Occurrence and distribution of organochlorine pesticides - lindane, p,p'-DDT, and heptachlor epoxide - in surface water of China

Emerging and legacy contaminants on the Brazilian southern coast (Santa Catarina): A multi-biomarker approach in oysters Crassostrea gasar (Adanson, 1757)

Coastal environments, such as those in the Santa Catarina State (SC, Brazil), are considered the primary receptors of anthropogenic pollutants. In this study, our objective was to evaluate the levels of emerging contaminants (ECs) and persistent organic pollutants (POPs) in indigenous Crassostrea gasar oysters from different regions of SC coast in the summer season (March 2022). Field collections were conducted in the São Francisco do Sul, Itajaí, Florianópolis and Laguna coastal zones. We analyzed the bioaccumulation levels of 75 compounds, including antibiotics (AB), endocrine disruptors (ED), non-steroidal anti-inflammatory drugs (NSAIDs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Furthermore, we assessed biomarker responses related to biotransformation, antioxidant defense, heat shock protection and oxidative damage in oysters' gills. Prevalence of ECs was observed in the central and southern regions, while the highest concentrations of POPs were detected in the central-northern regions of SC. Oysters exhibited an induction in biotransformation systems (cyp2au1 and cyp356a1, sult and GST activity) and antioxidant enzymes activities (SOD, CAT and GPx). Higher susceptibility to lipid peroxidation was observed in the animals from Florianópolis compared to other regions. Correlation analyses indicated possible associations between contaminants and environmental variables in the biomarker responses, serving as a warning related to climate change. Our results highlight the influence of anthropogenic activities on SC, serving as baseline of ECs and POPs levels in the coastal areas of Santa Catarina, indicating more critical zones for extensive monitoring, aiming to conserve coastal regions.

A review of chloride ions removal from high chloride industrial wastewater: Sources, hazards, and mechanisms

To reduce metal pipe corrosion, improve product quality, and meet zero liquid discharge (ZLD) criteria, managing chloride ion concentrations in industrial wastewaters from metallurgical and chemical sectors has become increasingly important. This review provides detailed information on the sources, concentration levels, and deleterious effects of chloride ions in representative industrial wastewaters, and also summarizes and discusses various chloride ion removal techniques, including precipitation, ion exchange, physical separation, and advanced oxidation (AOPs). Among these, AOPs are particularly promising due to their ability to couple with other technologies and the diversity of their auxiliary technologies. The development of dechlorination electrode materials by electro-adsorption (CDI) can be inspired by the electrode materials used in chloride ion battery (CIB). This review also provides insights into exploring the effective combination of multiple chloride removal mechanisms, as well as the development of environmentally friendly composite materials. This review provides a theoretical basis and development direction for the effective treatment and secondary utilization of chlorine-containing industrial wastewater in the future.

Occurrence, spatiotemporal distribution patterns,partitioning and risk assessments of multiple pesticide residues in typical estuarine water environments in eastern China

The low terrain and the prosperous agriculture in the east of China, have caused the accumulation of pesticide residues in the estuaries. Therefore, this study analyzed the spatiotemporal distribution and partition tendency of 106 pesticides based on their abundance, frequencies, and concentrations in the aquatic environment of 16 river estuaries in 7 major basins in the eastern China by using solid-phase extraction (SPE) with high-performance liquid chromatography tandem mass spectrometry (HPLC‒MS/MS) and gas chromatography tandem mass spectrometry (GC‒MS/MS). In addition, potential risk of multiple pesticides was also evaluated. The results showed that herbicides were the dominant pesticide type, while triazines were the predominate substance group of pesticide. In addition, triadimenol, vinclozolin, diethylatrazine, prometryn, thiamethoxam, atrazine, and metalachlor were the major pesticides in the water, while prometryn, metalachlor, and atrazine were the main pesticides in the sediment. The average total concentration of pesticide was 751.15 ng/L in the dry season, 651.17 ng/L in the wet season, and 617.37 ng/L in the normal season, respectively. The estuaries of the Huai River Basin, the Yangtze River Basin, the Hai River Basin, and the Yellow River Basin have been affected by the low pollution treatment efficiency, weak infrastructure, and agricultural/non-agricultural activities in eastern China, resulting in relatively serious pesticide pollution. The estuaries of Huaihe River, Yangtze River, Xiaoqing River, and Luanhe River had large pesticide abundance and comparatively severe pesticide pollution, while the estuaries of Tuhai River and Haihe River had heavy pesticide contamination in the sediment, which might be induced by historical sedimentary factors. The log KOC values showed that except for thioketone, other pesticides were relatively stable due to the adsorption by sediment. The ecological risk assessment results indicated that insecticides had a high risk. Teenagers were the most severely affected by the noncarcinogenic risk of pesticides, while adults were mostly affected by the carcinogenic risk of pesticides. Therefore, pesticide hazards in the water environment of estuaries in eastern China needs to be further close supervision.

Land Use Influencing the Distribution of Pesticides in Surface Water: The Case of the Ma River and Its Tributaries in Thanh Hoa Province, Vietnam

Pesticide residues are regularly found in surface water, which could be dangerous for freshwater ecosystems and biodiversity. Pesticides may enter waters through a variety of pathways, but runoff from irrigation or precipitation has the highest quantities. Previous studies analyzing the pesticides pollution or ecological risks of pesticides focused on few regions (e.g., European and United States), whereas analysis of pesticide pollution in Southeast Asia and especially in Vietnam is limited. This study presents an investigation of banned pesticides used across the range of land use in catchments of the Ma river and its tributaries in Thanh Hoa province, Vietnam. Applying principal component analysis (PCA), we investigated the relationship between specific pesticides and land use. Besides, cluster analysis (CA), the method of aggregating monitoring locations, was applied in this study to find spatial pattern of pesticides pollution. Due to their persistence and remobilization during floods and runoff, all ten banned pesticides-eight insecticides (aldrin/dieldrin, BHC, chlordane, endrin, heptachlor, lindane, malathion, and parathion) and two herbicides (paraquat, and 2,4D)-still remain in surface water and are not presumably influenced by the fraction of land use area in the catchments. Clustering results revealed that banned pesticides still occur in some areas. Site TH08 close to Le Mon industrial zone and TH18 in Thanh Hoa city have higher concentrations of banned pesticides than other sites due to their highly toxic and long-time existence in the environment. Overall, our study provides approach to investigate pesticides in surface water for a province in Vietnam that may be used for future ecotoxicological studies to enhance risk assessment for stream ecosystems.

Organochlorine Compounds in the Amur (Heilong) River Basin (2000-2020): A Review

Persistent organic pollutants (POPs) are well-known contaminants that raise serious concerns, even more than 20 years after they were banned. Their worldwide distribution and persistence necessitate continuous monitoring in all components of the environment. The most challenging issues of POP regulation are associated with international water resources because their solutions require international cooperation in environment protection. This review provides data on various POPs (DDT, HCH, endrin, dieldrin, and PCBs) and their concentrations in aquatic organisms inhabiting the Amur River basin, one of the most poorly explored regions of Northeast Asia. Most studies have been conducted in the Songhua River (China), a tributary of the Amur River, which indicates that large inland bodies of water, especially those of international importance, require more extensive research.

