Residues of Polychlorinated Biphenyls (PCBs) in Sediment from CauBay River and Their Impacts on Agricultural Soil, Human Health Risk in KieuKy Area, Vietnam

Exposure sources of polychlorinated biphenyls (PCBs) and health risk assessment: a systematic review in Iran

This systematic review aims to identify the sources of exposure to polychlorinated biphenyls (PCBs), portioning, and human health risk assessment in Iran. The literature was searched in the international databases of Web of Science, PubMed, Scopus, Google Scholar, and the national databases of SID and MagIran up to November 14, 2020. Among all 153 articles, 21 eligible papers were identified. Among them, only one article was related to drinking water, the rest was related to food and soil, and no article was found on ambient air. The corrected portion of each exposure source was determined to be 90% for food, 9% for water, and 1% for air. The total hazard quotient (HQ) was determined to be within an unsafe range, and the total excess lifetime cancer risk (ELCR) was determined to be at a high risk of oral carcinogenesis. It is suggested that a comprehensive study be conducted in a specific period for all sources of exposure in all counties of Iran. Moreover, it is recommended that the policymakers set national standards for this pollutant in near future in some sources of exposure (e.g., drinking water) which have no standards in Iran.

Seasonal distributions and risk assessment of polychlorinated biphenyls (PCBs) in the surficial sediments from the Turag River, Dhaka, Bangladesh

Polychlorinated biphenyls (PCBs) were determined in sediment samples collected from the Turag River, Dhaka city, Bangladesh. This river provides critical ecological services to agriculture, industry, and transportation. However, it is one of the most polluted rivers surrounding the capital city. This study analyzed six PCB congeners (PCB 10, PCB 28, PCB 52, PCB 138, PCB 153, and PCB 180) by GC-ECD at 9 sampling sites in two different seasons. The total concentrations of PCBs in studied samples varied from 344 to 0.217 ng/g dw and 10.6 to 1.68 ng/g dw in Monsoon-season and Dry-season, respectively. The paramount contributor-congener to the total PCBs was PCB 180, and it was found at all the study sites. The ecological risk assessment indicated a high potential risk in the Monsoon-season ([Formula: see text]= 277) and low potential risk in the Dry-season ([Formula: see text]= 25.7). Sediment quality guideline quotients (SQGQs) showed that PCBs in the Monsoon-season would cause "no" or "moderate" biological effects on organisms at every site except site-5 (S5) (high biological effects), while no adverse ecotoxicological effect was observed in the Dry-season. Considering both probable effect level (PEL) and threshold effect level (TEL), the new sediment quality guideline quotient (NSQGQ) showed that in the Dry-season PCB contamination would cause "moderate" biological effects. At the same time, in the Monsoon-season, the findings remained consistent with the findings of SQGQ. This study looked at the PCB contamination scenario in the Turag River sediments for the first time and allowed for a comparison with other rivers worldwide.

Occurrence and spatial characteristics of polychlorinated biphenyls (PCBs) in sediments from rivers in the western Niger delta of Nigeria impacted by urban and industrial activities

The characteristic concentrations of 28 PCB congeners, their spatial distributions, sources, and associated risks to the ecosystem were investigated in sediments of some rivers around a glass industry and power generating plant in the Niger Delta of Nigeria. Gas chromatography-mass spectrometry (GC-MS) was applied for the identification and quantification of PCBs in sediments from these rivers. The Ʃ28 PCB concentrations (dry weight) in sediments ranged from 1520 to 3540 ng g^-1 for the Afiesere River, 976-5670 ng g^-1 for the Edor River, and from 1440 to 6340 ng g^-1 for the Okpare River. The homologue distribution patterns in sediments from these rivers indicated that low-chlorinated (2 Cl to 5 Cl) PCBs were more dominant than high-chlorinated (6 Cl to 10 Cl) PCBs with tri-, penta- and deca-PCBs as the top homologues. The PCB source analyses suggested that the PCB contamination of these river sediments could have originated from Aroclor mixtures, paints, pigments and other inadvertent sources. The risk assessment indicated a high risk to the ecosystem.

