Environmental risk assessment in a contaminated estuary: An integrated weight of evidence approach as a decision support tool

Abstract

Environmental risk assessment of complex ecosystems such as estuaries is a challenge, where innovative and integrated approaches are needed. The present work aimed at developing an innovative integrative methodology to evaluate in an impacted estuary (the Sado, in Portugal, was taken as case study), the adverse effects onto both ecosystem and human health. For the purpose, new standardized lines of evidence based on multiple quantitative data were integrated into a weight of evidence according to a best expert judgment approach. The best professional judgment for a weight of evidence approach in the present study was based on the following lines of evidence: i) human contamination pathways; ii) human health effects: chronic disease; iii) human health effects: reproductive health; iv) human health effects: health care; v) human exposure through consumption of local agriculture produce; vi) exposure to contaminated of water wells and agriculture soils; vii) contamination of the estuarine sedimentary environment (metal and organic contaminants); viii) effects on benthic organisms with commercial value; and ix) genotoxic potential of sediments. Each line of evidence was then ordinally ranked by levels of ecological or human health risk, according to a tabular decision matrix and expert judgment. Fifteen experts scored two fishing areas of the Sado estuary and a control estuarine area, in a scale of increasing environmental risk and management actions to be taken. The integrated assessment allowed concluding that the estuary should not be regarded as impacted by a specific toxicant, such as metals and organic compounds hitherto measured, but by the cumulative risk of a complex mixture of contaminants. The proven adverse effects on species with commercial value may be used to witness the environmental quality of the estuarine ecosystem. This method argues in favor of expert judgment and qualitative assessment as a decision support tool to the integrative management of estuaries. Namely it allows communicating environmental risk and proposing mitigation measures to local authorities and population under a holistic perspective as an alternative to narrow single line of evidence approaches, which is mandatory to understand cause and effect relationships in complex areas like estuaries.

Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays

“…It has been suggested that risk assessment frameworks and decision support systems consider the genotoxicity of chemical mixtures as part of a weight of evidence approach. This has been demonstrated by the method integrating nine lines of evidence in contaminated estuaries in Portugal ( Caeiro et al, 2017 ), the policy frameworks and risk assessment tools at contaminated sites in the Netherlands ( Dagnino et al, 2008 ), and the acceptance of genotoxic tools as one of the standard monitoring strategies within the European Union Water and Marine Strategy Framework Directives ( Allan et al, 2006 ; Martins & Costa, 2015 ).…”

Peer Review #1 of "Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays (v0.1)"

“…It has been suggested that risk assessment frameworks and decision support systems consider the genotoxicity of chemical mixtures as part of a weight of evidence approach. This has been demonstrated by the method integrating nine lines of evidence in contaminated estuaries in Portugal (Caeiro et al 2017), the policy frameworks and risk assessment tools at contaminated sites in the Netherlands (Dagnino et al 2008), and the acceptance of genotoxic tools as one of the standard monitoring strategies within the European Union Water and Marine Strategy Framework…”

Risk assessment of pesticides in estuaries: a review addressing the persistence of an old problem in complex environments

“…The multiple endpoints offer more robust causeeffect relationships than, for instance, surveying biological effects or concentrations of pollutants alone (see Chapman et al 2013). In general, the outline of such strategies ranges from studies involving testing of natural waters ex situ onto surrogate crustaceans, such as Daphnia (Cruzeiro et al 2017) to multi-endpoint Best Professional Judgement approaches to address complex scenarios implicating a wide range of mixed pollutants, multiple estuarine species, in vitro testing and even epidemiology (Caeiro et al 2017). In Table 1, we highlight some of the most representative works that aimed at ERA in estuaries that are either focused on pesticides specifically or include pesticides among a large array of pollutants.…”