RESUMO
Chemical and toxicological crude oil analysis was performed on water-accommodated fraction of oil (WAF). This study characterized the chemical composition of WAF and its dissipation over a period of 192â¯h. Acute (96â¯h) and chronic (14â¯d) toxicity of WAF were evaluated on Hyalella curvispina from both reference (Los Barreales lake, LB) and hydrocarbon-contaminated (Durán stream, DS) sites. The total hydrocarbon (TPHs) concentration in WAF was 2.18â¯mgâ¯L-1. The dissipation rates of hydrocarbons in WAF showed a first-order kinetics, with half-lives ranging between 65â¯h-200â¯h. Amphipods from LB showed acute and chronic LC50 values of 0.33 and 0.018â¯mgâ¯L-1, respectively. Amphipods from DS exposed to pure WAF showed no mortality in either acute or chronic assays. Further biochemical and molecular research is required to determine the mechanisms underlying the resistance to WAF exposure on DS amphipods.