| 基于农产品安全的土壤重金属有效态含量限值推定方法 |
| 摘要点击 2300 全文点击 683 投稿时间：2019-01-23 修订日期：2019-04-02 |
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| 中文关键词 农产品安全 有效态含量限值 物种敏感性分布 镉 铅 |
| 英文关键词 agricultural product quality threshold of available concentration species sensitivity distribution Cd Pb |
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| 中文摘要 |
| 相较于土壤重金属总量标准，有效态含量限值与农产品质量相关性更强，可更科学地指导土壤污染防治工作.通过典型重金属污染区域案例研究，在统计分析区域农田土壤重金属总量、有效态含量和不同水稻品种重金属蓄积量的基础上，运用物种敏感性分布（SSD）法，推定土壤中镉和铅的有效态含量限值.结果表明，大冶市农田土壤中Cd和Cu样本超标率分别是90.7%和42.6%，表明大冶市农田土壤存在较为广泛的Cd和Cu污染；糙米Cd和Pb的含量分别有50.9%和89.8%的样本超标，其平均值分别是相应农产品污染物限量标准的2.95倍和6.75倍，表明大冶市稻米受Cd和Pb污染严重.利用BurrⅢ型分布拟合样品中8个水稻品种富集Cd和Pb的SSD曲线，依据农产品中污染物限量标准推导计算得出，保证95%水稻品种糙米不超标的土壤重金属Cd和Pb有效态含量限值分别为0.02 mg·kg-1和0.005 mg·kg-1.比较于该区域土壤中Cd有效态含量调查数据和其他国家或研究有效态含量限值，Cd有效态含量推导限值较为科学，可应用于当地土壤污染防治实践.在大冶地区土壤Pb可能不是稻米Pb的主要来源，水稻这一物种对于Pb有效态含量限值的推导不具有代表性，同时缺乏稻米在低积累水平和不同土壤污染水平下对Pb的累积数据，因而Pb有效态含量限值不具实际指导意义. |
| 英文摘要 |
| Based on the total and available concentrations of heavy metal elements in agricultural soil, and the concentrations of heavy metals in rice collected from Daye city, Hubei province, and the thresholds of available concentrations of heavy metals were derived by species sensitivity distribution (SSD). The over-standard rates of Cd and Cu in the soil were 90.7% and 42.6%, respectively, which indicates that agricultural soil in Daye city exhibits signs of Cd and Cu pollution. The rates of Cd and Pb were 50.9% and 89.8% in brown rice samples, respectively, which exceeds the safety standards of agricultural products. The SSD curves for Cd and Pb were fitted with BurrⅢ distribution based on the ratio of the concentration in brown rice and the available concentration in the soil. The hazardous concentrations (HC5) were derived inversely from the agriculture product safety standards. The thresholds of available Cd and Pb were 0.02 mg·kg-1 and 0.005 mg·kg-1, respectively. Compared with those of available Cd in other countries and studies, the threshold of available Cd is scientifically shown to be reasonable. Soil is not necessarily the main source of Pb in rice; thus, the rice species does not represent the derivation of the threshold of available Pb. Moreover, a lack of the accumulation data of Pb at low accumulation levels and multiple soil pollution levels leads to unreliable derivation. The results indicate that the threshold of available Pb does not have practical significance in soil pollution control. |
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