Exposure to environmental chemicals among Korean adults-updates from the second Korean National Environmental Health Survey (2012-2014)

Reference values of trace elements in blood and/or plasma in adults living in Belgium

OBJECTIVES

Trace elements (TEs) from natural and anthropogenic sources are ubiquitous. Essential or not, their relevance for human health and disease is constantly expanding. Biological monitoring is a widely integrated tool in risk assessment both in occupational and environmental settings. However, the determination of appropriate and accurate reference values in the (specific) population is a prerequisite for a correct interpretation of biomonitoring data. This study aimed at determining the reference distribution for TEs (Al, As, Sb, Be, Bi, Cd, Co, Cu, Mn, Hg, Mo, Ni, Pb, Se, Tl, Sn, V, Zn) in the blood and/or plasma of the adult population in Belgium.

METHODS

Blood and plasma samples were analyzed for 178 males and 202 females, recruited according to an a priori selection procedure, by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Reference values were established with high confidence for AsT, Cd, Cu, HgT, Mn, Mo, Pb, Sn, Se, Tl and Zn. Compared to previously published data in the Belgian population, a decreasing time trend is observed for Zn, Cd and Pb. Globally, the results also indicate that the current exposure levels to TEs in the Belgian population are similar to those from other recent national surveys.

CONCLUSIONS

These reference values and limits obtained through validated analytical and statistical methods will be useful for future occupational and/or environmental surveys. They will contribute to decision-making concerning both public health policies but also exposure assessments on an individual scale.

Association of exposure to polycyclic aromatic hydrocarbons and heavy metals with thyroid hormones in general adult population and potential mechanisms

Air pollution and fuel emissions are the common sources of human exposure to polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Several studies have suggested potential associations between PAHs/heavy metals and thyroid hormones, however, reports have been inconsistent. In this study, we employed a subpopulation of the adults (n = 1254) who participated in the Korean National Environmental Health Survey 2015-2017, and investigated the association of PAHs and major heavy metals with thyroid hormones, and explored the underlying mechanisms of thyroid disruption. Four PAH metabolites and three heavy metals of lead (Pb), mercury (Hg), and cadmium (Cd) were measured either in urine or in total blood. In addition, thyroid hormones (T3 and T4), TSH, thyroxine-binding globulin (TBG), and thyroid autoantibodies were measured, and peripheral deiodinase activity (G_D) and thyroid's secretory capacity (G_T) were calculated. Urinary Hg was negatively associated with total T3 in both males and females, while it was positively associated with total T4 among females only. Urinary Hg was related to decreased G_D and increased G_T in both sexes. In contrast, urinary Cd was positively associated with total T3 and G_D in both male and female populations. Urinary Cd also showed a positive association with thyroid autoantibodies, but only in males. A multi-factor model considering co-exposure to multiple chemicals also resulted in similar associations. Among the measured PAH metabolites, only urinary 1-hydroxypyrene showed a negative association with total T3 in males. However, this association was marginal, and disappeared in a multi-chemical model. The present observations are suggestive that exposures to Hg and Cd might disrupt thyroid hormones, possibly through an alteration of deiodinase activity. Association of PAH exposure with thyroid hormone appears to be insignificant.

Total blood mercury and its determinants in New Zealand children and adults

BACKGROUND

Mercury is a widespread persistent environmental pollutant associated with adverse health effects.

OBJECTIVE

This first national biomonitoring survey of blood total mercury (tHg) conducted in New Zealand aimed to provide baseline data and identify exposure determinants.

METHODS

Blood was collected from 191 children (age 5-18 years) and 304 adults (20-65) in 2014-2016 and analysed for tHg using inductively coupled plasma mass spectrometry. Linear regression was used to assess associations with demographic and lifestyle factors.

RESULTS

Blood mercury was detected in 93% of children and 99% of adults, with geometric means (GMs) of 0.86 and 1.65 µg/L, respectively. The 60-65-year olds had the highest GM (2.34 µg/L). Regression indicated that tHg was 40% higher in boys compared to girls. Eating fish ≥ 3 times/week (compared to ≤once/week) was associated with 2.7 and 1.7 times higher tHg in children and adults, respectively. Shellfish consumption was also associated with higher tHg. High daily tap water consumption (≥2 L for children, ≥3 L for adults) was associated with lower tHg. In adults, smoking and milk consumption were associated with higher tHg.

SIGNIFICANCE

Fish and shellfish consumption is a strong determinant of New Zealanders blood tHg levels, with water and milk consumption possibly acting as modulating factors.

Urinary bisphenol A concentrations and the risk of obesity in Korean adults

This study was aimed to evaluate the association between urinary bisphenol A (BPA) levels and risk of obesity in Korean adults. We analyzed data from the Korean National Environmental Health Survey (KoNEHS) Cycle 2 (2012–2014) and Cycle 3 (2015–2017). A total of 10,021 participants aged ≥ 19 years were included. Urine dilution was corrected by the covariate-adjusted standardization (CAS) method. We performed meta-analysis, logistic regression analysis by matching all covariates with a 1:1 propensity score, and a 4-knot restricted cubic spline plot model to calculate the odds ratios (ORs) for obesity according to natural log-transformed BPA levels. Mean urinary BPA concentration was 1.12 µg/L in KoNEHS Cycle 2 and 1.32 µg/L in Cycle 3. BPA levels were significantly higher among obese adults than among non-obese adults in both KoNEHS Cycles 2 and 3. In pooled data of KoNEHS Cycles 2 and 3, BPA showed significant positive associations with ORs for obesity in both sexes, which were more prominent in females (linear) than in males (non-linear). These associations were confirmed in spline analyses. CAS-applied BPA concentrations were positively associated with obesity in nationwide representative samples of Korean adults. Further studies are warranted to confirm and elucidate the underlying mechanism.

Assessement of Blood Lead and Cadmium Levels in Occupationally Exposed Workers of Jodhpur, Rajasthan

In spite of the established knowledge regarding their toxicities, occupational exposure to heavy metals like lead and cadmium still continues because of their wide distribution in environment. Due to lack of awareness, most of the workers usually eat, smoke, drink at their workplace which may aggravate the metal exposure. The present study was planned to assess the blood levels of lead and cadmium in occupationally exposed workers of Jodhpur (India). A total of 110 individuals working in different industrial set ups (furniture, metal handicraft, welders) of Jodhpur district (exposed group), aged between 20 and 60 years and 97 apparently healthy people (controls) with no history of occupational heavy metal exposure aged between 25 and 60 were recruited. Details of personal habits and demographics were recorded by means of self-developed questionnaire. 5 ml of whole blood was drawn from every individual. Metal levels were measured by graphite furnace atomic absorption spectrophotometer. Statistical analysis was done using GraphPad Prism Software. Results showed that Blood Lead Level and Blood Cadmium Level (CdB) were significantly higher in the exposed group as compared to the non-exposed group. Significant age and gender-based differences were found in terms of blood cadmium levels but no such difference was observed in case of blood lead. The study also revealed that higher blood levels of these metals in workers are influenced by their occupational practices, lack of protection against workplace environment pollutants, thus increasing their susceptibility to metal toxicity.

The associations between personal care products use and urinary concentrations of phthalates, parabens, and triclosan in various age groups: The Korean National Environmental Health Survey Cycle 3 2015-2017

Phthalates and parabens are ubiquitous chemicals of public concern. This study aimed to investigate the use of personal care products (PCPs) as predictors of exposure to phthalates, parabens, and triclosan (TCS) among various age groups in a nationally representative population. The concentrations of eight phthalate metabolites, three parabens, and TCS were measured in a random spot urine sample in 5962 study participants (age range: 3-86 years). The information on PCPs use was obtained in seven categories over previous three months. The exposure risks to phthalates, parabens, and TCS were different according to the pattern of PCPs use in different age groups and gender. In adolescents and adults, females used all categories of PCPs more frequently than males, with statistical significance. The use rates of PCPs and the significant exposure risks to phthalates, parabens, and TCS associated with PCP use were more clearly observed in adults. The least square geometric means (LSGMs) of urinary methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) steadily increased, as the cumulative number of used PCPs increased with statistical significance. The exposure risks to MeP were consistently observed with various PCPs use and showed a significant increase as the cumulative number of PCPs use increased in adults. Furthermore, the use of fragrance products, makeup, and air fresheners significantly increased the exposure risk to EtP in preschoolers. The significant exposure risk to mono-(3-carboxypropyl)- phthalate (MCPP) associated with nail polishes use was observed in preschoolers and adults. This study showed the associations between PCPs use and urinary concentrations of phthalates, parabens, and TCS in various age groups. Environmental health policies to reduce exposure to phthalates and parabens should be widely implemented, including industry regulations and increasing public awareness. Future studies are needed to explore other important exposure sources of these chemicals and their related adverse health effects.

