科研之友
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摘要
mercury levels assessment in aquatic systems areas without influences of antropogenic sources have not been well studied in the amazon region. for the identification of the origin of high values of hg in fish consumed by population of rio branco city - ac, the evandro chagas institute - iec, studied the mercury levels in sediments, suspended solids and studied also the physical-chemical characterization of waters, in the acre river and also some in afluents, between brasil谷ia and assis brasil cities. bottom sediments samples were sieved to %26lt;250 mesh fraction after drying. the suspended solid was obtained by precipitation with al2so4. about 250 mg of the material was submitted the acid digestion and the determinations of hg were made by could vapor atomic absorption spectrometry. the physical-chemical parameters ph, electric conductivity, temperature and dissolved total solids, were studied in the field, by potenciometric methods. the hg levels in bottom sediments range 0,018 and 0,184 mg g-1, mean of 0,054 ㊣ 0,034 mg g-1, while the suspended solids varied between 0,067 and 0,220 mg g-1, average of 0,098 ㊣ 0,037 mg g-1. the waters were slightly acid with ph varying among 5,80 - 6,95 and conductivity electric 151,60 - 1.151,00 ms cm-1. the mercury levels in the analyzed materials was below of standard levels for the non-polluted amazon rivers. however complementary studies should be developed to elucidate the origin and the processes of mercury biodisponibility.
