Study on the Aging Effect and Bioavailability of Polycyclic Aromatic Hydrocarbons in Agricultural Soils Based on Different Extraction Forms
The different forms of polycyclic aromatic hydrocarbons(PAHs)in soil can provide a new perspective for under-standing the mechanism of aging effect and assessing bioavailability.The aging effect and bioavailability of PAHs in four dif-ferent types of agricultural soils in Wuhu City were investigated based on the different forms of PAHs defined by sequential extraction methods.The PAHs content in all four agricultural soils followed the order of slow-desorption form＞fast-desorp-tion form＞water soluble form.On the Oth day after exogenous PAHs entered the soil,the proportion of slow-desorption form reached 55.61％±21.59％.In the orchard soil with the lowest organic matter content,the proportion of slow-desorption form at 0 d was significantly lower than those in other soils,indicating that the PAHs of"fast adsorption and slow desorption"were closely related to organic matter.With the extension of the aging time of exogenous PAHs in soil,the slow-desorption form continued to increase to 75.57％±7.43％on the 90th day,while the water soluble and fast-desorption forms decreased from 11.20％±4.25％and 33.19％±20.24％to 0.89％±0.21％and 1.51％±1.11％,respectively.The non-extractable form calculated by mass balance reached 22.0％±6.8％,indicating that the aging effect of PAHs in soil is essentially a process of conversion from water-soluble and fast-desorption forms to slow-desorption form and even non-extractable form.The dynamics of this transformation process can be well simulated with a first-order exponential model.Among the different forms of PAHs,the water-soluble form was the most strongly correlated with the biota soil accumulation factor given by the model biological method(R=0.84,P＜0.01),indicating that water soluble PAHs could be used as a proxy index to evaluate the bioavailability of soil PAHs.
万方数据
维普
