X-射線螢光光譜儀快速篩測土壤重金屬取代王水法之探討

台灣目前以王水消化法作為土壤重金屬管制標準的全量分析方法，其分析較準確，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，現場即能快速篩選得知污染物濃度，但常受到樣品基質因水分或樣品不均質干擾，往往造成篩測數據與實驗室數據相關性不佳的情形。本研究為瞭解XRF快速篩測土壤重金屬樣品數據之可靠性與準確性，擇用台灣東、西區域場址土壤共120個樣品，除現地篩測XRF之外，再將受測之土壤重金屬樣品以土壤前處理方法，將之通過10mesh及100mesh標準篩網後再以王水消化法使待測金屬成為溶解性離子狀況，再以感應耦合電漿原子發射光譜儀分析鉻、銅、鎳、鉛、鋅等重金屬含量探討2種方法之差異。研究結果顯示土壤重金屬鉻、銅、鎳、鉛、鋅等5種元素在2種方法之結果有顯著的正相關性，除東場址鉻、銅、鎳等3種元素之前處理10mesh R2約0.82~0.85及東場址鎳元素之前處理100mesh 相關係數R2約0.87，其餘比較之相關係數R2皆達到0.9以上。

關鍵字

鉻；銅；鎳；鉛；鋅；王水消化法；重金屬

並列摘要

As a highly accurate quantitative method of determining the contents of heavy metal in soil, Aqua Regia digestion is a standard method in Taiwan, Digestion, a primary quantitative method, is accurate but a relatively high in cost and time consumption approach in deterimining the contents of heavy metals in soils. In contrast, X-Ray Fluorescence Spectrometer (XRF) is a lower cost and less time consuming method, However, the sample matrix is often affected by moisture or sample inhomogeneity, which often results in poor correlation between screening data and laboratory data. Heterogeneous disturbance in samples leads to poor correlations between measured and experimental data. This study explored the reliability and accuracy of X-Ray Fluorescence in rapid screening for heavy metals in soil. A total of 120 soil samples were acquired from Eastern and Western Taiwan. After the on-site X-Ray Fluorescence screening was completed, the samples were preprocessed and filtered through 10- and 100-mesh screens. The metals were converted to soluble ions through Aqua Regia digestion. Subsequently, inductively coupled plasma-atomic emission spectroscopy was employed to analyze the chromium, copper, nickel, lead, and zinc contents. A comparison of the two employed methods revealed a significant positive correlation between the measured and experimental data regarding the five studied elements. The R2 was 0.82~0.85 for the 10-mesh preprocessing results of chromium, copper, and nickel in Eastern Taiwan, 0.87 for the 100-mesh preprocessing result of nickel in Eastern Taiwan, and R2>0.90 for the remaining results.