Concentrations of organochlorine pesticides (OCPs) in human blood plasma from Hong Kong: markers of exposure and sources from fish.

Previous studies revealed that food, particularly fish products, is the major source for human exposure to organochlorine pesticides (OCPs). Our previous studies revealed that contamination of Hong Kong market fish with DDT was 0.74-131 with a mean of 12.2 ng g(-1), ww, a result suggested that local people might be exposed to hazardous concentrations of OCPs. Therefore, the present systematic study was conducted to determine concentrations of OCPs in blood plasma of Hong Kong residents, develop marker substances and evaluate sources of 19 individual OCPs from fish. Concentrations of ∑OCPs, ∑DDTs and ∑HCHs ranged from 294 to 9732, 172 to 8842, and 115 to 1616 ng g(-1) lipid weight (lw), respectively. These concentrations were greater than those in blood of people from most developed countries but lower than those from most developing countries. The upper age group (>50 years) had significant (p<0.05) greater concentrations of OCPs than other groups. Furthermore, concentrations of OCPs in males were significantly (p<0.05) greater than those in females. p, p'-DDE was the predominant congener and marker substance of DDTs, while β-HCH was the predominant congener and marker substance of HCHs. p, p'-DDE was more correlated with ∑OCPs (r(2)=0.830, p<0.05) than other individual OCPs, which suggested that p, p'-DDE is a good marker for accumulation of OCPs in blood plasma. Concentrations of individual OCPs were significantly correlated with not only their corresponding total concentrations in fishes from Hong Kong markets (r(2)=0.391, p=0.024), but also their bioaccessible fractions, which were estimated by an in vitro digestion method (r(2)=0.784, p=0.000). These results suggested that the in vitro gastrointestinal model is a more accurate method to evaluate accumulation of and health risks caused by dietary intake of OCPs. This study, which was the first systematic study to investigate concentrations of OCPs in blood of Hong Kong people, provides a baseline to which future measurements can be compared.