Elevated Levels Of Polychlorinated Biphenyls Research Articles

Metabolic activation of WHO-congeners PCB28, 52, and 101 by human CYP2A6: evidence from in vitro and in vivo experiments.

Despite extensive research on the metabolism of polychlorinated biphenyls (PCBs), knowledge gaps persist regarding their isoform-specific biotransformation pathways. This study aimed to elucidate the role of different cytochrome P450 enzymes in PCB metabolism, focusing on WHO-congeners 2,4,4'-trichlorobiphenyl (PCB28), 2,2',5,5'-tetrachlorobiphenyl (PCB52), and 2,2',4,5,5'-pentachlorobiphenyl (PCB101). Utilizing engineered HEK293 cell lines, we investigated the in vitro metabolism of these PCBs by CYP1A2, CYP2C8, CYP2C9, CYP3A4, CYP2A6, and CYP2E1, revealing robust production of hydroxylated metabolites. Our results show that CYP2A6 plays a major role in the metabolism of these congeners responsible for predominant formation of para-position hydroxylated metabolites, with concentrations reaching up to 1.61µg/L (5,89nM) for PCB28, 316.98µg/L (1,03µM) for PCB52, and 151.1µg/L (441nM) for PCB101 from a 20µM parent PCB concentration. Moreover, concentration-dependent cytotoxic and cytostatic effects induced by reactive intermediates of the PCB hydroxylation pathway were observed in HEK293CYP2A6 cells, for all three congeners tested. CYP2A6 was specifically capable of activating PCBs 28 and 101 to genotoxic metabolites which produced genetic defects which were propagated to subsequent generations, potentially contributing to carcinogenesis. In a clinical study examining CYP2A6 enzyme activity in formerly exposed individuals with elevated internal PCB levels, a participant with increased enzyme activity showed a direct association between the phenotypic activity of CYP2A6 and the metabolism of PCB28, confirming the role of CYP2A6 in the in vivo metabolism of PCB28 also in humans. These results altogether reinforce the concept that CYP2A6 plays a pivotal role in PCB congener metabolism and suggest its significance in human health, particularly in the metabolism of lower chlorinated, volatile PCB congeners.

Occupational exposure to polychlorinated biphenyls: Development of neuropsychological functions over time

Occupational exposure to polychlorinated biphenyls (PCBs) continues to affect the health of exposed individuals until today. This study aims to expand previous findings by examining the development of neuropsychological functions of occupationally exposed participants over time. Especially verbal fluency and sensorimotor processing, found to be impaired in a previous study, were thus of particular interest. A total of 116 participants, who were part of the HELPcB cohort, underwent a neuropsychological test battery covering a multitude of cognitive functions. Plasma PCB levels were determined for each participant and classified as elevated or normal based on comparative values drawn from the German general population. Two structural equation models were then used to examine the effects of elevated PCB levels on neuropsychological functions. Results suggest that participants who displayed increased PCB plasma levels continued to show impairments in verbal fluency but not in sensorimotor processing after a second examination one year after the first measurement. Specifically, low chlorinated PCBs are associated with impaired verbal fluency, as compared to high-chlorinated and dioxin-like congeners. Alteration of dopamine concentration in response to PCB exposure might be a potential explanation of this result.

Evaluation of Polychlorinated Biphenyls in Sediments from Surface Waters of Igodan, Okunmo, Lebi, Idepe and OAUSTECH in Okitipupa, Ondo State Nigeria

