Bio-analytical and chemical characterisation of offshore produced water effluents for estrogen receptor (ER) agonists

The in vitro estrogen receptor (ER) agonist potency and C1 to C9 alkyl substituted phenol content of offshore produced water effluents collected from the UK sector of the North Sea were determined using a combination of bio-analytical and chemical analysis techniques. An in vitro reporter gene assay was used to determine ER agonist potency, whilst gas chromatography coupled to mass spectrometry (GC-MS) was used to quantify the concentration of alkylphenols. The in vitro ER agonist potency was highly variable and ranged from less than the limit of detection (theoretically 0.03 ng 17beta-estradiol (E2) l(-1)) to 91 ng E2 l(-1). C1 to C5 alkylphenol concentrations were also highly variable ranging from 5 to 1600 microg l(-1) with a median concentration of 206 microg l(-1). These data reflect the highly variable composition of produced water discharges from different fields. The observed poor correlation of the alkylphenol isomer content and ER agonist activity suggests that other compounds present in the produced water discharges may be responsible for the ER agonist activity observed. It is recommended that further work be performed to characterise the full range of ER agonists present in offshore produced water discharges.     

Changes in thyroid peroxidase activity in response to various chemicals

Thyroperoxidase (TPO) is a large heme-containing glycoprotein that catalyzes the transfer of iodine to thyroglobulin during thyroid hormone (TH) synthesis. Previously, we established an in vitro assay for TPO activity based on human recombinant TPO (hrTPO) stably transfected into human follicular thyroid carcinoma (FTC-238) cells. It is important to determine whether environmental chemicals can disrupt TPO activity because it is an important factor in the TH axis. In this study, we used our assay to examine the changes in TPO activity in response to various chemicals, including benzophenones (BPs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs). Overall, BPs, PAHs, and POPs slightly altered TPO activity at low doses, as compared with the positive controls methimazole (MMI), genistein, and 2,2',4,4'-tetrahydroxy BP. Benzophenone, benzhydrol, 3-methylchloranthracene, pyrene, benzo(k)fluoranthene, benzo(e)pyrene, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and heptachlor decreased TPO activity, while 2,4-dihydroxy BP, 2,2'-dihydroxy-4-methoxy BP, and dibenzo(a,h)anthracene increased TPO activity. From these data, we can predict the disruption of TPO activity by various chemicals as a sensitive TH end point. TPO activity should be considered when enacting measures to regulate environmental exposure to thyroid-disrupting chemicals.     

Polybrominated diphenyl ethers (PBDEs) in the riverine and marine sediments of the Laizhou Bay area, North China

62 riverine and marine sediments were collected from the Laizhou Bay area, where the largest manufacturing base of brominated flame retardants (BFRs) in Asia is located. Eight polybrominated diphenyl ethers (PBDEs) were analyzed to investigate the impact of rapidly-developed bromine industries on the regional aquatic system. PBDE concentrations varied largely in riverine sediments. Σ(7)PBDEs (including BDE 28, 47, 99, 100, 153, 154 and 183) and BDE 209 ranged from 0.01 to 53 ng g(-1) dw and from 0.74 to 285 ng g(-1) dw with a mean value of 4.5 ng g(-1) dw and 54 ng g(-1) dw, respectively, indicating a strong influence of direct pollution discharges from local factories. In marine sediments, Σ(7)PBDEs and BDE 209 ranged from not detected (nd) to 0.66 ng g(-1) dw and from 0.66 to 12 ng g(-1) dw with a mean value of 0.32 ng g(-1) dw and 5.1 ng g(-1) dw, respectively. PBDE concentrations were mostly <10 ng g(-1) dw for Σ(7)PBDEs and <50 ng g(-1) dw for BDE 209, which are at a relatively low level for monitored riverine and coastal sediments around the world. Even at the most contaminated sites in Laizhou Bay area, PBDE concentrations were not among the highest concentrations reported in the literature. Congener compositions were dominated by BDE 209 (57.2-99.9% of the sum of BDE congeners), with minor contributions from penta- and octa-BDE products. Tri- to octa-BDE congeners were well correlated among each other (r > 0.75) and thus sources from similar mixing of penta- and octa-BDE products were suggested in this area. Compared with riverine sediments, a much better correlation between PBDE concentrations with TOC was observed in marine environment. The congener pattern changed and their correlation coefficients among each other were remarkably reduced. Contributions of BDE 28, 47 and 99 to Σ(7)PBDEs were generally the same in almost all the marine sites, while it was distinctively higher for BDE 153. These are probably attributable to several reasons, such as contributions by atmospheric deposition and/or redistribution between particles of various sizes during and/or after fluvial transportation combined with the difference of physiochemical properties of BDE congeners.     

