Occurrence, distribution and seasonal variations of polychlorinated biphenyls and polybrominated diphenyl ethers in surface waters of the East Lake, China

Health Risk Assessment of Pesticide Residues in Drinking Water of Upper Jhelum Region in Kashmir Valley-India by GC-MS/MS

Globally growing demand for agricultural and farm foods has more or less become dependent on chemical pesticides to maintain the supply chain, which undoubtedly boosts agricultural production. However, pesticides not only impact the target pests but cause hazard to human health. Pesticides are ubiquitous and can be found in almost every component of the environment. They can therefore impair human and biota health when present over the threshold level. The present study assessed the concentration of commonly used pesticides for agricultural purposes but get mixed in different sources of water, as such fifteen sampling sites along the upper Jhelum basin of Kashmir valley were chosen. For the analysis, 60 water samples were obtained from different water sources. Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine pesticide residues in water samples. Pesticide residues from 10 of the 26 commonly used pesticides were detected in water samples. Difenoconazole had the highest concentration among the pesticides detected, with a mean concentration of 0.412 ± 0.424 μg/L ranging from 0.0 μg/L to 0.8196 μg/L. The target hazards quotient (THQ) was used to quantify the possible noncarcinogenic health risks associated with drinking pesticide-contaminated water. Only chlorpyrifos and quinalphos were detected >1 in RWS3 (1.6571), RWS4 (1.0285), RWS14 (1.2571), and RWS15 (1.2000) sample sites, implying that the drinking water poses a health risk to humans. Hence, pesticide hazards should be mitigated and rigorous monitoring is needed to reduce pesticide residues in drinking water.

Spatial monitoring and health risk assessment of polybrominated diphenyl ethers in environmental matrices from an industrialized impacted canal in South Africa

This study investigates the pollution of Markman stormwater runoff, which is a tributary to Swartkops River Estuary. Solid-phase and ultrasonic extraction methods were utilized in the extraction of water and sediment samples, respectively. The pH of the sampling sites was above the EU guideline. The ranges of concentration of [Formula: see text]PBDE obtained in water and sediment samples for all the seasons were 58.47-1357 ng/L and 175-408 ng/g, respectively. Results also showed that BDE-66 was the dominant congener, specifically in the industrial zone, where its concentrations ranged from 2 to 407 ng/g in sediment. Consequently, the high concentration of BDE- 66 in the sediment of stormwater calls for concern. Penta-BDE suggests potential moderate eco-toxicological risk, as evident in the calculated risk assessment. The result showed possible photodegradation along the contaminant's travel time, as only 7% of the PBDE was detected at the point of entry into the Swartkops River Estuary. Markman stormwater may be contributing heavily to the pollution load of Swartkops River, as evident in the alarming concentrations of PBDEs obtained. The industries at this zone should eliminate the contaminants before discharging their effluents into the canal.

Occurrence and Risk Assessment of Polybrominated Diphenyl Ethers in Surface Water and Sediment of Nahoon River Estuary, South Africa

The concentrations, potential sources, and compositional profile of PBDEs in the surface water and sediment of Nahoon Estuary, East London, South Africa, were investigated with solid-phase extraction and ultra-sonication, respectively, followed by gas-chromatography-electron capture detection. The seasonal range of the contaminants’ concentrations in water and sediment samples in spring season were ∑PBDE 329 ± 48.3 ng/L (25.32–785 ng/L) and ∑PBDE 4.19 ± 0.35 ng/g dw (1.91–6.57 ng/g), but ∑PBDE 62.1 ± 1.50 ng/L (30.1–110 ng/L) and ∑PBDE 65.4 ± 15.9 ng/g dw (1.98–235 ng/g) in summer, respectively. NH1 (first sampling point) was the most contaminated site with PBDE in the Estuary. The potential source of pollution is attributed to the stormwater runoff from a creek emptying directly into the Estuary. This study’s dominant PBDE congener is BDE-17, ranging from below detection limit to 247 ng/L and 0.14–32.1 ng/g in water and sediment samples, respectively. Most detected at all the sites were BDE-17, 47, 66, and 100. Most BDE-153 and 183 are found in sediment in agreement with the fact that higher brominated congeners of PBDE adsorb to solid materials. There was no correlation between the congeners and organic carbon and organic matter. However, the human health risk assessment conducted revealed that the PBDE concentration detected in the estuary poses a low eco-toxicological risk. Nevertheless, constant monitoring should be ensured to see that the river remains safe for the users, as it serves as a form of recreation to the public and a catchment to some neighbourhoods.

