Overview
Yakubu and Yola measured Zn, Mn, cadmium (Cd), chromium (Cr), and lead (Pb) in soil and nearby borehole water around local aluminium-utensil production in Bachirawa, Kano. This is not utensil migration or finished-product occurrence evidence: it is source-attribution evidence for environmental metal loading around informal aluminium-utensil foundry activity.
Key numbers
The study collected three soil samples labeled A, B, and C from local aluminium-utensil production sites and two borehole-water samples labeled D and E from boreholes 50 m away from the project site.
Table 1 reports site A soil at 18 cm depth, in mg/kg:
Table 2 reports site B soil at 18 cm depth, in mg/kg:
| Metal | Site B soil | Control site | MPI | Classification |
|---|---|---|---|---|
| Zn | 10118.44 | 20.124 | 502.8 | Excessive pollution |
| cadmium (Cd) | 0.026 | 0.108 | 0.24 | Moderate contamination |
| chromium (Cr) | 0.636 | 0.100 | 6.36 | Severe pollution |
| Mn | 1809.672 | 10.672 | 169.57 | Excessive pollution |
| lead (Pb) | 42.54 | 3.751 | 11.34 | Very severe pollution |
Table 3 reports site C soil at 18 cm depth, in mg/kg:
| Metal | Site C soil | Control site | MPI | Classification |
|---|---|---|---|---|
| Zn | 1158.132 | 20.266 | 57.15 | Excessive pollution |
| cadmium (Cd) | 0.165 | 0.048 | 3.43 | Moderate pollution |
| chromium (Cr) | 0.832 | 0.131 | 6.35 | Severe pollution |
| Mn | 285.719 | 13.061 | 21.88 | Very severe pollution |
| lead (Pb) | 148.19 | 4.24 | 34.91 | Excessive pollution |
Table 4 reports water-sample concentrations in mg/l and the WHO guideline values printed by the authors:
| Site | Metal | Concentration (mg/l) | WHO guideline (mg/l) |
|---|---|---|---|
| D | Zn | 0.2411 | 3.0 |
| D | Cd | 0.091 | 0.003 |
| D | Cr | 0.015 | 0.05 |
| D | Mn | 0.284 | 0.4 |
| D | Pb | 0.00 | 0.01 |
| E | Zn | 0.4435 | 3.0 |
| E | Cd | 0.123 | 0.003 |
| E | Cr | 0.022 | 0.05 |
| E | Mn | 0.728 | 0.4 |
| E | Pb | 0.08 | 0.01 |
The abstract summarizes soil ranges as Zn 1158.13-11117.80 mg/kg, Mn 285.719-1809.672 mg/kg, Cd 0.026-0.540 mg/kg, Cr 0.498-0.832 mg/kg, and Pb 42.54-285.53 mg/kg. The table value for site A Pb is 285.59 mg/kg, so the table value is used in the table above and the abstract range is treated as rounded or mistyped.
The conclusion states that foundry activities are sources of environmental pollution in Bachirawa foundry market, with soil metal concentrations decreasing in the order Zn > Mn > Pb > Cd > Cr. The authors also state that Cd and Mn in both water samples and Pb in site E water were above the cited permissible limits.
Methods (brief)
Soil samples were dried, ground, sieved through 2 mm mesh, and digested with concentrated HNO3 and 70% HClO4 on a hot plate until the digest turned white. Water samples were acidified with nitric, hydrochloric, and perchloric acid, digested on a hot plate, filtered, and transferred to 100 ml plastic bottles. Metals were measured by atomic absorption spectrophotometer, model AAS 240 FSAA. Pollution index was calculated as the ratio of metal concentration in the site soil to metal concentration in a control soil.
Related evidence
- Source attribution and environmental burden apportionment
- Atmospheric deposition of heavy metals
- Lead
- Cadmium
- Chromium
- Manganese
- Zinc
Update history
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