污泥施肥铅对作物污染的研究

Crops Lead Pollution by Sludge Land Application.

采用盆栽和小区试验,研究在石灰性土壤上污泥施肥时铅污染对水稻和大豆生长发育的影响,两种作物对土壤中铅的吸收、迁移和累积规律。结果表明,铅投加量为2000mg/kg时,水稻和大豆的产量降至低于对照90％以下;铅投加量为3000mg/kg时,大豆籽粒铅含量仍未超过1mg/kg;但土壤中铅含量为260mg/kg时,水稻盆栽糙米中的铅含量达到1mg/kg。根据试验结果建议将污泥农田施用时铅的控制标准修订为600mg/kg。

Pot experiments and field trails were conducted to study the effect of soil lead levels on phytotoxicity, growth and tissue accumulation in soybean and rice grown on sludge treated calcareous soil. The results indicated that lead didn' t cause significant growth depression symptoms of the two crops. The lead tolerabilities of two crops were equal. As a whole , the higher lead concentration in soil would bring about higher lead concentration in crops tissue. The lead accumulation rate of the two crops was different, soybean absorbed fewer lead than rice. Soil lead concentration 260mg/kg would make rice seed lead concentration to reach 1mg/kg. This value was suggested as critical level in the soil, and 600mg/kg was calculated as maximum permissible concentration in sludge when it is applied on cropland.