Evaluation of stormwater microbiomes for the potential biodegradation of tire wear particle contaminants

Stormwater is a major source of many contaminants of emerging concern, which can be toxic to both aquatic and terrestrial organisms. This project aimed to identify novel biodegraders of toxic tire wear particle (TWP) contaminants associated with coho salmon mortality.This study has (i) characterized the prokaryotic communities of stormwater in both urban and rural settings; (ii) evaluated the ability of stormwater isolates to degrade two model TWP contaminants, hexa(methoxymethyl)melamine and 1,3-diphenylguanidine; and (iii) evaluated the toxicological impact of these model contaminants on the growth of six model bacteria. Rural stormwater possessed a diverse microbiome dominated by Oxalobacteraceae, Microbacteriaceae, Cellulomonadaceae, and Pseudomonadaceae taxa, while urban stormwater showed much less microbial diversity overall. Additionally, multiple stormwater isolates appeared capable of using model TWP contaminants as their sole carbon source. Each model contaminant was also found to alter growth patterns of model environmental bacteria including, with 1,3-DPG appearing more acutely toxic at high concentrations.This study identified several stormwater isolates that have the potential to be used as a sustainable solution to stormwater quality management.