Citric acid-assisted phytoextraction of lead: A field experiment

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• 作者：Eriberto Vagner Freitas^a ; Clí ; stenes Williams Nascimento^b ; ^{clistenes@depa.ufrpe.br} ; Adailson Souza^a ; ^b ; Fernando Bruno Silva^a ; ^b
• 关键词：Phytoremediation ; Organic chelants ; Heavy metal ; Soil contamination
• 刊名：Chemosphere
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：92
• 期：2
• 页码：213-217
• 全文大小：892 K

文摘

Soil contamination with heavy metals has become a serious environmental problem that requires affordable strategies of remediation. This study was carried out to assess the performance of maize and vetiver in the phytoextraction of Pb from a soil contaminated by battery recycling activities. The species were planted with different spacings between rows (0.80, 0.65 and 0.50 m). Citric acid (40 mmol kg^?1) was applied on each experimental plot on the 61st d of cultivation in order to solubilize the Pb and assist the phytoextraction. The results showed that the chelating agent promoted a 14-fold increase in the Pb concentration in maize shoots as compared to the control, which accumulated only 111 mg kg^?1 of the metal. The citric acid induced a Pb concentration in vetiver shoots that was 7.2-6.7-fold higher than the control at both the 0.65 and 0.50 m plant spacing, respectively. The use of citric acid increased substantially the uptake and translocation of Pb to the shoots, regardless of plant spacing. Citric acid was efficient in solubilizing Pb from the soil and inducing its uptake by both species. Environmentally-friendly and cost effective, commercial citric acid is recommended for assisting Pb-phytoextraction in the studied area. Due to the low natural solubility of Pb and a time frame needed of longer than 150 yr to accomplish the clean-up, phytoextraction with no chelate assistance is not recommended for the area.