Comprehensive determination of polychlorinated biphenyls and brominated flame retardants in surface sediment samples from Hanoi urban area, Vietnam: Contamination status, accumulation profiles, and potential ecological risks

Comprehensive and updated information about polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) in surface sediments from Hanoi, the capital city of Vietnam, is rather scarce. In this study, concentrations and profiles of 209 PCBs, 41 polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), hexabromocyclododecane (HBCD), pentabromoethylbenzene (PBEB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and decabromodiphenyl ethane (DBDPE) were determined in sediment samples collected from the Red River and some inner-city rivers of Hanoi. Concentrations (ng/g dry weight, median and range) of pollutants decreased in the order: DBDPE (28; not detected ND - 59) ≈ PCBs (27; 1.7-50) > PBDEs (23; 0.20-61) > HBCD (1.2; ND - 5.2) > BTBPE (0.46; ND - 3.6) > BB-153 (0.004; ND - 0.014) > PBEB (ND). Pollutant levels in the inner-city river sediments were about one to two orders of magnitude higher than those measured in the Red River main stream sediments. Tri-to hexa-CBs are major homologs but detailed profiles vary between individual samples, reflecting source and/or seasonal variations. CB-11 and CB-209 were found at higher proportions in sediments than in technical PCB mixtures, suggesting their novel sources from pigments. Deca-BDE and DBDPE are the most predominant BFRs with an increasing trend predicted for DBDPE. A preliminary ecological risk assessment was conducted for these pollutants in sediments. Total PCBs and deca-BDE in a few inner-city river sediments may exhibit adverse effects on benthic organisms, but no serious risk was estimated in general.

Endocrine disrupting compounds in sediment from KimNguu river, Northern area of Vietnam: a comprehensive assessment of seasonal variation, accumulation pattern and ecological risk

This research presents the assessment of seasonal variation, accumulation pattern and ecological risk of selected endocrine disrupting compounds (S-EDCs) in sediment samples covering six sites in KimNguu river, Hanoi, Northern area of Vietnam. Selected EDCs compose polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Sediment sampling was carried out in dry season (April) and wet season (October) in 2018. Results pointed out a significant contamination with ∑₆PCBs, ∑₁₆PAHs and ∑₇PBDE concentrations ranging from 4.73 to 36.34 ng g^-1 dw, from 3.57 to 84.39 ng g^-1 dw and from 4.49 to 12.49 ng g^-1 dw, respectively. Composition analyses indicated the predominance of PCB 138, PCB 153, M-PAHs (Middle molecular weight PAHs: BaA, Chr, Pyr, Flt), BDE-47, BDE-99 and BDE-209. The values of TEQ_DL-PCBs, TEQ_∑8PAHs and TEQ_∑16PAHs range from 4.6 to 10.4 ng kg^-1 dw, from 0.28 to 1.28 ng g^-1 dw and from 0.29 to 1.38 ng g^-1 dw, respectively. Ecological risks of S-EDCs range from very low to medium levels in the sediment of KimNguu river.

Endocrine Disrupting Compounds (EDCs) in Surface Waters of the KimNguu River, Vietnam

This research presents the assessment of contamination status, congener profiles and ecological risk of selected endocrine disrupting compounds (S-EDCs) in surface water from KimNguu River, Hanoi. Selected EDCs compose polychlorinated biphenyls (PCBs), phthalate esters (PAEs) and polybrominated diphenyl ethers (PBDEs). Water sampling and chemical analyses were carried out in collected water samples in dry season (April) and wet season (October) in 2018. Results pointed out a significant contamination with ∑₆PCBs, ∑₆PAEs and ∑₇PBDE concentrations ranging from 1.89 to 8.93 ng/L, from 2.78 to 412.27 ng/L and from 1.92 to 7.08 ng/L, respectively. Composition analyses indicated the predominance of PCB52, PCB118, DEP, DEHP, DBP, BDE-47 and BDE-99. Ecological risks of S-EDCs range from very low to medium levels in the surface water of KimNguu River.

