Polychlorinated Biphenyls Composition Research Articles

Assessment of the Pollution Levels, Sources, and Exposure Risks of Polychlorinated Biphenyls (PCBs) in Urban Park Dusts within Lagos Metropolis

ABSTRACTPolychlorinated Biphenyls (PCBs) represent organic contaminants that are persistent hazardous, carcinogenic, and genotoxic, thereby endangering both human well‐being and the ecosystem. This research delved into concentration patterns, sources, and health hazards associated with PCBs in dust collected from vehicle parks in Lagos metropolis. PCBs in samples of Lagos park dust extended from 1.00 to 36.80 ng/g, with PCB 18 exhibiting the highest mean concentration of 17.02 ng/g. Among the 12 PCBs studied, 5 Cl atom PCBs contributed the highest percentage, constituting 30% of the total PCB content in Lagos park dust. Dioxin‐like PCBs (DLPCBs) made up 27% of the overall PCBs composition in the dust. Using the positive matrix factorization method, eight sources of PCBs were identified, with biomass combustion contributing the highest proportion at 42% of the total PCB emissions. Health risk estimates revealed that the magnitude of PCBs exposure in human followed the order: ingestion > dermal contact > inhalation. PCBs exposure through ingestion in children was 9.33 times higher than that of adults, potentially attributed to the inadvertent intake of dust particles by children via hand‐to‐mouth contact. Cancer risk assessments for all PCB congeners remained below 10−6, indicating acceptable risk levels. PCB 18 had the highest cancer risk values, reaching 8.69 × 10−9 for children and 1.19 × 10−9 for adults.

Persistent Organic Pollutants and Suspended Particulate Matter in Snow of Eastern Siberia in 2009-2023: Temporal Trends and Effects of Meteorological Factors and Recultivation Activities at Former Industrial Area.

Suspended particulate matter (SPM), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCP) were studied in the snow cover at urban and suburban localities in the Irkutsk region, Eastern Siberia for their temporal variations in 2009-2023, daily deposition fluxes (DDFs), and effects of some meteorological factors, as well as the effects of different technogenic activities in the industrial area of the former organochlorine enterprises of Usol'ekhimprom. SPM loads at both stations were found to be at a low level of pollution. The levels of HCB, α + γ-HCH, and ∑p,p'-DDX were lower than Russian maximum permissible levels (MPLs) in drinking water, groundwater, and surface water for household drinking and cultural purposes. The sums of all organochlorine compounds studied in snow were higher than the MPL in freshwater water bodies for fishery purposes. The levels of the DDFs of HCHs, DDTs, and heptachlorinated PCB decreased, di- and trichlorinated PCB levels increased, and HCB levels changed at a polynomial line during 2009-2023. The change in the relative composition of PCBs was found as a result of recultivation activities at the industrial area of the former organochlorine enterprise of Usol'ekhimprom. The air humidity and temperature are the key meteorological factors affecting the DDFs of PCBs and OCPs.

Spatiotemporal distribution, source analysis and ecological risk assessment of polychlorinated biphenyls (PCBs) in the Bohai Bay, China

As a class of persistent organic pollutants (POPs), the spatial and temporal distribution of polychlorinated biphenyls (PCBs) in seawater is important for environmental assessment. Surface water samples were collected from 35 stations during summer and 36 stations during autumn of 2020 in the Bohai Bay. The concentration, composition, distribution and sources of PCBs were analyzed to assess the ecological impact of PCBs. The average concentration of ∑18PCBs was 124.6 ng/L (range of 28.1–445.5 ng/L) in summer and 122.8 ng/L (range of 21.0–581.4 ng/L) in autumn. PCBs in surface seawater of the Bohai Bay showed high near-shore and low far-shore characteristics, indicating the serious influence of land-based sources such as port activities and river inputs. Proportion analysis showed that Tetra-PCBs and Penta-PCBs were the major constituents in most stations. It was assessed as moderate and high risk (MRQ > 0.1) by mixture risk quotient (MRQ) and concentration addition (CA) model in surface seawater of the Bohai Bay. Principal component analysis (PCA) was used to explain the sources of PCBs in the Bohai Bay. PCBs in the Bohai Bay may come from commercial PCBs and their incineration products, municipal landfills, wood and coal combustion, and industrial activities, etc.

