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The global increase in electronic waste (e-waste) has led to a rise in informal recycling, emitting hazardous heavy metals (HMs) that threaten human health and ecosystems. This study presents the first comprehensive assessment of HM levels in dry deposition and soils at proximity of forty (40) informal e-waste recycling sites across Pakistan, between September 2020 to December 2021. Findings reveal that Zn (1410), Pb (410) and Mn (231) exhibited the higher mean deposition fluxes (μg/m2.day), derived from air samples, particularly in Karachi. Similarly, soils showed higher mean concentrations (μg/g dw) of Mn (477), Cu (514) and Pb (172) in Faisalabad, Lahore, and Karachi, respectively. HMs concentrations were found higher in winter or autumn and lower in summer. In addition, HM levels were significantly (p = 0.05) higher at recycling sites compared to background sites year-round, highlighting the e-waste recycling operations as the major source of their emissions. The I geo index indicated moderate to extremely contaminated levels of Cu, Pb, Cd, and Ni in Karachi, Lahore and Gujranwala. Ingestion was found as a leading human exposure route, followed by dermal and inhalation exposure, with Pb posing the greatest health risk. The Cumulative Incremental Lifetime Cancer Risk (ILCR) model suggested moderate to low cancer risks for workers. Strategic interventions recommend mitigating health and environmental risks, prioritizing human health and ecosystem integrity in Pakistan's e-waste management. [Display omitted] • Informal e-waste recycling in Pakistan emits Zn, Mn, Pb, harming health/ecosystems. • Heavy metal concentration in air and soil for Karachi were the highest and warrant further attention. • Heavy metals in air exhibited seasonality and peaked in autumn/winter. • High human exposure estimates for Pb highlight the need for improved e-waste management in Pakistan. [ABSTRACT FROM AUTHOR]

This study was conducted with the aim of assessing the levels and black carbon mediated sediment–water partitioning of organochlorine pesticides (OCPs) from the Indus River. ∑OCPs ranged between 52−285 ng L −1 and 5.6–29.2 ng g −1 in water and sediment samples respectively. However, the ranges of sedimentary fraction of total organic carbon ( f TOC ) and black carbon ( f BC ) were 0.82–2.26% and 0.04–0.5% respectively. Spatially, OCPs concentrations were higher at upstream sites as compared to downstream sites. Source diagnostic ratios indicated the technical usage of HCH (α - HCH/γ - HCH>4) and significant presence of DDT metabolites with fresh inputs into the Indus River as indicated by the ratios of (DDE+DDD)/∑DDTs (0.27–0.96). The partitioning of OCPs between the sediments and water can be explained by two carbon Freundlich adsorption model which included both organic carbon and black carbon pools as partitioning media. [ABSTRACT FROM AUTHOR]

This study reports the first investigation of polychlorinated naphthalenes (PCNs) in air and soil samples from ecologically important sites of the Indus River Basin, Pakistan. The concentrations of ∑ 39 -PCNs in air and soil were found in a range between 1–1588 pg m −3 and 0.02–23 ng g −1 while the mean TEQ values were calculated to be 5.4E −04 pg TEQ m −3 and 1.6E +01 pg TEQ g −1 , respectively. Spatially, air and soil PCN concentrations were found to be high at Rahim Yar Khan (agricultural region). Lower-medium chlorinated PCNs (sum of tri-, tetra- and penta-CNs) predominated in both air and soil, altogether constituting 87 and 86% of total PCNs in the two environmental matrices, respectively. According to the data, soil–air partitioning of PCNs was interpreted to be similarly controlled by the combined effect of black carbon and organic matter in the Indus River Basin, with no preferential implication of the recalcitrant organic form. [ABSTRACT FROM AUTHOR]

