Individual Polychlorinated Biphenyls Congeners Research Articles

ПОЛИХЛОРИРОВАННЫЕ БИФЕНИЛЫ В ВОДНОЙ ЭКОСИСТЕМЕ ЗАПОВЕДНОГО ОЗЕРА МАРКАКОЛЬ И ВПАДАЮЩИХ В НЕГО РЕК

The article presents the results of the study of polychlorinated biphenyls (PCBs) pollution of water and bottom sediments of Markakol Lake and rivers of its basin. Brief information about the importance of studying the accumulation and distribution of these dangerous xenobiotics in water bodies and watercourses of the republic in order to realize the tasks adopted by the Republic of Kazakhstan in accordance with the requirements of the global Stockholm Convention on Persistent Organic Pollutants (POPs) is presented. The conducted research f irst of all showed pollution of water resources and bottom sediments of the lake and rivers located in the protected area. Uneven distribution of toxicant concentration over the lake water area both in water and bottom sediments was revealed. The highest toxicant concentrations were registered in the water of the Kalzhyr River outflowing from the lake. In lake and river waters, 30 individual PCB congeners were detected, among which highly toxic dioxin-like and «marker» congeners are present. Other congeners with rather high toxicity were also found in water resources. Based on the scientific results of scientists from far and near abroad in the field of problems of distribution of these toxicants on the planet, the hypothesis about atmospheric transfer of these toxic compounds to this protected zone from highly PCB polluted territories was made.

Sources of polychlorinated biphenyls (PCBs) in sediments of the East China marginal seas: Role of unintentionally-produced PCBs

The production and use of intentionally-produced polychlorinated biphenyls (PCBs) in China have a short history compared with countries of North America and Europe, where technical PCB mixtures were manufactured in large amounts for decades before being banned. Unintentionally-produced PCB emissions increased dramatically in China, leading to unique profiles of PCB burdens. This study first time evaluated 208 individual PCB congeners at 94 sites from surface sediments of the East China Marginal Seas (ECMSs) and explored their sources. Non-technical PCBs transported from atmospheric transport and river discharge played a dominant role in most areas of the ECMSs, while historical residuals of technical PCBs occupied the fine-grained sediments in muddy areas of the central Yellow Sea (YS), regarding to the low sedimentation rate in the central YS. Furthermore, emissions from Taizhou located on the coast of the East China Sea (ECS), which is an important electronic waste dismantling site in East China, contributed additional technical PCBs to the inner shelf of the ECS. Our results indicate that non-technical PCBs have become the dominant PCB species in the ECMSs, and emphasize the synergistic effects of large riverine input, long-range atmospheric transport, and muddy shelf deposition on PCB source and sink of in marginal seas.

Assessing Polychlorinated Biphenyls (PCBs) Contamination in Indoor Dust among University Students in Ilorin, Nigeria

Background: This study aimed to assess the contamination of Polychlorinated Biphenyls (PCBs) in indoor dust among university students in Ilorin, Nigeria. Methods: One hundred (100) indoor dust samples were collected from different locations within university hostels. Two Universities in Ilorin were sampled for the study; the Univerisity of Ilorin and Al-Hikmah University. Gas chromatography-mass spectroscopy (GC-MS) was employed to analyze and identify fourteen PCB congeners. Results: The results revealed that university students were exposed to low levels of PCB contamination in indoor dust. The concentrations of individual PCB congeners ranged from 4.993ng/g to 37.701ng/g. Notably, PCB-52 and PCB-118 were the predominant congeners, with mean concentrations of 37.701ng/g and 30.928ng/g. Conversely, PCB-44 exhibited the lowest occurrence, with a mean concentration of 4.993ng/g. The study found positive correlations among specific PCB congeners, suggesting familiar sources and environmental behaviors. However, no significant correlations were found between residential characteristics and measured PCB levels. Conclusion: The results emphasize the need for further research to minimize PCB contamination in indoor environments and protect human health. It is recommended that PCB levels be monitored in indoor environments and enforce strong regulations to control PCB production, use, and disposal.

