Spatial distribution and partitioning of polychlorinated biphenyl and organochlorine pesticide in water and sediment from Sarno River and Estuary, southern Italy

Review on analytical methods and occurrence of organic contaminants in continental water sediments

Various industries produce a myriad of synthetic molecules used to satisfy our needs, but all these molecules are likely to reach aquatic environments. The number of organic contaminants found in rivers and lakes continues to rise, and part of this contamination gets transferred into sediments. Analytical methods to detect problematic substances in the environment often use mass spectrometry coupled with chromatography. Here we reviewed a set of 163 articles and compiled the relevant information into a comprehensive database for analysing organic contaminants in continental sediments including suspended particulate matter and surface and bottom sediments in lakes, rivers and estuaries. We found 1204 compounds detected at least once in sediments, and classified them into 11 categories, i.e. hydrocarbons, flame retardants, polychlorinated biphenyls (PCB), plasticizers, per- and poly-fluoroalkyl substances (PFAS), organochlorines (OCP) and other pesticides, pharmaceuticals, hormones, personal care products (PCP), and other contaminants. Concentrations of these compounds varied from a few ng to several mg/kg of dry sediment. Even hydrophilic compounds were detected in high concentrations. Well-known hydrophobic and persistent contaminants tend to be analysed with mass spectrometry coupled to gas chromatography (GC-MS) whereas contaminants of emerging concern (CEC) are usually analysed with liquid chromatography- mass spectrometry (LC-MS). Suspect screening and non-target analysis (NTA), which use high-resolution mass spectrometry, are still scarcely used on sediment but hold promise for gaining deeper knowledge of organic contamination in aquatic environments.

Residual levels, phase distributions, and human health risks of OCPs in the middle reach of the Huai River, China

Are the residues of organochlorine pesticides (OCPs) in freshwater in China still of concern after prohibition and restriction for decades? The scarcity of monitoring data on OCPs in freshwater in China over the past few years has hampered understanding of this issue. In this study, water and suspended particulate matter (SPM) samples were collected from the middle reach of the Huai River for OCP analyses. Residues of ∑OCPs in water and SPM ranged from ND to 8.6 ng L-1 and 0.50 to 179 ng L-1, with mean concentrations of 1.7 ± 1.3 ng L-1 and 6.1 ± 31 ng L-1, respectively. ∑HCHs (α-, β-, γ-, and δ-HCH) and ∑HEPTs (heptachlor and heptachlor epoxide) were the most predominant pesticides in the dissolved phase and SPM, respectively, accounting for 43 ± 35% and 27 ± 29% of ∑OCPs. HCHs and heptachlor epoxide mainly existed in the dissolved phase, while heptachlor mainly existed in SPM. The isomeric composition pattern of HCHs in water differed from that in SPM. Briefly, β-HCH dominated in water, while δ-HCH dominated in SPM. However, the composition pattern of DDT and its metabolites in water was similar to that in SPM. o,p'-DDD and p,p'-DDE dominated in both water and SPM. The ratios of α-/γ-HCH and (DDD + DDE)/DDTs indicated that HCHs and DDTs were mainly derived from historical residues. Risk assessments indicated that OCPs may not pose carcinogenic and non-carcinogenic risks to residents.

Zooplankton as an indicator of the status of contamination of the Mediterranean Sea and temporal trends

Zooplankton has been intensively used as bioindicators of water pollution at global level, however, only few comprehensive studies have been conducted from the Mediterranean Sea and manly dated back to the 1970s. To redress the urgent need for updated data, this study provides information on the presence and levels of contaminants in zooplankton from the Tyrrhenian Sea. Although banned, both PCBs (46.9 ± 37.2 ng g-1) and DDT (8.9 ± 10.7 ng g-1) are still present and widespread, but their contamination appears to be a local problem and to be declining over the past 50 years. Zooplankton accumulates high levels of certain TEs, including Zn (400 ± 388 ppm) and Pb (35.3 ± 45.5 ppm), but shows intermediate concentrations of other TEs, including Cd (1.6 ± 0.9 ppm) and Hg (0.1 ± 0.1 ppm), comparing with both strongly polluted and more pristine marine habitats, which may reflect a general improvement.

The status of organochlorine pesticide contamination in Greek agricultural soils: the ghost of traditional agricultural history

Inadequate information regarding pesticide contamination in Greek agricultural soils is currently available, while national soil monitoring programs have not been initiated yet. The aim of the present study was to assess the levels, compositions, and distribution of thirty three organochlorine pesticides (OCPs) in Greek agricultural soils, due to the environmental threat posed by these compounds, even after decades from their abrogation from the market. Determination of the organochlorine pesticides was achieved using gas-chromatography-mass spectrometry, following a QuEChERS sample preparation method. A total of 60 soil samples, from two soil horizons (up to 60 cm), were obtained from agricultural lands in Greece throughout 2019-2020. The major findings presented DDTs, γ-HCH, alachlor, and 4,4- DCBP in the examined soil samples, with DDTs being the major compounds with their maximum cumulative concentration (ΣDDTs) reaching 1273.4 μg kg-1 d.w. Compositional profile and diagnostic ratios suggested that the occurrence of DDT residues was due to historical inputs. Most of the samples did not exceed the target values set by the Netherlands and Canadian guidelines for DDTs in soil; however, there was one exception in the case of Aegina Island. Finally, based on the environmental exposure assessment conducted, the vast majority of the analytes presented lower concentrations compared to the predicted environmental concentrations, with an exemption for DDE metabolite where the measured and predicted concentrations were almost equal.

