarkers of nephrotoxic acute kidney injury. Toxicology 245, 182–193. https://doi.org/10.1016/j. tox.2007.12.024. Foster, M.C., Coresh, J., Hsu, C.Y., et al., 2016. Serum β-trace protein and β2microglobulin as predictors of ESRD, mortality, and cardiovascular disease in adults with CKD in the chronic renal insufficiency cohort (CRIC) study. Am. J. Kidney Dis. 68 (1), 68–76. https://doi.org/10.1053/j.ajkd.2016.01.015. Franken, C., Koppen, G., Lambrechts, N., Govarts, E., Bruckers, L., Den Hond, E., Loots, I., Nelen, V., Sioen, I., Nawrot, T.S., Baeyens, W., Van Larebeke, N., Boonen, F., Ooms, D., Wevers, M., Jacobs, G., Covaci, A., Schettgen, T., Schoeters, G., 2017. Environmental exposure to human carcinogens in teenagers and the association with DNA damage. Environ. Res. 152, 165–174. https://doi.org/10.1016/j. envres.2016.10.012. Ganzleben, C., Antignac, J.-P., Barouki, R., Casta˜ no, A., Fiddicke, U., Kl´ anov´ a, J., Lebret, E., Olea, N., Sarigiannis, D., Schoeters, G.R., Sepai, O., Tolonen, H., KolossaGehring, M., 2017. Human biomonitoring as a tool to support chemicals regulation in the European Union. Int. J. Hyg Environ. Health 220, 94–97. https://doi.org/ 10.1016/j.ijheh.2017.01.007. Gao, Y., Lu, Y., Huang, S., Gao, L., Liang, X., Wu, Y., Wang, J., Huang, Q., Tang, L., Wang, G., Yang, F., Hu, S., Chen, Z., Wang, P., Jiang, Q., Huang, R., Xu, Y., Yang, X., Ong, C.N., 2014. Identifying early urinary metabolic changes with long-term environmental exposure to cadmium by mass-spectrometry-based metabolomics. Environ. Sci. Technol. 48, 6409–6418. https://doi.org/10.1021/es500750w. Gil, F., Hern´ andez, A.F., 2015. Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples. Food Chem. Toxicol. 80, 287–297. https://doi.org/10.1016/j.fct.2015.03.025. Goyal, T., Mitra, P., Singh, P., Sharma, P., Sharma, S., 2020. Evaluation of oxidative stress and pro-inflammatory cytokines in occupationally exposed cadmium workers. Work. https://doi.org/10.3233/WOR-203302. Grang´ e, G., Leguy, M.C., Tsatsaris, V., Guibourdenche, J., 2016. Fetal beta2microglobulin as a biomarker of kidney disease. In: Patel, V., Preedy, V. (Eds.), Biomarkers in Kidney Disease. Biomarkers in Disease: Methods, Discoveries and Applications. Springer, Dordrecht. Griffin, B.R., Faubel, S., Edelstein, C.L., 2019. Biomarkers of drug-induced kidney toxicity. Ther. Drug Monit. 41, 213–226. https://doi.org/10.1097/ ftd.0000000000000589. Grioni, S., Agnoli, C., Krogh, V., Pala, V., Rinaldi, S., Vinceti, M., et al., 2019. Dietary cadmium and risk of breast cancer subtypes defined by hormone receptor status: a prospective cohort study. Int. J. Canc. 144 (9), 2153–2160. Grass, D.S., Ross, J.M., Family, F., Barbour, J., James Simpson, H., Coulibaly, D., Hernandez, J., Chen, Y., Slavkovich, V., Li, Y., Graziano, J., Santella, R.M., BrandtRauf, P., Chillrud, S.N., 2010. Airborne particulate metals in the New York City subway: a pilot study to assess the potential for health impacts. Environ. Res. 110, 1–11. https://doi.org/10.1016/j.envres.2009.10.006. Gube, M., Ebel, J., Brand, P., G¨ oen, T., Holzinger, K., Reisgen, U., Kraus, T., 2010. Biological effect markers in exhaled breath condensate and biomonitoring in welders: impact of smoking and protection equipment. Int. Arch. Occup. Environ. Health 83, 803–811. https://doi.org/10.1007/s00420-010-0516-4. Hambach, R., Lison, D., D’Haese, P.C., Weyler, J., De Graef, E., De Schryver, A., Lamberts, L.V., van Sprundel, M., 2013. Co-exposure to lead increases the renal response to low levels of cadmium in metallurgy workers. Toxicol. Lett. 222, 233–238. https://doi.org/10.1016/j.toxlet.2013.06.218. Han, W.K., Bailly, V., Abichandani, R., Thadani, R., Bonventre, J.V., 2002. Kidney Injury Molecule-1 (KIM-1): a novel biomarker for human renal proximal tubule injury. Kidney Int. 62 (1), 237–244. https://doi.org/10.1046/j.1523-1755.2002.00433.x. He, Y., Zou, L., Luo, W., Yi, Z., Yang, P., Yu, S., Liu, N., Ji, J., Guo, Y., Liu, P., He, X., Lv, Z., Huang, S., 2020. Heavy metal exposure, oxidative stress and semen quality: exploring associations and mediation effects in reproductive-aged men. Chemosphere 244, 125498. https://doi.org/10.1016/j.chemosphere.2019.125498. Hoffmeyer, F., Raulf-Heimsoth, M., Weiss, T., Lehnert, M., Gawrych, K., Kendzia, B., Harth, V., Henry, J., Pesch, B., Brüning, T., WELDOX Study Group, 2012. Relation between biomarkers in exhaled breath condensate and internal exposure to metals from gas metal arc welding. J. Breath Res. 6, 027105 https://doi.org/10.1088/17527155/6/2/027105. Hossain, M.B., Vahter, M., Concha, G., Broberg, K., 2012. Low-level environmental cadmium exposure is associated with DNA hypomethylation in Argentinean women. Environ. Health Perspect. 