FORMULATION OF SEDIMENTS WITH CHARACTERISTICS OF TROPICAL LOTIC SYSTEMS FOR USE IN ECOTOXICOLOGICAL ASSAYS

Abstract

Investigation of the dynamics and toxicity of pollutants in natural sediments
is hindered by the great complexity of their matrix. Given this difficulty, the
objective of this paper was to recommend the formulation of sediments
representative of tropical lotic environments, considering their use
in ecotoxicological assays. Organic and inorganic fractions were used in
different percentages, resulting in five sediment formulations with different
grain size proportions (fine, medium and coarse sand, and clay). Measured
dissolved oxygen and hardness values were suitable for ecotoxicological
assays; however, regarding pH values, only formulations with lower levels of
organic matter provided suitable water quality for this purpose (between 6.3
and 7.3), for up to 10 days. These formulations were tested using Hyalella
azteca, which confirmed their suitability for use in toxicological tests, since
no lethal effects were observed and there were no significant changes in
terms of growth and reproduction of the organisms.