Polychlorinated biphenyls (PCBs) in intertidal sediment and water from Lagos lagoon: Baseline report on occurrence, distribution and ecotoxicological risk assessment

To assess the occurrence and potential ecological risk associated with organic micropollutants in Lagos lagoon, 27 polychlorinated biphenyls (PCBs) were analysed in sediments and surface water. Sediment samples were obtained from 18 designated sites (SD1 – SD18) using a Van Veen grab sampler and extracted following standard procedures. Cleaned extracts were analysed using gas chromatography with electron capture detector (ECD). The concentration of ∑PCBs in sediment samples ranged between 6757.61 and 273.46 µg/kg. The PCB homologues distribution patterns in sediments indicated that the low-chlorinated (∑di-PCB - ∑penta-PCB) PCBs were more dominant with 61.1 % occurrence than the high-chlorinated ((∑hexa-PCB - ∑nona-PCB) PCBs with 38.9 % relative abundance. The following is the decreasing order of the average homologue composition of PCBs in sediment samples: ∑tetra-PCB (24.6%) > ∑octa-PCB (21 %) > ∑hexa-PCB (13.8 %) > ∑penta-PCB (12.8) > ∑tri-PCB (11.4 %) > ∑hepta-PCB (7.8 %) > ∑nona-PCB (4.9 %) > ∑di-PCB (2.9 %). More so, the ∑PCBs in surface water samples ranged from 69.28 to 440.90 ng/L, with the mean ranging between 7.21 and 16.33 ng/L. The class distribution of PCB homologue profiles in water samples indicated that highly-chlorinated (∑hexa-PCB to ∑nona-PCB) PCBs were the dominant homologues, with 94.4 % occurrence, compared to the very low occurrence rate (5.6 %) of the low-chlorinated (∑di-PCB to ∑penta-PCB) PCBs. Hexa-PCBs (PCB-138 and PCB-153) were the dominant congeners in most water samples. The concentrations of ∑PCBs in sediments and surface water were unprecedentedly high at almost all locations. The total toxicity equivalent concentrations (TTECs) of dioxin-like PCBs for the sediment samples ranged from 0.001 to 2.43 µg/kg, with an average of 0.34 µg/kg. These findings suggest that PCB congeners are pervasive from anthropogenic point sources of pollution. Intensive site-specific monitoring and remediation are recommended.

Polychlorinated biphenyls and organochlorine pesticides in surface sediments from river networks, South Korea: Spatial distribution, source identification, and ecological risks.

In this study, the nationwide monitoring of 65 polychlorinated biphenyls (PCBs) and 23 organochlorine pesticides (OCPs) in surface sediments was conducted at 77 sites in river networks in South Korea. The concentrations of ∑PCBs were relatively high in industrial sites (0.0297-138 ng/g dry weight (dw); mean 15.1 ng/g dw; median 5.44 ng/g dw), followed by industrial and agricultural (not detected (ND)-15.2 ng/g dw; mean 1.23 ng/g dw; median 0.513 ng/g dw), other sites (0.0369-0.209 ng/g dw; mean 0.116 ng/g dw; median 0.101 ng/g dw), and agricultural (0.0119-0.359 ng/g dw; mean 0.117 ng/g dw; median 0.0476 ng/g dw). The distribution and composition of PCBs in sediments are affected by past use of commercial products, atmospheric deposition, wastewater effluents, and manufacturing processes. The concentrations of ∑OCPs in industrial sites ranged from 0.0587 to 8.70 ng/g dw (mean 1.85 ng/g dw; median 0.989 ng/g dw), followed by industrial and agricultural (ND-8.54 ng/g dw; mean 0.739 ng/g dw; median 0.343 ng/g dw), other sites (0.0247-0.143 ng/g dw; mean 0.0939 ng/g dw; median 0.114 ng/g dw), and agricultural (0.00838-0.931 ng/g dw; mean 0.232 ng/g dw; median 0.0752 ng/g dw). Hexachlorobenzene and pentachlorobenzene are unintentionally generated in industries and combustion processes. Dichlorodiphenyltrichloroethanes and chlordane were dominantly distributed by historical use, whereas recent inputs (i.e., long-range transport and atmospheric deposition) were related to aldrin, heptachlor, and hexachlorocyclohexanes. The ecological risks determined by the sediment quality guidelines and mean probable effect level quotients were acceptable, except at two sites.

