ASPECTOS DA BIOGEOQUIMICA DO MERCÚRIO EM LAGOS NA PLANICIE COSTEIRA DO SUL DO RIO GRANDE DO SUL
Mercury is one of the most hazardous contaminant in aquatic environment. Mercury contamination in aquatic environment food webs can be severe and persistent, and fish are a major source of mercury contamination in humans across food web. In this study:- Was measured mercury levels at three lakes in southern Brazil and assessed relationships between mercury in atmospheric precipitation, particulate matter in lake water, sediment, soil near the lake, groundwater, aquatic plants, aquatic mollusc and fish tissues at sites close to (industrial and suburban areas) and distant from (protected conservation area) sources of mercury emissions.- Mercury levels are measured in twenty-seven fish species from four sites (close lake, open lake, estuary, marine).- Was simulated the input of mercury at atmosphere from lake, through the experiment. In this experiment to add the dust contamination with mercury in pools contained: fish, sediments and aquatic plants.Also assessed relationship between mercury in fish species and their trophic habits. Mercury concentrations in sediment and aquatic plants did not significant variation among lakes. In aquatic mollusc, groundwater and particulate matter in lake water has small difference between the three sites. In contrast, mercury in precipitation at the study lakes increased with proximity to industrial sources. Mercury in fish tissue generally increased along the same gradient, but also variedXIIIwith trophic level. Atmospheric mercury deposition to these closed lakes may be directly linked to concentrations in fish.Was finding the highest mercury concentration in fish from close lake in relation than open lake, estuary and ocean. In every site the piscivorous species present more mercury in tissue than species non-piscivorous.The simulation of process of mercury contamination through the deposition of atmospheric precipitation in the water surface in laboratory demonstrates progressive mercury accumulation in aquatic plants and sediment.
Advisor:Paulo Roberto Martins Baisch; Isabel Cristina Sobreira Machado; Arí Roisenberg; Nicolai Mirlean
School:Fundação Universidade Federal do Rio Grande
Source Type:Master's Thesis
Date of Publication:03/16/2006