Effects of fermented cow dung and dry powdered sludge from papermaking waste on mycorrhizoremediation of PAH-contaminated soils
发酵牛粪和造纸干粉对多环芳烃污染土壤菌根修复的影响

A greenhouse pot-experiment was carried out to investigate effects of fermented cow dung (FD) and dry powdered sludge of papermaking waste (PP) on phytoremediation of PAHs-contaminated farmland soils by arbuscular mycorrhizal fungi (AMF) infected alfalfa (Medicago sativa L.). The addition of 0.5% to 2.0% FD had no significant effect on AMF infection rate, but could promote growth of alfalfa (P<0.05). PAHs residues in the 1.0% and 2.0% FD treatments were lower than the control treatment. The addition of 0.05% and 0.1% PP enhanced AMF infection rate significantly, and plant biomass as well (P<0.05), while the addition of 0.2% PP had negative effect on them (P<0.05). Only 0.05% PP addition significantly decreased PAHs residues (P<0.05), and degradation rates of PAHs with three, four or five-ring were higher than those of the control (P<0.05), respectively. A significant linear regression relationship was observed between PAHs degradation rate in soil and the AMF infection rate in plant roots (P<0.05). These results indicated that proper quantities of FD could increase nutrition to promote plant growth, but had little effect on the degradation of PAHs. However, micro amounts of PP accelerated AMF infection to improve plant growth and the degradation of PAHs, suggested that it could be used as an irritant material in mycorrhizoremediation of PAHs-contaminated soils.