Determination of multiple organic flame retardants in maricultural water using High-volume/High-throughput Solid-phase extraction followed by liquid/gas chromatography tandem mass spectrometry

A rapid and efficient analytical method is proposed and optimized for the enrichment, extraction and instrument analysis of four typical organic flame retardants (OFRs), including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDs) and dechlorane compounds (Dechloranes) in maricultural waters using High-volume/High-throughput Solid-phase extraction with in-situ ultrasonic technique followed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and gas chromatography tandem mass spectrometry (GC-MS) instrumental detection. The optimized pretreatment conditions were that the analytes were enriched by XAD-2 resins and eluted repeatedly with 50 mL hexane/acetone (1:1, v:v) for 5 min. The results of method validation exhibited that the developed method can be used for quantitative detection of 11 OPEs, 13 PBDEs, 3 HBCDs and 5 Dechloranes in water samples. The method detection limits (MDLs) and limits of quantification (LOQs) are 0.4-26.2 pg/L and 1.5-87.4 pg/L for OPEs, 23.3-35.4 pg/L and 77.5-117.9 pg/L for HBCDs, 0.8-97.4 pg/L and 2.6-324.7 pg/L for PBDEs and 9.3-78.5 pg/L and 31.0-261.8 pg/L for Dechloranes, respectively. The method was successfully applied in lagoon maricultural areas in Hainan province, and the results showed that 4 OFRs were detected in almost all water samples. Total concentrations of 18 water samples were 1.89-39.97 ng/L for OPEs, 0.18-5.40 ng/L for PBDEs, ND-0.24 ng/L for HBCDs and 0.01-1.77 ng/L for Dechloranes, respectively. The optimized analytical method is highly sensitive and efficient with expectation to play an essential role in monitoring the ultra-trace organic pollutants and providing an effective risk assessment in ecological environment.

Critical risk analysis of metals toxicity in wastewater irrigated soil and crops: a study of a semi-arid developing region

Toxic elemental exposure through consumption of contaminated crops is becoming a serious concern for human health. Present study is based on the environment and health risk assessment of wastewater irrigated soil and crops in a semi-arid region Faisalabad, Pakistan. The concentrations of potentially toxic elements (Cu, Cr, Mn, Fe, Pb, Zn, Ni) were analysed by atomic absorption spectrometer in five different crops (Corn, rice, wheat, sugarcane and millet), while, their topsoil's and multi targeted risks analysis were assessed. Results showed, the mean values of Pb and Zn were higher in crop than Food and Agriculture Organization guidelines for food additives and contaminants. A strong positive correlation was found among wastewater and crop's toxic metals (r2 values in Cu, Zn, Pb, Ni and Cr were 0.913, 0.804, 0.752, 0.694, 0.587 respectively). Whereas, a strong correlation was also found among soil and wastewater lead (r2 = 0.639). The calculations of Nemerow Integrated Pollution Index (NIPI) showed the soil samples maximum pollution limit (NIPI > 3) and Potential Ecological Risk Index (PERI) was found to be higher than maximum limit (PERI > 600) for all samples. While, for non-carcinogenic risk, Hazard Index (HI) values in adult were near threshold (HI > 1) for all crop samples. In children, the HI values for Corn, Rice and Wheat were above threshold limit and for Sugarcane and Millet, these were near to threshold. Cancer risk values for Cr found higher than safe limit (1 × 10-6) in adult and children for crop samples. Crop irrigation by wastewater irrigation is a prominent alternative option for water scarce countries, however prior testing and treatment of such wastewater streams must be employed to minimize the adverse impacts on human health and environment.