The association between mercury concentrations and lipid profiles in the Korean National Environmental Health Survey (KoNEHS) cycle 3

Background

High concentrations of mercury intake from seafood are known to cause various side effects in humans, including on the nervous system. Various studies have reported the effects of mercury concentrations in humans; however, the association between dyslipidemia, a cardiovascular disease risk factor, and mercury remains controversial. Therefore, this study aimed to investigate the association between mercury accumulation and cholesterol concentrations in a Korean population.

Methods

We analyzed data of a sample of 3,228 respondents obtained from the Korean National Environmental Health Survey cycle 3, surveyed between 2015 and 2017, to determine how lipid profiles changed according to the blood mercury concentrations (BHg) and urine mercury concentrations (UHg). Multiple regression analysis was used to determine the effects of mercury concentrations among various factors affecting blood cholesterol levels.

Results

The arithmetic mean (AM) of BHg was 2.91 (2.81–3.02) μg/L, and the geometric mean (GM) was 2.71 (2.59–2.85) μg/L. The AM of UHg was 0.52 (0.48–0.56) μg/L, and the GM was 0.35 (0.33–0.38) μg/L. Lipid profiles were more related to the BHg than to the UHg. Total cholesterol (total-C), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels increased significantly as BHg increased in males, and total-C, triglyceride, and LDL-C levels increased significantly in females. Multiple regression analysis indicated that BHg were significantly associated with total-C, HDL-C, and LDL-C levels.

Conclusions

We found an association between mercury exposure and the risk of dyslipidemia; however, further studies are required to elucidate a causal association.

Is It Realistic to Propose Determination of a Lifetime Internal Exposome?

Biomonitoring of xenobiotics has been performed for many years in occupational and environmental medicine. It has revealed hidden exposures and the exposure of workers could be reduced. Although most of the toxic effects of chemicals on humans were discovered in workers, the scientific community has more recently focused on environmental samples. In several countries, urinary and blood samples have been collected and analyzed for xenobiotics. Health, biochemical, and clinical parameters were measured in the biomonitoring program of the Unites States. The data were collected and evaluated as group values, comparing races, ages, and gender. The term exposome was created in order to relate chemical exposure to health effects together with the terms genome, proteome, and transcriptome. Internal exposures were mostly established with snapshot measurements, which can lead to an obvious misclassification of the individual exposures. Albumin and hemoglobin adducts of xenobiotics reflect the exposure of a larger time frame, up to 120 days. It is likely that only a small fraction of xenobiotics form such adducts. In addition, adduct analyses are more work intensive than the measurement of xenobiotics and metabolites in urine and/or blood. New technology, such as high-resolution mass spectrometry, will enable the discovery of new compounds that have been overlooked in the past, since over 300,000 chemicals are commercially available and most likely also present in the environment. Yet, quantification will be challenging, as it was for the older methods. At this stage, determination of a lifetime internal exposome is very unrealistic. Instead of an experimental approach with a large number of people, which is economically and scientifically not feasible, in silico methods should be developed further to predict exposure, toxicity, and potential health effects of mixtures. The computer models will help to focus internal exposure investigations on smaller groups of people and smaller number of chemicals.

Thyroxine-binding globulin, peripheral deiodinase activity, and thyroid autoantibody status in association of phthalates and phenolic compounds with thyroid hormones in adult population

Exposure to consumer chemicals such as phthalates and phenolic compounds has been associated with thyroid hormone disruption in humans. However, information related to factors that may influence such associations, e.g., transport and activation of the hormones, and autoimmunity status, is limited. In the present study, we employed a subpopulation of adults (n = 1,254) who participated in the Korean National Environmental Health Survey (KoNEHS) 2015-2017, and associated urinary concentrations of major phthalate metabolites, bisphenol A (BPA), and parabens, with thyroid hormone-related measures, including free and total T3 and T4, TSH, thyroxine-binding globulin (TBG), calculated peripheral deiodinase (DIO) activity, and thyroid autoantibodies of thyroperoxidase (TPO) and thyroglobulin (Tg). Phthalate metabolites were negatively associated with total T4 and free T3, and positively associated with total T3. These observations could be explained by TBG levels and calculated peripheral DIO activity that were positively associated with phthalates exposure. In contrast, BPA was positively associated with total T4 and negatively associated with total T3, without any changes in TBG concentration. Serum TPO and Tg antibodies were not associated with urinary phthalate metabolites and BPA. However, thyroid autoantibody status appeared to modulate the association of some phthalates with thyroid hormones. For parabens, little to negligible association was observed. The results of our observation show potential underlying mechanisms of phthalates-induced thyroid hormone disruption, and suggests the importance of consideration of thyroid autoimmunity status in association studies for thyroid disrupting chemicals.

Mercury Exposure and Associations with Hyperlipidemia and Elevated Liver Enzymes: A Nationwide Cross-Sectional Survey

Mercury (Hg) has obesogenic properties. However, the associated health outcomes of population-level mercury exposure were unclear. This study investigated the relationships between blood mercury levels and obesity-related outcomes such as hyperlipidemia and elevated liver enzymes. Using the second cycle of the Korean National Environmental Health Survey (n = 6454), we performed logistic regression to examine the effects of Hg on hyperlipidemia and elevated liver enzymes. The blood mercury levels were significantly higher in the hyperlipidemia group (n = 3699, male: 4.03 μg/L, female: 2.83 μg/L) compared to the non-hyperlipidemia group (n = 2755, male: 3.48 μg/L, female: 2.69 μg/L), and high blood mercury levels were associated with an 11% higher risk of hyperlipidemia. The elevated liver enzymes group had higher mean blood mercury levels (n = 1189, male: 4.38 μg/L, female: 3.25 μg/L) than the normal group (n = 5265, male: 3.64 μg/L, female: 2.70 μg/L), and elevated blood mercury was associated with a 35% higher risk of elevated liver enzymes. Moreover, the effect was constant after adjusting for personal medications. These results indicate that mercury exposure is significantly associated with hyperlipidemia and elevated liver enzymes.

Impact of pesticide coexposure: an experimental study with binary mixtures of lambda-cyhalothrin (LCT) and captan and its impact on the toxicokinetics of LCT biomarkers of exposure

This study aimed at gaining more insights into the impact of pesticide coexposure on the toxicokinetics of biomarkers of exposure. This was done by conducting an in vivo experimental case-study with binary mixtures of lambda-cyhalothrin (LCT) and captan and by assessing its impact on the kinetic profiles of LCT biomarkers of exposure. Groups of male Sprague-Dawley rats were exposed orally by gavage to LCT alone (2.5 or 12.5 mg/kg bw) or to a binary mixture of LCT and captan (2.5/2.5 or 2.5/12.5 or 12.5/12.5 mg/kg bw). In order to establish the temporal profiles of the main metabolites of LCT, serial blood samples were taken, and excreta (urine and feces) were collected at predetermined intervals up to 48 h post-dosing. Major LCT metabolites were quantified in these matrices: 3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropane carboxylic (CFMP), 3-phenoxybenzoic acid (3-PBA), 4-hydroxy-3-phenoxybenzoic acid (4-OH3PBA). There was no clear effect of coexposure at the low LCT dose on the kinetics of CFMP and 3-PBA metabolites, based on the combined assessment of temporal profiles of these metabolites in plasma, urine and feces; however, plasma levels of 3-PBA were diminished in the coexposed high-dose groups. A significant effect of coexposure on the urinary excretion of 4-OH3PBA was also observed while fecal excretion was not affected. The temporal profiles of metabolites in plasma and in excreta were further influenced by the LCT dose. In addition, the study revealed kinetic differences between metabolites with a faster elimination of 3-PBA and 4-OH3BPA compared to CFMP. These results suggest that the pyrethroid metabolites CFMP and 3-PBA, mostly measured in biomonitoring studies, remain useful as biomarkers of exposure in mixtures, when pesticide exposure levels are below the reference values. However, the trend of coexposure effect observed in the benzyl metabolite pathway (in particular 4-OH3BPA) prompts further investigation.

