Bioassay battery interlaboratory investigation of emerging contaminants in spiked water extracts – Towards the implementation of bioanalytical monitoring tools in water quality assessment and monitoring

Abstract

Bioassays are particularly useful tools to link the chemical and ecological assessments in water quality monitoring. Different methods cover a broad range of toxicity mechanisms in diverse organisms, and account for risks posed by non-target compounds and mixtures. Many tests are already applied in chemical and waste assessments, and stakeholders from the science-police interface have recommended their integration in regulatory water quality monitoring. Still, there is a need to address bioassay suitability to evaluate water samples containing emerging pollutants, which are a current priority in water quality monitoring. The presented interlaboratory study (ILS) verified whether a battery of miniaturized bioassays, conducted in 11 different laboratories following their own protocols, would produce comparable results when applied to evaluate blinded samples consisting of a pristine water extract spiked with four emerging pollutants as single chemicals or mixtures, i.e. triclosan, acridine, 17α-ethinylestradiol (EE2) and 3-nitrobenzanthrone (3-NBA). Assays evaluated effects on aquatic organisms from three different trophic levels (algae, daphnids, zebrafish embryos) and mechanism-specific effects using in vitro estrogenicity (ER-Luc, YES) and mutagenicity (Ames fluctuation) assays. The test battery presented complementary sensitivity and specificity to evaluate the different blinded water extract spikes. Aquatic organisms differed in terms of sensitivity to triclosan (algae > daphnids > fish) and acridine (fish > daphnids > algae) spikes, confirming the complementary role of the three taxa for water quality assessment. Estrogenicity and mutagenicity assays identified with high precision the respective mechanism-specific effects of spikes even when non-specific toxicity occurred in mixture. For estrogenicity, although differences were observed between assays and models, EE2 spike relative induction EC values were comparable to the literature, and E2/EE2 equivalency factors reliably reflected the sample content. In the Ames, strong revertant induction occurred following 3-NBA spike incubation with the TA98 strain, which was of lower magnitude after metabolic transformation and when compared to TA100. Differences in experimental protocols, model organisms, and data analysis can be sources of variation, indicating that respective harmonized standard procedures should be followed when implementing bioassays in water monitoring. Together with other ongoing activities for the validation of a basic bioassay battery, the present study is an important step towards the implementation of bioanalytical monitoring tools in water quality assessment and monitoring.

Risk‐based approach in the revised European Union drinking water legislation: Opportunities for bioanalytical tools

“…As soon as the usefulness of an in vitro bioassay for EBM is established on the criteria described above (in an order that suits the urgency of information needed to draw such a conclusion), harmonized standard procedures can further improve reproducibility. For several bioassays it has already been demonstrated that comparable results can be achieved in interlaboratory studies (Escher et al ; Mehinto et al ; Di Paolo et al ).…”

Future water quality monitoring: improving the balance between exposure and toxicity assessments of real-world pollutant mixtures

“…Clearly, using ecological data to determine the link to specific chemical pollutants will remain elusive and of limited resolution for the foreseeable future due to the lack of diagnostic power of existing methods and/or the presence of multiple stressors, e.g., in urbanized areas. Bioassays are a complementary method to improve the detection of potential adverse effects from toxicologically relevant compounds and to help account for combination effects from mixture exposure [1,13,18,70]. Moreover, if we strive to exit from the uncertainty bias (i.e., drive effect assessments by uncertainty factors to bridge the knowledge gaps), it is vital to add effect-based observations to the samples being assessed for chemical contamination.…”

Alternative Management of Oil and Gas Produced Water Requires More Research on Its Hazards and Risks

“…">In vitro methods for characterizing toxicity provide valuable information on produced water toxicity. Emerging predictive toxicology tools (i.e., in vitro methods) should be investigated alongside in vivo methods to help assess the utility of newer methods for evaluating produced water potential hazards and risks (Di Paolo et al ) because in vivo approaches are important for evaluating complex endpoints that are difficult to assess without whole organism testing (e.g., developmental endpoints). High total dissolved solids (TDS) in produced water is a key obstacle to comprehensive assessment of produced‐water toxicity.…”