Xenopus laevis as a Bioindicator of Endocrine Disruptors in the Region of Central Chile

One of the direct causes of biodiversity loss is environmental pollution resulting from the use of chemicals. Different kinds of chemicals, such as persistent organic pollutants and some heavy metals, can be endocrine disruptors, which act at low doses over a long period of time and have a negative effect on the reproductive and thyroid system in vertebrates worldwide. Research on the effects of endocrine disruptors and the use of bioindicators in neotropical ecosystems where pressure on biodiversity is high is scarce. In Chile, although endocrine disruptors have been detected at different concentrations in the environments of some ecosystems, few studies have been performed on their biological effects in the field. In this work, Xenopus laevis (African clawed frog), an introduced species, is used as a bioindicator for the presence of endocrine disruptors in aquatic systems with different degrees of contamination in a Mediterranean zone in central Chile. For the first time for Chile, alterations are described that can be linked to exposure to endocrine disruptors, such as vitellogenin induction, decreased testosterone in male frogs, and histological changes in gonads. Dioxin-like and oestrogenic activity was detected in sediments at locations where it seem to be related to alterations found in the frogs. In addition, an analysis of land use/cover use revealed that urban soil was the best model to explain the variations in frog health indicators. This study points to the usefulness of an invasive species as a bioindicator for the presence of endocrine-disruptive chemicals.

The occurrence of polybrominated diphenyl ether (PBDE) contamination in soil, water/sediment, and air

As a kind of brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs) are extensively used in different types of electronic equipment, furniture, plastics, and textiles. PBDEs are ubiquitous environmental contaminants that may impact human health and ecosystems. Here we highlight recent findings on the occurrence, contamination status, and transport of PBDEs in soil, water/sediment, and air. Four aspects are discussed in detail: (1) sources of PBDEs to the environment; (2) occurrence and transport of PBDEs in soil; (3) PBDEs in aquatic ecosystems (water/sediment) and their water-sediment partitioning; and (4) the occurrence of PBDEs in the atmosphere and their gas-particle partitioning. Future prospects for the investigation on PBDEs occurrence are also discussed based on current scientific and practical needs.

Persistent Halogenated Organic Pollutants in Surface Water in a Megacity: Distribution Characteristics and Ecological Risks in Wuhan, China

Surface water pollution in megacities is strongly linked to human and environmental health, and surface water quality has deteriorated sharply recently because of increasing persistent halogenated organic pollutant (HOP) concentrations. In the present study, we collected 112 water samples from 14 lakes and 11 drinking water sources in Wuhan, China, and analyzed them for two typical groups of HOPs: polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The mean values of the ΣPCB concentrations were 4.34 and 10.05 ng L^-1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53 ng L^-1 in winter and summer, respectively. The PCB and PBDE concentrations at most sites in summer were significantly higher than those in winter, probably because of heavy stormwater runoff in summer. The degree of urbanization predicted from the population density was positively correlated with ΣPCB concentrations in the drinking water sources in summer. PBDE and PCB composition analysis suggested the major sources were penta-BDE and Aroclor mixtures. Risk assessments showed the PBDEs in water from the Zhuankou site exceeded the threshold set by the European Union, which could result in adverse effects on aquatic organisms. Negligible noncarcinogenic risks were found for PCBs and PBDEs in the surface water with regard to drinking and bathing. However, the carcinogenic risks of PCBs for bathing in surface water were higher than the safe level of 1.00 × 10^-6, implying that the surface water in Wuhan is not safe for bathing.

Organohalogenated Contaminants (OHCs) in Surface Sediments and Water of East Dongting Lake and Hong Lake, China

East Dongting Lake and Hong Lake are two typical lakes in the middle watershed of the Yangtze River, China. The differences in the hydrological condition and human activities of the region may result in the differences in concentrations, distribution, and sources of contaminants. The levels, sources, distribution, and ecological risk of OHCs, including 15 OCPs, 7 PCBs, and 7 PBDEs in surface sediments and water from this region, were investigated. OCPs and PCBs were the predominant pollutants in water and sediments samples, respectively. Source analysis showed that HCHs, PBDEs, and PCBs were mainly from the historical input of commercial products, but there were recent discharges of DDT into the water. The spatial distribution of OHCs showed that higher levels of OHCs in sediments and water were found in the sampling sites far away from the estuary of Hong Lake, but such obvious distribution characteristic was not found in East Dongting Lake. TOC played a crucial role in the retention of OCPs in the sediments of Hong Lake, but significant correlation between TOC and OCPs for East Dongting Lake, TOC and PCBs or PBDEs for both lakes were not found. The possible adverse biological effects could be caused by OCPs residues in sediments of both lakes, and it was worse for Hong Lake. The noncarcinogenic and carcinogenic risk assessment of HCHs and DDTs indicated the water quality of both lakes was safe for bathing and drinking. The potential ecotoxicological risks of PBDEs and PCBs of both lakes were rather low.