This review article focuses on the current situation of e-waste in Pakistan with the emphasis on defining the major e-waste recycling sites, current and future domestic generation of e-waste, hidden flows or import of e-waste and discusses various challenges for e-waste management. Needed policy interventions and possible measures to be taken at governmental level are discussed to avoid the increasing problem of e-waste in the country. Our findings highlight that there is still a general lack of reliable data, inventories and research studies addressing e-waste related issues in the context of environmental and human health in Pakistan. There is therefore a critical need to improve the current knowledge base, which should build upon the research experience from other countries which have experienced similar situations in the past. Further research into these issues in Pakistan is considered vital to help inform future policies/control strategies as already successfully implemented in other countries. [ABSTRACT FROM AUTHOR]

Abstract: An initial survey of the concentrations of polychlorinated biphenyl (PCB) compounds in air and soils across industrial and agricultural areas of Punjab Province, Pakistan, was conducted from January to March 2011. The total concentration of all PCBs (31 PCBs) ranged from 34 to 389pgm−3 in air and from 7 to 45ngg−1 dry weight in soils, where both ranges were similar to the average ranges in other areas of the world. PCBs were elevated across industrial regions near urban and industrial sources. Consistently low air concentrations of PCBs at the agricultural sites suggest that they are less widespread or uniformly distributed in the Pakistani atmosphere. The calculated air and soil fugacity fraction values indicated that soils are a potential secondary source of PCBs in agricultural areas, whereas they are in equilibrium or atmospheric deposition in industrial and urban areas. TEQ concentrations of dioxin-like PCBs for soil samples met the Canadian standard. However, local authorities should address the human health threats from urban and industrial soils in Punjab Province, Pakistan. [Copyright &y& Elsevier]

Feathers of two colonial water-birds species (Bubulcus ibis, Egretta garzetta) from four heronries in the Punjab province, Pakistan were analysed for 28 Polybrominated Diphenyl Ethers (PBDEs) congeners. Median concentrations of ∑PBDEs were 2.41 and 1.91 ng/g in little and cattle egrets. PBDE-47, -100, -138, -153 were abundant and detected in >70% of feather samples in both species. Species-specific differences based on dietary preferences indicated higher concentration of PBDE-47, -66, -75, -100, -153, -154, and -183 in fish eating little egret. BDE-47 and -100 were more frequent in little egrets and BDE-99 was more dominant in cattle egret which feed on terrestrial habitat. Higher ∑hexa- and hepta-BDEs congeners showed larger concentrations in feathers from heronries close to water bodies which receive urban and industrial effluents whereas lower-brominated congeners (BDE-47–BDE-100) dominated in rural/agricultural regions. Hazard quotients (HQs) indicated that measured ∑PBDEs pose no risk to egret population. [Copyright &y& Elsevier]

