Stormwater is a largely uncontrolled source of pollution in rural and urban environments across the United States. Concern regarding the growing diversity and abundance of pollutants in stormwater as well as their impacts on water quality has grown significantly over the past several decades. In addition to conventional contaminants like nutrients and heavy metals, stormwater is a well-documented source of many contaminants of emerging concern, which can be toxic to both aquatic and terrestrial organisms and remain a barrier to maintaining high quality water resources. Chemical pollutants like pharmaceuticals and personal care products, industrial pollutants such as per- and polyfluoroalkyl substances, and tire wear particles in stormwater are of great concern due to their toxic, genotoxic, mutagenic and carcinogenic properties. Emerging microbial contaminants such as pathogens and antibiotic resistance genes also represent significant threats to environmental water quality and human health. Knowledge regarding the transport, behavior, and the remediation capacity of these pollutants in runoff is key for addressing these pollutants in situ and minimizing ecosystem perturbations. To this end, this review paper will analyze current understanding of these contaminants in stormwater runoff in terms of their transport, behavior, and bioremediation potential.

Aim 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 contaminants associated with coho salmon mortality. Methods and Results 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 tire wear particle 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 tire wear particle 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. Conclusion This study identified several stormwater isolates that have the potential to be used as a sustainable solution to stormwater quality management.