Table 3 Descriptive statistics of soil HMs in the study area.
Element | Maximum value | Minimum value | Mean value | Median | Standard deviation | Coefficient of variation/% | Enrichment coefficient | Lhasa background value | Screening value (agricultural land) | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
A | B | C | D | |||||||||
Cu(mg·kg− 1) | 85.0 | 12.5 | 24.6 | 24.1 | 5.55 | 22.5 | 1.12 | 22 | 50 | 50 | 100 | 100 |
Pb(mg·kg− 1) | 126 | 17.3 | 31.4 | 30.4 | 7.93 | 25.2 | 1.01 | 31 | 70 | 90 | 120 | 170 |
Zn(mg·kg− 1) | 339 | 46.3 | 80.6 | 77.7 | 21.0 | 26.1 | 1.24 | 65 | 200 | 200 | 250 | 300 |
Cr(mg·kg− 1) | 135 | 19.4 | 57.7 | 58.2 | 12.8 | 22.2 | 1.37 | 42 | 150 | 150 | 200 | 250 |
Ni(mg·kg− 1) | 46.8 | 10.1 | 25.7 | 25.8 | 5.47 | 21.3 | 1.22 | 21 | 60 | 70 | 100 | 190 |
Cd(mg·kg− 1) | 0.998 | 0.054 | 0.17 | 0.16 | 0.08 | 48.0 | 1.44 | 0.12 | 0.3 | 0.3 | 0.3 | 0.6 |
As(mg·kg− 1) | 55.5 | 4.42 | 21.6 | 20.0 | 8.26 | 38.3 | 1.08 | 20 | 40 | 40 | 30 | 25 |
pH | 8.86 | 4.83 | 7.71 | 7.95 | 40.75 | 9.74 | 0.94 | 8.2 | – | – | – | – |
TN(g·kg− 1) | 0.19 | 7.39 | 1.27 | 1.28 | 0.58 | 46.2 | – | – | – | – | – | – |
TP(g·kg− 1) | 0.29 | 1.66 | 0.67 | 0.64 | 0.19 | 28.6 | – | – | – | – | – | – |
TK(g·kg− 1) | 13.7 | 33.8 | 23.0 | 22.7 | 2.61 | 11.4 | – | – | – | – | – | – |
SOM(g·kg− 1) | 2.76 | 146 | 20.0 | 19.5 | 11.8 | 59.2 | – | – | – | – | – | – |
Sc(mg·kg− 1) | 23.3 | 7.32 | 12.3 | 12.2 | 1.47 | 12.0 |  |  |  |  |  |  |