PBDEs in marine and freshwater sediments from Belgium: levels, profiles and relations with biota

Sediments from the Belgian North Sea (BNS), the Western Scheldt Estuary (SE) and freshwater watercourses from the Scheldt basin were analysed for eight PBDE congeners, namely BDEs 28, 47, 99, 100, 153, 154, 183 and 209. Previously analysed biological samples from the same locations in the BNS and the SE have been shown to contain large amounts of PBDEs. Surprisingly, PBDE concentrations in the sediments were below the LOQ for samples from the BNS (except BDE 209), while in those from the SE the sum of PBDEs (not including BDE 209) were higher and ranged from 0.20 to 0.41 ng g(-1) dw. BDE 209 could be detected in 83% of the samples from the BNS and in all the samples from the SE. Concentrations up to 1200 ng g(-1) were hereby measured in the SE. Compared to the marine and estuarine locations, the sediments from the freshwater watercourses were relatively more polluted with the lower brominated PBDEs (<0.20-19 ng g(-1) dw). BDE 209 concentrations up to 320 ng g(-1) dw were measured in those sediments. However, the contribution of BDE 209 to the total amount of PBDEs varied much more at the freshwater locations than in the SE, which suggests a different input of pollutants. PBDE profiles observed in biological samples do not match the profiles of the sediments. BDE 183 and 209 could not be quantified in biota, although these congeners were undoubtedly present in the sediments. This raises questions about the bioavailability of these congeners in the environment.     

Brominated flame retardants in plasma samples from three different occupational groups in Norway

Brominated flame retardants (BFRs) are widely used in plastics, textile coatings, electrical appliances and printed circuit boards to prohibit the development of fires. In order to investigate how exposure to BFRs is related to specific occupations, samples were obtained from Norwegian individuals working at an electronics dismantling facility, in the production of printed circuit boards, or as laboratory personnel. Nine BFRs were quantified in the plasma samples: 2,4,4'-tribromodiphenyl ether (BDE-28), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether (BDE-100), 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE-154), 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183), 2,4,6-tribromophenol (TriBP) and tetrabromobisphenol A (TBBP-A). The BFRs were extracted from plasma using solid-phase extraction (SPE). The plasma lipids were decomposed by treatment with concentrated sulfuric acid directly on the SPE column, prior to the elution of the BFRs. Following diazomethane derivatization, the samples were analysed by gas chromatography-electron capture mass spectrometry. The subjects working at the electronics dismantling plant had significantly higher plasma levels of TBBP-A and BDE-153 compared to the other groups, and the heptabrominated congener BDE-183 was only detected in plasma from this group. TriBP was generally the most abundant BFR present, and the plasma concentrations were in the range 0.17-81 ng g-1 lipids. BDE-47 was the dominant BDE congener in all the individual samples and the levels were in the range 0.43-14.6 ng g-1 lipids. The total amounts of the seven BDEs were 8.8, 3.9 and 3.0 ng g-1 lipids for the group of electronics dismantlers, circuit board producers and laboratory personnel, respectively. Generally, large variations in the individual concentration levels were found within the groups, especially in the group of electronics dismantlers, where the relative standard deviations for BDE concentrations were in the range 23-164%. The levels of BFRs were not correlated to age or the level of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The present work indicates that the population in Norway is exposed to several BFRs, probably with food as a major source. The elevated level of higher brominated BDEs and TBBP-A in the plasma from the workers at the dismantling plant suggests an additional occupational exposure for these individuals. Thus, human exposure to BFRs seems to originate from a combination of different sources; however, further studies investigating plasma samples from a larger number of individuals are necessary for a more complete assessment of human exposure pathways to these environmental contaminants.     

