Remedying PAHs contaminated farmland soil by zucchini with earthworm and fermented cow dung application

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants in the soil. Efficient remediation of PAHs in the soil has been a hot research. In this study, inoculated earthworms and fermented cow dung were used to phytoremedy soil contaminated by PAHs in order to improve the efficiency of bioremediation. A pot culture experiment was carried out to study the influence of fermented cow dung(FCW) and earthworm on remedying soil contaminated by polycyclic aromatic hydrocarbons (PAHs) using zucchini（Cucurbita moschata. Four treatments containing ①adding FCW; ②earthworms inoculation; ③earthworms inoculation and adding FCW; ④non-inoculum and adding FCW( CK); ⑤non-inoculum, adding FCW and planting(NO), were applied to PAHs contaminating soil. The plants were harvested after 10 weeks of growth. The joint action of earthworm inoculation and adding FCW promoted plant biomass and was good for plant surviving in soil contaminated by PAHs. The treatment of earthworm inoculation only and FCW added improved the efficiency that PAHs (3-5 rings) were absorbed into the plant, and the lowest PAHs content in shoots was 6 times of that in roots. Compared to the role of the soil itself, the removal efficiency of PAHs compounds above 3 ring increased more than 23% by interaction of earthworms inoculation, FCW and zucchini. Therefore, with earthworms and FCW, the zucchini played a potential role in phytoremediation of PAHs contaminating soil.