Comparison of Polycyclic Aromatic Hydrocarbons Exposure Across Occupations Using Urinary Metabolite 1-Hydroxypyrene

OBJECTIVES

Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens causing lung and skin cancers in exposed workers. Certain occupations, such as coke production, have been associated with high PAH exposure; however, the number of occupations tested to date remains small. Here, we sought to compare PAH exposure across a wide range of occupations based on levels of 1-hydroxypyrene (1-OHP), the urinary exposure surrogate of PAHs.

METHODS

We collected urine 1-OHP data from the Korean National Environmental Health Survey (KoNEHS), a nationwide biomonitoring survey. We developed a linear regression model, controlling for sex, age, smoking, and survey cycle, and obtained resulting residuals. Then, we computed the fraction of exceeding the third quartile (Q3) level of residuals for each occupation, which is employed as a relative exposure indicator across occupations.

RESULTS

A total of 15 125 measurements derived from three cycles of KoNEHS were used for analysis. The overall geometric means (GMs) and geometric standard deviation (GSD) of urine 1-OHP levels were 0.16 µg g-1 creatinine and 3.07, respectively. Among the sub-major occupational groups, 'construction and mining related elementary occupations' showed the highest fraction (0.45) of exceeding the Q3 level of residuals. Among the minor occupational groups, 'deliverers' showed a high fraction (0.42) of exceeding the Q3 level of residuals, which indicates rapidly growing occupations to be addressed.

CONCLUSIONS

Our results provide ancillary information regarding PAH exposure across occupations, especially for occupations for which PAH exposure has not been well characterized.

Phthalate metabolites in urine of children and adolescents in Germany. Human biomonitoring results of the German Environmental Survey GerES V, 2014-2017

During the population representative German Environmental Survey of Children and Adolescents (GerES V, 2014-2017) 2256 first-morning void urine samples from 3 to 17 years old children and adolescents were analysed for 21 metabolites of 11 different phthalates (di-methyl phthalate (DMP), di-ethyl phthalate (DEP), butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), di-cyclohexyl phthalate (DCHP), di-n-pentyl phthalate (DnPeP), di-(2-ethylhexyl) phthalate (DEHP), di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP) and di-n-octyl phthalate (DnOP)). Metabolites of DMP, DEP, BBzP, DiBP, DnBP, DEHP, DiNP and DiDP were found in 97%-100% of the participants, DCHP and DnPeP in 6%, and DnOP in none of the urine samples. Geometric means (GM) were highest for metabolites of DiBP (MiBP: 26.1 μg/L), DEP (MEP: 25.8 μg/L), DnBP (MnBP: 20.9 μg/L), and DEHP (cx-MEPP: 11.9 μg/L). For all phthalates but DEP, GMs were consistently higher in the 3-5 years old children than in the 14-17 years old adolescents. For DEHP, the age differences were most pronounced. All detectable phthalate biomarker concentrations were positively associated with the levels of the respective phthalate in house dust. In GerES V we found considerably lower phthalate biomarker levels than in the preceding GerES IV (2003-2006). GMs of biomarker levels in GerES V were only 18% (BBzP), 23% (MnBP), 23% (DEHP), 29% (MiBP) and 57% (DiNP) of those measured a decade earlier in GerES IV. However, some children and adolescents still exceeded health-based guidance values in the current GerES V. 0.38% of the participants had levels of DnBP, 0.08% levels of DEHP and 0.007% levels of DiNP which were higher than the respective health-based guidance values. Accordingly, for these persons an impact on health cannot be excluded with sufficient certainty. The ongoing and substantial exposure of vulnerable children and adolescents to many phthalates confirms the need of a continued monitoring of established phthalates, whether regulated or not, as well as of potential substitutes. With this biomonitoring approach we provide a picture of current individual and cumulative exposure developments and body burdens to phthalates, thus providing support for timely and effective chemicals policies and legislation.

Biomonitoring of the adult population in the area of turin waste incinerator: Baseline levels of polycyclic aromatic hydrocarbon metabolites

Exposure to polycyclic aromatic hydrocarbons (PAHs) was assessed in a cohort of 394 subjects, 198 residing in three small municipalities near a new waste-to-energy (WTE) incinerator located in the Turin area, and 196 residing in neighbouring control areas in the town (of Turin). The assessment of exposure to PAHs was part of a human biomonitoring study aimed at assessing potential incremental exposure to pollutants related to incineration activities through the analysis of such pollutants before the plant start-up, and after one and three years of operation. The exposure assessment described in this study was carried out before the start-up of the WTE incinerator. Ten monohydroxy-PAHs (OH-PAHs) were analyzed in urine samples, consisting in the principal metabolites of naphthalene (NAP), fluorene (FLU), phenanthrene (PHE), and pyrene (PYR). Concentrations of the sum of OH-PAHs (Σ₁₀OH-PAHs) were in the range of 525-85200 ng/g creatinine, with P₅₀ equal to 6770 ng/g creatinine. Metabolites of naphthalene were found at the highest concentrations (P₅₀ values of 892 and 4300 ng/g creatinine for 1- and 2-OH-NAP, respectively) followed by the three OH-FLUs (P₅₀ values of individual compounds in the range of 58.2-491 ng/g creatinine), the four OH-PHEs (P₅₀ values in the range of 30.5-145 ng/g creatinine), and 1-OH-PYR (P₅₀ value of 82.8 ng/g creatinine). Concentrations of 1-OH-NAP, 9-OH-FLU, 1-, 2-, 3, 4-OH-PHE, and 1-OH-PYR were significantly lower in subjects living near the WTE plant compared to those living in the town of Turin, with differences between the two groups in the range 14-31%. Smoking habits markedly influence the urinary concentrations OH-PAHs. Median concentrations of the single metabolites in smokers were from 1.4 fold (for 4-OH-PHE) to 14 fold higher (for 3-OH-FLU) than those observed in non-smokers. The heating system used also resulted to be a major contributor to PAH exposure. Concentrations of OH-PAHs were generally comparable with those observed in other industrialized countries. The profile pattern was consistent with those reported in the literature. Concentrations of OH-PAHs assessed in this study may be considered indicative of the background exposure to PAHs for adult population living in an urban and industrialized area.

Bioaccumulation of POPs in human breast milk from south of the Russian Far East and exposure risk to breastfed infants

The present study is a stage of the regular POP monitoring conducted in the framework of the Russian Federation's National Implementation Plan under the Stockholm Convention on Persistent Organic Pollutants. The POPs concentration (ΣHCH+ΣDDT+ΣPCB) in the samples ranged from 23 to 878 (with a mean of 151.4) ng/g lipid. The ranges of concentrations of OCPs (ΣHCH+ΣDDT) and PCBs were 2.8-291 and 3.2-720 ng/g lipid, respectively. The mean values of OCPs and PCBs amounted to 80.1 and 74.9 ng/g lipid, respectively. As suggested by the results of the EDI calculation, intake of PCBs is slightly high in infants. The fact that most studies have associated PCB with effects, such as development of congenital deformity, reduced immunity, lower weight, and small baby size at birth, makes it an alarming situation.

