Abstract:
Exposure to pesticide imposes serious long term risk to human
beings. The exposure level ("0.018 mg/kg/day) of pesticides in
Bangladesh is much higher than that of expected level ( 0.005
mg/kg/day). So, there is a significant risk of exposure hazards
of pesticides to human and other nontarget species in Bangladesh.
Runoff, spillage, washing of pesticides' containers in pond water
contribute pesticides residues to ground water and surface water
in Bangladesh. 44.8 microgram /liter concentration of DDT
entered into pond from adjucent rice field through drains and
soil. Concentration of 19.5 ppb, 35ppb, 10ppb of DDT in water
samples of Bangladesh Institute "of Technology, Khulna;
Kitonkhola, Barishal and Amin Bazar, Mirpur respectively and 0.23
ppb, 0.198 ppb of heptachlor in water samples of Amin Bazar,
Mirpur and Kitonkhola, Barishal of Bangladesh exceed acceptable
limits of pub in case of DDT and 0.03 ppb in case of heptachlor.
So, there is a significant risk of water pollution.
Ground water and surface water vulnerability in the case of DDT
and Atrazine were carried out. Application of 1-1.12 kg/ha rate
for Atrizine in low land rice field of coastal area impose
moderate risk on ground water. Pesticide contamination of surface
water by runoff and spillage, adulteration of pesticides in pond
drainage from irrigation project cause toxicity to fish species
and aquatic organisms. Considerable amount of organochlorine
insecticides were found in water samples of depressions near rice
fields which indicate lacks of control mechanisms.
Considering storage loss, Tuyen's equation has been modified to
estimate pesticide residue in human body. However this requires
further experimental varification. Presence of significent amount
of pesticide residue in food, dry fish etc are matter of concern. The residue of pesticide in human body due to consumption of rice
and wheat was estimated to be 1.76 x 10-5 mg/day/person in
Bangladesh. Although the level of pesticide residue in daily
consumption of food is still low as compared to other developing
countries, yet it is a matter of concern due to lack of medicre
facilities and poverty in Bangladesh. Isotherms of carbicorn,
malathion, diazinon in alluvial soil were established. Atraction
of carbicorn, malathion to this soil is greater than that of
diazinon. Thus use of diazinon impose greater risk than use of
carbicorn and malathion.