To date limited information's are available concerning unintentional productions, screening, profiling, and health risks of polychlorinated naphthalenes (PCNs) in ambient environment and occupational environment. Literature reveals that dust is a neglected environmental matrix never measured for PCNs. To our knowledge, this is the first study to investigate the concentrations and health risks of PCNs in indoor dust, air, and blood of major e-waste recycling hubs in Pakistan. Indoor air (n = 125), dust (n = 250), and serum (n = 250) samples were collected from five major e-waste hubs and their vicinity to measure 39 PCN congeners using GC-ECNI-MS. ∑ 39 PCN concentrations in indoor air, dust, and serum (worker > resident > children) samples ranged from 7.0 to 9583 pg/m3, from 0.25 to 697 ng/g, and from 0.15 to 401 pg/g lipid weight, respectively. Predominant PCN congeners in indoor air and dust were tri- and tetra-CNs, while tetra- and penta-CNs were dominant in human serum samples. The higher PCNs contribution was recorded at the recycling units, while the lower was observed at the shops of the major e-waste hubs. Higher contribution of combustion origin CNs in air, dust and human samples showed combustion sources at the major e-waste hubs, while Halowax and Aroclor based technical mixture showed minor contribution in these samples. Mean toxic equivalent (TEQ) concentrations of PCNs were 2.79E+00 pg-TEQ/m3, 1.60E−02 ng-TEQ/g, 8.11E−01 pg-TEQ/g, 7.14E−01 pg-TEQ/g, and 6.37E−01 pg-TEQ/g for indoor air, dust, and serum samples from workers, residents, and children, respectively. In our study, CNs- 66/67 and −73 in indoor air, dust, and human serum were the great contributors to total TEQ concentrations of PCNs. This first base line data directs government and agencies to implement rules, regulation to avoid negative health outcomes and suggests further awareness in regard of provision of proper knowledge to the target population. Image 1 • PCNs for first time in-sighted in dust & human serum from e-waste hubs in Pakistan. • Tri-to penta-CNs were dominant in indoor air, dust, and human serum samples. • Higher PCNs was recorded by Combustion based activities than technical mixture based CNs. • PCNs 66/67 and 73 congeners were great contributors to total TEQ concentrations. • Serum PCN concentrations in e-waste workers indicate potentials for health risks. Due to lack of data on production, screening, and profiling of PCNs, this is the first study to investigate concentrations of PCNs in indoor dust, air, and blood serum at the major e-waste recycling hubs in Pakistan where crude recycling methods were common and the potential health risks to human via its non-dietary pathways exposure would experience. This study results identified that Tri-to penta-CNs were dominant in the environmental samples and showed that higher PCNs contribution in the environmental samples was recorded by Combustion based activities as compared to technical mixture based CNs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Measurement of GEM emissions from urban atmosphere in Pakistan. • Open burning, and physical dismantling are common e-waste recycling practices. • E-waste sites from Karachi, Lahore, and Peshawar were found highly contaminated. • Lower seasonal variations indicating the stable emission sources throughout year. • Workers and public living close to these facilities are exposed to hazards of GEM. Detrimental effects of mercury (Hg) on ecosystems and human health have been well-documented. Whereas emissions of gaseous elemental mercury (GEM) from e-waste recycling have been reported in developed countries, much less is known about the situation in the Global South. Using a total of 132 passive air samplers, seasonally resolved concentrations of GEM in air were measured continuously at 32 informal e-waste recycling facilities and background location in Pakistan for a period of one year between September 2020 and December 2021. Annual average GEM concentrations at the studied locations ranged from 1.8 to 92 ng m−3. Among the studied cities, higher concentrations were measured in Karachi (mean ± s.d: 17 ± 22, range: 4.2–92 ng m−3), Lahore (16 ± 4.2, 8.2–22 ng m−3) and Peshawar (15 ± 17, 4.9–80 ng m−3), while lower levels were measured in Hyderabad (6.9 ± 6.2, 3.1–25 ng m−3), consistent with a higher rate of informal recycling activities in metropolitan areas. Seasonally, higher GEM levels occurred during autumn (15 ± 16: 3.3–92 ng m−3) and summer (13 ± 8.7: 1.8–80 ng m−3) than in winter (12 ± 8.4: 2.5–49 ng m−3) and spring (9.2 ± 7.3: 1.8–80 ng m−3), possibly reflecting enhanced volatilization at higher temperatures and/or varying magnitude of recycling operations in different seasons. Policies and strict regulations related to e-waste management should be developed and implemented urgently in the country. [ABSTRACT FROM AUTHOR]