Regional variations in human chemical exposures in Canada: A case study using biomonitoring data from the Canadian Health Measures Survey for the provinces of Quebec and Ontario

The Canadian Health Measures Survey (CHMS), an ongoing national health survey conducted in two-year cycles, collects extensive biomonitoring data that is used to assess the exposure of Canadians to environmental chemicals of concern. Combining data from multiple cycles of the CHMS allows for the calculation of robust regional estimates of chemical concentrations in blood and urine. The objective of this work was to compare biomarkers of exposure to several environmental chemicals for the provinces of Quebec and Ontario, two major CHMS regions, as well as the entire CHMS (representing Canada) minus Quebec (CMQ), and the entire CHMS minus Ontario (CMO), and to interpret differences between regions. Geometric means and 95th percentiles of blood and/or urinary concentrations of 45 environmental chemicals or their metabolites for Ontario, Quebec, CMQ, and CMO were calculated by combining the two most recent cycles of data available for a chemical (cycles 1 and 2, or cycles 2 and 3) from the first three cycles of the CHMS (2007-2013). Weighted one-way ANOVA was used to test the differences between regional estimates. After applying a Bonferonni-Holm adjustment for multiple comparisons, the following measures were significantly higher in Quebec as compared to Ontario and CMQ: blood lead, urinary lead and the urinary polyaromatic hydrocarbon (PAH) metabolites, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2- hydroxyphenanthrene and 3-hydroxyphenanthrene. In Quebec compared to CMQ only, urinary 2-hydroxfluorene, 3-hydroxyfluorene, 2-hydroxynaphthalene, and 4-hydroxyphenanthrene were higher. The concentration of urinary fluoride was significantly higher in Ontario as compared to Quebec and CMO. Blood manganese and urinary fluoride were significantly lower in Quebec compared to CMQ, and blood and urinary selenium were significantly lower in Ontario compared to CMO. Regional differences in tobacco use, age of dwellings and drinking water fluoridation are among the possible contributing factors to some of the observed differences. In conclusion, this is the first study where biomonitoring data from multiple cycles of CHMS were combined in order to generate robust estimates for subsets of the Canadian population. Such assessments can contribute to a regional-level prioritization of control measures to reduce the exposure of Canadians to chemicals in their environment.

Correlates of exposure to phenols, parabens, and triclocarban in the Study of Environment, Lifestyle and Fibroids

We performed a cross-sectional analysis to identify correlates of urinary concentrations of seven phenols (bisphenols A, F, and S; 2,4-dichlorophenol; 2,5-dichlorophenol; benzophenone-3; triclosan), triclocarban, and four parabens (butyl, ethyl, methyl, and propyl). We analyzed baseline data from 766 participants in the Study of Environment, Lifestyle, and Fibroids, a prospective cohort study of 1693 Black women aged 23-34 years residing in Detroit, Michigan (2010-2012). We collected data on demographic, behavioral, and anthropometric factors via telephone interviews, clinic visits, and self-administered questionnaires. For each biomarker, we used linear regression models to estimate mean differences in log-transformed, creatinine-corrected concentrations across factors of interest. Each biomarker was detected in >50% of participants. Median creatinine-corrected concentrations were the highest for methyl paraben (116.8 μg/g creatinine), propyl paraben (16.8 μg/g creatinine), and benzophenone-3 (13.4 μg/g creatinine). Variables most strongly associated with biomarker concentrations included season of urine collection, education, and body mass index (BMI). BMI was positively associated with bisphenol A and S and triclocarban concentrations and inversely associated with butyl and methyl paraben concentrations. In this cohort of Black women, exposure to phenols, parabens, and triclocarban was prevalent and several factors were associated with biomarker concentrations.

Association of Urinary Polycyclic Aromatic Hydrocarbons and Diabetes in Korean Adults: Data from the Korean National Environmental Health Survey Cycle 2 (2012-2014)

PURPOSE

To investigate the associations between the urinary levels of polycyclic aromatic hydrocarbons (PAHs) and diabetes mellitus in Korean adults.

MATERIALS AND METHODS

We examined the data of 6478 participants aged ≥19 years from the Korean National Environmental Health Survey (KoNEHS) cycle 2 (2012-2014). The urinary levels of 1-hydroxypyrene (1-OHP), 2-naphthol (2-NAP), 1-hydroxyphenathrene (1-OHPhe), and 2-hydroxyfluorene (2-OHFlu) were measured by gas chromatography-mass spectrometry. Diabetes mellitus was defined as a self-report of physician-diagnosed diabetes mellitus or the use of oral hypoglycemics or insulin. Analyses were adjusted for sex, age, body mass index, household income, alcohol consumption, physical activity, urinary creatinine and cotinine, menopausal status, and quartiles of all other PAHs.

RESULTS

The prevalence of diabetes was 6.5% in the study population. In men, the geometric means of the 2-NAP and 2-OHFlu levels were higher in participants with diabetes mellitus than in those without diabetes mellitus [4.11 vs 3.26 μg/L (P <0.05) and 0.45 vs 0.40 μg/L (P <0.05), respectively]. In women, the geometric mean of 2-NAP levels was also higher in participants with diabetes mellitus than in those without diabetes mellitus (1.81 vs 0.56 μg/L, P <0.05), but there were no significant differences in geometric means for other PAHs. A higher odds ratio (OR) of diabetes was found in participants with the highest quartiles of urinary 2-NAP [OR 1.83, 95% confidence interval (CI) 1.29-2.60] and 2-OHFlu (OR 1.81, 95% CI 1.10-2.98) than in those with the lowest quartiles.

CONCLUSION

The urinary 2-NAP and 2-OHFlu levels were associated with diabetes mellitus in Korean adults. Further studies are needed to determine a potential causal relationship between PAH exposure and diabetes mellitus and its underlying mechanism.

Urinary 3-phenoxybenzoic acid levels and the association with thyroid hormones in adults: Korean National Environmental Health Survey 2012-2014

BACKGROUND

Owing to insecticidal activity at low doses with relatively low toxicity in humans, synthetic pyrethroids have been used widely for pest control in agricultural and domestic settings. Pyrethroids are suspected for potential endocrine disruption. However, the thyroid disrupting effects of pyrethroids, particularly in humans, is relatively underexplored.

OBJECTIVES

This study aimed to report 3-phenoxybenzoic acid (3-PBA) concentrations in urine, and assess its association with serum thyroid hormone (TH) levels in a representative adult population of Korea.

METHODS

Data obtained from representative Korean adults recruited in the Korean National Environmental Health Survey (2nd round, 2012-2014) were analyzed. Urinary 3-PBA levels were associated with serum thyroxine (T4), total triiodothyronine (T3), and thyroid-stimulating hormone (TSH) levels among the Korean adult population.

RESULTS

Urinary 3-PBA levels among Korean adults were >3 times higher than those reported in Canada and the United States. Urinary 3-PBA levels showed negative association with serum T4, and this pattern was not changed after stratification by sex. For T3, the association varied by sex and exposure levels. Male demonstrated the same inverse association between urinary 3-PBA and T3, but female did not show such association. Among adults in the lower half of urinary 3-PBA levels, the association with T3 was significant, while that among the remainder was marginal. The association with T4 remained significant on sensitivity analysis, after controlling for other urinary chemicals.

CONCLUSION

Urinary 3-PBA levels in the general Korean adult population were found to be generally higher than those of other countries, and were associated with decreased TH levels. Considering the importance of THs, the public health implications of pyrethroid insecticide exposure warrant further studies.

An overview of the current progress, challenges, and prospects of human biomonitoring and exposome studies

Human Biomonitoring (HB), the process for determining whether and to what extent chemical substances penetrated our bodies, serves as a useful tool to quantify human exposure to pollutants. In cases of nutrition and physiologic status, HB plays a critical role in the identification of excess or deficiency of essential nutrients. In pollutant HB studies, levels of substances measured in body fluids (blood, urine, and breast milk) or tissues (hair, nails or teeth) aid in the identification of potential health risks or associated adverse effects. However, even as a widespread practice in several countries, most HB studies reflect exposure to a single compound or mixtures which are measured at a single time point in lifecycle. On the other hand, throughout an individual's lifespan, the contact with different physical, chemical, and social stressors occurs at varying intensities, differing times and durations. Further, the interaction between stressors and body receptors leads to dynamic responses of the entire biological system including proteome, metabolome, transcriptome, and adductome. Bearing this in mind, a relatively new vision in exposure science, defined as the exposome, is postulated to expand the traditional practice of measuring a single exposure to one or few chemicals at one-time point to an approach that addresses measures of exposure to multiple stressors throughout the lifespan. With the exposome concept, the science of exposure advances to an Environment-Wide Association Perspective, which might exhibit a stronger relationship with good health or disease conditions for an individual (phenotype). Thus, this critical review focused on the current progress of HB and exposome investigations, anticipating some challenges, strategies, and future needs to be taken into account for designing future surveys.

