天津蔬菜主产区土壤中镉的有效性及关键调控因子研究

Availability and key regulator of cadmium in soil of main vegetable production areas in Tianjin

在天津蔬菜主产区配套采集土壤与农作物样品,运用相关分析和主成分分析等方法对土壤中有效Cd的含量、影响因素及关键调控因子进行研究。结果表明:研究区土壤样品中Cd的含量范围为0.21×10^-6~1.03×10^-6,平均值为0.47×10^-6,超过风险筛选值(GB15618-2018)的比例为28%;有效Cd的含量范围0.05×10^-6~0.48×10^-6,平均值为0.14×10^-6。农作物样品中Cd含量均低于0.05×10^-6,满足食品安全要求(GB2762-2017)。农作物中Cd含量与土壤中Cd含量、有效Cd含量分别呈极显著正相关关系(p<0.01)。土壤有效Cd含量与pH、CEC、黏粒含量呈负相关(p<0.01),与有效P含量呈正相关(p<0.01),而与有机质和Eh没有明显相关性。结合主成分分析及线性回归分析结果可以推断,土壤Cd含量是Cd生物有效性的主控因子。

Soil and crop samples were collected simultaneously from the main vegetable production areas of Tianjin.The concentration of available Cd,influence factors and key regulation factor were studied by correlation analysis and principal component analysis.The results show that the content of Cd in soil samples ranges from 0.21×10^-6 to 1.03×10^-6,with an average of 0.47×10^-6,and the proportion exceeding the risk screening value(GB15618-2018)is 28%.The content of available Cd ranges from 0.05×10^-6 to 0.48×10^-6,with an average of 0.14×10^-6.The Cd content in crop samples is lower than 0.05×10^-6,which meet the food safety requirements(GB2762-2017).The content of Cd in crops is positively correlated with Cd and available Cd in soil(p<0.01).Available Cd content is negatively correlated with pH,CEC and clay content(p<0.01),positively correlated with available P content(p<0.01),but not with organic matter and Eh.Combined with principal component analysis and linear regression analysis,it can be inferred that Cd content is the dominant factor of available Cd in soil.