Avaliação ecotoxicológica do biossólido produzido na ETE/CEDAE/Ilha do Governador-RJ

Abstract

The production of sludge created by domestic residues tends to grow mainly in developing countries, whre there is the expectation of an increase in basic sanitation. This residue when treated adequately, that is turned into biosolid and used in agriculture, shows as an economic practice as well as environmentally appropriate manner to final destination. Ecotoxicological essays are an important tool to evaluate the biosolid safety usage by living organisms. Therefore, essays on soil microbiota, algae, cladocerans, fish, and also earthworms, springtails (Collembola) and Enchytraeids in natural soils (Planosol and Ultisol), treated with different concentrations of biosolid produced at ETE/CEDAE/Ilha do Governador-RJ, were performed. The soil microbiota was the less sensitive to the residue use, in growing and in the metabolism. In aquatic environment, algae (Raphidoceles subcapitata) showed higher sensitivity with 12,7% e 8,87% EC50, followed by cladocerans (Daphnia magna) with 32,0% and 17,9% EC50 and fish (Danio rerio) with 42,7% and 38,9% LC50, in a Planosol and Ultisol respectively. Lettuce seeds (Lactuca sativa) showed a 50% reduction in germination in 36,1% (in Planosol) and 29,5% (in Ultisol) concentration of biosolid. Escape and reproduction tests on earth invertebrates were performed, escape results showing 33,8% and 33,5% EC50 for Collembola and 48,03% and 33,82% for earthworms, being Folsomia candida organisms more sensitive than the earthworms, while reproduction essays showed 20,8% EC50 in both types of soilfor Collembola and 22,82% and 20,77% for Enchytraeids, in Planosol and Ultisol. Concentrations that cause damage are higher than those used as fertilizer. One should, though, pay attention to the treatment periodicity, the use of biosolid as substrate and its storage, to prevent it from reaching hydric resources.