Occurrence and Distribution of Persistent Organic Pollutants (POPs) from Sele River, Southern Italy: Analysis of Polychlorinated Biphenyls and Organochlorine Pesticides in a Water-Sediment System

The concentrations, possible sources, and ecological risk of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were studied by analyzing water column (DP), suspended particulate matter (SPM) and sediment samples from 10 sites on the Sele River. Total PCBs concentration ranged from 2.94 to 54.4 ng/L and 5.01 to 79.3 ng/g in the seawater and sediment samples, with OCPs concentration in the range of 0.51 to 8.76 ng/L and 0.50 to 10.2 ng/g, respectively. Pollutants loads in the seaside were measured in approximately 89.7 kg/year (73.2 kg/year of PCBs and 16.5 kg/year of OCPs), indicating that the watercourse could be an important cause of contamination to the Tyrrhenian Sea. Statistical analysis indicates that all polychlorinated biphenyls analytes are more probable to derive from surface runoff than an atmospheric deposition. The results explain that higher concentrations of these pollutants were built in sediment samples rather than in the other two phases, which are evidence of historical loads of PCBs and OCPs contaminants. The Sediment Quality Guidelines (SQGs), the Ecological Risk Index (ERI) and the Risk Quotient (RQ) show that the Sele river and its estuary would reputedly be a zone possibly at risk.

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.

Occurrence, origin and potential ecological risk of dissolved polycyclic aromatic hydrocarbons and organochlorines in surface waters of the Gulf of Gabès (Tunisia, Southern Mediterranean Sea)

We investigated the occurrence, origin, and potential ecological risk of dissolved polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCBs) and organochlorine pesticides (OCPs) in 27 surface water samples collected from a highly anthropized and industrialized area in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea) in October-November 2017. The results demonstrated a wide range of concentrations (ng L^-1) with the following decreasing order: Ʃ16 PAHs (17.6-71.2) > Ʃ20 PCBs (2.9-33.7) > Ʃ6 DDTs (1.1-12.1) > Ʃ4 HCHs (1.1-14.8). Selected diagnostic ratios indicated a mixture of both pyrolytic and petrogenic sources of PAHs, with a predominance of petrogenic sources. PCB compositions showed distinct contamination signatures for tetra- to hepta-chlorinated PCBs, characteristic of contamination by commercial (Aroclor) PCB mixtures. The dominant OCP congeners were γ-HCH, 2,4'-DDD and 2,4'-DDE, reflecting past use of Lindane and DDTs in the study area. Agricultural, industrial and domestic activities, as well as atmospheric transport are identified as potential sources of PAHs, PCBs and OCPs in surface waters of the Gulf of Gabès. Toxic equivalents (TEQs) suggested a low carcinogenic potential for PAHs in seawater samples (mean of 0.14 ng TEQ L^-1). Evaluation of risk coefficients revealed low risk for PAHs and PCBs, and moderate to severe risk for OCPs.

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.

Seasonal variation of pesticides in surface water and drinking water wells in the annual cycle in western Poland, and potential health risk assessment

Drinking water wells on a riverbank filtration sites are exposed to contamination from farmlands (like pesticides) that had migrated from the contaminated river. In this study, pesticide contamination of the Warta River and riverbank filtration water at the Mosina-Krajkowo well field (Poland) were examined during the annual cycle. Among the 164 pesticides analysed, 25 were identified. The highest concentrations occurred in the river water and decreased along the flow path from the river to wells. Only the most persistent substances were detected at the farthest points. During the study, seasonal changes in pesticide concentrations and differences in the types of occurring substances were observed. Most substances and the highest concentrations were detected in May 2018, while the lowest number and the lowest concentrations were detected in February 2018. Spring is the period of increased exposure of water to pollution, which is correlated with increased pesticides use and increased rainfall. Seven toxic and persistent pesticides were found with the highest concentrations in water: isoproturon, nicosulfuron, imidacloprid, terbuthylazine, chlorotoluron, S-metalachlor, and prometryn. Pesticides are widely used in the study area; therefore, a potential health risk assessment was performed. The hazard quotient (HQ) values did not exceed one, which indicated a less significant health risk.

Organochlorine Pesticides and Polychlorinated Biphenyls in Sediment Impacted by Cage Aquaculture in the Volta Basin of Ghana

Seventeen organochlorine pesticides (OCPs) and seven indicator polychlorinated biphenyls (PCBs) residues in 80 sediment samples from four cage aquaculture farms on the Volta Basin were determined to find out the extent of their contamination as well as their risk to biota in the aquatic ecosystem. The extracted residues of the OCPs and PCBs were analysed on a gas chromatograph equipped with an electron capture detector and mass spectrometer, respectively. Eleven (11) OCPs: methoxychlor, δ-HCH, o,p'-DDD, α-endosulphan, β-HCH, o,p-DDE, p,p-DDE, p,p'-DDT, β-endosulphan, endrin, and heptachlor and seven (7) PCBs: PCB 18, PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, and PCB 180 were detected in the sediments from the farms. The OCPs level ranged < LOD - 33.0 µg/kg. δ-HCH (8.154 ± 0.414 µg/kg), α-endosulphan (6.000 ± 1.414 µg/kg), o,p'-DDD (2.010 ± 1.46 µg/kg), endrin (13.867 ± 8.716 µg/kg), and α-endosulphan (0.503 ± 0.398 µg/kg) were predominant with frequencies of detection 100%, 45%, 68%, 92%, and 25% in fish farms A, B, C, D and controls, respectively. PCBs concentrations ranged 0.042-5.320 ng/g wet weight. PCB 153 recorded the highest concentration of 3.328 ± 1.700 ng/g in farm D. PCB 18 and PCB 180 dominated the profiles in the sediment from all the farms. The ecotoxicological risk of the OCPs and PCBs in the surface sediment using the SQGs indicated that ∑HCH in the sediment from all the farms except that the controls may pose a health risk to the benthic organisms. Therefore, a comprehensive remedial intervention is required to arrest the situation.

