Table 3 Statistical analysis of eight trace elements in three crops. The different capital letters after the Mean values indicate a significant difference (p < 0.05) in trace element content or soil properties among the three farmlands using One-way ANOVA, whereas same capital letters show no significant differences (p > 0.05). Risk Control Standard (RCS) is regulated by the China Health Ministry (supporting information Table S7).
Farmlands | Trace elements | Min (mg kg−1) | Max (mg kg−1) | Mean (mg kg−1) | RCS | SD (mg kg−1) | Exceedance rate (%) |
|---|---|---|---|---|---|---|---|
Grain N = 63 | As | < 0.01 | 0.08 | 1.78 × 10–2 A | ≤ 0.70 | 1.48 × 10–2 | 0.00 |
Cd | < 0.001 | 0.02 | 3.17 × 10–3 A | ≤ 0.05 | 4.42 × 10–3 | 0.00 | |
Cr | 0.03 | 1.98 | 0.37 B | ≤ 1.00 | 0.34 | 4.76 | |
Cu | 0.52 | 2.39 | 1.48 A | ≤ 10.00 | 0.32 | 0.00 | |
Hg | < 0.003 | 0.01 | 2.13 × 10–3 A | ≤ 0.02 | 2.92 × 10–3 | 0.00 | |
Ni | < 0.05 | 0.05 | 0.03 × 10–2 B | ≤ 0.40 | 0.01 | 0.00 | |
Pb | < 0.02 | 0.20 | 4.01 × 10–2 B | ≤ 0.40 | 4.81 × 10–2 | 0.00 | |
Zn | 0.73 | 15.80 | 10.21 A | ≤ 50.00 | 4.10 | 0.00 | |
Melon and fruits N = 135 | As | < 0.01 | 0.15 | 1.68 × 10–2 A | ≤ 0.50 | 1.94 × 10–2 | 0.00 |
Cd | < 0.001 | 0.07 | 4.03 × 10–3 A | ≤ 0.03 | 8.67 × 10–3 | 2.22 | |
Cr | < 0.05 | 3.44 | 0.26 B | ≤ 0.50 | 0.34 | 11.11 | |
Cu | < 0.20 | 3.47 | 1.06 A | ≤ 10.00 | 0.53 | 0.00 | |
Hg | < 0.003 | 0.01 | 1.50 × 10–3 A | ≤ 0.01 | 2.23 × 10–3 | 0.00 | |
Ni | < 0.05 | 0.33 | 0.02 A | ≤ 0.40 | 0.06 | 0.00 | |
Pb | < 0.02 | 0.18 | 0.06 AB | ≤ 0.20 | 0.04 | 0.00 | |
Zn | 0.23 | 6.12 | 1.36 C | ≤ 5.00 | 1.08 | 1.48 | |
Vegetables n = 337 | As | < 0.01 | 0.31 | 0.02 A | ≤ 0.50 | 0.03 | 0.00 |
Cd | < 0.001 | 0.04 | 8.33 × 10–3 B | ≤ 0.05 | 7.56 × 10–3 | 0.00 | |
Cr | < 0.20 | 0.73 | 0.09 A | ≤ 0.50 | 0.08 | 1.18 | |
Cu | < 0.003 | 3.22 | 0.94 A | ≤ 10.00 | 0.56 | 0.00 | |
Hg | < 0.05 | 0.64*10–2 | 1.76 × 10–4 B | ≤ 0.01 | 0.85 × 10–4 | 0.00 | |
Ni | < 0.02 | 0.15 | 2.84 × 10–2 B | ≤ 0.40 | 1.71 × 10–2 | 0.00 | |
Pb | < 0.02 | 0.26 | 0.06 A | ≤ 0.20 | 0.04 | 0.89 | |
Zn | 0.49 | 8.37 | 2.99 B | ≤ 20.00 | 1.31 | 0.00 |