Responses of signal crayfish Pacifastacus leniusculus to single short-term pulse exposure of pesticides at environmentally relevant concentrations

Although pesticides are often discharged into surface waters in pulses as opposed to a sustained release, the effect of episodic pollution events on freshwater crayfish is largely unknown. We monitored change in heart rate and distance moved to assess the response of signal crayfish Pacifastacus leniusculus to short-term exposure to environmentally relevant concentrations of metazachlor (MTZ), terbuthylazine (TER), and thiacloprid (TCL). Crayfish exposed to 20 µg/L of MTZ exhibited a significant increase in mean heart rate and distance moved. Increased heart rate was detected at 118 ± 74 s post-exposure to MTZ. There were no significant differences in mean heart rate and distance moved in crayfish exposed to 6 µg/L of TCL and 4 µg/L of TER. A significant correlation between heart rate and distance moved was found in all exposed groups. These results suggest that pulse exposure to MTZ impact crayfish physiology and behavior during short-term period. With pulse exposure to TCL and TER, crayfish not exhibiting a locomotor response may continue to be exposed to lower, but potentially harmful, levels of pollutants. Evidence of the impacts of pesticide pulse at environmentally relevant concentrations on crayfish is scarce. Further study is required to determine the ecological effects of such events on freshwater crayfish.

Coordinative Management of Soil Resources and Agricultural Farmland Environment for Food Security and Sustainable Development in China

Major problems in China's pursuit of sustainable agricultural development include inadequate, low-quality soil and water resources, imbalanced regional allocation and unreasonable utilization of resources. In some regions, overexploitation of soil resources and excessive use of chemicals triggered a web of unforeseen consequences, including insufficient use of agricultural resources, agricultural non-point source pollution and land degradation. In the past decade, China has changed its path of agricultural development from an output-oriented one to a modern, sustainable one with agricultural ecological civilization as its goal. First, the government has formulated and improved its laws and regulations on soil resources and the environment. Second, the government has conducted serious actions to ensure food safety and coordinated management of agricultural resources. Third, the government has planned to establish national agricultural high-tech industry demonstration zones based on regional features to strengthen the connection among the government, agri-businesses, scientific community and the farming community. As the next step, the government should improve the system for ecological and environmental regulation and set up a feasible eco-incentive mechanism. At the same time, the scientific community should strengthen the innovation of bottleneck technologies and the development of whole solutions for sustainable management in ecologically fragile regions. This will enhance the alignment between policy mechanisms and technology modes and effectively promote the sustainable development of agriculture in China.

Exposure patterns, chemical structural signatures, and health risks of pesticides in breast milk: A multicenter study in China

China is the world's largest pesticide user. These chemicals are bioaccumulative in the human body, and eventually could be transferred from the mother to the fetus/infant via placental and breastfeeding transport, which might pose developmental deficiency risks. In this study, human biomonitoring of legacy pesticides was conducted in three Chinese cities using 60 breast milk samples. The patterns, chemical structural signatures, and the estimated daily intake of pesticides were assessed. The median concentration of HCB (57.8 ng g^-1 lw, Interquartile range: 28.5-76.9 ng g^-1 lw) was the highest among all pesticides, whereas the HCHs, DDXs, TCVP, and heptachlor were also detected. A significantly different pattern of pesticides was found among three sampling cities: the Mianyang cases were mostly DDXs oriented while the Wuhan and Hangzhou cases were under HCB, HCHs, TCVP, and heptachlor influences. Maternal age and pre-pregnancy BMI were found to be the influencing factors for the pesticides in the breast milk, and dietary preferences were an important factor in the exposure scenario. Chemical structural signatures indicated that for HCHs and DDXs the exposure was mostly historical, while the lindane and dicofol exposure may exist among the volunteering mothers. The EF for chiral pesticides did not deviate significantly from the racemic value. The risk from breastfeeding was negligible according to the Chinese and UN standard, while some cases from Hangzhou and Wuhan exceeded the Canadian restrictions. Thus, the adverse health effects of chemical exposure by dietary intake for infants need to be closely monitored in future studies.

Degradation of highly chlorinated pesticide, lindane, in water using UV/persulfate: kinetics and mechanism, toxicity evaluation, and synergism by H2O2

Sulfate radical-advanced oxidation processes (SR-AOPs) are emerging technologies for decomposing organic pollutants in water. This study investigated the efficiency of UV/persulfate (UV/S₂O₈^2-) process to degrade lindane in water, showing 93.2% lindane removal ([lindane]₀ = 3.43 μM, [S₂O₈^2-]₀ = 100 μM) at a UV fluence of 720 mJ/cm². The lindane degradation followed first order kinetics and mechanistic studies suggested H-abstraction by SO₄^•- and Cl removal via C-Cl bond cleavage by UV-C light. Toxicity assessment using ECOSAR program showed toxicity gradually decreased and eventually no significant toxicity remained when all by-products vanished at high UV dose. Removal efficiency of lindane decreased from 93.2% to 38.4, 45.5, 56.0, 84.3 and 88.6%, by adding 1.0 mg/L humic acid or 1.0 mM CO₃^2-, HCO₃^-, Cl^- or SO₄^2-, respectively. Coupling of H₂O₂ with UV/S₂O₈^2- showed a significant synergistic effect with 99.0% lindane removal at a UV fluence of 600 mJ/cm², using [S₂O₈^2-]₀ = [H₂O₂]₀ = 50 μM while UV/H₂O₂ resulted in only 36.6% lindane removal ([lindane]₀ = 3.43 μM, [H₂O₂]₀ = 100 μM) at a UV fluence of 720 mJ/cm². The results indicate that SR-AOP has potential for consideration as a remedial technology to treat persistent chlorinated pesticides such as lindane in contaminated water.

Indoor persistent organic pollutants in agricultural areas from Argentina

Persistent Organic Pollutants (POPs) are anthropogenic chemicals extensively used in the past for industrial and agricultural purposes, characterized by their lipophilicity, ubiquity, volatility and environmental persistence. By other hand, chlorpyrifos is the most widely used current pesticide (CUPs) being the main insecticide used for crops in Argentina. The aim of this work was to assess levels of POPs and CUPs in different fractions of airborne particles collected indoor in agricultural areas from Argentina. Particles higher than 2.5 µm were trapped in polyurethane foams (PUF) while particles smaller than 1 µm and volatile compounds were adsorbed on activated charcoal. Compounds were analyzed by gas chromatograph with electron capture detector (GC-ECD). Endosulfans, chlordanes, PCBs, and HCHs were detected in all PUF samples, while endosulfans, chlorpyrifos, PCBs, and HCHs were the most abundant in smaller particles. Majority of pesticides showed higher concentrations during the summer season (1397.7 vs 832.5 pg/m³ ). Even adding up all measured organic compounds, no sample reaches the threshold limit value for indoor pesticides levels (0.1 pg/m³ ), neither in the large or small particle fraction. However, the fact that chronic exposure to POPs has been linked to several diseases raises concern for human health.