Sedimentary records of persistent organic pollutants (OCPs and PCBs) in Ngoring Lake, the central Tibetan Plateau, China: Impacts of westerly atmospheric transport and cryospheric melting

Lake sediments in remote alpine regions are used to infer information on persistent organic pollutants (POPs) delivery via long-range atmospheric transport (LRAT) with limited influences from local sources. When studying the deposition history of POPs on the Tibetan Plateau, regions influenced by westerly air mass flow have received insufficient attention compared with regions governed by the monsoon. Herein, we collected and dated two sediment cores from Ngoring Lake to reconstruct the depositional time trends of 24 organochlorine pesticides (OCPs) and 40 polychlorinated biphenyls (PCBs) and assess the response to emission reductions and climate change. DDTs, HCHs, hexachlorobenzene (HCB), and PCBs were all detected in the sediment core at low concentrations of 110–600, 4.3–400, 8.1–60, and 3.3–71 pg/g, respectively. The composition of PCBs, DDTs, and HCHs was dominated by congeners with 3 and 4 chlorines (avg. 70 %), p,p’-DDT (avg. 90 %), and β-HCH (avg. 70 %), respectively, indicating the influence of LRAT and the contribution of technical DDT and technical HCH from potential source regions. Temporal trends of PCB concentrations normalized by total organic carbon echoed the peak of global emissions of PCBs around 1970. The rising trend of concentrations of β-HCH and DDTs after the 1960s in sediments was mainly explained by the input of contaminants with melting ice and snow from a cryosphere shrinking under global warming. This study verifies that westerly air mass flow brings fewer contaminants to the lacustrine environment on the Tibetan Plateau than the monsoon and demonstrates the impacts of climate change on the secondary emission of POPs from the cryosphere to the sediments.

Distribution, composition and risk assessment of PAHs and PCBs in cryospheric watersheds of the eastern Tibetan Plateau

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are significant components of persistent organic pollutants (POPs) and pose a threat to both ecosystems and human health. To explore their spatial distribution, origins, and risk assessment, we collected 25 glacial meltwater and downstream river water samples in the eastern Tibetan Plateau (including the Qilian Mountains in the northeast) during the summer of 2022 (June–July). Our results showed that ∑PAHs and ∑PCBs were present in a wide range from ND-1380 ng/L and ND-1421 ng/L, respectively. Compared to other studies worldwide, the ∑PAHs and ∑PCBs in the Hengduan Mountains were at high levels. The PAHs and PCBs mainly consisted of low-molecular-weight homologs, including Ace, Flu, Phe, and PCB52. Phe was the primary component of PAHs. Glacial meltwater samples generally exhibited low concentration of PAHs and PCB52, whereas downstream river water samples typically showed high concentration of PAHs and PCB52. We attributed this characteristic to the influence of pollutants physicochemical properties, altitude effect, long-range transport (LRT), and local environmental conditions. In the eastern Tibetan Plateau glacier basin (especially in the Hailuogou watersheds), the concentration of PAHs and PCB52 in runoff generally increased with decreasing elevation. We believe that the primary factor affecting the concentration of PAHs and PCB52 in the region is the difference in local human activity inputs from various altitudes. The composition characteristics of PAHs and PCBs suggested that incomplete coal combustion and coking discharge mainly caused PAHs, while the combustion of coal and charcoal and the release of capacitors primarily caused PCBs. We assessed the carcinogenic risk of PAHs and PCBs in the glacier basin of the TP and found that the potential threat of PAHs was stronger than that of PCBs. Overall, this study provides new insights into the ecological security of water resources in eastern Tibetan Plateau. It is significant for controlling PAHs and PCBs emissions, assessing the ecological environment of the glacier watershed, and regional human health.

Spatial characteristics, sources and exposure risk of polychlorinated biphenyls in dusts and soils from an urban environment in the Niger Delta of Nigeria

