台灣南部溪流中底泥金屬毒性描述與生態風險評估

Characterizing of Metal Toxicity and Ecological Assessment of Southern Taiwan River Sediments

巫欣澤(Shin-Che Wu)

指導教授 ： 謝季吟

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00250

摘要

利用平衡分配模式的酸揮發性硫化物(AVS)及同時提取金屬(SEM)分析進行台灣南部8條溪流(後勁溪、東港溪、鹽水溪、三爺溪、典寶溪、阿公店溪、武洛溪及牛稠溪)之底泥重金屬生物可利用性評估，並利用Hyalella azteca(10天全底泥及48小時孔隙水)進行水生生態系統危害程度(Tier 1、Tier 2及Tier 3)之毒性評估。同時使用化學評估及生物毒性試驗，來預測底泥或孔隙水之金屬毒性。
以ΣSEM-AVS數據評估結果顯示，典寶溪、三爺溪及阿公店溪風險程度均為Tier 1(即最高風險之不利影響)，後勁溪、牛稠溪及武洛溪風險程度為Tier 2，而鹽水溪及東港溪風險程度則為Tier 3。此外，ΣSEM/AVS及ΣSEM-AVS/foc結果與ΣSEM-AVS相似(以典寶溪、三爺溪及阿公店溪為最高風險)。全底泥毒性試驗方面，典寶溪、三爺溪、後勁溪及牛稠溪之存活率較阿公店溪、武洛溪、鹽水溪及東港溪低。此外，孔隙水急毒性試驗結果顯示，三爺溪及牛稠溪存活率最低。對Hyalella而言，孔隙水較全底泥試驗更具毒性，但孔隙水毒性可能因孔隙水中物理化學變化，導致不再與富含金屬的底泥顆粒接觸，故其試驗結果不能與全底泥試驗直接進行比較。
本研究顯示，三爺溪及牛稠溪為8條調查之溪流中污染最嚴重的兩條溪流，為瞭解引起毒性之污染物種類，未來應進行毒性鑑定評估。

關鍵字

生態風險評估 ； 金屬 ； 酸揮發性硫化物/同時提取 ； Hyalella azteca

並列摘要

Equilibrium partitioning models using acid volatile sulfide (AVS) were applied simultaneously with extracted metals (SEM) analyses to evaluate the bioavailability of heavy metals in sediments from eight rivers (Houjin, Donggang, Yanshuei, Sanye, Dianbao, Agongdian, Wuluo, and Niuchou) in southern Taiwan. In addition, their toxic effects were evaluated using the amphipod, Hyalella azteca (10-day for whole sediment and 48-hr for pore water), to assess the hazard level (Tier 1, Tier 2, and Tier 3) to aquatic ecosystems. A combination of chemical assessment and biological toxicity testing was conducted to predict the toxicity of metals in sediment or pore-water.
The use of ΣSEM-AVS showed that the Dianbbao, Sanye and Agongdian Rivers were in Tier 1, (i.e., highest risk for adverse effects). The Houjin, Niuchou, and Wuluo Rivers were in Tier 2, while the Yanshuei and Donggang Rivers were in Tier 3. Furthermore, ΣSEM/AVS and ΣSEM-AVS/foc results were similar to those of ΣSEM-AVS (higher risk found Dianbao, Sanye, and Agongdian Rivers). In whole-sediment toxicity tests, survival rates were lower in the Dianbao, Sanye, Houjin, and Niuchou Rivers than in the Agongdian, Wuluo, Yanshuei, and Donggang Rivers. In addition, pore-water acute toxicity testing showed that survival rates in the Sanye and Niuchou Rivers were low. Pore waters were more toxic to Hyalella than whole-sediment tests. However, pore-water toxicity tests were not directly comparable to whole-sediment testing due to the physicochemical changes in pore-waters no longer in contact with metal-rich sediment particles.

Our study revealed that the Sanye and Niuchou Rivers are two of the most contaminated rivers among the eight rivers investigated. Toxicity identification evaluations should be conducted in the future in order to understand the causative agents.

並列關鍵字

Hyalella azteca ； acid volatile sulfide/simultaneously extracted metals ； Ecological risk assessment ； metals

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