Organochlorine Pesticides In Surface Water Research Articles

Study on the Aral Sea crisis from the risk assessment of polycyclic aromatic hydrocarbons and organochlorine pesticides in surface water of Amu Darya river basin in Uzbekistan

The Amu Darya River, as one of the important flows of the Aral Sea located in the semi-arid area of Central Asia, also performed as the primary water supply for Uzbekistan. Therefore, the residues and risks of anthropogenic-related persistent organic pollutants (POPs) in waters of the Amu Darya River were conducted in the present study to elucidate their possible effects on the water safety in such a specific area as well as on the Aral Sea Crisis from a new perspective. Thirty-nine water samples distributed along the Amu Darya River to the coastal of the Aral Sea were analyzed for both polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) occurrence, showing the total concentrations of ΣOCPs and ΣPAHs in the range of 1.16–22.75 ng/L and 3.18–506.26 ng/L, respectively. Spatial differences showed higher levels for both OCPs and PAHs along the lower reaches of the Amu Darya River due to intense human activities. Source identification performed by isomer ratios indicated that dichlorodiphenyltrichloroethanes (DDTs) probably originated from recent use, while hexachlorocyclohexanes (HCHs), chlordanes, and endosulfans originated mainly from historical usage. Furthermore, the principal component analysis showed PAHs were from coal and petroleum combustion (65.2%), biomass combustion (27.2%), and industrial chemical combustion (7.64%). The human health risk assessment demonstrated no carcinogenic or non-carcinogenic risks at present. However, moderate to high ecological risks to aquatic organisms especially were observed along the lower reaches, especially the delta area. The results obtained would not only provide important basic data for such a semi-arid area but also show us the possible toxic effects induced by such pollutants, which should attract more attention in the shrinking case of the Aral Sea.

Sediment-water partitioning and risk assessment of organochlorine pesticides along the urban, peri-urban and rural transects of Krishna River Basin, Peninsular India

Organochlorine pesticides (OCPs) were widely used in the past for pest control in agricultural lands and vector control programs in India. Due to their persistence and toxic impacts, we have quantified twenty OCPs in surface water, groundwater, and surface sediment samples along the Krishna River Basin (KRB), flowing through Peninsular India. Samples were collected along the urban, peri-urban, and rural transects of the KRB to understand the relation between the occurrence of pesticidal organochlorine pollutants based on the land use and land cover (LULC) and asses potential risk. Diagnostic ratios revealed ongoing Lindane usage in rural and peri-urban transects. On the contrary, the urban transect of the Musi River (MR) showed fresh inputs of technical HCH. The ratios of (p,p'-DDE+ p,p'-DDD)/ΣDDT >0.5 and α/β-Endosulfan < 2.33 for most of the sites across the three transects for surface water, groundwater, and sediment indicate past DDT and Endosulfan usage across KRB. Excluding p,p'-DDE, and heptachlor in most of the sites, the logKOC' was higher than logKOC for other OCPs in the urban transect. However, for all the OCPs, the logKOC' was lower than logKOC in the peri-urban and rural transects of KRB thereby indicating that riverine sediment is acting as a sink for OCPs. The Krishna River annually transport about 0.24 tons HCH, 0.11 tons of DDT and 0.1 tons of Endosulfan. Despite having low water discharge, the compound-specific fluxes of the Wyra river are higher than the other two tributaries. Ecotoxicological risk assessment based on the Hazard Quotient suggested DDT pose higher risks to scud (zooplankton) and dinoflagellate and diatom (phytoplankton) whereas Endosulfan poses a threat to Bluegill (fish).

Spatio-temporal variations and ecological risks of organochlorine pesticides in surface waters of a plateau lake in China.

Qilu Lake is one of the 9 plateau lakes in Yunnan, China, with a lake surface altitude of 1796.62m above sea level. In spite of the importance and agriculturally-intensive phenomenon in Qilu Lake Basin, few studies have provided a modern evaluation of pesticide residues and potential effects to local aquatic organisms. The primary goal of this study was to determine the spatio-temporal variations of organochlorine pesticides (OCPs) in this area, and to further assess the related ecological risks. Of the 25 OCPs analyzed, 14 were detected, and the concentrations of ∑25OCPs were highest in the upstream of rivers, followed by regions close to the lake shore, and the lowest concentrations were found in Qilu Lake in every season except winter. The concentrations of ∑25OCPs were the highest in summer, and the lowest in winter. OCP concentrations in spring and in autumn were similar. 4,4'-DDD, γ-HCH, HCB, trans-chlordane, and cis-chlordane were 5 OCPs with relatively high risk in Qilu Lake Basin. Interestingly, higher OCP concentrations do not necessarily correspond to higher ecological risk levels. Low predicted no-effect concentration (PNEC) values and relatively high toxicity of these OCPs led to their high risk quotient (RQ) values. This work further illustrated that although OCPs have been banned for many years, they were still frequently detected in surface waters, and caused risks to aquatic animals.

