- 學位論文
河川補注與生物整治對於地下水氯乙烯污染傳輸與健康風險之影響
Impact of River Recharge and Bioremediation on the Transport of Groundwater Vinyl Chloride Contamination and Health Risk
摘要
含氯有機物為地下水中常見的污染物之一，根據臺灣土壤及地下水污染整治網，臺灣至2023年6月地下水污染場址共有418筆，其中為含氯有機污染物的場址共有188處，由此可知臺灣地下水中含氯有機物的污染甚為嚴重，整治需耗費大量時間與經費，其污染危害也會影響到人類的健康風險。本研究案例為臺灣中部一含有氯乙烯污染場址，位於第一含水層有三口氯乙烯污染監測井，污染濃度較低，第二含水層有一口污染監測井，氯乙烯濃度超過管制標準88倍。本研究使用MODFLOW模擬地下水基本流場，搭配SEAM3D模擬氯乙烯污染傳輸，觀察第一含水層污染物自然降解的結果和污染團與河川之間的關係，第二含水層搭配健康風險評估討論整治前與整治後的差異。研究結果顯示位於第一含水層的污染團會受到河川季節變化影響，第二含水層污染團如透過生物整治工法與未整治相比可削減98.91%的氯乙烯濃度。後續搭配健康風險評估，第一含水層致癌風險低於10-6，非致癌風險小於1，皆在可接受範圍內，第二含水層整治前致癌風險為1.07×10-4，整治後致癌風險為1.18×10-6，與整治前相比下降了兩個數量級，非致癌風險均在可接受範圍內。
並列摘要
According to the Taiwan Soil and Groundwater Pollution Remediation Funds, organochloride contamination of groundwater, particularly in vinyl chloride (VC), stands as a prevailing issue. As of 2023, a significant number of sites, specifically 188 out of 418, were found to be afflicted with chlorinated organic pollutants, underlining the gravity of organochloride contamination in the groundwater of Taiwan. The contamination not only poses substantial risks to human health but also engenders a pressing concern for environmental safety. This study considers a case involving a VC contaminated site in central Taiwan. Within the first aquifer, three monitoring wells exist relatively low VC concentrations. Conversely, in the second aquifer, a contaminated monitoring well displays VC content that surpasses regulatory guidelines by a staggering 88-fold. In this study, the groundwater flow patterns are simulated using MODFLOW, while the dispersion of VC contamination is modeled through SEAM3D. The overarching objectives encompass observing the correlation between the contaminated plume and the adjacent river and assessing the natural attenuation of contaminants within the first aquifer. A comparative analysis before and after treatment is undertaken in the second aquifer, accompanied by a comprehensive health risk assessment. The simulation results underscore the discernible influence of seasonal river fluctuations on the pollutant plume within the first aquifer. In contrast to untreated conditions, bioremediation demonstrates the capacity to curtail the pollutant plume within the second aquifer by a noteworthy 98.91%. Furthermore, a health risk evaluation reveals that the carcinogenic risk within the first aquifer falls below 10-6, while the non-carcinogenic risk remains under 1 both figures adhering to tolerable limits. Before remediation, the second aquifer bears a carcinogenic risk of 1.07×10-4, yet post-remediation, this risk diminishes significantly by two orders of magnitude, settling at 1.18×10-6 from the original 1.07×10-4. In both scenarios, non-carcinogenic risks stand at levels deemed acceptable. In light of these outcomes, it becomes evident that the study holds implications of paramount significance, shedding light on the complex dynamics of organochloride contamination remediation. These findings extend the horizons of effective groundwater management, emphasizing the potential of bioremediation in mitigating health and environmental risks associated with organochloride contamination in Taiwan.