City of Concord Complete Streets Study

The purpose of this report is to summarize the data collected as a part of the Concord Complete Streets Study and to provide the City with preliminary support in the progress to construct a safer, more bike and pedestrian friendly Concord. The developments and visions found in this document provide a platform for continued discussion on creating a more pedestrian and bicycle friendly environment that encourages other forms of transportation and provides alternatives to dependency on automobiles

City of San Luis Obispo, Open Space Survey

The City of San Luis Obispo (SLO) has eleven official public open spaces. Managing these places presents a challenge in providing top-tier environmental stewardship, while also accommodating passive recreational use and access, in an era of fiscal limitations and competing priorities. Given that reality and the changing population dynamics in the US, providing equal access to these facilities is of increasing importance, whether by car, bike, on foot or via public transit. These open spaces provide value (environmental, economic and social) primarily to residents, as well as visitors, and gaining a data-driven understanding of that value was a primary goal of this study. Within this framework, team of undergraduate and graduate students from CalPoly, San Luis Obispo worked under the direction of Dr. William Riggs and Natural Resources Manager Robert Hill, to evaluate the conditions, characteristics-of, and visitors-to SLO open spaces. To accomplish this, the project team conducted an initial facilities assessment of the existing conditions at the entrances to SLO’s open spaces. Following this, a survey was conducted to gather information about use, conditions and travel / access to local open spaces. This was complimented by use data gathered from electronic counters placed at open space entrances

San Luis Obispo Open Space Survey

The City of San Luis Obispo (SLO) has eleven official public open spaces. Managing these places presents a challenge in providing top-tier environmental stewardship, while also accommodating passive recreational use and access, in an era of fiscal limitations and competing priorities. Given that reality and the changing population dynamics in the US, providing equal access to these facilities is of increasing importance, whether by car, bike, on foot or via public transit. These open spaces provide value (environmental, economic and social) primarily to residents, as well as visitors, and gaining a data-driven understanding of that value was a primary goal of this study. Within this framework, team of undergraduate and graduate students from CalPoly, San Luis Obispo worked under the direction of Dr. William Riggs and Natural Resources Manager Robert Hill, to evaluate the conditions, characteristics-of, and visitors-to SLO open spaces. To accomplish this, the project team conducted an initial facilities assessment of the existing conditions at the entrances to SLO’s open spaces. Following this, a survey was conducted to gather information about use, conditions and travel / access to local open spaces. This was complimented by use data gathered from electronic counters placed at open space entrances

Methicillin-resistant Staphylococcus aureus in Southern California coastal waters: environmental exposure to humans and stormwater biofilters as a preventative solution

Antibiotic resistance is one of the greatest challenges to modern global health. Sources of antibiotic resistant bacteria (ARB) and antibiotic resistances genes (ARGs) to surface water include wastewater treatment plants, medical waste streams, and agricultural sites. Recent studies have identified stormwater as a source of ARGs, and often stormwater contains other contaminants such as heavy metals and antibiotics that select for antibiotic resistance. As an emerging contaminant, ARB and ARGs are not regulated or traditionally monitored in recreational swimming waters that may receive stormwater runoff. This research is divided into two parts: 1) Chapter 1 is an epidemiological study on surfers’ exposure to ARB in the ocean, and 2) Chapters 2 and 3 investigate the fate and transport of ARB, ARGs, and other pathogens and indicators in stormwater biofilters.Exposure to sources of ARB has been associated with colonization and infection in human populations, and recent work suggests the environment serves as an open reservoir available for transferring human pathogens. Surfers are a unique population for evaluating the relationship between environmental exposure and ARB colonization. Surfing involves a high frequency of unanticipated head submersions, exposures of long duration, and surfers are in the ocean year-round, particularly in the winter when storms occur, resulting in poor water quality due to urban stormwater contaminants. Beginning Fall 2018, two Santa Monica Bay surfing beaches were monitored for Methicillin-resistant Staphylococcus aureus (MRSA). Nasal swab samples were concurrently taken from a group of surfers and a non-surfing control group to investigate how this pathogen colonizes humans. Presumptive MRSA was always detected in marine samples, with highly elevated levels observed after stormwater runoff events. Surfers that surfed during wet-weather events were over six times more likely to be colonized by MRSA compared to controls, and also over three times more likely to be colonized than dry-weather surfers. This research suggests that the ocean may be an important reservoir of MRSA and have a special role in pathogen transmission to humans. Stormwater biofilters are a promising passive treatment solution for reducing microbial pollution in surface waters. While bioretention systems (biofilters) have been widely and effectively used to capture chemical pollutants from surface runoff, the effect of biofilters on both heavy metals and antibiotic resistance genes (ARGs) has been relatively understudied. The co-occurrence of heavy metals and ARGs is important because of known heavy metal co-selection in environmental compartments. Surface soil samples from six biofilters and bioswales in Southern California over three time periods were analyzed for ARGs, mobile genetic element (intI1), and 16S rRNA (proxy for total bacterial load). The impact of soil properties and the co-selective effect of nine heavy metals (both bioavailable fraction and total) on ARG levels in the biofilters were also investigated. Both relative sul1 and intI1 levels in biofilters were statistically greater than those detected in pristine soils. Total concentrations of arsenic, copper, lead, vanadium, and zinc exhibited significant correlations individually with relative abundances of sul1, sul2, tetW, and intI1. Soil organic matter, total nitrogen, total carbon, and the percentage of sand and silt within biofilters appeared to be significantly associated with absolute gene abundances of sul1, sul2, and tetW. Stronger relationships were found using a multiple linear regression model, suggesting multiple effects of soil properties, in addition to bioavailable and total heavy metals on the microorganisms within biofilters. While stormwater biofilters have been shown to remove chemical contaminants such as nutrients and heavy metals, their efficacy in removing microbial pathogens has been understudied. Full-scale biofilter studies are rare as most biofilter research has been conducted with laboratory-scale biofilters. Additionally, microbial removal is typically evaluated using traditional fecal indicator bacteria (FIB) as a proxy for pathogen removal, and it is not known if traditional indicators accurately reflect pathogen removal within biofilters. A pilot-scale biofilter located on the Glassell Public Works campus (Orange, CA) was synergistically studied for removal of conventional fecal indicators, bacterial and viral fecal source markers, antibiotic resistance genes, and bacterial and viral pathogens. Log reduction of fecal indicator bacteria (both genetic and culture-based) was high. Some of the pathogens tested were effectively removed, while the biofilter itself served as a reservoir for two pathogens (Campylobacter and Salmonella). The removal of HF183 did not match FIB or pathogen removal, with no removal observed. Viral fecal source markers PMMoV and crAssphage had satisfactory log reductions that were more comparable to those observed in both FIB and some pathogens. ARGs and intI1 showed gene-specific log reduction. These findings suggest that FIB and fecal source markers may not adequately represent pathogen removal in stormwater biofilters. This research will enhance our knowledge of the fate and transport of ARG and ARB in surface water and stormwater biofilter infrastructure. Additionally, it will serve to further our understanding of how the environment may transfer ARB to humans. The results of this research can illuminate appropriate public health responses and mitigation efforts for reducing antibiotic resistance in the environment