Potency of Phlebia species of white rot fungi for the aerobic degradation, transformation and mineralization of lindane

The widespread use of the organochlorine insecticide lindane in the world has caused serious environmental problems. The main purpose of this paper is to investigate the potency of several Phlebia species of white rot fungi to degrade, transform and mineralize lindane, and to provide the feasibility of using white rot fungi for bioremediation at contaminated sites. Based on tolerance experiment results, Phlebia brevispora and Phlebia lindtneri had the highest tolerance to lindane and were screened by degradation tests. After 25 days of incubation, P. brevispora and P. lindtneri degraded 87.2 and 73.3% of lindane in low nitrogen medium and 75.8 and 64.9% of lindane in high nitrogen medium, respectively. Several unreported hydroxylation metabolites, including monohydroxylated, dehydroxylated, and trihydroxylated products, were detected and identified by GC/MS as metabolites of lindane. More than 10% of [¹⁴C] lindane was mineralized to ¹⁴CO₂ by two fungi after 60 days of incubation, and the mineralization was slightly promoted by the addition of glucose. Additionally, the degradation of lindane and the formation of metabolites were efficiently inhibited by piperonyl butoxide, demonstrating that cytochrome P450 enzymes are involved in the fungal transformation of lindane. The present study showed that P. brevispora and P. lindtneri were efficient degraders of lindane; hence, they can be applied in the bioremediation process of lindane-contaminated sites.

Health risk assessment of heavy metals and pesticides: A case study in the main drinking water source in Dalian, China

Health risk associated with drinking water has attracted increasing attention worldwide. Here, we conducted a survey on the main drinking water sources of Dalian in China to clarify the local human health risk associated with heavy metal and pesticide contaminants in the drinking water sources. The results showed that six heavy metals, namely, copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), arsenic (As), and mercury (Hg), and two pesticides (atrazine and acetochlor) were detected in water samples, where the highest concentration of Hg (0.0621 μg L^-1) exceeded the domestic standard only. In addition to the above-mentioned metals, Cr was also detected in the sediment/soil samples. As to the pesticides, atrazine, acetochlor, hexachlorobenzene, p,p'-DDE, and p,p'-DDD were detected in the sediment/soil samples at ng g^-1 levels, and atrazine and acetochlor were found in water samples at ng L^-1 levels. The human health risk assessment showed no marked difference in carcinogenic and noncarcinogenic risks from drinking water. Our study approved that hexachlorobenzene and arsenic were the main contributors to human carcinogenic risks, which were calculated at the level of 10^-4. Furthermore, sediment and soil ingestion was considered as the major source of human health risk in our study area. This study revealed the current pollution status in the surrounding area of the drinking water source and the main source associated with human health risk, which established a sound basis for further decision-making to take necessary action on pollution control.

Distribution and sources of organic contaminants in surface sediments of Hooghly river estuary and Sundarban mangrove, eastern coast of India

This study investigated polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds such as polychlorinated biphenyls (PCBs) and DDT-related pesticides in surface sediments of Hooghly estuary and the Sundarban mangrove wetlands. Concentrations of ∑₁₇PAH, ∑₁₈₂PCB and ∑₆DDT ranged from 15.4 to 1731, not detected (nd) to 13.5 and nd to 8.97 ng g^-1 dry weight, respectively. Low levels of PCBs and low to moderate concentrations of DDTs and PAHs reflected recent development in West Bengal, which was dominated by agriculture and multifarious industries in the past. Diagnostic ratios suggested that major sources of PAHs are combustion processes, DDTs are input by agriculture, antifouling paints and public health campaigns, and organochlorines are predominantly from industrial origin. Heavier PCB congeners suggest local sources and short-range transport of such chemicals. Decision makers may use these findings for managing the Hooghly River watershed in order to promote a sustainable development on the eastern coast of India.

Semi-volatile organic compounds in tap water from Hangzhou, China: Influence of pipe material and implication for human exposure

Investigations on environmental behaviors of SVOCs have recently received great attention. However, the SVOC occurrence and influence of pipe materials on SVOC levels in the tap water have received little attention. Herein, we collected tap water samples from 25 households constructed at different ages in Hangzhou, China. Concentrations of 61 SVOCs, including phthalate esters (PAEs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs), were simultaneously determined in these collected samples. The potential human exposure risks were evaluated via the hazard index calculation. Our results showed that the total concentration of detected SVOCs (∑SVOCs) ranged from 110 to 289 μg/L (mean, 179 μg/L), and the SVOCs were dominated by PAHs (mean, 116 ng/L) and PAEs (mean, 55 ng/L) in Hangzhou tap water. 12 PCB congeners were detected in Hangzhou tap water samples, with hepta-CBs (68% of samples) as the most frequently detected PCBs. Nearly all tap water samples contained measurable o, p'-DDE, p, p'-DDT, and p, p'-DDD, and ∑DDTs had significantly (p < 0.05) higher concentrations than ∑HCHs. All target PAHs had high detection frequencies (>72%) in tap water samples, with their mean concentrations in the range of 2.1-41 ng/L. Tap water from steel pipes had relatively lower SVOC concentrations than that from either reinforced concrete, gray cast iron, or ductile iron pipes. Although no carcinogenic risks originating from exposure to SVOCs through ingestion and bathing were observed, the tap water from steel pipes showed relatively low exposure risks than that from other materials. Data provided here, for the first, are helpful in understanding the influence of pipe materials on human SVOC exposure risks through tap water intake.

Comparative analysis of freshwater species sensitivity distributions and ecotoxicity for priority pesticides: Implications for water quality criteria

Organochlorine pesticides (OCPs) and organophosphate pesticides (OPPs) posed severe threats to the aquatic environment in China. The toxicity data of 18 priority OCPs and OPPs for Chinese and American species were collected, and their species sensitivity distributions (SSDs) and ecotoxicity were compared. Physicochemical characteristics and chemical structures were used to analyze the difference in the pesticide toxicity. Results suggested that there is no significant difference between the HC₅ values (hazardous concentration protecting 95% of species) of China and America as a whole. However, the HC₅ values of nearly half of these pesticides (8/18) differ dramatically between Chinese and American due to the different resident species distribution. It indicated that it is necessary to develop local water quality criteria in China. The regression analysis of pesticides toxicity differences indicated a decrease in LC₅₀/EC₅₀ values (for Oncorhynchus mykiss and Carassius auratu) with the increase in molecular weights of pesticides. Pesticides with larger MWs might be more toxic to aquatic species. Similar trend was also observed in the regression analysis of a decrease in both American and Chinese HC₅ values for with increase of the number of containing halogen atoms. It indicated the potency of these parameters to be used to predict the ecotoxicity of pesticide.