The presence of PCBs in water bodies is an emerging issue for water quality. This is because, once PCBs reach a lake or river, they concentrate in the sediments by attaching to the organic matter. Therefore, the objective of this paper is to evaluate the level of polychlorinated biphenyls (PCBs) in sediment from surface waters of Igodan, Okunmo, Lebi, Idepe and Oaustech in Okitipupa, Ondo State Nigeria using appropriate standard methods. Data obtained reveals that in Igodan the concentration of PCBs in sediment w.as PCB 44 (5.42±0.00), PCB 18 (3.04±0.00), PCB 28 (3.27±0.07) and PCB 170 (6.60±0.00). Okunmo PCBs concentration in sediment was PCB 44 (0.67±0.00), PCB 18 (0.03±0.00), PCB 28 (0.32±0.00) and PCB 170 (0.18±0.00). Lebi PCBs concentration in Sediment was PCB 44 (0.82±0.00), PCB 18 (3.96±0.00), PCB 28 (1.12±0.00) and PCB 170 (1.08±0.00). Except for PCB 170 (0.33±0.02), the PCB concentration in sediment from the Idepe and the OAUSTECH were both below the detection limit (BDL). Correlation between Physicochemical Parameters and PCBs homologs shows a negative correlation for the relationship of EC (Electrical Conductivity), TOC (Total Organic Carbon) and pH at ( -0.283), (-0.262) and ( -0.246) respectively. According to multivariate investigation, releases from nearby factories, deterioration of electrical cables and transformers, waste from university laboratories and facilities, as well as diesel residues from lister engines could be associated with the elevated levels of PCBs in sediments collected from the five sampled sites in Ondo State. TriPCBs > tetraPCBs were in this order in which the median concentrations of PCB homologues were found in sediments from the surface water.

Impact of smoking and candle burning on air concentrations of PCB in a PCB contaminated indoor environment

Long-lasting elevated indoor air concentrations of semi-volatile organic compounds (SVOCs) can cause contamination of indoor surface materials because these compounds have physical-chemical properties causing them to be sorbed (and desorbed) from various surfaces in the indoor environment. Due to this material-gas partitioning and the extensive area of surface materials, the surfaces have the potential to counteract changes in gaseous air concentrations by re-emitting or absorbing SVOCs. In the air itself a partitioning between the gaseous and particulate bound SVOCs exists, relying on among other things the amount and characteristics of the particles. The aim of this study was to investigate the impact of increased particle matter in a contaminated environment, i.e. whether an increase in particles would increase the total air concentration of SVOC through a displacement from the gaseous to the particle phase and at the same time a re-establishment of the gaseous concentration caused by desorption from the surface materials. The study was conducted by measuring the gas and particle bound concentration of SVOCs among a range of congeners of polychlorinated biphenyls (PCBs) in indoor air and quantify the influence of an increased concentration of particulate matter. The experiments were conducted in a room within a dwelling that had elevated levels of PCBs for the last five decades. The increased amount of particulate matter was generated by burning candles and cigarettes, which was measured as particle number concentration and size fractions. Increased cigarette particle concentration increased the indoor air concentration of the sum of all congeners measured by almost 70% compared to background level. Particles from candle burning did not have a similarly significant effect, even though their number concentration was higher. This was likely due to the chemical composition of the particles; cigarette smoke consists primarily of organic particles, while the steady burning of candles produces smaller, mainly inorganic particles. The concentrations of 15 PCB congeners were determined and it was observed that their sorption to cigarette smoke increased with increasing chlorination. A partitioning model indicates absorptive behaviour of PCB to cigarette particles. The results show that smoking inside a residence with long-lasting, elevated PCB concentrations can further increase the concentration of PCB in the air due to its interaction with particulate matter.

Upregulation of CCL7, CCL20, CXCL2, IL-1β, IL-6 and MMP-9 in Skin Samples of PCB Exposed Individuals—A Preliminary Study

Polychlorinated biphenyls (PCBs) are well known immunotoxic and carcinogenic compounds. Although cutaneous symptoms are the hallmark of exposure to these compounds, exact pathophysiologic mechanisms are not well understood. We took skin biopsies from moderately high PCB exposed workers (n = 25) after an informed consent and investigated the expression of immunological markers such as CCL-7, CCL-20, CXCL2, IL-1β and IL-6, as well as the matrix metalloproteinase MMP-9, EPGN and NRF2 by RT-qPCR, and compared expression levels with plasma PCB levels. Statistical analyses showed a significant correlation between CCL-20, CXCL2, IL-6, IL-1β, CCL-7 and MMP-9 and PCB serum levels. EPGN and NRF2 were not correlated to PCB levels in the blood. We found a significant correlation of genes involved in autoimmune, auto-inflammatory and carcinogenesis in skin samples of PCB exposed individuals with elevated plasma PCB levels. Confirmation of these findings needs to be performed in bigger study groups and larger gen-sets, including multiple housekeeping genes. Further study needs to be performed to see whether a chronical exposure to these and similar compounds can cause higher incidence of malignancies and inflammatory disease.

