Assessing mercury contamiantion in the Amazon
Selective studies on certain types of fish or humans with certain occupations, i.e. piscivorous fish or fishermen,
were excluded. These types of studies do not represent a normal population, but only a selective part of a
population.
Tabel 2:
Mean mercury concentrations in fish from the Madeira and Tapajos River, Brazil.
| Study area |
Mean Hg conc. in fish ( µg/g ) |
Reference |
| Madeira River |
0.39 (n=576) |
Boischio et al., 2000 |
|
0.36 (n= 245) |
Boischio et al., 1995 |
|
0.34 (n= 125) |
Malm et al., 1995a |
| Average |
0.36 (n= 946) |
|
| |
|
|
| Tapajos River |
0.22 (n= 69) |
Lima et al., 2000 |
|
0.29 (n= 181) |
Lebel et al., 1997 |
|
0.38 (n= 65) |
Castilhos et al., 1998 |
| Average |
0.31 (n= 315) |
|
Data summarized in Table 2 show that observed average methylmercury concentrations in fish samples
are similar for the Madeira and the Tapajos River, 0.36 and 0.3 µg/g, respectively.
Generally, over 90% of the mercury present in fish from the Amazon region is methylmercury (Akagi et al. 1994).
Data summarized in Table 3 show that average human hair mercury concentrations in ribeirinhos populations
along the Madeira and the Tapajos River are similar, 14.8 and 13.8 µg/g, respectively (Table 3). Generally, over 90%
of the mercury present in human hair samples of ribeirinhos populations along the Madeira and Tapajos River is
methylmercury (Kehrig et al., 1997). Only humans with no occupational association to gold mining activities were
accounted for.
Tabel 3:
Mean mercury concentrations in human hair from the Madeira and Tapajos River, Brazil.
| Study area |
Mean Hg conc. in hair ( µg/g ) |
Reference |
| Madeira River |
|
|
|
17 (n=237) |
Boischio et al. 1995 |
|
12.6 (n=90) |
Boischio and Henshel, 2000 |
| Average |
14.8 (n=327) |
|
| |
|
|
| Tapajos River |
|
|
|
13.5 (n=98) |
Amorim et al., 2000 |
|
9.0 (n=84) |
Dolbec et al., 2000 |
|
17.5 (n=91) |
Lebel et al. 1998 |
|
17 (n=432) |
Malm et al., 1997 |
|
16.3 (n=136) |
Akagi et al., 1993 |
|
9.2 (n=96) |
Lebel et al., 1997 |
| Average |
13.8 (n= 937) |
|
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