Lead in paddy soils and rice plants Lechang and its potential health risk around lead/zinc Mine, Guangdong, China

As part of a project on phytoextraction of lead (Ph) in paddy soils around a lead/zinc (Pb/Zn) Mine in Lechang of Guangdong Province, South China, the concentration distribution of Ph in paddy soil-rice system was investigated, and its potential health risk to animal/human was evaluated. Total and diethylenetetraminepentaacetic acid (DTPA)-extractable Ph in soils averaged 1486 and 268 mug/g, respectively. According to sequential extraction procedure, soil Ph occurred primarily in the residual, carbonate and exchangeable fractions (30.2%, 26.7% and 19.1%, respectively). Lead extracted by the gastric juice simulation test (GJST) was 1068 mug/g and accounted for 75.4% of the total concentration. Mean Ph concentrations of 419 mug/g in rice root, 69.1 mug/g in whole straw, 51.0 mug/g in part straw (without two leaves near above the root), 44.9 mug/g in stalk, 21.9 mug/g in hull, 13.2 mug/g in grain with hull and 4.67 mug/g in grain without hull (namely, unpolished rice) were found. Lead concentrations in both soil and rice plant were far above the corresponding tolerable levels. Lead daily intakes by local residents were 2.6 mg for adults and 1.2 mg for children, which were much higher than the allowable level. Thus, Pb in this area might pose a potential health risk to the local population. (C) 2004 Elsevier Ltd. All rights reserved.