Yang Yang, Li Yan-Ling, Chen Wei-Ping, 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. 2017 Jan 8;38(1):399-404. doi: 10.13227/j.hjkx.201606075.
The consumption of vegetables is a probable cause of Cd exposure in several world areas including China.In this study,we selected the prefecture of Youxian,southern China,as a case to analyze the influences of various environmental factors on Cd accumulation in vegetables based on a large scale agricultural and climatologically survey and collection of 585 irrigation water and 625 paired soil-vegetables samples.The results showed the concentration of Cd differed greatly in the irrigation water,soil and vegetables.The average daily dose for the adult populations consumed vegetables cropping in affected areas was slightly above the tolerable daily intake level,suggesting a potential health risk.The vegetables Cd uptake factor followed the natural lognormal distribution,and had a 10 percentile probability of higher than 1.The PUF values exhibited comparable results and appeared to define a reasonable and consistent Cd risk assessment.Many environmental variables (soil pH,soil organic matter,cation-exchange capacity,rainfall,water pH,and nitrogenous fertilizer usage) exhibited significant correlations with the concentrations of Cd in the soil-vegetable system.The canonical corresponding analysis and path model analysis found that soil pH and soil organic matter (SOM) had major direct effects on PUF.The close correlations between rainfall,water pH,nitrogen fertilizer usage and PUF were mainly resuled from the direct effect of soil pH and SOM.The high field-moisture capacity in the study area generated a rapid acidification causing the migration of Cd to weaker bounding sites thus promoting the vegetables uptake.The excessive application of nitrogen fertilizers led to a substantial loss of SOM and worsening of soil acidification ultimately causing increasing Cd accumulation in vegetables.Considering that the soil pH and SOM in the study area were maintained at a low level,the accumulation risk of Cd in soil-vegetable system needs to be addressed.The influence of environmental factors on vegetables accumulating Cd needs to be fully considered for better and safer vegetables production.
在中国等世界多个地区，蔬菜消费可能是镉暴露的一个原因。在本研究中，我们选取中国南方的攸县作为案例，基于大规模农业和气候学调查以及收集的585份灌溉水样本和625对土壤 - 蔬菜样本，分析各种环境因素对蔬菜中镉积累的影响。结果表明，灌溉水、土壤和蔬菜中的镉浓度差异很大。受影响地区种植的蔬菜供成年人群食用的平均每日摄入量略高于可耐受的每日摄入量水平，这表明存在潜在健康风险。蔬菜镉吸收因子呈自然对数正态分布，且有10%的概率高于1。PUF值呈现出类似结果，似乎定义了一个合理且一致的镉风险评估。许多环境变量（土壤pH值、土壤有机质、阳离子交换容量、降雨量、水体pH值和氮肥使用量）与土壤 - 蔬菜系统中的镉浓度呈现出显著相关性。典范对应分析和路径模型分析发现，土壤pH值和土壤有机质（SOM）对PUF有主要直接影响。降雨量、水体pH值、氮肥使用量与PUF之间的密切相关性主要源于土壤pH值和SOM的直接影响。研究区域的高田间持水量导致快速酸化，使镉迁移到结合较弱的位点，从而促进了蔬菜对镉的吸收。过量施用氮肥导致SOM大量流失和土壤酸化加剧，最终导致蔬菜中镉积累增加。鉴于研究区域的土壤pH值和SOM维持在较低水平，土壤 - 蔬菜系统中镉的积累风险需要得到解决。为了实现更好、更安全的蔬菜生产，需要充分考虑环境因素对蔬菜镉积累的影响。