Hydrodynamic Impacts on the Fate of Polychlorinated Biphenyl 153 in the Marine Environment

Due to their long half-life, polychlorinated biphenyls (PCBs) tend to contaminate not only coastal areas, but they travel over long distances, eventually reaching remote areas such the Arctic. The physical and biogeochemical features of every coastal area govern the main distribution patterns of freshly introduced PCBs into the marine system. Some of these processes are determined by chemical properties of the individual PCB congener. Thus, atmospheric influx along with ad/absorption on non-living organic material, photolytical and biological degradation processes vary from one PCB congener to another. For a detailed fate analysis of individual congeners, we developed a new chemical model, based on the GOTM-ECOSMO-FABM model framework. Here, we exemplarily present results for PCB153 based on 1D simulations of four regions in the North-Baltic Sea. The study area is characterized by different hydrodynamic and biogeochemical conditions. We investigate the impact of resuspension, mixing and the biological pump, sea ice and tides on the final phasal distribution of PCB153. Different combinations of these factors lead to the development of different areas of PCB153 accumulation, with the formation of hotspot areas, and influence the total uptake and concentration of PCB153 in the water column. As a result, two major dynamics determine the fate of PCB153 in the coastal ocean: (i) Primary production leads to PCB153 being adsorbed by organic material. Partitioning to organic material and sedimentation of organic particles removes dissolved PCB153 from the surface ocean and increases atmospheric influx. (ii) Tidal-induced resuspension and mixing control the benthic–pelagic exchange of PCB153 and its distribution in the water column. Depending on the resuspension regime and stratification, sediments can become a permanent (Gotland Deep, the Baltic Sea) or seasonal sink for PCB153. In regions with seasonal stratification and high near bottom turbulence (Northern North Sea), resuspension events can lead to pronounced peaks in PCB153 concentrations and can therefore have a major impact on bioaccumulation. Under the conditions of permanent mixing and high bottom turbulence (Southern North Sea, Bothnian Bay), pollutants are hardly accumulating in sediments.

Polychlorinated Biphenyls in the Snow Cover of South-Eastern Kazakhstan

The presence of large sources of environmental pollution due to persistent organic pollutants (POPs), in particular, polychlorinated biphenyls (PCBs), in Kazakhstan necessitates the assessment of pollution as a result of these toxicants. For this purpose, we chose snow cover as an indicator for assessing pollution status in the study area. An assessment of the PCB accumulation level included in the list of POPs was carried out for a snow cover (SC) study in south-east Kazakhstan. The content of PCBs with a wide congener composition was determined using the chromatographic analysis method. During the winter periods of 2014, 2015, 2018–2020 and 2021, the SC pollution of the study area from up to 25 individual PCB congeners was identified. These congeners included highly toxic dioxin-like congener PCBs 105; 108; 114; 118 and “marker” PCBs 52; 101; 138; 153. These congeners were mainly found in snow samples with a wide range of PCB congener compositions. The main PCB pollution sources were indicated. The analysis of the obtained results and structure of the congener composition of PCBs show that the SC contamination in this territory occurs under the influence of local and regional sources.

Occurrence and spatial distribution of individual polychlorinated biphenyl congeners in residential soils from East Chicago, southwest Lake Michigan

We report individual polychlorinated biphenyl congeners and the sum of all congeners (ΣPCB) in residential soils of East Chicago, Indiana. ΣPCB in soils ranged from 20 to 1700 ng/g dry weight (DW), with a geometric mean of 120 ng/g DW. These values are significantly higher than other locations, but similar or lower to locations nearby well-known PCB contamination sites. No PCB spatial distribution pattern was observed. PCB concentrations increase with total organic carbon in the soils and proximity to Indiana Harbor and Ship Canal (IHSC), where sediments are contaminated with PCBs. Most samples are similar in their PCB distribution and Aroclor 1254 yielded the highest similarity to all the samples. A fifth of the samples highly resemble other PCB profiles such as EPA background and Cedar Rapids Iowa soils, and volatilization from Lake Michigan, whereas volatilization from IHSC could not explain the PCBs found in soils. IHSC was expected to be the main source of PCBs in the nearby soils. It is possible that soils are impacted by variety of known and unknown sources, including volatilization from Lake Michigan, resulting in a regional PCB signal. Although PCB concentrations are higher than other locations, samples were below the current US EPA non-cancer residential soil level remediation goal for dioxin TEQ.

