| Summary: | 碩士 === 國立高雄師範大學 === 生物科技系 === 95 === Gao-Ping River has the largest watershed area in Taiwan with population of 2.7 million around Kaohsiung and Pingtung area. The objective of this study is to evaluate the currently water quality and risk posed by contaminants in Gao-Ping River. With the enacting policy of downsizing concentrated animal feeding operation in the watershed areas, compare of ecological risk was made to evaluate the effectiveness of the policy.
This result shows that among Gao-Ping River’s branches, the Wu-Luo River’s pollution, is the most highly contaminated. In risk assessment, potential risk of ammonia exposure was greatest. However, compared with the time before the policy of downsizing concentrated animal feeding operation, both acute and chronic risks dwindle apparently. Copper and zinc posed the higher ecological risk among metals, which demonstrates little difference comparing to ecological risk assessment conducted in 2002. The risk of heavy metals in the wet season is higher than that in the dry season. The risk of ammonia in dry season is lower than that in wet season, showing that the amount of water in wet season does not cause the dilution effect of heavy metal concentration. Meanwhile, organic pollutants posed negligible risk. In terms of risk addition, under the current condition of water quality. In dry season, 50% of the time, 31% of the species would affected by the acute risk and 92% of the species would affected by the chronic risk. In wet season, 50% of the time, 26% of the species would affected by the acute risk and 87% of the species would affected by the chronic risk. The study indicates the change of water quality and ecological risks with implementation of policy to remove concentrated animal feeding. The results will provide decision makers for establishing policy of future river restoration.
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