Spatial distribution and source identification of hydrophobic organic compounds (HOCs) on sedimentary microplastic in Hong Kong

The spatial distribution, composition and source of hydrophobic organic compounds (HOCs) including polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs) of the sedimentary microplastics (0.25-5 mm) in Hong Kong were investigated. The concentration of ΣPAHs ranged between 70.8 and 1509 ng g^-1 with inter-site differences although the regional difference was insignificant, indicating localised pyrolytic and petrogenic input of PAHs. The concentration of ΣPCBs (13-1083 ng g^-1) varied with both study sites and regions with higher concentrations obtained in the western waters, possibly due to the input from Pearl River. Significantly higher concentrations of OCPs on eastern shores highlighted fishing and aquaculture activities in South China Sea a potential major source of OCPs. DDT and its metabolites (DDX, ranged from 1.96 to 626 ng g^-1) were the dominant forms of OCPs (45%-80%). Since most of the DDX existed as DDT, this suggested that there was a fresh input of DDT into the microplastics. As microplastics and HOCs cannot be removed effectively from the environment, reduction of potential ecotoxicological risks should rely on minimizing the use of plastics and HOCs.

Resource recovery from wastewater by anaerobic membrane bioreactors: Opportunities and challenges

This review examines the potential of anaerobic membrane bioreactor (AnMBR) to serve as the core technology for simultaneous recovery of clean water, energy, and nutrient from wastewater. The potential is significant as AnMBR treatment can remove a board range of trace organic contaminants relevant to water reuse, convert organics in wastewater to biogas for subsequent energy production, and liberate nutrients to soluble forms (e.g. ammonia and phosphorus) for subsequent recovery for fertilizer production. Yet, there remain several significant challenges to the further development of AnMBR. These challenges evolve around the dilute nature of municipal wastewater, which entails the need for pre-concentrating wastewater prior to AnMBR, and hence, issues related to salinity build-up, accumulation of substances, membrane fouling, and membrane stability. Strategies to address these challenges are proposed and discussed. A road map for further research is also provided to guide future AnMBR development toward resource recovery.

Polycyclic and organochlorine hydrocarbons in sediments of the northern South China Sea

We investigated the concentration distribution and composition of organic pollutants in sediments of the shelf and the deep northern South China Sea (NSCS). Concentrations of polycyclic aromatic hydrocarbons (Σ₁₅PAH; 10.69-66.45 ng g^-1), Dichlorodiphenyltrichloroethane (Σ₄DDT; 0-0.82 ng g^-1), and polychlorinated biphenyls (Σ₂₄PCB; 0-0.12 ng g^-1) are below established sediment quality guidelines, suggesting no environmental risk. Surprisingly, concentrations increase from the shelf to the deep NSCS, and are higher in the east of the study area. The organic pollutant composition indicates PAH mainly derived from pyrogenic sources, and mostly degraded DDT and PCB. However, in the deep NSCS, considerable contribution of petrogenic PAH, low chlorinated PCB and p,p'-DDT suggest more recent input from different sources compared to the shelf. From these results we infer that organic pollution in the NSCS does not originate from the Pearl River Estuary but from the NE SCS, SW of Taiwan.

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.

Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral ∑PFASs were within the range of 76-551pg/m³. Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral ∑PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral ∑PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition were simulated for neutral PFASs, and neutral ∑PFASs fluxes varied from 0.37 to 2.3pg/m²/s. In the dissolved phase of the surface water, concentrations of ionic ∑PFASs ranged from 1.6 to 118ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic ∑PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic ∑PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs.

Phytoremediation of organochlorine pesticides: Concept, method, and recent developments

Rapid increase in industrialization of world economy in the past century has resulted in significantly high emission of anthropogenic chemicals in the ecosystem. The organochlorine pesticides (OCPs) are a great risk to the global environment and endanger the human health due to their affinity for dispersion, transportation over long distances, and bioaccumulation in the food chain. Phytoremediation is a promising technology that aims to make use of plants and associated bacteria for the treatment of groundwater and soil polluted by these contaminants. Processes known to be involved in phytoremediation of OCPs include phytoaccumulation, rhizoremediation, and phytotransformation. Vegetation has been accounted to considerably amplify OCP elimination from soil, in contrast to non-planted soil, attributable to both, uptake within plant tissues and high microbial degradation of OCP within the root zone. Developing transgenic plants is a promising approach to enhance phytoremediation capabilities. Recent advances in the application of phytoremediation technique for OCPs, including uptake by plants and plant-microbe association in the rhizosphere for the enhanced degradation and mineralization of these pollutants, is presented in this review. Additionally, some attempts to improve this technique using transgenesis and role of certain enzymes are also discussed.

Anthropogenic organochlorine compounds as potential tracers for regional water masses: A case study of estuarine plume, coastal eddy, wind-driven upwelling and long-range warm current

Water masses are the crucial factor driving the terrigenous anthropogenic organochlorine compounds (OCs) migration from the coast to open sea. Therefore, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the Northern South China Sea (NSCS), where different types of water masses are generated by the East Asian summer monsoon: Pearl River estuary plume (PREP), Guangdong offshore eddy (GDEC), South China Sea warm current (SCSWC) and wind-driven upwelling current (WDUC). No discrepant distributions of OC concentrations were found in these water masses (p > 0.05). However, compositions and diagnostic ratios of HCHs, DDTs, trans- or cis-chlordane and PCBs could reflect the discrepancies in the input, transport and transformation of OCs caused by the hydrological characteristics of water masses, therefore, this allowing them to serve as potential tracers of regional water masses. In detail, α/γ-HCH and β-HCH percentages could indicate the weathered residue in the GDEC, long-range transport in the SCSWC, rapid photodegradation in the surface WDUC and biodegradation in the deep WDUC, respectively. The predominance of o, p'-DDT and p, p'-DDT could indicate fresh input in the PREP, GDEC and WDUC. DDT/DDTs of ratios <0.5 also reflected long-range transport in the SCSWC. Different DDD/DDE ratios indicated different oxygen environments of microbial degradation in the surface and deep water of the WDUC. Trans/cis-chlordane ratios could indicate the selective degradation of trans-chlordane in different water masses. Finally, a higher proportion of penta-PCB could reflect the strong paint additive sources carried by river erosion in the PREP.

