Distribution and Evaluation of Nutrient and Cd/Pb Content in Agricultural Soils in Huize Lead-Zinc Mine Area

PurposeTo investigate the distribution and pollution evaluation of cadmium (Cd) and lead (Pb), and to explore the correlation between nutrient and heavy metal forms in agricultural soil in Huize lead-zinc mine area.

MethodWe collected 0-60 cm soil and analyzed the Cd and Pb and soil nutrient content. The risks of Cd and Pb were evaluated using the single factor index evaluation method and Nemerow integrated index method and potential ecological risk index proposed by Hakanson.

Result(1) 0-20 cm soil has seriously Cd and Pb pollution than other depth. The pollution of Cd has achieved the high levels (P_i, P_N>3). The pollution of Pb were high levels (P_i, P_N>3) and safety scope (P_N<0.7) pollution in adjacent and far away mine sampling points of agricultural soil, respectively. There were high potential ecological risk of Cd pollution (E_i>110) and safe range of ecological risk for Pb pollution (E_i<55) in all soils. (2) Cd and Pb mainly existed as residual fraction and proportion for 52.54% and 50.26%. The potential bio-available of Pb in all soils and the potential bio-available of Cd in adjacent mine sampling points of agricultural soil were higher than 44%. (3) Agricultural soil had a low nutrient level in mine area. The nutrient content of adjacent mine sampling points of agricultural soil were higher than far away sampling points. Total and exchangeable Cd and Pb contents had the negative correlation with the total and available phosphorus content (P<0.05 or P<0.01).

ConclusionThe pollution and ecological risk of Cd were higher than Pb and it was significant correlation between Cd, Pb and phosphorus.