Assessment of polychlorinated biphenyls (PCBs) in the Himalayan Riverine Network of Azad Jammu and Kashmir

Effects of temperature, relative humidity and soil organic carbon content on soil-air partitioning coefficients of volatile PFAS

Soil-air partitioning coefficient (KSA) values are often used to assess the environmental fate of organic contaminants in soil. Till now, sufficient KSA values have not yet been measured for many compounds of interest, including some emerging pollutants such as volatile PFAS. Moreover, the effects of environmental factors such as temperature, relative humidity and soil organic carbon content on KSA of volatile PFAS are also unclear. In this study, the KSA values of target volatile PFAS were measured under various temperature (20-40 °C), relative humidity (30-100 %) and soil organic carbon content (2.1 %-8.0 %) using a modified solid-phase fugacity meter. The results showed that higher temperatures, higher relative humidity and lower organic carbon content in soil may accelerate the diffusion of target volatile PFAS. Furthermore, the KSA measurements were used to derive a multiple linear regression model to depict the relationship between logKSA and temperature, relative humidity, soil organic carbon content and PFAS-specific logKOA. When compared with the predictions obtained from semi-empirical model, we argued that the multiple linear regression model is more robust and easier to implement for target volatile PFAS or other emerging volatile PFAS than the semi-empirical approach to help depict the diffusion process at target volatile PFAS contaminated sites.

Spatial distributions and source identification of PCDD/Fs and PCBs in soils and pine needles in the multi-industrial city of Ulsan, South Korea

The spatial distribution and contamination patterns of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in soil and pine needles from the multi-industrial city of Ulsan, South Korea were assessed. The mean concentrations of Σ17 PCDD/Fs, Σ12 dl-PCBs, and Σ7 I-PCBs were 78 pg/g dw, 90 pg/g dw, and 453 pg/g dw in the soil and 6 pg/g ww, 31 pg/g ww, and 166 pg/g ww in the pine needles, respectively. The mean concentrations of PCDD/Fs, dl-PCBs, and I-PCBs in the soil at industrial sites (138, 184, and 453 pg/g dw) were significantly higher than those at urban (47, 33, and 186 pg/g dw) and suburban sites (48, 49, and 234 pg/g dw). In the pine needles, although PCDD/F and PCB levels were higher at several industrial sites, mean concentrations at the industrial (6, 31, and 166 pg/g ww), urban (4, 29, and 143 pg/g ww), and suburban (4, 31, and 169 pg/g ww) sites were comparable, indicating that atmospheric transport plays a crucial role in spreading contamination throughout the study area. Higher chlorinated PCBs were predominant in the soils, while PCDFs and lower chlorinated PCBs were more common in the pine needles, reflecting the distinct physicochemical properties and interactions of these chemicals with each medium. Principal Component Analysis (PCA) revealed industrial combustion as the main source of PCDD/Fs and PCBs, with Aroclors identified as an additional source of PCBs. Suburban areas were influenced by both local sources and pollutants transported from urban and industrial areas. This study highlights that industrial activities and atmospheric transport significantly contribute to the widespread contamination of PCDD/Fs and PCBs in Ulsan.

Distribution, bioaccumulation, and health risk assessment of organochlorines across the riverine ecosystem of Punjab Province, Pakistan

This study was designed to assess the distribution of organochlorines (OCs) in fish species, their spatio-temporal variations, bioaccumulation potential, and associated human health risks via dietary intake. The levels of twenty-three organochlorine pesticides (OCPs) and thirty-five polychlorinated biphenyls (PCBs) were analyzed in six fish species collected from the riverine ecosystem of Punjab Province, Pakistan. The results indicated that the mean levels of Σ23OCPs were 74.1 ng/g ww and 184 ng/g ww, and for Σ35PCBs the levels were 38.8 ng/g ww and 74.8 ng/g ww in herbivorous and carnivorous fish species, respectively. The most abundant contaminants in all fish species were DDTs (65%) and HCHs (14%) among OCPs and heavier PCB congeners (62%) among PCBs. As for dioxin-like PCBs, the WHO toxic equivalency values (ng TEQ/g ww) were in the range of 0.21 (Cyprinus Carpio) to 2.38 (Rita Rita), exceeding the maximum allowable limit of 0.004 ng TEQ/g, ww by the European Commission. Spatio-temporal analysis indicated relatively higher OC levels in winter season with elevated concentrations in fish samples from industrial zone. The bioconcentration factor (L/kg) values ranged from 723 to 2773 for PCBs and 315 to 923 for OCPs in all fish species, with higher levels were reported in carnivorous species. The human health risk assessment at both 50th and 95th percentiles revealed the absence of any significant non-carcinogenic risk as calculated HR was less than 1. However, the critical carcinogenic risk was found to be associated for most of the contaminants, signifying the dietary exposure to OCPs and PCBs might pose the public health concern.