Occurrence of Halogenated Organic Pollutants in Hadal Trenches of the Western Pacific Ocean.

The hadal trenches are the most remote and inaccessible habitats on earth and were once believed to be pristine. A recent study has reported the detection of high levels of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), in endemic amphipods from two hadal trenches (Mariana and Kermadec) in the Western Pacific, implicating that the trenches are indeed polluted. However, a fundamental question remains unanswered, if and to what extent such the physical environment of the trenches is polluted by POPs. In this study, we sampled Mariana, Mussau, and New Britain trenches and analyzed samples of amphipods, sediment, and suspended particulate matter (SPM). Our results show that the amphipods contained elevated levels of PCBs and PBDEs, comparable to those reported in the earlier study. We also detected significantly high concentrations (up to 1343 ng g-1 lw) of chlorinated pesticides, such as dichlorodiphenyltrichloroethanes and chlordanes. Furthermore, four brominated natural products (BNPs), which structurally resembled methoxylated brominated diphenyl ethers or polybrominated biphenyls, were identified in the endemic amphipods. However, neither POPs nor BNPs were detected in sediments or SPM. Taken together, we propose that the POPs detected in endemic amphipods likely resulted from bioaccumulation by feeding on polluted large detritus (e.g., carrion) falling to the trench bottoms from the surface ocean.

Levels of PAHs, PCBs, and toxic metals in Ruditapes philippinarum and Donax trunculus in Marmara Sea, Turkey.

The manila clam Ruditapes philippinarum and the wedge clam Donax trunculus are economic bivalve species which constitute an important part of the natural bivalve beds in the Marmara Sea, Turkey. Toxic chemicals such as, dioxins, dioxin-like polychlorinated biphenyls (PCBs), polycyclic hydrocarbons (PAHs), and toxic metals are recognized as important health risk factors that threaten public health via food or directly in the environment. In the present study, we aimed to determine and monitor levels of these toxic chemicals in both clam species, R. philippinarum and D. trunculus, between 2013 and 2017. According to the results, maximum levels of dioxins, PAHs, and toxic metals (lead, cadmium, mercury) during the period were determined as 0.18 pg g-1 , 2.43 mg kg-1 , and 0.44-0.53-0.1 mg kg-1 , respectively. The level of contaminants in both clam species were determined to be below the threshold or tolerable daily intake values established by the European Commission, European Food Safety Authority (EFSA), and Food and Agriculture Organization/World Health Organization (FAO/WHO). Seasonal fluctuations were observed to be similar in both species and also in seasons, but elevated levels of PCBs and PAHs were detected in warmer months during the period. As a consequence, toxic chemicals in both clam species were found at low concentrations in this study from the point of view of public health concerns; however, the contaminants should be closely monitored in the future due to their elevated levels in samples. © 2020 Society of Chemical Industry.

SAT-723 Effects of Organohalogenated Endocrine Disrupting Chemicals on Cell Proliferation and Gene Expression in GH3 Somatolactotropes

