Introduction
Materials and methods
Study area
Sampling
Heavy metal analysis
Statistical analyses
Results and discussion
Heavy metal concentrations
Concentration and related statistical parameters | |||||||
---|---|---|---|---|---|---|---|
Element | Zn | Pb | Cu | Cr | V | Ni | Co |
1 | 1229 | 317 | 203 | 111 | 53.0 | 39.9 | 10.3 |
2 | 1198 | 254 | 210 | 181 | 38.6 | 48.3 | 11.7 |
3 | 1738 | 287 | 351 | 100 | 44.1 | 59.2 | 20.4 |
4 | 2058 | 239 | 469 | 105 | 32.7 | 61.0 | 11.6 |
5 | 1747 | 215 | 272 | 101 | 35.2 | 44.3 | 12.5 |
6 | 957 | 225 | 199 | 111 | 46.5 | 32.5 | 10.2 |
7 | 1345 | 397 | 222 | 175 | 48.5 | 38.7 | 13.0 |
8 | 987 | 241 | 195 | 116 | 45.1 | 29.3 | 10.7 |
9 | 1365 | 292 | 204 | 161 | 35.6 | 33.0 | 11.8 |
10 | 1295 | 217 | 234 | 109 | 33.6 | 54.8 | 9.7 |
11 | 978 | 220 | 210 | 97.3 | 50.9 | 49.0 | 10.7 |
12 | 962 | 196 | 236 | 98.1 | 48.0 | 39.9 | 11.5 |
13 | 971 | 184 | 227 | 108 | 57.1 | 44.8 | 10.7 |
14 | 902 | 190 | 213 | 100 | 36.3 | 37.4 | 9.9 |
15 | 830 | 146 | 183 | 93.1 | 36.1 | 50.0 | 9.6 |
16 | 897 | 333 | 180 | 128 | 55.8 | 42.7 | 13.7 |
17 | 420 | 134 | 87.9 | 63.2 | 34.3 | 26.4 | 9.1 |
18 | 1047 | 198 | 260 | 104 | 62.9 | 38.2 | 10.1 |
19 | 801 | 182 | 185 | 101 | 30.5 | 26.6 | 8.3 |
20 | 1146 | 237 | 229 | 114 | 35.3 | 58.8 | 10.8 |
21 | 467 | 221 | 90.6 | 72.9 | 32.5 | 24.1 | 10.0 |
22 | 355 | 125 | 74.8 | 43.1 | 36.4 | 19.6 | 9.7 |
23 | 975 | 198 | 146 | 97.3 | 56.9 | 36.2 | 10.0 |
24 | 974 | 216 | 198 | 138 | 35.5 | 61.6 | 11.8 |
25 | 882 | 199 | 168 | 156 | 33.0 | 55.5 | 11.1 |
26 | 947 | 207 | 202 | 162 | 39.9 | 40.3 | 12.3 |
27 | 1246 | 312 | 186 | 132 | 43.7 | 33.9 | 11.3 |
28 | 1070 | 215 | 246 | 266 | 49.5 | 52.6 | 14.9 |
29 | 1445 | 504 | 240 | 154 | 48.5 | 65.5 | 11.1 |
30 | 709 | 176 | 152 | 89.5 | 39.5 | 31.7 | 11.1 |
31 | 830 | 178 | 206 | 92.9 | 28.2 | 37.7 | 9.0 |
32 | 934 | 200 | 200 | 97.2 | 36.9 | 40.8 | 10.5 |
33 | 666 | 173 | 108 | 74.4 | 36.3 | 26.4 | 10.1 |
34 | 1051 | 325 | 191 | 118 | 38.2 | 33.0 | 11.6 |
35 | 835 | 219 | 192 | 168 | 40.1 | 44.0 | 12.4 |
36 | 591 | 218 | 122 | 96.0 | 52.6 | 32.5 | 12.6 |
Minimum | 355 | 125 | 74.8 | 43.1 | 28.2 | 19.6 | 8.3 |
Maximum | 2058 | 504 | 469 | 266 | 62.9 | 65.5 | 20.4 |
Mean | 1024 | 233 | 203 | 118 | 41.9 | 41.4 | 11.3 |
SD | 358 | 74.4 | 70.6 | 40.5 | 8.8 | 11.7 | 2.1 |
CV (%) | 35.0 | 31.9 | 34.9 | 34.4 | 20.9 | 28.4 | 18.4 |
Reference value CNEMC (1990) | 74.2 | 26.0 | 22.6 | 61.0 | 82.4 | 26.9 | 12.7 |
Reference value Wong et al. (2002) | 50.7 | 29.9 | 14.7 | 51.8 | Nd | 16.5 | 7.1 |
Ratio (mean/reference value) | 13.8 | 9.0 | 9.0 | 1.9 | 0.5 | 1.5 | 0.9 |
Ratio (mean/reference value) | 20.2 | 7.8 | 13.8 | 2.3 | Nd | 2.5 | 1.6 |
Correlation analysis
Co | Cr | Cu | Ni | Pb | V | Zn | |
---|---|---|---|---|---|---|---|
Co | 0.01 | 0.01 | 0.01 | 0.03 | 0.15 | <0.01 | |
Cr | 0.41** | 0.11 | 0.01 | 0.01 | 0.32 | 0.05 | |
Cu | 0.44** | 0.27 | <0.01 | 0.09 | 0.73 | <0.01 | |
Ni | 0.41** | 0.43** | 0.67** | 0.04 | 0.85 | <0.01 | |
Pb | 0.36* | 0.43** | 0.29 | 0.34* | 0.07 | <0.01 | |
V | 0.24 | 0.17 | 0.06 | 0.03 | 0.30 | 0.74 | |
Zn | 0.47** | 0.33* | 0.88** | 0.63** | 0.53** | 0.06 |
Principal-components analysis
Element | Principal component | Communalities | ||
---|---|---|---|---|
1 | 2 | 3 | ||
Co | 0.45 | 0.46 | 0.32 | 0.52 |
Cr | 0.14 | 0.93 | 0.03 | 0.89 |
Cu | 0.95 | 0.07 | 0.05 | 0.92 |
Ni | 0.73 | 0.39 | −0.08 | 0.70 |
Pb | 0.31 | 0.54 | 0.44 | 0.58 |
V | −0.03 | 0.08 | 0.94 | 0.90 |
Zn | 0.92 | 0.20 | 0.11 | 0.89 |
Initial eigenvalues | 3.39 | 1.22 | 0.77 | |
Variance (%) | 48.44 | 17.48 | 11.05 | |
Cumulative variance (%) | 48.44 | 65.92 | 76.97 |