Concentration levels, spatial variations and exchanges of polychlorinated biphenyls (PCBs) in ambient air, surface water and sediment in Bursa, Türkiye

In this study, ambient air, surface water and sediment samples were simultaneously collected and analyzed for PCBs to investigate their levels, spatial variations and exchanges between these three compartments at different sampling sites for 12 months in Bursa, Türkiye. During the sampling period, a total of 41 PCB concentrations were determined in the ambient air, surface water (dissolved and particle phase) and sediment. Thus, 945.9 ± 491.6 pg/m³ (average ± STD), 53.8 ± 54.7 ng/L, 92.8 ± 59.3 ng/L and 71.4 ± 38.7 ng/g, respectively. The highest concentrations of PCBs in the ambient air and in water particulate phase were measured at the industrial/agricultural sampling site (1308.6 ± 252.1 pg/m³ and 168.7 ± 21.2 ng/L, respectively), ∼ 4-10 times higher than background sites; while the highest concentrations in the sediment and dissolved phase were measured at the urban/agricultural sampling sites (163.8 ± 27.0 ng/L and 145.7 ± 15.3 ng/g, respectively), ∼ 5-20 times higher than background sites. PCB transitions between ambient air-surface water (f_A/f_W) and surface water-sediment (f_W/f_S) were investigated by fugacity ratio calculations. According to the fugacity ratios obtained, volatilization from the surface water to the ambient air was observed at all sampling sites (98.7 % of f_A/f_W ratios are <1.0). Additionally, it has been determined that there is a transport from the surface water to the sediment (100.0 % of f_W/f_S ratios are higher than 1.0). The flux values in ambient air-surface water and surface water-sediment environments ranged from -1.2 to 1770.6 pg/m²-day and from -225.9 to 0.001 pg/m²-day, respectively. The highest flux values were measured for PCBs with low chlorine content (Mono-, Di-Cl PCBs), while the lowest flux values were measured for the high chlorine content PCBs (Octa-, Nona- and Deca-Cl PCBs). As it was determined in this study that surface waters contaminated by PCBs have the potential to pollute both air and sediments, it will be important to take measures to protect surface waters.

Organochlorines in the riverine ecosystem of Punjab province, Pakistan: contamination status, seasonal variation, source apportionment, and ecological risk assessment

The aim of the present study was to determine the occurrence, spatio-temporal variations, source apportioning, and ecological risk assessment of selected PCBs and OCPs in surface water and sediments collected riverine environment of Punjab province, Pakistan. The concentration of ΣOCPs (water: 64-455 ng/L; sediments: 117-616 ng/g) and ΣPCBs (water: 2-132 ng/L; sediments: 3.27-200 ng/g) was found comparatively higher than the levels reported from other parts of the world. The higher concentrations of DDTs and HCHs were detected in both studied matrices, whereas among PCBs, CB-28, 49 and CB-37, 82 were dominant in water and sediments, respectively. The isomeric ratios including α-HCH/γ-HCH, (DDE + DDD) / DDTs, and α /β-endosulfan reflected the recent use of lindane, technical DDT, and endosulfan in the study area. The WHO-TEQ values of DL-PCBs ranged from 3.6 × 10^-6 to 0.115 ng/L and 8.7 × 10^-6 to 0.157 ng/g in surface water and sediments in both seasons, respectively. The spatial variation analysis revealed that the sites in the industrial and agricultural zones were highly contaminated. The OCPs and PCBs fluxes to downstream areas were estimated to be 12.4 tons/year and 1.9 tons/year, respectively. The significant ecological risks were estimated to be posed by OCPs and PCBs, as their levels in 67% and 62% of surface water and sediment samples were exceeding the threshold limits, highlighting effects to ecological integrities.

