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- Toxicity abatement of wastewaters from tourism units by constructed wetlandsPublication . Calheiros, Cristina S. C.; Castro, Paula M. L.; Gavina, Ana; Pereira, RuthThe present research intended to investigate the toxicity abatement of domestic wastewater after passing a biosystem composed of a constructed wetland (CW) followed by a pond. The wastewater was generated in a tourism house in a rural and mountainous context and passed through a septic tank before being diverted to a CW followed by a pond. A battery of ecotoxicological tests, comprising microalgae (Raphidocelis subcapitata), macrophytes (Lemna minor), cladocerans (Daphnia magna), and bacteria (Aliivibrio fischeri), was used to assess the toxicity of the wastewater collected before and after the CW and the water of the pond. Physicochemical parameters (pH, conductivity, chemical oxygen demand, biochemical oxygen demand, total suspended solids, phosphates, ammonium, and nitrate) were also determined. The CW was able to remove carbon and nutrients from the water with a concomitant reduction of its toxicity. This study, reinforced the added value of using toxicity tests as a complement to CW operational monitoring to validate the solution and to analyze possible readjustments that may be required to improve efficiency. This study lends further support to the claim that CWs can be a sustainable solution for treating small volumes of domestic wastewater in a rural context.
- Review of the ecotoxicological effects of emerging contaminants to soil biotaPublication . Gomes, Ana R.; Justino, Celine; Rocha-Santos, Teresa; Freitas, Ana C.; Duarte, Armando C.; Pereira, RuthIn recent years, emerging contaminants (e.g. pesticides and their metabolites, pharmaceuticals, personal and house care products, life-style compounds, food additives, industrial products and wastes, as well as nanomaterials) have become a problem to the environment. In fact, the cumulative use of a panoply of chemical substances in agriculture, industrial activities, in our homes and in health care services has led to their recent appearance in detectable levels in soils, surface, and groundwater resources, with unpredictable consequences for these ecosystems. Few data exist regarding the toxicity and potential for bioaccumulation in biota. When available, data were obtained only for some representatives of the main groups of chemical substances, and for a limited number of species, following non-standard protocols. This makes difficult the calculation of predicted no effect concentrations (PNEC) and the existence of sufficient data to set limits for their release into the environment. This is particularly concerning for the soil compartment, since only recently the scientific community, regulators, and the public have realised the importance of protecting this natural resource and its services to guarantee the sustainability of terrestrial ecosystems and human well-being. In this context, this review paper aims to identify the major groups of soil emerging contaminants, their sources, pathways and receptors, and in parallel to analyse existing ecotoxicological data for soil biota.
- Effects of dietary exposure to herbicide and of the nutritive quality of contaminated food on the reproductive output of Daphnia magnaPublication . Silva, M. Bessa da; Abrantes, N.; Rocha-Santos, T.A.P.; Duarte, A.C.; Freitas, A.C.; Gomes, Ana M. P.; Carvalho, A.P.; Marques, J.C.; Gonçalves, F.; Pereira, R.tRisk assessment of pesticides has been based on direct toxic effects on aquatic organisms. Indirect effectsdata are taken into account but with limitations, as it is frequently difficult to predict their real impactsin the ecosystems. In this context the main aim of this work was to assess how the exposure to theherbicide pendimethalin (Prowl®), under environmentally relevant concentrations, may compromise thenutritional composition of food for a relevant group of primary consumers of freshwater food webs—thedaphnids, thus affecting their reproduction performance and subsequently the long-term sustainabilityof active populations of this grazer. Therefore, Daphnia magna individuals were chronically exposed in aclean medium to a control diet (NCF – i.e., non-contaminated green algae Raphidocelis subcapitata) and to acontaminated diet (CF – i.e., the same monoalgal culture grown in a medium enriched with pendimethalinin a concentration equivalent to the EC20for growth inhibition of algae), during which reproductiveendpoints were assessed. The algae were analysed for protein, carbohydrate and fatty acid content. Thechemical composition of R. subcapitata in the CF revealed a slight decrease on total fatty acid levels, witha particular decrease of essential 9 monounsaturated fatty acids. In contrast, the protein content washigh in the CF. D. magna exposed to CF experienced a 16% reduction in reproduction, measured as thetotal number of offspring produced per female. Additionally, an internal pendimethalin body burden of4.226 g g−1was accumulated by daphnids fed with CF. Hence, although it is difficult to discriminate thecontribution of the pesticide (as a toxic agent transferred through the food web) from that of the food witha poor quality—compromised by the same pesticide, there are no doubts that, under environmentallyrelevant concentrations of pesticides, both pathways may compromise the populations of freshwatergrazers in the long term, with consequences in the control of the primary productivity of these systems.