A translocation analysis of organophosphate pesticides between surface water, sediments and tissues of common reed Phragmites australis

This study investigated the ability of common reed, Phragmites australis to take up organophosphate pesticides (OPPs). The study site was the agriculturally polluted Sundays Estuary in South Africa. Surface water, leaves, roots, and deep-rooted-sediments of P. australis were collected along the length of the estuary and analysed for 13 different OPPS. The extraction of OPPs in plant tissues was performed by QuEChERS method followed by GC-MS analysis. The highest concentration of OPPs was found in leaves (16.41-31.39 μg kg^-1 dw), followed by roots (13.92-30.88 μg kg^-1 dw), and sediments (3.30-8.07 μg kg^-1 dw). Of the 13 targeted OPPs, only one compound was not detected across the four sample matrices, thus reflecting widespread contamination in the Sundays Estuary. The biota sediment accumulation factor (BSAF) values of pyraclofos, quinalphos, fenitrothion, phosalone, EPN, diazinon, chlorpyrifos, pyrazophos, and isazophos were higher than one implying that P. australis possesses the ability to bioaccumulate these compounds. The root-leaf translocation factors (TF_r-l) of these pesticides were higher than 1, suggesting that P. australis possesses the capacity to move these pesticides from roots to leaves. The insignificant correlation observed between log BSAF and log K_ow and log TF_r-l and log K_ow implies that OPPs uptake by P. australis tissues were not dependent on log Kow. Our study demonstrates that P. australis possesses the potential to effectively remove OPPs from contaminated water and sediment.

Residues of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in waters of the Ili-Balkhash Basin, arid Central Asia: Concentrations and risk assessment

Release and transport of contaminants in watersheds can have adverse effects on aquatic organisms and human health. Little attention, however, has been paid to chemical contamination of aquatic environments in arid regions by persistent organic pollutants. We analyzed the concentrations and distributions of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in waters of the Ili-Balkhash Basin, in arid central Asia. ΣOCP concentrations ranged from 4.02 to 122.80 ng L^-1 and ΣPAH concentrations were between 7.58 and 70.98 ng L^-1. On a global scale, OCP and PAH concentrations in waters of the Ili-Balkhash system were relatively low, with only a few exceptions, i.e., highest concentrations near cities and relatively high values in some headwater areas. Source identification revealed that the dichlorodiphenyltrichloroethanes (DDTs) may come from recent use, whereas endosulfans stem from historic applications. Lindane, a common insecticide, may be responsible for hexachlorocyclohexanes (HCHs). Low-molecular-weight PAHs, primarily originating from wood and coal combustion and petroleum-derived sources, were the primary components of PAHs in waters. Furthermore, the primary sources of PAHs at different sites were identified using a Positive Matrix Factorization model: 1) oil leakage (33.9%), 2) biomass burning (29.5%), 3) coal combustion (22.6%), and 4) petroleum-powered vehicles (14.1%). Agricultural, industrial and domestic activities are all potential pollution sources. Besides, contaminated headwater areas indicate that long-range transport has probably become a non-negligible mechanism for pollutant distribution. Risk assessment showed low to moderate toxicity for aquatic organisms, but no marked carcinogenic or non-carcinogenic risks for human health.

Occurrence and partition of organochlorine pesticides (OCPs) in water, sediment, and organisms from the eastern sea area of Shandong Peninsula, Yellow Sea, China

To evaluate the occurrence and partition of organochlorine pesticides (OCPs), hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), water, sediment, and organisms were sampled from the eastern sea area of Shandong Peninsula (Yellow Sea, China) across all four seasons in 2016. There were three OCP hotspots in the sediment, mainly caused by the transportation of lindane and dicofol from adjacent Swan Lake and Guhe River. Waterborne OCP levels were highest in winter and lowest in spring, without vertical variability, suggesting that the Yellow Sea Cold Water Mass was governing the spatio-temporal distribution of OCPs in seawater. There was substantial accumulation of HCHs and DDTs in organisms via sediment, as indicated by the relatively low fraction of sedimental fugacity, high bio-sediment accumulation factor, and a positive linear correlation between logΣHCHs and trophic level. This is the first study that has focused on the accumulation of OCPs in entire sediment-seawater-organism system involving multi-phyla of species.

A Relevant Screening of Organic Contaminants Present on Freshwater and Pre-Production Microplastics

Microplastics (MPs) have recently been discovered as considerable pollutants of all environmental matrices. They can contain a blend of chemicals, some of them added during the manufacture of plastic to improve their quality (additives) and others adsorbed from the surrounding environment. In light of this, a detailed study about the identification and quantification of target organic pollutants and qualitative screening of non-target compounds present on MPs was carried out in different types of samples: environmental MPs, collected from an Italian river, and pre-production MPs, taken from the plastic industry. Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs) were chosen as target compounds to be quantified by Gas Chromatography-Mass Spectrometry (GC–MS), while the non-target screening was carried out by High Resolution Gas Chromatography-Mass Spectrometry (HRGC–MS). The target analysis revealed concentrations of 16 priority Polycyclic Aromatic Hydrocarbons by Environmental Protection Agency (EPA-PAHs) in the range of 29.9–269.1 ng/g; the quantification of 31 PCBs showed values from 0.54 to 15.3 ng/g, identifying CB-138, 153, 180, 52, and 101 primarily; and the detected OCPs (p,p’-DDT and its metabolites) ranged between 14.5 and 63.7 ng/g. The non-target screening tentatively identified 246 compounds (e.g., phthalates, antioxidants, UV-stabilizers), including endocrine disruptors, toxic and reprotoxic substances, as well as chemicals subjected to risk assessment and authorisation. The large assortment of plastic chemicals associated with MPs showed their role as a presumable source of pollutants, some of which might have high bioaccumulation potential, persistence, and toxicity.

