水稻是本省主要的糧食作物，品質的提高，產量的增加為當務之急，因此在有效 的害
蟲管制方法發展成功以前，農藥的使用仍為無可避免的。本省自1952年至1978年 農藥
的消耗額由每年二百萬元台幣增加至廿五億元台幣，如此大量的農藥投人農 田 中而其
對環境的影響卻知之有限，這些問題亟須加以研究則農林保護及環境的安全均有 相當
意義。
1971年Metcalf 首先創立模擬生態系統作為評估農藥安全度的方法。茲經修正其 中生
物相及理化因子以適合本省水稻田條件並利用放射性標誌之殺蟲劑施入模擬生態 系統
中，經過一段時間再分析食物鏈中，農藥代謝產物的分佈。食物鏈中包括︰水稻
(Oryza sativa indica)， 小稻蝗(Oxya intricata)，褐飛蝨(Nilaparvata
oryzae)， 狼蛛(Lycosa pseudoannulata)， 藻(Oedogonium crdiacum)， 浮 萍
(Spirodela polyrrhiza)，田螺(Cipangopaludina chinensis)， 水蚤(Daphnia
pulex)，蚊幼蟲(Culex p. fatingans)，大肚魚(Gambusia affinis)，藉這些生 物作
八種代表性藥劑滴滴涕，靈丹，阿特靈、地特靈，加保利，治滅蝨，巴拉松，馬 拉松
，在此模擬生態系統中進行檢定。其結果發現，有機氯殺蟲劑非常安定，具高度 的生
物蓄積作用及低度的生物分解指數。有機磷及氨基甲酸酯類殺蟲劑的生態加成值 較低
，但生物分解指數即顯偏高，比較模擬生態系統中及田間的資炓可知利用此水 田生態
模擬系統配合同位素技術以研究本省農藥在田間的代謝情形及評估農藥的安全性 是可
行而且可靠的。
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Rice is the major crop plant in Taiwan, the maintaining of is quality and
quantity is very important. For this reason, it is necessary to use
chemical agents to control the rice pest before the other effective pest
management method is established. For many years a huge quantities of
pesticides have been introduced to the rice paddy field by farmers. but
we are in ignorance of fate of the pesticides in the rice paddy field.
The value of pesticides used has risen from NT$ 2 million in 2952 to NT$
2.5 billion in 1978. This enormous increase of pesticide consumption in
Taiwan needs to investigated to determine its effect on the quality of the
environment.
The model ecosystem developed by Metcalf et al.(1971) was modified by
changing organisms associated with the food chains to fit rice paddy
conditions, and the fate of radiolabeled insecticides in the modified
model ecosystem was examined. The radiolabled products were transfered
through the food chains, e.g., rice (Oryza sativa indica), grasshopper
(Oxya intricata), brown planthopper (Nilaparvata oryzae), wolf spider
(Lycosa pseudoannulata), alga (Oedogonium cardiacum), duckweed (Spirodela
polyrrhiza), snail (Cipangopaludina chinensis), water flea (Daphnia
pulex), mosquito fish (Gambusia affinis). The distribution and fate of
eight 14C radiolabeled insecticides DDT, 4-HCH, aldrin, dieldrin;
carbary1, MTMC; malathion, parathion were evaluated in a laboratory rice
paddy model ecosystem. Organochlorine insecticides were relatively stable
under the rice paddy model ecosystem conditions and was bioconcentrated
and stored over a 30-day period in the tissue of the organisms. The high
values for the organochlorine pesticides are in significant contrast to
the low ecological magnification values and high biodegradability indices
found with organophosphorus and carbatmate insecticides. The rice paddy
model ecosystem, with the use of radiolabeled insecticides, is the most
convenient tool for studying the fate and environmental effects of
pesticides to be used in rice paddies and this technology can be used in
every laboratory.