Table 5.
Showing the mean ± SE levels (ppm) of heavy metals (Hg, Pb, Cr, Cd, Tl, and Ni) for soil samples collected in triplicates (except at site B) from eight different sites in Nairobi industrial area, Kenya.
| Site of samples collection | Samples codes | Heavy metals analyzed (ppm or ppb) | |||||
|---|---|---|---|---|---|---|---|
| Hg (5)a | Pb (0.01) | Cr (0.5) | Cd (0.01) | Tl (0.02) | Ni (0.1) | ||
| Tetrapak | A1, A2, A3 | 52.33 ± 4.33 | 118.28 ± 9.46 | 22.40 ± 2.09 | 0.61 ± 0.07 | 0.34 ± 0.01 | 15.50 ± 0.64 |
| Chief’s Camp | B1, B2, B3, B4 | 223.75 ± 63.90 | 255.50 ± 91.20 | 31.68 ± 11.11 | 1.90 ± 1.40 | 0.50 ± 0.06 | 17.03 ± 3.61 |
| Railways Lower | C1, C2, C3 | 121.00 ± 8.26 | 211.00 ± 8.26 | 81.17 ± 3.80 | 1.03 ± 0.05 | 0.35 ± 0.02 | 26.53 ± 0.77 |
| Railways Upper | D1, D2, D3 | 75.00 ± 25.03 | 165.96 ± 7.14 | 67.83 ± 6.66 | 1.58 ± 0.82 | 0.43 ± 0.01 | 29.87 ± 1.90 |
| Davis & Shirtliff | E1, E2, E3 | 106.67 ± 8.25 | 471.17 ± 117.5 | 72.80 ± 23.36 | 0.82 ± 0.05 | 0.47 ± 0.02 | 17.50 ± 0.26 |
| Kartasi | F1, F2, F3 | 56.33 ± 12.20 | 174.48 ± 8.48 | 36.70 ± 3.37 | 0.53 ± 0.08 | 0.31 ± 0.01 | 16.30 ± 0.67 |
| Sinai | G1, G2 G3 | 23.67 ± 3.38 | 59.92 ± 8.42 | 27.63 ± 5.55 | 0.31 ± 0.01 | 0.43 ± 0.06 | 16.07 ± 0.07 |
| Donholm | H1, H2, H3 | 26.00 ± 2.31 | 143.56 ± 62.17 | 21.37 ± 9.87 | 0.20 ± 0.05 | 0.23 ± 0.01 | 11.70 ± 0.44 |
| Mean concentration (ppm) | 85.59 ± 23.24b | 199.99 ± 43.92 | 45.19 ± 8.68 | 0.87 ± 0.21 | 0.38 ± 0.03 | 18.81 ± 2.16 | |
aThe value in bracket shows the method detection limit (MDL). All the units were ppm except for Hg which was in ppb; bThe mean concentration for Hg is in ppb units.