Yang Yang, Chen Wei-Ping, Li Yan-Ling, Wang Mei-E, Peng Chi
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2016 Dec 8;37(12):4800-4805. doi: 10.13227/j.hjkx.201606073.
Cadmium (Cd) can cause adverse health effects and is a subject of concern in rice consumption. The uncertainty analysis helps improve the accuracy in the risk assessment for Cd in soil-rice system. A regional investigation on Youxian prefecture, southern China, was conducted to analyze the Cd concentration in rice. Based on the species sensitivity distribution model (SSD), health risk assessment model, and Monte Carlo simulation, the accumulation characteristic of Cd in soil-rice system, accumulation risk of Cd in soil, and health risk of Cd concentration in rice were determined. The results showed that the plant uptake factor (PUF) of Cd of rice was well fitted by the SSD model. The mean level of PUF was 1.86, with a significant spatial heterogeneity. The rice produced in WL county tended to accumulate a high level of Cd. There was no significant relationship between concentrations of Cd in soil and rice, suggesting that of rice renders the Cd risk management very difficult. The pollution load index of Cd in soil was 2.4, which belonged to a moderate contamination level. Under current accumulation condition of Cd in soil, there would be a 90.4% probability for soil Cd concentration to be higher than the national soil quality standard after 10 years. Health risk assessment showed that the average daily dose (ADD) was 2.9 μg·(kg·d), 3.5 fold higher than the WHO limit. About 93.9% of the adult populations consuming rice cropping in affected areas had the risk that the daily Cd intake was above the WHO limit. The health risk index (HRI) was around 2.1 to 4.7. The probability for health risk index (HRI) higher than 5 was 21.5%, suggesting a high health risk. When the soil pH was lower than 5.5, the probability for HRI higher than 1 was 95.3%, and when the soil pH was higher than 6, the probability for HRI higher than 1 reduced to 68.1%. An improved management of soil pH values would be needed for a better and safer rice production. The combination of uncertainty analysis, species sensitivity model and health risk assessment model was validated to be feasible and reliable in the risk analysis.
镉（Cd）会对健康产生不利影响，是大米消费中备受关注的问题。不确定性分析有助于提高土壤-水稻系统中镉风险评估的准确性。对中国南方攸县进行了区域调查，以分析大米中的镉浓度。基于物种敏感性分布模型（SSD）、健康风险评估模型和蒙特卡罗模拟，确定了土壤-水稻系统中镉的积累特征、土壤中镉的积累风险以及大米中镉浓度的健康风险。结果表明，SSD模型能很好地拟合水稻对镉的植物吸收因子（PUF）。PUF的平均水平为1.86，具有显著的空间异质性。WL县生产的大米往往积累高水平的镉。土壤和大米中的镉浓度之间没有显著关系，这表明大米使得镉风险管理非常困难。土壤中镉的污染负荷指数为2.4，属于中度污染水平。在目前土壤镉的积累条件下，10年后土壤镉浓度高于国家土壤质量标准的概率为90.4%。健康风险评估表明，平均每日摄入量（ADD）为2.9μg·(kg·d)，比世界卫生组织的限值高3.5倍。在受影响地区食用水稻种植大米的成年人口中，约93.9%有每日镉摄入量超过世界卫生组织限值的风险。健康风险指数（HRI）约为2.1至4.7。健康风险指数（HRI）高于5的概率为21.5%，表明健康风险较高。当土壤pH值低于5.5时，HRI高于1的概率为95.3%，当土壤pH值高于6时，HRI高于1的概率降至68.1%。为了实现更好、更安全的水稻生产，需要改进土壤pH值的管理。不确定性分析、物种敏感性模型和健康风险评估模型相结合在风险分析中被验证是可行和可靠的。
