基于镉污染风险的湖南省龙山县百合种植区安全区划

湖南省龙山县作为我国重要的百合生产基地县之一，其土壤却存在一定程度的镉（Cd）污染风险。同时，百合作为一种食药同源的植物，其食用和药用的质量安全标准不一致。因此，在龙山县提出百合种植区安全区划具有重要意义。笔者等在龙山县耕地采集326件表层土壤样品和70件百合样品（配套根系土样），在分析土壤及百合中Cd的含量和土壤中氧化物、有机质、pH等指标的基础上，探讨Cd生物有效性的影响因素，并据此建立百合Cd生物富集系数预测模型，结合土地质量地球化学调查数据预测耕地的百合Cd含量，给出百合种植区安全区划及建议。结果表明，研究区土壤存在Cd污染风险，百合具有质量安全问题。研究区Cd的生物有效性受到土壤CaO、S、P、K2O含量和土壤pH的共同影响。与多元线性回归模型相比，随机森林模型能够更好地预测百合Cd生物富集系数。百合种植区安全区划显示，研究区食用百合优先种植区、药用百合优先种植区、药用百合次级种植区、结构调整种植区面积占比分别为1. 49%、92. 71%、2. 88%、2. 92%，建议大力开发药用百合农产品。该研究成果将Cd污染风险耕地的安全利用与食药同源农产品的质量安全有效衔接，完善了受污染耕地安全利用的工作方法，为推动龙山县百合产业发展提供了科学依据。

Safety Zoning of Lily Planting Regions Based on Cadmium Pollution Risk in Longshan County, Hunan Province

Longshan County of Hunan Province, as one of the important lily production bases in China, has a certain degree of cadmium (Cd) pollution risk in its soil. Meanwhile, lily, as both an edible and medicinal plant, has inconsistent quality and safety standards for food and drug. Therefore, it is of great significance to propose safety zoning of lily planting regions in Longshan County.Methods: 326 samples of surface soil and 70 samples of lily (corresponding to rhizosphere soil samples), which were collected from cultivated land in Longshan County, were analyzed in terms of the Cd contents of soil and lily, as well as oxides, organic matter, pH and other indicators of soil. On this basis, the influencing factors of Cd bioavailability were explored. Accordingly, the prediction model of Cd bioconcentration factors of lily was established to predict the Cd content of lily in cultivated land, and the safety zoning and suggestions for lily planting regions were put forward by combining with the data from geochemical survey of land quality.Results:The results show that the soil is at the risk of Cd pollution and there are some quality and safety problems with lily in study area. The bioavailability of Cd is jointly affected by the CaO, S, P, K2O contents and pH value of soil in study area. Compared with the multiple linear regression model, the random forest model can better predict the Cd bioconcentration factors of lily. The safety zoning of lily planting regions show that the edible lily priority planting regions, the medicinal lily priority planting regions, the medicinal lily secondary planting regions, and the structural adjustment planting regions account for 1.49%, 92.71%, 2.88% and 2.92% in study area, respectively, and it is suggested to energetically develop agricultural products of medicinal lily.Conclusions: The study results effectively connect the safe utilization of Cd- contaminated cultivated land with the quality and safety of the edible and medicinal agricultural products, enhance the method of the safe utilization of contaminated cultivated land and provide scientific supports for promoting the lily industry development of Longshan County.