120, 879–884. https://doi.org/10.1289/ehp.1104600. Hu, G., Li, P., Li, Y., Wang, T., Gao, X., Zhang, W., Jia, G., 2016. Methylation levels of P16 and TP53 that are involved in DNA strand breakage of 16HBE cells treated by hexavalent chromium. Toxicol. Lett. 249, 15–21. https://doi.org/10.1016/j. toxlet.2016.03.003. Hu, G., Wang, T., Liu, J., Chen, Z., Zhong, L., Yu, S., Zhao, Z., Zhai, M., Jia, G., 2017. Serum protein expression profiling and bioinformatics analysis in workers occupationally exposed to chromium (VI). Toxicol. Lett. 277, 76–83. https://doi. org/10.1016/j.toxlet.2017.05.026. Hu, G., Li, P., Cui, X., Li, Y., Zhang, J., Zhai, X., Yu, S., Tang, S., Zhao, Z., Wang, J., Jia, G., 2018. Cr(VI)-induced methylation and down-regulation of DNA repair genes and its association with markers of genetic damage in workers and 16HBE cells. Environ. Pollut. 238, 833–843. https://doi.org/10.1016/j.envpol.2018.03.046. C. Ventura et al. Environmental Research 197 (2021) 110998 17 Huang, M., Choi, S.-J., Kim, D.-W., Kim, N.-Y., Park, C.-H., Yu, S.-D., et al., 2009. Risk assessment of low-level cadmium and arsenic on the kidney. J. Toxicol. Environ. Health Part A72 (21–22), 1493–1498. https://doi.org/10.1080/ 15287390903213095. IARC, 2012. Chromium (VI) Compounds, IARC Monographs - Volume 100C, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Ikeda, M., Ohashi, F., Fukui, Y., Sakuragi, S., Moriguchi, J., 2011. Closer correlation of cadmium in urine than that of cadmium in blood with tubular dysfunction markers in urine among general women populations in Japan. Int. Arch. Occup. Environ. Health 84, 121–129. https://doi.org/10.1007/s00420-010-0527-1. Jamilian, M., Bahmani, F., Siavashani, M.A., Mazloomi, M., Asemi, Z., Esmaillzadeh, A., 2016. The effects of chromium supplementation on endocrine profiles, biomarkers of inflammation, and oxidative stress in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial. Biol. Trace Elem. Res. 172, 72–78. https://doi.org/10.1007/s12011-015-0570-6. J¨ arup, L., Åkesson, A., 2009. Current status of cadmium as an environmental health problem. Toxicol. Appl. Pharmacol. 238, 201–208. Jeddi, M., Hopf, N.B., Viegas, S., Price, A.B., Paini, A., van Thriel, C., Benfenati, E., Ndaw, S., Bessems, J., Behnisch, P.A., Leng, G., Duca, R.C., Verhagen, H., Cubadda, F., Brennan, L., Ali, I., David, A., Mustieles, V., Fernandez, M.F., Louro, H., Pasanen-Kase, R., 2020. Towards a systematic use of effect biomarkers in population and occupational biomonitoring. Environ. Int. 146, 106257. https://doi.org/ 10.1016/j.envint.2020.106257. Available online 15 December 2020. Jomova, K., Valko, M., 2011. Advances in metal-induced oxidative stress and human disease. Toxicology 283 (2–3), 65–87. https://doi.org/10.1016/j.tox.2011.03.001. Kalim, M.S., Khare, A., Shreedhar, B., Hadari, S., Gupta, V., Mahendra, A., 2019. The micronucleus assay in the oral exfoliated cells of tannery workers. J. Oral Maxillofac. Pathol. 23 (3), 474, 10.4103/jomfp.JOMFP_321_18. Ke, S., Cheng, X.-Y., Zhang, J.-Y., Jia, W.-J., Li, H., Luo, H.-F., Ge, P.-H., Liu, Z.-M., Wang, H.-M., He, J.-S., Chen, Z.-N., 2015. Estimation of the benchmark dose of urinary cadmium as the reference level for renal dysfunction: a large sample study in five cadmium polluted areas in China. BMC Publ. Health 15, 656. https://doi.org/ 10.1186/s12889-015-2021-x. Khan, F.H., Ambreen, K., Fatima, G., Kumar, S., 2012. Assessment of health risks with reference to oxidative stress and DNA damage in chromium exposed population. Sci. Total Environ. 430, 68–74. https://doi.org/10.1016/j.scitotenv.2012.04.063. Krueger, W.S., Wade, T.J., 2016. Elevated blood lead and cadmium levels associated with chronic infections among non-smokers in a cross-sectional analysis of NHANES data. Environ. Health 15, 16. https://doi.org/10.1186/s12940-016-0113-4. Kulathunga, M.R.D.L., AyankaWijayawardena, M.A., Naidu, R., Wijeratne, A.W., 2019. Chronic kidney disease of unknown aetiology in Sri Lanka and the exposure to environmental chemicals: a review of literature. Environ. Geochem. Health 41 (5), 2329–2338. https://doi.org/10.1007/s10653-019-00264-z. Lee, Y.K., Park, E.Y., Kim, Shiwon, Son, J.Y., Kim, T.H., Kang, W.G., Jeong, T.C., Kim, K.- B., Kwack, S.J., Lee, J., Kim, Suhkmann, Lee, B.-M., Kim, H.S., 2014. Evaluation of cadmium-induced nephrotoxicity using urinary metabolomic profiles in spraguedawley male rats. J. Toxicol. Environ. Health Part A 77, 1384–1398. https://doi.org/ 10.1080/15287394.2014.951755. Leist, M., Ghallab, A., Graepel, R., et al., 2017. Adverse outcome pathways: opportunities, limitations and open questions. Arch. Toxicol. 