Chlorinated organic compounds, such as polychlorinated biphenyls (PCBs), are a threat to both humans and the environment because of their toxicity, persistence, and capacity for long-range atmospheric transport. The concentrations of 28 PCB congeners, including 12 dioxin-like and seven indicator PCBs, were investigated in soils, and indoor and outdoor dusts from Port Harcourt city, Nigeria, in order to evaluate the characteristic distribution patterns in these media, their sources, and possible risk. The PCB concentrations varied from 4.59 to 116 ng g−1 for soils, and from 1.80 to 23.0 ng g−1 and 2.73 to 57.4 ng g−1 for indoor and outdoor dusts respectively. The sequence of PCB concentrations in these matrices was soil > outdoor dust > indoor dust. The composition of PCBs in these matrices indicated the prevalence of lower chlorinated PCBs in indoor and outdoor dusts, while the higher chlorinated congeners were dominant in soils. Di-PCBs were the predominant homologues in indoor dusts, while deca-PCBs were the most prevalent homologues in outdoor dusts and soils. The TEQ values of dioxin-like PCBs in 60 % of the soils, 100 % of the indoor dust, and 30 % of the outdoor dust were above the indicative value of 4 pg TEQ g−1 established by the Canadian authority. The hazard index (HI) values for exposure of adults and children to PCBs in these media were mostly greater than one, while the total cancer risk (TCR) values exceeded the acceptable risk value of 10−6, which indicate probable non-carcinogenic and carcinogenic risks resulting from exposure to PCBs in these media. Source analysis for PCBs in these matrices shows that they originated from diverse sources.

The derivation of soil generic assessment criteria for polychlorinated biphenyls under the agricultural land scenario in Pearl and Yangtze River Delta regions, China

The agricultural soils in China are suffered from serious polychlorinated biphenyls (PCBs) contamination, however, the valid management standards for farmland are absent to efficiently control the health risks of PCBs exposure. This study analyzed the contamination characteristics and main composition of PCBs in agricultural soils of the southeastern China from the published literature over the past 20 years, and derived the regional generic assessment criteria (GAC) using an exposure modelling approach for individual and total PCBs (∑PCBs) via multiple exposure pathways such as ingestion of soil and dust, consumption of vegetables, dermal contact with soil and dust, ingestion of soil attached to vegetables, and inhalation of soil vapour and soil-derived dust outdoors under the agricultural land scenario. It is identified that the averaged ∑PCBs concentration of 80.03 ng g−1 under the 95 % lower confidence limit with an unacceptable health risk of 4.8 × 10−6 has significantly exceeded the integrated generic assessment criteria (expressed as GACint) of 16.5 ng g−1. Accordingly, the exposure pathways from the consumption of agricultural produces and indirect ingestion of soil attached to vegetables contributed up to 62 %–88 % of the total exposure, followed by 11 %–33 % of the soil ingestion and 2 %–6 % of dermal contact. The derived GACint for ∑PCBs is extremely valuable to effectively assess and manage the PCBs contamination in agricultural soils of China.

Persistent Organic Pollutants (POPs) in Sardine (Sardinella brasiliensis): Biomonitoring and Potential Human Health Effects.

Organochloride (OC) and polychlorinated biphenyl (PCB) concentrations were determined in the muscle tissue of fifty sardine samples (Sardinella brasiliensis) sampled off the south-east Brazilian shelf. The aim herein was to investigate OCs and PCBs composition profile, bioaccumulation potential and human risks. The concentrations of 18 organochlorine pesticides (OCPs) were below the method limit of quantification in most samples (ca. 94%), with few detected, namely δ-HCH, γ-HCH, Endosulfan I and II, Endosulfan Sulphate, DDE, Dieldrin, Endrin, Endrin Aldeide, Endrin Cetone and Metoxyclor. The median concentration for the Σ41 PCBs was 2.32 ng g-1, ranging from values below the limit of quantification (<LOQ) to 37.2 ng g-1. Based on the analyzed samples, the concentrations reported herein do not represent a risk for human consumption according to both national and international guidelines, nor do OC and PCB bioaccumulation in sardines appear to be a concern at the moment. These findings, although preliminary, represent a baseline for future comparisons of the quality of an important source of protein available to the poorest Brazilian population strata.

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.

Ecosystem impact and dietary exposure of polychlorinated biphenyls (PCBs) and heavy metals in Chinese mitten crabs (Eriocheir sinensis) and their farming areas in Jiangsu, China

