A systematic review on food lead concentration and dietary lead exposure in China

Background By synthesizing results from primary studies, systematic review can provide empirical information of concerned problems. This study aimed to review the available surveillance data from studies reporting the contamination surveillance of food lead in China. Methods Relevant studies were identified by systematically searching Chinese Biological Medicine Database and China National Knowledge Infrastructure using the key term of "lead" for surveillance data published in Chinese between 2006 and 2012. To avoid potential selection bias, all articles were evaluated by two independent reviewers, and the disagreements were resolved by discussion or the third author was asked to arbitrate. Results Among 269 identified publications on surveillance data of lead in food, 43 articles met the defined inclusion criteria. The food samples were divided into 11 groups (cereal grains and pulses, fish, eggs, vegetables, meat, edible fungi, milk and dairy products, fruits, offal, tea and preserved egg). Surveillance data of publications were reviewed to calculate the weighted mean and rate exceeding maximum levels. Our results indicated that the highest lead concentration was 1.937 mg/kg in tea. The total percentage of samples exceeding the maximum levels was 5.57%. Dietary exposure to lead was assessed by combining the weighted mean concentration of surveillance data with national consumption data in 2002. In this review, dietary intake of lead was 1.232 mu g/kg b.w./day. Conclusion Further control measures should be taken to reduce exposure to lead, from both dietary and non-dietary sources.