河川及其出海口海域毒性污染物分佈與牡蠣生物累積關係之研究

Correlation between Toxic Pollutants Distribution of Contaminated River or Estuary and Bioaccmulated Oysters

石偉成(Wei-Cheng Shih)

指導教授 ： 林錕松

元智大學/工程學院/化學工程與材料科學學系/碩士(2007年)

https://doi.org/10.6838/YZU.2007.00266

摘要

近年來，人工養殖牡蠣為台灣西部近海重要水產品之一，但工業的發展與廢水不當的排放，造成台灣部分地區所養殖的牡蠣體內部分重金屬含量已達世界級水準，因此，本研究以台灣西北部沿海都市為研究區域，調查因工業發展及高科技園區設置，產生之污染物對環境之水質、沉積物及養殖長牡蠣(Crassostrea gigas)的影響。

本論文之調查及分析實驗部分主要包括：地區環境背景歷史(2003年9月至2006年11月)資料收集及海域水質、沉積物與養殖區長牡蠣(2004~2006)之歷史資料收集採樣。實驗分析部分，現場進行水溫、鹽度測定；另水質、沉積物及養殖區所採集之牡蠣樣品，分別於實驗室分析其重金屬含量（銅、砷、鋅、鎘、鉻及鉛）及揮發性有機物(Volatile Organic Compounds)、同步輻射光譜(XANES/EXAFS)、傅立葉轉換紅外線光譜(FTIR)等。

研究發現客雅溪河床土壤與植物吸收環境中重金屬並累積，使出海口水質與沉積物中銅離子關連性較不明顯，但出海口沉積物中，銅離子仍有一定程度之濃度分佈，顯示工業含銅廢水對流域水質與沉積物仍造成影響。調查發現三姓溪河道為水泥加封之複式段面，其溪水未接觸土壤、植物及水塘等能讓重金屬沈降、吸附之環境，且中、下游河段工業，對其銅離子供應大於其他河段，亦可能是沿海沉積物重金屬主要來源之一。由沿海沉積物研究結果，銅富集因子平均為2.4、鋅平均為6.51、鎘平均為5.23、鉻平均為1.74及鉛平均為10.92。顯示沉積物各重金屬確有明顯富集及人為污染，其中尤以鋅、鎘及鉛之富集現象最為明顯。研究發現2005年8月期間因沉積物中鋁濃度異常增加，使富集因子計算結果異常，經查為當時期酸雨淋洗土壤將鋁化合物溶出，並經水環境傳輸後沉積所致。

養殖牡蠣體內銅濃度變化為103~1409 ppm，由生物濃縮因子研究發現，與客雅溪及三姓溪之水質關連性高，尤以客雅溪為其主要供應來源，並隨降雨量變化，使春季牡蠣體內銅離子含量達最高峰，最低為夏季，平均濃度由2006年4月之470.6 ppm下降至2006年7月之195.5 ppm，而生物濃縮因子於4月份之4.56×105降為9.0×104。另砷濃度變化亦與氣候降雨有關，其主要以水質與三姓溪沈積物吸收為其來源，惟研究發現牡蠣吸收環境中砷之方式較無特定依循，且嗜砷性低，排砷性高。另鋅濃度變化為107~722 ppm，其生物濃縮因子介於2.66~5.11×104之間，其由水環境所供給高於沈積物所提供，且供給不虞匱乏。研究發現銅、鋅於牡蠣體內呈同步變化，但牡蠣體對銅離子的排出能力低於鋅離子，其他重金屬如鎘、鉻及鉛等在牡蠣軟組織濃度含量均相當低。研究發現牡蠣外殼重金屬濃度變化，枯水期高於豐水期，明顯與季節有關，且砷、鉻離子與其他重金屬相比較，其於牡蠣殼及軟組織內濃度含量相差數倍，為該元素特性。

養殖區沉積物及牡蠣軟組織揮發性有機物分析，發現微量甲苯，其濃度與影響由物質安全資料表可確認，適量食用牡蠣而造成甲苯中毒之影響應該微乎其微。另傅氏紅外線光譜分析牡蠣軟組織，結果為氨基酸及甲苯可能性最大；而沈積物分析結果，應為碳氫化合物及水可能性為最大。另由X光吸收邊緣結構光譜(XANES)實驗數據分析發現，牡蠣軟組織中銅離子，部分與有機硫鍵結（可能是硫醇類)方式存在。

關鍵字

牡蠣 ； 重金屬 ； 富集因子 ； 生物濃縮因子 ； 揮發性有機物 ； 同步輻射光譜

並列摘要

Recently, the artificial cultivation of oysters (e.g. Crassostrea gigas) has become important aquatic products around west coastline of Taiwan. Due to the industries development and industrial wastewater, the amount of heavy metals in oysters cultivated in some area of Taiwan has become very significant compared to other areas of the world. Therefore, the present study has selected cities around northern west coastline area of Taiwan, where the industries are well developed. In addition, Hi-tech Science Parks are also sited as sampled district to investigate the pollution impact of water quality, precipitate contamination in stream, and aquatic lives.

