EPA-104-GA03-03-A080

104

23,800 千元

提升土壤及地下水污染調查及整治技術工作

2015/05/20

2017/01/19

賴允傑

土污基管會

詹萬芳

瑞昶科技股份有限公司

土壤及地下水

重金屬污染農地、污染土壤改善技術、農藝管理技術

heavy metals contaminated rural soil, remediation techniques of contaminated soil, agricultural management

程淑芬；蔡呈奇；賴鴻裕

許正一

黃泰祥

02-77060566#145

mitch@apollotech.com.tw

本計畫透過系統性書件資料之蒐集彙整，參酌歷年土基會委員會會議資料，專業人士諮詢成果及農民訪談意見，歸納可加強重金屬污染農地現行行政管理及污染改善作業之關鍵議題。同時針對作物高鎘污染風險農地成因辦理調查作業，瞭解影響作物吸收鎘之原因包含土壤環境特性、灌溉水水質、水稻品種及農民田間耕作管理方式等因素，而食用作物鎘濃度易超過重金屬限量標準之可能因子，研判主要應受土壤水分管理因素影響所致，與土壤排水性質、配水供給及田區灌溉管理方式有關，建議採農藝管理措施及限制耕種特定作物避免作物鎘污染情事。 經蒐集國內外重金屬污染農地管理相關法令、管理對策及污染改善技術，「移除土壤污染物」及「穩定化土壤污染物降低危害風險」為兩種國內外主要之污染改善策略。本計畫篩選具國內發展潛力之農藝管理技術辦理田間試驗，評估對於重金屬污染農地之改善效益。試驗結果顯示，(1) 施用石灰物質（苦土石灰及蚵殼粉）顯著提升土壤酸鹼值，具有降低重金屬污染農地土壤生物有效性指標銅、鋅及鎳濃度之功能，為具潛力之農藝管理技術；施用有機資材時宜使用完全腐熟之材料，確保其穩定土壤重金屬之功能。(2) 植體重金屬濃度與重金屬傳輸機制有關，食用部位重金屬濃度具有一累積上限值，並未隨土壤重金屬濃度提高。糙米銅濃度多低於10 mg/kg、鋅濃度多低於30 mg/kg、鎳濃度多低於15 mg/kg、鉻濃度低於1 mg/kg，與國內歷年試驗結果相符，且糙米中重金屬濃度尚符合食用衛生安全。本試驗研究顯示受銅、鋅、鉻、鎳污染之農地土壤並不致影響糙米之食用安全。(3) 土壤中銅濃度低於700 mg/kg之受污染農地並不致造成水稻毒害或影響稻作產量。 生物炭現地穩定土壤污染物及植生萃取技術為兩項國內外矚目之新興污染改善方案，本計畫以盆栽試驗評估其污染改善應用潛力。試驗以兩種市售生物炭商品為材料，藉土壤生物有效性指標重金屬濃度及種植水稻評估，結果顯示生物炭穩定重金屬效益並未顯著，推測可能與生物炭製備過程中熱裂解反應不完全有關，以致無法有效吸附土壤重金屬污染物。本計畫透過菌根菌及植生萃取技術之搭配，試驗新穎技術之污染改善效益，取非洲鳳仙花、向日葵、新幾內亞非洲鳳仙花及玉米等植株，於根部接種菌根菌，栽培後評估植生整治效益。菌根菌可有效促進植生生長狀態，然而，植株每年每公頃對銅、鋅、鉻及鎳之移除量分別介於0.2～4.5 g、2.0～37 g、低於0.15 g及1.3～8.8 g，考量長期列管之行政成本及農民損益，並不建議採植生整治技術作為銅、鋅、鉻、鎳污染農地之單一改善作業方式。建議朝向篩選可高密度種植且機械採收之本土農藝作物，以提高土壤重金屬移除效率。 綜合各項工作內容及成果，通盤分析現行國內重金屬污染農地污染改善辦理方式及問題，並參考國內外之管理策略及污染改善技術，建議將受污染農地管理作業自污染整治提升至資源管理之層級，應考量土壤資源有效利用性及污染物毒性特性後，針對毒性較低之銅鋅鉻鎳污染農地場址，經充分風險溝通後宜朝向綠色整治方式改善。考量行政管理實務後，本計畫研提符合國情之「重金屬污染農地改善及管理對策整體規劃」，作為計畫主辦單位整體農地管理政策及污染改善技術之參考。