Persistent organic pollutants in China's surface water systems

Following recent rapid industrialization, China is now one of the largest producers and consumers of organic chemicals in the world. This is compounded by variable regulatory oversight with respect to storage, use and waste management of these chemicals and their byproducts. This review synthesizes the data on the distribution of selected persistent organic pollutants (POPs) in waters in China. Surface water heavily polluted with POPs is distributed in the Yangtze River Estuary, Pearl River Delta, Minjiang River Estuary, Jiulongjiang Estuary, Daya Bay, Taihu Lake, and the waterways of Zhejiang Province, where concentrations of Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) frequently exceed both international and Chinese guideline values. These areas are mainly distributed along the southeast coast of China, within or downstream of major manufacturing districts, intensive agricultural basins, and other industrial centers. A comparison of the levels of OCPs in the aquatic environment of China with other indicative regions worldwide shows comparable levels of pollution (overall range from below detection limit (BDL) to 5104.8ng/L and regional means from 2.9-929.6ng/L). PAHs and PCBs pollution appear to be particularly serious in China (PAHs overall ranging from BDL to 474,000ng/L with regional means from 15.1-72,400ng/L; PCBs from BDL to 3161ng/L with regional means ranging from 0.2-985.2ng/L). There is as yet limited evidence of serious perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) pollution. We discuss major sources and processes responsible for high POP occurrence using a range of measures (including diagnostic ratios of different compounds), regulatory oversight and policy gaps in the control of POPs in China, and potential long-term health and ecological effects. We argue that water quality guidelines, pollution control measures and cleanup strategies for POPs in China should be urgently improved.

Polychlorinated biphenyls and organochlorine pesticides in River Brahmaputra from the outer Himalayan Range and River Hooghly emptying into the Bay of Bengal: Occurrence, sources and ecotoxicological risk assessment

River Brahmaputra (RB) from the outer Himalayan Range and River Hooghly (RH), a distributary of River Ganga, are the two largest transboundary perennial rivers supplying freshwater to the northeastern and eastern states of India. Given the history of extensive usage of organochlorine pesticides and increasing industrialization along the banks of these rivers we investigated selected organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the surface water of River Brahmaputra and River Hooghly. Geomean of ΣOCPs (53 ng L^-1) and Σ₁₉PCBs (108 ng L^-1) was higher in RH compared with geomean of ΣOCPs (24 ng L^-1) and Σ₁₉PCBs (77 ng L^-1) in RB. Among OCPs, γ-HCH showed maximum detection frequency in both the rivers reflecting ongoing lindane usage. DDT and endosulfan residues were observed at specific locations where past or ongoing sources exist. Elevated concentrations of heavier congeners (penta-hepta) were observed in those sites along RH where port and industrial activities were prevalent including informal electronic waste scrap processing units. Furthermore along River Hooghly PCB-126 was high in the suburban industrial belt of Howrah district. PCBs were found to be ubiquitously distributed in RB. Atmospheric transport of tri- and tetra-PCB congeners from the primary source regions might be a major contributor for PCBs in RB. Heavier congeners (penta-nona) in the urban centers of RB were likely due to industrial wastewater runoff from the oil refineries in the Brahmaputra valley. Σ₁₉PCBs concentrations in this study exceeded the USEPA recommended limit for freshwater. Ecotoxicological risk assessment showed the possibility of adverse impact on the organisms in the lower trophic level due to DDT and lindane contamination. Impact of endosulfan on fishes might be of considerable concern for aquatic environment.

Characteristics of residual organochlorine pesticides in soils under different land-use types on a coastal plain of the Yellow River Delta

The residual levels of organochlorine pesticides (OCPs) were examined in soils covering five types of land use along a salinity gradient on the Yellow River Delta. The most prominent OCPs were dichlorodiphenyltrichloroethane (∑DDT, arithmetic mean = 5.11 μg kg(-1)), hexachlorocyclohexane (∑HCH, 1.69 μg kg(-1)) and ∑endosulfan (10.4 μg kg(-1)). The spatial variability of OCPs composition shifted from γ-HCH and o,p'-DDT dominated pesticides in coastal soils to p,p'-DDE dominated pesticides in inland soils. In different land-use types, the percentages of β-HCH and p,p'-DDE are characterized by more recalcitrant components in decreasing order of vegetable fields, cereal fields, cotton fields, wetlands and tidal flats with increasing soil salinity. However, the less recalcitrant components, γ-HCH and o,p'-DDT, showed an opposite trend. Endosulfan sulfate predominated in all land-use types. Residual levels of β-HCH were affected by soil organic matter. The correlations between γ-HCH and clay content and between p,p'-DDE, o,p'-DDT and salinity might associate with the influence of sediment cotransport by the Yellow River and the density of anthropogenic activities in coastal region. Depth distribution of the OCPs in typical soil profiles also implied that local historical usage and sediment transport by the Yellow River both affected the OCPs residual in this region.

Temporal-spatial loss of diffuse pesticide and potential risks for water quality in China

Increasing amount of pesticide has been used in Chinese agricultural system with effects on environmental quality and human health. The comprehensive inventory of pesticide use in six main crop categories over the period from 1990 to 2011 in China was conducted. The national average pesticide use intensity was estimated 1.74k g · ha(-1) for grain crops in paddy land, 1.31 kg · ha(-1) for grain crops in dry land, 1.38 kg · ha(-1) for economic crops, 3.82 kg · ha(-1) for vegetables, 1.54 kg · ha(-1) for tea plantations, and 3.49 kg · ha(-1) for orchards. The pesticide use was estimated to be approximately 5.24 × 10(4)t for grain crops in paddy land, 1.05 × 10(5)t for grain crops in dry land, 3.08 × 10(4)t for economic crops, 7.51 × 10(4)t for vegetables, 3.26 × 10(3)t for tea plantations, and 4.13 × 10(4)t for orchards. Based on the pesticide use and loss coefficients for each category, the distribution of pesticide loss in China was calculated. Total pesticide loss in China was estimated about 4.39 × 10(3)t in 2011. The pesticide loss from six main crop categories was about 14.84% for grain crops in paddy land of total pesticide loss, 33.31% for grain crops in dry land, 10.47% for economic crops, 26.37% for vegetables, 1.08% for tea plantations and 13.93% for orchards. The results indicated that the highest pesticide use intensity and highest pesticide loss rate occurred in China's eastern and central provinces. The Monte Carlo simulation was used to quantify the uncertainties associated with estimation of pesticide use and loss rate for the six types of crops. The potential risk to national water quality was assessed and the water in the provinces of Henan, Shandong, Hebei, Beijing and Shanghai was at high risk for pesticide pollution. The implication for the future agricultural and environmental policies on reducing the risk to environmental quality was also summarized.

Organic pollutants in the central and coastal Beibu Gulf, South China Sea

Surface sediments from the central and coastal Beibu Gulf, southern China, were analyzed for persistent organic pollutants. The absence of polychlorinated biphenyls (PCB; generally below detection limit), low concentrations of polycyclic aromatic hydrocarbons (PAH; 24-647 ng g(-1)), and locally high contamination with organo-chloro pesticides (DDT; 0.03-92 ng g(-1)) reflect the early stages of development in southwest China, with human activities dominated by agriculture and low impact of industry. Concentrations of PCB and PAH indicate no ecological risk, while DDT accumulation poses a probable toxic risk in coastal but not in shelf sediments. Diagnostic ratios suggest PAH originating mainly from combustion of biomass and diesel fuels, and recent DDT use in agriculture and antifouling paint. Distribution patterns along the coastal-shelf-gradient indicate mainly airborne transport of PAH and waterborne transport of DDT. In the central Gulf, also water column samples reveal low concentrations of PAH (1.7-7.8 ng L(-1)) and DDT (0.006-0.053 ng L(-1)).