This study investigated the presence of 18 dioxin-like and non-dioxin-like polychlorinated biphenyls (dl- and ndl-PCBs), heavy metals (Cd, Hg, Pb, and As) in Chinese mitten crabs (Eriocheir sinensis) and their distribution in Jiangsu, China. Risk assessment and source apportionment were employed for evaluating the eco-toxicological impact and human exposure. It was found that the compositions of PCBs varied spatially, suggesting different sources of pollutants, whilst PCB 28, 105, 114, and 126 were consistently found in all sample types, suggesting a common pollution source remained, and the bio-accumulation process was in effect. The total PCBs in sediment were found much higher than in water, and brown meat had the highest and most diverse PCB congeners among all tissues. The presence of heavy metals was found in all samples in descending order of As>Cd>Pb>Hg and in the order of shell>brown meat>white meat>gill for crabs. The results of risk assessment indicated that the potential carcinogenic and non-carcinogenic risks were within the acceptable range for long-term consumption of the crabs overall. However, the highest toxic equivalent (TEQ), carcinogenic, and non-carcinogenic risks were all recorded in Location C, where dl-PCB 126, 169, and As contributed to the majority of the risks. The ecological risk posed by all HMs was low, but cases of serious point source pollution have been found in the investigated regions, and risks caused by Cd individually should raise concerns. Source apportionment study revealed that the contaminants mostly originated from anthropogenic activities. Natural deposition and transportation played an important role as well.

Spatial characteristics, sources, and ecological and human health risks of polychlorinated biphenyls in sediments from some river systems in the Niger Delta, Nigeria

Polychlorinated biphenyls (PCBs) were quantified in sediments from the lower reaches of the Niger, Ase and Forcados Rivers in Nigeria with the aim of elucidating the sources, spatial characteristics and likely ecological and human health risks relating to exposure to PCBs in the sediments. A total of 28 PCB congeners, including 7 indicator PCBs and 12 dioxin-like PCBs, were identified and quantified after Soxhlet extraction with acetone/n-hexane/dichloromethane by gas chromatography–mass spectrometry. The Σ28 PCB concentrations in sediments from the Niger, Ase and Forcados Rivers ranged from 13.5 to 277 ng g−1, not detected to 1633 ng g−1 and 6.9 to 78.6 ng g−1 respectively. The PCB composition in sediments from these three rivers indicate the dominance of lower chlorinated (2-Cl to 5-Cl) congeners over higher chlorinated (6-Cl to 10-Cl) congeners. The ecological and human health risk assessment suggests potential risks for exposure of both organisms and humans to PCBs in sediments from these three river systems.

Carcinogenic and teratogenic status of human population and polychlorinated biphenyls contaminations of soils and biota (European pied flycatcher) in a Perm (Western Ural, Russia).

Polychlorinated biphenyls (PCBs) are included in the persistent organic pollutants designated by the Stockholm Convention and are hazardous compounds both for the environment and public health. The aim of this study was to determine the level of environmental pollution of PCBs in the Perm, in soil and biota (European pied flycatcher), and to analyze whether its presence was the cause of cancer and congenital malformations in the population. Soils in the study area had PCB concentrations of 101.87µg/kg in the Industrialniy District and 27.81µg/kg in the Leninskiy District of the Perm in 2005. The chemical composition of the individual PCBs and PCB groups were the same in the soils of both regions. The blood of nestlings of the European pied flycatcher raised in the Industrialniy District contained 9.61ng PCB/ml, while those in the Leninskiy District had 5.64ng PCB/ml in 2005. A linear correlation was established between the PCB contamination of soils and PCB contamination of pied flycatcher nestling's blood, and inverse linear correlation was established between the content of PCB in the blood of nestlings and the success of breeding of the pied flycatcher in Perm. An epidemiological analysis revealed a high incidence of cancer among the human population of the Industrialniy and Leninskiy districts (371.7 and 376.85 cases per 100,000 population, mean for the 2003-2018, respectively), which exceeded the figure for the whole of Perm (350.77 cases per 100,000 population, mean for the 2003-2018). The incidence rate of congenital malformations in Perm for the study period was 48.51 per 1000 human births. However, a decrease in the concentration of PCBs in soil and biota over a 15-year period (2005-2019) to the less than the detection limit did not lead to a decrease in the incidence of these diseases. Probably, PCB contamination was not the main cause of oncological diseases and congenital malformations in the population of the study area.

Congener-specific composition of polychlorinated biphenyls (PCBs) in soil-air partitioning and the associated health risks

The recent changes in the compositions of polychlorinated biphenyls (PCBs) after their restriction for 40 years may have various effects on human health. In order to characterize the congener-specific compositions of PCBs in the soil-air process and assess the associated human health risks, soil and air samples were simultaneously collected in winter and summer at two different functional locations. Homologue patterns suggest that long-range atmospheric transport might be the major source of soil and air residues of PCBs. The net deposition from air to soil was overwhelming for most PCB congeners. Variations in the occurrence and the homologue patterns of PCBs between the soil and air interface depended on chemical volatility, soil organic matter (OM) content, ambient temperature, topographical condition and atmospheric transport. Dioxin-like PCBs accounted for 11.0–70.3% and 2.31–54.8% of total PCB residues in soil and air, respectively. Non-carcinogenic and carcinogenic risks associated with exposure to soil and air PCBs were also estimated. Different PCB congeners showed different health effects, with the highest contribution from PCB-26. Additionally, the non-carcinogenic risk levels of PCBs were enhanced, while the carcinogenic risk levels decreased during the soil-air exchange process of PCBs with time. Our results highlight the soil-air interaction of PCBs in predicting their potential human exposure health risks.

