Increases in outdoor recreation in Olympic National Park contribute to increases in human fecal matter deposition in sensitive marine ecosystems, including areas in which the Quileute Tribe has Treaty rights to conduct subsistence fishing (e.g., for shellfish) and cultural practices. Human fecal matter containing pathogens enters sand, soil, and marine waters, and benthic species (e.g., shellfish), presenting human health risks to Tribal communities and outdoor recreationists. In this study, we collected 84 marine water samples and 116 sand and soil samples from two beaches in Olympic National Park during the summer of 2021. Total coliforms and Escherichia coli were quantified, and E. coli isolates phenotypes and genotypes were characterized. Of the 200 E. coli isolates, 80% carried a human-associated genetic marker (H8 and/or H12), 72% harbored sul1, an antibiotic resistance gene associated with anthropogenic sources, and 17% tested positive for bla_CTX-M, a beta-lactamase resistance gene of clinical relevance. Using Vitek 2 testing of antibiotic resistance phenotypes, resistance to ampicillin was the most common amongst the collected E. coli isolates, followed by resistance to tetracycline and trimethoprim-sulfamethoxazole. Moreover, results highlight the magnitude and extent (spatial distribution) of human-associated fecal contamination in the study area during the height of the tourist season. Our findings can inform land managers of the ways in which increases in human fecal matter on marine beaches can pose human health risks in different parts of ecosystems (e.g., forests, sands, and marine waters).

Urban streams are frequently impacted by fecal contamination with stormwater runoff being an important contributor. Streams of Washington District of Columbia (USA) are no exception, as they often display chronic levels of bacterial pollution and are receiving waters for municipal stormwater outfalls. In the District, polluted urban streams drain into larger water systems designated for primary contact recreation, making stream management vital to ensure safe swimming conditions. Recreational water quality is typically monitored with general fecal indicator bacteria (FIB), such as E. coli, which provides information on the estimated total level of fecal pollution and potential public health risks. However, FIB do not provide information on sources of fecal waste, making water quality management more challenging. Quantitative fecal source identification methodologies can complement FIB monitoring, characterizing key fecal pollution source trends and evaluating public health risk in parallel. This study assesses paired measurements of host-associated genetic markers, E. coli, and precipitation from seven low-order urban streams of the Anacostia Watershed over a 13-month period. Each stream is impacted by multiple municipal stormwater outfalls and stream catchments represent a gradient of land use. Five host-associated genetic markers designed to characterize human (HF183/BacR287 and HumM2), dog (DG3), avian (GFD), and ruminant (Rum2Bac) fecal sources were quantified to describe fecal pollution trends. Findings indicate that human, pet, and wildlife waste all impact water quality in the District of Columbia and demonstrates that combining fecal source identification with routine E. coli monitoring improves urban water quality management.

The ongoing climate crisis is likely to drive large biogeographic shifts through an increased occurrence and severity of wildfires. Concurrently, the wildland-urban interface (WUI), the area where houses meet wildland vegetation, is the fastest-growing land use type in the United States. Although the last several years have seen numerous high-profile WUI fires, there is little known about the unique characteristics of WUI fires and the resulting chemical and ecological transformations induced in affected environments. To better characterize the transport of WUI-fire toxicants in aquatic systems, we must better understand how they interact with microbiological communities. This presentation will detail a novel reactor design developed to investigate the effects of WUI-fire ash on the structure of a field-extracted stream microbial community. The 16S rDNA sequencing results indicate that post-fire urban runoff significantly restructures the microbial community. This ecological shift was further characterized by chemical analyses to support the toxicological understanding of WUI runoff. Combined, these results indicate the water quality hazard WUI runoff poses to aquatic microbial communities after fires.

Urbanization has significant impact on water resources, evidenced by the large number of urban streams classified as being impaired on the 303(d) list. Tremendous efforts have been made to improving these impaired streams, requiring the development of effective and efficient techniques for the evaluation of stream impairment and response to mitigation efforts. In this study, the stream microbiome was investigated as potential biomarkers for the impact of urbanization on stream impairment. Stream water samples were collected from reference streams with minimal impact from urbanization as well as streams impacted by urbanization to various extent in East Tennessee. The stream microbiomes were characterized by high-throughput sequencing. In addition, E. coli was also enumerated as an indicator for microbiological impairment following standard methods. The presence of E. coli was found to average 31 CFU/100-mL in reference streams and 1,260 CFU/100-mL in urban streams, indicative of the significant impact of urbanization on stream water quality. Microbiome analysis showed that the most abundant constituents of the stream microbiome was represented by Burkholderiaceae and Flavobacterium in both reference and urban streams. However, microbial populations abundant in reference streams, particularly Sediminibacterium and Rhodoluna, exhibited significantly reduced relative abundance in the urban streams, decreasing from 2.2% to 1.3% and from 2.2% down to 1.1%, respectively. In contrast, Pseudomonas, Hydrogenophaga, and Massilia were three major microbial populations showing significant increases in abundance in urban streams in comparison with reference streams. Findings from this study provide important insight into potential biomarkers specifically associated with the impact of urbanization.

Wildfires, floods and other disasters can profoundly impact infrastructure for large and small water systems, and plumbing safety. Tens of thousands of public water systems and more than 50% of buildings nationwide are vulnerable to wildfires alone. Local, county, and state health officials are often the first organizations utilities and property owners approach after a disaster when drinking water safety is a concern. Lessons from responding to and helping communities recover from chemical spill, backflow incidents, wildfires and other disasters since 2014 will be described. These will include wildfires in California, Colorado, Oregon, and New Mexico as well as chemical spills. Field experiences will be described pertaining to helping health departments and local governments identify chemical health risks, decontaminate infrastructure, and provide advice to infrastructure owners. Pilot- and bench-scale study results conducted in direct response to health official and disaster survivor requests will be shared. These studies have identified chemical contamination sources, contamination and decontamination of metal and plastic pipes, water softeners, water tanks, among other materials. Information provided can be relied upon to make public health decisions and will also outline current knowledge-gaps health officials may encounter. Some current gaps include the conditions that should prompt different water use orders, testing and decontamination protocols, contaminant fate and transport, and communication practices. Results of studies examining population needs specific to water system contamination. will also be shared. Efforts were funded by the U.S. National Science Foundation, U.S. Environmental Protection Agency, American Water Works Association, Water Research Foundation, and community foundations.