重金屬污染農地、污染土壤改善技術、農藝管理技術

EPA-104-GA03-03-A080(本文).pdf

22MB

2017/4/1 上午 12:00:00

This project identifies the crucial issues of the administration and remediation for the farm land contaminated with heavy metals, and aims at proposing the applicable amendment to the current administrative measures. With comprehensive information collected, including (1) committee meeting minutes of the Soil and Groundwater Pollution Remediation Fund Management Board, (2) the consultation results with the professionals, and (3) the suggestions from the farmers, therefore, this project evaluates several critical issues around the administrative measures and remediation technologies. Since the fact that cadmium pose severe risk on crop hygiene and affected by several factors including soil characteristic, the quality of irrigation water, the variety of rice cultivar, and agricultural water management. Accordingly, the project implements the investigation to clarify dominant factor and selects representative farmland targets. After systematic investigation and results evaluation, aerobic soil water regime might be attributed to elevation of the cadmium concentration in the rice tissue, which might be affected by drainage quality of the site, availability of irrigation water and the manner of agricultural water management. Hence the project proposed two measures to mitigate the crop contamination by cadmium, including (1) conduct agricultural management and (2) permit specific crop cultivation. By collecting and reviewing both domestic and abroad ordinances and management strategies of farmland remediation, two popular strategies served as main trends are listed as follow, (1) remove the contamination from soil, and (2) in-situ stabilization of heavy metal in the soil to reduce the hazardous risk. Considering the availability of technology for domestic use, the project proposes the promising agricultural management technologies. Afterwards, the field experiment is conducted on the Cu, Zn, Cr and Ni contaminated site to evaluate the performance of the strategies. The results are listed as following: 1. Soil pH was significantly raised after lime and oyster shell application, and the availability of copper, zinc, and nickel was reduced remarkably. Thus, adopting alkaline material such as lime is identified as a potential agricultural management to mitigate contamination. Benefit of heavy metals stabilization in soil might be achieved when green manure was mutually composted. 2. The contaminants concentration in the rice tissue is related to the translocation mechanism of paddy rice. Upper limit of heavy metal concentration in the rice tissue is observed, and which won’t be elevated with soil concentration. Most contaminants concentrated in the rice root, while the concentration of heavy metal in the brown rice was found as follow, Cu concentration was lower than 10 mg/kg, Zn concentration was lower than 30 mg/kg, Ni concentration was lower than 15 mg/kg, and Cr concentration was lower than 1 mg/kg, which was similar to historical records. Therefore, the project recognizes the safety of the rice and is not affected by soil contaminant. 3. No toxic appearance on the rice plant was observed during the growing period in the experiment. Furthermore, the rice yield and quality was also not affected by the soil contaminants, when the Cu concentration in the soil was not higher than 700 mg/kg. Around the world, applied biochar to stabilize heavy metals in soil and phytoextraction extraction are two promising technologies among contaminated soil remediation. The project evaluates the remediation potential by conducting pot experiments. 1. Two commercial biochars are tested, while Availability of heavy metals in the soil and the metal concentration in the crop tissues are two main factors to evaluate the experiment result. Results show that the benefit of biochr amendment is not prominent, since the material are unable to adsorb the heavy metals thus decrease the available concentration in soil and plant tissue. Reason inferred might be related to poor affinity between the heavy metals and the functional groups, which attributed to the impropriate pyrolysis process of the biochar. 2. Four plant species are inoculated with arbuscular mycorrhizal fungi (AMF) to evaluate the effect of phytoextraction. Including Helianthus annuus, Zea mays and two species of Impatiens walleriana are tested. The biomass of the plant is significantly increased by AMF inoculation, while the uptake amount of Cu, Zn, Cr and Ni annul per ha are 0.2-4.5 g, 2.0-37 g, lower than 0.15 g, and 1.3-8.8 g, respectively. Considering the long-term administrative control and the interest loss of farmers, phytoremediation cannot serves as a single approach to reduce soil metal concentration and meet the regulation standard. To strengthen the remediation effect, domestic agronomic crops with developed cropping system will be a promising candidate. Soil is more than the natural resource, but the precious properties of every human generation. The project emphasized the necessity to regard the contaminated soil as a resource. Differentiate the soil contaminants by their toxic characteristic and consider correspondent remediate measurements. For the site contaminated with Cu, Zn, Cr and Ni, green and sustainable remediation methods are advised and should follow with comprehensive risk assessment. The project considers the agricultural environment as a whole, introduces the “Blueprint of Remediation and Management Strategies for Farmland Contaminated with Heavy Metals” as the reference for the authority to develop the policies and technologies for the farmland contaminated with heavy metals, after analyzing the obstacles in current administrative management, reviewing the management strategies and remediation technologies both domestic and abroad, as well as considering the operation mechanism of the Soil and Groundwater Pollution Remediation Fund Management Board.

heavy metals contaminated rural soil, remediation techniques of contaminated soil, agricultural management