Effects of black carbon and earthworms on the degradation and residual distribution of 14C-2,4-dichlorophenol and 14C-phenanthrene in soil

Abstract

lack carbon (BC) and earthworms have the potential to alter the behavior of a wide range of chemicals in soil. However, little is known about the combined effects of BC and earthworms on the fate of these chemicals in soil. The degradation and residues distribution of 14C-2,4-dichlorophenol (14C-2,4-DCP) and 14C-phenanthrene in a soil amended with different levels of BC (0, 0.1, 1, and 5%) or/and the earthworm Metaphire guillelmi over 30 days were investigated. BC and earthworms inhibited the mineralization of 14C-2,4-DCP and 14C-phenanthrene, except that the mineralization of 14C-phenanthrene in the soil with 0.1% BC was promoted. When earthworms and BC were amended in the soil together, the inhibitory effects of mineralization were much higher. Earthworms markedly reduced the amounts of 14C-2,4-DCP residues in the soil humin fraction in the presence of BC and significantly lowered the amounts of 14C-phenanthrene residues in humin only in soil with 5% BC, indicating that earthworms had the ability to affect the fate of chemicals with different hydrophobicity in soil amended with BC.