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.

    • "As these SPMDs had been previously deployed in the aquatic environment, the test organisms were thus exposed to mixtures directly collected in the field. In a number of these studies chemical analysis was performed on the passive sampler extracts in which mostly polycyclic aromatic hydrocarbons (PAHs) (Petty et al., 2000; Rastall et al., 2004; Bopp et al., 2007; Ke et al., 2007; Hillwalker et al., 2010; Emelogu et al., 2013), polychlorinated biphenyls (PCBs) (Petty et al., 2000; Hillwalker et al., 2010; Emelogu et al., 2013) and pesticides (Petty et al., 2000; Shaw et al., 2009; Hillwalker et al., 2010; Pesce et al., 2011; Morin et al., 2012) were the target substances. "
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    ABSTRACT: This study presents a new approach in aquatic toxicity testing combining passive sampling and passive dosing. Polydimethylsiloxane sheets were used to sample contaminant mixtures in the marine environment. These sheets were subsequently transferred to ecotoxicological test medium in which the sampled contaminant mixtures were released through passive dosing. 4 out of 17 of these mixtures caused severe effects in a growth inhibition assay with a marine diatom. These effects could not be explained by the presence of compounds detected in the sampling area and were most likely attributable to unmeasured compounds absorbed to the passive samplers during field deployment. The findings of this study indicate that linking passive sampling in the field to passive dosing in laboratory ecotoxicity tests provides a practical and complimentary approach for assessing the toxicity of hydrophobic contaminant mixtures that mimics realistic environmental exposures. Limitations and opportunities for future improvements are presented. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Mar 2015 · Marine Pollution Bulletin
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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.
    Full-text · Article · Jan 2014 · Environmental Science and Pollution Research
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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.
    Full-text · Article · May 2013 · Science of The Total Environment
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