91, 3477–3505. https://doi.org/10.1007/s00204-017-2045-3. Lemaire, J., Van der Hauwaert, C., Savary, G., Dewaeles, E., Perrais, M., Lo Guidice, J.M., Pottier, N., Glowacki, F., Cauffiez, C., 2020. Cadmium-induced renal cell toxicity is associated with MicroRNA deregulation. Int. J. Toxicol. 39 (2), 103–114. https:// doi.org/10.1177/1091581819899039. Li, C., Park, S., Zhang, X., Eisenberg, L.M., Zhao, H., Darzynkiewicz, Z., Xu, D., 2017. Nuclear Gene 33/Mig6 regulates the DNA damage response through an ATM serine/ threonine kinase-dependent mechanism. J. Biol. Chem. 292, 16746–16759. https:// doi.org/10.1074/jbc.M117.803338. Li, H.H., Chen, R., Hyduke, D.R., Williams, A., Fr¨ otschl, R., Ellinger-Ziegelbauer, H., O’Lone, R., Yauk, C.L., Aubrecht, J., Fornace Jr., A.J., 2017. Development and validation of a high-throughput transcriptomic biomarker to address 21st century genetic toxicology needs. Proc. Natl. Acad. Sci. U. S. A. 114 (51), E10881–E10889. https://doi.org/10.1073/pnas.1714109114. Li, P., Gu, Y., Yu, S., Li, Y., Yang, J., Jia, G., 2014. Assessing the suitability of 8-OHdG and micronuclei as genotoxic biomarkers in chromate-exposed workers: a crosssectional study. BMJ Open4, e005979. https://doi.org/10.1136/bmjopen-2014005979. Li, P., Li, Y., Zhang, J., Yu, S.F., Tong, W., Hu, X., Jia, G., 2015. Biomarkers for lung epithelium injury in occupational hexavalent chromium-exposed workers. J. Occup. Environ. Med. 57, e45–50. https://doi.org/10.1097/JOM.0000000000000436. Li, Y., Li, P., Yu, S., Zhang, J., Wang, T., Jia, G., 2014. miR-3940-5p associated with genetic damage in workers exposed to hexavalent chromium. Toxicol. Lett. 229, 319–326. https://doi.org/10.1016/j.toxlet.2014.06.033. Li, Y., Hu, G., Li, P., Tang, S., Zhang, J., Jia, G., 2016. miR-3940-5p enhances homologous recombination after DSB in Cr(VI) exposed 16HBE cell. Toxicology 344–346. https://doi.org/10.1016/j.tox.2016.02.003, 1–6. Li, Y., Wang, H., Yu, J., Yan, Q., Hu, H., Zhang, L., Tian, T., Peng, X., Yang, S., Ke, S., 2020. An assessment of sensitivity biomarkers for urinary cadmium burden. BMC Nephrol. Sep 5 21 (1), 385. https://doi.org/10.1186/s12882-020-02036-9. Lin, C.-H., Lai, C.-H., Peng, Y.-P., Wu, P.-C., Chuang, K.-Y., Yen, T.-Y., Xiang, Y.-K., 2019. Comparative health risk of inhaled exposure to organic solvents, toxic metals, and hexavalent chromium from the use of spray paints in Taiwan. Environ. Sci. Pollut. Res. Int. 26 (33), 33906–33916. https://doi.org/10.1007/s11356-018-2669-8. Long, C., Liu, J., Hu, G., Feng, H., Zhou, D., Wang, J., Zhai, X., Zhao, Z., Yu, S., Wang, T., Jia, G., 2019. Modulation of homologous recombination repair gene polymorphisms on genetic damage in chromate exposed workers. Environ. Toxicol. Pharmacol. 66, 126–132. https://doi.org/10.1016/j.etap.2019.01.004. Louro, H., Hein¨ al¨ a, M., Bessems, J., Buekers, J., Vermeire, T., Woutersen, M., van Engelen, J., Borges, T., Rousselle, C., Ougier, E., Alvito, P., Martins, C., Assunç˜ ao, R., Silva, M.J., Pronk, A., Schaddelee-Scholten, B., Del Carmen Gonzalez, M., de Alba, M., Casta˜ no, A., Viegas, S., Humar-Juric, T., Kononenko, L., Lampen, A., Vinggaard, A.M., Schoeters, G., Kolossa-Gehring, M., Santonen, T., 2019. Human biomonitoring in health risk assessment in Europe: current practices and recommendations for the future. Int. J. Hyg Environ. Health 222, 727–737. https:// doi.org/10.1016/j.ijheh.2019.05.009. Luijten, M., Olthof, E.D., Hakkert, B.C., Rorije, E., van der Laan, J.W., Woutersen, R.A., van Benthem, J., 2016. An integrative test strategy for cancer hazard identification. Crit. Rev. Toxicol. 46, 615–639. https://doi.org/10.3109/10408444.2016.1171294. Martins, L.E.a.M., Reis, V.M.S., 2013. IL-13: a marker of chromium contact allergy. J. Eur. Acad. Dermatol. Venereol. 27, e390–393. https://doi.org/10.1111/ jdv.12005. McNeill, R.V., Mason, A.S., Hodson, M.E., Catto, J.W.F., Southgate, J., 2019. Specificity of the metallothionein-1 response by cadmium-exposed normal human urothelial cells. Int. J. Mol. Sci. 20 (6) https://doi.org/10.3390/ijms20061344. Medan, D., Luanpitpong, S., Azad, N., Wang, L., Jiang, B.-H., Davis, M.E., Barnett, J.B., Guo, L., Rojanasakul, Y., 2012. Multifunctional role of Bcl-2 in malignant transformation and tumorigenesis of Cr(VI)-transformed lung cells. PloS One 7, e37045. https://doi.org/10.1371/journal.pone.0037045. Mignini, F., Tomassoni, D., Traini, E., Vitali, M., Scuri, S., Baldoni, E., Grappasonni, I., Cocchioni, M., 2009. Immunological pattern alteration in shoe, hide, and leather industry workers exposed to hexavalent chromium. Environ. Toxicol. 24, 594–602. https://doi.org/10.1002/tox.20464. Mitchell, P.S., Parkin, R.K., Kroh, E.M., Fritz, B.R., Wyman, S.K., PogosovaAgadjanyan, E.L., et al., 2008. Circulating microRNAs as stable blood-based markers for cancer detection. Proc. Natl. Acad. Sci. U. S. A. 105, 10513–10518. 