Assessment of the heavy metal pollution risks in soil-crop systems of farmlands in the Yellow River Delta

Heavymetal pollution threatens the quality and quantity of agricultural products worldwide, especially with rapid economic development and population growth. We collected topsoil samples and aboveground crops from farmlands in the Yellow River Delta to measure their content of heavy metals Cr, Cu, Pb. Soil heavy metal contents were found to be significantly different in medium spatial variations. Cr (4720 mg〖DK〗·kg-1) showed the highest concentration, followed by Cu (2600 mg〖DK〗·kg-1) and Pb (1390 mg〖DK〗·kg-1). Heavymetal pollution indexes in soils of wheat and paddy fields were significantly higher than in maize fields and in lotus sediments. All indexes were found to be below 07, the concentrations of heavy metals Cr, Cu, Pb were therefore in a clean status. These metals more or less all accumulated in aboveground parts of crops. Bioconcentration factor of Cu was the highest, but no significant variations were found for the other two metals. Bioconcentration factors in different crops were different. Maize showed the highest adsorption of Cr and Cu, rice the highest ability to absorb Pb. These data provide valuable information for sustainable agriculture in the Yellow River Delta.