Geographic and Ethnic Variations in Serum Concentrations of Legacy Persistent Organic Pollutants among Men in the Nenets Autonomous Okrug, Arctic Russia.

The overwhelming majority of Arctic biomonitoring studies in humans include either pregnant or non-pregnant women of reproductive age while little attention is paid to toxic compounds concentrations in men. This study contributes with information of the present amounts of persistent organic pollutants (POPs) in men living in Arctic Russia. We studied the serum concentrations of 11 polychlorinated biphenyl (PCB) congeners and 17 organochlorine pesticides (OCPs) and some of their metabolites in samples collected from 92 adult men (mean age 43 years) from seven different settlements in Nenets Autonomous Okrug (NAO). The median concentrations of individual PCB congeners increased in the order PCB 183, PCB 180, PCB 118, PCB 138, PCB 153. The concentrations of o, p′-DDD, p, p′-DDD, aldrin, mirex and 1,2,3,5-TCB were in most cases below the quantification limit. The observed concentrations of PCBs and chlorinated pesticides were in the same range as those found in similar groups of women of these territories, but lower than of men in other Arctic countries. However, significant geographic differences between the settlements were observed with exceptionally high concentrations of PCBs in the Islands group. The highest serum ∑PCBs and β-HCH levels were observed in adult males aged 60–78 years. We found significant variations in serum concentrations of POPs across settlements and ethnic groups with exceptionally high concentrations of PCBs among the residents of the Arctic islands. At the same time, our findings suggest a considerable decrease in serum concentration of POPs over the last decade.

Association between Total and Individual PCB Congener Levels in Maternal Serum and Birth Weight of Newborns: Results from the Chiba Study of Mother and Child Health Using Weighted Quantile Sum Regression.

Maternal exposure to polychlorinated biphenyls (PCBs) during pregnancy is associated with a low birth weight; however, the congener-specific effects of PCB congeners are not well defined. In this study, we used maternal serum samples from the Chiba Study of Mother and Child Health (C-MACH) cohort, collected at 32 weeks of gestational age, to analyze the effects of PCB congener exposure on birth weight by examining the relationship between newborn birth weight and individual PCB congener levels in maternal serum (n = 291). The median total PCB level in the serum of mothers of male and female newborns at approximately 32 weeks of gestation was 39 and 37 ng g−1 lipid wt, respectively. The effect of the total PCB levels and the effects of PCB congener mixtures were analyzed using a linear regression model and a generalized weighted quantile sum regression model (gWQS). The birth weight of newborns was significantly associated with maternal exposure to PCB mixtures in the gWQS model. The results suggest that exposure to PCB mixtures results in low newborn birth weight. However, specific impacts of individual PCB congeners could not be related to newborn birth weight.

Occurrence and Spatial Distribution of Individual Polychlorinated Biphenyl Congeners in Residential Soils from East Chicago, Southwest Lake Michigan

Occurrence and Spatial Distribution of Individual Polychlorinated Biphenyl Congeners in Residential Soils from East Chicago, Southwest Lake Michigan

Particle/gas partitioning behavior of polychlorinated biphenyls (PCBs) in global atmosphere: Equilibrium or steady state?

