Halogenated POPs and PAHs in blood plasma of Hong Kong residents

Exposure biomarker profiles of polycyclic aromatic hydrocarbons based on a rat model using a versatile analytical framework

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic toxic pollutants. Parent PAHs (pPAHs) are mainly metabolized into mono-hydroxylated PAHs (OH-PAHs) after entering the human body. Until now, it is still an urgent need to select appropriate exposure biomarkers for PAHs and analyze them at the trace level. Based on gas chromatography coupled with triple-quadrupole tandem mass spectrometry, we have developed a versatile analytical method for the systemic analysis of pPAHs and OH-PAHs in routinely collected biological samples. This method was further applied to analyze plasma, hair and urine samples from 24 rats exposed to 13 pPAH congeners at four levels. The detection rate for pPAHs in three types of samples was 100%, except for dibenz(a,h)anthracene (DahA) in plasma, while the detection rate for OH-PAHs ranged from 25% to 100%. A significant linear relationship was observed between pPAH exposure levels and their corresponding OH-PAH levels in three different types of samples. It was found that each unit increase in pPAH exposure level was associated with an increase in OH-PAHs ranging from 0.03% (0.01-0.05%) to 5.27% (1.74-8.81%). Furthermore, significant positive correlations were found between any two types of samples for most OH-PAHs, but not observed for most pPAHs. The correlation patterns of 1-hydroxypyrene (1-OH-PYR) across three types of samples differed from other congeners. Strong correlations were identified between five types of hydroxyphenanthrene (OH-PHE) and pPAH exposure levels. In conclusion, OH-PAHs were more sensitive exposure biomarkers than pPAHs, particularly in hair and urine samples.

An exposome atlas of serum reveals the risk of chronic diseases in the Chinese population

Although adverse environmental exposures are considered a major cause of chronic diseases, current studies provide limited information on real-world chemical exposures and related risks. For this study, we collected serum samples from 5696 healthy people and patients, including those with 12 chronic diseases, in China and completed serum biomonitoring including 267 chemicals via gas and liquid chromatography-tandem mass spectrometry. Seventy-four highly frequently detected exposures were used for exposure characterization and risk analysis. The results show that region is the most critical factor influencing human exposure levels, followed by age. Organochlorine pesticides and perfluoroalkyl substances are associated with multiple chronic diseases, and some of them exceed safe ranges. Multi-exposure models reveal significant risk effects of exposure on hyperlipidemia, metabolic syndrome and hyperuricemia. Overall, this study provides a comprehensive human serum exposome atlas and disease risk information, which can guide subsequent in-depth cause-and-effect studies between environmental exposures and human health.

Parent and halogenated polycyclic aromatic hydrocarbons exposure in aluminum smelter workers: Serum levels, accumulation trends, and association with health indicators

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs) can be unintentionally formed and released during industrial thermal processes. However, information on internal exposure and health risks of PAHs and HPAHs for thermal industry workers is very limited. In this study, serum samples from 220 aluminum smelter workers in East China were analyzed, and the relationship between the levels of these pollutants and various health indicators was also assessed. The workers had markedly higher serum concentrations of PAHs and HPAHs than the controls. The serum concentrations of ∑13PAHs and ∑9HPAHs increased with increasing age and occupational exposure duration in male workers. A positive correlation was observed between the ∑13PAH and ∑9HPAH serum concentrations, and the concentration of ∑13PAHs was approximately 50 times higher than that of ∑9HPAHs. For benzo[a]pyrene equivalent (BaPeq)-based risk assessment, the contribution of PAHs and HPAHs to the risk was 80 % and 20 % in the workers. PAHs and HPAHs showed a positive association with pulmonary hypofunction, hypertension and abnormal electrocardiogram. This study indicates occupational exposure to these toxic pollutants remains a significant issue and provides evidence that elevated serum levels of ∑13PAHs and ∑9HPAHs may be associated with an increased risk of lung and cardiovascular diseases.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study, 2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL values of women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study found that exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Organochlorine pesticides and polycyclic aromatic hydrocarbons in serum of Beijing population: Exposure and health risk assessment

Organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, but large-scale human biomonitoring and health risk assessment data on these contaminants remain limited. In this study, concentrations of 6 OCPs and 5 PAHs were determined by GC-MS/MS in 1268 human serum samples which were collected from the participants in 2017 Beijing Chronic Disease and Risk Factor Surveillance. The detection frequencies of OCPs and PAHs ranged from 64.7 % to 96.5 % and 89.4 % to 99.6 %, respectively. The most abundant contaminants in OCPs and PAHs were pentachlorophenol (PCP) and pyrene (Pyr) with median concentrations reaching up to 3.13 and 8.48 μg/L, respectively. Nonparametric tests were employed to assess the correlations among contaminants levels, demographic characteristics (age, gender, body mass index, residence) and serum biochemical indexes. Significantly higher serum levels of all PAHs were observed in suburb residents than that in urban residents (P < 0.001). Binary logistic regression analysis demonstrated that exposure to benzo(a)pyrene (OR 2.17 [1.29, 3.63]), phenanthrene (OR 1.06 [1.02, 1.11]), fluoranthene (OR 1.04 [1.02, 1.07]) and Pyr (OR 1.02 [1.01, 1.03]) might increase the occurrence of hyperglycemia, and exposure to hexachlorobenzene (HCB) (OR 1.53 [1.05, 2.22]) and pentachlorobenzene (OR 1.14 [1.02, 1.27]) were positively associated with hyperlipidemia. Furthermore, the hazard quotients (HQs) for serum HCB, PCP and p,p'-dichlorodiphenyldichloroethylene were calculated based on health-based guidance values to predict health risks. 0.2 % and 4.3 % of serum samples showed HQ values exceeding 1 for HCB and PCP, respectively, in case of the non-carcinogenic risk, while 23.1 % of HQs for HCB were above 1 in case of the carcinogenic risk for a risk level 10^-5. Our study reveals that the body burden of the Beijing general population relative to OCPs and PAHs was nonnegligible. The past exposure of HCB and PCP might adversely affect the health status of the Beijing population.

Accumulative levels, temporal and spatial distribution of common chemical pollutants in the blood of Chinese adults

China has been in a rapid development period in recent decades, the mass production and use of chemical industrial products and pesticides have resulted in a large amount of pollutants in the environment. These pollutants enter the human body through environmental exposure and dietary intake, causing adverse health effects. Although many of them have been banned and restricted in the production and use in China, these pollutants still remain in the human body due to their high persistence and strong bioaccumulation. In this review, we aim to reveal the accumulation levels and profiles, as well as the temporal and spatial distribution of common chemical pollutants including chlorinated paraffins (CPs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers, organophosphorus flame retardants (OPFRs), new halogenated flame retardants (NHFRs), polychlorinated biphenyls, phthalic acid esters, perfluorinated compounds, bisphenols, organophosphorus pesticides and pyrethroid insecticides in the blood (including whole blood, serum and plasma) of Chinese adults by extracting 93 related studies published from 1990 to 2021. Results have shown that CPs, OCPs and PAHs were the main pollutants in China, the levels of short-chain chlorinated paraffin, p,p'-DDE and phenanthrene in blood even reached 11,060.58, 740.41 and 498.28 ng/g lipid respectively. Under the strict control of pollutants in China, the levels of most pollutants have been on a downward trend except for perfluoro octanoate and perfluoro nonanoate. Besides, OPFRs, NHFRs and PAHs may have a potential upward trend, requiring further research and observation. As for spatial distribution, East China (Bohai Bay and Yangtze River Delta) and South China (Pearl River Delta) were the major polluted regions due to their fast development of industry and agriculture.