Accounting for water levels and black carbon-inclusive sediment-water partitioning of organochlorines in Lesser Himalaya, Pakistan using two-carbon model

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

Fluorescent microarray for multiplexed quantification of environmental contaminants in seawater samples

The development of a fluorescent multiplexed microarray platform able to detect and quantify a wide variety of pollutants in seawater is reported. The microarray platform has been manufactured by spotting 6 different bioconjugate competitors and it uses a cocktail of 6 monoclonal or polyclonal antibodies raised against important families of chemical pollutants such as triazine biocide (i.e. Irgarol 1051®), sulfonamide and chloramphenicol antibiotics, polybrominated diphenyl ether flame-retardant (PBDE, i.e. BDE-47), hormone (17β-estradiol), and algae toxin (domoic acid). These contaminants were selected as model analytes, however, the platform developed has the potential to detect a broader group of compounds based on the cross-reactivity of the immunoreagents used. The microarray chip is able to simultaneously determine these families of contaminants directly in seawater samples reaching limits of detection close to the levels found in contaminated areas (Irgarol 1051®, 0.19 ± 0,06 µg L^-1; sulfapyridine, 0.17 ± 0.07 µg L^-1; chloramphenicol, 0.11 ± 0.03 µg L^-1; BDE-47, 2.71 ± 1.13 µg L^-1; 17β-estradiol, 0.94 ± 0.30 µg L^-1 and domoic acid, 1.71 ± 0.30 µg L^-1). Performance of the multiplexed microarray chip was assessed by measuring 38 blind spiked seawater samples containing either one of these contaminants or mixtures of them. The accuracy found was very good and the coefficient of variation was < 20% in all the cases. No sample pre-treatment was necessary, and the results could be obtained in just 1 h 30 min. The microarray shows high sample throughput capabilities, being able to measure simultaneously more than 68 samples and screen them for a significant number of chemical contaminants of interest in environmental screening programs.

Occurrence and distribution of halogenated flame retardants in an urban watershed: Comparison to polychlorinated biphenyls and organochlorine pesticides

Due to restrictions on polybrominated diphenyl ethers (PBDEs), market demand for alternative flame retardants is projected to increase, worldwide. Information regarding the environmental behavior of these compounds is limited. The present study involved field measurements of several alternative halogenated flame retardants (HFRs), along with PBDEs and legacy persistent organic pollutants (POPs) in surface water, bottom sediments and suspended particulate matter (SPM) within a highly urbanized watershed in Singapore. Several alternative HFRs were detected in water and sediments. Dechlornane Plus stereoisomers (syn- and anti-DP) were detected in all samples, exhibiting relatively high concentrations in water, sediments and SPM. The maximum syn-DP concentrations in water, sediments and SPM were 24.30 ng/L, 2.48 ng/g dry wt. and 7774 ng/g dry wt., respectively. 1,2-Bis(2,4,6-tribromophenoxy) ethane (BTBPE), pentabromotoluene (PBT), hexabromobenzene (HxBBz) and tetrabromoethylcyclohexane (TBECH) were routinely detected. PBDE concentrations were relatively low and often non-detectable. Polychlorinated biphenyl (PCB) concentrations ranged from 0.017 to 8.37 ng/L in water, 9.86-27.92 ng/g dry wt. in SPM, and 6.48-212.3 ng/g dry wt. in sediments. Congener and isomer patterns suggested no recent inputs of PBDEs or dichlorodiphenyltrichloroethane (DDT). Rainfall was found to be an important factor influencing temporal and spatial patterns of DPs, BTBPE, PBDEs and some organochlorines in surface water. Land use index was found to be important for several organochlorines, but not HFRs. The observed sediment-water partitioning behavior of the studied HFRs and legacy POPs was highly dependent on chemical hydrophobicity. The data demonstrate that the studied HFRs have a relatively high affinity for SPM and bottom sediments. For example, the log K_OC,OBS for TBECH, syn-DP and anti-DP and BTBPE in bottom sediments ranged between 8.1 and 9.6. The findings will aid future studies regarding fate, transport and bioaccumulation of these current-use contaminants of concern.

