| As one of the persistent organic pollutants with strong carcinogenic, teratogenic and mutagenic effect, benzo（a） pyrene（B[a]P） is gradually accumulating in soil and posing a serious threaten to soil environment quality. The B[a]P bioavailability and its impacts on soil respiration were investigated under simulated condition by using the superimposed method. Results indicated that contents of extractable and available B[a]P sharply declined in the first 28 d（0~28 d）, and then slowly decreased between 28 d and 56 d incubation time under both superimposed and one-time pollution method. Soil extractable and available B[a]P in superimposed pollution tests were 34.50%~57.29% and 19.00%~43.80% lower than that in the one-time pollution method, respectively. Soil respiration intensity decreased by 14.38% to 35.80% in the first 7 d incubation period, and then gradually recovered and kept stable between 11.51 mg·kg-1·h-1 and 15.69 mg·kg-1·h-1 at the end of the incubation time. In both superimposed and one-time pollution tests, the positive correlation relationship between soil available B[a]P and soil respiration intensity was testified in the whole incubation period. Results from this work provide a crucial data for evaluating ecological toxicity of soil B[a]P accumulative pollution. |
