Environmental risk assessment of combined effects in aquatic ecotoxicology: A discussion paper

Abstract

Environmental regulatory edicts within the EU, such as the regulatory framework for chemicals REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), the Water Framework Directive (WFD), and the Marine Strategy Framework Directive (MSFD) focus mainly on toxicity assessment of individual chemicals although the effect of contaminant mixtures is a matter of increasing concern. This discussion paper provides an overview of the field of combined effects in aquatic ecotoxicology and addresses some of the major challenges related to assessment of combined effects in connection with environmental risk assessment (ERA) and regulation. Potentials and obstacles related to different experimental, modelling and predictive ERA approaches are described. On-going ERA guideline and manual developments in Europe aiming to incorporate combined effects of contaminants, the use of different experimental approaches for providing combined effect data, the involvement of biomarkers to characterize Mode of Action and toxicity pathways and efforts to identify relevant risk scenarios related to combined effects are discussed.

Estimating the Exposure of Coral Reefs and Seagrass Meadows to Land-Sourced Contaminants in River Flood Plumes of the Great Barrier Reef: Validating a Simple Satellite Risk Framework with Environmental Data

“…A cumulative risk magnitude score was then calculated for each plume water type ( Figure 3B, hereafter Magnitude Score or MS CCx ) by normalising across plume water type (Equations (2) and (3)). Concentration addition has been suggested as the "general solution" to the problem of calculating an expected quantitative effect for any combination of agents, and when their mechanisms of action are unknown [20,[87][88][89].…”

“…There is, however, a need to improve these remote sensing monitoring products and incorporate them into unique Risk Assessment Frameworks focusing on the GBR-wide scale and incorporating the potential of cumulative impacts from multiple contaminants in river plume waters [13,16]. The assessment of risk in this study is defined as "the methods by which the likely adverse effect of combined contaminants on ecosystems is estimated with a known degree of certainty using scientific methodology" [20]. Risk management approaches are becoming increasingly more common [21] in a range of applications including fisheries science [22,23], marine spatial planning [24] and ecosystem management [25,26].…”

Probing the xeno-oestrogenic impact of sediment cores contaminated by the pulp and paper industry: induction of aromatase cyp19a1b in late larval zebrafish

“…Evidence for adverse reproductive responses in fishes exposed to municipal sewages and kraft mill discharges constitute considerable proof that most realistic environmental contamination is a product of combination, and not of isolated chemicals (Beyer et al 2014). The prediction of non-interactive joint effects is based on the concentration addition (CA) model, where mixture-components with similar MoA are considered, whereas the independent action (IA) model, also named as response addition, predicts combined response based on different modes of action (Hertzberg and MacDonell 2002).…”

“…Xenoestrogenic chemicals act additively at environmentally relevant concentrations (Brian et al 2005), though synergism in laboratory studies is not common (in vitro, Silva et al 2002, Staal et al 2007in vivo, Sun et al 2009). Somewhat surprisingly, current regulatory emphasis in Europe, as enacted by European chemical legislation such as REACH and the Water Framework Directive (WFD), discuss toxicity of chemicals with similar MoA (Syberg et al 2009, SCHER, SCCS, SCENIHR 2012, Beyer et al 2014. The practise underestimates the potencies and roles of sub-threshold concentrations of chemicals with dissimilar MoA occurring as environmental mixtures.…”

Influência antrópica no ambiente aquático sobre os processos fisiológicos associados à maturação oocitária em peixes teleósteos

“…Os testes realizados para os experimentos ecotoxicológicos, em laboratório, são classificados de acordo com o comprimento do experimento relativizado com a vida do indivíduo e a complexidade da comunidade biológica, havendo três tipos de estudos tóxicos em animais, os testes de toxidade agudo, de toxicidade sub-crônico e crônico (Szynkowska e Sawlaczyk, 2014 Mesmo com os inúmeros testes apontados acima, a complexidade do ambiente e o grande número de contaminantes químicos torna impossível a realização de testes em laboratórios integrando todas estas variáveis (Beyer et al, 2014). Sendo assim, é necessário realizar uma abordagem que analisa a ecotoxicidade de diversos agentes químicos, sendo esta denominada de avaliação de risco ambiental (ERA da sigla em inglês environmental risk assessment).…”