Table 1.
The average concentrations of toxic elements in the groundwater of Bualda, Fulbaria, Jamjami, and Komlapur, the WHO health-based drinking water guidelines for these toxicants, and the percent of tube wells exceeding these guidelines.
| Element | Average concentration (μg/L) | WHO health-based guideline (μg/L) | Percent of unsafe tube wellsa |
|---|---|---|---|
| As | 29 | 10 | 33 |
| B | < 50 | 500 | 0 |
| Ba | 140 | 700 | 0 |
| Cr | 4.7 | 50 | 1 |
| Fe | 2,700 | NAb | NA |
| Mn | 800 | 400 | 78 |
| Mo | 1.4 | 70 | 0 |
| Ni | 11 | 70 | 1 |
| Pb | 0.5 | 10 | 1 |
| Sb | 1.6 | 20 | 0 |
| Sec | < 1 | 10 | 0 |
| U | 2.5 | 2 | 48 |
| Znc | 15 | NA | NA |
a
Ninety-six percent (64 of 67) of these tube wells are unsafe; that is, only 4% (3 of 67) of these tube wells do not exceed any of these WHO health-based drinking water guidelines.
b
The WHO has not established a health-based drinking water guideline for Fe or Zn (WHO 1996a, 1998a).
c
The severity of chronic As poisoning in Bangladesh might be magnified by a lack of Se or Zn or both (Frisbie et al. 2002; Ortega et al. 2003).