桃園及彰化二地共四種土壤中之重金屬(鎘與鋅)分別以0.1 M HCl,ammonium acetate acetic acid ethylene diaminetetraacetic acid(AAAC)及HClO4-HF三種不同方法抽出。與0.1 M HCl抽出相比較,AAAC緩衝液抽出較多的鎘及鋅;果也顯示,桃園及彰化受污染區土壤中鎘的總量分別為13.6及10.6 mg Cd kg-1 soil,此說明未受污染之土壤樣品,其原有之鎘含量均在安全範圍之內。鋅的濃度以彰化污染區最高,達1195 mg Zn kg-1 soil-1,但桃園土壤並未達到鋅污染的標準。連續萃取實驗顯示所選取樣區土壤中的鎘主要都是可以交換的形態存在。桃園地區土壤中的鋅主要是可交換及氧化物鍵結部分,而彰化地區土壤鋅則主要存在於碳酸鹽類和氧化物鍵結部分。
The heavy metals, i.e., Cd and Zn, in the Taoyuan and Changhua county soils were extracted by 0.1M HCl, ammonium acetate acetic acid ethylene diaminetertraacetic acid (AAAC), and HClO4-HF. Compared to0.1M HCl, AAAC extracted more Cd and Zn from the sample soils. Total Cd (extracted by HClO4-HF) in the contaminated Taoyuan and Changhua soils are 13.6 and 10.6 mg Cd kg-1 soil, respectively, but it is lower than 1 mg Cd kg-1 soil in the non-contaminated soils. The results indicate that these native soils are not polluted by Cd. Highest Zn concentration (up to 1195 mg Zn kg-1 soil) was found in the contaminated Changhua soil. However, the Zn concentrations in the Taoyuan soils are within acceptable range. Sequential extraction experiments showed that Cd in both soils is mainly exchangeable. Exchangeable and oxides bonded Zn are two major species in the Taoyuan soils. Zinc was associated with carbonate and oxides in the Changhua soils.