Particle/gas (P/G) partitioning governs the atmospheric transport and fate of semi-volatile compounds (SVOCs). Here, we provide a comprehensive investigation of P/G partitioning of polychlorinated biphenyls (PCBs) by comparing the performance of seven models, (including five equilibrium models: Junge-Pankow model, Harner-Bidleman model, Dachs-Eisenreich model, pp-LFER model, mp-pp-LFER model, one empirical Li-Jia model, and one steady-state Li-Ma-Yang model). For this comparison, 5019 monitoring data points from urban, rural and remote sites for PCBs taken from published papers have been accessed, against which the predictions of these models have been evaluated. Among the 5019 monitoring data points, there are 2791 monitoring data for six selected PCB congeners (CB-28 + 31, −52, −101, −153, −180, −207) and 2228 for dozens of other PCB congeners. We find that in predicting the P/G partition quotient (KP) of the six selected PCB compounds, the Li-Ma-Yang model performs best across the entire logKOA (octanol-air partition coefficient) range (from 7.8 to 15.3), with 86 ± 10% of 2791 monitoring data points lying within a deviation of ±1 log unit of the root mean square error (RMSE) of 0.67 ± 0.18 in urban, rural and remote areas. This model is far superior to the other models in predicting KP, especially in the MP Domain (logKOA ≥ 12.50), with 96% of the data points falling within a deviation of ±1 log unit and a RMSE of 0.48, in comparison to the less than 7% for the five equilibrium models and 20% for the empirical Li-Jia model. These findings suggest that when the particle deposition is not negligible, the P/G partitioning of PCBs in ambient atmosphere is not in equilibrium, but in a steady or quasi-steady state. Similar to PBDEs, the properties of individual PCB congeners, such as KOA, are the primary factors affecting the P/G partitioning of PCBs.

A case-cohort study of perinatal exposure to potential endocrine disrupters and the risk of cryptorchidism in the Norwegian HUMIS study.

Exposure to endocrine-disrupting chemicals (EDCs) during the critical period of testicular descent may increase the risk of cryptorchidism and male fertility. To investigate 27 potential EDCs measured in breast milk as a proxy for perinatal exposure and the risk of cryptorchidism in a prospective cohort. The Norwegian Human Milk Study (2002-2009) enrolled 2606 mother-infant pairs, of which 1326 were mother-son pairs. In a case-cohort design, we studied 641 male infants who had 27 EDCs already quantified in milk samples: 5 organochlorine pesticides, 14 polychlorinated biphenyls (PCBs), 6 brominated flame retardants, and 2 poly- and perfluoroalkyl substances. We defined cases of congenital, recurrent, persistent and ever-reported cryptorchidism based on questionnaires mothers completed when children were 1, 6, 12 and 24months old. Variable selection via elastic net logistic regression identified the best cryptorchidism predictors while multivariable logistic regression models determined their effect estimates. The prevalence of reported congenital cryptorchidism was 6.1%, with half spontaneously descending within six months of birth, after which prevalence stabilized between 2.2 and 2.4%. The ever-reported prevalence of cryptorchidism at 1, 6, 12, or 24months was 12.2%. Elastic net models identified PCB-74 (OR=1.31, 95% CI: 1.001-1.703), PCB-114 (OR=1.36, 95% CI: 1.05-1.77), PCB-194 (OR=1.28, 95% CI: 1.03-1.53) and β-HCH (OR=1.26, 95% CI: 1.03-1.53 (per interquartile range increase in concentration of EDCs) as best predictors of congenital cryptorchidism. No EDCs were selected for either recurrent or persistent cryptorchidism, and only PCB-194 was selected by elastic net for ever-reported cryptorchidism (OR=1.23, 95% CI: 1.01-1.51), in contrast to unpenalized multivariable logistic regression, where most of the individual congeners of PCBs showed significant associations. In the largest multi-pollutant analysis to date considering potential confounding from co-exposure to other chemicals, perinatal exposure to PCB-74, PCB-114, PCB-194 and β-HCH were associated with increased odds of congenital cryptorchidism. Many PCBs may falsely be associated with cryptorchidism when assessed individually, due to confounding by highly correlated chemicals. Experimental studies are warranted to confirm our findings.

