鉛污染土壤特性探討及不同整治技術之研究

Lead Contaminated Soil Characterization and Remediation Technologies Assessment

林旻秀(Min-siou Lin)

指導教授 ： 程淑芬

朝陽科技大學/理工學院/環境工程與管理系/碩士(2012年)

摘要

鉛是土壤中常見的污染物，造成土壤中鉛污染的來源包括鉛蓄電池製造及冶煉、彈藥、金屬鑄造程序等，不同污染來源、不同鉛化合物所造成的土壤污染特性可能會有不同。本研究首先針對不同鉛污染來源土壤進行土壤特性與鉛鍵結型態相關性分析，其結果顯示可交換態與pH為負相關(r = -0.580，P < 0.01)；碳酸鹽態與有機質為負相關(r = -0.328，P < 0.01)；鐵錳氧化態(r = 0.450，P < 0.01)及殘留態(r = 0.637，P < 0.01)與CEC為正相關，影響鉛鍵結型態之因素為pH、CEC及有機質。
研究第二部分為對鉛污染土壤進行土壤清洗及植生復育兩種整治技術之研究。土壤清洗的部分使用HCl、HNO3、AlCl3、FeCl3、CaCl2、MgCl2及EDTA-4Na作為清洗劑，探討七種清洗劑對於土壤鉛含量及鍵結型態之去除效率。植生復育地點為一處受鉛污染場址，先對場址原生植物分析其鉛的吸收累積能力，選取鬼針草、野莧及向日葵作為場址植生復育之植物，探討其吸收累積土壤中鉛之能力。
土壤清洗的研究結果顯示，對於鉛鍵結型態主要以碳酸鹽態及鐵錳氧化態為主之土壤，HCl及HNO3能去除70%以上的鉛；鉛鍵結型態以可交換態為主之土壤，FeCl3、HCl及HNO3、EDTA-4Na及AlCl3能去除80%以上的鉛。對於去除各鍵結型態之能力，HCl及HNO3主要能去除碳酸鹽態及鐵錳氧化態達80%以上；AlCl3及FeCl3主要能去除碳酸鹽態66 ~ 96%；EDTA-4Na主要可去除可交換態及碳酸鹽態達70%以上、鐵錳氧化態58 ~ 96%。
植生復育的研究結果顯示，場址原生植物水丁香、鬼針草、牛筋草、苦蘵、龍葵、尖瓣花及野莧地上部對鉛之吸收含量可達100 mg kg-1以上。鬼針草地上部對鉛有最高的吸收量且能有效地將鉛從地下部轉移至地上部，植體也具有相當高的生質量，容易種植，具有做為植生復育植物的潛力。

關鍵字

向日葵 ； 鉛 ； 土壤清洗 ； HCl ； HNO3 ； AlCl3 ； 野莧 ； 鬼針草 ； 植生復育 ； EDTA-4Na ； FeCl3

並列摘要

Lead is the common pollutant in soil, which is mainly from the lead accumulator manufacturing, smelting, cartridge and metal casting procedures. Characteristics of soil polluted by different pollution sources and lead compounds may vary. This study conducted an analysis on the soil characteristics and lead bonding states of soil polluted by different pollution sources. The results showed that, the exchangeable was negatively correlated with pH (r = -0.580, P < 0.01), carbonate bound was negatively correlated with organic matter (r = -0.328, P < 0.01), and Fe-Mn oxides bound (r = 0.450, P < 0.01) and residual (r = 0.637, P < 0.01) were positively correlated with CEC. Factors affecting the lead speciation state included pH, CEC, and organic matter.

The second part of this study focused on two remediation technologies, which are soil washing and phytoremediation in lead-polluted soil. HCl, HNO3, AlCl3, FeCl3, CaCl2, MgCl2, and EDTA-4Na were used as the cleaning agent for soil washing to discuss on the removal effect of the 7 cleaning agent on the lead content and bonding states in soil. Phytoremediation site was a lead-polluted place. Absorption accumulation ability of native plant at site on lead was analyzed, and Bidens pilosa, Amaranthus viridis as well as Helianthus annuus were treated as the plant for phytoremediation to discuss their absorption accumulation ability of lead in soil.

The results of soil washing showed that, for the soil with lead under carbonate bound and Fe-Mn oxides bound, HCl and HNO3 were able to remove the lead for 70% or above. For the soil with lead under exchangeable, HCl and HNO3 were able to remove the lead for 80% or above. With regard to the ability to remove all the speciation, the removal ability of HCl and HNO3 on carbonate bound and Fe-Mn oxides bound was 80% or above; that of AlCl3 and FeCl3 on carbonate bound was 66~96%; that of EDTA-4Na on exchangeable and carbonate bound was 70% or above and on Fe-Mn oxides bound was 58~96%.

The results on phytoremediation showed that, the absorption volume of the aboveground part of native plant, such as Ludwigia octovalvis, Bidens pilosa, Eleusine indica, Physalis angulata L., Solanum nigrum L., Sphenoclea zeylanica Gaertn, Amaranthus viridis, at site on the lead was 100 mg kg-1 or above. The aboveground part of Bidens pilosa had the highest absorption volume on lead, and was able to transfer the lead from the underground part to the aboveground part. The plant had a high survival rate, which was easy to be planted and had the potential to be the plant for phytoremediation.

並列關鍵字

Phytoremediation ； Bidens pilosa ； Amaranthus viridis ； Helianthus annuus ； EDTA-4Na ； FeCl3 ； AlCl3 ； HNO3 ； HCl ； Soil Washing ； Lead

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