Parent and Halogenated Polycyclic Aromatic Hydrocarbons in the Serum of Coal-Fired Power Plant Workers: Levels, Sex Differences, Accumulation Trends, and Risks

Workers in coal-fired power plants are at a high risk of exposure to polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs), yet no studies have investigated such exposure of HPAHs. In this study, 12 PAHs and 8 chlorinated PAHs, but no brominated PAHs, were detected in >80% of serum samples from workers of a coal-fired power plant in eastern China. Serum HPAH concentrations were higher in plant workers (16-273 ng/g lipid) than in people without occupational exposure (12-51 ng/g lipid), and serum PAH and HPAH concentrations both in male and female workers were positively correlated with the occupational exposure duration, with an estimated doubling time of 11-17 years. Correlations were found between concentrations of ∑₈HPAHs and ∑₁₂PAHs but not between 7-chlorobenz[a]anthracene (7-ClBaA) and 1-chloropyrene (1-ClPyr) and their respective parent PAHs. In males, total concentrations of PAHs and HPAHs were positively correlated with pulmonary hypofunction and hypertension but not with abnormal electrocardiogram. The benzo[a]pyrene equivalents ratio of ∑₈HPAHs/∑₁₂PAHs was 0.3 ± 0.1. Among the HPAHs in the serum, 9-chlorophenanthrene, 7-ClBaA, and 1-ClPyr showed high health risks. This study is the first report on HPAH exposure in coal-fired power plant workers and provides new evidence on the health risks of PAHs and HPAHs in humans.

In vitro airway models from mice, rhesus macaques, and humans maintain species differences in xenobiotic metabolism and cellular responses to naphthalene

The translational value of high-throughput toxicity testing will depend on pharmacokinetic validation. Yet, popular in vitro airway epithelia models were optimized for structure and mucociliary function without considering the bioactivation or detoxification capabilities of lung-specific enzymes. This study evaluated xenobiotic metabolism maintenance within differentiated air-liquid interface (ALI) airway epithelial cell cultures (human bronchial; human, rhesus, and mouse tracheal), isolated airway epithelial cells (human, rhesus, and mouse tracheal; rhesus bronchial), and ex vivo microdissected airways (rhesus and mouse) by measuring gene expression, glutathione content, and naphthalene metabolism. Glutathione levels and detoxification gene transcripts were measured after 1-h exposure to 80 µM naphthalene (a bioactivated toxicant) or reactive naphthoquinone metabolites. Glutathione and glutathione-related enzyme transcript levels were maintained in ALI cultures from all species relative to source tissues, while cytochrome P450 monooxygenase gene expression declined. Notable species differences among the models included a 40-fold lower total glutathione content for mouse ALI trachea cells relative to human and rhesus; a higher rate of naphthalene metabolism in mouse ALI cultures for naphthalene-glutathione formation (100-fold over rhesus) and naphthalene-dihydrodiol production (10-fold over human); and opposite effects of 1,2-naphthoquinone exposure in some models-glutathione was depleted in rhesus tissue but rose in mouse ALI samples. The responses of an immortalized bronchial cell line to naphthalene and naphthoquinones were inconsistent with those of human ALI cultures. These findings of preserved species differences and the altered balance of phase I and phase II xenobiotic metabolism among the characterized in vitro models should be considered for future pulmonary toxicity testing.

Exposure levels of PCDD/Fs and PCBs in human blood and the transplacental transfer characteristics in cord blood of newborns near the industrialized area

Mono-to octa-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in pooled blood from the general population living near a typical industrialized area were investigated. Less chlorinated PCDD/Fs (mean: 2602 pg L^-1) were 7.5 times those of highly chlorinated ones (mean: 349 pg L^-1). The average ΣPCBs and Σdl-PCBs concentrations in human (cord) blood were 2741 (117) and 18 (0.31) ng L^-1, respectively. Higher concentrations of highly chlorinated PCDD/Fs were found in females than in males across different ages. The mean concentrations (and toxic equivalents (TEQs)) of PCDD/Fs were 282 (27) pg L^-1 in males and 312 (32) pg L^-1 in females. The concentrations of the PCDD/Fs and PCBs increased with age for both males and females, which might be caused by the long half-lives of these compounds and decreases in metabolic rates with age as the metabolic of nutrients, food, and also PCDD/Fs and PCBs would trend to slow. The TEQ of total PCDD/Fs and PCBs was higher in blood from orthopedics patients (107 pg L^-1) than other patients. This result may be associated with the bone density and pollutant bioaccumulation. In addition, total concentration of PCDD/Fs and PCBs in blood of women at reproductive age were 6.6 and 37 times the cord blood of newborns, respectively. Positive correlation of PCDD/Fs and PCBs especially for the higher chlorinated compounds between female and cord blood were discovered, which might be caused by the transplacental transfer characteristics and blood barrier for macromolecules and reduce the chemical exposure risks for newborns.

Insights into the hepatotoxicity of pyrene and 1-chloropyrene using an integrated approach of metabolomics and transcriptomics

The toxicity of pyrene (Pyr) and its chlorinated species have not be comprehensively and clearly elucidated. In this study, an integrated approach of metabolomics and transcriptomics were applied to evaluate the hepatotoxicity of Pyr and 1-chloropyrene (1-Cl-Pyr) at human exposure level, using human L02 hepatocytes. After 24 h exposure to Pyr and 1-Cl-Pyr at 5-500 nM, cell viability was not significantly changed. Transcriptomics results showed that exposure to Pyr and 1-Cl-Pyr at 5 and 50 nM obviously altered the gene expression profiles, but did not significantly induce the expression of genes strongly related to the activation of aryl hydrocarbon receptor (AhR), such as CYP1A1, CYP1B1, AHR, ARNT. Pyr and 1-Cl-Pyr both induced a notable metabolic perturbation to L02 cells. Glycerophospholipid metabolism was found to be the most significantly perturbed pathway after exposure to Pyr and 1-Cl-Pyr, indicating their potential damage to the cell membrane. The other significantly perturbed pathways were identified to be oxidative phosphorylation (OXPHOS), glycolysis, and fatty acid β oxidation, all of which are related to energy production. Exposure to Pyr at 5 and 50 nM induced the up-regulation of fatty acid β oxidation and OXPHOS. The similar result was observed after exposure to 5 nM 1-Cl-Pyr. In contrast, exposure to 50 nM 1-Cl-Pyr induced the down-regulation of OXPHOS by inhibiting the activity of complex I. The obtained results suggested that the modes of action of Pyr and 1-Cl-Pyr on energy production remarkably varied not only with molecular structure change but also with exposure concentration.

