臺灣農地重金屬高污染潛勢區域篩選方法之探討

The Investigation of Screening Methods for Agricultural Land with High Potential of Heavy Metal Pollution in Taiwan

洪美秀(Mei-Shiou Hung)

指導教授 ： 張尊國

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.00852

摘要

土壤是人類生存的基本資源，更是農業發展的重要基礎。臺灣農地受重金屬污染主要是長期引用受工業廢水污染之灌溉用水所導致。歷年來，環保與農政單位針對農地重金屬土壤調查係以網格式進行，因不考慮污染傳輸之空間脈絡概念，導致無法掌握農地土壤污染與引灌水源之間的相關性。本研究篩選機制為系統性篩選法，奠基於污染傳輸脈絡，故以水利小組為評析空間單元，配合內梅羅綜合指標為依據進行評價分級，並利用空間自相關法找出熱區（H-H）；此外，加入非系統性污染之極端值篩選法，以完備全臺農地污染潛勢區域之分析。為證明篩選機制之正確性及適用性，以過去歷史土壤調查資料，利用空間自相關分析及實際調查資料加以驗證。其目的希冀建立一套農地重金屬污染評價架構，以更有系統性之分析方法，找出農地重金屬高污染潛勢之區域。
研究結果顯示，全臺農地重金屬高污染潛勢區域約6,800公頃，嚴重污染區主要位於桃園縣、臺中市、彰化縣及高雄市。驗證結果得知，本篩選機制以水利小組作為農地污染評量之最小單元，為適切且極具效率。由採樣調查資料驗證結果顯示，屬於危害及污染等級水利小組內之農地超標機率分別為40.3%與29.2%，警戒、安全及優良等級之超標機率分別為13.2%、4.9%及1.0%，故建議以污染及危害等級之水利小組為後續優先調查區域。
土壤中重金屬污染不論對環境、農作物品質甚至經濟層面皆造成極大之衝擊，也可能直接或間接危害人體健康。因此，藉由本研究之篩選機制可有效鎖定污染區，並提供政府單位有效地執行農地污染調查及復育作業。

關鍵字

農地 ； 土壤重金屬 ； 篩選機制 ； 內梅羅指標PN ； 空間自相關分析

並列摘要

Soil is an essential resource for human survival, and is the foundation for agriculture. In Taiwan, heavy metal pollution of agricultural land was mainly caused by irrigating water contaminated by industrial discharges. Grid sampling is the standard procedure when soil surveillance was carrying out by environmental protection and agricultural authorities for agricultural land. However, in this way there is lack of the connection between the pollutant and the pathway of irrigation system. In this study, the systematic pollution screening process was developed based on irrigation group as unit, each unit evaluated and grading by Nemerow index and when PN＜0.7 classified as health area, 0.7≦PN＜1.0 classified as safe area, 1≦PN＜2 classified as slightly polluted area, 2≦PN＜3 classified as moderately polluted area, and PN≧3.0 classified as seriously polluted area. Meanwhile, use spatial autocorrelation method to identify in the hot spot areas. For the upland outside the irrigation area, using the extreme value method to identify pollution sites in order to complete the analysis of agricultural land as the whole. To verify the applicability of screening method, case study was performed and discussed.
The results showed that the high potential of heavy metal pollution in agricultural land is approximate 6,800 ha in Taiwan, mainly located in Taoyuan County, Taichung City, Changhua County and Kaohsiung City. The results also showed that the rate of exceed of contamination standard were 40.3% in PN≧3.0 seriously polluted area and 29.2% in 2≦PN＜3 moderately polluted area, and 13.2% in slightly polluted area , 4.9% in safe area and 1.0% health area.
Soil heavy metal pollution not only affects the crop quality, social economic, but also threatens human health. As a result, with this proposed screening method can effectively target the contaminated area and provide government agencies to effectively enforce agricultural land investigation and restoration.

並列關鍵字

agricultural land ； heavy metals ； screening method ； pollution index PN ； spatial autocorrelation analysis

參考文獻

4. 江季亭(2011)。環境中重金屬污染與口腔癌之關聯探討。國立臺灣大學生物環境系統工程學系博士論文。

8. 行政院環境保護署(2002)。農地土壤重金屬調查與場址列管計畫。

9. 行政院環境保護署環境檢驗所(2005)。環境採樣規劃設計。

2. 行政院環境保護署網站：http://www.epa.gov.tw/

53. 薛益忠、郭士鳳(2010)。利用「空間自相關」探索1999年至2005年臺灣腸病毒病例之空間擴散。華岡地理學報，25，37-52。