10.1073/ pnas.0804549105. Moriguchi, J., Inoue, Y., Kamiyama, S., Horiguchi, M., Murata, K., Sakuragi, S., Fukui, Y., Ohashi, F., Ikeda, M., 2009. N-acetyl-beta-D-glucosaminidase (NAG) as the most sensitive marker of tubular dysfunction for monitoring residents in non-polluted areas. Toxicol. Lett. 190, 1–8. https://doi.org/10.1016/j.toxlet.2009.05.009. Mozafari, P., Rezazadeh Azari, M., Shokoohi, Y., Sayadi, M., 2016. Feasibility of biological effective monitoring of chrome electroplaters to chromium through analysis of serum malondialdehyde. Int. J. Occup. Environ. Med. 7, 199–206. https://doi.org/10.15171/ijoem.2016.782. Mustieles, V., D’Cruz, S.C., Couderq, S., Rodríguez-Carrillo, A., Fini, J.-B., Hofer, T., Steffensen, I.L., Dirven, H., Barouki, R., Olea, N., Fern´ andez, M.F., David, A., 2020. Bisphenol A and its analogues: a comprehensive review to identify and prioritize effect biomarkers for human biomonitoring. Environ. Int. Manuscript Nov 144, 105811 (Accepted). Nascimento, S.N., G¨ oethel, G., Baierle, M., Barth, A., Brucker, N., Char˜ ao, M.F., Moro, A. M., Gauer, B., Sauer, E., Durgante, J., Arbo, M.D., Thiesen, F.V., Pierre, T.D.S., Gioda, A., Moresco, R., Garcia, S.C., 2017. Environmental exposure and effects on health of children from a tobacco-producing region. Environ. Sci. Pollut. Res. Int. 24, 2851–2865. https://doi.org/10.1007/s11356-016-8071-5. Ni, W., Huang, Y., Wang, X., Zhang, J., Wu, K., 2014. Associations of neonatal lead, cadmium, chromium and nickel co-exposure with DNA oxidative damage in an electronic waste recycling town. Sci. Total Environ. 472, 354–362. https://doi.org/ 10.1016/j.scitotenv.2013.11.032. Nickolas, T.L., Barasch, J., Devarajan, P., 2008. Biomarkers in acute and chronic kidney disease. Curr. Opin. Nephrol. Hypertens. 17 (2), 127–132. https://doi.org/10.1097/ MNH.0b013e3282f4e525. Nishijo, M., Suwazono, Y., Ruangyuttikarn, W., Nambunmee, K., Swaddiwudhipong, W., Nogawa, K., Nakagawa, H., 2014. Risk assessment for Thai population: benchmark dose of urinary and blood cadmium levels for renal effects by hybrid approach of inhabitants living in polluted and non-polluted areas in Thailand. BMC Publ. Health 14, 702. https://doi.org/10.1186/1471-2458-14-702. Nordberg, G.F., 2009. New insights into the mechanisms of cadmium toxicity - advances in cadmium research. Toxicol. Appl. Pharmacol. 238 (3), 192–200. https://doi.org/ 10.1016/j.taap.2009.03.015. Nordberg, G.F., Jin, T., Wu, X., Lu, J., Chen, L., Lei, L., Hong, F., Nordberg, M., 2009. Prevalence of kidney dysfunction in humans - relationship to cadmium dose, metallothionein, immunological and metabolic factors. Biochimie 91, 1282–1285. https://doi.org/10.1016/j.biochi.2009.06.014. Nordberg, G.F., Nogawa, K., Nordberg, M., 2015. Cadmium. In: Nordberg, G.F., Fowler, B.A., Nordberg, M. (Eds.), Handbook on the Toxicology of Metals. Elsevier, Academic Press, USA, pp. 667–716. https://www.elsevier.com/books/handbook-o n-the-toxicology-of-metals/nordberg/978-0-444-59453-2. Nordberg, G.F., Bernard, A., Diamond, G.L., Duffus, J.H., Illing, P., Nordberg, M., et al., 2018. Risk assessment of effects of cadmium on human health (IUPAC Technical Report). Pure Appl. Chem. 90 (4), 755–808. https://doi.org/10.1515/pac-20160910. NRC, 2006. Human Biomonitoring for Environmental Chemicals. National Research Council, Division on Earth and Life Studies, Board on Environmental Studies and Toxicology, Committee on Human Biomonitoring for Environmental Toxicants. National Academies Press. Nygaard, U.C., Li, Z., Palys, T., Jackson, B., Subbiah, M., Malipatlolla, M., Sampath, V., Maecker, H., Karagas, M.R., Nadeau, K.C., 2017. Cord blood T cell subpopulations and associations with maternal cadmium and arsenic exposures. PloS One 12, e0179606. https://doi.org/10.1371/journal.pone.0179606. C. Ventura et al. Environmental Research 197 (2021) 110998 18 OECD, 2013. Guidance Document on Developing and Asssessing Adverse Outcome Pathways; Series on Testing and Assessment No. 184. OECD Environment, Health and Safety Publications. Ohsawa, M., 2009. [Heavy metal-induced immunotoxicity and its mechanisms]. Yakugaku Zasshi 129, 305–319. https://doi.org/10.1248/yakushi.129.305. Osorio-Ya˜ nez, C., Gelaye, B., Miller, R.S., Enquobahrie, D.A., Baccarelli, A.A., Qiu, C., Williams, M.A., 2016. Associations of maternal urinary cadmium with trimesterspecific blood pressure in pregnancy: role of dietary intake of micronutrients. Biol. Trace Elem. Res. 174, 71–81. https://doi.org/10.1007/s12011-016-0705-4. Ostermann, M., Philips, B.J., Forni, L.G., 2012. Clinical review: biomarkers of acute kidney injury: where are we