Historical trends in human dietary intakes of endosulfan and toxaphene in China, Korea and Japan

Recently, the Stockholm Convention prohibited the use of toxaphene and has been reviewing endosulfan. The historical use of these pesticides may contaminate food and tend to accumulate in the food chain. In this study, to evaluate the spatial and temporal trends of food contamination, the endosulfan and toxaphene levels were measured in pooled 24-h food composite samples from Chinese (n = 10), Korean (n = 10) and Japanese (n = 40) adults in the 1990s and 2007–2009. Endosulfan was detected in 32 of 40 samples from Japan, but its levels (sum of α- and β-isomers) were low in both the 1990s and 2009 (range as geometric mean (geometric standard deviation) [GM (GSD)]: 0.96 (1.6)–1.42 (1.4) ng kg−1 d−1). The dietary intakes of endosulfan in Seoul as GM (GSD) were 38.68 (1.3) ng kg bw−1 d−1 in 1994 and 92.17 (4.4) ng kg bw−1 d−1 in 2007, and significantly higher than those in Japan (p < 0.05). The samples from Beijing showed a 50-fold increase in the endosulfan levels from 1993 (GM: 0.58 ng kg−1 d−1) to 2009 (GM: 24.91 ng kg bw−1 d−1) (p < 0.05). Toxaphene was detected in 33 of 40 samples from Japan. The dietary intake of toxaphene in Japan (sum of Parlars #26, #50 and #62) was 0.32–1.21 ng kg bw−1 d−1 (range as geometric mean) and no temporal trend was observed. The dietary intake of toxaphene in Seoul increased significantly from 0.2 ng kg bw−1 d−1 (GM) in 1994 to 3.6 ng kg bw−1 d−1 (GM) in 2007 (p < 0.05). Only one of 10 pooled samples from Beijing contained a detectable level of toxaphene (0.3 ng kg bw−1 d−1). For the entire population, the risk of adverse health effects from dietary intakes of endosulfan and toxaphene is unlikely. However, the concentrations of endosulfan in several samples exceeded 10% of the acceptable daily intake limit value of 6 μg kg bw−1 d−1 set by the World Health Organization (WHO). It appears important to refine dietary intake estimates targeting food types and source identification to ensure safe food for consumers.

► An exponentially increasing trend in endosulfan exposure was observed in Beijing.
► The significant increase over time for toxaphene in Seoul was remarkable.
► The concentrations of endosulfan in several samples in Korea exceeded 10% of ADI.