Simultaneous determination of 35 organochlorine pesticides and polychlorinated biphenyls in the serum of the general population in Wuhan by solid phase extraction-gas chromatography-tandem mass spectrometry

有机氯农药(OCPs)和多氯联苯(PCBs)是两类重要的持久性有机污染物,可在环境介质中长期存在,并通过多种途径进入人体,导致人体的高暴露风险。OCPs和PCBs对人体存在诸多健康危害,精准定量人体内OCPs和PCBs的暴露水平是健康效应评价的关键。该研究基于固相萃取-气相色谱-串联质谱联用技术(SPE-GC-MS/MS)建立了同时检测100 μL血清中35种OCPs和PCBs的分析方法。血清样品经尿素沉淀蛋白后,采用Oasis^® HLB小柱净化,正己烷-二氯甲烷混合溶液(1∶1, v/v)洗脱,氮吹近干,正己烷定容,多反应监测(MRM)模式检测,内标法定量分析。结果表明,OCPs和PCBs在0.05~50.0 ng/mL范围内线性关系良好,检出限在1.2~71.4 ng/L之间。35种目标分析物的加标回收率在72.6%~142%之间,相对标准偏差小于25%。利用所建立的方法检测了武汉市普通人群血清样本中OCPs和PCBs的浓度水平,结果表明武汉市普通人群广泛暴露于OCPs和PCBs,且以OCPs为主。有8种OCPs和7种PCBs检出率高于50%,其中p,p'-滴滴伊、p,p'-滴滴滴和甲氧滴滴涕检出率达100%,非类二噁英PCBs是PCBs的主要成分。血清中OCPs浓度随年龄增长呈升高趋势,在60岁以上存在性别差异;不同性别、年龄人群血清中PCBs浓度无统计学差异。该方法样本用量少,操作简便,具有较高的准确度和精密度,适用于环境健康研究中大量人群血清样本中痕量OCPs和PCBs的生物监测。

Effect of Affinity between Dechlorane Plus and Human Serum Albumin on Its Serum Concentration in a General Population

Dechlorane Plus (DP) has been detected in human serum around the world. Determining how DP binds to human serum albumin (HSA) could improve our understanding of the effects of DP in humans. The results of a fluorescence titration experiment indicated that DP binds to HSA at the interface between domains IIA and IIB, and HSA has more affinity for anti-DP than syn-DP. The DP concentrations in serum from 33 people living in Wuxi City, China, were determined in five consecutive years (2012-2016). The total concentrations of the two DP isomers were 1.73-16.3 ng·g^-1 lipid weight (mean 4.7 ng·g^-1 lipid weight). No clear increasing or decreasing temporal trend was found in the DP concentrations in serum over the study period. The affinity between DP and HSA will increase as the amount of fatty acids combined with HSA increases. This explained the syn-DP and anti-DP concentrations in serum being higher for overweight people than for normal weight people. Ethanol can occupy the DP binding sites on HSA. This explained the syn-DP and anti-DP concentrations being lower for alcoholic people than for nonalcoholic people.

Polycyclic aromatic hydrocarbons in bone homeostasis

Prolonged exposure to polycyclic aromatic hydrocarbons (PAHs) may result in autoimmune diseases, such as rheumatoid arthritis (RA) and osteoporosis (OP), which are based on an imbalance in bone homeostasis. These diseases are characterized by bone erosion and even a disruption in homeostasis, including in osteoblasts and osteoclasts. Current evidence indicates that multiple factors affect the progression of bone homeostasis, such as genetic susceptibility and epigenetic modifications. However, environmental factors, especially PAHs from various sources, have been shown to play an increasingly prominent role in the progression of bone homeostasis. Hence, it is essential to investigate the effects and pathogenesis of PAHs in bone homeostasis. In this review, recent progress is summarized concerning the effects and mechanisms of PAHs and their ligands and receptors in bone homeostasis. Moreover, strategies based on the effects and mechanisms of PAHs in the regulation of the bone balance and alleviation of bone destruction are also reviewed. We further discuss the future challenges and perspectives regarding the roles of PAHs in autoimmune diseases based on bone homeostasis.

Human health risks estimations from polycyclic aromatic hydrocarbons in serum and their hydroxylated metabolites in paired urine samples

Polycyclic aromatic hydrocarbons (PAHs) are compounds with two or more benzene rings whose hydroxylated metabolites (OH-PAHs) are excreted in urine. Human PAH exposure is therefore commonly estimated based on urinary OH-PAH concentrations. However, no study has compared PAH exposure estimates based on urinary OH-PAHs to measurements of PAH levels in blood samples. Estimates of PAH exposure based solely on urinary OH-PAHs may thus be subject to substantial error. To test this hypothesis, paired measurements of parent PAHs in serum and OH-PAHs in urine samples from 480 participants in Guangzhou, a typical developed city in southern China, were used to investigate differences in the estimates of human PAH exposure obtained by sampling different biological matrices. The median PAH concentration in serum was 4.05 ng mL^-1, which was lower than that of OH-PAHs in urine (8.33 ng mL^-1). However, serum pyrene levels were significantly higher than urinary levels of its metabolite 1-hydroxypyrene. Concentrations of parent PAHs in serum were not significantly correlated with those of their metabolites in urine with the exception of phenanthrene, which exhibited a significant negative correlation. Over 28% of the participants had carcinogenic risk values above the acceptable cancer risk level of 10^-6. Overall, estimated human exposure and health risks based on urinary 1-hydroxypyrene levels were only 13.6% of those based on serum pyrene measurements, indicating that estimates based solely on urine sampling may substantially understate health risks due to PAH exposure.

Validation of exposure indexes to pesticides through the analysis of exposure and effect biomarkers in ground pesticide applicators from Argentina

The characterization of the population exposed to pesticides and the use of effective biomarkers to evaluate potential health effects are determinant to identify vulnerable groups, understanding the causality of diverse pathologies and propose prevention policies. This is particularly important in countries where intensive agricultural practices had an explosive expansion in last decades. The aim of this study was assessing the usefulness of two exposure indexes questionnaire-based: Intensity Level of the pesticide Exposure (ILE) and Cumulative Exposure Index (CEI) and their scales, in terrestrial applicators of pesticide from the Province of Córdoba (Argentina). The analysis was performed contrasting ILE and CEI results with perceived symptomatology, in addition to effect and exposure biomarkers. A cross-sectional study was designed to compare pesticides body burdens and effect biomarkers between subjects occupationally (OE) and non-occupationally exposed (NOE) to pesticides. Prevalence of perceived symptomatology and genotoxicity damage was higher in the OE group. The exposure condition was the only variable explaining these differences. Significant associations were found between CEI and neurologic symptomatology (p < 0.05) and between ILE and plasmatic cholinesterase (p < 0.1). However, residues of HCB, β-HCH, α-endosulfan, pp'DDE, endrin, β-endosulfan, pp'DDT, endosulfan sulfate and mirex were found in blood samples from both groups. To our knowledge, this is the first report on pesticides body burdens in occupational exposure settings in Argentina. So far, our current results indicate that the occupational condition affects the health of the workers. Significant associations found between symptomatology and biomarkers with scales of CEI and ILE suggest their usefulness to verify different levels of exposure. Further research is necessary to propose these indexes as an affordable tool for occupational health surveillance in areas with difficult access to health care centres.