now? Crit. Care 16 (5), 233. https://doi.org/10.1186/ cc11380. Ostermann, M., Zarbock, A., Goldstein, S., et al., 2020a. Recommendations on acute kidney injury biomarkers from the acute disease quality initiative consensus conference: a consensus statement. JAMA Network Open 3 (10), e2019209. https:// doi.org/10.1001/jamanetworkopen.2020.19209. Ostermann, M., Bellomo, R., Burdmann, E.A., et al., 2020b. Controversies in acute kidney injury: conclusions from a kidney disease: improving global outcomes (KDIGO) conference. Kidney Int. 98 (2), 294–309. https://doi.org/10.1016/j. kint.2020.04.020. Ozkan, Y., Yardim-Akaydin, S., Firat, H., Calis¸ kan-Can, E., Ardiç, S., Sims¸ ek, B., 2007. Usefulness of homocysteine as a cancer marker: total thiol compoundsand folate levels in untreated lung cancer patients. Anticancer Res. 27, 1185–1189. Pan, C.-H., Jeng, H.A., Lai, C.-H., 2018. Biomarkers of oxidative stress in electroplating workers exposed to hexavalent chromium. J. Expo. Sci. Environ. Epidemiol. 28, 76–83. https://doi.org/10.1038/jes.2016.85. Paesano, L., Marmiroli, M., Bianchi, M.G., White, J.C., Bussolati, O., Zappettini, A., Villani, M., Marmiroli, N., 2020. Differences in toxicity, mitochondrial function and miRNome in human cells exposed in vitro to Cd as CdS quantum dots or ionic Cd. J. Hazard Mater. 393, 122430. https://doi.org/10.1016/j.jhazmat.2020.122430. Penders, J., Delanghe, J., 2004. Alpha 1-microglobulin: clinical laboratory aspects and applications. Clin. Chim. Acta 346, 107–118. https://doi.org/10.1016/j. cccn.2004.03.037. Pesch, B., Lotz, A., Koch, H.M., Marczynski, B., Casjens, S., K¨ afferlein, H.U., Welge, P., Lehnert, M., Heinze, E., Van Gelder, R., Hahn, J.-U., Behrens, T., Raulf, M., Hartwig, A., Weiss, T., Brüning, T., 2015. Oxidatively damaged guanosine in white blood cells and in urine of welders: associations with exposure to welding fumes and body iron stores. Arch. Toxicol. 89, 1257–1269. https://doi.org/10.1007/s00204014-1319-2. Pizzino, G., Bitto, A., Interdonato, M., Galfo, F., Irrera, N., Mecchio, A., Pallio, G., Ramistella, V., De Luca, F., Minutoli, L., Squadrito, F., Altavilla, D., 2014. Oxidative stress and DNA repair and detoxification gene expression in adolescents exposed to heavy metals living in the Milazzo-Valle del Mela area (Sicily, Italy). RedoxBiol 2, 686–693. https://doi.org/10.1016/j.redox.2014.05.003. Pournourmohammadi, S., Khazaeli, P., Eslamizad, S., Tajvar, A., Mohammadirad, A., Abdollahi, M., 2008. Study on the oxidative stress status among cement plant workers. Hum. Exp. Toxicol. 27, 463–469. https://doi.org/10.1177/ 0960327108094956. Prozialeck, W.C., Vaidya, V.S., Liu, J., Waalkes, M.P., Edwards, J.R., Lamar, P.C., Bernard, A.M., Dumont, X., Bonventre, J.V., 2007. Kidney injury molecule-1 is an early biomarker of cadmium nephrotoxicity. Kidney Int. 72 (8), 985–993. https:// doi.org/10.1038/sj.ki.5002467. Prozialeck, W.C., Edwards, J.R., 2012. Mechanisms of cadmium-induced proximal tubule injury: new insights with implications for biomonitoring and therapeutic interventions. J. Pharmacol. Exp. Therapeut. 343, 2–12. https://doi.org/10.1124/ jpet.110.166769. Prozialeck, W.C., VanDreel, A., Ackerman, C.D., Stock, I., Papaeliou, A., Yasmine, C., Wilson, K., Lamar, P.C., Sears, V.L., Gasiorowski, J.Z., DiNovo, K.M., Vaidya, V.S., Edwards, J.R., 2016. Evaluation of cystatin C as an early biomarker of cadmium nephrotoxicity in the rat. Biometals 29, 131–146. https://doi.org/10.1007/s10534015-9903-3. Ren, K., Li, Y., Lu, H., Li, Z., Han, X., 2017. miR-3940-5p functions as a tumor suppressor in non-small cell lung cancer cells by targeting cyclin D1 and ubiquitin specific peptidase-28. TranslOncol 10, 80–89. https://doi.org/10.1016/j. tranon.2016.11.004. Ronchetti, S.A., Novack, G.V., Bianchi, M.S., Crocco, M.C., Duvilanski, B.H., Cabilla, J.P., 2016. In vivo xenoestrogenic actions of cadmium and arsenic in anterior pituitary and uterus. Reproduction 152 (1), 1–10. https://doi.org/10.1530/rep-16-0115. Ronco, C., Legrand, M., Goldstein, S.L., et al., 2014. Neutrophil gelatinase-associated lipocalin: ready for routine clinical use? An international perspective. Blood Purif. 37 (4), 271–285. https://doi.org/10.1159/000360689. Roy, R.V., Pratheeshkumar, P., Son, Y.-O., Wang, L., Hitron, J.A., Divya, S.P., Zhang, Z., Shi, X., 2016. Different roles of ROS and Nrf2 in Cr(VI)-induced inflammatory responses in normal and Cr(VI)-transformed cells. Toxicol. Appl. Pharmacol. 307, 81–90. https://doi.org/10.1016/j.taap.2016.07.016. Sabbisetti, V.S., Waikar, S.S., Antoine, D.J., Smiles, A., Wang, C., Ravisankar, A., Ito, K., Sharma, S., Ramadesikan, S., Lee, M., Briskin, R., De Jager, P.L., Ngo, T.T., Radlinski, M., Dear, J.W., Park, K.B., Betensky, R., Krolewski, A.S., Bonventre, J.V., 2014. Blood kidney injury molecule-1 is a biomarker of acute and chronic kidney injury and predicts progression to ESRD in type I diabetes. J. Am. Soc. Nephrol. 