Abstract The status of seven currently used pesticides were assessed under the influence of soil parameters in surface soils of cash crop growing areas of Pakistan. Chlorpyrifos occurred in highest mean concentration (1.18 mg kg−1). Selected pesticides exhibited higher affinity towards both organic carbon and black carbon fractions. The δ 13C stable carbon isotopic fraction of inorganic carbon was also used as a tracer and disclosed high retention of total organic carbon in Swat and Swabi sites. Statistical analysis revealed that carbon storage was primarily influenced by altitude and temperature. Soil clay mineral oxides of aluminum and iron positively correlated with organic carbon and selected pesticides (chlorpyrifos and cyprodinil). Soil to plant bio-concentration ratios predicted heightened uptake of azinfos and diazinon in major cash crop bio mass. Occupational risk via soil ingestion expressed no significant threat to the farmer community. Graphical abstract Image 1 Highlights • Current-use pesticides status in soil for six cash crop growing areas of Pakistan. • TOC/BC levels in cash crop growing areas and their influential role in sorption of current-use pesticides. • Inspecting organic carbon distribution pattern using stable carbon isotope as a tracer. • Effect of clay minerals and climatic factors on organic carbon retention and pesticide sorption. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides (OCPs) were investigated in passive air and soil samples from the catchment area of the Indus River, Pakistan. ∑ 15 OCPs ranged between 0.68 and 13.47 ng g −1 in soil and 375.1–1975 pg mˉ 3 in air. HCHs and DDTs were more prevalent in soil and air compartments. Composition profile indicated that β -HCH and p,p' -DDE were the dominant of all metabolites among HCHs and DDTs respectively. Moreover, f BC and f TOC were assessed and evaluated their potential role in the distribution status of OCPs. The f TOC and f BC ranged between 0.77 and 2.43 and 0.04–0.30% respectively in soil. Regression analysis showed the strong influence of f BC than f TOC on the distribution of OCPs in the Indus River catchment area soil. Equilibrium status was observed for β -HCH, δ -HCH, p,p' -DDD, o,p' -DDT, TC, HCB and Heptachlor with ff ranged between 0.3 and 0.59 while assessing the soil–air exchange of OCPs. [ABSTRACT FROM AUTHOR]

Levels of polychlorinated biphenyls (PCBs) were assessed in surface soils and passive air samples from the Indus River Basin, and the influential role of black carbon (BC) in the soil–air partitioning process was examined. ∑ 26 –PCBs ranged between 0.002–3.03 pg m −3 and 0.26–1.89 ng g −1 for passive air and soil samples, respectively. Lower chlorinated (tri- and tetra-) PCBs were abundant in both air (83.9%) and soil (92.1%) samples. Soil–air partitioning of PCBs was investigated through octanol–air partition coefficients ( K OA ) and black carbon–air partition coefficients ( K BC–A ). The results of the paired -t test revealed that both models showed statistically significant agreement between measured and predicted model values for the PCB congeners. Ratios of f BC K BC–A δ OCT / f OM K OA > 5 explicitly suggested the influential role of black carbon in the retention and soil–air partitioning of PCBs. Lower chlorinated PCBs were strongly adsorbed and retained by black carbon during soil–air partitioning because of their dominance at the sampling sites and planarity effect. [ABSTRACT FROM AUTHOR]

Extensive monitoring of organo-halogenated contaminants (OHCs) from surface soils of different land-use types from Pakistan was carried out during 2010. The concentrations (ng g − 1 ; dry weight) and profiles clearly indicated the dominance of ∑ DDT contaminants followed by the ∑ HCHs, ∑ 30 PCBs, chlordanes, and ∑ 10 PBDEs in descending order. Concerning the spatial patterns of occurrence, industrial soils exhibited relatively higher concentration of DDTs, heavy PCBs, and PBDEs (noticeably BDE-47 and -99 congeners), while the urban soils were characterized by high total PCBs (with relatively higher levels of light PCBs), following the agricultural soils. Compared to available criterion guidelines, the current results suggested that 10% of soil samples from industrial sites exhibited slightly higher levels (> 50 ng g − 1 ) of DDTs. The ∑ TEQ levels for mono-ortho DL-PCBs ranged from 0.7 to 5.65 (1.9) pg TEQ g − 1 dw in all the studied samples and PCB-118 contributed significantly towards the total calculated TEQs. The results of this study will contribute to the environmental management of OHCs contaminated areas of Pakistan. [ABSTRACT FROM AUTHOR]

