Concentration and potential health risk of heavy metals in market vegetables in Chongqing, China.

Concentration and daily intake (DI) of heavy metals (Pb, Zn, Mn, Cu, Cd and Cr) in market vegetables in Chongqing of China are investigated and their potential health risk for local consumers is simultaneously evaluated by calculating the target hazard quotient (THQ). The results showed that the measured Pb and Cd concentrations exceeded the safety limits given by FAO/WHO and Chinese regulations, indicating serious contamination of market vegetables by these metals. As respective DI values for Pb, Mn and Cd were also above the international guideline bases, health risk to the consumers is obvious. The individual THQ for Pb and Cd in pakchoi and Cd in mustard, and the combined THQ for all metals in each vegetable species excluding cos lettuce were above the threshold 1.0, implying the obviously adverse effect on health. Therefore, attention should be paid particularly to the potential hazardous exposure to vegetable heavy metals, especially for Pb and Cd, over a lifetime for people in Chongqing.

Heavy metals of vegetables and soils of vegetable bases in Chongqing, Southwest China.

There is a growing concern over environmental and ecological safety in China owing to rapid urbanization and industrialization and increasing reliance on agrochemicals in the last several decades. Excessive accumulation for some essential trace elements (e.g., zinc, copper) or low concentration of toxic elements (e.g., cadmium, lead) in agricultural soils may not only result in environmental contamination but also affect food quality and safety. This study is conducted to investigate eight heavy metal elements (Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb) of soils and vegetables in twenty vegetable bases in Chongqing, one of the municipalities directly under the jurisdiction of central government. The results shows that soils investigated in this study are heavily contaminated with cadmium and lead, which exceed the national (China) and local (Chongqing) background values. All the study vegetables are below the national sanitary standards for vegetables in China with one exception of lead concentration of vegetables in the district of Dadakou. All the 20 bases in this study can be divided into three groups: group 1 including Rongchang, Wanzhou, Bishan, Yubei, Jiangjin, Wansheng and Fuling, group 2 containing Dadukou, Changshou, Jiulongpo, Ba'nan, Yongchuan and Jiangbei and group 3 comprising Nan'an, Beibei, Shapingba, Dazu, Tongnan, Tongliang and Hechuan. The soil contamination is group III > group I > group II while the order of the plant contamination is reverse.