EPA-99-GA13-03-A199

099

1,980 千元

2010/09/28

2011/09/27

柯淳涵

土污基管會

謝菊蕙

台灣大學

土壤及地下水

重金屬污染、植生復育、樟樹

heavy metal pollution, phytoremediation, campor tree

王義仲

楊秉元

02-33664653#

r99625043@ntu.edu.tw

本計畫自民國99年9月28日起，針對桃園縣蘆竹鄉中福地區之重金屬污染之農地，探討以造林植生復育法對重金屬污染改善之效益。進行受重金屬污染農地之土壤重金屬含量，及其林木之重金屬含量與總生物量分析。本計畫一共調查5筆造林地 (地號為99-13、103、152-1、152-2及162，總計2.09公頃)，及5筆植草地 (地號為116-1、158-1、158-2、158-6及102-5，總計0.7461公頃)，目前已完成35筆採樣點表土 (0-15公分)及裡土 (15-30公分)等之土壤重金屬濃度分析，包含砷、鎘、鉻、銅、汞、鎳、鉛、鋅等及土壤基本性質分析。並分析造林地5個地號林木 (以樟樹為主)之植體重金屬含量 (包含葉部、枝條、心材及邊材)及總生物量，另外比較計畫目標地，以實施造林與完成整治復耕後進行稻米生產之經濟效益分析。 在土壤重金屬結果方面，在完成分析之中福地區中，主要污染項目為鎘(Cd) ，全部平均為3.86 mg/kg (0.14~15.5 mg/kg)，其中超過土壤重金屬污染管制標準之樣品有11筆(5.29~15.5 mg/kg)，超過土壤重金屬監測標準之樣品有9筆 (2.54~4.8 mg/kg)。與2003年桃園縣政府環保局的歷史數據 (重金屬鎘的值為0.53~25.8 mg/kg之間)作比較，造林地土壤鎘的平均含量從2003年的6.08 mg/kg降至2.98 mg/kg；植草地土壤重金屬數據，鎘的平均含量從2003年的8.45 mg/kg降至5.54 mg/kg。上述數據與2003年桃園縣政府環保局的歷史數據做比較，雖然從平均值來看，造林地的鎘濃度下降的情形比植草地來的高，然而統計上並無顯著差異。 植體重金屬含量方面，主要污染項目為鎘 (Cd)，其次為鉻 (Cr)，葉部鎘含量為0.79~8.97 mg/kg之間，枝條鎘含量為1.28~15.4 mg/kg之間，邊材鎘含量為0.64~10.6 mg/kg之間，心材鎘含量為0.53~3.08 mg/kg之間，以各別單株來看，枝條的單位鎘含量最大，其次依序為葉部、邊材、心材。初步分析顯示，此處生產木材可作為木棧道、步道材料，或經塗裝後作為家具用材。然而溶出試驗並無重金屬檢出，因此亦可作為一般廢棄物處理，或作再生能源。 在植草地及造林地土壤基本性質分析結果顯示，同一地區所採之兩種土壤性質沒有太大的差異。建議造林樹種為土壤適應力強之相思樹、白雞油和印度紫檀等。 本計畫彙整中福受重金屬污染2.089公頃造林農地，若實施整治所需成本約為485萬元，經過20年之後稻米收益合計僅為92萬元。若參加林務局平地造林計畫，在20年後此處污染農地的補助扣除造林成本將達376萬元收入，若參加環保署污染農地造林計畫，每10年此處污染農地的補助扣除造林成本將達165萬元收入。環保署的造林補助為對象為農地經環保機關公告為「土壤污染控制場址」，而造林補助為10年期，但樹木是需經長時間的生長，因此兩種造林補助計畫的整合仍需進一步的討論。除上述補助外，在20年後收益若為木材處分約為30萬元，而收益若為出售全株樹木作景觀用，將達355萬元，然而景觀樹木的銷售推廣需要政策上的鼓勵，以提高未來農民參與之意願。本計畫已辦理3場次推廣宣導會，以推廣環保署農地土壤污染控制場址停耕補償補助原則及處理農地污染事件標準作業原則，以利受污染農地之農民瞭解環保署之相關補助與農地處理原則。