Application of the NU-1000 coated SPME fiber on analysis of trace organochlorine pesticides in water

Herein, a novel solid-phase microextraction (SPME) fiber based on the NU-1000 sorbent was developed for direct immersion extraction of organochlorine pesticides (OCPs) in water samples. As a kind of metal-organic framework, the NU-1000 possessed the mesoporous channels which were beneficial for the mass transfer of target analytes. Extraction equilibrium was achieved rapidly with the optimal extraction time of 30 min. The NU-1000 coated fiber with a high specific surface area showed better extraction efficiencies than commercial fibers (65 μm PDMS/DVB or 85 μm PA) towards OCPs, with the enrichment factors of the NU-1000 coated fiber 2–20 times higher than the latter. NU-1000 coated fiber showed higher extraction efficiencies toward polycyclic aromatic hydrocarbons (PAHs) than OCPs and nitrobenzenes. This indicated that π-π interaction and CH-π interaction between pollutants and aromatic groups of the NU-1000 contributed to the high extraction efficiencies. Under the optimal conditions (extraction at 40 °C for 30 min and desorption at 260 °C for 6 min), the NU-1000 coated fiber coupled with gas chromatography-mass spectrometry (GC-MS) exhibited satisfied analytical performance on analysis of OCPs, with a wide linear range (0.1–2000 ng L−1), low limits of detections (LODs, 0.011–0.058 ng L−1), and good reproducibility and repeatability. The established method has been successfully applied to the determination of OCPs in surface water with good sensitivity and recoveries, which proved the great promise of the NU-1000 on the extraction of organic pollutants with conjugated groups.

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.

Assessment of currently used organochlorine pesticides in surface water and sediments in Xiangjiang river, a drinking water source in China: Occurrence and distribution characteristics under flood events

Xiangjiang (XJ) is a typical urban inland river that serves as a drinking water source, which may be affected by the currently used organochlorine pesticides (CUOCPs) originating from agricultural activities in the vicinity. On this basis, this study comprehensively explored the occurrence and distribution characteristics of CUOCPs in surface water and sediments under long-term precipitation and subsequent floods. Considering the low concentration of CUOCPs in water, a technique combining high-throughput organic analysis with high-volume solid phase extraction (High-throat/Hi-volume SPE) was introduced for effective analysis of CUCOPs. The results showed that the concentration of CUOCPs in the water and sediments of XJ ranged from 2.33 to 6.40 ng L−1 (average of 3.93 ± 1.15 ng L−1) and from 1.52 to 21.2 ng g−1 (average of 6.60 ± 4.31 ng g−1 dw), respectively. The distribution of CUOCPs in water was consistent throughout XJ, but that in sediments was not uniform, indicating a stronger impact of floods on water than on sediments. Water-sediment partition coefficients were generally >2 L g−1, showing a tendency of CUOCP dominance in sediments. The results of principal component analysis and cluster analysis showed that the occurrence of CUOCPs is significantly affected by exogenous disturbance, which could be flood events; meanwhile, clusters of CUOCPs were found in both water and sediments in the source-limited middle reaches in urban areas. Redundancy analysis (RDA) showed that CUOCP occurrences were not positively correlated with nutrient elements (nitrogen and phosphorus), but related to pH and dissolved oxygen (DO), indicating complex sources.

Sources and Health Risk of Organochlorine Pesticides in Surface Water from Buerhatong River and Hunchun River in Northeast China

Sources and Health Risk of Organochlorine Pesticides in Surface Water from Buerhatong River and Hunchun River in Northeast China

Occurrence, spatial distribution, source, and ecological risk assessment of organochlorine pesticides in Dongting Lake, China.