Characterization, source identification and risk associated with polyaromatic and chlorinated organic contaminants (PAHs, PCBs, PCBzs and OCPs) in the surface sediments of Hooghly estuary, India

The spatial distribution, source identification and ecotoxicological impact of a group of persistent organic pollutants (POPs: dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexanes (HCHs), polychlorobiphenyls (PCBs), polychlorobenzenes (PCBzs)), and polyaromatic hydrocarbons (PAHs) were investigated in surface sediment samples (0-5 cm, <63 μm grain size) along the ecologically stressed Hooghly River estuary, East India. The results demonstrated a wide range of concentrations (ng/g dry weight) with the following decreasing order: ∑₁₆PAHs (3.3-630) > ∑₆DDTs (0.14-18.6) > ∑₇PCBs (0.28-7.7) > ∑₂PCBzs (0.01-1.3) > ∑₅HCH (0.10-0.6), with a dominance of p,p'-DDT and higher molecular weight PAHs. Selected diagnostic ratios indicated a mixture of both pyrolytic and petrogenic sources of PAHs, inputs of weathered DDT and their degradation in oxidizing environment, and a predominance of industrial input over the agricultural wastes. The cumulative impact of the pollutants (effective range medium quotient (ERMq): 0.01-0.16) reflected minimal to low ecotoxicological risk, with highest probability of toxic effects towards surrounding biota at Barrackpore (21%). ∑₆DDTs exceeded the effect range low value resulting occasional adverse impact to the sediment dwelling organisms. Among the PAHs, the 4-ringed compounds accounted for 68% of the PAHs. Further, carcinogenic PAHs (BaA, Chry, BbF, BkF, BaP, DahP, Inp) possessed highest cancer risk (CR = 2.09 × 10^-3) to the local population when exposed to the sediments from the studied area and ingestion was found to be the primary process of contamination. The study strongly recommends a systematic monitoring of POPs and PAHs, being the Hooghly River water used by local people for their livelihood.

Characterization of 209 polychlorinated biphenyls in street dust from northern Vietnam: Contamination status, potential sources, and risk assessment

A full congener-specific determination of polychlorinated biphenyls (PCBs) was conducted for street dusts in some areas in northern Vietnam. Total 209 PCB concentrations (median and range) of 14 (2.2-120), 11 (6.6-32), and 0.25 (0.10-0.97) ng g^-1 were measured in the street dusts from an industrial park, an urban area, and a rural commune, respectively, suggesting environmental loads of PCBs related to industrialization and urbanization in northern Vietnam. PCB patterns of street dusts from the industrial park were dominated by lightly chlorinated homologs (tri- and tetra-CBs), while more highly chlorinated homologs (penta- and hexa-CBs) were the major contributors to total PCBs in the urban samples, indicating different emission sources. Linear correlations of log-transformed sum of 7 indicator congeners with total PCBs and sum of dioxin-like PCBs were observed. PCB-11, an inadvertently produced congener of pigment manufacturing processes, was detected in all the samples with more elevated proportions in the urban and rural areas than industrial park. Our results have revealed complex emission sources of PCBs in the study areas, including both historical (e.g., the past usage of imported PCB-containing oils and old electric equipment) and current sources such as releases from industrial activities and increasing use of new consumer products. Occupationally exposed persons (e.g., street sweepers, street vendors, and traffic policemen) and children in the urban and industrial areas were estimated to receive much higher doses of dust-bound PCBs than general population, suggesting the need for appropriate protection conditions.