Sensitive immunoassay detection of multiple environmental chemicals on protein microarrays using DNA/dye conjugate as a fluorescent label

Indirect competitive immunoassays were developed on protein microarrays for the sensitive and simultaneous detection of multiple environmental chemicals in one sample. In this assay, a DNA/SYTOX Orange conjugate was employed as an antibody label to increase the fluorescence signal and sensitivity of the immunoassays. Epoxy-modified glass slides were selected as the substrate for the production of 4 × 4 coating antigen microarrays. With this signal-enhancing system, competition curves for 17β-estradiol (E2), benzo[a]pyrene (BaP) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were obtained individually on the protein microarray. The IC(50) and calculated limit of detection (LOD) are 0.32 μg L(-1) and 0.022 μg L(-1) for E2, 37.2 μg L(-1) and 24.5 μg L(-1) for BaP, and 31.6 μg L(-1) and 2.8 μg L(-1) for BDE-47, respectively. LOD of E2 is 14-fold lower than the value reported in a previous study using Cy3 labeled antibody (Du et al., Clin. Chem, 2005, 51, 368-375). The results of the microarray immunoassay were within 15% of chromatographic analysis for all three pollutants in spiked river water samples, thus verifying the immunoassay. Simultaneous detection of E2, BaP and BDE-47 in one sample was demonstrated. There was no cross-reaction in the immunoassay between these three environmental chemicals. These results suggest that microarray-based immunoassays with DNA/dye conjugate labels are useful tools for the rapid, sensitive, and high throughput screening of multiple environmental contaminants.     

Pollution levels of thiobencarb, propanil, and pretilachlor in rice fields of the muda irrigation scheme, Kedah, Malaysia

The purpose of this study was to investigate the potential risk of pretilachlor, thiobencarb, and propanil pollutants in the water system of the rice fields of the Muda area. The study included two areas that used different irrigation systems namely non-recycled (N-RCL) and recycled (RCL) water. Regular water sampling was carried out at the drainage canals during the weeding period from September to October 2006 in the main season of 2006/2007 and April-May 2007 in off season of 2007. The herbicides were extracted by the solid-phase extraction method and identified using a GC-ECD. Results showed that the procedure for identification of the three herbicides was acceptable based on the recovery test values, which ranged from 84.1% to 96.9%. A wide distribution pattern where more than 79% of the water samples contained the herbicide pollutants was observed at both the areas where N-RCL and RCL water was supplied for the two seasons. During September to October 2006, high weedicide residue concentration was observed at the N-RCL area and it ranged from 0.05 to 1.00 μg/L for pretilachlor and propanil and 10-25 μg/L for thiobencarb. In the case of the area with RCL water, the weedicide residue ranged from 1 to 5 μg/L for pretilachlor and propanil and 10-25 μg/L for thiobencarb. The highest residue level reached was 25-50, 50-100, and 100-200 μg/L for pretilachlor, propanil, and thiobencarb, respectively. During April to May 2007, high residue concentration frequently occurred at the area supplied with N-RCL irrigation water and it ranged from 0.05 to 1.00, 10 to 25, and 25 to 50 μg/L for pretilachlor, propanil, and thiobencarb, respectively. The highest residue level reached was 25-50 μg/L for pretilachlor and 100-200 μg/L for propanil and thiobencarb. There was an accelerated increase in the concentration of the herbicide residues, with the maximum levels reached at the early period of weedicide application, followed by a sharp decrease after the rice fields were completely covered with the rice crop. During the main season of 2006/2007, the concentration of propanil residue gradually rose, although that of the other herbicides declined.     

