Hexachlorobenzene in human milk collected from Beijing, China.

High concentration of hexachlorobenzene (HCB) was detected in Beijing breast milk in 2002. In order to identify trend in exposure, 65 breast milk samples were collected from 50 primiparous mothers during 2009-2011. The present concentration of HCB in the breast milk (range: 10.9-160.5 μg kg(-1) fat; median: 55.0 μg kg(-1) fat) was higher than that of the recent national average level and those of other countries or regions. This may be partially due to the previous extensive HCB exposure. A longitudinal study of HCB in human milk within six months postpartum showed that the level did not significantly decreased, and remained stable. The estimated daily intake (EDI) for the newborn (range: 0.045-0.43 μg kg(-1) body weight/d; median: 0.20 μg kg(-1) body weight/d) was also higher than the World Health Organization (WHO) tolerable daily intake value (0.17 μg kg(-1) body weight/d for non-cancer effects). Despite the apparent decrease of HCB body burden in past 10 years, the environmental health hazard from HCB contamination in Beijing remains a concern. Therefore a regular human milk monitoring programs for HCB are needed.