Endocrine Disrupting Chemicals (EDCs) are substances that have been increasingly implicated in many serious pathologies, such as tumor formation, metabolic, growth and reproductive disorders. The economic and health burden of exposure to these compounds has an annual predicted cost in excess of €150 billion, across the EU regions alone. Of the growing list of compounds that act as EDCs, the organohalogenated compounds (OHCs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) have been associated with an increased risk of pituitary disease. We have previously reported that feline patients with hypersomatotropism (acromegaly) are exposed to elevated levels of PBDEs and PCBs in their environment. However, the mechanisms by which these compounds might directly influence somatotroph function have yet to be established. In this study, we use the GH3 rat somatolactotrope cell line to investigate how two PCB congeners - 138 and 153 - influence cell proliferation (using a Crystal Violet assay) and somatotrope gene expression (using a multiplex RT-qPCR approach to examine expression of Esr1, Esr2, Sstr1, Sstr2, Sstr3, Sstr4, Sstr5, Insr, Tshr, Pou1f1, Ghrhr2, Gh). GH3 cells were treated with Phenol Red-free media in the absence or presence of either PCB138 or 153 (-10 to -6 M), or in combination (-10 to -6M) for up to 72h. Treatment with either PCB alone, or in combination, caused significant concentration-dependent, biphasic changes in cell proliferation at each time point, but with a different profile of response on each day (significantly increased at high pM/low nM concentrations); there was no evidence of toxicity at maximum concentrations (-6M). Gene expression changes were determined in GH3 cells treated in the absence or presence of either -8M or -6M PCB138 or 153 for 24h. Differential effects of these compounds were seen on the expression of Sstr3, Sstr4, Sstr5 and Insr; all other gene transcripts were unaffected. These findings reveal that GH3 cells exposed to physiologically relevant concentrations of PCB138 and 153, alone or in combination, show concentration-dependent increases in cell proliferation; furthermore, the expression of genes associated with therapeutic targets for the treatment of acromegaly (i.e. SSTRs) are differentially affected by exposure to PCB138 and 153. Our data indicate a potential mechanism for EDCs in the onset of acromegaly, that require further, in vivo, investigations.

Informal e-waste recycling and plasma levels of non-dioxin-like polychlorinated biphenyls (NDL-PCBs) – A cross-sectional study at Agbogbloshie, Ghana

Informal e-waste recycling leads to a contamination of the workers with several hazardous substances, in particular heavy metals and persistent organic pollutants (POPs). Polychlorinated biphenyls (PCBs) belong to the group of POPs and are suspected to be associated with adverse health effects. In particular lower chlorinated PCBs, such as the congeners PCB 28 and PCB 52 are a marker of occupational exposure. The aim of our study was to assess the occupational PCB exposure in e-waste workers in relation to their specific recycling task (e.g. dismantling, burning). Altogether, n = 88 e-waste workers and n = 196 control subjects have been included in this study. All plasma participant's samples were evaluated for the PCB congeners PCB 28, 52, 101, 138, 153, 180 and sum of NDL-indicator congeners by human biomonitoring. A significant difference could be detected for the lower chlorinated PCB congeners (PCB 28, 52, and 101) for e-waste workers in comparison to the control group. Analyzing specific recycling tasks, workers who dismantle and those who burn e-waste showed the highest plasma levels of PCB 28 and 52. In conclusion, e-waste workers showed occupational related elevated PCB levels. Although those levels did not exceed the BAT value, workers were contaminated with PCBs during their task. Occupational health and safety measure are therefore necessary to protect the worker's health.

PCBs in Older Buildings: Measuring PCB Levels in Caulk and Window Glazing Materials in Older Buildings.

A method for the determination of polychlorinated biphenyls (PCBs) in caulk and glazing materials was developed and evaluated by application to a combination of 36 samples of caulk and glazing materials, from four schools in the northeastern area of the United States. Quality control analysis showed a range of 45 to 170% for spike recovery from the various samples and a range of 10.9 to 20.1% difference in precision among replicates. The result for the samples analyzed showed that three of the four schools sampled contained caulking and glazing materials with levels of PCBs >50 μg/g (range 54.6 μg/g to 445,000 μg/g). Across the four schools, 24% of collected caulk and glazing samples contained elevated PCB levels relative to the U.S. Environmental Protection Agency’s (EPA) bulk product waste criterion of 50 μg/g under “The Frank R. Lautenberg Chemical Safety for the 21st Century Act.” The PCBs determined in the samples, exhibited characteristic chromatographic patterns similar to those of Aroclors 1242, 1248, 1254, 1260, 1262, and a 1016/1254 mix.