History traces of HCHs and DDTs by groundwater dating and their behaviours and ecological risk in northeast China

Organochlorine pesticides legacies, such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), remained in sediments or soils due to their difficulty in decomposition, especially in the agricultural areas where pesticides were widely used historically. Different from the little disturbed depositional environment of lake, it was difficult for rivers to explore the timing of DDT and HCH inputs through dating sediment cores as records. Based on groundwater dating, this study ascertained the historic pollution of DDT and HCH in Taizi River basin. HCH and DDT residues in groundwater were consistent with the historical production and usage, which increased from the 1950s to the 1980s and declined from the 1980s to the 1990s. Moreover, the partitioning behaviours of HCHs and DDTs in surface water and suspended particulate matter were discussed. It was revealed that β-HCH and o,p'-DDT were more likely to attach to suspended particulate matter than other isomers. Furthermore, species sensitivity distribution curves were generated using 54 toxicity data records to assess the risk of HCHs and DDTs in water and suspended particulate matter. These results indicated that p,p'-DDT in surface water posed a high risk to 95% of the aquatic life in the long run.

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

The emission of polychlorinated biphenyls (PCBs) in South Asian countries is one of the great environmental concerns and has resulted in the contamination of surrounding high altitude regions such as Azad Jammu and Kashmir (AJK), Pakistan. This first investigation of Polychlorinated Biphenyl (PCBs) concentrations in the ambient air, water and surface soil was conducted along the extensive stream network in the AJK valley of the Himalayan Region. In 2014, surface soil samples were taken and passive air and water samplers were deployed along the four main rivers, namely Jhelum, Neelum, Poonch and Kunhar, and analysed for PCBs (33 congeners) using GC-MS/MS. The ∑₃₃PCBs concentrations ranged from 31.17 to 175.2 (mean ± SD: 81 ± 46.4 pg/L), ND to 1908 (1054 ± 588.5 pg/g), and 29.8 to 94.4 (52.9 ± 22.7 pg/m³) in surface water, soil and air matrices, respectively. The levels of dioxin-like PCBs (∑₈DL-PCBs) contributed considerably towards the total PCBs concentrations: 60.63% (water), 43.87% (air) and 13.76% (soil). The log transformed air-water fugacity (log fa/fw) ratios ranged from -9.37 to 2.58; with 86.3% of the sampling sites showing net volatilization of selected PCB congeners. Similarly, the fugacity fractions for air-soil exchange exhibited narrow variation (0.8 to < 1) indicating net volatilization of PCBs. The ecological risk assessment showed low potential ecological risks (E_rⁱ  = 1.58-7.63) associated with PCB contamination. The present findings provide baseline data that suggest cold trapping of POPs in the remote mountainous areas of Pakistan and can support environmental management of POPs at the regional level. This pioneer investigation campaign to assess the PCBs concentrations in Himalayan Riverine Network of Azad Jammu and Kashmir, Pakistan helps to develop baseline data of PCBs from the strategically important riverine environment that would help in future regional as well as global ecological studies. However, the effects of temperature variations on the sampling rates of chemicals across a wide spectrum of volatility along the elevation gradient were not taken under consideration for PCBs atmospheric concentrations.

Persistent organic pollutants are still present in surface marine sediments from the Seto Inland Sea, Japan

Although persistent organic pollutants (POPs) are currently banned or strictly controlled under the Stockholm Convention on Persistent Organic Pollutants, POPs are still distributed worldwide due to their environmental persistence, atmospheric transport, and bioaccumulation. Herein we investigated the current concentrations of POPs in the sediments from Seto Inland Sea, Japan and sought to clarify the factors currently controlling the POPs concentration of the surface sediments from Seto Inland Sea. The concentrations of hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), and chlordane isomers (CHLs) in sediments from Seto Inland Sea were <0.002-1.20 ng g^-1, 0.01-2.51 ng g^-1, and 0.01-0.48 ng g^-1, respectively. Resuspension increased the concentrations of HCHs, HCB, and DDTs in the surface sediment with the release of historically contaminated pollutants accumulated in a lower layer. We speculate that CHLs in air that were removed by atmospheric deposition affects the concentration of CHLs in surface sediments.

Occurrence and risk evaluation of organochlorine contaminants in surface water along the course of Swartkops and Sundays River Estuaries, Eastern Cape Province, South Africa

Organochlorine contaminants were analysed in surface water from Sundays (SDE) and Swartkops Estuaries (SWE), Eastern Cape Province, which is among the largest estuaries in South Africa. The concentration of Σ₁₈OCPs ranged from 16.7 to 249.2 ng/L in autumn, 19.9-81.4 ng/L in winter, 43.6-126.8 ng/L in spring and 68.3-199.9 ng/L in summer for SDE, whereas in SWE, the values varied from 20.9 to 259.7 ng/L in autumn, 58.9-263.9 ng/L in winter, 3.2-183.6 ng/L in spring and 118.0-188.9 ng/L in summer. Among all OCPs, α-HCH, β-HCH, p,p'-DDE, p,p'-DDT, endrin, dieldrin and endrin aldehyde were predominant in surface water samples from SDE and SWE. Furthermore, the mean concentration of polychlorinated biphenyls (PCBs) ranged from 126.7 ng/L in winter to 151.0 ng/L in spring for SDE and 249.0 ng/L in spring to 727.6 ng/L in winter for SWE. Tri- and tetra-PCBs dominated the PCB homologue profile. Hierarchical cluster analysis grouped the study sites into three regions from least polluted to most polluted, indicated that SWE is more polluted compared to SDE, probably due to the influx of agricultural and industrial effluents. Carcinogenic and non-carcinogenic risk assessment revealed that the water from both estuaries is not safe for drinking, although suitable for bathing.

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 10.05 ng L^-1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53 ng 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.

