Benzo[a]pyrene degradation and bioaccumulation in soil-plant system under artificial contamination

Abstract

The involvement of benzo[a]pyrene (BaP) one of the most toxic polycyclic aromatic hydrocarbons (PAHs) in the soil-plant system causes its potential carcinogenicity and mutagenicity for human health. The aim of this article is benzo[a]pyrene (BaP) degradation and bioaccumulation in soil-plant system under artificial contamination in model experiment with Haplic Chernozem and that spiked with various doses of BaP (20, 200, 400 and 800μgkg−1) equivalent to 1, 10, 20 and 40 levels of maximal permissible concentrations (MPC) planted with spring barley (Hordeum sativum distichum). The experimental soil samples were planted every spring and incubated outdoor during 4years. The express-method of subcritical water extraction was used for BaP extraction from samples. It was established the values of BaP period of semi-degradation in soil (T50, y) contaminated with 10, 20 and 40MPC deviated from 1.4 to 1.8years, while these values in low contaminated soils deviated from 2.9 to 5.4years. It was found the BaP concentrations in plants depended on initial BaP contamination and reduced simultaneously with diminish of BaP concentration in the related spiked samples. Growing of spring barley in the BaP spiked soils lead to BaP accumulation in plants. The bioaccumulation factors for BaP in roots and vegetative part of barley plants (BAFr and BAFv respectively) fluctuated within 0.035–0.065 and 0.015–0.025 respectively at the 1st season and then reduced about twice to the 4th season. Meantime those values in control soils vice-versa increased twice from 0.03 and 0.01 respectively.