Abstract: Polychlorinated naphthalenes (PCNs) are now under review by the Stockholm Convention as candidates for persistent organic pollutants (POPs) due to their persistence, toxicity, bioaccumulation, and long-range atmospheric transport. Data on PCN levels are sparse in South Asia. Atmospheric PCNs in India and Pakistan were monitored during the winter by polyurethane foam disk passive air samplers (PUF-PAS). The average concentrations were 29pg/m3 and 7.7pg/m3 in the Indian and Pakistani samples, respectively. Those concentration levels were relatively lower than the previously reported values in other Asian countries, but still considerably higher than in other sites in the world. Tri-CNs and tetra-CNs were the dominant homologues in the air, especially in India. Spatially, the PCNs were ubiquitous in the target areas, and local distribution was generally impacted by the proximity to potential sources. Major sources of PCNs in this study were the re-emission of Halowax and industrial thermal processes. Biomass burning influenced some sites in Pakistan. However, the enrichment of tri-CNs in Indian cities cannot be ascribed to either the signature of a specific source or the preferential volatilization and/or photodegradation in tropical areas. Despite this unclear issue in South Asia, the present study indicates that the potential health impact was generally comparable to that in non-urban sites worldwide. [Copyright &y& Elsevier]

Highlights: [•] First systematic data of PBDEs and DPs was reported from Pakistan. [•] BDE-209 was the most abundant PBDE congener in air, soils and sediments. [•] The fractions of anti-DP indicated the lack of DP production source in Pakistan. [Copyright &y& Elsevier]

Abstract: This study provides the first systematic data on the distribution of organochlorine pesticides (OCPs) in the soils and atmosphere of the Punjab province, Pakistan. Atmospheric concentrations of OCPs were estimated by using the polyurethane foam passive air sampling (PUF-PAS) technique. DDTs (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane) and chlordane were the dominant OCPs found in both soil and air samples. The average concentrations of DDTs, HCHs and chlordane were 350, 55 and 99pgm−3 in air and 40, 7.8 and 3.8ngg−1 in soils, respectively. Air–soil exchange of OCPs was estimated by calculating the fugacities in soil and air. Fugacity fraction (ff) values indicate that soils are acting as a secondary source to contaminate the atmosphere at certain sampling stations. [Copyright &y& Elsevier]

Abstract: Chemical contamination of ecosystems is a global issue with evidence that pollutants impact on living organisms in a harmful fashion. Developing sensor approaches that would allow the derivation of biomarkers or signatures of effect in target sentinel organisms and monitor environmental chemical contamination in a high throughput manner is of utmost importance. As biomolecules absorb infrared (IR), signature vibrational spectra related to structure and function can be derived. In light of this, we tested the notion that IR spectra of bird feathers might reflect environmental chemical contaminant exposure patterns. Feathers were collected from monospecific heronries of cattle egret based in two independent locations (Trimu vs. Mailsi) in the Punjab province of Pakistan; these sites were found to differ in their chemical contamination patterns. Feather samples were chemically analyzed for polychlorinated biphenyls, polybrominated diphenyl ethers, organochlorines and heavy metals. Attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy was employed to derive a spectral signature of individual feathers. Resultant IR spectra were then subjected to canonical correspondence analysis (CAA) to determine whether feather spectral signatures correlate to chemical exposure. Additionally, we explored if principal component analysis (PCA) and linear discriminant analysis (LDA) could be applied to distinguish site-specific differences; linear discriminant function (LDF) was also applied to classify sites. The sampled feathers varied in their chemical exposure patterns depending on whether they were sourced from one site associated with heavy metal exposure or the other which suggested high organic pollutant exposures. CCA of chemical and spectral data showed a correlation between spectral signatures and chemical exposure. PCA-LDA readily distinguished feathers from the two different sites. Discriminating alterations were identified and these were associated with protein and lipid regions in IR spectra. Additionally, LDF showed that the classification rate of spectral categories correlated well with the two chemical exposure patterns (93.6% for Trimu feathers and 91.77% for Mailsi feathers). This pilot study suggests that IR spectra derived from feathers reflect background chemical exposure and points to a novel monitoring tool for contamination. [Copyright &y& Elsevier]

