Musks and organochlorine pesticides in breast milk from Shanghai, China: levels, temporal trends and exposure assessment.

The concentrations of musks (polycyclic musks and nitro musks) and traditional organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and its metabolites (DDT, DDE, DDD, and total DDTs), hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs) in breast milk collected in Shanghai, China during the period 2006-2010, were determined. The total concentrations ranged from 4.7 to 276.2 (median: 58.4) ng/glipid weight (lw) for musks and from 88.3 to 2532.9 (median: 1003.8) ng/glw for OCPs. 4,4'-DDE (median: 655.4 ng/glw) was the predominant OCP, followed by β-HCH (median: 172.5 ng/g lw), and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran) (median: 17.7 ng/g lw) was the dominant musk. There was no statistical correlation between total musk concentrations, and HCB, HCHs, DDTs or total OCP concentrations, indicating their different exposure routes and metabolism in humans (p=0.182-0.325). Clear reductions in temporal trends in the levels of DDTs and HCB, especially HCHs (p<0.01) were observed during the sampling period, and the high DDE/DDT ratios in the samples indicated past exposure to DDTs. The relatively high median concentrations of HHCB and HHCB-lactone in 2010 suggested a probably increasing tendency. There were statistically significant influences regarding maternal age and parity on OCP accumulation (p=0.001-0.002), but no significant effect on musks was found (p=0.542-0.919). Musk exposure in neonates via breast milk was 2-3 orders of magnitude lower than suggested provisional tolerable daily intakes (PTDI). The estimated daily intakes for HCB and DDTs were below the PTDI in Canada, however, 56% of those for HCHs exceeded the Canadian PTDI. OCP contamination of breast milk requires further attention.