Occurrences of Organochlorine Pesticides along the Course of the Buffalo River in the Eastern Cape of South Africa and Its Health Implications

Most organochlorine pesticides (OCPs) which are increasingly used in agriculture and industry are not biodegradable and thereby persist in the environment for a very long period of time. They are capable of negatively impacting the health of humans and biota when present in a higher concentration than recommended. This study evaluated the concentrations of 17 OCPs in surface water samples collected from six sampling sites along the course of the Buffalo River in Eastern Cape, South Africa, between December 2015 and May 2016. The samples were subjected to solvent extraction, followed by florisil clean up, and analyzed using gas chromatography coupled with an electron capture detector. The individual concentrations of OCPs detected ranged from <LOD to 4403 ng/L in summer and <LOD to 313 ng/L in autumn. The levels of OCPs in the study area were generally above the United State Environmental Protection Agency (USEPA) limit of 100 ng/L in all the sampling locations in the two seasons. The cancer risk assessment values were below the permissible limit of the 10⁻⁶ level, although the life average daily dose were slightly above the USEPA maximum limits of 10⁻⁴. Therefore, there is a need for the adequate regulation of agrochemical storage, use, and disposal in this province and other parts of South Africa.

Elevated Concentrations of 4-Bromobiphenyl and 1,3,5-Tribromobenzene Found in Deep Water of Lake Geneva Based on GC×GC-ENCI-TOFMS and GC×GC-μECD

We quantified the concentrations of two little-studied brominated pollutants, 1,3,5-tribromobenzene (TBB) and 4-bromobiphenyl (4BBP), in the deep water column and sediments of Lake Geneva. We found aqueous concentrations of 625 ± 68 pg L^-1 for TBB and 668 ± 86 pg L^-1 for 4BBP over a depth range of 70-191.5 m (near-bottom depth), based on duplicate measurements taken at five depths during three separate 1 month sampling periods at our sampling site near Vidy Bay. These levels of TBB and 4BBP were 1 or 2 orders of magnitude higher than the quantified aqueous concentrations of the components of the pentabrominated biphenyl ether technical mixture, which is a flame retardant product that had a high production volume in Europe before 2001. We observed statistically significant vertical concentration trends for both TBB and 2,2',4,4',6-pentabromobiphenyl ether in the deep water column, which indicates that transport and/or degradation processes affect these compounds. These measurements were enabled by application of a comprehensive two-dimensional gas chromatograph coupled to an electron capture negative chemical ionization time-of-flight mass spectrometer (GC×GC-ENCI-TOFMS) and to a micro-electron capture detector (GC×GC-μECD). GC×GC-ENCI-TOFMS and GC×GC-μECD were found to be >10× more sensitive toward brominated pollutants than conventional GC×GC-EI-TOFMS (with an electron impact (EI) ionization source), the latter of which had insufficient sensitivity to detect these emerging brominated pollutants in the analyzed samples. GC×GC also enabled the estimation of several environmentally relevant partitioning properties of TBB and 4BBP, further confirming previous evidence that these pollutants are bioaccumulative and have long-range transport potential.

Characterization of PBDEs and novel brominated flame retardants in seawater near a coastal mariculture area of the Bohai Sea, China

The concentrations and distributions of PBDEs and novel brominated flame retardants (NBFRs) in dissolved phase of surface seawater near a coastal mariculture area of the Bohai Sea were investigated. The total concentrations of PBDE and NBFRs were in the range of 15.4-65.5 and 2.12-13.6ng/L, respectively. The highest concentration was discovered in the water near an anchorage ground, whereas concentrations in water samples from offshore cage-culture area were not elevated. Relatively high concentrations of BDE28, 99, and 100 were discovered in the medium range of distance from shore, where is the path of tidal or coastal current. This suggested that inputs from ships or through tidal current rather than mariculture activities may be the main sources of BFRs in this area. BDE209, BDE47, hexabromobenzene (HBB), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) were the most abundant BFR congeners. Relatively high proportions of these BFRs may originate from discharge of wastewater nearby or degradation from higher brominated PBDEs. No correlations were found between BFR concentrations and water dissolved organic carbon, suggesting that concentrations and distributions of BFRs in this area were source-dependent. The relatively high concentrations in this study emphasized the importance of monitoring and managing BFR contaminations in mariculture areas of China.

