石灰氮对早竹林土壤重金属污染潜在生态风险及竹笋健康风险的影响

为了解覆盖栽培与施用石灰氮对早竹林土壤重金属污染的潜在生态风险以及对早竹笋重金属健康风险的影响,选择浙江省德清县3个主要早竹笋产区作为试验点,采用电感耦合等离子体质谱(ICP-MS)法检测了3种不同处理(不覆盖、覆盖和覆盖后施用石灰氮)下早竹林土壤和笋中的Cr、As、Hg、Ni、Cd和Pb等6种重金属的含量。结果表明,各试验点土壤中重金属含量排序均为Cr>Pb>Ni>As>Cd>Hg,覆盖栽培使土壤酸化,重金属富集,而覆盖栽培后施用石灰氮则可改善重金属的富集水平;覆盖栽培后笋中Cr、As、Hg、Ni、Cd、Pb 6种重金属含量最大值分别为0.23、0.06、0.006、0.65、0.04、0.10 mg·kg^-1, 均未超出标准森林食品质量安全通则(LY/T 1777-2008)和食品安全国家标准食品中污染物限量(GB 2762-2012)中的限值。覆盖栽培后施用石灰氮能够降低笋中重金属的积累,同时明显降低土壤重金属综合潜在生态危害指数,通过食用笋摄入6种重金属的健康危害指数(HI)均低于美国环保署(US EPA)推荐的最大可接受水平1.0,无明显健康风险。研究表明,施用石灰氮有助于缓解覆盖栽培所引起的重金属污染现象。本研究为石灰氮在林业生产上的应用提供了科学依据。

Effects of Lime Nitrogen on Potential Ecological Risk of Heavy Metal Pollution in Phyllostachys violascens Stands Soil and Health Risk of Bamboo Shoot

In order to explore the potential ecological risk of heavy metal pollution in soil and the health risk of heavy metals in edible Phyllostachys violascens shoots under mulching cultivation and the application of lime nitrogen, three main Phyllostachys violascens shoot producing areas in Deqing County, Zhejiang Province were selected to be sampling sites. The contents of Cr, As, Hg, Ni, Cd and Pb in Phyllostachys violascens soil and Phyllostachys violascens shoots under three different management modes (no mulching, mulching and applying lime nitrogen after mulching cultivation) were determined by ICP-MS method. The results demonstrated that heavy metal content in the soil of three different management modes followed the order of was Cr > Pb > Ni > As > Cd > Hg, mulching led to the soil acidification and heavy metal enrichment, but the application of lime nitrogen could diminish the enrichment level of the soil. After mulching cultivation, the maximum contents of six heavy metals in bamboo shoots were 0.23, 0.06, 0.01, 0.65, 0.04 and 0.10 mg·kg^-1, respectively. Within the limits of the Standard Forest Food Quality and Safety guidelines (LY/T 1777-2008) and the Food Safety National Standard Food contaminant limits (GB 2762-2012). Lime nitrogen can reduce the accumulation of heavy metals in bamboo shoots under mulching cultivation. The comprehensive potential ecological hazard index of heavy metals in soil under mulching cultivation decreased significantly after the application of lime nitrogen. The health hazard index (HI) of 6 heavy metals ingested by bamboo shoots was lower than the maximum acceptable level recommended by US EPA (1.0), and there was no significant health risk. The results showed that the application of lime nitrogen could alleviate the pollution of heavy metals caused by mulching cultivation.This study provides a scientific basis for the application of lime nitrogen in forestry production.