Bioaccumulation and cycling of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in three mangrove reserves of south China

Total 22 organochlorine pesticides (OCPs) compounds and 31 polychlorinated biphenyls (PCBs) congeners in mangrove sediments and tissues (leaf, branch, root and fruit) of nine species from three Mangrove Reserves of China were studied. The mean concentrations of total DDTs, HCHs, OCPs and PCBs in sediments were 2.84, 0.06, 3.84 and 0.17 ng g−1 dw, while those in tissues were 1.85, 0.22, 9.43 and 1.61 ng g−1 dw, respectively. The elevated OCPs and PCBs levels in mangrove leaves may be caused by atmospheric sedimentation. The biota sediment accumulation factor (BSAF) values of both OCPs (mean: 3.4) and PCBs (mean: 9.9) are generally larger than one, implying mangroves' bioaccumulation and their ability to intercept pollutants. The BSAFs of PCBs in mangrove tissues were negatively correlated with the PCB congener's octanol-water partition coefficients (KOW, R = 0.58, n = 31, p < 0.001), suggesting that lower chlorinated CB congeners are more bioaccumulative in mangroves. In order to better understanding the fate of these organochlorine compounds, the cycling (including the standing accumulation, the annual absorption, the annual net retention, the annual return, and the turnover period) of OCPs and PCBs in the Mangrove Reserves were estimated, and the results indicated that mangroves are playing important roles in retaining OCPs and PCBs.

Expression of CYP1A1, CYP1B1 and IL-1β in PBMCs and skin samples of PCB exposed individuals

Polychlorinated biphenyls (PCBs) are well- known man-made persistent environmental pollutants and endocrine disruptors. As a result of mass production in the past, background levels of these compounds can be measured in human blood worldwide.In 2010 high internal levels of PCBs were discovered in workers of a transformer-recycling company in Germany. Our aim was to measure, whether the expression of CYP1A1, CYP1B1, and IL-1β is dysregulated in peripheral blood mononuclear cells (PBMCs) of the exposed individuals (n = max 308). Further, we measured the regulation of CYP1A1, CYP1B1, AHRR (aromatic hydrocarbon receptor repressor) and IL-1β in skin samples of 25 workers with elevated plasma PCB levels using quantitative PCR (q-RT-PCR).We found a significant correlation between the regulation of IL-1β in skin samples and lipid adjusted PCB levels. In the PBMCs, the expression levels of CYP1A1, CYP1B1 and IL-1β decreased over time with decreasing PCB plasma levels.The upregulation of the cytokine IL-1β in exposed individuals with higher PCB plasma levels warrants further investigation in order to examine its role in the pathophysiology of autoimmune disorders and tumor promotion.

Polychlorinated biphenyls in the surrounding of an e-waste recycling facility in North-Rhine Westphalia: Levels in plants and dusts, spatial distribution, homologue pattern and source identification using the combination of plants and wind direction data

During this study the occurrence of polychlorinated biphenyls (PCBs) in the surrounding of an e-waste recycling facility in North-Rhine Westphalia was analysed. PCB levels were analysed in curly kale, spruce needles, street dusts and dusts. Conspicuously high PCB concentrations in curly kale and spruce needles were found directly northwards of the industrial premises. Furthermore a concentration gradient originating from the industrial premises to the residential areas in direction southwest to northeast was evident. Homologue patterns of highly PCB contaminated dusts and street dusts were comparable to the homologue patterns of PCB in curly kale and spruce needles. This corroborates the suspicion that the activities at the e-waste recycling facility were responsible for the elevated PCB levels in curly kale and spruce needles. The utilization of multiple linear regression of wind direction data and analysed PCB concentrations in spruce needles proved that the e-waste recycling facility caused the PCB emissions to the surrounding. Additionally, this evaluation enabled the calculation of source specific accumulation constants for certain parts of the facility. Consequently the different facility parts contribute with different impacts to the PCB levels in bioindicators.

Polychlorinated biphenyls and their hydroxylated metabolites in the serum of e-waste dismantling workers from eastern China.

A number of studies have reported on the exposure of e-waste dismantling workers to significantly high concentrations of halogenated organic pollutants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers. Such exposure can have adverse health effects. However, little information on the metabolites of these contaminants exists. In this study, we investigated PCBs levels and their hydroxylated metabolites (OH-PCB) in the serum of e-waste workers in Taizhou in eastern China. Our results indicate elevated PCB and OH-PCB levels in the serum of the workers, with medians of 443.7 and 133.9ng/glw, respectively. Tri- to hexachlorinated PCB congeners were the dominant homologue groups in all of the samples. 4-OH-CB107 was the predominant homologue among the hydroxylated metabolites, accounting for 88.9% of the total OH-PCB concentrations. While dietary sources (e.g., fish) appear to be an important route for PCB accumulation in non-occupational exposure groups, exposure via ingestion of house dust and inhalation of pollutants derived from the recycling of PCB-containing e-wastes may primarily contribute to the high body burden observed in the occupational groups. Since we found concentrations of metabolites higher than those of their parent compounds, further studies need to pay more attention to their bioaccumulation and toxicity.

