Ecological risk assessment of the Paraíba River estuary (Brazil): Plan for a tier 1 screening phase for the ecotoxicological line of evidence

The knowledge produced in temperate regions is still used today to evaluate environmental problems in the tropics, without taking into consideration environmental differences, such as local conditions, the sensitivity and ecology of species, and exposure routes of contaminants, essential for understanding and determining the fate and toxicity of chemicals. Considering that Environmental Risk Assessment (ERA) studies for tropical systems are scarce and need to be adjusted, the present study aims at contributing to the awareness and development of tropical ecotoxicology. The estuary of the Paraíba River in Northeast Brazil was selected as a model study-case, as it is a large estuary, subjected to a heavy human pressure due to the numerous social, economic and industrial activities. The present study describes the framework for the problem formulation phase of the ERA process; it first includes a detailed integration of the scientific information available on the study area, to then derive the conceptual model, and finally present the analysis plan for the tier 1 screening phase. The latter is designed to be fundamentally supported by the ecotoxicological line of evidence, to ascertain, without delay, where and why there are environmental problems (i.e., adverse biological effects); ecotoxicological tools developed in temperate climates will be optimized to assess water quality in a tropical system. In addition to its intrinsic value for protecting the study area, the results of the present study are expected to provide an important baseline for conducting ERA in similar tropical aquatic systems across the globe.

An ecotoxicological approach can complement the assessment of natural waters from Portuguese reservoirs?

Within the scope of the European Water Framework Directive (WFD), the scientific community recognized clear opportunities to take advantage of the use of ecotoxicological tools in water quality assessments. In this perspective, bioassays and biomarkers were suggested to contribute to the integration of the chemical and biological conditions, and thus to provide an overall insight into the quality of a water body. This study aimed to assess whether current bioassays as feeding rate assays with Daphnia longispina and growth inhibition assays with Lemna minor are suitable to detect potential ecotoxicity, using waters from Portuguese reservoirs. Several sampling sites were defined in reservoirs (Miranda, Pocinho, and Alqueva). The samplings were conducted in autumn of 2018 and spring of 2019. Total chlorophyll, lipid peroxidation, and proline content were also evaluated in L. minor. Results demonstrated that D. longispina showed some sensitivity to water treatments; however, the results were difficult to interpret since no reason or trend can be accurate. All parameters of L. minor did not show sensitivity to detect potential ecotoxicological risks associated with natural water understudy, since no discrimination among the water treatments was recorded. However, biomarkers/bioassays proved to be concordant to each other. Under the conditions evaluated here (reservoirs and sampling periods), the biological responses observed were not consistent, clear, and coherent with the physical-chemical parameters and chemical analyses performed, suggesting that the ecotoxicological tools selected were not sensitive to assess water quality in this type of ecosystems. In this sense, species of different trophic levels are recommended for ecotoxicological analyses due to differences in species sensitivities.

Deep seabed mining and communities: A transdisciplinary approach to ecological risk assessment in the South Pacific

Deep-sea mineral extraction is a fledgling industry whose guiding principles, legislation, protocols, and regulations are still evolving. Responsible management of the industry is difficult when it is not clearly understood what biological and environmental diversity or ecosystem services may be at risk. But the industry's infancy provides an opportunity to address this challenge by stakeholder-led development and implementation of a multidisciplinary risk assessment framework. This article aims to present the findings of a workshop held in New Zealand that hosted stakeholders from a broad range of interests and regions in the South Pacific associated with the deep-sea mineral activity. The outputs provide stakeholder-informed ecological risk assessment approaches for deep-sea mining activities, identifying tools and techniques to improve the relevance of risk assessment of deep seabed mining projects to communities in the South Pacific. Discussions highlighted the importance of trust or respect among stakeholders, valuing the "life force" of the ocean, the importance of scientific data, and the complications associated with defining acceptable change. This research highlighted the need for a holistic transdisciplinary approach that connects science, management, industry, and community, an approach most likely to provide a "social license" to operate. There is also a need to revise traditional risk assessment methods to make them more relevant to stakeholders. The development of ecotoxicological tools and approaches is an example of how existing practices could be improved to better support deep-sea mineral management. A case study is provided that highlights the current challenges within the legislative framework of New Zealand. Integr Environ Assess Manag 2022;18:664-673. © 2021 SETAC.

Ecotoxicological endpoints, are they useful tools to support ecological status assessment in strongly modified water bodies?

Although man-made reservoirs represent an important water supply source in countries where water scarcity has become a problem, little work has been done on the evaluation of their ecological status. Taking this in account, the general aim of this study was to assess the usefulness of ecotoxicological endpoints in the potential ecological status characterization of water reservoirs, with the purpose of their possible integration in evaluation programs developed under the Water Framework Directive (WFD). To achieve this purpose, a group of bioassays were selected to evaluate both water and sediment compartments at the Alqueva reservoir (the biggest from the Iberian Peninsula), with representative species from different taxonomic and functional groups: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna and Heterocypris incongruens. The ecotoxicological assessment showed that sublethal endpoints (e.g., luminescence, growth or reproduction), would be more useful and sensitive to identify toxicity patterns in this type of water body. In general, the results from this ecotoxicological toolbox agreed with the potential ecological status established according to the WFD, which indicates that the bioassays complement the ecological assessment. Furthermore, the use of an ecotoxicological approach can be extremely useful, especially in cases where the biotic indices are difficult to establish, such as in man-made reservoirs. However, when pollutant concentrations are very low, and/or when nutrients and organic matter concentrations are high, the two approaches do not fit, requiring further research to determine which organisms are more sensitive and the best biotic indices to use under those conditions.