Occurrence investigation of perfluorinated compounds in surface water from East Lake (Wuhan, China) upon rapid and selective magnetic solid-phase extraction

Using a novel magnetic nanocomposite as adsorbent, a convenient and effective magnetic solid-phase extraction (MSPE) procedure was established for selective separation and concentration of nine perfluorinated compounds (PFCs) in surface water sample. Then an ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) system was employed for detection of PFCs. Good linearity of the developed analytical method was in the range of 0.5-100 ng L^-1 with R² > 0.9917, and the limits of detection (LODs) ranged from 0.029 to 0.099 ng L^-1. At three fortified concentrations of 0.5, 5 and 50 ng L^-1, the spiked recoveries of PFCs were in the range of 90.05-106.67% with RSDs < 12.62% (n = 3). The proposed analytical method was applied for determination of PFCs in surface water from East Lake (Wuhan, China). The total concentrations of nine PFCs ranged from 30.12 to 125.35 ng L^-1, with perfluorooctane sulfonate and perfluoroctanoic acid as the most prevalent PFCs, and the greatest concentrations of PFCs were observed in Niuchao lakelet. The concentrations of the PFCs (C ≥ 11) were mostly less than the limits of quantification (LOQs), attributed to the possibility that the more hydrophobic long-chain PFCs are potential to accumulate in sediment and aquatic biota.

Organochlorine pesticides and polychlorinated biphenyls in surface water around Beijing

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

Effects of carbonaceous materials on microbial bioavailability of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) in sediments

In this study, we investigated the influence of various types of carbonaceous materials (CMs) on the bioavailability of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) to polybrominated diphenyl ether (PBDE)-degrading microorganisms in CM-amended sediments. The microbial debromination ratio of BDE-47 was reduced by 92.8%-98.2% in the 5.0% CM-amended sediment compared with in sediment without CM amendment after 100 d of anaerobic incubation. The concentrations of lower brominated products also decreased when the content of CMs increased from 0.2% to 5.0%. The inhibitory effects of CMs on BDE-47 debromination were CM content- and characteristic-specific. The reciprocals of BDE-47 debromination ratios and lower brominated product concentrations showed positive linear correlations with CM contents in sediments (p<0.01), and the slopes of linear regression fitting generally correlated with specific surface areas (SSAs) of CMs. Desorption of BDE-47 from CMs indicated the declined desorbing fraction of BDE-47 was responsible for the reduction in BDE-47 bioavailability to microorganisms, thus decreasing its debromination in sediments amended with CMs. This study revealed that CM amendment could reduce the PBDE bioavailability to PBDE-degrading microorganisms in sediments, and it is expected to help deepen our understanding of the environmental behaviors and risks of PBDEs.

Uptake, translocation and metabolism of decabromodiphenyl ether (BDE-209) in seven aquatic plants

Terrestrial plant uptake of PBDEs from contaminated soils has been widely reported recently. In this study the fate of deca-BDE within a plant/PBDEs/aquatic environment system was investigated through simulated pot experiments. Accumulations of the total PBDEs and deca-BDE were observed in tissues of seven test aquatic plant species, namely Phragmites australis, Cyperus papyrus, Alternanthera philoxeroides, Colocasia esculenta, Scirpus validus, Acorus calamus and Oryza sativa. In all seven plants, O. sativa leads the uptake and accumulation both in the total PBDEs (444.8 ng g(-1)) and deca-BDE (368.0 ng g(-1)) in roots. Among the six common phytoremediation aquatic plants, A. calamus leads the uptake (236.2 ng g(-1)), and P. australis leads the translocation (Cshoot/Croot = 0.35), while A. philoxeroides (43.4%) and P. australis (80.0%) lead in the metabolism efficiencies in the root and shoot, respectively. The detection of seventeen lesser brominated PBDE congeners provided the debromination evidence, and the specific PBDEs profiles in test plant species indicated there is no common metabolic pattern. Furthermore, a relative high proportion of lesser brominated PBDE congeners in shoots suggested the possible metabolic difference between roots and shoots. Finally, a noticeable percentage of penta- and octa-BDE derived from deca-BDE also hint the ecological risk in deca-BDE use. This comparative research on the aquatic plants provide a broad vision on the understanding of plant/PBDEs/aquatic environment interaction system, and may be applied to remediate PBDEs in contaminated waters and sediments.