Exposure to environmental pollutants and a marker of early kidney injury in the general population: Results of a nationally representative cross-sectional study based on the Korean National Environmental Health Survey (KoNEHS) 2012-2014

Exposure to environmental pollutants may lead to early kidney injury, chronic kidney disease (CKD) and end-stage renal disease (ESRD). This study investigated the early renal effects associated with exposure to endocrine-disrupting chemicals (EDCs) and heavy metals using general Korean population data. We used data from the Second Korean National Environmental Health Survey (2012-2014). As exposure markers, the concentrations of EDCs, such as triclosan (TCS), bisphenol A (BPA) and phthalate metabolites (DEHP, MnBP and MBzP), and heavy metals, such as cadmium, lead and mercury were analyzed. As an early kidney injury marker, the urinary concentration of β₂-microglobulin (β₂M) was measured. Multiple linear regression was used to analyze the relationship between environmental pollutants and β₂M. A total of 5489 people (male: 2538, female: 2951) aged 19 years and older were enrolled. The geometric mean (GM) concentration of β₂M in the total population was 1.88 μg/g creatinine (95% confidence interval (CI) 1.85-1.91). The β₂M concentrations were significantly higher in cases of female, old age, low income, and presence of a history of diabetes mellitus or hypertension. The GM concentrations of urinary TCS and cadmium were 1.16 μg/g creatinine (95% CI 1.11-1.21) and 0.57 μg/g creatinine (95% CI 0.57-0.59), respectively. TCS, DEHP, cadmium, lead, and mercury exposure was significantly positively related to urinary β₂M in the multiple regression analysis. β₂M levels increased significantly with increases in the cadmium, mercury, and lead levels (p for trend <0.0001). The higher the DEHP, MnBP, and TCS concentrations, the higher the β₂M level (p for trend <0.01). Environmental pollutants exposure significantly increased urinary β₂M levels in the general Korean population. To prevent the development of early kidney injury and CKD, it is important to reduce environmental pollutants exposure through regulatory measures, and cooperation between related bodies in both developing and developed countries.

Study Design, Rationale and Procedures for Human Biomonitoring of Hazardous Chemicals from Foods and Cooking in Korea

Objectives: A nationwide biomonitoring program identified the long-term trends of environmental exposures to hazardous chemicals in the general population and found geographical locations where body burdens of an exposed group significantly differed from those of the general population. The purpose of this study is to analyze the hazardous compounds associated with foods and cooking in the nationwide general population for evaluation of the environmental exposures and health risk factors and for the establishment of the reference levels at the national level. Methods: During 2009–2010, the National Institute of Food and Drug Safety Evaluation (NIFDS) conducted a nationwide human biomonitoring study, including a questionnaire survey and environmental exposure assessments for specific hazardous compounds from foods and cooking among the general population in South Korea. Results: A total of 2139 individuals voluntarily participated in 98 survey units in South Korea, including 889 (41.6%) men and 1250 women (58.4%). Bio-specimens (serum and urine) and questionnaires were collected from the study population. Acrylamides, heterocyclic amines (HCAs), phenols, and phthalates were analyzed from urine, and perfluorinated compounds (PFCs) and organic chloride pesticides (OCPs) were analyzed from serum samples. The information on exposure pathway and geographical locations for all participants was collected by questionnaire interviews, which included demographic characteristics, socioeconomic status, history of family diseases, conditions of the indoor and outdoor environment, lifestyles, occupational history, and food and dietary information. Conclusion: We describe the design of the study and sampling of human biospecimen procedures including bio-sample repository systems. The resources produced from this nationwide human biomonitoring study and survey will be valuable for use in future biomarkers studies and for the assessment of exposure to hazardous compounds associated with foods and cooking.

Association of exposure to multiple metals with papillary thyroid cancer risk in China

Papillary thyroid cancer (PTC) has inflicted huge threats to the health of mankind. Metal pollution could be a potential risk factor of PTC occurrence, but existing relevant epidemiological researches are limited. The current case-control study was designed to evaluate the relationships between exposure to multiple metals and the risk of PTC. A total of 262 histologically confirmed PTC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Urine samples were used as biomarkers to reflect the levels of environmental exposure to 13 metals. Conditional logistic regression models were adopted to assess the potential association. Single-metal and multi-metal models were separately conducted to evaluate the impacts of single and co-exposure to 13 metals. The increased concentration of urinary Cd, Cu, Fe, and Pb quartiles was found significant correlated with PTC risk. We also found the decreased trends of urinary Se, Zn, and Mn quartiles with the ORs for PTC. These dose-response associations between Pb and PTC were observed in the single-metal model and remained significant in the multi-metal model (OR_25-50th=1.39, OR_50-75th=3.32, OR_>75th=7.62, p for trend <0.001). Our study suggested that PTC was positively associated with urinary levels of Cd, Cu, Fe, Pb, and inversely associated with Se, Zn, and Mn. Targeted public health policies should be made to improve the environment and the recognition of potential risk factors. These findings need additional studies to confirm in other population.

Couples exposure to phthalates and its influence on in vitro fertilization outcomes

This prospective study examined the associations between the levels of eight urinary phthalate metabolites in 599 couples and in vitro fertilization (IVF) outcomes. We used log-binomial multivariate regression to estimate relative risks (RR) for the association between phthalate concentration and IVF binary outcomes (fertilization rate >50%, biochemical pregnancy, clinical pregnancy and live birth) for each woman after adjusting the model for the concentration in a male partner and each relevant confounders. RR was expressed per unit increase in log-transformed urinary metabolite concentration. The percentage of bis-2-ethylhexyl phthalate (DEHP) metabolites excreted as mono-2-ethylhexyl phthalate (MEHP) was calculated as %MEHP. Urinary MEHP in women was associated with an increased risk of biochemical pregnancy (RR = 1.35; p = 0.04), failed clinical pregnancy (RR = 1.56; p = 0.006) and live birth (RR = 1.54; p = 0.011). An increase in monoethyl phthalate was associated with a high risk of failed clinical pregnancy (RR = 1.25; p = 0.03) and live birth (RR = 1.35; p = 0.006). An increase in %MEHP was associated with an increase in the risk of biochemical pregnancy (RR = 1.55; p = 0.05), failed clinical pregnancy (RR = 1.73; p = 0.02) and live birth (RR = 1.65; p = 0.046). Our results demonstrated that exposure to some phthalates may adversely affect IVF outcomes, particularly when couples' exposure was jointly modeled, emphasizing the importance of a couple-based approach in assessing fertility outcomes. The associations between IVF outcomes and DEHP metabolites were stronger in women whose %MEHP was >75th percentile which may be due to their less efficient metabolism and excretion of DEHP and/or MEHP.

A benchmark dose study of prenatal exposure to di(2-ethylhexyl) phthalate and behavioral problems in children

INTRODUCTION

Prenatal exposure to di(2-ethylhexyl) phthalate (DEHP) has been reported to be associated with adverse effects on neurodevelopment that yield behavior syndromes in young children with an estimated median exposure lower than the currently recommended tolerable daily intake (TDI) and reference dose (RfD).

OBJECTIVES

Our aim was to derive the benchmark dose for prenatal exposure to DEHP for the neurodevelopmental health in children.

METHODS

A total of 122 mother-child pairs from the Taiwan Maternal and Infant Cohort Study were analyzed for the dose-response relationship between maternal exposure to DEHP and children's behavioral syndromes evaluated at 8 years (n = 122, 2009), 11 years (n = 96, 2012), and 14 years (n = 78, 2015) of age. We employed a multivariate regression model to assess the statistical associations between the estimated maternal average daily intake of DEHP and child's individual CBCL scores for boys and girls at each separate age, followed by a mixed model for all the children across three ages accounting for individual variations. We then employed structural equation models by combining the children's specific behavioral problem scores at different ages and obtained a simulated overall latent score in relation to maternal exposure. Based on the established dose-response relationship, we derived the benchmark dose (BMD) and the lower limit (BMDL).

RESULTS

Associations of maternal DEHP exposure (median 4.54μg/kg_bw/day) with the Child Behavior Checklist (CBCL) scores were all significant, except for somatic complaints, adjusting for child's age, gender, IQ, and family income. The BMDL, given a benchmark response of 0.10 (0.05) and a background response of 0.05, was 6.01 (2.16) μg/kg_bw/dayfor an integrated CBCL score.

CONCLUSIONS

The current TDI (RfD) of 50 (20) μg/kg_bw/day for DEHP might not protect pregnant women for their children from behavioral problems. There remains the lack of comparable toxicological data. Further investigations are needed.