Spatial distribution, source apportionment and ecological risk assessment of residual organochlorine pesticides (OCPs) in the Himalayas

The Indian Himalayan Region (IHR) is one of the important mountain ecosystems among the global mountain system which support wide variety of flora, fauna, human communities and cultural diversities. Surface soil samples collected from IHR were analysed for 23 organochlorine pesticides (OCPs). The concentration of ∑OCPs ranged from 0.28 to 2143.96 ng/g (mean 221.54 ng/g) and was mostly dominated by DDTs. The concentration of ∑DDTs ranged from 0.28 to 2126.94 ng/g (mean 216.65 ng/g). Other OCPs such as HCHs, endosulfan and heptachlor, Aldrin and dieldrin were detected in lower concentration in IHR. Their concentrations in soil samples ranged from ND to 2.79 ng/g for HCHs, ND to 2.83 ng/g for endosulfans, NDto 1.46 ng/g for heptachlor, ND to 2.12 ng/g for Aldrin and ND to 1.81 ng/g for dieldrin. Spatial distribution of OCPs suggested prevalence of DDTs and HCHs at Guwahati and Itanagar, respectively. The close relationship between total organic carbon (TOC) and part of OCP compounds (especially α- and γ-HCH) indicated the important role of TOC in accumulation, binding and persistence of OCP in soil. Diagnostic ratio of DDT metabolites and HCH isomers showed DDT contamination is due to recent application of technical DDT and dicofol, and HCH contamination was due to mixture of technical HCH and lindane source. This was further confirmed by principal component analysis. Ecological risk analysis of OCP residues in soil samples concluded the moderate to severe contamination of soil.

Pesticide levels and environmental risk in aquatic environments in China--A review

China is one of the largest producers and consumers of pesticides in the world today. Along with the widespread use of pesticides and industrialization, there is a growing concern for water quality. The present review aims to provide an overview of studies on pesticides in aquatic environments in China. The levels in the water, sediment and biota were scored according to a detailed environmental classification system based on ecotoxicological effect, which is therefore a useful tool for assessing the risk these compounds pose to the aquatic ecosystem. Our review reveals that the most studied areas in China are the most populated and the most developed economically and that the most frequently studied pesticides are DDT and HCH. We show maps of where studies have been conducted and show the ecotoxicological risk the pesticides pose in each of the matrices. Our review pinpoints the need for biota samples to assess the risk. A large fraction of the results from the studies are given an environmental classification of "very bad" based on levels in biota. In general, the risk is higher for DDT than HCH. A few food web studies have also been conducted, and we encourage further study of this important information from this region. The review reveals that many of the most important agricultural provinces (e.g., Henan, Hubei and Hunan) with the largest pesticide use have been the subject of few studies on the environmental levels of pesticides. We consider this to be a major knowledge gap for understanding the status of pesticide contamination and related risk in China. Furthermore, there is also a lack of studies in remote Chinese environments, which is also an important knowledge gap. The compounds analyzed and reported in the studies represent a serious bias because a great deal of attention is given to DDT and HCH, whereas the organophosphate insecticides dominating current use are less frequently investigated. For the future, we point to the need for an organized monitoring plan designed according to the knowledge gaps in terms of geographical distribution, compounds included, and risks.

Air-Seawater Exchange of Organochlorine Pesticides along the Sediment Plume of a Large Contaminated River

Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources.

Spirodela polyrhiza stimulates the growth of its endophytes but differentially increases their fenpropathrin-degradation capabilities

In situ remediation of organic contaminants via physical, chemical, and biological approaches is a practical technique for cleansing contaminated water and soil. In the present study, we showed that the three bacterial strains Pseudomonas sp. E1, Klebsiella terrigena E42, and Pseudomonas sp. E46, which can infect and colonize the aquatic plant Spirodela polyrhiza, utilize fenpropathrin as the sole carbon source for growth. S. polyrhiza helped enhance fenpropathrin degradation by E46 by 17.5%, only slightly improved fenpropathrin degradation by E42, and had no effect on strain E1. The application of plant exudates and extracts from fenpropathrin-unexposed/induced plants stimulated bacterial growth of the three strains, but resulted in differential fenpropathrin degradation, suggesting that not all plants and their endophytic bacteria are suitable for coupling phytoremediation and microbial-remediation. Moreover, addition of soil sediments to a microcosm not only stimulated the growth of strain E46 but also increased the rate of fenpropathrin degradation.

Biodegradation of heptachlor and heptachlor epoxide-contaminated soils by white-rot fungal inocula

The ability of certain white-rot fungi (WRF) inocula to transform heptachlor and heptachlor epoxide and its application in artificially contaminated soil were investigated. Fungal inoculum of Pleurotus ostreatus eliminated approximately 89 % of heptachlor after 28 days of incubation, and chlordene was detected as the primary metabolite. The fungal inoculum of Pleurotus ostreatus had the highest ability to degrade heptachlor epoxide; approximately 32 % were degraded after 28 days of incubation, and heptachlor diol was detected as the metabolite product. Because Pleurotus ostreatus transformed heptachlor into a less toxic metabolite and could also effectively degrade heptachlor epoxide, it was then selected to be applied to artificially contaminated soil. The spent mushroom waste (SMW) of Pleurotus ostreatus degraded heptachlor and heptachlor epoxide by approximately 91 and 26 %, respectively, over 28 days. This finding indicated that Pleurotus ostreatus SMW could be used to bioremediate heptachlor- and heptachlor epoxide-contaminated environments.

Remediation of organochlorine pesticides (OCPs) contaminated site by successive methyl-β-cyclodextrin (MCD) and sunflower oil enhanced soil washing - Portulaca oleracea L. cultivation

An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs)-contaminated site. Elevated temperature (50 °C) combined with ultrasonication (35 kHz, 30 min) at 25 g L(-1) methyl-β-cyclodextrin and 100 mL L(-1) sunflower oil were effective in extracting OCPs from the soil. After four successive washing cycles, the removal efficiency for total OCPs, DDTs, endosulfans, 1,2,3,4,5,6-hexachlorocyclohexanes, heptachlors, and chlordanes were all about 99%. The 4th washed soil with 3 months cultivation of Portulaca oleracea L. and nutrient addition significantly increase (p<0.05) the number, biomass carbon, nitrogen, and functioning diversity of soil microorganisms. This implied that the microbiological functioning of the soil was at least partially restored. This combined cleanup strategy proved to be effective and environmental friendly.

Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments

The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO3) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1%, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p < 0.05) evaluated by Tenax TA extraction and a three-compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and nitrogen, ATP production, denitrifying bacteria count, and nitrate reductase activity. Such similar trend between OCP biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.