25, 2177–2186. https://doi.org/10.1681/ASN.2013070758. Sabolic, I., 2006. Common mechanisms in nephropathy induced by toxic metals. Nephron. Physiol. 104 (3), 107–114. Saha, R., Nandi, R., Saha, B., 2011. Sources and toxicity of hexavalent chromium. J. Coord. Chem. 64, 1782–1806. https://doi.org/10.1080/00958972.2011.583646. Sanders, A.P., Smeester, L., Rojas, D., DeBussycher, T., Wu, M.C., Wright, F.A., Zhou, Y.- H., Laine, J.E., Rager, J.E., Swamy, G.K., Ashley-Koch, A., Lynn Miranda, M., Fry, R. C., 2014. Cadmium exposure and the epigenome: exposure-associated patterns of DNA methylation in leukocytes from mother-baby pairs. Epigenetics 9, 212–221. https://doi.org/10.4161/epi.26798. Sarma, S.N., Saleem, A., Lee, J.-Y., Tokumoto, M., Hwang, G.-W., Man Chan, H., Satoh, M., 2018. Effects of long-term cadmium exposure on urinary metabolite profiles in mice. J. Toxicol. Sci. 43, 89–100. https://doi.org/10.2131/jts.43.89. Savarino, L., Fotia, C., Roncuzzi, L., Greco, M., Cadossi, M., Baldini, N., Giannini, S., 2017. Does chronic raise of metal ion levels induce oxidative DNA damage and hypoxia-like response in patients with metal-on-metal hip resurfacing? J. Biomed. Mater. Res. B Appl. Biomater. 105, 460–466. https://doi.org/10.1002/jbm.b.33555. Schaap, M.M., Wackers, P.F., Zwart, E.P., Huijskens, I., Jonker, M.J., Hendriks, G., Breit, T.M., van Steeg, H., van de Water, B., Luijten, M., 2014. A novel toxicogenomics-based approach to categorize (non-)genotoxic carcinogens. Arch. Toxicol. 89, 2413–2427. Schaap, M.M., Zwart, E.P., Wackers, P.F., Huijskens, I., van de Water, B., Breit, T.M., van Steeg, H., Jonker, M.J., Luijten, M., 2012. Dissecting modes of action of nongenotoxic carcinogens in primary mouse hepatocytes. Arch. Toxicol. 86, 1717–1727. Scheschowitsch, K., Leite, J., Jamil, A., 2017. New insights in glucocorticoid receptor signaling – more than just a ligand binding receptor. Front. Endocrinol. 16. https ://www.frontiersin.org/article/10.3389/fendo.2017.00016. Serafim, A., Company, R., Lopes, B., Rosa, J., Cavaco, A., Castela, G., Castela, E., Olea, N., Bebianno, M.J., 2012. Assessment of essential and nonessential metals and different metal exposure biomarkers in the human placenta in a population from the south of Portugal. J. Toxicol. Environ. Health, Part A 75, 867–877. https://doi.org/10.1080/ 15287394.2012.690704. Son, Y.-O., Pratheeshkumar, P., Wang, Y., Kim, D., Zhang, Z., Shi, X., 2017. Protection from Cr(VI)-induced malignant cell transformation and tumorigenesis of Cr(VI)- transformed cells by luteolin through Nrf2 signaling. Toxicol. Appl. Pharmacol. 331, 24–32. https://doi.org/10.1016/j.taap.2017.04.016. Stackelberg, K. von, Guzy, E., Chu, T., Henn, B.C., 2015. Exposure to mixtures of metals and neurodevelopmental outcomes: a multidisciplinary review using an adverse outcome pathway framework. Risk Anal. 35 (6), 971–1016. https://doi.org/ 10.1111/risa.12425. Stearns, D.M., Kennedy, L.J., Courtney, K.D., Giangrande, P.H., Phieffer, L.S., Wetterhahn, K.E., 1995. Reduction of chromium(VI) by ascorbate leads to chromium-DNA binding and DNA strand breaks in vitro. Biochemistry 34 (3), 910–919. https://doi.org/10.1021/bi00003a025. Steffensen, I.L., Dirven, H., Couderq, S., David, A., D’Cruz, S.C., Fern´ andez, M.F., Mustieles, V., Rodríguez-Carrillo, A., Hofer, T., 2020. Bisphenols and oxidative stress biomarkers-associations found in human studies, evaluation of methods used, and strengths and weaknesses of the biomarkers. Int. J. Environ. Res. Publ. Health 17 (10), 3609. https://doi.org/10.3390/ijerph17103609. Sudha, S., Kripa, S.K., Shibily, P., Joseph, S., Balachandar, V., 2011. Biomonitoring of genotoxic effects among shielded manual metal arc welders. Asian Pac. J. Cancer Prev. APJCP 12, 1041–1044. Sughis, M., Penders, J., Haufroid, V., Nemery, B., Nawrot, T.S., 2011. Bone resorption and environmental exposure to cadmium in children: a cross–sectional study. Environ. Health 10, 104. https://doi.org/10.1186/1476-069X-10-104. Suh, M., Wikoff, D., Lipworth, L., Goodman, M., Fitch, S., Mittal, L., Ring, C., Proctor, D., 2019. Hexavalent chromium and stomach cancer: a systematic review and metaanalysis. Crit. Rev. Toxicol. 