Waste dumping sites are considered as significant disposal pathway for waste contaminants including pesticides. In the present study OCPs were analyzed in soils of waste dumping sites of Pakistan. The mean concentrations of OCPs were in the order: ∑DDTs>∑HCHs>∑Endosulfan>∑HCB>Heptachlor. Order of overall ∑OCPs contamination with respect to location was Lahore>Sukkur>Karachi>Kamoki>Faisalabad>Hyderabad>Losar>Gujrat>Peshawar. Distribution of OCPs in solid waste dumping site was mainly influenced by textural classes, input history and pollution source. Soil texture was the dominant factor for retention of OCPs, whereas TOC and black carbon has not significantly impacted the concentrations of OCPs. Diagnostic ratios indicated the historical input, anaerobic degradation pathway and use of technical mixtures of DDTs in majority of waste dumping sites whereas for HCHs recent as well as past usage of technical mixture was prevalent in most of the areas. Regression analysis revealed a weak positive correlation of OCPs with socioeconomic indices (HDI, Population, waste generation) which is linked with history of use of these contaminants in the respective areas. Forecasted waste generation quantity for the year 2026 showed that waste generation amount will get doubled by the year 2026 suggesting the need properly designed waste management system., (Copyright © 2018. Published by Elsevier Inc.)

Lesser Himalayan Region (LHR) is an important mountain ecosystem which supports a wide range of biodiversity for native flora and fauna. Human population in this region is largely dependent upon local sources for their livelihood. Surface soil (n = 32) and sediment (n = 32) were collected from four different altitudinal ranges of LHR and analyzed for priority Polycyclic Aromatic Hydrocarbons (PAHs) recommended by USEPA. Level, sources and distribution pattern of PAHs were assessed in soil and sediments samples collected from four altitudinal zones in LHR. Total PAHs concentration level of PAHs in soil and sediments ranged from 62.79 to 1080 ng g -1 and 14.54-437.43 ng g -1 , respectively. Compositional profile of PAHs in both soil and sediment were dominated by low and medium molecular weight PAHs, ranged from 18.02 to 402.18 ng g -1 in soil and 0.32-96.34 ng g -1 in sediments. In the context of spatial distribution trend, highest mean concentrations of PAHs in soil were recorded in zone D (sites from the rural region) and for sediments highest concentrations were detected at zone A, which includes dam sites. In all four zones, no altitudinal trend of PAHs in soil and sediments was observed. Source apportionment through receptor modelling by positive matrix factorization (PMF) revealed that local sources such as biomass combustion and vehicular emissions are important sources of PAHs in this region. The prevalence of monsoon atmospheric circulation system in LHR implicated that this region is also influenced by medium and long range atmospheric transportation of PAHs from neighboring countries where potential sources and high level of PAHs has been reported., (Copyright © 2018. Published by Elsevier Ltd.)

This study was designed to monitor organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in riverine water of Lesser Himalaya along the altitude. Further, the sediment-water partitioning employing organic carbon and black carbon models were assessed. Results revealed higher water levels of organochlorine pesticides (0.07-41.4 ng L -1 ) and polychlorinated biphenyls (0.671-84.5 ng L -1 ) in Lesser Himalayan Region (LHR) of Pakistan. Spatially, elevated levels were observed in the altitudinal zone (737-975 masl) which is influenced by anthropogenic and industrial activities. Sediment-water partitioning of OCPs and PCBs were deduced using field data by employing one-carbon (f OC K OC ) and two-carbon Freundlich models (f OC K OC + f BC K BC C W nF-1 ). Results suggested improved measured vs predicted model concentrations when black carbon was induced in the model and suggested adsorption to be the dominant mechanism in phase partitioning of organochlorines in LHR.