The occurrence, distribution, sources, and ecological risks of organochlorine pesticides in Dongting Lake of China were investigated. The average concentrations of organochlorine pesticides (OCPs) in 22 surface water samples and 14 sediment samples were 90.07 ng/L and 80.65 ng/g dw, respectively. Sixteen types of OCPs, dominated by HCHs, DDTs and heptachlor, were detected in the Dongting Lake. The relationships of OCP residues between Dongting Lake and its tributary rivers have been discussed and the hydraulic connections with the Yangtze River and the Three Gorges Dam (TGD) were also considered. Results showed that the shortage of runoff, earlier dry season, and reduction of sediment deposition extremely deteriorated the hydraulic conditions, magnified the water cycle, and restrained the self-purification of OCPs. The ∑OCPs in surface water were concentrated in the inlets of Yangtze River, Lishui River, Zishui River, Yuanshui River, and Xiangjiang River. Moreover, the ∑OCPs in the outlet of the Yangtze River also maintained a high level, indicating that OCPs posed adverse effects on the Yangtze River. Risk assessments of OCPs in the surface water of Dongting Lake were estimated according to available water quality guidelines and health risk assessment models. The results indicated that OCPs in the surface water of Dongting Lake were safe for aquatic organisms and human health. In addition, sediment quality guidelines (SQGs) were also applied to evaluate the potential ecotoxicological risks of OCPs in sediments. The results presented that contaminants of γ-HCH; o,p'-DDD; and dieldrin in sediment had adverse effects on benthic organisms, indicating that fundamental solutions should be proposed to control OCP contamination in Dongting Lake.

Monitoring and bioremediation of organochlorine pesticides in surface water with Enterobacter asburiae

Aim of study: One of the safest techniques regarding the remediation of contaminated water is biological remediation. This study aimed to: (i) monitoring of a collection of organochlorine pesticides (OCPs) in three agricultural drainages (Nashart, no. 9, and El-shoka), located in Kafr El-Sheikh governorate, Egypt; and ii) investigate the biodegradation potential of different bacterial isolates regarding organochlorine pesticides.Material and methods: Analysis of OCPs was carried out by gas chromatography, Enrichment cultures were used for isolation of the bacterial strains capable of OCPs biodegradation and the most efficient isolate was identified based on morphological, biochemical ad molecular characteristics.Main results: The determination of OCPs in water samples by gas chromatography showed varying values of OCPs ranging from 0.0 mg/L (below detection limit) to 0.0385 mg/L. A total of four morphologically different bacterial isolates were obtained, which showed a remarkable capability of OCPs biodegradation detected in mineral salt medium containing 17 OCPs active ingredients by two approaches including the analysis of the OCP residues at the end of the incubation period and measuring the bacterial growth in terms of total viable count and optical density. The bacterial isolate N2 showed the highest degradation capability when the screening process was carried out to select the most efficient isolates, which was identified according to the morphological, biochemical and molecular characterization as Enterobacter asburiae.Research highlights: The biodegradation of OCPs using E. asburiae was proved to be a promising approach for the detoxification and removal of OCPs residues in aqueous systems.

Currently Used Organochlorine Pesticides in Surface Water and Sediments in Xiangjing River, a Drinking Water Source in China: Occurrence and Distribution Characteristics Under Flood Events

Currently Used Organochlorine Pesticides in Surface Water and Sediments in Xiangjing River, a Drinking Water Source in China: Occurrence and Distribution Characteristics Under Flood Events

Spatial distribution and sources of organochlorine pesticides in surface waters of Shanghai, China

The concentrations, distribution, influencing factors, and sources of 26 organochlorine pesticides (OCPs) were investigated in surface waters of Shanghai. Surface waters in this study refer to the freshwater that contains particles smaller than 0.45 μm in size. Total concentrations of OCPs ranged from 5.90 to 158.16 ng/L with a mean value of 78.11 ng/L. The OCP concentrations were generally low, but with a few relatively high concentrations at sites in the northern and southern regions of Shanghai. Dissolved oxygen, electrical conductivity, pH and oxidation–reduction potential had an important impact on the distribution of OCPs, which showed a significant negative correlation (p HCHs > Endosufan and Methoxychlor > Propachlor > Heptachlor and DDTs > Dacthal and Chlordane. The contribution of historic residual HCHs in Shanghai’s surface waters was not significantly different from that of atmospheric deposition, and a part of HCB was likely from the degradation of HCHs. DDTs were mainly from historical residues, although some were derived from recent inputs, and the main sources of heptachlors were also the historical residues. However, the recent input and historical residues of aldrins were both noticeable. The fluctuation of OCPs pollution levels and source differences among different intensive land-use types were relatively insignificant (p > 0.05).