Nicotine Products Relative Risk Assessment: A Systematic Review and Meta-analysis

Background Nicotine products have been the subject of considerable innovation over the past few decades. While the health risks of combustible cigarettes and most tobacco-based products are well characterized, there is less clarity regarding newer nicotine products, and how they compare with the traditional forms. Methods In this study, we have developed a relative risk hierarchy (RRH) of 13 nicotine products based on systematic review of the scientific literature and analysis of the best available evidence. In total, 3980 publications were identified and screened, with 320 studies being carried through to the final analysis. The health risk data for each product was extracted and the level assessed. The products were analyzed in terms of their toxin emissions and epidemiological data, which were combined on an arbitrary scale from 0 to 100 (low to high risk) to derive a combined risk score for each nicotine product. Results Combustible tobacco products dominate the top of the RRH, with combined risk scores ranging from 40 to 100. The most frequently consumed products generally score highest. Dipping and chewing tobacco place considerably lower on the hierarchy than the combustible products with scores of 10 to 15, but significantly above heat-not-burn devices and snus, which score between 3 and 4. The lowest risk products have scores of less than 0.25 and include electronic cigarettes, non-tobacco pouches and nicotine replacement therapy. Conclusions The RRH provides a framework for the assessment of relative risk across all categories of nicotine products based on the best available evidence regarding their toxin emissions and the observed risk of disease development in product users. As nicotine products continue to evolve, and more data comes to light, the analyses can be updated to represent the best available scientific evidence

Limited Bacterial Removal in Full-Scale Stormwater Biofilters as Evidenced by Community Sequencing Analysis.

In urban areas, untreated stormwater runoff can pollute downstream surface waters. To intercept and treat runoff, low-impact or "green infrastructure" approaches such as using biofilters are adopted. Yet, actual biofilter pollutant removal is poorly understood; removal is often studied in laboratory columns, with variable removal of viable and culturable microbial cell numbers including pathogens. Here, to assess bacterial pollutant removal in full-scale planted biofilters, stormwater was applied, unspiked or spiked with untreated sewage, in simulated storm events under transient flow conditions, during which biofilter influents versus effluents were compared. Based on microbial biomass, sequences of bacterial community genes encoding 16S rRNA, and gene copies of the human fecal marker HF183 and of the Enterococcus spp. marker Entero1A, removal of bacterial pollutants in biofilters was limited. Dominant bacterial taxa were similar for influent versus effluent aqueous samples within each inflow treatment of either spiked or unspiked stormwater. Bacterial pollutants in soil were gradually washed out, albeit incompletely, during simulated storm flushing events. In post-storm biofilter soil cores, retained influent bacteria were concentrated in the top layers (0-10 cm), indicating that the removal of bacterial pollutants was spatially limited to surface soils. To the extent that plant-associated processes are responsible for this spatial pattern, treatment performance might be enhanced by biofilter designs that maximize influent contact with the rhizosphere