Heart Failure and PAHs, OHPAHs, and Trace Elements Levels in Human Serum: Results from a Preliminary Pilot Study in Greek Population and the Possible Impact of Air Pollution

Cardiovascular diseases (CVDs) have been associated with environmental pollutants. The scope of this study is to assess any potential relation of polycyclic aromatic hydrocarbons (PAHs), their hydroxylated derivatives, and trace elements with heart failure via their direct determination in human serum of Greek citizens residing in different areas. Therefore, we analyzed 131 samples including cases (heart failure patients) and controls (healthy donors), and the respective demographic data were collected. Significantly higher concentrations (p < 0.05) were observed in cases' serum regarding most of the examined PAHs and their derivatives with phenanthrene, fluorene, and fluoranthene being the most abundant (median of >50 μg L-1). Among the examined trace elements, As, Cd, Cu, Hg, Ni, and Pb were measured at statistically higher concentrations (p < 0.05) in cases' samples, with only Cr being significantly higher in controls. The potential impact of environmental factors such as smoking and area of residence has been evaluated. Specific PAHs and trace elements could be possibly related with heart failure development. Atmospheric degradation and smoking habit appeared to have a significant impact on the analytes' serum concentrations. PCA-logistic regression analysis could possibly reveal common mechanisms among the analytes enhancing the hypothesis that they may pose a significant risk for CVD development.

A two-step gas chromatography-tandem mass spectrometry method for measurement of multiple environmental pollutants in human plasma

Individuals are exposed to a wide variety of chemicals over their lifetime, yet current understanding of mixture toxicology is still limited. We present a two-step analytical method using a gas chromatograph-triple quadrupole mass spectrometer that requires less than 1 mL of sample. The method is applied to 183 plasma samples from a study population of children with autism spectrum disorder, their parents, and unrelated neurotypical children. We selected 156 environmental chemical compounds and ruled out chemicals with detection rates less than 20% of our study cohort (n = 61), as well as ones not amenable to the selected extraction and analytical methods (n = 34). The targeted method then focused on remaining chemicals (n = 61) plus 8 additional polychlorinated biphenyls (PCBs). Persistent pollutants, such as p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and PCB congeners 118 and 180, were detected at high frequencies and several previously unreported chemicals, including 2,4,6-trichlorophenol, isosafrole, and hexachlorobutadiene, were frequently detected in our study cohort. This work highlights the benefits of employing a multi-step analytical method in exposure studies and demonstrates the efficacy of such methods for reporting novel information on previously unstudied pollutant exposures.

Tissue distribution, bioaccumulation, and carcinogenic risk of polycyclic aromatic hydrocarbons in aquatic organisms from Lake Chaohu, China

Freshwater products consumed in the diet are among the major sources of exposure of humans to polycyclic aromatic hydrocarbons (PAHs). In this study, eight freshwater organisms and environmental samples were collected from Chaohu Lake, the fifth-largest lake in China. The levels of PAHs in the collected organisms were measured using GC-MS. Tissue distribution characteristics in three fish species were studied. Relationship between residual levels and environment concentrations were analyzed and bioaccumulation effect and influencing factors were identified. Finally, the potential carcinogenic risk of aquatic product intake was estimated. The concentrations of ΣPAHs in aquatic organisms varied from 18.4 to 398 ng/g, with a mean value of 157 ± 125 ng/g. For carp, the highest ΣPAHs level was detected in the brain with concentration of 591 ng/g. For topmouth culter, and bighead fish, the organs with the greatest ΣPAHs concentration were gills (440 ng/g) and muscles (200 ng/g), respectively. Significant correlations were found between the PAH content in environment media including water, SPM, sediment and PAH content in aquatic animals. The calculation of food web magnification factors and risk assessment indicates that although the PAH concentration diluted with the increase of the trophic level, PAHs exposure through the aquatic products intake still poses potential carcinogenic risk. The incremental lifetime cancer risk values were 7.68 × 10^-6 and 4.75 × 10^-6 in urban and rural populations, respectively.

Efficient Detection and Removal of Polycyclic Aromatic Hydrocarbons Using Cyclodextrin-Modified Cellulose

Covalent functionalization of cellulose with β-cyclodextrin by succinic acid-promoted cross-linking leads to a dual-function material that efficiently promotes proximity-induced energy transfer from polycyclic aromatic hydrocarbons (PAHs) to squaraine fluorophores with high quantum yields, and removes PAHs from aqueous solution through non-covalent binding. This material, which possesses a high functionalization density (0.17 μg/mm² of cyclodextrin on cellulose), promotes energy transfer efficiencies as high as 58 % (for an anthracene donor in combination with a squaraine fluorophore acceptor), and leads to the removal of up to 91 % of a PAH (pyrene) from aqueous solution by mixing of the solution with the functionalized material. Overall, the high performance of this material in both proximity-induced energy transfer and the removal of PAHs from water means that such a method has significant potential impact in a variety of real-world environmental remediation scenarios.

Exposure to polycyclic aromatic hydrocarbons and risk for premature ovarian failure and reproductive hormones imbalance

Polycyclic aromatic hydrocarbons (PAHs) are a typical class of persistent organic pollutants that is ubiquitous worldwide. Previous animal studies suggested that PAHs had adverse effects on female reproduction. However, the human data regarding relationship of PAHs exposure with women reproductive health, such as ovarian dysfunction, are scarce. In this case-control study, the associations of serum levels of PAHs with the risk of premature ovarian failure (POF) and reproductive hormones in Chinese women were investigated, with recruiting 157 POF patients and 217 healthy women. The serum levels of 12 types of PAHs, as well as reproductive hormones, including follicle-stimulating hormone, luteinizing hormone and anti-mullerian hormone, were determined. In the logistic regression models, most individual PAH congeners showed significantly positive correlations with the risk of POF (p < 0.05), except for fluorine and pyrene. Benzo(a)pyrene (BaP), as the most carcinogenic PAH congener, was observed to be significantly positively associated with the risk of POF. After adjustment for age, body mass index, educational levels and household income, per one-unit increase in the log-transformed BaP concentration was significantly correlated with 2.191-fold increased risk of POF (OR = 2.191, 95%CI: 1.634-2.938, p < 0.05). To the best of our knowledge, this is the first study to report an association between internal exposure levels of PAHs and the increased risk of POF in women.

Exposure to organochlorine pesticides and the risk of type 2 diabetes in the population of East China

Organochlorine pesticides (OCPs) have been reported to be associated with an elevated risk of type 2 diabetes, although no study has focused on such associations in Chinese populations. In this case-control study, we aimed to explore the associations between OCPs and type 2 diabetes and their potential mechanisms in a population from East China. Participants diagnosed with type 2 diabetes and nondiabetic participants from Shandong Province, East China, were enrolled in this case-control study. Six OCPs (β-HCH, trans-chlordane, trans-nonachlor, p,p'-DDE, p,p'-DDT and mirex/kepone) were detected in more than 75% of serum samples. Logistic regression analysis and multiple linear regression analysis were used to assess the associations between OCP exposure and the outcomes. After adjusting for potential confounding factors such as age, sex and body mass index, all six OCPs showed positive associations with type 2 diabetes in a linear dose-response manner. Serum concentrations of β-HCH and p,p'-DDE were associated with higher levels of fasting plasma glucose in participants without diabetes, although no OCPs showed significant associations with hemoglobin A1c. In addition, certain OCPs showed significantly positive associations with triglycerides, total cholesterol, and low-density lipoprotein cholesterol and negative relationships with high-density lipoprotein cholesterol in nondiabetics, indicating that OCP exposure may disrupt lipid metabolism. Findings in the current study indicated that OCPs may be a diabetogenic factor in the population of this study. To our knowledge, this is the first study to investigate the associations between OCP exposure and type 2 diabetes in a Chinese population.