Spatial distribution and ecological risks of polychlorinated biphenyls in a river basin affected by traditional and emerging electronic waste recycling in South China

With development of e-waste related legislation in China, formal recycling activities are designated in some areas while informal ones are illegally transferred to emerging areas to avoid supervision. However, the resulting environmental impact and ecological risks are not clear. Here, we investigated the discharge of polychlorinated biphenyls (PCBs) to soil and aquatic environments by e-waste recycling activities in the Lian River Basin, China. The study area included a designated industrial park in the traditional e-waste recycling area (Guiyu, known as the world's largest e-waste center), several emerging informal recycling zones, and their surrounding areas and coastal area. A total of 27 PCBs were analyzed, and the highest concentration was found in an emerging site for soil (354 ng g^-1) and in a traditional site for sediment (1350 ng g^--1) respectively. The pollution levels were significantly higher in both the traditional and emerging recycling areas than in their respective upstream countryside areas (p = 0.0356 and 0.0179, respectively). Source analysis revealed that the traditional and emerging areas had similar PCB sources mainly associated with three PCB technical mixtures manufactured in Japan (KC600) and the USA (Aroclor 1260 and Aroclor 1262). The PCB pollution in their downstream areas including the coastal area was evidently affected by the formal and informal recycling activities through river runoff. The ecological risk assessments showed that PCBs in soils and sediments in the Lian River Basin could cause adverse ecotoxicological consequences to humans and aquatic organisms.

Legacy and new chlorinated persistent organic pollutants in the rivers of south India: Occurrences, sources, variations before and after the outbreak of the COVID-19 pandemic

During pre-pandemic time, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the surface water of Periyar River (PR) and Bharathappuzha River (BR) in Ernakulam and Malappuram districts of Kerala, respectively and Adyar River (AR) and Cooum River (CR) in Chennai district of Tamil Nadu. After the outbreak of COVID-19 pandemic, variation in OCPs and PCBs were evaluated for AR and CR. Dominance of β-HCH and γ-HCH in south Indian rivers indicate historical use of technical HCH and ongoing use of Lindane, respectively. In > 90 % sites, p,p'-DDT/ p,p'-DDE ratio was < 1, indicating past DDT usage. However during the outbreak of the COVID-19 pandemic, elevated p,p'-DDT in AR and CR reflects localized use of DDT possibly for vector control. Similarly, during the first wave of pandemic, over a 100-fold increase in PCB-52 in these rivers of Chennai mostly via surface run-off and atmospheric deposition can be reasoned with open burning of dumped waste including added waste plastic in the solid waste stream. On contrary, a significant (p < 0.05) decline of dioxin-like PCBs level, suggests lesser combustion related activities by the formal and informal industrial sectors after the lockdown phase in Tamil Nadu. Eco-toxicological risk assessment indicated a higher risk for edible fish in PR due to endosulfan.

North-south geographic heterogeneity and control strategies for polycyclic aromatic hydrocarbons (PAHs) in Chinese lake sediments illustrated by forward and backward source apportionments

As universal and supervirulent pollutants, understanding the potential sources of polycyclic aromatic hydrocarbons (PAHs) in lakes is critical for formulating pollutant control policies that will ensure the ecological safety of aquatic environments. Geographic heterogeneity of PAHs in lake sediments from China nationwide was investigated to indicate north-south dissimilarities in PAH levels and sources and propose specific PAH control strategies. Geographic PAH patterns showed that higher concentrations were found in the south compared to the north due to higher energy consumption and more intense industrial activities. Furthermore, the primary contributors in the south were high molecular weight (HMW) PAHs, whereas low molecular weight (LMW) PAHs were dominant in the north. The results of forward source apportionment based on the PAH emission method (EM) were consistent with the backward method using the positive matrix factorization (PMF) model, which verified the feasibility of the combined methods. Petroleum from transport was the dominant PAH source in the south, and purifying gasoline and diesel, promoting new energy vehicles and direct injection engines might effectively reduce PAH emission. Domestic coal was the main PAH source in the north, thereby adding active substance in coal and using cleaner energy could reduce PAH release.

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.