1–20. https://doi.org/10.1080/ 10408444.2019.1578730. Swaddiwudhipong, W., Limpatanachote, P., Mahasakpan, P., Krintratun, S., Punta, B., Funkhiew, T., 2012. Progress in cadmium-related health effects in persons with high environmental exposure in northwestern Thailand: a five-year follow-up. Environ. Res. 112, 194–198. https://doi.org/10.1016/j.envres.2011.10.004. Swaddiwudhipong, W., Mahasakpan, P., Jeekeeree, W., Funkhiew, T., Sanjum, R., Apiwatpaiboon, T., Phopueng, I., 2015. Renal and blood pressure effects from environmental cadmium exposure in Thai children. Environ. Res. 136, 82–87. https://doi.org/10.1016/j.envres.2014.10.017. Taooka, Y., Takeichi, N., Noso, Y., Kawano, N., Apsalikov, K., Hoshi, M., 2006. Increased T-cell receptor mutation frequency in radiation-exposed residents living near the Semipalatinsk nuclear test site. J. Radiat. Res. 47, 179–181. https://doi.org/ 10.1269/jrr.47.A179. Tau, G., Rothman, P., 1999. Biologic functions of the IFN-gamma receptors. Allergy 54, 1233–1251. https://doi.org/10.1034/j.1398-9995.1999.00099.x. Trzcinka-Ochocka, M., Jakubowski, M., Szymczak, W., Janasik, B., Brodzka, R., 2010. The effects of low environmental cadmium exposure on bone density. Environ. Res. 110, 286–293. https://doi.org/10.1016/j.envres.2009.12.003. Tsai, T.-L., Kuo, C.-C., Pan, W.-H., Chung, Y.-T., Chen, C.-Y., Wu, T.-N., Wang, S.-L., 2017. The decline in kidney function with chromium exposure is exacerbated with co-exposure to lead and cadmium. Kidney Int. 92, 710–720. https://doi.org/ 10.1016/j.kint.2017.03.013. Tummalapalli, L., Nadkarni, G.N., Coca, S.G., 2016. Biomarkers for predicting outcomes in chronic kidney disease. Curr. Opin. Nephrol. Hypertens. 25 (6), 480–486. https:// doi.org/10.1097/mnh.0000000000000275. Val, M.M., Mendes, L.A., Alarc˜ ao, A., Carvalho, L., Carreira, I., Rodrigues, C.F.D., Alpoim, M.C., 2015. Senescent bronchial fibroblasts induced to senescence by Cr(VI) promote epithelial-mesenchymal transition when co-cultured with bronchial epithelial cells in the presence of Cr(VI). Mutagenesis 30, 277–286. https://doi.org/ 10.1093/mutage/geu070. Valko, M., Izakovic, M., Mazur, M., Rhodes, C.J., Telser, J., 2004. Role of oxygen radicals in DNA damage and cancer incidence. Mol. Cell. Biochem. 266, 37–56. https://doi. org/10.1023/b:mcbi.0000049134.69131.89. C. Ventura et al. Environmental Research 197 (2021) 110998 19 Virani, S., Rentschler, K.M., Nishijo, M., Ruangyuttikarn, W., Swaddiwudhipong, W., Basu, N., Rozek, L.S., 2016. DNA methylation is differentially associated with environmental cadmium exposure based on sex and smoking status. Chemosphere 145, 284–290. https://doi.org/10.1016/j.chemosphere.2015.10.123. Wang, K.-C., Kuo, C.-H., Tian, T.-F., Tsai, M.-H., Chiung, Y.-M., Hsiech, C.-M., Tsai, S.-J., Wang, S.-Y., Tsai, D.-M., Huang, C.-C., Tseng, Y.J., 2012. Metabolomic characterization of laborers exposed to welding fumes. Chem. Res. Toxicol. 25, 676–686. https://doi.org/10.1021/tx200465e. Wang, L., Wise, J.T.F., Zhang, Z., Shi, X., 2016. Progress and prospects of reactive oxygen species in metal carcinogenesis. Curr Pharmacol Rep 2, 178–186. https://doi.org/ 10.1007/s40495-016-0061-2. Wang, T.C., Jia, G., Zhang, J., Ma, Y.H., Liu, L.Z., Zhang, N., Feng, W.Y., Zhou, J.W., Song, Y.S., Yan, L., Du, X.M., 2011. Vitamin B12 and folate deficiency and elevated plasma total homocysteine in workers with chronic exposure to chromate. Occup. Environ. Med. 68, 870–875. https://doi.org/10.1136/oem.2010.063305. Wang, T.C., Song, Y.S., Wang, H., Zhang, J., Yu, S.F., Gu, Y.E., Chen, T., Wang, Y., Shen, H.Q., Jia, G., 2012. Oxidative DNA damage and global DNA hypomethylation are related to folate deficiency in chromate manufacturing workers. J. Hazard Mater. 213–214, 440–446. https://doi.org/10.1016/j.jhazmat.2012.02.024. Wang, T., Feng, W., Kuang, D., Deng, Q., Zhang, W., Wang, S., He, M., Zhang, X., Wu, T., Guo, H., 2015. The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers. Environ. Res. 140, 405–413. https://doi.org/10.1016/j.envres.2015.04.013. Wasung, M.E., Chawla, L.S., Madero, M., 2015. Biomarkers of renal function, which and when? Clin. Chim. Acta 438, 350–357. https://doi.org/10.1016/j.cca.2014.08.039. Weaver, V.M., Kim, N.-S., Lee, B.-K., Parsons, P.J., Spector, J., Fadrowski, J., Jaar, B.G., Steuerwald, A.J., Todd, A.C., Simon, D., Schwartz, B.S., 2011. Differences in urine cadmium associations with kidney outcomes based on serum creatinine and cystatin C. Environ. Res. 111, 1236–1242. https://doi.org/10.1016/j.envres.2011.07.012. Welling, R., Beaumont, J.J., Petersen, S.J., Alexeeff, G.V., Steinmaus, C., 2015. Chromium VI and stomach cancer: a meta-analysis of the current epidemiological evidence. Occup. Environ. Med. 72, 151–159. https://doi.org/10.1136/oemed2014-102178. Wedrychowski, A., Ward, W.S., Schmidt, W.N., Hnilica, L.S., 1985. Chromium-induced cross-linking of nuclear proteins and DNA. J. Biol. Chem. 260, 7150–7155. WHO, 1993. Biomarkers and Risk Assessment: Concepts and Principles. World Health Organization. WHO, 2019. https://apps.who.int/iris/bitstream/handle/10665/329480/WHO-CEDPHE-EPE-19.4.3-eng.pdf?ua=1. Widhalm, R., Ellinger, I., Granitzer, S., Forsthuber, M., Bajtela, R., Gelles, K., Hartig, P.