Microbial bioavailability of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) in natural sediments from major rivers of China

Microbial degradation plays a crucial role in eliminating polybrominated diphenyl ethers (PBDEs) in environments. However, the microbial bioavailability of PBDEs in aquatic sediments is not well understood. In this work, the bioavailability of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), a typical PBDE congener, to PBDE-degrading microorganisms in natural sediments from six Chinese rivers under anaerobic conditions was investigated. The contents of black carbon (BC) and total organic carbon (TOC) in the six sediment samples were in the range of 0.025%-0.30% and 0.03%-3.38%, respectively. BDE-47 desorption from various sediments was fitted well with the first-order three-compartment desorption model. The desorbing fraction of sediment-associated BDE-47 at each desorption time interval exhibited a significant negative correlation with the BC content (p < 0.01). In the sediments, the anaerobic debromination of BDE-47 by microorganisms underwent a stepwise debromination pathway generating mainly three lower brominated congeners (BDE-28, -17 and -4). The microbial debromination ratio of BDE-47 ranged from 4.21% to 7.89% in various sediments after 120 d incubation anaerobically, and it negatively correlated with the content of sediment BC significantly (p < 0.01). However, the desorbing fraction and microbial debromination ratio of BDE-47 only showed weak correlations with the TOC content in sediments (p > 0.05). Furthermore, there was a significant positive correlation of desorbing fraction of BDE-47 from sediments with its microbial debromination ratio (p < 0.01) as well as with the level of its three lower brominated products (p < 0.05) after the first 20 d incubation. This study suggests that the BDE-47 bioavailability to microorganisms in anaerobic river sediments is mainly influenced by the content of sediment BC which controls the desorbing fraction of sediment-associated BDE-47.

Occurrence, distribution and risk assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in nine water sources

Water quality of water sources is a critical issue for human health in South China, which experiences rapid economic development and is the most densely populated region in China. In this study, the pollution of organohalogen compounds in nine important water sources, South China was investigated. Twenty six organohalogen compounds including seventeen polychlorinated biphenyls (PCBs) and nine polybrominated diphenyl ethers (PBDEs) were detected using gas chromatograph analysis. The concentrations of total PCBs ranged from 0.93 to 13.07ngL(-1), with an average value of 7.06ngL(-1). The total concentrations of nine PBDE congeners were found in range not detected (nd) to 7.87ngL(-1) with an average value of 2.59ngL(-1). Compositions of PCBs and PBDEs indicated the historical use of Aroclors 1248, 1254 and 1260, and commercial PBDEs may be the main source of organohalogen compounds in water sources in South China. The nine water sources could be classified into three clusters by self-organizing map neural network. Low halogenated PCBs and PBDEs showed similar distribution in the nine water sources. Cancer risks of PCBs and PBDEs via water consumption were all below 10(-6), indicating the water quality in the nine water sources, South China was safe for human drinking.

The temporal distribution, source and potential toxicity of polycyclic aromatic hydrocarbons in a sediment core from an urban lake in Wuhan, China

The urban lakes in China, especially those with relatively small areas and closed watersheds, have suffered from serious pollution and are at a high risk of eutrophication due to the small amount of concern given to them. The temporal distribution profile, source apportionment and potential toxicity of parent polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs (APAHs) in a sediment core from an urban shallow lake with the above specifications, in the middle and lower reaches of the Yangtze River, China, were investigated in the present study. Parent PAHs, especially 4-6 ring ones, were dominant in the sediment core. The vertical profiles of 16 anthropogenic US Environmental Protection Agency (EPA) priority PAHs increased from a depth of 50 cm to 30 cm, then slightly decreased to the surface. However, biogenic perylene content decreased from bottom to surface. Most of the APAHs increased in concentration from bottom to surface. Source apportionment of EPA PAHs indicated the pyrogenic source was dominant in the sediment core. The domestic combustion of bituminous coal, coal tar and biomass can be identified as the main factors responsible for this. Toxicity assessment of selected parent PAHs demonstrated that benzo(a)pyrene accounted for the largest part of the toxic equivalent quantity (TEQ), and PAHs in the studied area possibly imposed adverse biological effects, especially for benthic organisms. Therefore, action should be taken to prevent an increase in the contamination from PAHs in the studied area, as well as in similar urban lakes in China, based on the specificity of individual watersheds.