Human Biological Monitoring of Mercury Through Hair Samples in China

Mercury (Hg) is a global pollutant that affects environmental and human health. Considering the high toxicity of Hg, it is required to assess the exposure of Hg in human body for appropriate risk management. In this review paper, we summarized data obtained through regional and small-scaled human biomonitoring (HBM) program for Hg in hair samples in China, which can deliver scientific data to make decisions on environmental health policy. Besides, the major conclusions got from this study and perspectives for future works through these HBM program in China were presented. To better understand the current situation of hair Hg levels in China, a well-coordinated and designed national HBM program is urgently needed considering the requirements of the Minamata Convention on Mercury for effectiveness evaluation.

The extent and predictors of phthalate exposure among couples undergoing in vitro fertilization treatment

Phthalates are chemicals used as plasticizers and solvents in many consumer products but are suspected of disrupting the endocrine system and are known for their reproductive/developmental health risks. This study examined the extent and predictors of phthalate exposure among 599 couples undergoing in vitro fertilization. A questionnaire was administered to obtain sociodemographic, health, and lifestyle data, and two spot urine samples were collected from the couples to analyze eight phthalate metabolites, cotinine (COT) as a smoking index, and creatinine to adjust for urine dilution. Seven phthalate metabolites were detected in > 94% of the urine samples, and monobenzyl phthalate (MBzP) was found in 24% of the women and 26% of their male partners. Median phthalate levels were highest for monoethyl phthalate (MEP), at 333.26 μg/l in women and 290 μg/l in male partners, and lowest for MBzP, at 1.17 μg/l in women and 1.14 μg/l in male partners. Correlation coefficients of ≥ 0.4 between the women and their male partners for the eight urinary phthalate metabolites may indicate a shared source of exposure. A multivariate regression model was used to assess the association between predictors and each urinary phthalate metabolite. Several potential predictors for the variations in specific urinary phthalate metabolites were identified, including the body mass index, age, socioeconomic status, and regional distribution for both women and their male partners but with slightly different patterns. Women with a history of breastfeeding, using bottled water for cooking and storing food in plastic bags had lower MEP (8.7%), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) (9.2%), and both mono-iso-butyl phthalate and MECPP (8.2 and 8.1%). A history of contraceptive use was associated with an increase in MECPP (8.7%), mono-(2-ethyl-5-hydroxyhexyl) phthalate (11.4%), mono-(2-ethyl-5-oxohexyl) phthalate (7.6%), and the molar sum of bis (2-ethylhexyl) phthalate metabolites (8.9%). Urinary COT levels were associated with an increase of 10-16% in all urinary metabolites in women but of only 10.5% in mono-(2-ethylhexyl) phthalate in male partners. More than 95% of the couples reported the use of cosmetics, perfumes, and personal-care products, but we were not able to find associations with urinary phthalate metabolites, perhaps due to their short half-lives. MEP levels associated with the use of household cleaning products were 11.2% higher in male partners. Our levels were generally higher than those reported elsewhere, perhaps due to different lifestyles, cultural practices, dietary habits, use of personal-care products, and governmental legislation.

A Review of Biomonitoring of Phthalate Exposures

Phthalates (diesters of phthalic acid) are widely used as plasticizers and additives in many consumer products. Laboratory animal studies have reported the endocrine-disrupting and reproductive effects of phthalates, and human exposure to this class of chemicals is a concern. Several phthalates have been recognized as substances of high concern. Human exposure to phthalates occurs mainly via dietary sources, dermal absorption, and air inhalation. Phthalates are excreted as conjugated monoesters in urine, and some phthalates, such as di-2-ethylhexyl phthalate (DEHP), undergo secondary metabolism, including oxidative transformation, prior to urinary excretion. The occurrence of phthalates and their metabolites in urine, serum, breast milk, and semen has been widely reported. Urine has been the preferred matrix in human biomonitoring studies, and concentrations on the order of several tens to hundreds of nanograms per milliliter have been reported for several phthalate metabolites. Metabolites of diethyl phthalate (DEP), dibutyl- (DBP) and diisobutyl- (DiBP) phthalates, and DEHP were the most abundant compounds measured in urine. Temporal trends in phthalate exposures varied among countries. In the United States (US), DEHP exposure has declined since 2005, whereas DiNP exposure has increased. In China, DEHP exposure has increased since 2000. For many phthalates, exposures in children are higher than those in adults. Human epidemiological studies have shown a significant association between phthalate exposures and adverse reproductive outcomes in women and men, type II diabetes and insulin resistance, overweight/obesity, allergy, and asthma. This review compiles biomonitoring studies of phthalates and exposure doses to assess health risks from phthalate exposures in populations across the globe.

The relationships between urinary phthalate metabolites, reproductive hormones and semen parameters in men attending in vitro fertilization clinic

Evidence from previous studies has shown that phthalates may play a role in male reproductive function; however, results are still inconclusive, and the mechanism remains unclear. In this study, we first assessed whether exposure to phthalates is associated with altered reproductive hormones and semen parameters in 599 men attending an in vitro fertilization clinic. Secondly, we evaluated whether reproductive hormones could play a mediating role in the association between phthalates and sperm parameters. Eight phthalate metabolites were measured in two different spot urine samples: mono‑n‑butyl phthalate, mono-isobutyl phthalate (MiBP), monoethyl phthalate (MEP), monobenzyl phthalate, and four oxidative metabolites of di‑(2‑ethylhexyl) phthalate (DEHP) [i.e., mono‑(2‑ethylhexyl) phthalate (MEHP), mono‑(2‑ethyl‑5‑hydroxyhexyl) phthalate (MEHHP), mono‑(2‑ethyl‑5‑oxohexyl) phthalate (MEOHP), and mono‑(2‑ethyl‑5‑carboxypentyl) phthalate (MECPP)]. Semen parameters (concentration, volume, motility, and morphology) and reproductive hormones, i.e., follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone, estradiol (E₂), testosterone (TEST) and prolactin (PROL) were also determined and considered the main study outcomes. Separate multivariate linear regression was used to assess associations between levels of each urinary phthalate metabolite, molar sum of DEHP metabolites (∑DEHP), percentage of MEHP to ∑DEHP (%MEHP), and each outcome (natural log-transformed). Inverse associations were observed between TEST and MiBP (β = -0.099), FSH and MEHHP (β = -0.087), and PROL and MEOHP (β = -0.102), while a positive relationship was seen between E₂ and MEP (β = 0.098). %MEHP was associated positively with FSH (β = 0.118) and LH (β = 0.099), but negatively with TEST/LH (β = -0.086) and TEST/E₂ (β = -0.109). Sperm concentration was associated positively with MECPP (β = 0.131), MEHHP (β = 0.117), MEOHP (β = 0.107) and ∑DEHP (β = 0.111), but negatively with %MEHP (β = -0.135). All p-values were <0.05. Sobel's test indicated that FSH mediated significantly up to 60% of the positive relationship between sperm concentration and MEHHP, while FSH and LH mediated respectively 15 and 12% of the inverse association between sperm concentration and %MEHP. Further research on this topic is warranted.

Urinary phthalate metabolites among children in Saudi Arabia: Occurrences, risks, and their association with oxidative stress markers

Phthalates have been used as plasticizers in numerous consumer applications and therefore, their metabolites have been detected in human urine worldwide. Despite concerns regarding their potential adverse health effects, few exposure assessments have been conducted among young populations in Middle Eastern countries. In this study, children (n = 109, aged 3-9 years) were recruited from four elementary schools in Riyadh, Saudi Arabia, in 2017, and major phthalate metabolites were measured in their urine. Their parents were asked to complete a questionnaire on their behalf to assess potential exposure sources of phthalates. In addition to 18 phthalate metabolites, malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured in urine samples by LC/MS/MS. Among the children of Saudi Arabia, urinary levels of monoisobutyl phthalate (MiBP) and monobutyl phthalate (MnBP) were higher than those reported previously in children worldwide. Monoethyl phthalate (MEP) was also detected at high levels. Several phthalate metabolites showed significant associations with the levels of MDA or 8-OHdG. Hazard quotients (HQs) derived for certain phthalates were greater than one. In particular, the HQs for di(2-ethylhexyl) phthalate (DEHP) were greater than one in 34% of the participating children. Levels of monocyclohexyl phthalate (MCHP), monoisodecyl phthalate (MiDP), mono(2-ethylhexyl) phthalate (MEHP), and mono[2-(carboxymethyl)hexyl] phthalate (MCMHP) in the urine samples were positively associated with the consumption frequency of certain foods. Very high levels of exposure to phthalates, along with positive associations with oxidative stress markers, outline the importance of follow-up investigations for identification of phthalate exposure sources and potential health implications among the young population of Saudi Arabia.

