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- Ecotoxicological endpoints, are they useful tools to support ecological status assessment in strongly modified water bodies?Publication . Palma, Patrícia; Ledo, L.; Alvarenga, P.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 tool-box 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. (C) 2015 Elsevier B.V. All rights reserved.
- Recycling organic wastes to agricultural land as a way to improve its quality: A field study to evaluate benefits and risksPublication . Alvarenga, P.; Palma, Patrícia; Mourinha, C.; Farto, M.; Dores, J.; Patanita, M.; Cunha-Queda, C.; Natal-da-Luz, T.; Renaud, M.; Sousa, J. P.A field study was established to assess the effects of a sewage sludge (SS), a mixed municipal solid waste compost (MMSWC) and a compost produced from agricultural wastes (AWC), in a Vertisol, using Lolium multiflorum L The amendments were applied for two consecutive years: 6, 12 and 24 t dry matter ha(-1) for SS, and the amendment doses for MMSWC and AWC were calculated to deliver the same amount of organic matter (OM) per unit area. The amendments had significant beneficial effects on some soil properties (e.g. soil OM, N-Kjeldahl, extractable P and K), and on plant productivity parameters (e.g. biomass yield, chlorophyll, foliar area). For instance, soil OM increased from 0.78% to 1.71, 2.48 and 2.51%, after two consecutive years of application of 24 t dry matter ha(-1) of SS, MMSWC and AWC, respectively, while the plant biomass obtained increased from 7.75 t ha(-1) to 152.41, 78.14 and 29.26 t ha(-1), for the same amendments. On the plant, effects were more pronounced for SS than for both compost applications, a consequence of its higher capacity to provide N to the plant in a readily available form. However, after two years of application, the effects on foil properties were more noticeable for both composts, as their OM is more-resistant to mineralization, which endures their beneficial effects on soil. Cadmium, Cr, Ni and Pb pseudo-total concentrations, were not affected significantly by the application of the organic wastes to soil, in all tested doses, neither their extractability by 0.01 M CaCl2. On the contrary, Cu and Zn pseudo-total concentrations increased significantly in the second year of the experiment, following the application of the higher rate of MMSWC and AWC, although their extractability remained very low (<0.5% of their pseudo-total fraction). Trace elements concentrations in the aboveground plant material were lower than their maximum tolerable levels for cattle, used as an indicator of risk of their entry into the human food chain. Despite these results, it is interesting to note that the SS promoted a significant increase in the foliar concentrations of Cu, Ni and Zn that did not happen in composts application, which can be explained by the reduction of the soil pH, as a consequence of SS degradation in soil. Concluding, if this type of organic wastes were to be used in a single application, the rate could be as high as 12 or even 24 t ha(-1), however, if they are to be applied in an annual basis, the application rates should be lowered to assure their safe application (e.g. to 6 t ha(-1)). Moreover, it is advisable to use more stable and mature organic wastes, which have longer lasting positive effects on soil characteristics. (C) 2017 Elsevier Ltd. All rights reserved.
- Membranes technology used in water treatment: Chemical, microbiological and ecotoxicological analysisPublication . Palma, Patrícia; Fialho, S.; Alvarenga, P.; Santos, C.; Bras, T.; Palma, G.; Cavaco, C.; Gomes, R.; Neves, L. A.The increment of world's Human population, with the consequent demand for water supply, plus the need for sustainable development and the conservation of water resources, highlights the urgency of improving water treatment technologies and management actions.The aim of the present study was to characterize and evaluate the efficiency of nanofiltration (NF90, NF270) and reverse osmosis (SW30) membranes, in improving the quality of three types of waters: irrigation, municipal supply and wastewater. The efficiency of using this technology was assessed by: (i) the study of water permeability and rejection of some chemical parameters, such as total nitrogen, total phosphorus, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), feacal coliforms, nitrates, chlorides, iron and manganese; and (ii) the evaluation of their ecotoxicological effects, through the use of representative species of different taxonomic and functional groups (Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Pseudokirchneriella subcapitata). Results indicated that all three membranes have high rejection percentages for the majority of the studied parameters (>90%). All parameters concentrations in the permeate stream were below the limit values from Portuguese legislation and European Directives. With respect to the ecotoxicological effects, in general, the use of membranes removed the toxicity detected in the initial samples (which exhibited significant toxicity). The SW30 membrane showed a greater efficiency for toxicity removal, comparing with the nanofiltration membranes. Further, among the nanofiltration membranes used, the NF90 promoted a greater decrease in the toxicity of the samples. Thus, treatment with the membranes NF90 and SW30 allowed obtaining waters with high quality and low ecotoxicological potential, without risks for human populations and endangering the environmental balance. (C) 2016 Elsevier B.V. All rights reserved.