Occurrence and fate of selected endocrine-disrupting chemicals in water and sediment from an urban lake

Occurrence of five endocrine-disrupting chemicals (EDCs)-bisphenol-A (BPA), triclosan (TCS), 17α-ethinyl estradiol (EE2), benzophenone-3, and 4-methylbenzylidene camphor-were monitored in East Lake, the largest urban lake in China. Other than EE2, all selected EDCs were detected at least once in the lake water with concentrations ≤89.1 ng/L. EDCs were detected with greater occurrence in spring than in other seasons. In lake sediment, TCS was detected at the greatest concentration (30.9 ng g(-1)), whereas BPA and EE2 were not detected. Spatial distribution of the EDCs in the lake water and the lake sediment showed similar patterns, and greater EDC residuals were found from those sites with known wastewater input. The linear adsorption coefficients (K d) varied from 17.9 to 1,017 L kg(-1) and were related to the octanol-water partition coefficient (K ow) values of the compounds. Photodegradation was a major process removing the EDCs from the lake water, and the presence of dissolved organic material and NO3 (-) in the lake water can accelerate the photodegradation process. Degradation of the EDCs in the lake sediment was relatively slow and occurred mainly due to the microbial processes. All compounds were found more persistent under anoxic conditions than under oxic conditions.

Concentrations and risk assessment of polychlorinated biphenyls and polybrominated diphenyl ethers in surface sediments from the East Lake, China

The concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface sediment samples collected from the East Lake, China in winter 2012 and summer 2013 were analyzed in this study. The total PCB and PBDE concentrations ranged from not detected to 107.1 ng g(-1) dw and from 9.7 to 151.3 ng g(-1) dw, respectively. PCB-28, 101 and 180 were dominant congeners in both winter and summer. BDE-28 (44 %) was the dominant congener in winter and summer, followed by BDE-99 (28 %) and BDE-47 (26 %). The concentrations of PCBs in the sediment samples collected in summer were higher than those in winter, while the concentrations of PBDEs did not show much seasonal variations. Source analysis showed that the PCBs probably originated from urban runoff, industrial pollution and atmospheric deposition, and the PBDEs probably originated from historical usage of penta-BDE mixtures. Potential eco-toxicological risks caused by PCBs were found in about 5 % of the sampling sites; PBDEs had moderate eco-toxicological risk in 80 % sampling sites in the East Lake, China.

Simulation research on the natural degradation process of PBDEs in soil polluted by e-waste under increased concentrations of atmospheric O(3)

There have been increased concerns regarding the effect of polybrominated diphenyl ethers (PBDEs) on the environment. These compounds are widely utilized by the electronics industry and also function as fire retardants. More data on the basic characteristics of PBDEs are needed to better understand and used to describe their environmental fate. The aim of this study was to investigate the degradation of BDE-209 with different degrees of bromination under changes in the atmospheric environment. BDE-209 was able to be removed quickly due to the strong oxidizing ability of ozone in the atmosphere environment. Less-brominated BDEs, ranging from BDE-28 to BDE-183, were formed progressively, and the reaction of ozone gradually occupied the main position along with an increase in ozone flow time. Degradation reaction rates of PBDEs increased with increasing ozone concentration but decreased with increasing soil depth. Under UV-irradiation, BDE-209 was quickly transformed into less-brominated BDEs and the photodegradation reactions were faster than solar irradiation. The conditions of high ground temperature in the summer and alkaline soil were both contributors to the degradation of PBDEs. These results could facilitate the improvement of waste treatment designs and lead to better predictions of the outcome of PBDEs in the environment.