台灣目前以王水消化法作為土壤重金屬管制標準之全量分析方法,其分析雖準確,但相對的也較昂貴、耗時。近年X-射線螢光光譜儀(以下簡稱XRF)常被應用於重金屬污染土壤現地快速篩測方法,其分析時間短且經費低。本研究擇用台灣東部區域含有高濃度的鉻、鎳等重金屬之蛇紋岩土壤(共294個樣品)及台灣某區域受重金屬污染之農地土壤(共127個樣品)為試驗樣品,進行鉻與鎳等重金屬濃度檢測分析,並以統計方法探討王水法與XRF所檢測重金屬濃度之差異性。 研究結果顯示農地鉻及鎳含量以王水法及XRF間具有高度相關性,R2值分別為0.95與0.98(P<0.01),但對蛇紋岩鉻相關性較低(R2=0.64,P<0.01),而鎳亦具有高度相關性(R2=0.94,P<0.01);分析濃度以農地土壤的鉻XRF法略低估王水法,但鎳XRF高於王水法,而蛇紋岩鉻及鎳XRF遠高估王水法。因此XRF應用於農地鉻、鎳調查可大幅減少王水法實測樣品數,並降低土壤重金屬檢測分析費用。
As a highly accurate quantitative method of determining the contents of heavy metal in soil, aqua regia digestion is a standard method in Taiwan, and the control standards of soil in Taiwan is primarily based on this method. X-ray fluorescence spectrometer (XRF) is a fast and low cost screening method widely used in situ for real-time investigation approach. 294 high concentration soil samples (Cr & Ni) formed from serpentine in east Taiwan and 127 contaminated samples from rice paddy were analyzed in both aqua regia deigestion and XRF methods. The results were compared and discussed using statistical method. The results of both methods were highly correlated in rice paddy samples ( R2=0.95 and 0.98, P<0.01). In contrast, the correlation of Cr concentration in serpentine soil samples were not significant (R2=0.64, P<0.01) whereas the conc. of Ni were highly correlated (R2=0.94, P<0.01). Concentration of Cr in rice paddy samples is under estimated with XRF methods while the Ni is over estimated. In the case of serpentine soil samples, XRF method is over estimated in both elements. Consequently, the application of XRF screening method in the investigation of contaminated rice paddy could largely decrease the amounts of laboratory analysis, and thus reduce the cost.