Occurrence, ecological risk assessment, and spatio-temporal variation of polychlorinated biphenyls (PCBs) in water and sediments along River Ravi and its northern tributaries, Pakistan

Ecological risk assessment, spatio-temporal variation, and source apportionment of polychlorinated biphenyls (PCBs) were studied in surface sediments and water from River Ravi and its three northern tributaries (Nullah Deg, Nullah Basantar, and Nullah Bein) in Pakistan. In total, 35 PCB congeners were analyzed along 27 sampling stations in pre-monsoon and post-monsoon seasons. The ∑₃₅PCB concentration ranged from 1.06 to 95.76 ng/g (dw) in sediments and 1.94 to 11.66 ng/L in water samples, with hexa-CBs and tetra-CBs as most dominant homologs in sediments and water matrixes, respectively. The ∑₈DL-PCB levels were 0.33-22.13 ng/g (dw) and 0.16-1.95 ng/L in sediments and water samples, respectively. The WHO-toxic equivalent values were ranged from 1.18 × 10^-6 to 0.012 ng/L and 1.8 × 10^-6 to 0.031 ng/g in water and sediments matrixes, respectively. The ecological risk assessment indicates considerable potential ecological risk during pre-monsoon season ([Formula: see text] = 95.17) and moderate potential ecological risk during post-monsoon season ([Formula: see text] = 49.11). The industrial and urban releases were recognized as key ongoing sources for high PCB levels in environment. Therefore, we recommend more freshwater ecological studies to be conducted in the study area and firm regulatory initiatives are required to be taken in debt to the Stockholm Convention, 2001 to cop up with PCB contamination on emergency basis.

Human Health Risks Assessment Associated with Polychlorinated Biphenyls (PCBs) in Soil from Different Contaminated Areas of Mexico

Recent studies have documented environmental contamination by PCBs in soil from different areas in Mexico (industrial, mining, and urban sites). However, the real significance of that soil contamination has not been established. Therefore, the aim of this study was to perform a human health risk assessment (Monte Carlos simulation) to evaluate the probable toxic effects of soils contaminated with PCBs on children in four sites in Mexico. A high non-carcinogenic risk (total nHQ = 1.1E+01; if nHQ ≥1, hazardous health effects cannot be ruled out) was found in Alpuyeca, Morelos, Mexico. Moreover, the total CR (cancer risk) found in Alpuyeca, Morelos is of concern (total CR = 5.1E-03), being that a cut-point of 1.0E-06 has been suggested as a safe level for cancer risk. Taking into consideration the data shown in this research, we conclude that a strategy to protect human health is necessary for the assessed sites.

Enantio-alteration of gene transcription associated with bioconcentration in adult zebrafish (Danio rerio) exposed to chiral PCB149

Enantioselective enrichment of chiral PCB149 (2,2’,3,4’,5’,6-hexachlorobiphenyl) was analysed in adult zebrafish (Danio rerio) exposed to the racemate, (−)-PCB149, and (+)-PCB149. Greater enrichment of (−)-PCB149 compared to (+) PCB149 was observed following 0.5 ng/L exposure; however, as the exposure time and concentration increased, racemic enrichment was observed in adult fish exposed to the racemate. No biotransformation between the two isomers was observed in fish exposed to single enantiomers. When zebrafish were exposed to different forms of chiral PCB149, enantioselective expression of genes associated with polychlorinated biphenyls (PCBs) was observed in brain and liver tissues and enantioselective correlations between bioconcentration and target gene expression levels were observed in brain and liver tissues. The strong positive correlations between expression levels of target genes (alox5a and alox12) and PCB149 bioconcentration suggest that prolonged exposure to the racemate of chiral PCB149 may result in inflammation-associated diseases. Prolonged exposure to (−)-PCB149 may also affect metabolic pathways such as dehydrogenation and methylation in the brain tissues of adult zebrafish. Hepatic expression levels of genes related to the antioxidant system were significantly negatively correlated with bioconcentration following exposure to (+)-PCB149.