- Y., Hengstschl¨ ager, M., Zeisler, H., Salzer, H., Gundacker, C., 2020. Human placental cell line HTR-8/SVneo accumulates cadmium by divalent metal transporters DMT1 and ZIP14. Metall 12 (11), 1822–1833. https://doi.org/10.1039/d0mt00199f. Williams, M., Bozhilov, K., Ghai, S., Talbot, P., 2017. Elements including metals in the atomizer and aerosol of disposable electronic cigarettes and electronic hookahs. PloS One 12, e0175430. https://doi.org/10.1371/journal.pone.0175430. Wise, J.T.F., Wang, L., Alstott, M.C., Ngalame, N.N.O., Wang, Y., Zhang, Z., Shi, X., 2018a. Investigating the role of mitochondrial respiratory dysfunction during hexavalent chromium-induced lung carcinogenesis. J. Environ. Pathol. Toxicol. Oncol. 37, 317–329. https://doi.org/10.1615/ JEnvironPatholToxicolOncol.2018028689. Wise, S.S., Aboueissa, A.E.-M., Martino, J., Wise, J.P., 2018b. Hexavalent chromiuminduced chromosome instability drives permanent and heritable numerical and structural changes and a DNA repair-deficient phenotype. Cancer Res 78, 4203–4214. https://doi.org/10.1158/0008-5472.CAN-18-0531. Wu, W., Zhang, K., Jiang, S., Liu, D., Zhou, H., Zhong, R., Zeng, Q., Cheng, L., Miao, X., Tong, Y., Lu, Q., 2018. Association of co-exposure to heavy metals with renal function in a hypertensive population. Environ. Int. 112, 198–206. https://doi.org/ 10.1016/j.envint.2017.12.023. Wultsch, G., Nersesyan, A., Kundi, M., Miˇ sík, M., Setayesh, T., Waldherr, M., Vodicka, P., Vodickova, L., Knasmüller, S., 2017. Genotoxic and cytotoxic effects in exfoliated buccal and nasal cells of chromium and cobalt exposed electroplaters. J. Toxicol. Environ. Health Part A 80, 651–660. https://doi.org/10.1080/ 15287394.2017.1286918. Xiaohua, L., Yanshuang, S., Li, W., Yuhui, L., Ji, Z., Yanhui, M., Yun, W., Wenjun, M., Lei, Y., Guang, J., 2012. Evaluation of the correlation between genetic damage and occupational chromate exposure through BNMN frequencies. J. Occup. Environ. Med. 54, 166–170. Xu, J., Zhao, M., Pei, L., Zhang, R., Liu, X., Wei, L., Yang, M., Xu, Q., 2018. Oxidative stress and DNA damage in a long-term hexavalent chromium-exposed population in North China: a cross-sectional study. BMJ Open 8 (6), e021470. https://doi.org/ 10.1136/bmjopen-2017-021470. Xu, Y., Wang, J., Liang, X., Gao, Y., Chen, W., Huang, Q., Liang, C., Tang, L., Ouyang, G., Yang, X., 2016. Urine metabolomics of women from small villages exposed to high environmental cadmium levels. Environ. Toxicol. Chem. 35, 1268–1275. https://doi. org/10.1002/etc.3274. Yang, L., Xia, B., Yang, X., Ding, H., Wu, D., Zhang, H., Jiang, G., Liu, J., Zhuang, Z., 2016. Mitochondrial DNA hypomethylation in chrome plating workers. Toxicol. Lett. 243, 1–6. https://doi.org/10.1016/j.toxlet.2015.11.031. Yu, X., Hong, S., Faustman, E.M., 2008. Cadmium-induced activation of stress signaling pathways, disruption of ubiquitin-dependent protein degradation and apoptosis in primary rat Sertoli cell-gonocyte cocultures. Toxicol. Sci. 104, 385–396. https://doi. org/10.1093/toxsci/kfn087. Zendehdel, R., Shetab-Boushehri, S.V., Azari, M.R., Hosseini, V., Mohammadi, H., 2015. Chemometrics models for assessment of oxidative stress risk in chromeelectroplating workers. Drug Chem. Toxicol. 38, 174–179. https://doi.org/10.3109/ 01480545.2014.922096. Zhang, C., Liang, Y., Lei, L., Zhu, G., Chen, X., Jin, T., Wu, Q., 2013. Hypermethylations of RASAL1 and KLOTHO is associated with renal dysfunction in a Chinese population environmentally exposed to cadmium. Toxicol. Appl. Pharmacol. 271, 78–85. https://doi.org/10.1016/j.taap.2013.04.025. Zhang, J.M., An, J., 2007. Cytokines, inflammation, and pain. Int. Anesthesiol. Clin. 45, 27–37. https://doi.org/10.1097/AIA.0b013e318034194e. Zhang, X.-H., Zhang, X., Wang, X.-C., Jin, L.-F., Yang, Z.-P., Jiang, C.-X., Chen, Q., Ren, X.-B., Cao, J.-Z., Wang, Q., Zhu, Y.-M., 2011. Chronic occupational exposure to hexavalent chromium causes DNA damage in electroplating workers. BMC Publ. Health 11, 224. https://doi.org/10.1186/1471-2458-11-224. Zhang, Y., Liang, X., Chen, W., Wang, J., Huang, Q., Chen, Z., Wang, P., Huang, R., Hu, S., Li, Z., Tang, L., Wang, G., Yang, F., Li, X., Zhao, Y., Yang, X., Wu, Y., 2015. [Long-term effect of cadmium exposure on residents’ renal dysfunction: an epidemiologic study]. Zhonghua Yufang Yixue Zazhi 49, 638–643. Zhitkovich, A., 2011. Chromium in drinking water: sources, metabolism, and cancer risks. Chem. Res. Toxicol. 24, 1617–1629. https://doi.org/10.1021/tx200251t. C. Ventura et al.