Biodisponibilidade de Metais-traço em Sedimentos: Uma Revisão

摘要: The chemical association of metal species in sediments provides indications about the release trace metals by processes with toxic effects under certain environmental conditions. knowledge way those are bond to sediments, serves recognize specific sources pollution systems. Speciation plays an important role as far bioavailability and toxicity concerned. accumulation particles occur following mechanisms: a) Adsorption material fine (clay surface); b) precipitation element carbonates, sulfates or oxides; c) co-precipitation iron manganese d) complexation organic matter; e) incorporation into crystal lattice silicates. Currently, five phases considered when studying elements sediments: exchangeable phase, MgCl 2 (causes change salinity); leachable acetic acid pH change); reducible hydroxylamine hydrochloride (allowing anoxic conditions); d ) oxidizable hydrogen peroxide degradation matter); pseudo-residual aqua-regia (allows associated minerals). In last two fractions, strongly bound sediment constituents not available for animals plants. phase is relatively stable nature present therein removed strong oxidizing contained measure degree pollution, since a large amount this indicates lower pollution.