不同土地利用方式下川芎镉的累积特征及健康风险评估

为研究土地利用方式对川芎镉累积及与人体健康的关系,以彭州川芎种植区的菜-药、稻-药(翻耕)、稻-药(免耕)和旱地种植方式下土壤和川芎为研究对象,采用统计分析法和靶标危害系数法(THQ)研究了川芎地上部分和地下根茎镉累积的特征及其对人体的健康风险贡献,结果表明:四种土地利用方式下,川芎种植土壤中Cd含量平均为0.73mg/kg,超过国家二类土壤标准(GB 15618—1995);川芎植株中镉的含量由高到低依次为菜-药免耕翻耕旱地方式,均超过《川芎地理标志保护产品》标准。菜-药种植中土壤镉含量显著高于其他三种方式,在该方式下,川芎植株中地上部分镉含量是根茎的1.67倍,超过《地理标志保护产品》标准9.46倍,超过《食品污染限量标准》1.62倍,根茎中镉含量超过《绿色行标》0.11倍。本研究中,川芎地上部分与种植土壤在镉含量上呈显著线性相关,而川芎根茎与土壤在镉含量上相关性不明显;川芎地上部分对人体镉的健康风险贡献(THQ)值平均为63.18%,是根茎(11.50%)的5.49倍。

Accumulation of Cadmium by Ligusticum chuanxiong and Its Associated Health Risk under Different Land Use Types

In order to analyze the influence of land use types on cadmium accumulation of L. Chuanxiong and its contribution to health risk, four different land use types as vegetable-herb, paddy-herb (tillage), paddy-herb (no-tillage) and dry land were investigated in the Pengzhou herb-plantation area by using statistical analysis and THQ method. Results showed that the average content of the four types of soils was 0.73 mg/kg, exceeding the standard of GB 15618-1995. The total Cd concentration in L.Chuanxiong plant showed a decreasing order from high to low in the four types as vegetable soil > no-tillage soil > tillage soil > dry land and exceeded the standard of product of geographical indication Dujiangyan Chuanxiong, too. Furthermore, the content of Cd in the vegetable-herb type was significantly higher than that in the other three types. Under this type, the cadmium concentrations in the over ground part of L.chuanxiong were 9.46 times those of the "product of geographical indication" and exceeded the maximum levels of contaminants in foods by 1.62 times, too. The content of Cd in the acrial part was 1.67 times higher than that in rhizome, while the latter exceeded the foreign trade industry standards by 0.11 times. Based on the study, cadmium concentrations in the over ground part of L. Chuanxiong had significantly linear correlations with those in soil, while it was not the case for rhizome. The over ground part accounted for a mean factor of 63.18% to human health risk and was 5.49 times that of the rhizome (11.50%).