Polychlorinated biphenyls in indoor dust from urban dwellings of Lahore, Pakistan: Congener profile, toxicity equivalency, and human health implications

This study is the pioneer assessment of the PCBs in indoor dust particles (from air conditioners) of an urbanized megacity from South Asian. The ∑₃₅ PCB concentration ranged from 0.27 to 152.9 ng/g (mean: 24.84 ± 22.10 ng/g). The tri- and tetra-PCBs were dominant homologues, contributing 57.36% of the total PCB concentrations. The mean levels of Σ₈ -dioxin-like (DL), Σ₆ -indicator PCBs and WHO₂₀₀₅ -TEQ for DL-PCBs were 2.22 ± 2.55 ng/g, 9.49 ± 8.04 ng/g and 4.77 ± 4.89 pg/g, respectively. The multiple linear regression indicated a significant correlation of dusting frequency (p = 1.06 × 10-04) and age of the house (p = 1.02 × 10-06) with PCB concentrations in indoor environment. The spatial variation of PCB profile revealed relatively higher concentrations from sites near to illegal waste burning spots, electrical locomotive workshops, and grid stations. Human health risk assessment of PCBs for adults and toddlers through all three exposure routes (ie, inhalation, ingestion, and dermal contact) demonstrated that toddlers were vulnerable to high cancer risk (4.32 × 10^-04 ), while adults were susceptible from low to moderate levels of risk (3.16 × 10^-05 ). Therefore, comprehensive investigations for PCBs in the indoor settings, focusing particularly on the sensitive populations with relationship to the electronic devices, transformers, and illegal waste burning sites, are recommended.

Persistent organic pollutants (POPs) in fish species from different lakes of the lesser Himalayan region (LHR), Pakistan: The influence of proximal sources in distribution of POPs

Fish dwelling in remote mountain water systems are sensitive to long term exposure of POPs and can be used as an important bioindicator of POPs pollution in fragile mountain ecosystems. Current study aimed to investigate the concentrations and patterns of organic pollutants in fish tissues from different lakes of the Lesser Himalayan Region (LHR). OCPs, PCBs, PBDEs were analyzed in four common edible fish species of the LHR: Oncorhynchus mykiss, Labeo rohita, Hypophthalmichthys molitrix and Orechromis aureus. The fish were collected from lakes with different types of catchment areas (glacial, non-glacial mountain region and urban region) and extent of anthropogenic influence. The levels OCPs, PCBs and PBDEs analyzed in the selected fish species were in range of 0.21-587, 6.4-138 and 1.2-14 ng g^-1 lw, respectively. The ∑DDTs, higher chlorinated PCBs, tetra- and penta-BDEs were more prevalent in urban and remote lakes whereas pp'-DDE, lower chlorinated PCBs and BDE-47 and -99 were predominant in fish species from glacial lakes. ∑DDTs, ∑PCBs and ∑PBDEs showed statistically significant differences (p < 0.05) among species, trophic guilds (carnivore, herbivore and omnivore) and feeding regimes (surface, bottom and column feeder) and ∑HCH showed a significant difference only among trophic guilds. The stable isotope values of δ ¹⁵N and δ¹³C differed significantly among species for ∑HCH, ∑PCBs, ∑PBDEs (p < 0.05) and ∑DDT (p < 0.01). The range of δ¹³C values (-34 to -19‰) indicated the importance of littoral and pelagic sources of dietary carbon. Trophic position and dietary proxies were identified as important variables for explaining the variability of the studied compounds. Kohonen self-organizing maps (SOM) showed that in addition to trophic position and other physiological characteristics of fish, that the type of lakes and proximal sources of POPs were the most important predictors for distribution of organic contaminants in fish samples from LHR.

Distribution and ECo-Toxicological Risk Assessment of Legacy Persistent Organic Pollutants in Surface Water of Talar, Babolrood and Haraz Rivers

In the outer Alborz Range in the Northern Province of Iran, the Haraz, Talar and Babolrood Rivers are the three largest rivers where most of the agricultural, aquacultural and industrial activities are found. Total indicator polychlorinated biphenyls (iPCBs) ranged ND–474, ND–273 and ND–559 ng/L in Haraz, Talar and Babolrood Rivers, respectively. Significantly lower (p < 0.05) concentrations of DDT, lindane and dieldrin were observed in the upstream stations than downstream stations of both Babolrood and Haraz Rivers. However, in Talar River, PCB residues in upstream was significantly higher (p < 0.05) than downstream. Furthermore, PCB-28 in Talar River and PCB-101 and PCB-153 in Bablrood and Haraz Rivers were high in water samples at all stations. A significant difference was observed among the stations. In October, November and December, there was negligible variations in total PCB concentration among the stations. Alarming levels of some of the legacy persistent organic pollutants (POPs) may pose adverse effects on the aquatic species dwelling in the Talar, Babolrood and Haraz Rivers of Iran.