應用GIS整合事業污染潛勢與灌溉渠道重金屬濃度—以新北市為例

Abstract

臺灣工商業發達，事業類別繁多。早期土地利用與都市規劃不完全，事業未經妥善管理，工業活動與農業生產相互爭奪土地資源。早年環保意識不足，事業廢污水放流路徑與農業灌溉渠道混合，導致渠道水體、底泥與周邊農地土壤面臨潛在重金屬污染風險，終將進入生物鏈，影響人體健康。為保護環境品質，同時增進行政效率，新北市政府環境保護局於2023年提出「事業污染潛勢地圖整合灌溉渠道預防管理作業」的發想概念，但整體架構仍有許多不足，因此本研究將以此為基礎，改良並建置一套簡化分析的方法。 本研究應用地理資訊系統 (Geographic Information System，GIS) 整合引用的資料，包含具污染潛勢事業分布、灌溉渠道水體、灌溉渠道底泥與周邊農地土壤之重金屬濃度監測結果，建置一套簡化分析的架構，並以視覺化呈現各界質重金屬濃度分布空間關聯性，供政府直觀快速識別可能污染來源與潛在污染熱區。 本研究領域為新北市轄內兩條灌溉渠道—二甲九圳、石頭溪圳，及其周圍灌溉農田，引用底泥及土壤背景重金屬濃度，再引用水質 (樹脂包)、底泥、土壤重金屬濃度，將各項環境濃度推估結果與事業污染潛勢圖堆疊圖層比較。研究結果顯示二甲九圳中游段及石頭溪圳下游段可以直觀辨識出鋅污染潛勢事業與各介質鋅濃度分布結果在空間上可能有高度關聯性，顯示本方法架構確實具有可行性，可供政府機關參考使用。但此方法仍受到許多條件限制，包含：1.源 (事業名單) 的完整性、2.流 (灌溉渠道) 的完整性及3.源、流、匯時空一致性，致使過往調查數據不易直接與現有資料連結。 建議政府機關優先針對事業密集的二甲九圳中游段及石頭溪圳中、下游段進行事業輔導，預防污染，針對二甲九圳下游段查證具鉛、鋅污染潛勢事業；石頭溪上、中游段查證具鋅污染潛勢事業。盡量補齊既有事業基線資料，造冊登記尚未掌握的非法事業。針對超標土壤及底泥辦理定期監測，同時針對渠道進行疏濬作業，已開挖底泥禁作其他用途。持續推動總量管制政策，增加劃定加嚴管制區，並希望能將本研究領域的兩灌溉渠道納入。未來若實施都市計畫，建議將事業分級分類，設置工業區集中管理。最後建議後人優化此架構，供中央機關實際應用分析。

Taiwan has a highly developed industrial and commercial sector with many different types of businesses. Due to incomplete land use planning and urban development in the past, industrial activities were not properly regulated, leading to competition for land between industrial and agricultural uses. In addition, weak environmental awareness in earlier decades allowed industrial wastewater discharge into agricultural irrigation channels. This may lead to heavy metal pollution in the water, sediment, and farmland soil. These pollutants may enter the food chain and pose risks to human health finally. To protect environmental quality and improve administrative efficiency, the Environmental Protection Department of New Taipei City Government proposed the concept of an “Industries Pollution Potential Map Integrated with Irrigation Channel Preventive Management” in 2023. However, the proposed framework remains incomplete. This study aims to build upon that concept by developing an improved and simplified analytical approach. This research applies Geographic Information Systems (GIS) to integrate referenced data, including the distribution of industries with pollution potential and monitoring results of heavy metal concentrations in irrigation water, channel sediment, and nearby farmland soil. A simplified analysis framework was constructed to visualize spatial relationships among environmental media and heavy metal concentrations, enabling the government to intuitively and efficiently identify potential pollution sources and contamination hotspots. The study area focuses on two irrigation channels in New Taipei City—RJJ-Channel and STS-channel—and the surrounding irrigated farmland. Background concentrations of heavy metals in sediment and soil were referenced, along with data on heavy metal concentrations in water (Ion Exchange Resin Packs), sediment, and soil. These environmental concentration estimates were then compared with the spatial distribution of pollution-prone industries through GIS layer overlays. The results show a clear spatial link between potentially zinc-polluting industries and high zinc concentrations in the midstream of the RJJ-channel and downstream of the STS-channel. This indicates that the proposed analytical framework is feasible and may serve as a useful reference for government agencies. However, the approach remains subject to several limitations, including: (1) the completeness of “source” data (i.e., industries lists), (2) the completeness of “flow” data (i.e., irrigation channel), and (3) the spatial and temporal consistency between “sources”, “flows”, and “sinks”. These limitations make it difficult to directly align historical monitoring data with current information. The study suggests that the government should focus on industry management and counseling industries to preventing pollution in the midstream RJJ-channel and the middle and downstream STS-channel. It should also investigate the potentially lead-polluting and zinc-polluting factories in the downstream RJJ-channel and potentially zinc-polluting industries in the up and middlestream STS-channel. Missing baseline data on industries should be completed, including illegal factories. Soil and sediment with high heavy metal levels should be monitored regularly, and dredged sediment should not be reused. The government should keep pushing Total Quantity Control (TQC) policies, expand TQC district, and consider including these two channels. Future city planning should classify and group industries into industrial park. Finally, future researchers are encouraged to improve this framework for practical use by Taiwan goverment.