Comparative study on heavy metal pollution by croplands and crops around a pyrite area and a sulfuric acid factory in Guangdong

This study was designed to comparatively investigate the contamination levels of heavy metal Tl, Pb, Cu and Ni in the crops (Soybean, Taro, Zea mays L. and Arachis hypogaea) grown in the vicinity of pyrite area and sulfuric acid plant in Guangdong Province, China.The results showed that soils in the cropland nearby the pyrite mining area and sulfuric acid plant using pyrite as raw material were contaminated by Tl and Pb, with the concentrations of 2.35~5.03 mg/kg and 43.2~177.1 mg/kg, respectively. The concentrations of Tl in the 4 kinds of studied crops grown on the cropland near the sulfuric acid plant were generally higher than the corresponding crops elsewhere. The fruits of Soybean and Taro had higher concentration of Tl (1.15~4.08 mg/kg) than the German safe limit for food (0.5mg/kg), and the Pb concentration in the Soybean fruit exceeded the China safe limit for food, endangering the health of local people. The bio-accumulation factor of Tl decreased in the order of Soybean, Taro, Zea mays L. and Arachis hypogaea. The Taro, Zea mays L. and Arachis hypogaea grown on the cropland near the sulfuric acid plant respectively displayed relatively strong accumulation capacity of Pb, Cu and Ni.