Ecotoxicological assessment of the potential impact on soil porewater, surface and groundwater from the use of organic wastes as soil amendments

This study aimed to assess the potential impact on soil porewater, surface and groundwater from the beneficial application of organic wastes to soil, using their eluates and acute bioassays with aquatic organisms and plants: luminescence inhibition of Vibrio fischeri (15 and 30 min), Daphnia magna immobilization (48 h), Thamnocephalus platyurus survival (24 h), and seed germination of Lolium perenne (7 d) and Lactuca sativa (5 d). Some organic wastes' eluates promoted high toxic responses, but that toxicity could not be predicted by their chemical characterization, which is compulsory by regulatory documents. In fact, when organisms were exposed to the water-extractable chemical compounds of the organic wastes, the toxic responses were mare connected to the degree of stabilization of the organic wastes, or to the treatment used to achieve that stabilization, than to their contaminant load. That is why the environmental risk assessment of the use of organic wastes as soil amendments should integrate bioassays with eluates, in order to correctly evaluate the effects of the most bioavailable fraction of all the chemical compounds, which can be difficult to predict from the characterization required in regulatory documents. According to our results, some rapid and standardized acute bioassays can be suggested to integrate a Tier 1 ecotoxicological evaluation of organic wastes with potential to be land applied, namely luminescence inhibition of V fischeri, D. magna immobilization, and the germination of L. perenne and L sativa

Membranes technology used in water treatment: Chemical, microbiological and ecotoxicological analysis

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