Bioacumulação de mercúrio em populações ribeirinhas da bacia do Rio Negro, AM - Brasil: influência de fatores ambientais, biológicos e temporais.
Human populations that inhabit the banks of Amazonian rivers and lakes use fish as their main protein source and are, consequently, vulnerable to mercury contamination. Due to the sedentary nature of these populations, their hair average hair mercury concentrations provide a good bioindicator for in...
| Autor principal: | Balassa, Graziela Custodio |
|---|---|
| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Biologia de Água Doce e Pesca Interior - BADPI
2020
|
| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/13017 http://lattes.cnpq.br/7388483643960735 |
| Resumo: |
|---|
|
Human populations that inhabit the banks of Amazonian rivers and lakes use fish as their main protein source and are, consequently, vulnerable to mercury contamination. Due to the sedentary nature of these populations, their hair average hair mercury concentrations provide a good bioindicator for investigating the effects of local and regional environmental variation on human mercury contamination. The aim of this study was to investigate the influence of pH, dissolved organic carbon (DOC) and the relative availability of potential methylation sites (floodplain forests and hydromorphic soils) on the concentration of total mercury (THg) in the hair of fish-eating human populations of the Negro river basin, Brazilian Amazon. Relations
with weight, age, gender and aspects of the consumption of fish were also investigated. In addition, a temporal analysis of the levels of THg was assessed by sequential analysis of 12 cm from the hair of one woman from each community. A total of 50 hair samples were collected from people living in 14 riverside communities. Samples for DOC were collected and pH was measured in the tributaries where these communities fished. The percentage of alluvial floodplains and hydromorphic soils (potential methylation site) in the drainage basin upstream from each sampling point was estimated from radar images and existing soil maps with GIS. The concentration of THg in hair ranged from 3.14 to 58.35 μg/g (mean = 23.92, standard deviation ±14.58) and was not affected by weight, by age or gender of the individuals. Environmental factors analyzed explained about half the variation in THg found in riparian population (r² = 0.50), with most of this variance explained by pH and DOC. Better results may be obtained with collections done in different periods of the annual hydrological cycle. The temporal evaluation showed that there are significant differences in the
concentration of THg in hair different sequences (ANOVA: F11,99 = 2,1244; p = 0,025), where the months of November through May showed the highest levels of contamination and the months June to October values lower. The frequency of consumption of herbivorous fish was higher during the dry season and piscivorous/carnivores fish during the drought, indicating that diet and concentration of THg change throughout the hydrological cycle. |