Persistent Halogenated Organic Pollutants in Surface Water in a Megacity: Distribution Characteristics and Ecological Risks in Wuhan, China.

Surface water pollution in megacities is strongly linked to human and environmental health, and surface water quality has deteriorated sharply recently because of increasing persistent halogenated organic pollutant (HOP) concentrations. In the present study, we collected 112 water samples from 14 lakes and 11 drinking water sources in Wuhan, China, and analyzed them for two typical groups of HOPs: polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The mean values of the ΣPCB concentrations were 4.34 and 10.05ng L-1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53ng L-1 in winter and summer, respectively. The PCB and PBDE concentrations at most sites in summer were significantly higher than those in winter, probably because of heavy stormwater runoff in summer. The degree of urbanization predicted from the population density was positively correlated with ΣPCB concentrations in the drinking water sources in summer. PBDE and PCB composition analysis suggested the major sources were penta-BDE and Aroclor mixtures. Risk assessments showed the PBDEs in water from the Zhuankou site exceeded the threshold set by the European Union, which could result in adverse effects on aquatic organisms. Negligible noncarcinogenic risks were found for PCBs and PBDEs in the surface water with regard to drinking and bathing. However, the carcinogenic risks of PCBs for bathing in surface water were higher than the safe level of 1.00 × 10-6, implying that the surface water in Wuhan is not safe for bathing.

Occurrence, distribution and ecological risk of trace metals and organic pollutants in surface sediments from a Southeastern European river (Someşu Mic River, Romania)

The increasing contamination of fresh water resources by trace metals and persistent organic pollutants is a major environmental concern. In the present study, we investigated, for the first time, the distribution, sources and ecological risk of trace metals and organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in surface sediments from a Southeastern European river (Someşu Mic River, Romania). Concentrations of Cd, Cr, Cu, Pb, Ni and Zn ranged from 0.04 to 0.4, 9.4 to 43.15, 7.2 to 65.6, 12.3 to 131.4, 14.7 to 47.7 and 42.1 to 236.8 mg kg−1 dw, respectively. Concentrations of total PAHs, PCBs and OCPs ranged from 24.8 to 575.6, 2.7 to 252.7 and 2.1 to 44.3 ng g−1 dw, respectively. Some sediment parameters, i.e., pH, total organic carbon (TOC) and total organic matter (OM) contents, played a significant role in the spatial distribution of contaminants. A combined analysis based on diagnostic ratios and multivariate analyses revealed PAHs originating mainly from pyrolytic sources. PCB compositions showed distinct contamination signatures for tri- to tetra-chlorinated PCBs, characteristic of contamination by Aroclor-1016 and -1254 technical mixtures. The dominant OCP congeners were α-HCH and p,p′-DDD, reflecting past use of technical HCHs and DDTs in agricultural practices. Metal source and pollution status was assessed using geoaccumulation index and enrichment factor, which indicate widespread pollution by Pb, Cd, Zn, Ni and Cu. The use of Sediments Quality Guidelines (SQGs), mean effect range-median quotient (m-ERM-Q) and toxic equivalent factor (TEF) indicated that the highest ecological risks occurred for PCBs and DDTs. This work presents not only initial baseline information on the extent of organic and inorganic contaminations in a river of ecological and economical interest, but also provides a diagnostic ratio/statistical combined approach that can be used to evaluate sediment quality in similar environments.

Effects of Ferric Oxyhydroxide on Anaerobic Microbial Dechlorination of Polychlorinated Biphenyls in Hudson and Grasse River Sediment Microcosms: Dechlorination Extent, Preferences, Ortho Removal, and Its Enhancement.

