Regional characteristics of children's blood lead levels in China: A systematic synthesis of national and subnational population data

The blood lead levels (BLLs) of children in China remain notably high in many areas. We aimed to summarise the relevant regional characteristics, identifying problematic areas and the causes of lead pollution. We searched the databases of PubMed, China National Knowledge Infrastructure (CNKI), and Wanfang Data, systematically reviewing 219 articles published from January 2010 to September 2020. In doing so, we assessed the BLLs noted in 220 prefectures across China. Data were organised using Geographic Information Systems (GIS) mapping. Out of a total of 629,627 children sampled, we found that the average blood lead level (BLL) of children included in our study is 50.61 +/- 13.63 mu g/L, which slightly exceeds the 50.00 mu g/L US standard. Within the sample, 8.75% had BLLs higher than 100.00 mu g/L. Children living in Liaoning, Hebei, Shanxi, Jiangxi, Anhui, Fujian, Guizhou, Yunnan, and Guangxi had notably high BLLs, at more than 60.00 mu g/L. A total of 112 municipalities had an average children's BLL above 50.00 mu g/L. Furthermore, Chenzhou, Linfen, Yuncheng, and Hechi had the highest children's BLLs, with average values above 100.00 mu g/L. The leading contributors to lead pollution are lead mining, lead recovery and the smelting industry. Nonetheless, the lead-acid battery industry needs more attention. Although data suggest that BLLs are decreasing in China, many areas still have high BLLs that need to be monitored. Moreover, national standards must improve to decrease acceptable BLL thresholds for children. (C) 2021 Elsevier B.V. All rights reserved.