灌排不完全分離下水中懸浮固體是造成農田土壤重金屬累積的主要來源－以台灣彰化為例

THE SUSPENDED SOLID INDUCED IMPACT ON FARMLAND SOIL HEAVY METAL ACCUMULATION IN A DRAINAGE-CONVERGED IRRIGATION CHANNEL-IN CHANGHUA COUNTY, TAIWAN

林淳純(Chun-Chun Lin) ； 駱尚廉(Shang-Lien Lo)

《中國土木水利工程學刊》 35卷7期 (2023/11) Pp. 731-742

https://doi.org/10.6652/JoCICHE.202311_35(7).0010

摘要

自105年環保署對重點河段與農田引灌水源進行總量管制，並耗費20年完成全國農地污染改善，至今，水中重金屬已受到控制，定監數據卻發現農田土壤重金屬有增量。為避免污染再發生，本研究應用污染特徵、懸浮固體攔留器及所攔截的懸浮固體評估重金屬的輸入途徑與移動方式。結果顯示農田土壤與攔留器懸浮固體的重金屬污染特徵與皮爾森相關係數高，表示水中懸浮固體是造成農田土壤重金屬累積的主因。而灌溉水中懸浮固體的濃度隨著水流速度減緩而增加，渠道底泥厚度亦有相同趨勢，推論懸浮固體來自引灌水源，應從源頭管制以減低重金屬造成的可能風險。

關鍵字

農田土壤 ； 重金屬 ； 懸浮固體 ； 污染特徵 ； 引排水灌溉

並列摘要

After launching the total amount control in 2016 and finalizing a 20-year field pollution reduction program, heavy metal concentrations in the surface water are in control. However, regular monitoring still shows the increment of heavy metal concentrations in agricultural soil. To prevent pollution recurrence, this study aims to identify transportation media and routes of heavy metals by soil pollutant signature and intercepted suspended solids (SS). The result shows the high Pearson correlation coefficients of heavy metal concentrations in agricultural soils and intercepted SS, implying that the heavy metals of SS in irrigation water is the main contribution. Regarding the origin of SS in an irrigation ditch, SS increases while the water velocity decreases. On the other hand, the ditch sediment and SS have the same trend. Sedimentation-resuspension process well explains the relation, which implies the SS originates from the irrigation source. In order to lower the potential risks caused by heavy metals, our results further emphasize the importance of controlling the SS from the source.

並列關鍵字

heavy metals ； agricultural soil ； suspended solids ； pollution characteristics ； drainage-irrigated

參考文獻

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