A novel in vitro exposure technique for toxicity testing of selected volatile organic compounds

Exposure to vapours of volatile chemicals is a major occupational and environmental health concern. Toxicity testing of volatile organic compounds (VOCs) has always faced significant technological problems due to their high volatility and/or low solubility. The aim of this study was to develop a practical and reproducible in vitro exposure technique for toxicity testing of VOCs. Standard test atmospheres of xylene and toluene were generated in glass chambers using a static method. Human cells including: A549-lung derived cell lines, HepG2-liver derived cell lines and skin fibroblasts, were grown in porous membranes and exposed to various airborne concentrations of selected VOCs directly at the air/liquid interface for 1 h at 37 degrees C. Cytotoxicity of test chemicals was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) and NRU (neutral red uptake) assays following 24 h incubation. Airborne IC(50) (50% inhibitory concentration) values were determined using dose response curves for xylene (IC(50)=5350+/- 328 ppm, NRU; IC(50)=5750+/- 433 ppm, MTS in skin fibroblast) and toluene (IC(50)=0 500+/- 527 ppm, NRU; IC(50)=11,200 +/- 1,044 ppm, MTS in skin fibroblast). Our findings suggest that static direct exposure at the air/liquid interface is a practical and reproducible technique for toxicity testing of VOCs. Further, this technique can be used for inhalational and dermal toxicity studies of volatile chemicals in vitro as the exposure pattern in vivo is closely simulated by this method.     

Short-range transport of contaminants released from e-waste recycling site in South China

The transport behaviors of a suite of contaminants released from electronic waste (e-waste) recycling operations, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and heavy metals, were evaluated by analyzing the contaminant residues in surface soils sampled in the surrounding area of an e-waste recycling site in South China. Concentrations of PBDEs and PCBs in the soil samples ranged from 0.565 to 2908 ng g(-1) dw and from 0.267 to 1891 ng g(-1) dw, respectively, while soil residues were 0.082-2.56, 3.22-287, and 16.3-162 μg g(-1) dw for Cd, Cu, and Pb, respectively. Concentrations of PBDEs and PCBs in soil decreased with increasing distance from the source of pollution, indicating possible PBDE and PCB contamination in the surrounding areas due to the short-range transport of these compounds from the e-waste recycling site. Although no significant difference in the short-range transport potential among PBDE and PCB congeners was observed, reductions in concentrations of the highly-brominated-BDEs and highly-chlorinated-CBs were slightly quicker than those of their less-halogen-substituted counterparts. Conversely, heavy metals showed the lowest transport potential due to their low vapor pressure, and results showed metals would remain near the pollution source instead of diffusing into the surrounding areas. Finally, mass inventories in areas near the e-waste site were 0.920, 0.134, 0.860, 4.68, 757, and 673 tons for BDE209, PBDEs (excluding BDE209), PCBs, Cd, Cu, and Pb, respectively.     

A suite of microplate reader-based colorimetric methods to quantify ammonium, nitrate, orthophosphate and silicate concentrations for aquatic nutrient monitoring

A sensitive, accurate and rapid analysis of major nutrients in aquatic systems is essential for monitoring and maintaining healthy aquatic environments. In particular, monitoring ammonium (NH(4)(+)) concentrations is necessary for maintenance of many fish stocks, while accurate monitoring and regulation of ammonium, orthophosphate (PO(4)(3-)), silicate (Si(OH)(4)) and nitrate (NO(3)(-)) concentrations are required for regulating algae production. Monitoring of wastewater streams is also required for many aquaculture, municipal and industrial wastewater facilities to comply with local, state or federal water quality effluent regulations. Traditional methods for quantifying these nutrient concentrations often require laborious techniques or expensive specialized equipment making these analyses difficult. Here we present four alternative microcolorimetric assays that are based on a standard 96-well microplate format and microplate reader that simplify the quantification of each of these nutrients. Each method uses small sample volumes (200 μL), has a detection limit ≤ 1 μM in freshwater and ≤ 2 μM in saltwater, precision of at least 8% and compares favorably with standard analytical procedures. Routine use of these techniques in the laboratory and at an aquaculture facility to monitor nutrient concentrations associated with microalgae growth demonstrates that they are rapid, accurate and highly reproducible among different users. These techniques offer an alternative to standard nutrient analyses and because they are based on the standard 96-well format, they significantly decrease the cost and time of processing while maintaining high precision and sensitivity.