菜用睡莲栽培土壤和灌溉水铅、汞及镉安全指标验证试验

Verification Experiment on the Safety Index Limits for Pb,Hg and Cd Content of Soil and Irrigation Water for Edible Waterlily Cultivation

菜用睡莲(Nymphaea tetragona Georgi)是湖北省开发的一种以叶柄及花柄为产品的新型水生蔬菜。为了评价菜用睡莲对铅、汞及镉3种重金属的吸收富集能力,并比较有关标准中关于土壤和灌溉水中铅、汞及镉安全指标限量值的适用性,利用睡莲盆栽进行了3个独立的模拟试验。结果表明,处理土壤铅、汞及镉含量与灌溉水及菜用睡莲产品中的铅、汞及镉含量分别呈显著或极显著正相关。菜用睡莲对土壤重金属的富集系数(PUF)为镉0.99~3.26>汞0.50~1.50>铅0.00~0.02,对这3种重金属均有良好的富集效果,可以用于土壤和水体中重金属的吸收清除。在处理土壤铅含量为65 mg/kg时,菜用睡莲产品的铅含量为0.3 mg/kg,达到GB 2762-2012叶菜蔬菜的上限值以及NY/T 5010-2016规定的铅含量上限值,不能保障菜用睡莲产品铅含量符合GB 2762-2012的规定。利用回归方程计算的理论值表明,土壤铅≤65 mg/kg、汞≤0.05 mg/kg及镉≤2.88 mg/kg时,菜用睡莲产品符合GB 2762-2012的限量值规定(铅0.3 mg/kg、汞0.01 mg/kg、镉0.2 mg/kg)。如果实行种养结合模式,则NY/T 5361-2016规定的土壤和水铅、汞及镉含量限量值指标更为适宜。

Edible waterlily （Nymphaea tetragona Georgi） is a newly developed aquatic vegetable crop, with leaf stalks and flower stalks as product organs, in Hubei province. In order to evaluate the absorption and accumulation ability of edible waterlily to heavy metals including Pb, Hg and Cd, and the suitability of safety index limits for Pb, Hg and Cd content of soil and irrigation water, three isolated simulation experiments were carried out with pot-cultivated edible waterlily. The results are as follows, the content of Pb, Hg and Cd of treated soils were significantly or very significantly positively correlated with the content of Pb, Hg and Cd of irrigation water respectively and with those of the product organs of the edible warerlily respectively. The edible waterlily had high absorption and accumulation ability to heavy metals and the plant uptake factors（PUF） were 0.00~0.02 for Pb, 0.50~1.50 for Hg and 0.99~3.26 for Cd. Therefore, the edible waterlily can also be used to eradicate heavy metals from polluted soil and water. When cultivated in the treated soil with 65 mg∕kg Pb, the Pb content of the product organs of edible waterlily reached to 0.3 mg∕kg, the maximum limit determined by GB 2762-2012, thus the soil with the maximum limit of Pb content, determined by the ministerial standard--NY∕T 5010-2016, is not suitable for cultivating edible waterlily with product Pb content below 0.3 mg∕kg. When cultivated in the soil with 65 mg∕kg Pb, 0.05 mg∕kg Hg and 2.88 mg∕kg Cd as maximum limits, which were theoretically calculated by regression equation, the product of the edible waterlily will compliant with the safety maximum limits, i.e., 0.3 mg∕kg Pb, 0.01 mg∕kg Hg and 0.2 mg∕kg Cd, which were determined by GB 2762-2012. The Pb, Hg and Cd maximum limits determined for soil and water by NY∕T 5361-2016 standard are more suitable for quality edible waterlily production in edible waterlily-fish culture system.