Topic Area: 6b. Microplastics and Nanoplastics in the Environment

Formatted Title:

Effects of Micro- and Nanoplastics on Degradation of Chlorinated Solvents and Energetics

Background/Objectives:

Bioremediation plays a major role in the transformation and detoxification of chlorinated solvents and only some strains of Dehalococcoides mccartyi (Dhc) can detoxify chlorinated ethenes to environmentally benign ethene. Pseudomonas fluorescens I-C and Gordonia sp. KTR9 strains have been reported for their capability with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation. Plastics, as synthetic chemicals, are extensively used in daily life and form smaller particles that accumulate in soils and sediments. The persistence of microplastics (MPs) and nanoplastics (NPs) in environmental systems has started to raise concerns. Inhibitory effects of nano/microplastics on biological processes like sludge digestion, nitrification/denitrification, hydrogen generation and methanogenesis have been recently documented, yet little is known on the impacts of MPs and NPs on bioremediation processes. Our study has focused on the potential inhibitory effects of Nylon 6 (NY6) and polystyrene (PS) of nano/microplastics on reductive dechlorination of chlorinated solvents and microbial degradation of RDX.

Approach/Activities:

The reductive dechlorination activity of mixed dechlorinating-culture SDC-9 and degradation of RDX by strain I-C and KTR9 in the presence of PS (10 µm and 10 nm) and nylon 6 (15-20 µm and 360 nm) microplastics and nanoplastics has been evaluated. The dechlorination of trichloroethene (TCE) has been monitored using gas chromatography with flame ionization detector (GC/FID). Dehalococcoides spp. cell abundance has been determined by quantitative PCR. Targeted proteomics was used to quantify process-specific trichloroethene reductive dehalogenase (TceA), vinyl chloride reductive dehalogenase (VcrA) and organohalide respiration involved molybdoenzyme (OmeA). For RDX experiments, RDX was determined using high pressure liquid chromatography (HPLC) and cell abundance was monitored via OD₆₀₀.

Yanchen Sun

Affiliation

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(Group 2, Poster Board #35) Effects of Micro- and Nanoplastics on Degradation of Chlorinated Solvents and Energetics