重金屬污染、植生復育、樟樹

EPA99GA1303A199.pdf

20MB

2012/2/1 上午 12:00:00

Started from September 28, 2010, this project investigated the benefits of phytoremediation by the afforestation for remediation of heavy metal polluted farmlands in Chung-Fu area, Lu-Chu township, Tao-Yuan county. Heavy metal contents of soils of polluted farmlands and woody biomass on the planted trees were measured, as well as overall woody biomass. Five afforestation plots (nos. 99-13, 103, 151-1, 152-2, 162, with total area of 2.09 ha) and five grass plots (nos. 116-1, 158-1, 158-2, 158-6, 102-5, with total area of 0.746 ha) have been analyzed for heavy metal contents of top (0-15 cm) and inner layer (15-30) soils, as well as their fundamental properties. 35 soil samples were analyzed for their heavy metals contents including arsenic, cadmium, chromium, copper, mercury, nickel, lead and zinc. Total woody biomass, mainly composed by camphor, was also estimated. The economic benefits for afforestation and the scenario of rice production after remediation were also estimated. Cadmium (Cd) was found to be the major pollutant among the heavy metals in Chung-Fu area. The averaged concentration was 3.86 mg/kg, with the range of 0.14~15.5 mg/kg. There were 11 samples found at 5.29~15.5 mg/kg in the soil, exceeding the control standard. Cd concentrations of 9 soil samples were found at 2.54~4.8 mg/kg, exceeding the monitoring standard. The averaged Cd concentration of forested soils was reduced from 6.08 mg/kg in 2003 to 2.98 mg/kg in this study. The averaged Cd concentration of soils of grasslands was reduced from 8.45 mg/kg in 2003 to 5.54 mg/kg in this study. The Cd contents of soil samples measured by Taoyuan county government in 2003 were 0.53~25.8 mg/kg. However, the difference the Cd contents between the results of this study and of the aforementioned 2003 study were found insignificant by statistical methods. For plant biomass analysis, Cd and Cr were the two major contaminants. 0.79~8.97, 1.28~15.4, 0.64~10.6 and 0.53~3.08 mg Cd/kg dried biomass were found in the leave, branch, sapwood and heartwood samples. Averaged Cd contents of the branches in the individuals were found larger than the values in the leaves, sapwood and heartwood. Initial analysis revealed that the wood produced by the studied sites could serve as wood trestles, trail steps and furniture materials after furnishing. In addition, there was no leaching for heavy metals after TCLP tests. Hence, the wood also could serve as general fuels. There are not a lot of differences of fundamental properties for soils in grass plots and forested plots. Based on their better soil adaptabilities, the acacia, the white chanterelle, Indian rosewood and thorn bamboos are recommended for plantation in the environments of the studied sites. This study estimated that the remediation cost for the 2.089 acre heavy metal polluted farmlands in Chung-Fu area was 4.85 million NTD. Averaged net income for 20 years of rice plantation was only 0.92 million NTD. 376 million NTD was expected for landowners enrolled for the plain afforestation plain of Taiwan Forest Bureau after 20 years. 3.76 million NTD of subsidy was expected for landowners enrolled for the plain afforestation plain of Taiwan Forest Bureau after 20 years. 1.65 million NTD of subsidy per acre was expected for landowners of polluted farmland enrolled for the plain afforestation plain of Taiwan EPA after 10 years. Only farmlands declared as the polluted control sites by the environmental agencies were eligible for Taiwan EPA subsidy. Since the tree growth is a long tern affair, the coordination of above two subsidy programs needs more discussion. After 20 years of afforestation, this study found that the income of wood harvested as sawn lumber is only 0.3 million NTD for the studied sites. If whole trees were sold for landscape plantation usages, the overall income would be 3.55 million NTD. However, the policies for more incentives for sales of landscape trees are required to increase the willingness of farmers’ participation. Three promotion meetings were held to present the principle of subsidy for ceased farming of polluted farmlands as soil control sites declared by Taiwan EPA, as well as the standard operation principles for pollution incidents of farmlands.

heavy metal pollution, phytoremediation, campor tree