Investigating the significance of dissolved organic contaminants in aquatic environments: Coupling passive sampling with in vitro bioassays

Institute for Innovation, Design and Sustainability in Research (IDEAS), Robert Gordon University, Aberdeen AB10 1FR, UK.
Chemosphere (Impact Factor: 3.34). 07/2012; 90(2). DOI: 10.1016/j.chemosphere.2012.06.041
Source: PubMed


We investigated the feasibility of coupling passive sampling and in vitro bioassay techniques for both chemical and ecotoxicological assessment of complex mixtures of organic contaminants in water. Silicone rubber passive sampling devices (SR-PSDs) were deployed for 8-9weeks in four streams and an estuary of an agricultural catchment in North East (NE) Scotland. Extracts from the SR-PSDs were analysed for freely dissolved hydrophobic organic contaminants (HOCs) and screened for wide range of pesticides. The total concentrations of dissolved PAHs (∑PAH(40), parent and branched) in the water column of the catchment varied from 38 to 69ngL(-1), whilst PCBs (∑PCB(32)) ranged 0.02-0.06ngL(-1). A number and level of pesticides and acid/urea herbicides of varying hydrophobicity (logK(OW)s ∼2.25 to ∼5.31) were also detected in the SR extracts, indicating their occurrence in the catchment. The acute toxicity and EROD induction potentials of SR extracts from the study sites were evaluated with rainbow trout liver (Oncorhynchus mykiss; RTL-W1) cell line. Acute cytotoxicity was not observed in cells following 48h exposure to the SR extracts using neutral red uptake assay as endpoint. But, on a sublethal level, for every site, statistically significant EROD activity was observed to some degree following 72h exposure to extracts, indicating the presence of compounds with dioxin-like effect that are bioavailable to aquatic organisms in the water bodies of the catchment. Importantly, only a small fraction of the EROD induction could be attributed to the PAHs and PCBs that were determined. This preliminary study demonstrates that the coupling of silicone rubber passive sampling techniques with in vitro bioassays is feasible and offers a cost effective early warning signal on water quality deterioration.