Assessment of binding potencies of polychlorinated biphenyls and polybrominated diphenyl ethers with Baikal seal and mouse constitutive androstane receptors: Comparisons across species and congeners

The present study evaluated the binding potencies (equilibrium dissociation constant: KD) of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) with the constitutive androstane receptor (CAR)_ligand binding domain (LBD) of the Baikal seal (bsCAR_LBD) and mouse (mCAR_LBD) using a surface plasmon resonance (SPR) biosensor. The binding affinities of individual congeners with mCAR_LBD tended to be higher than those with bsCAR_LBD but the differences were within the same order of magnitude. Notably, PBDE congeners showed higher binding affinities for both CAR_LBDs than PCB congeners. In silico docking simulations demonstrated that PBDEs had more non-covalent interactions with specific amino acid residues in both CAR_LBDs than PCBs, supporting the results of their binding affinities. Binding affinity comparisons among congeners revealed the structural requirements for higher binding; mono or di ortho-, tri meta-, and di para‑chlorine substitutions for PCBs, and di or tri ortho-, mono meta-, and di para‑bromine substitutions for PBDEs. The binding potencies of these congeners unlikely accounted for their previously reported CAR-mediated transactivation potencies, implying that their transactivation is regulated in a ligand-dependent, but a distinct manner from ligand binding. Risk assessment analysis showed that the KD values of individual PCB and PBDE congeners were 1-4 orders of magnitude higher than their respective hepatic concentrations in wild Baikal seal population.

Using tree swallows to assess reductions in PCB exposure as a result of dredging at Great Lakes Restoration Initiative (GLRI) sites in the Upper Midwest, USA.

Tree swallows (Tachycineta bicolor) were used to assess the effectiveness of reducing polychlorinated biphenyl (PCB) exposure to wildlife as a result of contaminated sediment removal at locations across the Great Lakes under two dredging scenarios, full or spot dredging. For comparative purposes, other locations where no dredging occurred were also assessed. Calculating accumulation rate, from the mass of a contaminant in tree swallow eggs and nestling carcasses, is a useful tool to assess the effectiveness of sediment removal. It has the advantage over more commonly used metrics such as cubic yards of sediment removed or kg of a contaminant removed, because it assesses a biotic endpoint that has more societal understanding. Egg and nestling concentrations of total PCBs and accumulation rate (μg of total PCBs accumulated per day) were compared pre- and post-dredge. At the most contaminated site, Waukegan Harbor, Illinois, the accumulation rate decreased by 95% because of dredging. At less contaminated locations in Wisconsin and Ohio, the accumulation rate was reduced by dredging as well, but not to such a large extent (~50%). Even at reference locations, there was a very small amount (0.01-0.06 μg/day) of PCBs accumulated each day because of the prevalence of this contaminant in the environment. The profile of individual PCB congeners also differed pre-and post-dredge and demonstrated significant changes as a result of dredging activities.

A Congener-specific and Mixture Analysis of Plasma Polychlorinated Biphenyl Levels and Incident Breast Cancer.

Polychlorinated biphenyls (PCBs), a diverse class of chemicals, are hypothesized mammary carcinogens. We examined plasma levels of 17 PCBs as individual congeners and as a mixture in association with breast cancer using a novel approach based on quantile g-computation. This study included 845 White and 562 Black women who participated in the population-based, case-control Carolina Breast Cancer Study Phase I. Cases (n = 748) were women with a first diagnosis of histologically confirmed, invasive breast cancer residing in 24 counties in central and eastern North Carolina; controls (n = 659) were women without breast cancer from the same counties. PCBs were measured in plasma samples obtained during the study interview. We estimated associations [covariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs)] between individual PCB congeners and breast cancer using multivariable logistic regression. We assessed PCB mixtures using quantile g-computation and examined effect measure modification by race. Comparing highest and lowest tertiles of PCBs resulted in ORs of 1.3 (95% CI = 0.95, 1.8) for congener 74, 1.4 (95% CI = 1.0, 1.9) for 99, 1.3 (95% CI = 0.91, 1.8) for 194, and 1.2 (95% CI = 0.90, 1.7) for 201. Among all women, we estimated a joint effect of the PCB mixture with an OR of 1.3 (95% CI = 0.98, 1.6) per tertile change. In race-stratified analyses, associations for tertiles of PCB mixtures were stronger among Black women (OR = 1.5; 95% CI = 1.0, 2.3) than among White women (OR = 1.1; 95% CI = 0.81, 1.6). Our results are consistent with the hypothesis that exposure to PCB mixtures increase the risk of breast cancer, but studies of populations with different exposure profiles are needed.