Analysis of organochlorine pesticides in surface water of the Songhua River using magnetoliposomes as adsorbents coupled with GC-MS/MS detection

A simple and effective method based on magnetic separation has been developed for the extraction of organochlorine pesticides (OCPs) from river water samples using magnetoliposomes as adsorbents. This method avoided the time-consuming column passing process of loading large volume samples in traditional SPE through the rapid isolation of magnetoliposomes with an adscititious magnet. Lipid bilayers formed on the surface of Fe₃O₄ showed great adsorptive tendency towards analytes through hydrophobic interactions, and zwitterions headgroups endowed the outer surface of magnetoliposomes with hydrophilicity to improve the dispersing property of adsorbents in the sample matrix. The target analytes were detected by gas chromatography-tandem mass spectrometry, and the limits of detection obtained are in the range of 0.04-0.35ngL^-1. The relative standard deviations of intra- and inter-day are in the range of 2-5% and 4-7%, respectively. The proposed method was employed for analysis of six OCPs in the surface water samples from two cities along the Songhua River in different seasons. Compared with the traditional methods, the proposed method could reduce the consumption of the organic solvent and shorten the sample preparation time.

A review on environmental monitoring of water organic pollutants identified by EU guidelines

The contamination of fresh water is a global concern. The huge impact of natural and anthropogenic organic substances that are constantly released into the environment, demands a better knowledge of the chemical status of Earth's surface water. Water quality monitoring studies have been performed targeting different substances and/or classes of substances, in different regions of the world, using different types of sampling strategies and campaigns. This review article aims to gather the available dispersed information regarding the occurrence of priority substances (PSs) and contaminants of emerging concern (CECs) that must be monitored in Europe in surface water, according to the European Union Directive 2013/39/EU and the Watch List of Decision 2015/495/EU, respectively. Other specific organic pollutants not considered in these EU documents as substances of high concern, but with reported elevated frequency of detection at high concentrations, are also discussed. The search comprised worldwide publications from 2012, considering at least one of the following criteria: 4 sampling campaigns per year, wet and dry seasons, temporal and/or spatial monitoring of surface (river, estuarine, lake and/or coastal waters) and ground waters. The highest concentrations were found for: (i) the PSs atrazine, alachlor, trifluralin, heptachlor, hexachlorocyclohexane, polycyclic aromatic hydrocarbons and di(2-ethylhexyl)phthalate; (ii) the CECs azithromycin, clarithromycin, erythromycin, diclofenac, 17α-ethinylestradiol, imidacloprid and 2-ethylhexyl 4-methoxycinnamate; and (iii) other unregulated organic compounds (caffeine, naproxen, metolachlor, estriol, dimethoate, terbuthylazine, acetaminophen, ibuprofen, trimethoprim, ciprofloxacin, ketoprofen, atenolol, Bisphenol A, metoprolol, carbofuran, malathion, sulfamethoxazole, carbamazepine and ofloxacin). Most frequent substances as well as those found at highest concentrations in different seasons and regions, together with available risk assessment data, may be useful to identify possible future PS candidates.

Biomonitoring of nutrient and toxic element concentrations in the Sarno River through aquatic plants

The Sarno River is considered the most polluted river in Europe and one of the ten most polluted rivers in the world. So far, its quality has been usually evaluated by water and sediment analyses of either inorganic or organic pollutants. However, a biomonitoring approach would be of paramount importance in the evaluation of river quality, since it integrates pollutant temporal fluctuations, as in the case of discontinuous inputs from urban, industrial and agricultural activities. To this end, a passive biomonitoring study of the Sarno River was carried out, using two native aquatic plants accumulators of inorganic pollutants. The spring area was monitored analysing the roots of the semi-submerged Apium nodiflorum, whereas the whole river course was monitored analysing the shoots of the submerged Potamogeton pectinatus. The information on the four macronutrient (Ca, K, Mg, P), the six micronutrient (Cu, Fe, Mn, Na, Ni, Zn) and the four toxic element (Cd, Cr, Pb, V) concentrations were separately combined in the Nemerow Pollution Index. Results evidenced a severe pollution degree of the Sarno River, attributable to toxic elements > micronutrients > macronutrients. In particular, the spring area showed high K concentrations, as well as high concentrations of several micronutrients and toxic elements. A generalized Zn contamination and a progressive macronutrient (above all Ca and P), micronutrient (above all Ni, Cu and Fe) and toxic element (above all Cr and Pb) accumulation toward the mouth was related to pollution from agricultural and urban activities. Industrial sources, especially tanneries along the Solofrana tributary, accounted for high Mn concentrations, whereas the volcanic origin of the substrate accounted for a generalized V contamination.

Risk assessment of an organochlorine pesticide mixture in the surface waters of Qingshitan Reservoir in Southwest China

Risk assessment of single pollutants has been extensively studied. However, the co-exposure of pollutants in a real environment may pose a greater risk than single chemicals. In this study, concentration addition-based risk quotients were applied to the risk assessment of the 15 organochlorine pesticides (OCPs) mixtures (α-hexachlorocyclohexane (HCH), β-HCH, γ-HCH, δ-HCH, heptachlor, aldrin, heptachlor epoxide, chlordane, α-endosulfan, p,p′-dichloro-diphenyl-dichloroethylene, endrin, β-endosulfan, p,p′-dichloro-diphenyl-dichloroethane, p,p′-dichloro-diphenyl-trichloroethane, and methoxychlor) detected in the surface water (reservoirs, ponds, and streams) of Qingshitan Reservoir in Southwest China from 2014 to 2016 by summing up the toxic units (RQ_STU) of the toxicity data from the individual chemicals. The RQ_STU of the OCPs mixture exceeded 1 in 45.23% of the 283 surface water samples based on acute data and an assessment factor of 100, indicating a potential risk for the aquatic environment (fish). Methoxychlor and γ-HCH contributed the most toxicities in the pesticide mixtures toward Daphnia and fish and provided at least 50% of the mixture toxicity in all samples with RQ_STU larger than 1. The most sensitive organism to realistic OCPs mixtures in the surface waters of Qingshitan Reservoir was fish, followed by Daphnia and algae. The values of the maximum cumulative ratio for all samples indicated that the risk assessment based on single chemicals underestimated the pesticide mixture toxicities, which shows that special consideration should be made for the ecological risk of pesticide mixtures in the aquatic environment.

