铅和苯并[a]芘混合污染酸性土壤上黑麦草生长及对污染物的吸取作用

GROWTH AND POLLUTANT UPTAKE OF RYEGRASS PLANTS GROWN IN A Pb-B[a] P MIXED POLLUTED ACIDIC SOIL

设置铅(Pb)处理浓度为0、5001、0002、000 mg kg-1(烘干土计),苯并[a]芘(B[a]P)处理浓度为0、12.5、255、0 mg kg-1(烘干土计),完全组合设计,对每一处理通过种植和不种植黑麦草盆栽试验,研究了B[a]P和Pb混合污染酸性红砂土上黑麦草(Lolium perenneL.)的生长及对污染物积累的吸取作用。试验表明,铅是抑制黑麦草株高和产量的主要因素,在低Pb处理浓度下,B[a]P对黑麦草生长有一定的促进作用。在试验61 d内,黑麦草吸收的铅占土壤铅添加量的4.7%,黑麦草吸收的B[a]P占土壤B[a]P添加量的0.023%;种植黑麦草的土壤B[a]P残留率平均为42.6%;而未种植黑麦草的土壤B[a]P平均残留率为50.9%。该研究结果表明,当Pb-B[a]P混合污染土壤时,在一定的浓度范围内黑麦草能吸收土壤中的Pb和B[a]P,黑麦草对Pb-B[a]P混合污染土壤有一定的吸取修复作用。

Plant growth and pollutants uptake by ryegrass （Lolium perenne L. ） grown in a Pb and B[ a] P polluted acidic soil developed from red sandstone was studied in a pot experiment. Soil samples treated with Pb at the rates of 0, 500, 1 000 and 2 000 mg kg^-1 （on a basis of oven dried soil） and B[ a] P at 0, 12.5, 25 and 50 mg kg^-1 were planted with or without ryegrass. The plants were harvested 61 days＇ after its growth. The contents of Pb and B[a]P in the soil and in the plant shoots and roots as well as plant height and dry mass of ryegrass were determined. Results show ryegrass biomass decreased substantially due to Pb toxicity. In the planted soil 4.7 % of the Pb applied and 0.023 % of the B[a] P applied was taken up by ryegrass, and about 42.6% of the B[a]P applied was left as residue, whereas in unplanted control soil, 50.9% was. The findings suggest that cultivation of ryegrass may help remedy Pb-B[a]P mixed polluted acidic sandy soil.