Cyanide is a high-volume production chemical and the most commonly used leaching reagant for gold and silver extraction. Its environmental behavior and fate is of significant concern because of its high toxicity. This paper presents an investigation of the feasibility of phytoremediation as an in- situ technique to treat cyanide-contaminated soil. Corn(Zea mays L.)and soybean(Glycine max(L.)Merr.)were used. Results from this tests indicated that low dose of cyanide(≤45.5 CN detectable effects under room temperature(23.0～26.0℃). Significant reduction in the plant growth rates(≥10%)was found at high cyanide concentration in the irrigation water(≥91.0 CN mg·L-1)used. The potential of detached leaves to remove cyanide was also investigated. Excised plant leaves(1.5 g fresh weight)were kept in a glass vessel with with 100 mL spiked aqueous solution(deionized oxygen-saturated water)at 23.5℃ for 28 h. The disappearance of cyanide from the aqueous solution was tracked photometrically. More than 90% cyanide in the aqueous solution was removed by plant materials over a 28-h exposure period. The cyanide removal capacity was determined to be 4.43 and 3.42 mg CN·kg fresh weight-1·hour-1 for soybean and corn, respectively. Resutls from this investigation indicated that plants and plant materials were all found to be able to efficiently remove cyanide from the contaminated medium through their internal enzyme systems. In conclusion, cyanide elimination with plants seems to be a feasible option for cleaning soils contaminated with cyanide or gold and silver mine waste and wastewater.
[1] 梁五生,毛碧增,李德葆.2001.烟叶片中氰丙氨酸合成酶活性的测定[J].植物生理学通讯,37(2):140～142.
[2] 中国国家环境保护总局<水和废水监测分析方法>编委会.1989.水和废水监测分析方法(第三版)[M].北京:中国环境科学出版社.306-313.
[3] Kort F,Spiteller M,and Coulston.2000.The cyanide leaching gold recovery porcess is a non-sustainable technology with unacceptable impacts on ecosystems and human:the disaster in Romania[J].Ecotox.Environ.Safet.46(4):241～245.
[4] Maruyama A,Saito K,and Ishizawa K.2001.β-cyanoalanine synthase and cysteine synthase from potato:molecular cloning,biochemical characterization,and spatial and hormonal regulation[J].Plant Molecular Biology,46(1):749～760.
[5] Miller J M,Conn E E.1980.Metabolisn of hydrogen cyanide by higher plants[J].Plant Physiology,65(2):1199～1202.
[6] Hendrickson HR and Conn EE.1969.Cyanide metabolism in higher plants.Puriification and properties of theβ-cyanoalanine synthase of blue lupine[J].Journal of Biological Chemistry,244(3):2632～2640.
[7] Manning K.1988.Detoxification of cyanide by plants and hormone action[A].In:Vennesland B(ed).Cyanide compounds in biology[C].Chichester:John Wiley & Sons,UK.92-110.
[8] Trapp S,Christiansen H,2003.Phytoremediation of cyanide-polluted soils.In:McCutcheon,S.C.;Schnoor,J.L.(Eds.).Phytoremediation:Transformation and Control of Contaminants[M].John Wiley and Sons,Hoboken,NJ,USA:829-862.
[9] Trapp S,Yu X Z,and Mosbaek H.2003.Persistence of MTBE against metabolism by Danish vegetation[.I].Environmental Science and Pollution Research.10(6):357～360.
[10] Mosher JB,Figueroa L.1996.Biological oxidization of cyanide:a viable treatment option for the minerals processing industry[J].Minerals Engineering,9(5):573～581.
[11] Press-Kristensen K.2002.Phytoremediation at SФrup Waste Site(In Danish)[D].Lyngby:Environment & Resources,Technical University of Denmark.1～72.
