Microbiome resistance mediates stimulation of reduced graphene oxide to simultaneous abatement of 2,2',4,4',5-pentabromodiphenyl ether and 3,4-dichloroaniline in paddy soils.

Paddy soils near electrical and electronic waste recycling sites generally suffer from co-pollution of polybrominated diphenyl ethers and 3,4-dichloroaniline (3,4-DCA). This study tested the feasibility of reduced graphene oxide (rGO) to stimulate the simultaneous abatement of 2,2',4,4',5-pentabromodiphenyl ether (BDE99) and 3,4-DCA in percogenic paddy soil (PPS) and hydromorphic paddy soil (HPS). rGO improved the debromination extent of BDE99 and the transformation rate of 3,4-DCA in PPS, but did not affect their abatement in HPS. The inhibition of specific fermenters, acetogens, and methanogens after rGO addition contributed to BDE99 debromination by obligate organohalide-respiring bacteria (OHRB) in PPS, but relevant soil microbiomes (e.g., fermenters, acetogens, methanogens, and obligate OHRB) responded little to rGO in HPS. For 3,4-DCA, the enhanced activities of nitrogen-metabolic chloroaniline degraders by rGO increased its transformation rate in PPS, but was compensated by the decreased biotransformation from 3,4-DCA to 3,4-dichloroacetanilide after the addition of rGO to HPS. The discrepant stimulation of rGO between PPS and HPS was mediated by soil microbiome resistance. rGO has the application potential to stimulate the simultaneous abatement of polybrominated diphenyl ethers and chloroanilines in paddy soils with relatively low microbiome resistance.