Quantitation of Polycyclic Aromatic Hydrocarbons and Organochlorine Pesticides in Surface Waters

We develop an assay for the total content of xenobiotics from the polyaromatic hydrocarbon (PAH) and organochlorine pesticide (OCP) groups in samples of surface water containing suspended matter. It is found that the suspended matter isolated from water by filtration during sample preparation according to standard method ISO 5667:2006 may contain PAH and OCP xenobiotics. The xenobiotics containing in the filtrate and suspended matter isolated from water samples are extracted with n-hexane. After the extracts are concentrated by a factor of 250–1000, their qualitative and quantitative composition is determined by high-performance liquid phase chromatography with fluorescence detection and by gas chromatography mass spectrometry. For water samples, the limit of quantitation (LOQ) for OCP and PAH xenobiotics is found to be 0.1 and 0.005 μg/L, respectively, and in case of the suspended matter samples the LOQs are 0.1 and 0.005 ng/g. The determination error is expressed as the relative standard (mean-square) deviation Sr (%), and the completeness of xenobiotic extraction is expressed in per cents (r, %). The method is tested on samples of surface waters containing suspended matter in the range of 90 ± 10 to 2800 ± 50 mg/L. The developed method enables us to detect trace amounts of xenobiotics in water and in suspended matter in it. The method can be useful in studies of surface waters and in forecasting the level of contamination of aquatic environments with PAHs and OCPs released as a result of degradation of suspended matter that binds the xenobiotics.

Distribution and Risk Assessment of OCPs in Surface Water, Sediments, and Fish from Lake Gucheng and Inflow and Outflow Rivers

To investigate the distribution, source, and ecological risk of organochlorine pesticides (OCPs) residues in Lake Gucheng, surface water, sediment, and biological samples were collected from 12 sampling sites of Lake Gucheng and its inlets and outlets during summer and winter, and the concentrations of 19 OCPs were analyzed. The results showed that the concentration (dry weight) of OCPs in Lake Gucheng ranged from 26.74 to 48.12 ng·L-1 in surface water, 9.01 to 35.34 ng·g-1 in sediment, and 13.39 to 124.29 ng·g-1 in organisms. The pollution characteristics of OCPs in surface water showed that the concentration was much higher in summer than in winter, and much higher at inflow and outflow rivers than in farming ponds and the central region of Lake Gucheng; the seasonal pollution characteristics in sediment were not obvious. All 19 kinds of OCPs in water, sediment, and organisms were detected in different degrees, and the dominant contaminants were HCHs and DDTs. α-HCH was the main pollutant at all sites in both surface water and sediment, with 21% to 42% of total HCHs in two seasons. p,p'-DDD was the main pollutant in surface water with 30% to 76% of total DDTs, whereas p,p'-DDT was the main pollutant in sediment with 68% to 93% of total DDTs in two seasons. Source analysis based on ratios of HCHs isomers and DDTs isomers indicated that there was a new input of OCPs under anaerobic conditions in the study area. The ecological risk assessment showed that the OCPs in surface water did not lead to significant health risks, but the OCPs in sediments might pose ecological risks to the Lake Gucheng ecosystem. The organisms were within the acceptable potential carcinogenic risk range.

Organochlorine Pesticides in Surface Water of Jiuxi Valley, China: Distribution, Source Analysis, and Risk Evaluation