Can Indicator Congeners be used to Estimate the Total Burden of Polychlorinated Biphenyls (PCB) in Human Blood after Exposure through Indoor Air?

Introduction: For Human Biomonitoring (HBM) regularly PCB 138, 153 and 180 are analyzed in blood samples. The German “HBM Commission” assumes that the sum of the concentrations of these 3 indicator congeners multiplied by 2 represents the total PCB burden. This norm is based on data taken from exposure studies after dietary intake. Data from indoor air shows a different congener pattern, which might lead to a relatively higher intake of lower chlorinated PCBs. We analyzed the concentrations of all 209 congeners in blood samples from employees exposed to elevated PCB indoor air levels. We examined whether the 3 indicators would also represent 50 % of the PCB burden if relevant exposure comes from indoor air. Methods: Blood samples were collected from 44 adults working in buildings with elevated PCB levels in indoor air. Intervening exposure variables and time budgets were evaluated by questionnaires. The samples were analyzed by HRGC/HRMS, which allows quantifying 141 individual congeners. Others could only be co-eluted. Therefore in total 172 results per blood sample could be reported. Results: 63 different congeners could be quantified in each sample, another 96 congeners in at least one. Most relevant were PCB 153 and the co-eluted pairs 189/193 and 138/160. To 14 others relevant shares (&gt; 1%) could be attributed. The median relative contribution of the indicator congeners was 49%. 4 samples showed higher percentages than 55% and in 8 samples the indicator PCBs shared less than 45% of the burden. Total PCB, calculated by multiplying the sum of the indicator congeners by 2, showed a strong correlation to the sum of all 209 measured congeners for each sample (r: 0,979). Adding 3 more indicator congeners performed only slightly better. Conclusion: The norm issued by the German “HBM Commission” to calculate the total PCB burden on the base of 3 indicator congeners leads to quite good results, and can also be used for individuals exposed mainly by indoor air.

Polychlorinated biphenyls (PCBs): impact on bat activity and foraging behaviour along the upper Hudson River, New York

Sediments of the upper Hudson River, New York, USA, contain polychlorinated biphenyls (PCBs). Consequently, elevated levels of PCBs have been found in the tissues of bats and their insect prey along this region. However, it is not clear whether bat activity and foraging behaviour have been affected. To assess possible effects of PCBs on bat activity and foraging behaviour, we measured the activity of little brown bats (Myotis lucifugus (LeConte, 1831)) and hoary bats (Lasiurus cinereus (Palisot de Beauvois, 1796)) along the upper Hudson River, as well as abundance of insect prey at the same locations. We also measured foraging duration and distances travelled by radio-tagged M. lucifugus. We found that bat activity and insect abundance did not differ with PCB concentration. We did, however, find that foraging behaviour along the Hudson River differed from a control site. Specifically, M. lucifugus foraging along PCB-contaminated areas of the Hudson River travelled shorter distances from their roosts and spent less time foraging than bats at an uncontaminated site. Our results show that while bats roost and forage in areas historically exposed to PCBs, this exposure has not adversely affected bat activity, foraging behaviour, or abundance of insect prey.

Persistent halogenated compounds in fish from rivers in the Pearl River Delta, South China: Geographical pattern and implications for anthropogenic effects on the environment

Three fish species, mud carp (Cirrhinus molitorella), tilapia (Tilapia nilotica), and plecostomus (Hypostomus plecostomus), from rivers in the Pearl River Delta (PRD) were analyzed for dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and Dechlorane Plus (DP). The concentrations of DDTs, HCHs, PCBs, PBDEs, DBDPE, and DP ranged from 380–57,000, 5.5–100, 30–4200, 6.9–690, 0.29–460, and 0.09–20ng/g lipid weight, respectively. Congener profiles or chemical compositions of PBDEs, DPs, DDTs, and HCHs in plecostomus differed significantly from those in the other two fish species, which can be ascribed to species-specific metabolism. DDTs derived from historical residue and land erosion remained the predominant pollutants in the PRD, while industrial and urban activities resulted in elevated levels of PCBs and PBDEs in the metropolitan area. E-waste recycling activities have greatly impacted on the adjacent aquatic environment, and the potential point source for DBDPE was also revealed.

