Table 1.
Mn and Ni concentrations in samples of hair and household well water from residents of black shale and reference areas in Sotkamo and Kaavi. Data are only included from households in which both hair samples and water from private well were analysed
| Sotkamo | Water Mn µg/l | Hair Mn mg/kg | Water Ni µg/l | Hair Ni mg/kg |
|---|---|---|---|---|
| Black shale area n = 45 | ||||
| Median | 9.18 | 1.30 | 2.79a | 0.50 |
| Mean ± SD | 93.18 ± 335 | 2.23 ± 2.28 | 4.80 ± 6.51 | 0.96 ± 1.01 |
| Range | 0.28–1620 | 0.20–11.10 | < LQ-24.20 | < LQ-6.00 |
| Reference area n = 17 | ||||
| Median | 7,84b | 1.37b | 1.17a, b | 0.77 |
| Mean ± SD | 65.50 ± 109.65 | 5.73 ± 9.16 | 1.62 ± 1.62 | 1.62 ± 1.99 |
| Range | 0.94–289 | 0.21–36.44 | < LQ-6.17 | < LQ-8.00 |
| Total n = 62 | ||||
| Median | 9.18 | 1.34 | 2.58 | 0.5 |
| Mean ± SD | 85.59 ± 290.53 | 3.19 ± 5.31 | 3.93 ± 5.77 | 1.14 ± 1.36 |
| Range | 0.28–1620 | 0.20–36.44 | < LQ–24.20 | < LQ–8.00 |
| Kaavi | Water Mn µg/l | Hair Mn mg/kg | Water Ni µg/l | Hair Ni mg/kg |
|---|---|---|---|---|
| Black shale area n = 19 | ||||
| Median | 4.48 | 0.91 | 16.00 | 0.89 |
| Mean ± SD | 37.64 ± 110.90 | 1.75 ± 2.05 | 12.91 ± 13.08 | 1.72 ± 2.70 |
| Range | 0.34–487.00 | 0.31–7.20 | 0.16–51.00 | < LQ–12.31 |
| Reference area n = 11 | ||||
| Median | 1.77b | 0.83b | 6.90b | 0.85 |
| Mean ± SD | 15.15 ± 41.89 | 1.56 ± 2.78 | 5.73 ± 2.96 | 1.10 ± 0.65 |
| Range | 0.42–141.00 | 0.25–9.86 | 0.18–9.15 | 0.43–2.58 |
| Total n = 30 | ||||
| Median | 1.94 | 0.90 | 6.90 | 0.87 |
| Mean ± SD | 29.40 ± 91.43 | 1.68 ± 2.31 | 10.28 ± 11.03 | 1.49 ± 2.18 |
| Range | 0.34–487.00 | 0.25–9.86 | 0.16–51.00 | < LQ–12.31 |
SD = standard deviation, LQ = limit of quantification
aMann–Whitney U-test: between black shale and reference areas of Sotkamo; Ni in water, p = 0.012
bMann–Whitney U-test: between reference areas of Sotkamo and Kaavi; Mn in water, p = 0.020; Mn in hair, p = 0.041; Ni in water, p = 0.001