Health risk assessments based on polycyclic aromatic hydrocarbons in freshwater fish cultured using food waste-based diets

Two farmed freshwater fish species Nile tilapia (Oreochromis niloticus) and jade perch (Scortum barcoo) were cultured with food waste-based diets and compared with commercial formulated control diet for a period of six months. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) in the diets and cultured fish meat were tested by gas chromatography-mass spectrometry. No significant differences of ∑PAHs were observed between Nile tilapia and jade perch fed with food waste-based diets and control diet (p > 0.05). However, there were significantly higher concentration of ∑PAHs in market fish compared with the same species of fish fed by food waste-based diets (p < 0.05). Thus, the food waste-based diets have a potential to lower the PAH concentrations in farmed fish when compared with market fish. Based on the PAH concentrations, a human health risk assessment was made. The results indicated there were no non-cancer and very low cancer risks of consuming fish cultured with food waste-based diets at the 95th centile (Nile tilapia: hazard index (HI _adult) = 0.343 × 10^-3, HI _children = 0.614 × 10^-3 and cancer risk value = 0.943 × 10^-6; jade perch: HI _adult = 0.456 × 10^-3, HI _children = 0.814 × 10^-3 and cancer risk value = 0.291 × 10^-6). In general, the fish fed with food waste-based diets were unlikely to cause adverse health effects, based on the concentrations of PAHs. There is great potential for using food waste-based diets as an alternative to commercial feeds for cultivating freshwater fish.

Polybrominated diphenyl ethers (PBDEs) in plasma from E-waste recyclers, outdoor and indoor workers in the Puget Sound, WA region

Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants in consumer products including electronic devices. Important routes of human exposure are contaminated food and contact with dust. In this study, we measured twelve PBDEs in household/workplace dust and blood plasma samples provided by 113 volunteers living in the Puget Sound region, WA and working at electronic waste (E-waste) recycling sites (n = 29) or non-specific indoor (n = 57) or outdoor occupations (n = 27). The volunteers in the outdoor group were also selected because of a history of high seafood consumption habits. Results indicated the sum PBDE levels varied between <2.5 and up to 310 ng g^-1 lipid. E-waste recyclers were predominantly men, generally consumed low amounts of seafood, and had PBDE blood levels (geometric mean, GM = 26.56 ng g^-1 lipid) that were similar to indoor workers (GM = 27.17 ng g^-1 lipid). The sum PBDE levels were highest in the outdoor group (GM = 50.63 ng g^-1 lipid). Dust samples from E-waste sites were highly enriched with BDE-209 and BDE-153 relative to non-E-waste businesses and homes. The concentrations of these BDE congeners in dust at E-waste sites were ∼32-39 times higher than in dust from other sites. However, the detection rate of BDE-209 in plasma was low across all groups (13%) and no statistical comparisons were made. Our results suggest that E-waste recyclers in this study population did not have elevated PBDE levels in comparison to volunteers working in other types of occupations.

Spatial distribution and source identification of hydrophobic organic compounds (HOCs) on sedimentary microplastic in Hong Kong

The spatial distribution, composition and source of hydrophobic organic compounds (HOCs) including polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs) of the sedimentary microplastics (0.25-5 mm) in Hong Kong were investigated. The concentration of ΣPAHs ranged between 70.8 and 1509 ng g^-1 with inter-site differences although the regional difference was insignificant, indicating localised pyrolytic and petrogenic input of PAHs. The concentration of ΣPCBs (13-1083 ng g^-1) varied with both study sites and regions with higher concentrations obtained in the western waters, possibly due to the input from Pearl River. Significantly higher concentrations of OCPs on eastern shores highlighted fishing and aquaculture activities in South China Sea a potential major source of OCPs. DDT and its metabolites (DDX, ranged from 1.96 to 626 ng g^-1) were the dominant forms of OCPs (45%-80%). Since most of the DDX existed as DDT, this suggested that there was a fresh input of DDT into the microplastics. As microplastics and HOCs cannot be removed effectively from the environment, reduction of potential ecotoxicological risks should rely on minimizing the use of plastics and HOCs.

Cyclodextrin-Promoted Fluorescence Detection of Aromatic Toxicants and Toxicant Metabolites in Commercial Milk Products

The detection of polycyclic aromatic hydrocarbons (PAHs) and their metabolites in food and in agricultural sources is an important research objective due to the PAHs' known persistence, carcinogenicity, and toxicity. PAHs have been found in the milk of lactating cows, and in the leaves and stems of plants grown in PAH-contaminated areas, thereby making their way into both cow milk and plant milk alternatives. Reported herein is the rapid, sensitive, and selective detection of 10 PAHs and PAH metabolites in a variety of cow milks and plant milk alternatives using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, combined with subsequent array-based statistical analyses of the fluorescence emission signals. This system operates with high sensitivity (low micromolar detection limits), selectivity (100% differentiation even between structurally similar analytes), and general applicability (for both unmodified lipophilic PAHs and highly polar oxidized PAH metabolites, as well as for different cow and plant milk samples). These promising results show significant potential to be translated into solid-state devices for the rapid, sensitive, and selective detection of PAHs and their metabolites in complex, commercial food products.

Transplacental transfer characteristics of organochlorine pesticides in paired maternal and cord sera, and placentas and possible influencing factors

Organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane (DDT) and its metabolites [dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane], hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB), are widely detected in humans despite the considerable decline in environmental concentrations. To understand the placental transfer of OCPs and the possible maternal influence on them, we measured the concentrations of DDTs, HCHs, and HCB in 102 paired samples of maternal and cord sera, and placentas collected in Shanghai, China. The median concentrations of DDTs and HCHs were the highest in maternal sera (601, 188 ng g^-1 lipid), followed by umbilical cord sera (389, 131 ng g^-1 lipid), and placentas (65, 37 ng g^-1 lipid). 4,4'-DDE, β-HCH, and HCB were the predominant contaminants in the three matrices. The ubiquitous existence of OCPs, and the significant concentration relationships of DDTs, HCHs, and OCPs in the three matrices suggested placental transfer from mother to fetus. The lipid-based concentration ratios of 4,4'-DDE, β-HCH, and HCB in umbilical cord serum to those in maternal serum (F/M), and ratios of placenta to maternal serum (P/M) ranged from 0.66 to 1.01, and 0.12 to 0.25, respectively. Maternal variables affected the levels of fetal contamination. For primiparous women, significant correlations between maternal age and maternal HCHs, and between pre-pregnancy body mass index (BMI) and maternal HCHs were found. The negative effect of parity, and the positive effect of food consumption on maternal OCP concentrations were also observed, although there were no significant differences. The possible influence of parity on F/M and P/M of 4,4'-DDE suggested borderline significant differences between primiparous and multiparous women. Also, slight group differences were observed between elder and younger women, and between overweight and normal/underweight women. Parity seems to have a potential influence on transfer ratios of some OCP pollutants.

