Joint enhancement of lead accumulation in Brassica plants by EDTA and ammonium sulfate in sand culture

Article type: Research Article

Authors: Xiong, Zhi-ting | Lu, Ping

Affiliations: Department of Environmental Sciences,Wuhan University,Wuhan 430072,China

Abstract: When EDTA was added alone in the Pb-contaminated sand, the plant biomass and the total Pb amount in plant decreased in both species, Brassica pekinensis and B. juncea var. multiceps, though the shoot Pb amount increased. In contrast, when (NH_4)_2 SO_4 was added alone in the Pb-contaminated sand, little effect was observed on the shoot Pb amount, though the root Pb amount was significantly increased in B. juncea var. multiceps. When amending EDTA and (NH_4)_2SO_4 in combination, however, the shoot Pb amount in both species substantially increased, being, on an average, 2 times and 9 times higher than that in EDTA alone or (NH_4)_2 SO_4 alone amended treatment, respectively.The two amendments showed antagonism for plant growth, but synergism for Pb bioaccumulation. B. pekinensis showed its highest level of shoot and total Pb amount in the treatment amended with EDTA and (NH_4)_2 SO_4 only a half as much as in the other treatments. It is inferred that the mechanisms responsible for the joint-enhanced Pb accumulation might be concerned with the acidification of the growth medium, cation exchange reaction and relieving EDTA induced toxicity as results by amending ammonium sulfate.

Keywords: lead bioaccumulation, Brassica ammonium sulfate, ammonium sulfate, EDTA

Journal: Journal of Environmental Sciences, vol. 14, no. 2, pp. 216-220, 2002