Plants Heavy metal reported Country Permissible limit according to WHO 1996 Reference
Brassica sp., Chenopodium sp., leafy and root vegetables, grains Cu 1.7–12.9 mg/kg Pb 0.13 mg/kg Zn 7.25–24.6 mg/kg Cr 0.08–0.38 mg/kg Pb 0.02–0.013 mg/kg Cu 0.16–0.85 mg/kg Zn India Cd: 0.02 mg/kg Zn: 0.60 mg/kg Cu: 10 mg/kg Pb: 2 mg/kg Ni: 10 mg/kg Rattan et al. (2005)
Grain, maize (Zea mays), green cabbage, Brassica juncea L, radish (Raphanus sativus L), turnip, Brassica napus, spinach, cauliflower, and lettuce Cr 0.08–0.38 mg/kg Pb 0.02–0.013 mg/kg Cu 0.16–0.85 mg/kg Zn 0.16–0.53 mg/kg China Khan et al., 2013
Brassica sp., food grains, and leafy vegetables Cr 0.01–0.19 mg/kg Pb 0.12–0.23 mg/kg Cu 0.15–0.86 mg/kg Zn 0.42–0.95 mg/kg China Liu et al. (2005)
Spinach Cu 0.09 mg/kg Cr 2.9 mg/kg Pb 3.1 mg/kg Zn 10 mg/kg Ni 3.2 mg/kg India Chary et al. (2008)
Amaranthus Cu 1.4 mg/kg Cr 2.4 mg/kg Pb 2.9 mg/kg Cd nil Zn 8 mg/kg India Chary et al. (2008)
Sesame, Chilli, Okra, Jute, Brinjal, Poi, Amaranthus, Colocasia Cowpea, Cauliflower Zn 24.7-39.4 mg/kg Cu 4.8-21.3 mg/kg Pb 66.3-91,9 mg/kg Cd 11.8-16.8 mg/kg Ni 13.4-26.6 mg/kg India Saha et al., 2015