Microbial reductive dechlorination of polychlorinated biphenyls (PCBs) has been observed in many PCB-impacted sediments. However, this biodegradation is relatively site-specific and can be affected by PCB compositions and sediment geochemical conditions. To better understand the influence of a common competing electron acceptor, ferric oxyhydroxide (FeOOH), on dechlorination, two sediments (Hudson River and Grasse River sediments), and two PCB mixtures (PCB 5/12, 64/71, 105/114, and 149/153/170 in Mixture 1 and PCB 5/12, 64/71, 82/97/99, 144/170 in Mixture 2) were used for this microcosm study. The addition of 40 mmole/kg FeOOH completely inhibited PCB dechlorination in the Hudson sediment, but only moderately inhibited PCB dechlorination in the Grasse sediment with a 3-week longer lag time. The inhibitory effect in the Grasse sediment was mainly due to the loss of unflanked para dechlorination activity. Fe(II) analysis showed that dechlorination started prior to the consumption of Fe(III), which indicates PCB reduction and Fe(III) reduction were able to take place concurrently. Dehalococcoides 16S rRNA genes increased with the commencement of dechlorination in the Grasse sediment, but not in the completely inhibited Hudson sediment. Rare ortho dechlorination pathways were identified in FeOOH-amended Grasse sediment microcosms, dominated by transformations of PCB 25(24-3-CB) to PCB 13(3-4-CB) and PCB 28(24-4-CB) to PCB 15(4-4-CB). The addition of carbon sources (acetate or a fatty acid mixture with acetate, propionate, and butyrate) after 27 weeks of incubation reinitiated dechlorination in FeOOH-amended Hudson sediment microcosms. Also, the addition of carbon sources greatly enhanced ortho dechlorination in FeOOH-amended Grasse microcosms, indicating the utilization of acetate and/or the fatty acid mixture for ortho dechlorination-related microorganisms. A dechlorination pathway analysis approach revealed that para-flanked meta dechlorination was primarily preferred followed by ortho-/double-flanked meta dechlorination and single-/double-flanked para dechlorination in the Grasse sediment.

Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

Polychlorinated biphenyls (PCBs) can be used as chemical sentinels for the assessment of anthropogenic influences on Arctic environmental change. We present an overview of studies on PCBs in the Arctic and combine these with the findings from ArcRisk—a major European Union-funded project aimed at examining the effects of climate change on the transport of contaminants to and their behaviour of in the Arctic—to provide a case study on the behaviour and impact of PCBs over time in the Arctic. PCBs in the Arctic have shown declining trends in the environment over the last few decades. Atmospheric long-range transport from secondary and primary sources is the major input of PCBs to the Arctic region. Modelling of the atmospheric PCB composition and behaviour showed some increases in environmental concentrations in a warmer Arctic, but the general decline in PCB levels is still the most prominent feature. ‘Within-Arctic’ processing of PCBs will be affected by climate change-related processes such as changing wet deposition. These in turn will influence biological exposure and uptake of PCBs. The pan-Arctic rivers draining large Arctic/sub-Arctic catchments provide a significant source of PCBs to the Arctic Ocean, although changes in hydrology/sediment transport combined with a changing marine environment remain areas of uncertainty with regard to PCB fate. Indirect effects of climate change on human exposure, such as a changing diet will influence and possibly reduce PCB exposure for indigenous peoples. Body burdens of PCBs have declined since the 1980s and are predicted to decline further.

Temporal trends in dioxin-like polychlorinated biphenyl concentrations in serum from the general population of Shandong Province, China: A longitudinal study from 2011 to 2017

Temporal changes in the concentrations of dioxin-like (DL) polychlorinated biphenyls (PCBs) in environmental and biological matrices in China are not well understood. We determined the DL-PCB concentrations in pooled serum samples from the general population of Weifang City, Shandong Province, China in 2011 (n = 305) and 2017 (n = 495). The total DL-PCB concentration was 3.48 ± 1.31 ng/g lipid (mean ± standard deviation) in 2011 and 2.82 ± 1.73 ng/g lipid (19% lower) in 2017, but the difference was not statistically significant (p = 0.347). The DL-PCB concentrations and toxic equivalent concentrations were much lower in the serum from Weifang residents than have been found in serum from the inhabitants of other parts of the world. The concentrations of most of the DL-PCB congeners followed different downward temporal trends, but the PCB-118 concentration was higher in 2017 than in 2011. The temporal changes in the PCB concentrations and compositions in the samples from the general population of Weifang indicated that there may a new source of unintentionally produced PCBs in Weifang.