Mercury concentration in fish from the Upper Madeira River, Brazil -- 1991 and 1993
- Indiana Univ., Bloomington, IN (United States). School of Public and Environmental Affairs
- Univ. of Brasilia, Federal District (Brazil). Chemistry Dept.
The informal small-scale gold mining in the Amazon releases metallic mercury (Hg{sup 0}) into the aquatic and atmospheric ecosystems. Metallic Hg is oxidized and the resultant divalent Hg (Hg{sup 2+}) is organified to methyl Hg (MeHg). The MeHg is bioaccumulated in the aquatic food chain. Fish is the major route of MeHg exposure for humans. The authors have been studying the Hg concentration in food fish from approximately 590 fish samples collected in 1991 and 1993 from the Upper Madeira river, downstream from an intense gold mining area. These samples include 40 species, covering 5 trophic levels. Their data indicate that the study food chain is unevenly contaminated. The mean Hg concentration ranged from 0.1 {micro}g/g ({+-} 0.1) among herbivorous species (n = 82) to 0.6 {micro}g/g ({+-} 0.5) among piscivorous species (n = 230), with a total population low of non detectable and a high of 11.2 {micro}g/g in one omnivorous specimen. Their results indicate that Hg biomagnification is probably occurring in the study food chain, although the trophic categories are very flexible for most of the fish species in the Amazonian ecosystems. This flexibility in the fish diet might explain the wide variation in fish Hg concentration observed in this study, Other relevant factors for fish Hg concentration are the body weight, the migration pattern of fish and fish prey, and the habitat from which these specimens were collected (main channels, lakes and streams).
- OSTI ID:
- 242383
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9626%%211
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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