Risk assessment of single pollutants has been extensively studied.

Pollution characteristics and ecological risk assessment of HCHs and DDTs in estuary wetland sediments from the Bohai Bay, North China

Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) tend to persist in the environment for long periods of time. The concentration and distribution of HCHs and DDTs were investigated in surface sediments of Yongdingxinhe wetland and Binhai wetland by gas chromatography-mass spectrometer (GC-MS). All isomers of HCHs and DDTs were detected in all of the samples. The concentrations of total HCHs (ΣHCHs) in two wetland sediments ranged from 69.81 to 379.28 ng · g ^-1, with a mean value of 224.55 ng · g ^-1. The concentrations of total DDTs (ΣDDTs) ranged from 98.32 to 129.10 ng · g ^-1, with a mean value of 113.71 ng · g ^-1. The results of an ecological risk assessment demonstrated that there was high-risk ecological effect of organochlorine pesticides (OCPs) on the estuary wetlands. Lindane and technical DDTs were found to be the main sources of OCPs.

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.

The evolution of pollution profile and health risk assessment for three groups SVOCs pollutants along with Beijiang River, China

Three important groups of semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), organic chlorinated pesticides (OCPs) and phthalate esters (PAEs), were produced by various human activities and entered the water body. In this study, the pollution profiles of three species including 16 PAHs, 20 OCPs and 15 PAEs in water along the Beijiang River, China were investigated. The concentrations of Σ₁₆PAHs in the dissolved and particulate phases were obtained as 69-1.5 × 10² ng L^-1 and 2.3 × 10³-8.6 × 10⁴ ng g^-1, respectively. The levels of Σ₂₀OCPs were 23-66 ng L^-1 (dissolved phase) and 19-1.7 × 10³ ng g^-1 (particulate phase). Nevertheless, higher levels of PAEs were found both in the dissolved and particulate phases due to abuse use of plastic products. Furthermore, non-cancer and cancer risks caused by these SVOCs through the ingestion absorption and dermal absorption were also assessed. There was no non-cancer risk existed through two kinds of exposure of them at current levels, whereas certain cancer risk existed through dermal absorption of PAHs in the particulate phase in some sampling sites. The results will show scientific insights into the evaluation of the status of combined pollution in river basins, and the determination of strategies for incident control and pollutant remediation.

Residues of hexachlorobenzene and chlorinated cyclodiene pesticides in the soils of the Campanian Plain, southern Italy

A systematic grid sampling method and geostatistics were employed to investigate the spatial distribution, inventory, and potential ecological and human health risks of the residues of hexachlorobenzene (HCB) and chlorinated cyclodiene pesticides in soils of the Campanian Plain, Italy, and explore their relationship with the soils properties. The geometric mean (Gmean) concentrations of HCB and cyclodiene compounds followed the order CHLs (heptachlor, heptachlor epoxide, trans-chlordane, and cis-chlordane) > DRINs (aldrin, dieldrin, and endrin) > SULPHs (α-endosulfan, β-endosulfan, and endosulfan sulfate) > HCB. The residual levels of most cyclodienes in agricultural soils were generally higher than those of corresponding counterparts in the other land uses. Significant differences in the concentration of HCB and cyclodienes in the soils across the region are observed, and the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) areas exhibit particularly high residual concentrations. Some legacy cyclodienes in the Campanian Plain may be attributed to a secondary distribution. The Gmean inventory of HCB, SULPHs, CHLs, and DRINs in the soil is estimated to be 0.081, 0.41, 0.36, and 0.41 metric tons, respectively. The non-cancer and cancer risks of HCB and cyclodienes for exposed populations are deemed essentially negligible, however, endosulfan poses significant ecological risks to some terrestrial species.

Polychlorinated biphenyls and organochlorine pesticides in surface sediments from Shantou Bay, China: Sources, seasonal variations and inventories

Sediments from Shantou Bay, China, were analyzed for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) for the first time. The concentrations of PCBs and OCPs were 0.54-55.5ngg^-1 and 2.19-16.9ngg^-1 (dry weight), respectively. Source identification showed that tri-CBs and penta-CBs were manufactured and used in the last century, while usage of antifouling paint might still serve as a significant source of sediment DDT. Concentrations of PCBs and HCHs significantly (p<0.05) increased after wet season, suggesting that atmospheric deposition and surface runoff played an important role in distribution of historical pollutants. Additionally, the adverse biological effects could occasionally occur for DDT in sediments. The mass inventories were preliminarily calculated for PCBs (90.1ngcm^-2 and 0.09tons) and OCPs (61.8ngcm^-2 and 0.062tons) in Shantou Bay, while as part of the "reservoir" of organochlorine compounds to the global ocean, its role cannot be neglected.

Organochlorine pesticides and polychlorinated biphenyls in surface water around Beijing

Contaminant concentrations, sources, seasonal variation, and eco-toxicological risk of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface water around Beijing from summer to winter in 2015 and 2016 were investigated. The concentrations of ∑OCPs and ∑PCBs ranged from 9.81 to 32.1 ng L^-1 (average 15.1 ± 7.78 ng L^-1) and from 7.41 to 54.5 ng L^-1 (average 21.3 ± 1.87 ng L^-1), respectively. Hexachlorocyclohexane (HCHs) were the dominated contamination both in aqueous and particulate phase. For PCBs, lower chlorinated PCBs were the major contaminants. Compositions of HCHs, dichlorodiphenyltrichloroethane (DDTs), and PCBs indicated that the sources of OCPs and PCBs in water were due to historical usage in the study areas. For OCPs, there was an obvious variation among three seasons, while insignificant change was shown for PCBs. Water quality standards for China's surface water were not exceeded in this study. Concentrations at Miyun Reservoir, the primary source of drinking water to Beijing, when compared to the USEPA's criterion for cancer risk was below the level of risk.