Serum polychlorinated biphenyl (PCB) levels and risk of testicular germ cell tumors: A population-based case-control study in Connecticut and Massachusetts.

The incidence rate of testicular germ cell tumors (TGCT) has continuously increased in Western countries over the last several decades. Some epidemiologic studies have reported that the endocrine disrupting polychlorinated biphenyls (PCBs) in serum may be associated with TGCT risk, but the evidence is inconsistent. Our goal was to investigate whether serum levels of PCBs are associated with the increase of TGCT risk. We conducted a population-based case-control study of 308 TGCT cases and 323 controls, all residents of Connecticut and Massachusetts. Serum levels of 56 PCBs congeners were measured using gas chromatography and unconditional logistic regression model was used to evaluate the risk of TGCT associated with total PCBs exposure, groups of PCBs categorized by Wolff's functional groups, and individual PCB congeners. The results showed that there was no association between total serum levels of PCBs and risk of TGCT overall (quartile 4 (Q4) vs. quartile 1 (Q1) odds ratio (OR) and 95% confidence interval (C.I.)=1.0 (0.6-1.9), ρ trend=0.9). However, strong positive association was observed between total serum levels of Wolff's Group 1 (potentially estrogenic) PCBs and risk of overall TGCT (Q4 vs. Q1 OR=2.5, 95% CI=1.3-4.7, ρ trend <0.05) as well as seminoma and non-seminoma subtypes. Wolff's Group 1 PCB congeners that showed an increased risk of TGCT included: 25, 44, 49, 52, 70, 101, 174, and 201/177. Considering the continuing increase of TGCT, these associations should be replicated in different populations with larger sample size.

Toxic Effects of Polychlorinated Biphenyl Congeners and Aroclors on Embryonic Growth and Development.

Polychlorinated biphenyls (PCBs) cause significant health and reproductive problems in many vertebrates. Exposure during embryogenesis likely leads to defects in organ development, compromising survival and growth through adulthood. The present study identifies the impact of PCBs on the embryonic development of key organs and resulting consequences on survival and growth. Zebrafish embryos were treated with individual PCB congeners (126 or 104) or one of 4 Aroclor mixtures (1016, 1242, 1254, or 1260) and analyzed for changes in gross embryonic morphology. Specific organs were assessed for defects during embryonic development, using a variety of transgenic zebrafish to improve organ visualization. Resulting larvae were grown to adulthood while survival and growth were assayed. Embryonic gross development on PCB treatment was abnormal, with defects presenting in a concentration-dependent manner in the liver, pancreas, heart, and blood vessel organization. Polychlorinated biphenyl 126 treatment resulted in the most consistently severe and fatal phenotypes, whereas treatments with PCB 104 and Aroclors resulted in a range of more subtle organ defects. Survival of fish was highly variable although the growth rates of surviving fish were relatively normal, suggesting that maturing PCB-treated fish that survive develop compensatory strategies needed to reach adulthood. Life span analyses of fish from embryogenesis through adulthood, as in the present study, are scarce but important for the field because they help identify foci for further studies. Environ Toxicol Chem 2021;40:187-201. © 2020 SETAC.

Advancing Kinetic Modeling for Polychlorinated Biphenyl (PCB) Mixtures Relevant to Human Exposures: A Case Study Applying the Keyword Analysis Tool to PCBs Congener-Specific Half-Lives