Efficient Fluorescence Detection of Aromatic Toxicants and Toxicant Metabolites in Human Breast Milk

Once chemical contaminants are released into the environment, there are a number of concerns that arise regarding the environmental persistence of the contaminants, their known and suspected toxicities, and their potential disruption to the ecosystem. One class of contaminants that is of continuing concern is polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants that are significant components of oil spills. PAHs have been found in the breast milk of nursing mothers living in oil spill affected regions, and can harm the nursing children. We report herein the sensitive and selective detection of 10 PAHs and PAH metabolites in human breast milk using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, and array-based statistical analyses of the resulting fluorescence responses. This detection system was able to separate and identify the PAHs with 100% success in human breast milk and at concentrations as low as 0.17 μM. These results have significant implications in public health and in the monitoring and mitigation of environmental disasters.

Organochlorine pesticide concentrations in pooled serum of people in different age groups from five Chinese cities

Organochlorine pesticides (OCPs) were determined in human serum samples pooled by donor age (≥60, 50-59, 40-49, 30-39, and 20-29y). The pooled samples were supplied by hospitals in five Chinese cities, Yitong (Jilin Province), Weifang (Shandong Province), Ganzi (Sichuan Province), Huaihua (Hunan Province), and Lingshui (Hainan Province). p,p'-Dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), β-hexachlorocyclohexane (HCH), and endosulfan I were the dominant OCPs in the serum samples. The total OCP concentrations and individual concentrations of p,p'-DDE, HCB, and β-HCH were relatively high compared with concentrations that have been found in other parts of the world. The total OCP, p,p'-DDE, and β-HCH concentrations decreased as age decreased but the HCB and endosulfan I concentrations were slightly higher in the samples from younger donors than in samples from older donors. HCB must be currently used and have new sources to people to cause this. Chinese government policies and the characteristics of the OCPs have led to OCP concentrations in serum decreasing with decreasing age. Different OCP usage patterns in different Chinese cities have led to the inhabitants of different cities having different OCP distributions in their serum.

Risk profile and health vulnerability of female workers who pick cotton by organanochlorine pesticides from southern Punjab, Pakistan

The present study was conducted to highlight the existing level of organochlorine-pesticides (OCPs) from human milk (n = 45) and blood serum (n = 40) of female workers who pick cotton in Khanewal District, southern Punjab, Pakistan. Source apportionment, congener-specific analysis, and risk surveillance of OCPs are reported from human milk and blood samples. Levels of OCPs in milk and blood serum samples ranged from 15.7 ppb to 538.3 ppb and from 16.4 ppb to 747.1 ppb, respectively, and were lower than previously published reports from other regions of the globe. Congener-specific analysis revealed that DDTs were predominant, followed by hexachlorocyclohexane, chlordane, and hexachlorobenzene. Calculated results for source apportionment analysis suggested that contamination load was a new input of DDTs as well as the historic use of lindane in the study area. Levels of OCPs in milk and blood serum were significantly (p < 0.05) correlated with age, time period of picking cotton, and number of children. Health risk revealed that female workers had risk of cancer among 1 per million; however, noncarcinogenic risks were not considerable. Environ Toxicol Chem 2017;36:1193-1201. © 2016 SETAC.

Temporal and spatial distribution, sources, and potential health risks of ambient polycyclic aromatic hydrocarbons in the Yangtze River Delta (YRD) of eastern China

In this study, from July 2011 to June 2012, 31 sampling sites were identified in order to investigate the concentrations and sources of polycyclic aromatic hydrocarbons (PAHs), as well as to evaluate their potential health risks in the cities of Suzhou, Wuxi, and Nantong, which are located in the Yangtze River Delta (YRD). The samples were collected by means of passive air sampling (PAS), and the contents of 15 PAHs were detected by gas chromatography-mass spectrometry. The ∑₁₅PAHs concentrations were found to range from 6.48 to 154 ng m^-3, with an average value of 56.8 ± 14.8 ng m^-3. The pollution levels in Suzhou and Nantong were higher than those in Wuxi. Furthermore, the concentrations of the PAHs in the urban sites were determined to be higher than those in the suburban sites for ambient air. The seasonal average contents were found to be at a maximum in autumn, with concentrations reaching 74.1 ng m^-3. Vehicle emissions and coal/biomass combustion were the dominant sources of the PAHs in the ambient air, with the contributions of 48% and 46%, respectively. The BaP TEQ (0.88 ng m^-3) was found to have surpassed the Chinese and Japanese dioxin emission limit, and in doing so, may have caused a certain degree of risk to human health.

Transplacental transfer of polycyclic aromatic hydrocarbons in paired samples of maternal serum, umbilical cord serum, and placenta in Shanghai, China

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is a high-priority public health concern. However, maternal to fetal transplacental transfer of PAHs has not been systematically studied. To investigate the transplacental transfer of PAHs from mother to fetus and determine the influence of lipophilicity (octanol-water partition coefficient, K_OW) on transfer process, in the present study, we measured the concentrations of 15 PAHs in 95 paired maternal and umbilical cord serum, and placenta samples (in total 285 samples) collected in Shanghai, China. The average concentration of total PAHs was the highest in maternal serums (1290 ng g^-1 lipid), followed by umbilical cord serums (1150 ng g^-1 lipid). The value was the lowest in placenta samples (673 ng g^-1 lipid). Low molecular weight PAHs were the predominant compounds in the three matrices. Increases in fish and meat consumption did not lead to increases in maternal PAH levels, and no obvious gender differences in umbilical cord serums were observed. The widespread presence of PAHs in umbilical cord serums indicated the occurrence of transplacental transfer. The ratios of PAH concentrations in umbilical cord serum to those in maternal serum (F/M) and the concentrations in placenta to those in maternal serum (P/M) of paired samples were analyzed to characterize the transfer process of individual PAHs. Most F/M ratios on lipid basis were close to one (range: 0.79 to 1.36), which suggested that passive diffusion may control the transplacental transfer of PAHs from maternal serum to the fetal circulation. The P/M and F/M values calculated on lipid basis showed that PAHs with lower K_OW were more likely to transfer from mother to fetus via the placenta.

Comparison of in vitro digestion model with in vivo relative bioavailability of BDE-209 in indoor dust and combination of in vitro digestion/Caco-2 cell model to estimate the daily intake of BDE-209 via indoor dust

There is limited information on the BDE-209 relative bioavailability (RBA) of indoor dust and the absorption of BDE-209 after in vitro digestion was seldom studied. In the present study, BDE-209 RBA in 6 household dust samples measured using an in vivo mouse model was compared to BDE-209 bioaccessibility determined using physiologically based extraction test (PBET) and solubility bioaccessibility research consortium method (SBRC) assays. BDE-209 RBA obtained ranged from 45.9 ± 16.1 to 96.0 ± 17.4% and exhibited a significant relationship with PBET gastric phase (r² = 0.578, p = 0.080), small intestinal phase (r² = 0.728, p = 0.031) and total BDE-209 bioaccessibility (r² = 0.728, p = 0.031), which indicated PBET assay can serve as a surrogate to predict BDE-209 RBA to refine human health exposure. In addition, the absorption of BDE-209 by Caco-2 cell line was assessed. With the consideration of the corresponding bioaccessibility and absorption of BDE-209 by Caco-2 cell line, the human daily intake of BDE-209 via dust ingestion for adults and children was much lower than that estimated by total concentration.