Estimation of heavy metal loads from Tiber River to the Tyrrhenian Sea and environmental quality assessment

In order to evaluate the heavy metal pollution in the Tiber River and its environmental impact on the Tyrrhenian Sea (Central Mediterranean Sea), eight heavy metals (As, Hg, Cd, Cr, Cu, Ni, Pb and Zn) were determined in the water dissolved phase, suspended particulate matter and sediment samples collected from 21 sites in different seasons. Total heavy metal concentrations ranged from 34.88 to 4201.23 μg L^-1 in water (as the sum of the water dissolved phase and suspended particulate matter) and from 42.81 to 1686.84 mg kg^-1 in sediment samples. The total selected heavy metal load contribution into the sea is calculated in about 21,257.85 kg year^-1, showing that this River should account as one of the main contribution sources of heavy metals in the Mediterranean Sea. In relation to the ecological assessment, the Tiber River and Estuary would be considered as an area in which the ecological integrity is possibly at risk.

Polychlorinated biphenyls and organochlorine pesticides in Tiber River and Estuary: Occurrence, distribution and ecological risk

The polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) pollution in the Tiber River and its environmental impact on the Tyrrhenian Sea (Central Mediterranean Sea) were estimated. 32 PCBs and 17 OCPs (aldrin, α-BHC, β-BHC, δ-BHC, lindane, p,p'-DDD, p,p'-DDE, p,p'-DDT, dieldrin, endosulfan I, endosulfan II, endosulfan sulfate, endrin, endrin aldehyde, heptachlor, heptachlor epoxide, methoxychlor) were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediment samples. Total concentrations of PCBs ranged from 0.54 to 74.75ngL(-1) in water (sum of DP and SPM) and from 3.73 to 79.30ngg(-1) dry weigh in sediment samples; while the concentrations of total OCPs collected in water (sum of DP and SPM) ranged from 0.07 to 7.04ngL(-1) and from 0.66 to 10.02ngg(-1) dry weigh in sediment samples. Contaminant discharges into the sea were calculated in about 227.08kgyear(-1) for PCBs and 24.91kgyear(-1) for OCPs, showing that this river should account as one of the main contribution sources of PCBs and OCPs to the Tyrrhenian Sea. The ∑TEQPCB from the sediment samples ranged from 0.0006 to 0.37ngg(-1) with an average level of 0.13ngg(-1). Based on Sediments Quality Guidelines, biological adverse effects on aquatic ecosystem were rare to occasional for PCB and OCP levels in Tiber water system.

Contamination characteristics of organochlorine pesticides in multimatrix sampling of the Hanjiang River Basin, southeast China

Hanjiang River, the second largest river in Guangdong Province, Southern China, is the primary source of drinking water for the cities of Chaozhou and Shantou. Our previous studies indicated that soils from an upstream catchment area of the Hanjiang River are moderately contaminated with organochlorine pesticides (OCPs), which can easily enter the river system via soil runoff. Therefore, OCPs, especially downstream drinking water sources, may pose harmful health and environmental risks. On the basis of this hypothesis, we measured the OCP concentrations in dissolved phase (DP), suspended particle matter (SPM), and surface sediment (SS) samples collected along the Hanjiang River Basin in Fujian and Guangdong provinces. OCP residue levels were quantified through electron capture detector gas chromatography to identify the OCP sources and deposits. The concentration ranges of OCPs in DP, SPM, and SS, respectively, were 2.11-12.04 (ng/L), 6.60-64.77 (ng/g), and 0.60-4.71 (ng/g) for hexachlorocyclohexanes (HCHs), and 2.49-4.77 (ng/L), 6.75-80.19 (ng/g), and 0.89-252.27 (ng/g) for dichloro-diphenyl-trichloroethanes (DDTs). Results revealed that DDTs represent an ecotoxicological risk to the Hanjiang River Basin, as indicated by international sediment guidelines. This study serves as a basis for the future management of OCP concentrations in the Hanjiang River Basin, and exemplifies a pattern of OCP movement (like OCP partition among multimedia) from upstream to downstream. This pattern may be observed in similar rivers in China.

The status of organochlorine pesticide contamination in the soils of the Campanian Plain, southern Italy, and correlations with soil properties and cancer risk

The distribution, inventory, and potential risk of organochlorine pesticides (OCPs), including Hexachlorocyclohexanes (HCHs) and Dichlorodiphenyltrichloroethanes (DDTs), and their correlation with soil properties and anthropogenic factors were investigated in soils of the Campanian Plain. The total concentrations of HCHs and DDTs ranged from 0.03 to 17.3 ng/g (geometric mean: GM = 0.05 ng/g), and 0.08-1231 ng/g (GM = 14.4 ng/g), respectively. In general, the concentration of OCPs in farmland and orchards was higher than on land used for non-agricultural purposes. There are significant differences in the concentration of OCPs in the soils across the region, more specifically, the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) are recognized as severely OCP-contaminated areas. The recent application of technical HCHs and DDTs in large quantities appears unlikely in light of the ratio of α-HCH/β-HCH and p,p'-DDT/p,p'-DDE, and the prohibition of the use of these chemicals in Italy nearly forty years ago. The clear correlation between the concentration of DDTs and organic carbon suggests a typical secondary distribution pattern. The mass inventory of OCPs in soils of the Campanian Plain is estimated to have a GM of 17.3 metric tons. There is no clear evidence linking the impact of geographical distribution of OCPs on the incidence of cancer, and the 95% confidence interval of total incremental lifetime cancer risk (TILCR) data falls below the internationally accepted benchmark value of 1 × 10(-5).

