利用底泥毒性鑑定評估進行農業區溪流底泥相關污染物確認

Species confirmation of sediment-associated contamination in river located on agricultural area by sediment toxicity identification evaluations

林立芳(Lin Li-Fang)

指導教授 ： 謝季吟 ； 余伍洲

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2019年)

https://doi.org/10.6346/NPUST201900386

摘要

農業生產為國家之重要產業，影響著國內的糧食供應及經濟發展，農民為了提高農產品的銷量及品質，廣泛使用殺蟲劑於害蟲防治，然而殺蟲劑的不當使用也將對環境及生物或人類帶來危害性，更可能具有難以復原的生態風險。殺蟲劑可透過不同途徑進入環境中，亦可能殘留於土壤、水體及底泥，其中底泥為許多底棲生物棲息之場所，亦為溪流水體潛在污染來源。因此，本研究利用底棲無脊椎端足目動物(Hyalella azteca)作為底泥生物毒性試驗物種，篩選武洛溪(GL1~GL3)及大湖圳(LL1~LL3)污染底泥進行毒性試驗，運用全底泥(whole sediment)及孔隙水(porewater)毒性鑑定評估(Toxicity Identification Evaluations, TIE)程序描述和鑑定水體底泥的可能毒性來源。藉由實驗結果計算Hyalella azteca暴露於含有污染物底泥的存活率，評估受污染底泥毒性對生態系統的影響，以探討農業發展導致水體污染蓄積於底泥後所可能導致的生物效應，是否可能透過食物鏈產生生物累積或生物放大作用對生態環境或生物體造成衝擊。本研究結果顯示第一批樣品採樣時樣站LL1、LL3、GL1、GL2、GL3及第二批樣品採樣時樣站GL1的毒性來源可能為Ethion，添加胡椒基丁醚(Piperonyl Butoxide,PBO)會降低其毒性；第一批樣品採樣時樣站LL3、GL1、GL2、GL3及第二批樣品採樣時樣站GL1、GL3毒性來源可能為Lambda-cyhalothrin，添加羧酸酯酶(Carboxylesterase)會降低其毒性。而第二批採樣之底泥孔隙水樣品中，各樣站毒性來源可能為合成除蟲菊精類以外之物質，Lambda-cyhalothrin濃度可能會因添加羧酸酯酶而降低。由於Lambda-cyhalothrin及Ethion具有較高之辛醇水分配係數，為脂溶性污染物，因此相較於底泥樣品，於孔隙水中分析出較低之濃度。總體而言，環境底泥及孔隙水樣品中不同類別的化合物和毒性之間存在顯著相關性，但這些相關性並不代表兩者和毒性之間存在著直接的因果關係，包括存在於底泥中有機碳和孔隙水萃取流程中會改變底泥動態平衡都可能是影響毒性的因子，由於全底泥和孔隙水TIE研究的底泥毒性不同，使用兩種TIE方法分別進行風險評估，未來也將探討其相關性，可提供底泥毒性更準確的風險評估。
關鍵字：Hyalella azteca、Lambda-cyhalothrin、Ethion、毒性鑑定評估、全底泥、孔隙水

關鍵字

Hyalella azteca ； 孔隙水 ； 毒性鑑定評估 ； 全底泥 ； Ethion ； Lambda-cyhalothrin

並列摘要

【Abstract】
Farmers use pesticides widely to reduce the numbers of harmful insects in order to increase the volume and quality of agricultural products. However, pesticide abuse presents a danger to the environment, its animals, and people. What is more serious is that ecological systems may be harmed and not recover. Pesticides are used in different ways in the environment, and persist in soil, water, and sediment. Especially, sediment is a biological habitat and source of water pollution. This research used Hyalella azteca as representative biological organism for sediment toxicity testing. In order to describe and identify possible sources of toxicity for water and sediments via Toxicity Identification Evaluations, we chose whole sediments and porewaters from the Wuluo River (GL1~GL3) and Dahu Canal (LL1~LL3). Through experiment, we calculated how the toxicity from sediment accumulated by polluted water affected the survival rate of Hyalella azteca and the overall biological system, and whether the biological environment was impacted through the food chain or by biological magnification. Our research show that the toxicity in the first (LL1, LL3, GL1, GL2, and GL3) and second sampling stations (GL1) is from Ethion. Adding PBO can reduce this toxicity. We show that toxicity also occurs from Lambda-cyhalothrin in the first (LL3, GL1, GL2, and GL3) and second sampling stations (GL1). Adding a carboxylesterase can reduce this toxicity. Toxicity in the second sampling station’s porewater also derives from a pyrethroid. The concentration of Lambda-cyhalothrin is reduced by adding a carboxylesterase. Because lambda-cyhalothri and Ethion have a higher Kow (Octanol-Water Partition Coefficient), it represents a liposoluble pollution. Therefore, porewater analysis exhibited a lower concentration compared to sediment. Overall, the samples of sediment and porewater had obvious correlations between different chemical compounds and toxicity. These correlations do not mean that toxicity is directly caused by a combination of sediment and porewater. The extraction of organic carbon from sediment and porewater changed the dynamic equilibrium of the sediment’s influence on toxicity. Because the TIE research showed that sediment and porewater have different toxicities, both of them should undergo TIE risk assessments. Their correlation will be discussed in the future to supply a more accurate risk assessment.
Keywords：Hyalella azteca、Lambda-cyhalothrin、Ethion、Toxicity Identification Evaluations、whole sediment、porewater

並列關鍵字

Hyalella azteca ； porewater ； Ethion ； Lambda-cyhalothrin ； Toxicity Identification Evaluations ； whole sediment

參考文獻

Abernathy, C. O. and Casida, J. E., 1973, "Pyrethroid insecticides: esterase cleavage in relation to selective toxicity," Science, Vol. 179, No. 4079, pp. 1235-1236.

Adams, W., Green, A., Ahlf, W., Brown, S., Burton, G., Chadwick, B., Crane, M., Gouget, R., Ho, K., and Hogstand, C., 2005, "Using sediment assessment tools and a weight of evidence approach," Use of Sediment Quality Guidelines and Related Tools for the Assessment of Contaminated Sediments. Society of Environmental Toxicology and Chemistry, Pensacola, FL, USA, No. pp. 163-225.

Adams, W. J., Blust, R., Borgmann, U., Brix, K. V., DeForest, D. K., Green, A. S., Meyer, J. S., McGeer, J. C., Paquin, P. R., and Rainbow, P. S., 2011, "Utility of tissue residues for predicting effects of metals on aquatic organisms," Integrated Environmental Assessment and Management, Vol. 7, No. 1, pp. 75-98.

Aidridge, W., 1953, "Two types of esterase (A and B) hydrolysing p-nitrophenylacetate, propionate and butyrate, and a method fortheir determination," Biochem J, Vol. 53, No. pp. 110-7.

Aldridge, W., 1993, "The esterases: perspectives and problems," Chemico-biological Interactions, Vol. 87, No. 1-3, pp. 5-13.