Residues and enantiomeric profiling of organochlorine pesticides in sediments from Xinghua Bay, southern East China Sea

The spatial distribution and chiral signatures of organochlorine pesticides (OCPs) in the surface sediments of Xinghua Bay, southern East China Sea, were investigated. The total OCP concentrations ranged from 9.15 to 40.5 ng/g dry weight, with a predominance of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs). The isomer ratios of α-HCH/γ-HCH (less than 1.0) and the predominant β-HCH implied that HCH residues were derived not only from historical technical HCH use but also from the additional use of lindane in this area. The isomer ratios of p,p'-DDT/(p,p'-DDD + p,p'-DDE) and o,p'-DDT/p,p''-DDT, and a strong correlation (R = 0.83, P < 0.001) between p,p'-DDE and o,p'-DDT depicted a cocktail input pattern of dicofol-type DDT and technical DDT. Moreover, the fact that only cis-chlordane was detectable for all sampling stations suggested the past application of technical chlordane. Based on the sediment quality guidelines (SQG), γ-HCH is the main OCP species of ecotoxicological concern in Xinghua Bay. Enantiomeric analysis showed that the (+)-enantiomers of α-HCH and o,p'-DDT were more prevalent than the (-)-enantiomers in most samples, whereas both racemic and nonracemic residues existed for o,p'-DDD. These results implied that the SQG of chiral OCPs should be reassessed using concentrations of their individual enantiomers.

Assessing cancer risk in China from γ-hexachlorocyclohexane emitted from Chinese and Indian sources

Three models, including an atmospheric transport model, a multimedia exposure model, and a risk assessment model, were used to assess cancer risk in China caused by γ-HCH (gamma-hexachlorocyclohexane) emitted from Chinese and Indian sources. Extensive model investigations revealed the contribution of different sources to the cancer risk in China. Cancer risk in Eastern China was primarily attributable to γ-HCH contamination from Chinese sources, whereas cancer risk in Western China was caused mostly by Indian emissions. The contribution of fresh use of lindane in India to the cancer risk in China was almost 1 order of magnitude higher than that of the reemission of γ-HCH from Indian soils. Of total population, 58% (about 0.79 billion) residents in China were found to live in the environment with high levels of cancer risk exceeding the acceptable cancer risk of 10(-6), recommended by the United States Environmental Protection Agency (U.S. EPA). The cancer risk in China was mostly induced by the local contamination of γ-HCH emitted from Chinese sources, whereas fresh use of lindane in India will become a significant source of the cancer risk in China if Indian emissions maintain their current levels.

Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China

The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p'-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a (63)Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29 ± 0.69 ng L(-1) and 423.13 ± 577.85 ng g(-1) dry wt., respectively. In the spring of 2005, the total DDXs were 0.36 ± 0.91 ng L(-1) for water and 35.93 ± 62.65 ng g(-1) dry wt. for SPM. The average concentration of DDXs for sediments was 7.10 ± 7.57 ng g(-1) dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29-36 % of the sites for water and 55-61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63 × 10(-3) to 2.27 × 10(-4), with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90-2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines.

Organophosphorus and carbamate pesticide residues detected in water samples collected from paddy and vegetable fields of the Savar and Dhamrai Upazilas in Bangladesh

Several types of organophosphorous and carbamate pesticides have been used extensively by the farmers in Bangladesh during the last few decades. Twenty seven water samples collected from both paddy and vegetable fields in the Savar and Dhamrai Upazilas in Bangladesh were analyzed to determine the occurrence and distribution of organo-phosphorus (chlorpyrifos, malathion and diazinon) and carbamate (carbaryl and carbofuran) pesticide residues. A high performance liquid chromatograph instrument equipped with a photodiode array detector was used to determine the concentrations of these pesticide residues. Diazinon and carbofuran were detected in water samples collected from Savar Upazila at 0.9 μg/L and 198.7 μg/L, respectively. Malathion was also detected in a single water sample at 105.2 μg/L from Dhamrai Upazila. Carbaryl was the most common pesticide detected in Dhamrai Upazila at 14.1 and 18.1 μg/L, while another water sample from Dhamrai Upazila was contaminated with carbofuran at 105.2 μg/L. Chlorpyrifos was not detected in any sample. Overall, the pesticide residues detected were well above the maximum acceptable levels of total and individual pesticide contamination, at 0.5 and 0.1 μg/L, respectively, in water samples recommended by the European Economic Community (Directive 98/83/EC). The presence of these pesticide residues may be attributed by their intense use by the farmers living in these areas. Proper handling of these pesticides should be ensured to avoid direct or indirect exposure to these pesticides.

Thyroid hormone disrupting activities associated with phthalate esters in water sources from Yangtze River Delta

Thyroid hormone disrupting compounds in water sources is a concern. Thyroid hormone (TH) agonist and antagonist activities of water sources from the Yangtze River, Huaihe River, Taihu Lake and ground water in the Yangtze River Delta region were evaluated by use of a TH reporter gene assay based on the green monkey kidney fibroblast (CV-1). While weak TH receptor (TR) agonist potency was observed in only one of 15 water sources, antagonist potency was present in most of the water sources. TR antagonist equivalents could be explained by the presence of dibutyl phthalate (DBP), with concentrations ranging from 2.8×10(1) to 1.6×10(3) μg DBP /L (ATR-EQ(50)s). None of the ground waters exhibited TH agonist potencies while all of the samples from Taihu Lake displayed notable TR antagonist potencies. To identify the responsible thyroid active compounds, instrumental analysis was conducted to measure a list of potential thyroid-disrupting chemicals, including organochlorine (OC) pesticides and phthalate esters. Combining the results of the instrumental analysis with those of the bioassay, DBP was determined to account for 17% to 144% of ATR-EQ(50)s in water sources. Furthermore, ATR-EQ(20-80) ranges for TR antagonist activities indicated that samples from locations WX-1 and WX-2 posed the greatest health concern and the associated uncertainty may warrant further investigation.

Agricultural non-point source pollution in China: causes and mitigation measures

Non-point source (NPS) pollution has been increasingly serious in China since the 1990s. The increases of agricultural NPS pollution in China is evaluated for the period 2000-2008 by surveying the literature on water and soil pollution from fertilizers and pesticides, and assessing the surplus nitrogen balance within provinces. The main causes for NPS pollution were excessive inputs of nitrogen fertilizer and pesticides, which were partly the result of the inadequate agricultural extension services and the rapid expansion of intensive livestock production with little of waste management. The annual application of synthetic nitrogen fertilizers and pesticides in China increased by 50.7 and 119.7%, respectively, during 1991-2008. The mitigation measures to reduce NPS pollution include: correct distortion in fertilizer prices; improve incentives for the recycling of organic manure; provide farmers with better information on the sound use of agro-chemicals; and tighten the regulations and national standards on organic waste disposal and pesticides use.

