湖北省地质高背景地区水稻-镉的耕地安全生产阈值研究

Study on rice-Cadmium of safety production threshold of cultivated land in high geological background area of Hubei province

地质高背景地区土壤Cd超标与水稻超标不一致,需要筛选适合地质高背景地区水稻-镉耕地安全生产阈值。研究通过对土壤-水稻重金属、理化指标的相关性进行分析,通过空间插值及参数计算,结果表明,土壤中Cd含量与土壤主要理化指标(pH、有机质、阳离子交换量)的线性关系较弱,说明地质高背景地区由于土壤本底值等因素,土壤自污染程度较严重。水稻Cd与土壤理化指标之间关系紧密,可能是因为地质高背景地区重金属背景值较高,但未受人类活动影响,对所种植水稻的Cd含量影响不大。通过计算所需参数和插值,初步判断该地质高背景区耕地安全阈值为0.31 mg/kg。对预测结果的合理性进行检验,结果表明该地质高背景区耕地安全阈值设定合理。

It is inconsistent to exceed the Cd standard in the high geological background area and the Cd standard in the rice area,so the safe production threshold of rice-cadmium cultivated land suitable for the high geological background area should be selected.This study based on the soil heavy metals-rice,physical and chemical means of correlation analysis,through spatial interpolation and pa⁃rameter calculation,get the following results,Cd content in soil and soil physical and chemical indicators(pH,organic matter,cation exchange capacity)is weak,the linear relationship between the regions with high explain geological background due to factors such as soil background value,the soil pollution is serious.There is a close relationship between Cd in rice and soil physicochemical proper⁃ties,which may be because although the background value of heavy metals in high geological background is high,it is not affected by human activities and has little impact on Cd content of rice planted.By calculating the required parameters and interpolation,the culti⁃vated land safety threshold of the geological high background area was preliminarily judged to be 0.31 mg/kg.The reasonableness of the predicted results was tested,and the result showed that the cultivated land security threshold in the geological high background area was set reasonably.