Organohalogenated contaminants in type 2 diabetic serum from Jeddah, Saudi Arabia

Most of the organohalogenated contaminants (OHCs) have high environmental stability and are lipophilic in nature, thus bioaccumulate through the various routes e.g., inhalation, dermal contact and food intake. Human exposure to these OHCs can induce adverse health effects. Studies on the occurrence of OHCs in human samples from Saudi Arabia are scarce. Therefore, this study aimed at providing preliminary insight on the occurrence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated biphenyl ethers (PBDEs) in diabetic and non-diabetic donors from KSA. Serum samples were collected from type 2 diabetic patients (n = 40) and control donors (n = 20) to study the impact of OHCs on their health. For the first time we studied the difference of ƩOHCs in type 2 diabetic and control participants. The order of obtained results was ƩOCPs (35-650 ng/g lw)> ƩPCBs (15-90 ng/g lw)> ƩPBDEs (1.5-68 ng/g lw). The major contributors were p,p'-DDE (median 44 ng/g lw), PCB 153 (2.3 ng/g lw), PCB 138 (2.1 ng/g lw), BDE 153 (1.2 ng/g lw) and BDE 47 (0.85 ng/g lw). Exposure to different OHCs between male and female donors was not significantly different (p > 0.05). However, ƩPCBs and ƩOHCs were significantly higher (p < 0.05) in diabetic donors than those of control group. We computed significantly positive correlations (p < 0.05) among different OHCs and between OHCs and age factor. The current study highlights the presence of different OHCs in humans from Jeddah, KSA. This is a preliminary study based on small sample size but our results suggested that detailed studies are required to understand the sources of these pollutants and their impact on human health.

Investigation into atmospheric PM2.5-borne PAHs in Eastern cities of China: concentration, source diagnosis and health risk assessment

This study investigated PM2.5-PAHs associations collected in Beijing, Jinan, and Shanghai in Eastern China. The results indicated that PM2.5 concentrations in Beijing, Jinan, and Shanghai were 125.7 μg m(-3) (18.6-355.5 μg m(-3)), 115.9 μg m(-3) (44.2-345.4 μg m(-3)), and 85.1 μg m(-3) (24.3-232.8 μg m(-3)), respectively. The PAH concentrations in terms of PM2.5 in Beijing, Jinan, and Shanghai ranged from 23.2 to 819.8 ng m(-3), 25.7 to 727.1 ng m(-3), and 8.5 to 133.9 ng m(-3), respectively. PAH concentrations were found to be positively correlated with PM2.5 concentration in Beijing and Shanghai. The compositions of PAHs in PM2.5 in Beijing and Jinan were almost the same: 11% low ring, 80-82% middle ring, and 7-9% high ring. However, Shanghai had a different composition. Source apportionment indicated that the incomplete combustion of coal and diesel and gasoline emissions were the main sources of PAHs in PM2.5 in all three cities, whereas Shanghai had a greater contribution from liquid fossil fuels. The values for the health risk assessment estimated by the benzo[a]pyrene equivalent concentration in Beijing and Jinan were 2.39 × 10(-6) and 2.57 × 10(-6), respectively, thus both exceeding the 1 × 10(-6) limit (USEPA) considered likely to pose an inhalation cancer risk to people. Shanghai, however, had a risk estimate of 5.05 × 10(-7), which is still in a safe range. This study is the first to simultaneously monitor the PAHs in PM2.5 in three cities in Eastern China and may point to a long-range transportation of PM2.5-PAHs from Beijing to Jinan and partially to Shanghai.

Interactions of 1-hydroxypyrene with bovine serum albumin: insights from multi-spectroscopy, docking and molecular dynamics simulation methods

Combining multi-spectroscopy, docking with MD simulations, the interactions of 1-hydroxypyrene with BSA and the adverse effects on BSA were investigated.

The effect of environmental chemicals on the tumor microenvironment

Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis.

The associations between metals/metalloids concentrations in blood plasma of Hong Kong residents and their seafood diet, smoking habit, body mass index and age

The concentrations of metals/metalloids in blood plasma collected from 111 healthy residents (51 female, 60 male) in Hong Kong (obtained from the Hong Kong Red Cross Blood Transfusion Service, from March to April 2008) were quantified by means of a double-focusing sector field inductively coupled plasma optical emission spectrometer (ICP-OES). Results showed that concentrations of these toxic metals such as Hg, Cd, and Pb in Hong Kong residents were not serious when compared with other countries. Males accumulated significantly higher (p < 0.05 or 0.01) Fe (female 0.92 mg/L; male 1.28), Sn (0.44 μg/L; 0.60), Cr (0.77; 0.90), Hg (1.01; 1.73), and Pb (23.4; 31.6) than females. Smokers accumulated significantly higher (p < 0.05) Cd (smoker 0.27 μg/L; nonsmoker 0.17) and Pb (32.8; 17.6) than nonsmokers. Positive correlations were found between concentrations of As, Cd, Pb, and Hg, with respect to seafood diet habit, body mass index (BMI), and age. More intensive studies involving more samples are needed before a more definite conclusion can be drawn, especially on the causal relationships between concentrations of metals/metalloids with dietary preference and lifestyle of the general public.

Methyl siloxanes in environmental matrices and human plasma/fat from both general industries and residential areas in China

We investigated human exposure to methyl siloxanes in three general industries (building, automobile, and textile industries) and residential areas in China. Usage volumes of methyl siloxanes per capita in these industries were 2-5 orders of magnitudes higher than those in residential areas. Methyl siloxane concentrations in indoor air and dust samples from industrial facilities were 1-3 orders of magnitudes higher than those in residential houses. Both cyclic (D4-D6) and linear (L5-L16) siloxanes were detected in plasma of industrial workers (1.00-252 ng/mL, detection frequencies=3.7-71%, n=528), while only cyclic compounds (D4-D6) were detected in plasma of general population (n=519) with much lower concentrations (1.10-7.50 ng/mL) and detection frequencies (1.7-3.7%). During the occupational exposure, anti-dust mask can reduce 30% of intake of cyclic siloxanes and 74% of intake of linear siloxanes, respectively. In addition, PM-10 could elevate intake of linear siloxanes. Calculated fat-plasma partition ratios of methyl siloxanes (D4-D6, L6-L11) in the present study were 5.3-241 mL/g. Linear rather than cyclic siloxanes had an apparent accumulation in abdominal fat. Population's half-lives of L8-L10 in abdominal fat of general population were approximately 1.49-1.80 years.