PCBs and DDTs in light-vented bulbuls from Guangdong Province, South China: Levels, geographical pattern and risk assessment

Thirty-two light-vented bulbuls (Pycnonotus sinensis) were collected from six sampling sites in Guangdong Province, South China to investigate the geographical variation on the occurrence of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs). Concentrations of PCBs and DDTs in the pectoral muscle of light-vented bulbul ranged from 140 to 73,000ng/g lipid weight (lw) and 12 to 4600ng/g lw, respectively. PCB concentrations were significantly higher in birds from e-waste site compared to other sampling sites (mean, 18,000 vs 290ng/g lw, p<0.0001), implying that PCBs mainly came from e-waste recycling activities. No significant differences for DDT levels were observed among the sampling sites (p=0.092). Differences in PCB homologue profiles among the sampling sites were found and can be probably ascribed to different local contamination sources. p,p′-DDE (>80%) was the most abundant component of DDTs in birds. Compositional pattern of DDTs suggested that historical residue was the main source of DDT. The toxic equivalent (TEQ) concentrations had significant positive correlations with PCB concentrations, indicating that elevated PCB levels may have adverse effects on light-vented bulbuls.

Distribution and risk assessment of polychlorinated biphenyls (PCBs) in the remote air and soil of Manipur, India

∑25PCB congeners including dioxin-like compounds were analyzed at three sites of Manipur India to assess the level of polychlorinated biphenyls (PCBs) in air and soil. The ∑25PCBs were higher in urban air (average 2,454 pg/m3), followed by the mountain air (average 2,109 pg/m3) and rural air (average 1,756 pg/m3). PCB levels observed in urban air were higher compared to PCB levels reported in major Indian metropolitan cities especially along the coastal region and were comparable with the pristine sites of India and also with some pockets of China and Europe. The heavier congeners (tetra, penta, tri and hexa) were dominant in both air and soil samples and show significant correlation with the ambient temperature. Emission of PCB congeners was investigated from soil surface. The total organic carbon present in soil shows the significant correlation (r 2 = 0.8; p < 0.05) with the PCBs could indicate that the PCBs originated from the similar sources. Principal component analysis revealed that the sources of higher chlorinated PCB congeners are local emissions while long-range atmospheric transport process is responsible behind elevated levels of lower chlorinated PCBs. Total calculated toxic equivalent (TEQ) levels in soil (37.17–160.5 pg/g) were superior to reported TEQ level of agricultural soil in Delhi, India (0.01–105.40 pg/g). Back trajectory analysis showed that the observed high levels of PCB at Manipur may due to movement of air masses, mostly from the Northern and Southern India and to some extent from Myanmar.

Persistent organic pollutants in benthic and pelagic organisms off Adélie Land, Antarctica

The concentrations of polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and polybrominated diphenylethers (PBDE) were described in benthic and pelagic species collected off Adélie Land, Antarctica. Strong differences were observed among species, with reduced PeCB and HCB levels in benthic species, and elevated PCB levels in the Antarctic yellowbelly rockcod, the Antarctic sea urchin and the snow petrel. Lower-chlorinated congeners were predominant in krill; penta-PCBs in benthic organisms; hexa- and hepta-PCBs in seabirds and cryopelagic fish. This segregation may result from sedimentation process, specific accumulation and excretion, and/or biotransformation processes. The presence of PBDEs in Antarctic coastal organisms may originate from atmospheric transport and partly from a contamination by local sources. Although POP levels in Antarctic marine organisms were substantially lower than in Arctic and temperate organisms, very little is known about their toxic effects on these cold-adapted species, with high degree of endemism.