四種農藥對於水生生物的生態風險評估

Ecological Risk Assessment of Four Pesticides in Aquatic System

徐佳妏(Hsu Chia-Wen)

指導教授 ： 謝賢書

共同指導教授 ： 洪慶宜

長榮大學/健康科學學院/職業安全與衛生研究所/碩士(2007年)

https://doi.org/10.6833/CJCU.2007.00147

摘要

摘 要
用於防治農作物病蟲害之化學藥物，其成分與用量可能對生態造成危害。近年來，世界各地則廣泛應用生態風險評估來評估污染物對生態的衝擊。本研究評估貝分替(carbendazim)、免賴得(benomyl)、加保利(carbaryl)、大滅松(dimethoate)等4種農藥的生態風險。依循美國ECOFRAM評估程序，以農田土壤農藥實測濃度經污染物傳輸情境作為環境預期濃度（EEC）；以ECOOX毒性資料庫作為生物效應風險基準值(ERC)，生態風險則以物種效應商數作初步評估，效應超過基準者，以群聚生態風險來進行第二階段推估。
結果顯示，以大滅松對於生態中的水生物種風險值較具顯著，物種效應商數對吳郭魚高達23.1、石蠅高達2.79；群聚生態風險顯示約有42%的水生生物會受影響，超過美國環保署及田納西州管制局所訂之基準值。在管理上應降低大滅松暴露於水生生物所造成的潛在風險。其餘三種農藥則未造成顯著之生態風險。
本研究另以生態系統動力學模式探討農藥之毒性值進入食物鏈關係所產生之影響，以簡單的食物鏈關係，模擬二層食物鏈的生態系統受農藥的影響。結果顯示，當毒性物質進入水體後，因攝食之食物來源減低與對於毒性的敏感度不同而致使魚群數目明顯下降。

關鍵字

生態風險評估 ； 農藥 ； 水體生態系統 ； 化學性危害

並列摘要

Abstract
Chemicals which are used to prevent crops from insect pests may pose a risk to the ecosystem. In the recent decade, the framework of ecological risk assessment has been applied worldwide to evaluate the potential impacts of anthropogenic pollutants on ecosystems. In this study we evaluated the ecological risks of four pesticides, carbendazim, benomyl, arbaryl, and dimethoate in aquatic environments, followed the USA ECOFRAM guideline. Investigation of pesticide contents in soils of applied croplands and a hypothetical pollution transport scenario were used to derive the expected environmental concentrations (EECs) of the four pesticides. Aquatic ecotoxicology database (ECOTOX) of USEPA was used as the references for the ecological risk criteria. Risks were characterized by the quotient method at the organism-level for the Tier 1 assessment and by the probability method at the community-level for the Tier 2 assessment.
The results showed that the risk of dimethoate has exceeded the threshold level suggested by USEPA and Tennessee regulatory practices. The ecological effect quotient (EEQ) of Tilapia nilotica and stonefly are 23.1 and 2.79, respectively. The community-level risk assessment shows that about 42% of aquatic species will be affected. Management measure should be taken to reduce the potential risk of dimethoate posed on the aquatic system. The other three pesticides, however, did not exceed the threshold values. To further examine the effect of predictor-prey interaction on the ecological risk of dimethoate, a simple population dynamic model with a food chain of zooplankton, and fish was constructed. The simulation suggested fish, the top trophic level organism, will suffer a larger decline in population upon considering preditor-prey interactions, than the solely toxicity effect.

並列關鍵字

ecological risk assessment ； pesticides ； aquatic ecosystem ； chemical hazard

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