Experimentally, collecting environmental background data from September 2003 to November 2006, analyzing of marine water quality, sediment contamination, and Crassostrea gigas (2004~2006) were conducted. The analytical experiments including in situ measurement of water temperatures, salinity, analyses of the heavy metals (Cu, As, Zn, Cd, Cr, and Pb) in streamwater, stream precipitates or oyster shell by ICP/MS, volatile organic compounds concentration of streamwaters, precipitates or tissues of Crassostrea gigas by GC/MS, fine structures of metal ions in oyster tissues by XANES/EXAFS, and FTIR were also performed.

The heavy metals were absorbed and accumulated in soils and plants in Ke-Ya stream, but the correlation between Cu ions and estuary water quality is low found in the present study. However, the Cu ion concentration in soil is still at a certain level around estuary area, it reveals that the industrial Cu-contaminated wastewater still influence the stremwaters and stream precipitates concentration. The San-Xing stream with cemented river bank, and the streamwater does not come into contact with soil, plant and ponds to settle down or absorb heavy metals. Copper ion generated from the industrial discharge at middle- and down- stream was higher than other sections of the river and may be the major heavy metal sources. According to the experimental result on precipitates, the averaged enrichment factor of Cu ions was 2.4 and Zn (6.51), Cd (5.23), Cr(1.74) or Pb element was 10.92, repectively. The result proves both the enrichment phenomenon of heavy metals and artificial pollution, especially Zn, Cd, and Pb ions with the most obvious enrichment phenomenon. The abnormal increasing of Al concentration in sediment in August 2005 and the calculation of abnormal enrichment factor as well were found. It indicated that the Al compounds was leached out by acid rains and deposited during the water transferring processes.

The Cu concentration of artificial cultivated Crassostrea gigas was from 103 to 1409 ppm, and it is closely correlated with the water quality of both Ke-Ya and San-Xing streams. However, Ke-Ya stream is the major source of the contaminants in oysters. The Cu concentration related to the precipitates of Crassostrea gigas reached the highest value in spring and the lowest one in summer. The averaged concentration decreased from 470.6 ppm (April, 2006) to 195.5 ppm (July, 2006) and the bioaccumulation factor decreased from 4.56×105 to 9.0×104 in April, 2006, respectively. The changes on As concentrations were also related to polluated precipitates. The major sources of As are from water and precipitates of San-Xing stream. There is no specific way for the Crassostrea gigas to absorb As in the environment, and it is As-phile rather than As-repelling. The Zn concentration of Crassostrea gigas was from 107 to 722 ppm, its bioaccumulation factor was between 2.66 and 5.11×104. This result showed that the very sufficient supply of Zn ions was from aquatic environment eventually. The Cu and Zn ion in Crassostrea gigas tissues having the same consistency was observed. The average concentration of Cu ions was lower than Zn ones in the tissues of Crassostrea gigas. The concentrations of Cd, Cr and Pb ions in the tissues of Crassostrea gigas were quite low. In addition, the concentration variation of Crassostrea gigas shell was highly related to the seasonal difference during 2006. Compared As and Cr ions with other heavy metals, the concentration difference in shell and soft issue of Crassostrea gigas is several times due to their elemental characteristics.

According to our analyses of VOCs concentration in Crassostrea gigas and precipitates from breed area, toluene was detected with a very low concentration. Consulting with the MSDS data, it is unlikely to cause toluene poisoning by appropriately intake of the oysters. The FTIR analyses of Crassostrea gigas tissues, the highest possibility was amino acid of protein and toluene. In terms of precipitate analyses, the most possible species were hydrocarbon compounds and water. However, there are some correspondings to the VOC analyses. Based on the analyses of X-ray absorption near edge structure spectra (XANES), the Cu ion in Crassostrea gigas is partially bonded to postulated organic sulfur (Cu-S) of thiol.

並列關鍵字

Oyster (Crassostrea gigas) ； Heavy metals, Enrichment factor ； Bioaccumulation factor ； Volatile organic compounds ； XANES/EXAFS

參考文獻

41.行政院環境保護署環境檢驗所，NIEA R409.21C (2006)。

74.行政院環境保護署環境檢驗所，NIEA W424.51A (2006)。

75.行政院環境保護署環境檢驗所，NIEA W217.51A (2006)。

76.行政院環境保護署環境檢驗所，NIEA W308.22B (2006)。

77.行政院環境保護署環境檢驗所，NIEA W306.52A (2006)。