| Abstract | This study was performed in order to establish the present contamination in the eggs
of the waterfowl, the Little Grebe (Podiceps ruficollis) and the Yellow Bittern (Ixobrychus
sinensis), situated in the Songkhla Lake Basin (SLB) in Southern Thailand in 1993.
These species were selected as representative resident birds, integrating the residual
levels in the studied area. The birds are distributed all over the Southeast Asia and can,
therefore, serve for comparative studies as time trend monitoring and regional distribution
of contaminant in more contaminated areas.
Twenty-five eggs from seven nests of the Little Grebe and three nests from the
Yellow Bittern were analyzed individually for persistent organochlorine residues which
included aldrin, dieldrin, cis- and trans-chlordane, heptachlor, lindane, 2,4'-DDE, 2,4'-DDT,
4,4'-DDE, 4,4'-DDD, 4,4'-DDT, and seven chlorinated biphenyls. The results showed that
4,4'-DDE had the highest concentration in both birds with a range of 170.12-4918.00 µ.g/ kg
fat (16.17-470.21 µ.g/kg fresh weight) in the Little Grebe, and 952.01-2071.16 µ.g/kg fat
(40.60-111.02 µ.g/kg fresh weight) in the Yellow Bittern. However, the results were in
general at low levels compared to other species in other reports.
A literature reviews of organochlorine compounds in bird-eggs was conducted but did
not reveal any publications on the investigated species or related birds.
The results showed that the SLB is well suited as a baseline, which can serve as a
background to more contaminated areas, and for future time trend studies. |