Toxicity resulting from human exposure to PCBs is highly dependent on the absorption, distribution, metabolism, and excretion (ADME) properties of individual PCB congeners. A database of half-life of elimination values for individual congeners was assembled to advance the development of a comprehensive kinetic model for PCB mixtures relevant to human exposures. A novel strategy was employed to identify relevant literature. First, a literature search was conducted using keywords related to PCBs; this generated a database of 58,915 studies. Next, the Keyword Analysis Tool (KAT) was applied to select studies related to PCB congener-specific half-lives across mammalian species. KAT is a software tool designed to increase efficiency in literature screening; it allows users to calculate metrics on the utility of each keyword. By applying keywords related to half-life, elimination, and clearance, KAT identified 5,956 potentially relevant studies from the PCB literature database. A text analytics approach was implemented to further select studies for data extraction. Specifically, sentences from the full text of each study that harbored a keyword were reviewed in conjunction with titles and abstracts to ascertain study relevance. This effort identified 312 studies, 98 of which contained half-life values for 95 PCB congeners across mammalian species. Data from 33 studies identified half-life values for 36 PCB congeners in humans across lifestages, biological matrices, and exposure routes. A retrospective analysis of the KAT search results showed that of 64 keywords used, only 28 were associated with relevant studies, and only 24 keywords would have captured all relevant studies. Additionally, by including keywords relevant to ecological studies, KAT successfully helped prioritize other studies more likely to be relevant to PCB elimination in mammalian species. Thus, KAT identified a highly effective keyword set that can be applied to increase efficiency of future literature searches for chemical half-lives of PCB elimination in humans.

Organochlorines burden in moss H. cupressiforme and topsoil across Serbia.

Following up-to-date initiatives of the Stockholm Convention, its global monitoring plan, and the International Cooperative Programme on Natural Vegetation and Crops (ICP Vegetation 2015) under the convention on long-range transboundary air pollution, this study examined 17 polychlorinated biphenyls (PCBs) and seven organochlorine pesticides (OCPs) in the moss Hypnum cupressiforme Hedw. and topsoil sampled across Serbia. In the topsoil, OCPs ranged from 0.0158 to 9.6804ngg-1 while concentrations of individual PCB congeners were in the range between 0.0185 and 0.3107ngg-1. The levels of OCPs and PCBs in the moss H. cupressiforme ranged from 2.7785 to 23.9501ngg-1, and from 0.4325 to 15.8013ngg-1, respectively. POP relationships between topsoil and moss investigated by fugacity model equations indicated that the moss POP enrichment was a result of atmospheric long-range transport rather than secondary reemissions from soil.

The distribution characteristics of polychlorinated biphenyls (PCBs) in the surface sediments of Ross Sea and Drake Passage, Antarctica: A 192 congeners analysis

A total of 23 sediment samples are collected from Ross Sea and Drake Passage to investigate the distribution characteristics of polychlorinated biphenyls (PCBs) in the Antarctic marine sediments. Over 51 kinds of PCBs are detected through exhaustive searches using multiple reaction monitoring system. The results show that the concentration of individual PCB congener and total PCBs vary greatly among sampling sites, ranging from not detected to 49.75 ng g−1 and 3.77 to 246.86 ng g−1, respectively. The average PCBs level in Ross Sea is ten times higher than that in Drake Passage. Two different homologues, hexa- and tetra-CBs, give high contributions to ∑PCBs level in most samples from Ross Sea and Drake Passage, respectively. Our results support that the marine sediments might be an important sink for PCBs. Besides, the biological pump and the primary productivity might be responsible for the distribution differences of PCBs between Ross Sea and Drake Passage.

Association study between plasma levels of polychlorinated biphenyls and risk of cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) ranks the most lethal skin cancer worldwide. However, other risk factors have been hardly explored, aside from ultraviolet radiation (UVR). Polychlorinated biphenyls (PCBs) were implied to be potential risk factors for CMM, although all the evidence was obtained from the western countries. This study examined the relationships between plasma levels of PCBs and CMM risk adjusting for sun sensitivity and sun exposure in a Chinese population, using a case-control study, including 450 CMM cases and 500 healthy controls. Plasma levels of a total of 33 PCB congeners were assayed in both cases and controls. Our results showed that there was a significant association between total summed PCB level and CMM risk, with a 1.44-fold increased risk for those in the highest quartile compared to those in the lowest quartile (OR = 1.44, 95% CI: 1.02–2.03, P for trend = 0.031). Significantly increased ORs were also observed for individual PCB congeners (PCB52, PCB170 and PCB180). These associations persisted after control for sun sensitivity and sun exposure. Our study represents the first evidence conducted in Asians, and does support the hypothesis that PCB exposure increases CMM risk.