黄河三角洲农田土壤-作物系统重金属污染风险评估

重金属严重影响着农业用地土壤环境质量以及农产品安全,已引起国内外广泛关注. 本研究以我国重要的粮 食产区黄河三角洲典型农田为对象,评估了农田土壤-作物系统中重金属的污染风险. 研究结果表明,黄河三角洲农田 土壤中重金属 Cr、Cu和 Pb的质量分数具有显著性差异(P<0.05), Cr的质量分数(47.20mg·kg-1)最高, Cu(26.00 mg·kg-1)次之,而 Pb(13.90mg·kg-1)最低,各重金属分布存在中等的空间异质性. 根据单因子污染指数和内梅罗综合 污染指数,黄河三角洲农田土壤总体上处于清洁水平,重金属污染风险较低,但不同作物区具有显著性差异(P<0.05). 小麦田和水稻田土壤 Cr、Cu的质量分数显著高于藕池和玉米田,小麦田和水稻田土壤 Pb的质量分数与藕池差异不显 著,但显著高于玉米田.3种重金属元素在各主要农作物的地上部分均呈现一定程度的富集,且 Cu的富集程度最高,Pb 的富集程度最低;不同作物对重金属元素的富集程度不同,对 Cr的富集程度由高到低呈现为玉米、藕叶、水稻、小麦,对 Cu的富集程度由高到低呈现为玉米、水稻、藕叶、小麦,而对 Pb的富集程度由高到低呈现为水稻、玉米、小麦、藕叶. 

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 concentrations of heavy metals Cr,Cu,Pb.Concentrations of three heavy metals were significantly different and showed medium spatial variations.Cr (47.20 mg·kg-1 )showed the highest concentration,followed by Cu (26.00 mg·kg-1 )and Pb (13.90 mg·kg-1 ).Heavy metal pollution indexes in soils of wheat and paddy fields were significantly higher than those in maize fields and in lotus sediments.All indexes were found to be below 0.7,showing that heavy metal pollution was 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 differences were found between the other two metals.Bio-concentration factors in different crops were different.Maize showed the highest absorption of Cr and Cu,and rice had the highest ability to absorb Pb.These findings provide valuable information for sustainable agriculture in the Yellow River Delta.