Residual levels of 11 organochlorine pesticides (OCPs) in surface water of Jiuxi Valley were determined during spring and autumn at nine sampling points to assess their contamination and potential risks. The water samples were extracted by solid-phase extraction (SPE), and OCPs were analyzed by gas chromatograph equipped with a 63Ni-ECD detector. The investigation results indicated that the concentration of total OCPs varied from 4.07 to 13.5 ng·L−1 with an average value of 7.15 ng·L−1 in spring, and from 12.5 to 30.1 ng·L−1 with an average value of 19.9 ng·L−1 in autumn. Jiuxi Valley was slightly contaminated by OCPs, and the concentrations of ΣHCHs and ΣDDTs in the river were at relatively low levels. HCHs were the main pollutant in spring, and also in autumn, and α-HCH was the main component of the HCH isomers at most sampling points. Source analysis indicated that local use of lindane or input of fresh γ-HCH contributed to the presence of HCHs. New inputs were the major sources of DDTs, aldrin, heptachlor, and endrin. The OCP levels of this investigation were within the standard limits set by a majority of the water quality standards and guidelines of China, WHO, European Union, and Canada. However, although the γ-HCH concentrations at all sampling sites, endrin concentrations at all sampling sites, and β-HCH concentrations at most sampling sites were below the human health water quality standard, and the levels of other tested OCPs (α-HCH, p,p′-DDD, p,p′-DDE, p,p′-DDT, aldrin, and heptachlor) exceeded the value of EPA-recommended water quality criteria for human health, which indicated potential risks to human health around the region.

An Assessment of Water and Sediment Quality of River in India with Special Reference to Pesticide Contamination, a Case Study

Drinking water quality has become a serious issue in many countries due to the scarcity of fresh water resources. Water quality monitoring is the first step for the management and conservation of aquatic system. The contamination of OrganoChlorine Pesticides (OCPs) is very harmful for the environment and human beings. The presence of OCPs in surface water and in the bottom sediment in the Chalakudy River was investigated to evaluate the pollution load and distribution level of OCP seasonally over a period of 3 years from January 2013 to December 2015. Surface water sample and bottom sediment were collected from nine different sites (upstream, midstream and downstream) and analyzed for their profile of important physicochemical parameters and for persistence of OCP. To know the present trends in the river clearly ,temporal distribution and spatial distribution of OCPs and other parameters are studied based on three season(winter, summer, and monsoon).Obtained trend in each year were compared through sampling and analysis.

Residues of organochlorine pesticides (OCPs) in aquatic environment and risk assessment along Shaying River, China.

Organochlorine pesticides (OCPs) are pesticides with global scale ubiquity, persistence and bioaccumulation, which leave long-term residuals in the water body. OCPs' high toxicity poses significant threats to human health and aquatic biodiversity, making assessment of OCPs' impact on aquatic ecology and human health urgently necessary. In this research, the presence of 16 OCPs in surface water and groundwater along Shaying River, China, as well as OCPs concentration correlations, was investigated at 24 selected sampling sites. At the same time, the ecological risk and human carcinogenic risk were also analyzed by risk quotient method and USEPA's Risk Assessment Guidance, respectively. Results showed that the total concentration of OCPs ranged from 21.0 to 61.4ngL-1 in groundwater, and 12.3-77.5ngL-1 in surface water. Hexachlorocyclohexane (HCHs) and heptachlor were the prominent contaminants in groundwater, which indicated their use in the recent past and confirmed their persistence. The α-HCH/γ-HCH ratios in groundwater confirmed that γ-HCH (lindane) was used as main substitute of technical HCH in the study area. The correlation analysis illustrated that δ-HCH and γ-HCH played a dominant role in HCHs residue. Heptachlor and α-HCH, as well as endosulfan and heptachlor epoxide, had a strongly significant positive correlation, suggesting an associated usage of the two pair OCPs. An extremely high ecological risk for aquatic organism was observed for γ-HCH, heptachlor and dieldrin, while the carcinogenic risks posed by the selected OCPs in surface water and groundwater were all acceptable.

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface water from the Yongding River basin, China: Seasonal distribution, source apportionment, and potential risk assessment