Organochlorine pesticides in sediments of Laizhou Bay and its adjacent rivers, North China

Organochlorine pesticides (HCHs, DDTs and HCB) have been investigated in sediments of Laizhou Bay and its adjacent rivers. The average concentrations of HCHs, DDTs and HCBs are 0.09ng/gdw, 0.59 and 0.05 for marine sediments and 0.55, 8.6 and 1.1 for riverine sediments, respectively. Laizhou Bay is less contaminated by HCHs and DDTs in comparison with other coastal regions around the world, including the other two biggest bays in Bohai Sea. Fresh input of lindane and dicofol-type DDT were found in several riverine sites. Relatively strong TOC-dependence of HCB distribution in the entire studied area suggested no point source existed and/or water-sediment equilibrium achieved. No significant difference of α/γ-HCH ratios have been observed between marine and riverine sediments. However, o,p'-DDT/p,p'-DDT ratios varied largely between the two regions.

Modeling contaminant concentration distributions in China's centralized source waters

Characterizing contaminant occurrences in China's centralized source waters can provide an understanding of source water quality for stakeholders. The single-factor (i.e., worst contaminant) water-quality assessment method, commonly used in Chinese official analysis and publications, provides a qualitative summary of the country's water-quality status but does not specify the extent and degree of specific contaminant occurrences at the national level. Such information is needed for developing scientifically sound management strategies. This article presents a Bayesian hierarchical modeling approach for estimating contaminant concentration distributions in China's centralized source waters using arsenic and fluoride as examples. The data used are from the most recent national census of centralized source waters in 2006. The article uses three commonly used source water stratification methods to establish alternative hierarchical structures reflecting alternative model assumptions as well as competing management needs in characterizing pollutant occurrences. The results indicate that the probability of arsenic exceeding the standard of 0.05 mg/L is about 0.96-1.68% and the probability of fluoride exceeding 1 mg/L is about 9.56-9.96% nationally, both with strong spatial patterns. The article also discusses the use of the Bayesian approach for establishing a source water-quality information management system as well as other applications of our methods.

Identification of trace organic pollutants in freshwater sources in Eastern China and estimation of their associated human health risks

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in ten water samples (four pairs of tap water with source water and two additional tap water) were analyzed and a US EPA algorithm was used to estimate their associated human health risks. Organochlorine pesticides were found in most samples analyzed. Concentrations of total PAHs ranged from 4.8 to 84.4 and 0.7 to 53.8 ng/l, for source and tap water, respectively. Carcinogenic and noncarcinogenic risk assessments were employed for various trace organic pollutants in the tap water. The results indicated that carcinogenic risk for male and female lifetime of tap water from XuZh (XZ) city was higher than the others. XZ located in the northern part of Jiangsu province, which takes ground water as the water source. Children were more vulnerable to the carcinogenic chemicals than adults. Carcinogenic risks for male children (0-14 years old) in XZ were the highest, reaching 3.68 × 10(-6). Contribution analysis showed that dibenz[a,h]anthracene contributed most to the carcinogenic risk in XZ city, and α-HCH, β-HCH and γ-HCH posed the most carcinogenic risk in tap water from GoHu (GH) in Eastern Taihu Lake. Additionally, noncarcinogenic risks posed by the detected chemicals to local people were negligible. Risk alleviation strategies should be adopted, taking into account the results of these health risk assessments.

Regulation of iodothyronine deiodinases and sodium iodide symporter mRNA expression by perchlorate in larvae and adult Chinese rare minnow (Gobiocypris rarus)

Perchlorate is a widespread contaminant in the aquatic environment. In the present work, the expressions of deiodinase enzymes (d1, d2, and d3) and sodium iodide symporter (nis) genes were determined after larval and adult rare minnow (Gobiocypris rarus) exposed to 5 and 50 μg/L perchlorate for 21 days. The results showed that deflation of swim bladder development was observed in larvae at 50 μg/L perchlorate treatment. An up-regulation of the d2 and nis mRNA levels were observed in the larve and in brain of adults. Meanwhile the expressions of d3 mRNA levels were significantly down-regulated in the liver. These results indicate the changes in d2, nis, and d3 mRNA expression brings about increased outer-ring deiodination, idodine uptake, and a further decrease of inner-ring deiodination, respectively reflecting auto-regulation of hypothalamic-pituitary-thyroid (HPT) axis in adult after perchlorate exposure. The larval fish development could be affected by perchlorate at environmentally relevant concentrations.

Metabolism of organochlorine pesticide heptachlor and its metabolite heptachlor epoxide by white rot fungi, belonging to genus Phlebia

White rot fungi of the genus Phlebia have demonstrated a high capacity to degrade organic pollutants, including polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls. In this study, we evaluated the ability of 18 white rot fungi species of genus Phlebia to degrade heptachlor and heptachlor epoxide, and described the metabolic pathways by selected white rot fungi. Phlebia tremellosa, Phlebia brevispora and Phlebia acanthocystis removed about 71%, 74% and 90% of heptachlor, respectively, after 14 days of incubation. A large amount of heptachlor epoxide and a small amount of 1-hydroxychlordene and 1-hydroxy-2,3-epoxychlordene were detected as metabolic products of heptachlor from most fungal cultures. The screening of heptachlor epoxide-degrading fungi revealed that several fungi are capable of degrading heptachlor epoxide, which is a recalcitrant metabolite of heptachlor. Phlebia acanthocystis, P. brevispora, Phlebia lindtneri and Phlebia aurea removed about 16%, 16%, 22% and 25% of heptachlor epoxide, respectively, after 14 days of incubation. Heptachlor diol and 1-hydroxy-2,3-epoxychlordene were produced in these fungal cultures as metabolites, suggesting that the hydrolysis and hydroxylation reaction occur in the epoxide ring and in position 1 of heptachlor epoxide, respectively.

Enrichment of chlorobenzene and o-nitrochlorobenzene on biomimetic adsorbent prepared by poly-3-hydroxybutyrate (PHB)

Poly-3-hydroxybutyrate (PHB) was used as a new material to prepare a biomimetic adsorbent by a modified double emulsion solvent evaporation technique. The enrichment capacities of the adsorbent for the toxic liposoluble organic compounds were evaluated by chlorobenzene (CB) and o-nitrochlorobenzene (o-NCB) with the adsorption isotherms, enrichment factor (EF) and enrichment kinetics. The results showed that Sips isotherm fitted the experimental data better than Langmuir and Freundlich models, as well as the pseudo-second order kinetic model fitted better than the first order model. For CB and o-NCB, the maximum adsorption capacity was 125.99 and 39.56 m gg(-1), while the maximum EF was 1204 and 1149 at 20 degrees C for 36h, though the specific surface area (BET) of the adsorbent was only 8.45 m(2)g(-1). CB had a higher EF than o-NCB because the hydrophilic group (-NO(2)) decreases the liposoluble ability of o-NCB. K(ow) has a positive correlation with EF, so the organochlorine compounds are liable to be adsorbed by the adsorbent. The results indicated that PHB, even polyhydroxyalkanoates, can be a new biodegradable adsorption material.