Impact of arsenic exposure on clinical biomarkers indicative of cardiovascular disease risk in Mexican women

An appropriate and precise identification of high-risk individuals to develop cardiovascular diseases (CVD) is of high importance to reduce these kinds of diseases, a major health concern worldwide. Therefore, the aim of this research was to evaluate prognostic CVD biomarkers in Mexican women exposed to inorganic arsenic via drinking water. Then, a cross-sectional study including 190 women was achieved. Urinary arsenic (UAs) levels were analyzed as exposure biomarker to that metalloid. While, plasma asymmetric dimethylarginine (ADMA), adipocyte fatty acid-binding protein (FABP4), adiponectin, and chemerin levels, hypertriglyceridemic waist (HW) phenotype, atherogenic index of plasma (AIP), and Framingham risk score (FRS) were assessed as prognostic CVD biomarkers. Mean UAs level detected in the evaluated urinary samples was 45.0 ± 40.0 μg/g creatinine. In addition, mean plasma ADMA, FABP4, chemerin and adiponectin levels were 0.68 µmol/L, 20.3 ng/mL, 12.5 μg/mL, and 255 ng/mL, correspondingly. Approximately, 54% of women participants displayed an HW phenotype. Regarding AIP and FRS values, 0.12 ± 0.15 and 7.50 ± 8.00 were found, respectively. Besides, strong and significant associations (p < 0.05) between UAs and AIP, ADMA, and FABP4 were distinguished. Also, after a multivariate analysis, the association between those variables persisted after adjustment for traditional risk factors of CVD. In conclusion, according to the results found in this research, the most sensible CVD biomarkers distinguished in this study were AIP, ADMA, and FABP4. Nevertheless, more studies are necessary to confirm the results found in this investigation.

Perspectives on trace chemical safety and chemophobia: risk communication and risk management

Safety issues regarding consumer products contaminated with trace amounts of chemicals are of great concern to consumers, with the degree of concern occasionally escalating to the psychological syndrome, chemophobia (i.e., the fear of chemicals). Hazardous substances frequently implicated in safety concerns include heavy metals (arsenic, mercury, cadmium, and lead), volatile organic compounds (VOC) such as benzene and o-toluidine, pesticides, carcinogens, radioactive substances, and endocrine disrupting chemicals (EDC) such as bisphenol A and phthalates. To improve communication of risk to society, members of academia, government, consumer organizations, and industry participated in this workshop to discuss and exchange perspectives on trace chemical safety. From the perspective of academia, integrated risk assessments need to be implemented to encompass various exposure sources and routes. The identification and investigation of new exposure-related biomarkers are also recommended to verify direct causal relationships between specific chemical exposure and effects on human health. As for regulation, governments need to establish and maintain acceptable limits for trace chemicals in products. In addition, harmonized efforts need to be undertaken among government agencies to share regulatory limits and effectively control trace chemicals in consumer products. Manufacturers need to faithfully abide by Good Manufacturing Practice (GMP) guidelines, monitor sources of contamination, and minimize these for consumer safety. To effectively resolve safety issues arising from trace chemicals exposure, collaborative efforts are needed involving academia, government, consumer organizations, and industry. Further, scientific evidence-based risk assessment is a critical approach to effectively manage trace chemical safety issues.

Exposure to phthalates in couples undergoing in vitro fertilization treatment and its association with oxidative stress and DNA damage

This prospective study of 599 couples seeking fertility treatment and who were recruited between 2015 and 2017 was conducted to (a) explore the associations between phthalate exposure and in vitro fertilization (IVF) outcomes; and (b) examine the implication of oxidative stress as a mediator of these. We measured eight phthalate metabolites in two spot urine samples; oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide, catalase (CAT), and total antioxidant capacity in follicular fluid and seminal plasma. We also examined DNA damage in sperm and granulosa cells. Couples were exposed to a broad range of phthalate compounds and seven metabolites were detected in over 94% of the urine samples, whereas monobenzyl phthalate was found in only 24% of women and 26% of men. Our results showed high levels of seven urinary phthalate metabolites (except monobenzyl phthalate) and a notable increase in many oxidative stress markers in both follicular fluid and seminal plasma. However, their associations with exposure were rather limited. Multivariate binomial regression modeling showed higher levels of follicular CAT levels reduced the probability of fertilization rate (≤ 50%) [Adjusted relative risk (RR_adj) = 0.52, p = 0.005] and unsuccessful live birth (RR_adj = 0.592, p = 0.023). We observed a 46% decrease in the probability of clinical pregnancy in association with an elevated percentage of DNA in the tail (RR_adj = 0.536, p = 0.04). There was a 32% and 22% increase in the probability of clinical pregnancy and unsuccessful live birth associated with higher levels of mono-(2-ethylhexyl) phthalate (RR_adj = 1.32, p = 0.049) and monoethyl phthalate (RR_adj = 1.22, p = 0.032) in women, respectively. In contrast, the probability of clinical pregnancy reduced by 20% with higher levels of mono-(2-ethyl-5-carboxypentyl) phthalate (RR_adj = 0.797, p = 0.037) and 19.6% with mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) (RR_adj = 0.804, p = 0.041) in men. Other oxidative stress biomarkers or urinary phthalate metabolites showed suggestive relationships with certain IVF outcomes. Lastly, our results demonstrated that elevated levels of CAT in follicular fluid might have a positive impact on fertilization rate ≥ 50% and successful live birth. CAT seems to play a potential role in mediating the relationship between the risk of poor fertilization rate and MEOHP and mono-isobutyl phthalate. Additional data are required to understand the clinical implications of oxidative stress and its contribution to the reproductive toxicity of phthalate exposure.

The pyrethroid insecticides permethrin and esfenvalerate do not disrupt testicular steroidogenesis in the rat fetus

The present study investigated the effects of maternal exposure to the widely used pyrethroid insecticides, permethrin and esfenvalerate, on fetal testicular steroidogenesis. Pregnant Sprague-Dawley rats were administered permethrin at doses of 1, 10, 50, or 100 mg/kg/day, or esfenvalerate at 0.1, 1, 7.5 or 15 mg/kg/day, by gavage, from gestation day (GD) 13 to 19. Testicular testosterone production and the expression of several key genes necessary for cholesterol and androgen synthesis and transport were assessed in GD 19 male fetuses. Dams treated with 100 mg/kg/day of permethrin or 15 mg/kg/day of esfenvalerate showed clinical signs of neurotoxicity. The highest dose of esfenvalerate also resulted in reduced maternal body weight gain throughout the treatment period. In the fetal testes, mRNA expressions of HMG-CoA synthase and reductase, SR-B1, StAR, P450scc, 3βHSD, P450 17A1, and 17βHSD were not affected by exposure to either pyrethroid. No significant change was observed in ex vivo testosterone production. In conclusion, in utero exposure to permethrin or esfenvalerate has no effect on the testosterone biosynthesis pathway in the fetal rat testis up to maternal toxic doses.

Exposure to environmental tobacco smoke in non - smoking adults in Israel: results of the second Israel biomonitoring survey

BACKGROUND

Exposure to environmental tobacco smoke (ETS) increases the risk of heart and respiratory disease, cancer, and premature mortality in non-smoking individuals. Results from the first Israel Biomonitoring Study in 2011 showed that over 60% of non-smoking adults are exposed to ETS. The purpose of the current study was to assess whether policies to restrict smoking in public places have been associated with reductions in exposure to ETS, and to examine predictors of exposure.

METHODS

We analyzed urinary cotinine and creatinine concentrations in 194 adult participants in the National Health and Nutrition (RAV MABAT) Survey in 2015-2016. Study participants were interviewed in person on smoking status and exposure to ETS. We calculated creatinine-adjusted and unadjusted urinary cotinine geometric means and medians among smokers and non-smokers. We analyzed associations in univariable analyses, between socio-demographic variables and self - reported exposure, and urinary cotinine concentrations.