The presence of 17 polycyclic aromatic hydrocarbons (PAHs) and 15 persistent organochlorine pesticides (OCPs) in surface water of the Yongding River Basin was analyzed through GC/MS/MS during the spring and summer at 46 sampling sites. The goal was to investigate their seasonal distribution, possible sources, and potential risk. Our results showed that the total PAH concentration in surface water of Yongding River Basin ranged from 41.60 to 1482.60ng/L with a mean value of 137.85ng/L in the spring, and from 53.53 to 506.53ng/L with a mean value of 124.43ng/L in the summer. The total OCP concentration ranged from <0.08 to 197.71ng/L with a mean value of 7.69ng/L in the spring, and from <0.08 to 93.58ng/L with a mean value of 7.92ng/L in the summer. Moreover, the total PAH concentration was slightly lower in the spring than in the summer, whereas the total OCP concentration was similar between seasons. Source analysis indicated that combustion sources and petroleum sources both contributed to the presence of PAHs. Historical environmental residues and long range atmospheric transport were the major sources of HCH and DDT contamination. The concentrations of total PAHs and single PAHs including benz(a)anthracene, benzo(a)pyrene, benz(b)fluoranthene, and benz(k)fluoranthene in surface water at some sampling sites exceeded the water environmental quality standards of China and several other countries or organizations. This indicated a potential threat to human health from the consumption of aquatic organisms due to PAH bioaccumulation. The concentrations of α-HCH, p,p’-DDE, and p,p’-DDD at several sampling sites exceeded the limit for human health specified in the ambient water quality criteria developed by the US Environmental Protection Agency, which indicated that these pollutants provide potential hazards to the residents around the sampling sites.

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.

Seasonal Distribution, Composition, and Source Apportionment of Polycyclic Aromatic Hydrocarbons and Organochlorine Pesticides in the Main Stream of the Luanhe River

Occurrence of 17 polycyclic aromatic hydrocarbons (PAHs) and 15 persistent organochlorine pesticides (OCPs) were analyzed by gas chromatography coupled to tandem mass spectrometry (GC/MS/MS) during the spring and summer of 2015 in surface water at 14 sampling sites in the mainstream of the Luanhe River to elucidate their seasonal distribution, composition, and potential sources. Results showed that total PAH concentrations in the surface water of the Luanhe River ranged from 33.33 ng·L-1 to 90.65 ng·L-1(52.64 ng·L-1 in average) in spring and 147.68 ng·L-1 to 252.68 ng·L-1 (169.88 ng·L-1 in average) in summer, respectively, and total concentrations of OCPs ranged from <0.08 ng·L-1 to 3.48 ng·L-1 (1.19 ng·L-1 in average) in spring and <0.08 to 5.47 ng·L-1(1.02 ng·L-1 in average) in summer, respectively. Seasonal pollution characteristics of PAHs in surface water during two different seasons showed that total PAH concentrations were much higher in summer than in spring at each sampling site on the Luanhe River. While seasonal pollution characteristics of OCPs showed that total OCP concentrations were much lower in spring than in summer at six sites including Luanxian, Daheiting reservoir dam, Panjiakou Village, Guojiatun, Qujiawan, and Baichengzi, and were higher in spring than in summer at the remaining eight sites. From the perspective of spatial and temporal variations in the composition patterns of PAHs and OCPs in surface water of the Luanhe River, the low and middle ring species of PAHs were dominant in spring and summer and the proportion of PAHs with different rings showed significant differences. Three-ring PAHs dominated the samples with 51.18% and 67.55% (61.39% on average) of total PAHs in spring, and four-ring and two-ring PAHs accounted for 11.78%-33.94% (20.97% on average) and 13.31%-27.12% (16.94% on average), respectively. In the summer, In the summer, naphthalene(Nap) was the main component of total PAHs at each sampling site and PAHs were predominated by two-ring compounds with 77.08% and 90.62% (83.34% on average) of the total, and by three-ring and four-ring compounds with 7.09%-15.22% (12.40% on average) and 2.23%-7.49% (3.97% on average), respectively. Only the residues of hexachlorocyclohexanes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs) were detected in surface water of the Luanhe River at different degrees and HCHs were the dominant compounds. β-HCH was the main pollutant at most sampling sites with 43.78% and 70.09% (56.25% on average) of total HCHs in the spring and with 53.63% and 64.31% (58.37% on average) in the summer. α-HCH and γ-HCH were abundant at other sampling sites. Source analysis based on the isomer ratios indicated that PAHs in the Luanhe River mainly originated from combustion sources and also likely from petroleum processes. Ratios of OCPs confirmed that historical residues and long-range atmospheric transport were the major sources of HCHs in the study area, and new sources of lindane or γ-HCH existed at Wulongji and Sandaohezi in the spring and Daheting reservoir dam in the summer. Fresh inputs at the Panjiakou reservoir dam, Sandaohezi, Waigoumenzi, Baichengzi, Zhenglanqi, and the Shandianhe reservoir, and environmental residues at Jianggezhuang and Guojiatun were the major sources of DDTs. Concentrations of single PAHs in surface water of the Luanhe River did not exceed the water quality standards of China and other countries except that chrysene(Chr) exceeded the United States national water quality standard. Individual PAHs did not exceed any safety guidelines for aquatic organisms that are exposed to PAHs in water but total concentrations of PAHs exceeded the threshold limits set by the United States Environmental Protection Agency (EPA) and the European Union. This result indicated that consuming fish and other aquatic animals might pose a potential threat to human health due to the bioaccumulation of PAHs in aquatic organisms. The concentrations of OCPs in surface water of the Luanhe River did not exceed any water quality standards or the aquatic life threshold limits for freshwater developed by the EPA. However, the concentrations of α-HCH at Jianggezhuang, Wulongji, Qujiawan, and Baichengziand sites in the spring and at the Panjiakou reservoir dam, Panjiakou village, Qujiawan, and Baichengzi sites in the summer, and concentrations of p,p'-DDD at the Shandianhe reservoir and p,p'-DDE at Jianggezhuang, Sandaohezi, Guojiatun, and Shandianhe reservoir in the spring exceeded the human health ambient water quality criteria limit developed by the EPA. This result suggests that α-HCH, p,p'-DDE, and p,p'-DDD pose a potential health risk to the residents who live near the sampling sites on the Luanhe River.