The present study was conducted to reveal the concentrations and patterns of organochlorines [i.e., organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)] in freshwater fish species collected from four ecologically important sites of the Indus River i.e., Taunsa (TAU), Rahim Yar Khan (RYK), Guddu (GUD) and Sukkur (SUK). In the fish muscle tissues, concentrations of 15 OCPs (∑15OCPs) and 29 PCBs (∑29PCBs) varied between 1.93-61.9 and 0.81-44.2 ng/g wet weight (ww), respectively. Overall, the rank order of OCs was DDTs>PCBs>hexachlorocyclohexanes (HCHs)>chlordanes (CHLs). The patterns of PCBs showed maximum contribution of tri-CBs (59%). Ratios of individual HCH and DDT analytes contributing to the summed values indicated both recent and past use of these chemicals in the region, depending upon fish species. To assess the associated health risks, carcinogenic and non-carcinogenic risks were calculated through hazard ratios (HRs). For carcinogenic risk, HR was >1 at both 50th and 95th percentile concentrations, suggesting that the daily exposure to OCPs and PCBs yields a lifetime cancer risk of 1 in a million. HR for non-cancerous risk was <1 at both the percentiles, signifying no adverse effect by OCs exposure in native population., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this study, regression analysis revealed that TOC is the principal factor in controlling the fate of organo-halogenated contaminants (OHCs: PCBs, PBDEs, OCPs) in Soan River, Pakistan. The OHCs(adsorbed TOC) burial flux (OHCs(adsorbed TOC)Bf; mg/cm(2)·yr) was calculated in the following ranges: ∑PCBs (0.07-0.31), ∑PBDEs (0.005-0.029), ∑HCHs (0.015-0.046) and ∑DDTs (0.007-0.039). Apart from OHCs(adsorbed TOC)Bf, the levels of OHCs were in the following order: PCBs>DDTs>PBDEs>HCH>Chlordane>HCB. PBDEs and PCB congener patterns showed following order respectively: BDE-149>-153>-18>-138>-44 and PCB-149>-153>-18>-138>-44. DDT isomers and metabolites' pattern were p,p'-DDT>p,p'-DDD>p,p'-DDE>o,p'-DDT>o,p'-DDD>o,p'-DDE and HCHs were β-HCH>α-HCH>γ-HCH>δ-HCH. PBDE composition had similarities to penta-BDE and DE-71 mixtures and PCBs with commercial products Aroclor-1254 and -1260. (DDE+DDD)/∑DDTs and p,p'-DDT/p,p'-DDE suggested the recent input of DDTs in sediments while α/γ-HCH indicated past usage of lindane and technical mixtures. Risk assessment suggested that Soan River and its tributaries are potentially at risk against most of the OHCs., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in eleven edible fish species (5 herbivorous and 6 carnivorous) collected from the River Chenab, Pakistan, during 2007-2009. Total OCP and PCB concentrations (ng g(-1) wet weight, ww) ranged between 13-107 (mean: 38) and 3.1-93.7 (mean: 20) for five herbivorous fish species and 21.6-365 (mean: 148) and 2.5-108 (mean: 30) for six carnivorous species, respectively. The trends of detected organochlorine pesticides (OCPs) in fish samples were: DDTs>PCBs>chlordanes>HCHs. The mean concentration(s) (ng g(-1) ww) of OCPs were relatively higher in all fish species collected near industrial areas followed by urban and agricultural areas. Risk assessment of OCPs and PCBs indicated that fish intake may pose health risk to humans with a consumption rate of >8 g/person/day. The hazardous ratios for the 50th and 95th percentile data of OCPs and PCBs in fish exceeded the value of 1, suggesting that the daily exposure to OCPs and PCBs yield a lifetime cancer risk greater than 1 in 10,000., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Concentrations in surface waters (including particulate phase) of the River Chenab ranged from 27-1100 ng L(-1) and 25-1200 ng L(-1) for OCPs and 7.7-110 ng L(-1) and 13-99 ng L(-1) for PCBs during summer and winter, respectively from 2007-2009. DDTs exhibited the highest concentration, followed by HCHs > chlordane > ∑(24)PCBs > ∑other OCPs. Different indicative ratios for organochlorines suggest that current use, long range transport and also past application of these chemicals contribute to the total burden. Statistical analysis highlighted agricultural and industrial activities and municipal waste disposal as main sources of OCPs and PCBs in the riverine ecosystem of the River Chenab. Risk Quotients (RQ(CCCs)) > 10 for DDTs and PCBs levels in collected water samples from the River Chenab suggest that risk from DDTs and PCBs is moderate to severe and fluxes calculated for OCPs and PCBs from the River Chenab to the Indus River were 7.5 tons per year and 1.0 tons per year, respectively.