Effect of Imidacloprid, Chlorpyrifos and Azoxystrobin on Two Sediment Ecological Indicator Species (Amphipod and Chironomid)

• Main Authors: Chen-Kuang Tyan, 田晨光
• Other Authors: Jui-Hung Yen
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/ytxc68

碩士 === 國立臺灣大學 === 農業化學研究所 === 107 === In recent years, application of pesticide has been more common. For approving qulity of life, increasing the production and requirement of environment, these chemical materials have been used frequently and they almost were transported into the water ecosystem. Acute and chronic toxicity test of indicator organisms is an important way to assess the environmental risk of chemical materials. There are many creatures that living in water ecosystem. Their main habitats include water body and sediment. The organisms that are used in water ecosystem toxicity test in Taiwan are fish and daphnia, but they can only represent the non-target organism of water body. Chironomidae (Chironomus sp.) and amphipod (Hyalella azteca) are common sediment organism. As a decomposer, amphipods distribute widely in the fresh water in the world. As a predator, these creature are preyed by consumers from several levels, that makes amphipod become a irreplac eable species. Chironomidae is one of universal insect in water ecosystem that can effect different level of preyers in different life stage. Charactersistic that being a holometabolous species, short life cycle and observable chronic endpoint (emergence, biomass and sex ratio of adults), makes it become a rising indicator organism of sediment. These two species are explosed in imidacloprid, Chlorpyrifos and azoxystrobin for toxicity test. Lethal and sublethal (emergence and sex ratio) endpoint are observed during test duration. Half lethal concentration (LC50) of imidacloprid, Chlorpyrifos and azoxystrobin to H. Azteca are 24.4, 0.38 and 513.4 μg L-1, respectively, to Chironomus sp. are 19.4, 0.27 and 237.7μg L-1, respectively. Half effective concentration (emergence) of imidacloprid, Chlorpyrifos and azoxystrobin to Chironomus sp. are 0.107, 0.062 and 128.14 μg L-1, respectively. Sex ratio effected concentration (SEC) of three pesticide to Chironomus sp. are 0.074, 0.053 and 144.85 μg L-1, respectively. Comparing with toxicity data of water ecosystem from USEPA. Three pesticides are classified as high toxic for water organisms. Chironomus sp. that exposed in imidacloprid and azoxysrobin may affected during emergence stage and Chlorpyrifos may cause some impacts during pupa stage. Comparing data of pesticides residues in Taiwan’s main rivers with test data, concentration of residues are lower than LC50 of two species in these test. But concentration of imidacloprid’s and chlorpyrifos’ residues in river are higher than EC50 of emergence and SEC that shows these two pesticides environment may cause influence to non-targeted organisms in long run.