and Integrated Pest Management - part - usaid

PF;TICl)I:B RI'NIID I S iN I'IIJAIL NI) 3-I 5
The analyses showed that trace anoutlLs of organochlorinc per;istCd in50%
of I(4 waler samples and 90% of 602 sedimcnt samples collected from 30 main
canals, rivers and water reservoirs for drinking. Besides several kinds of
organochlorines, traces of organophosphates such as dimelhoate, diazinon,
malathion, mcthyl paratiion, fenitrothion, and profcnophos were also found in
water, sediimcnt and soil, especially in the soil taken from cropped fields and
orchard ;.
Organochlorine insecticides - mainly DDT, endrin, aldrin, and dieldrin ­
which wcre most frequently found in environmental s:'mples, have been used for
more than two (ecades illplar ,protection, and DDT also in malairial eradication
in Tha ilamu. I li rccently, with the evidcnce that DDT has become widely
distihute! in Ihe find chain and th e 'iiNumm., an(f that it is a dangerous
substance, its ii;e in agriculture has hCcorome limited. DDT is now permitted
only for the conrol 1ofniialaria. The insecticide, endrin, was subscquenly banned
from use in Thailand in 1981 for the same reasons. The persistent
organochlorine pesticides appear to have been widely distributed in all
au-riculitiral areas through ditches and ca,,nals, to accumulate in sedimeat and soil
and end up in living organisms such as fi.sh and wildlife. For example, 90% of
samples of fish and shell fish, both marine and resh water, collected from market
places and waler sources in central Thailand contained residues of DDT, aldrin,
and dicldrin. H-towever, the levels detected were not alanning.
An investigation on pesticide residie levels in birds was conducted in 1980
by Tayaputch and MahiItikurin (1980). Ninety birds collected froni the central
plain area were classified into 30 species and divided into
their
5 grotips
feeding
according
habits.
to
Results of analyses for pesticide residues in stomach
contents, livers and tissue:: are shown in Table 2. Traces o, 14 organochlorine
pesticides were identified, with the most commonly found
dieldrin.
being DDT
The
and
concentration of residues varied from tissue Ittissue and the
results indicated that DDT and dieldri n detected in the samples were related to
feeding habits of birds. The pesticide levels found were mostly lower than 1
ppm, which has I'een reported in :everal studies to be harmless
laboratory
to treated
experiments
birds in
(Bernard 1966). However, the combined effects of
multiple residues on birds and their long-term consequences should be carefully
examined.
Table 2. Pesticide residues in ppm (ug/g) in stomach contents, livers and
tissues of five groups of birds (fresh wet weight).
Group Residues of total DDT Residues of dicldrin
Carnivorcous
1lerbivorous
Onlivornous
Insectivorous
Birds of prey
stomach
0.09
0. 10
0.20
0. I9
0.25
hver
0.17
0.17
0.11
0.31
0.31
lissue
0. 10
0.05
0.04
0.12
0.13
stomach
0.08
0.07
0.14
0.09
1.05
liver
0.09
0.12
0.08
0.12
0.03
tissue
0.03
0.03
0.03
0.06
0.16