Seasonal Pollution Characteristics and Source Identification of Polycyclic Aromatic Hydrocarbons and Organochlorine Pesticides in Surface Water of Baiyangdian Lake

Seasonal variations of 17 polycyclic aromatic hydrocarbons(PAHs) and 15 persistent organochlorine pesticides(OCPs) were analyzed during spring and summer in surface water from 12 sampling sites of Baiyangdian lake to elucidate their seasonal pollution characteristics and sources. The results showed that total concentrations of PAHs in surface water of Baiyangdian lake ranged from 35.38 to 88.06 ng·L-1(46.57 ng·L-1 in average) in spring and 25.64 to 301.41 ng·L-1(76.23 ng·L-1 in average) in summer, respectively, and total concentrations of OCPs ranged from 0.69 to 4.50 ng·L-1(1.77 ng·L-1 in average) in spring and 0.11 to 3.20 ng·L-1(0.90 ng·L-1 in average) in summer, respectively. Seasonal pollution characteristics of PAHs in surface water during two different seasons showed that the total concentration of PAHs was much higher in summer than in spring at three sampling sites of Baiyangdian lake including Qiantang, Guancheng and Anxin bridge, and the level of PAHs in spring was much higher than that in summer at the other nine sites. While seasonal pollution characteristics of OCPs showed that the total concentration of OCPs was much higher in summer than in spring in samples of Guancheng sites, and the level of OCPs in spring was slightly higher than that in summer in the rest of samples. From the perspective of spatial and temporal variations in the composition patterns of PAHs and OCPs in surface water of Baiyangdian lake, PAHs were predominated by 3-ring PAHs with 45.92% and 61.36%(52.60% in average) of total PAHs in spring, while in summer Nap was the chief component of 2-ring PAHs in three sampling sites including Qiantang, Guancheng and Anxin bridge with 84.91%, 91.04% and 78.10% of the total, respectively, and 3-ring PAHs were primary pollutants in the other nine sites with 37.14% to 53.90%(48.94% in average) of the total. Residues of HCHs and DDTs were detected in different degrees and β-HCH was the main pollutant at all sampling sites with 29.94% and 100%(59.87% in average) of total HCHs in spring, while β-HCH was the predominant compounds at five sampling sites with 57.55% and 80.23%(61.98% in average) in summer and α-HCHs and δ-HCH were abundant at other sampling sites. Source analysis based on isomer ratios indicated that the main source of PAHs in Baiyangdian lake originated from combustion sources, and additional sources for several sampling sites could be petroleum processes. Ratios of HCH isomers and DDT congeners confirmed that environmental historical residues and long range atmospheric transport were the major sources of OCPs contamination in the study area. Compared with the water quality standard of China and other countries or organizations, concentrations of PAHs and OCPs in surface water of Baiyangdian lake did not exceed the target values of the standard. However, the concentrations of α-HCH and p,p'-DDD in Anxin bridge and Quantou sites exceeded the limit of human health ambient water quality criteria developed by EPA, which reflected that α-HCH and p,p'-DDD would have a potential hazards risk to the residents from Baiyangdian district.