Polycyclic aromatic hydrocarbon residues in serum samples of autopsied individuals from Tennessee

This study reports the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in human blood sera samples (n = 650) obtained at autopsy from individuals who died of drug abuse, alcohol toxicity, homicide, suicide and other unknown causes. The analyzed samples from decedents revealed the presence of PAHs of which B(a)P was the most predominant one, followed by benzo(b)fluoranthene and benzo(k)fluoranthene. The other PAHs detected sporadically and measured were benzo(g,h,i)perylene, acenaphthene, anthracene, phenanthrene, and fluoranthene The mean concentrations of PAHs were greater in the twenties to fifties age groups compared to others. The PAH residue levels detected were high in African Americans compared to Caucasians, Asians, and Hispanics. It appears that environmental exposure, dietary intake and in some cases occupational exposure may have contributed to the PAH body burden. While the PAH residue concentrations measured fall within the range of those reported for healthy adults elsewhere, in isolated cases, the concentrations detected were high, calling the need for a reduction in PAH emissions and human biomonitoring studies for purposes of risk assessment.

Polychlorinated biphenyls and selected organochlorine pesticides in serum of Slovak population from industrial and non-industrial areas

The concentrations of indicator polychlorinated biphenyls (PCBs No. 28, 52, 101, 138, 153 and 180) and organochlorine pesticides (HCB, p,p'-DDE and p,p'-DDT) in 121 blood serum specimens collected from non-occupationally exposed adults living in contaminated and comparison areas were determined using high-resolution gas chromatography/electron capture detection (HRGC/ECD). The sum of the serum concentrations of the three most abundant PCB congeners (No. 138, 153 and 180) found in participants (N = 81) living in industrial areas near incinerators, metallurgical and chemical plants (Krompachy, Kosice, Nemecka and Sala) was significantly higher (p < 0.001) than in participants living in villages and towns without known sources causing persistent organic pollutant (POP) contamination (N = 40). Similarly, significant differences were observed for p,p'-DDE (p < 0.0001) and p,p'-DDT (p < 0.002). However, a Mann-Whitney U test between groups showed that the difference for HCB was not statistically significant (p = 0.089). Age was positively correlated with the sum of PCBs (No. 138, 153 and 180), HCB and the sum of p,p'-DDE and p,p'-DDT (p < 0.01 for all).

Serum concentrations of organochlorine pesticides p,p'-DDE in adult Thai residents with background levels of exposure

In Thailand, DDT was banned for agriculture use in 1983 and for malaria vector control in 1999. However, contamination by DDT and its primary metabolite, p,p'-DDE remains serious environmental and human health concerns. The main focus of this study were i) to investigate serum concentrations of p,p'-DDE and p,p'-DDT as exposure biomarkers for potential adverse health effect in adult Thai residents and ii) to compare the associations of BMI, thyroid hormones, cholesterol, triglycerides and fasting blood sugar levels in human serum with the concentrations of these pesticides. In a total of 1,137 participants were measured blood serum for analyses of p,p'-DDE and p,p'-DDT. The geometric mean concentration (95% confidence interval) for serum total p,p'-DDE concentration was 1,539 (1,242-1,837) ng/g lipid and 1,547 (1,293-1,806) ng/g lipid in adult males and females, respectively. Furthermore, the total amount of serum p,p'-DDE concentration significantly correlated with plasma glucose levels. Neither p,p'-DDE nor p,p'-DDT was significantly associated with serum thyroid hormones levels. Additionally, the high p,p'-DDE/DDT ratio indicates that the exposure is due past rather than recent use of DDT.

Concentrations and congener profiles of polybrominated diphenyl ethers (PBDEs) in blood plasma from Hong Kong: implications for sources and exposure route

There was limited information about bioaccumulation of polybrominated diphenyl ethers (PBDEs) in humans of the general population of Hong Kong. Therefore, the present study was conducted to determine concentrations and congener profiles of PBDEs in blood plasma from Hong Kong, evaluate their sources and correlations with other organobrominated compounds, and investigate exposure routes from fish and dust. Concentrations of ∑PBDE22 ranged from 0.56 to 92 ng g(-1), lipid weight (lw), with a median of 5.4 ng g(-1). BDE-47 was the dominant congener, accounting for 26% of ∑PBDE22. Concentrations of PBDE congeners in market fish were significantly (r(2)=0.89, p<0.001) correlated with plasma. Positive but no significant correlations were observed, between concentrations of PBDE congeners in indoor dust from workplaces (r(2)=0.46, p=0.081) and homes (r(2)=0.49, p=0.10), with concentrations of PBDE in human blood plasma. The results indicated that dietary exposure, particularly consumption of fish, is a major pathway through which people in Hong Kong are exposed to PBDEs. Furthermore, our data revealed a spatial distribution and terrestrial source of BDE-28 for local people. Results of the present study, which was the first systematic study to investigate concentrations of PBDEs in blood of Hong Kong people, provides useful information to which future measurements can be compared.

Investigation of polycyclic aromatic hydrocarbon level in blood and semen quality for residents in Pearl River Delta Region in China

This study is the first one investigating the correlation between the concentration of polycyclic aromatic hydrocarbon (PAHs) in blood and semen qualities for residents in the Pearl River Delta (PRD) region in China. Blood samples from 53 infertile volunteers were studied for measures of semen quality and 16 PAHs. Information on the study subjects' living habits (such as smoking, drinking and preference of consumption for food) and general information (age, body-mass-index (BMI) and educational background) were also collected. Statistical results showed that age and BMI were significantly and negatively related to semen motilities. The total concentrations of PAHs (∑16 PAHs) in the blood were 12,010, 7493, 9105 and 8647ng/g for factory workers, office workers, technicians and salespersons, respectively. In addition, ∑16 PAHs in the blood of smokers, drinkers and heavy-taste food consumers were 11,950, 11,266 and 12,141ng/g, which were higher than those observed in nonsmokers (10,457ng/g), nondrinkers (10,920ng/g) and light-taste food consumers (9202ng/g), individually. Furthermore, the Pearson correlation analysis results showed significant positive correlations between BMI and ∑16 PAHs in the blood. Statistically significant correlations were observed between semen motilities and ∑16 PAHs in the blood as well. Logistic regression results showed that for each 1ng/g increase in ∑16 PAHs in blood samples, the log odds of experiencing a pregnancy decrease by 0.039 on average. However, more evidences are needed to clarify the impact of PAHs in the blood to male infertility.

A review of environmental and human exposure to persistent organic pollutants in the Pearl River Delta, South China

Rapid economic growth in South China (including Guangdong Province, Hong Kong, and Macau), particularly within the Pearl River Delta region, has resulted in severe pollution of the natural eco-environment in the last three decades. Large amounts of monitoring data on organic pollution in the Pearl River Delta have been accumulated, which allows us to conduct a fairly comprehensive assessment of the state of the Pearl River Delta and elucidate spatial and temporal patterns of pollution on a regional scale. Of various causes for environmental deterioration, negative impact from persistent organic pollutants (POPs) is a global concern. This review examines the current levels and distribution patterns of several POPs, namely DDT (and its metabolites DDD and DDE), hexachlorocyclohexanes, and polybrominated diphenyl ethers, in various environmental compartments of South China. The general information on environmental occurrence, regional behaviors, ecological effects, and human exposure of these POPs in this region are reviewed.