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    • "Only two sheets out of the six SR sheets for bioassay use from each site, including the procedural blank (undeployed SR samplers), were extracted in the first instance . In the first sampling campaign, the extracts from each site were evaluated for acute cytotoxicity and potential to induce cytochrome P4501A enzyme activity (Emelogu et al. 2013a). The remaining four sheets from each site were preserved in amber coloured flasks at −20 °C for future evaluations of toxicity. "
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    ABSTRACT: A wide variety of organic contaminants including pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have previously been detected in surface waters in the river Ythan catchment, North East Scotland UK. While the concentrations detected were below Water Framework Directive Environmental Quality Standards (WFD-EQSs) environmental exposures to the diverse mixtures of contaminants, known and unknown, may pose chronic and/or sublethal effects to non target organisms. The present study assessed the embryo and algal toxicity potential of freely dissolved organic contaminants from the Ythan catchment using silicone rubber passive sampling devices (SR-PSDs) and miniaturised bioassay techniques. Zebrafish (Danio rerio) embryos and marine phytoplankton species (Diacronema lutheri) were exposed to extracts from SR-PSDs deployed at different locations along the river Ythan and an undeployed procedural blank. Statistically significant developmental and algal toxicities were measured in all tests of extracts from deployed samples compared with the procedural blanks. This indicates environmental exposure to, and the combined toxicity potential of, freely dissolved organic contaminants in the catchment. The present and previous studies in the Ythan catchment, coupling SR-PSDs and bioassay techniques, have both helped to understand the interactions and combined effects of dissolved organic contaminants in the catchment. They have further revealed the need for improvement in the techniques currently used to assess environmental impact.
    Environmental Science and Pollution Research 01/2014; 21(8). DOI:10.1007/s11356-013-2488-x · 2.83 Impact Factor
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    • "(ECD) for PCBs and tandem MS for pesticides and acid/urea herbicides. The detailed descriptions of the analytical procedures including the quality control and assurance procedures and the limits of detection and quantification (LOD and LOQ) are described in previous studies by Emelogu et al. (2013a,b). Tables 1 A, B and C (supporting information; S.I) show the summary of the PAHs, PCBs and pesticides and acid/urea herbicides targeted in this study. "
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    ABSTRACT: As an alternative procedure to conventional water quality assessment, the presence and combined toxicity of dissolved organic contaminants in water at five sites in the Forth estuary and the Firth of Forth, Scotland, United Kingdom was investigated using silicone rubber passive sampling devices (SR-PSDs) and an algal growth inhibition bioassay. SR-PSDs were deployed in water at the five sites for ~2months. Following retrieval, extracts from the deployed SR-PSDs were assessed for both algal growth inhibition and the occurrence of a wide range of organic contaminants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and a variety of plant protection products (PPPs; commonly referred to collectively as 'pesticides'). The 72h algal growth inhibition test was performed using a native marine phytoplankton (Diacronema lutheri) in 24 well microplates. Freely dissolved (e.g. bioavailable) concentrations of PAHs and PCBs were determined using performance reference compounds (PRCs). The algal toxicity tests exhibited varied effects at the five sites indicating the presence of, and exposure to, phytotoxic compounds and their potential toxicity in the Forth. The individual and total dissolved concentrations of 40 PAHs and 32 PCBs measured in the study were relatively low and showed input of petrogenic, atmospheric and sewage related sources. Several pesticides of diverse polarities were identified in the water suggesting sources from both riverine input and direct discharges. The study thus illustrates the value of combining bioassays and chemical analysis (with effective sampling technique) for a realistic and rapid assessment of organic contaminants in the aquatic environment.
    Science of The Total Environment 05/2013; 461-462C:230-239. DOI:10.1016/j.scitotenv.2013.05.011 · 4.10 Impact Factor
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    • "From the amount of PAHs and PCBs sequestered by the SR samplers and the site specific R S , the dissolved time weighted average concentration (C TWA ) of PAHs and PCBs were calculated using an empirical uptake model that is valid for both equilibrium, transitional and linear uptake system (Smedes and Booij, 2012). A more detailed description on how these methods were applied to derive the C TWA of PAHs and PCBs, including the quality control procedures, are provided in Emelogu et al. (2013). The accuracy of the estimated dissolved concentrations of the PAHs and PCBs is highly dependent on the values of log K SW and R S used. "
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    ABSTRACT: This study evaluates the potential of silicone rubber passive sampling devices (SR-PSDs) as a suitable alternative to automatic water samplers (autosamplers) for the preliminary identification of a wide range of organic contaminants in freshwater systems. The field performance of SR-PSDs deployed at three sites on two streams of an agricultural catchment area in North East (NE) Scotland, United Kingdom (UK) was assessed concurrently with composite water samples collected from two of the sites using autosamplers. The analytical suite consisted of selected plant protection products (PPPs; commonly referred to collectively as 'pesticides'), including 47 pesticides and a separate sub-category of 22 acid/urea herbicides. Of these, a total of 54 substances, comprising 46 pesticides and 8 urea herbicides were detected in at least one of the SR samplers. All but 6 of these SR-PSD detected substances were quantifiable. By comparison, a total of 25 substances comprising 3 pesticides and 22 acid/urea herbicides were detected in the composite water samples, of which only 8 acid/urea herbicides were quantifiable. The larger number and chemical classes of compounds detected and quantified via passive sampling reflect the lower limits of detection achieved by this device when compared to autosamplers. The determination of dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) added to the information on contaminant pressures at each site, allowing assessment of the reliability of SR-PSDs in freshwater systems and the identification of possible contaminant sources. The study demonstrated the utility of SR-PSDs for detecting and semi-quantifying low concentrations of analytes, including those which hitherto have not been measured in the catchment area and also some pesticides that are no longer approved for agricultural use in the UK and EU. The SR-PSD approach can thus provide a better understanding and clearer picture of the use and presence of organic contaminants within catchments.
    Science of The Total Environment 01/2013; 445-446C:261-272. DOI:10.1016/j.scitotenv.2012.12.053 · 4.10 Impact Factor
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