RESULTS

There was no reduction in geometric mean urinary cotinine levels in non-smokers in the current study (1.7 μg/g) compared to that in 2011 (1.6 μg/g). Median cotinine levels among the non - smoking Arab participants were higher in comparison to the Jewish and other participants (2.97 versus 1.56 μg/l, p = 0.035). Participants who reported that they were exposed to ETS at home had significantly higher median levels of creatinine adjusted urinary cotinine than those reporting they were not exposed at home (4.19 μg/g versus 2.9 μg/g, p = 0.0039).

CONCLUSIONS

Despite additional restrictions on smoking in public places in 2012-2016, over 60% of non-smoking adults in Israel continue to be exposed to ETS. Urinary cotinine levels in non-smokers have not decreased compared to 2011. Results indicate higher exposure to ETS in Arab study participants and those reporting ETS exposure at home. There is an urgent need: (1) to increase enforcement on the ban on smoking in work and public places; (2) for public health educational programs and campaigns about the adverse health effects of ETS; and (3) to develop and disseminate effective interventions to promote smoke free homes. Periodic surveys using objective measures of ETS exposure (cotinine) are an important tool for monitoring progress, or lack thereof, of policies to reduce exposure to tobacco smoke in non-smokers.

Sex Differences in Neurotoxicogenetics

A major development in biomedical research is the recognition that the sex of an individual plays a key role in susceptibility, treatment, and outcomes of most diseases. In this contribution, we present evidence that sex is also important in the toxicity of many environmental toxicants and contributes to the effect of genetics. Thus, individual differences in response to toxicants includes genetic makeup, the environment and sex; in fact, sex differences may be considered a part of genetic constitution. In this review, we present evidence for sex contribution to susceptibility for a number of toxicants.

Serum Concentrations of New Predictive Cardiovascular Disease Biomarkers in Mexican Women Exposed to Lead

The purpose of this study was to evaluate lead exposure and its relationship with serum levels of predictive CVD biomarkers [asymmetric dimethylarginine (ADMA), adipocyte fatty acid-binding protein (FABP4), adiponectin, and chemerin] in women living in San Luis Potosi, Mexico. A mean blood lead level (BLL) of 11.5 ± 9.00 μg/dL (mean ± standard deviation) was found after all blood samples were analyzed. Regarding serum predictive CVD biomarkers, mean serum level of 0.68 ± 0.38 μmol/L, 20.5 ± 16.5 ng/mL, 12.5 ± 3.30 μg/mL, and 255 ± 130 ng/mL were found for ADMA, FABP4, adiponectin, and chemerin, respectively. Simple significant associations (Pearson´s correlations) between BLL and ADMA (r = 0.17; p = 0.04) and FABP4 (r = 0.23; p = 0.03) were found. Furthermore, a multivariate linear regression model showed that BLL was a significant predictor of serum ADMA (β = 0.06; p = 0.001) and FABP4 (β = 1.75; p = 0.0004) concentrations after adjusting by confounders. For serum chemerin and adiponectin levels, no associations were found with BLL. In conclusion, high serum ADMA and FABP4 (predictive CVD biomarkers) levels were found in women exposed to lead. Consequently, this research can be used as a point of departure for the prevention of CVD events in populations living in sites environmentally impacted with lead.

Exposure to lead and mercury through breastfeeding during the first month of life: A CHECK cohort study

Mercury and lead are naturally occurring toxicants and are responsible for various health issues including neurobehavioral and developmental disorders. Because of crucial synchronized developmental processes occurring at the early stage of life, infancy and childhood are considered as among the most susceptible windows to the exposure to these metals. Breastmilk is often the only source of nutrition during the first months of life. As breastmilk can be contaminated with these metals, breastfeeding may serve as a significant route of heavy metal exposure among infants. In order to understand current levels of exposure to mercury and lead through breastfeeding, and their associated risks, a total of 157 lactating mothers were recruited from Children's Health and Environmental Chemicals of Korea (CHECK) cohort, and breastmilk samples were collected at 15 and 30days after delivery (n=207). Mercury was detected from 100% of breastmilk with a median concentration of 0.59μg/L, and lead was detected in 77% of the samples with a median at 4.71μg/L. Higher concentrations of lead were found in the 30- day breastmilk than in the 15-day. Up to 45% of the breastmilk samples exceeded the normal range of the breastmilk lead suggested by WHO. Based on Monte Carlo simulation, about 71% of 15days old infants and 56% of 30days old infants were estimated at risk due to lead exposure through breastfeeding. Considering vulnerability of infants and well-known neurological toxicity of these metals, further studies to identify major exposure sources that contribute the lead concentration in breastmilk and health implication of early life stage exposure to lead among the breastfed infants are warranted.

Lead, Mercury, and Cadmium Exposure in the Korean General Population

BACKGROUND

Lead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population.

METHODS

This population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0-83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer.

RESULTS

The geometric mean, median and 95th percentile of blood Pb was 1.82 μg/dL, 1.83 μg/dL, and 3.78 μg/dL, respectively. The respective values were 2.92 μg/L, 2.87 μg/L, 9.12 μg/L for Hg, and 0.56 μg/L, 0.59 μg/L, 2.20 μg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0-4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age.

CONCLUSION

This study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.

Human biomonitoring of eight trace elements in urine of residents living in rural areas along the Yangtze River, China

The rapid economic development and industrialization have made heavy metal contamination a great public concern, especially in China. However, the levels of heavy metals in human body, especially those susceptible to the effect of industrial progression, are rarely explored. In this study, eight elements in 2643 urinary samples of individuals living in rural areas along the Yangtze River were determined through inductively coupled plasma optical emission spectrometry (As, Cr, Cu, Fe, Mn, Pb, and Zn) and TAS-990 atomic absorption spectrophotometry (Cd). Two-level regression model was applied to explore the potential factors associated with the level of the eight trace elements. After adjusting for urinary creatinine, the geometric means were 77.5, 10.98, 14.39, 13.00, 0.59, 1.51, 489.62, and 1.80 μg/g for As, Cr, Cu, Fe, Mn, Pb, Zn, and Cd, respectively. The level of eight elements varied among individual and familial characteristics. Compared with domestic and international results, the rural residents living in riverside areas had higher level of As, Cd, Cr, Fe, and Zn. Therefore, industrial progression followed by economic development has resulted in high body burden of heavy metals. Targeted public health policies should be made to improve the local environment and the recognition of potential risk factors.

Selected Organochlorines in Human Blood and Urine in the South of the Russian Far East

The trace OCP concentrations, such as α-, β-, and γ-HCH, DDT and its metabolites (DDD and DDE) in blood and urine of residents from the south of the Russian Far East was revealed. A large range of OCPs was found in the urine: α- and γ-isomers of HCH, DDT and DDE. The only β-HCH was detected in the blood; this indicates its persistence and the difficulty of excretion this substance from the organism. The total trace OCP concentration, found in the biological fluids of residents of the south of the Russian Far East, providing further evidence that these organic contaminants persist in the environment.

Hemoglobin Adducts and Urinary Metabolites of Arylamines and Nitroarenes

Arylamines and nitroarenes are intermediates in the production of pharmaceuticals, dyes, pesticides, and plastics and are important environmental and occupational pollutants. N-Hydroxyarylamines are the toxic common intermediates of arylamines and nitroarenes. N-Hydroxyarylamines and their derivatives can form adducts with hemoglobin (Hb-adducts), albumin, DNA, and tissue proteins in a dose-dependent manner. Most of the arylamine Hb-adducts are labile and undergo hydrolysis in vitro, by mild acid or base, to form the arylamines. According to current knowledge of arylamine adduct-formation, the hydrolyzable fraction is derived from the reaction products of the arylnitroso derivatives that yield arylsulfinamide adducts with cysteine. Hb-adducts are markers for the bioavailability of N-hydroxyarylamines. Hb-adducts of arylamines and nitroarenes have been used for many biomonitoring studies for over 30 years. Hb-adducts reflect the exposure history of the last four months. Biomonitoring of urinary metabolites is a less invasive process than biomonitoring blood protein adducts, and urinary metabolites have served as short-lived biomarkers of exposure to these hazardous chemicals. However, in case of intermittent exposure, urinary metabolites may not be detected, and subjects may be misclassified as nonexposed. Arylamines and nitroarenes and/or their metabolites have been measured in urine, especially to monitor the exposure of workers. This review summarizes the results of human biomonitoring studies involving urinary metabolites and Hb-adducts of arylamines and nitroarenes. In addition, studies about the relationship between Hb-adducts and diseases are summarized.