Samples | Mean (mg/g, n = 3a ) | ||||||
No.b | Sources | f1 | f2 | f3 | f4 | f5 | Totald |
1 | Jiuquan | 3.14c | 0.26 | 0.07 | 0.13 | 0.11 | 3.71 |
2 | Wuwei | 2.76 | 0.22 | 0.05 | 0.11 | 0.09 | 3.23 |
3 | Zhangye | 2.21 | 0.18 | 0.03 | 0.08 | 0.06 | 2.56 |