Pollution Evaluation in Soils and Health Risk in Vegetables of Heavy Metals in Surrounding Lanzhou City in Gansu Province, China

Heavy metal (HMs) contamination in soil causes secondary pollution of vegetables and poses a great threat to health. Soil and vegetable samples were collected from eight different districts in the vegetable base of Lanzhou city in Gansu province. The heavy metal (Zn, Cd, Cr, Cu, and Pb) contents were determined using inductively coupled plasma atomic emission spectroscopy. The results suggest that the Cr and Zn contents of soils in the eight plantation bases were much higher than those of the other three metal contents. The metal concentrations showed significant differences among plantation bases and vegetable species, and the mean HM concentrations of vegetable bases exceeded background levels by 1.1~3.0 times. The accumulation of Cu in vegetables was significantly higher than that of other metals. Remarkable differences were found among the vegetables in the uptake abilities of Zn, Cd, Cr, and Cu. From the linear model regression analysis, significant positive relationships were found between the accumulation of HMs in vegetables and soil content. The information found in this work may be used to provide referential strategies and methods to minimize the impact of HMs on human health through the consumption and cultivation of vegetables.