In situ bioavailability of DDT and Hg in sediments of the Toce River (Lake Maggiore basin, Northern Italy): accumulation in benthic invertebrates and passive samplers

DDT and mercury (Hg) contamination in the Toce River (Northern Italy) was caused by a factory producing technical DDT and using a mercury-cell chlor-alkali plant. In this study, DDT and Hg contamination and bioavailability were assessed by using different approaches: (1) direct evaluation of sediment contamination, (2) assessment of bioaccumulation in native benthic invertebrates belonging to different taxonomic/functional groups, and (3) evaluation of the in situ bioavailability of DDT and Hg using passive samplers. Sampling sites were selected upstream and downstream the industrial plant along the river axis. Benthic invertebrates (Gammaridae, Heptageniidae, and Diptera) and sediments were collected in three seasons and analyzed for DDT and Hg content and the results were used to calculate the biota sediment accumulation factor (BSAF). Polyethylene passive samplers (PEs) for DDT and diffusive gradients in thin films (DGTs) for Hg were deployed in sediments to estimate the concentration of the toxicants in pore water. Analysis for (DDx) were performed using GC-MS. Accuracy was within ±30 % of the certified values and precision was >20 % relative standard deviation (RSD). Total mercury concentrations were determined using an automated Hg mercury analyzer. Precision was >5 % and accuracy was within ±10 % of certified values. The results of all the approaches (analysis of sediment, biota, and passive samplers) showed an increasing contamination from upstream to downstream sites. BSAF values revealed the bioavailability of both contaminants in the study sites, with values up to 49 for DDx and up to 3.1 for Hg. No correlation was found between values in sediments and the organisms. Concentrations calculated using passive samplers were correlated with values in benthic invertebrates, while no correlation was found with concentrations in sediments. Thus, direct analysis of toxicant in sediments does not provide a measurement of bioavailability. On the contrary, analysis of bioaccumulation in benthic organisms provides the most realistic picture of the site-specific bioavailability of DDx and Hg, but this approach is time-consuming and not always feasible. On the other hand, the in situ deployment of passive samplers proved to be a powerful tool, providing a good surrogate measure of bioaccumulation.

Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in sediments from the Yellow and Yangtze Rivers, China

Polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are toxic environmental pollutants that are often found in sediments. The Yangtze and Yellow rivers in China are two of the largest rivers in Asia and are therefore important aquatic ecosystems; however, few studies have investigated the PCDD/F and PCB content in the sediments of these rivers. Accordingly, this study was conducted to generate baseline data for future environmental risk assessments. In the present study, 26 surface sediments from the middle reaches of the Yellow and Yangtze rivers were analyzed for PCDD/Fs and dioxin-like (dl) PCBs by high-resolution gas chromatography and high-resolution mass spectrometry. The ranges of PCDD/F, dl-PCB, and WHO-TEQ content in sediments from the Yellow River were 2.1-19.8, 1.11-9.9, and 0.08-0.57 pg/g (dry weight), respectively. The ranges of PCDD/F, dl-PCB, and WHO-TEQ content in sediments from the Yangtze River were 6.1-84.9, 1.8-24.1, and 0.13-0.29 pg/g (dry weight), respectively. Total organic carbon and dl-PCB contents in the Yellow River were significantly correlated (Spearman's correlation coefficient, r = 0.64, P < 0.05). It is well known that total organic carbon plays a role in the transport and redistribution of dl-PCB. Principal component analysis indicated that PCDD/Fs may arise from pentachlorophenol, sodium pentachlorophenate, and atmospheric deposition, while dl-PCBs likely originate from burning of coal and wood for domestic heating. The dioxin levels in the river sediments examined in this study were relatively low. These findings advance our knowledge regarding eco-toxicity and provide useful information regarding contamination sources.

Nano-occurrence and removal of PCBs within the Europe's largest petrochemical MBR system

The occurrence of 45 PCBs was studied in a wastewater treatment plant (WWTP), which treats industrial wastewater from the zone of Porto Marghera (Venice, Italy) in an MBR, and in the Naviglio del Brenta River, which serves as a source of process water supply for this industrial zone. The focus of the study was placed on the comparison of levels of contamination of the WWTP effluent and the river water by selected PCBs in order to understand the major source of PCB pollution for the Lagoon of Venice and contrast them with the current legislation. Out of 45, 31 PCBs were detected in the WWTP at total median PCB concentration of 5.5 ng/L with a predominant presence of six indicator - PCBs (PCB 28, 52, 101, 138, 153 and 180), which accounted for 50-55% of total PCBs in both wastewater and sludge samples. The total PCB concentration was reduced by around 90% during the applied wastewater treatment to a median concentration of 0.5 ng/L at the WWTP effluent. In the samples collected from the river, 27 PCBs were detected at total median concentration of 2.1 ng/L, which is few times higher than the total PCB concentration found in the WWTP effluent. This result suggests that the current legislative limitations applied to the WWTPs effluent discharges into the Lagoon of Venice, regarding the presence of PCBs (i.e. absent) is rather arbitrary given the higher concentration levels encountered in river water than in the WWTP effluent of the studied industrial WWTP.

The fate of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in water from Poyang Lake, the largest freshwater lake in China

The fate of polycyclic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the water columns from Poyang Lake was studied. The total concentrations of OCPs and PAHs were 19.10-111.78 ng L(-1) and 5.56-266.1 ng L(-1), respectively. Among OCPs, endosulfans, chlordanes, and HCHs accounted for 21.96%, 24.6% and 24.65%, and were the predominant pollutants. Results suggested that the main sources of DDTs were residue from technical DDTs and dicofol, as well as antifouling paints for ships, while for HCHs, the main sources included long-distance transmission, agriculture activities and the combination of industrial products with separate lindane in use. As for PAHs, the predominance of lower molecular weight congeners demonstrated that petroleum and the combustion products of fuel oil, as well as other pyrogenic sources, contributed to the main input of PAHs in the Poyang region. The vehicle emissions were mostly from diesel engines. Moreover, HCH, DDT and BaP concentrations in water of Poyang Lake were all below the threshold values.