SERUM DDT AND DDE LEVELS IN SINGAPORE GENERAL-POPULATION

A simple and fast method was used to determine ,1'-(2,2,2-trichloroeth ylene)-bis(4-chlorobenzene) (DDT) and 1,1'-(2,2-dichloroethylidene)-bi s(4-chlorobenzene) (DDE) in blood serum. Serum samples pre-treated wit h formic acid were extracted with n-hexane and determined by gas chrom atography (GC-ECD), using PTE-5 capillary column. Detection limits for DDT and DDE were 0.5 ppb. Recovery with a fortified pooled sample at 1 ppb level was 107.0% for DDT and 106.0% for DDE. At 10 ppb level, th e recoveries for DDT and DDE were 96.1% and 92.7%, respectively. Eight y-nine random blood samples collected from volunteers were analyzed. T he geometric mean (GM) serum level of DDT was 1.9 ppb (0.2-8.9 ppb) an d that of DDE was 10.8 ppb (1.5-88.1 ppb). There was a positive correl ation between DDE and DDT level (r = 0.33, P < 0.01). The serum DDE le vel was positively correlated with age (r = 0.49, P < 0.01) and DDT x Age (r = 0.62, P < 0.01). No correlation was observed between DDT and age. These results suggest that DDE, a metabolite of DDT, is cumulativ e in the body. Therefore blood DDE could be used as a cumulative expos ure marker for DDT, whereas blood DDT may be used to reflect its recen t exposure. (C) 1997 Elsevier Science B.V.