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pathogens still pose varying risks to humans, including cow and canine waste and, to a lesser extent, bird waste. Water quality standards were set based on the conservative principle that the indicator bacteria represent the worst-case scenario chance of infection. The protective manner in which these water quality standards were set means that in cases where impairment sources other than human are dominant, the same concentration of bacteria represents a different risk level. Recent research has also shown that many of these indicator bacteria can survive and reproduce in the environment and thus are not representative of new fecal pollution and pathogens inputs. Guidance from the EPA (2014) reflects this fact and allows a movement to bacteria standards that reflect rates of illness specific to a particular location. Quantitative microbial risk assessment (QMRA) is the developing process that builds upon the understanding of site-specific source profiles determined in the MST process. QMRA can involve a number of steps, ranging from very precise sampling for determining pathogen concentrations to site-specific epidemiological studies. Data produced in this process are used to calculate a site-specific profile that determines an associated public health risk for different levels of bacterial concentrations. Based on this profile, a bacterial water quality standard can be set for that location that represents an acceptable illness rate and risk level. New Bacterial Treatment Options While treatment of bacterial point sources is fairly well understood, nonpoint source bacteria present a more complicated problem. Source controls should always be the first and most effective choice, but they are not always sufficient to meet targets. Therefore, additional measures are often required. Low-impact development (LID) and green infrastructure that emphasizes infiltration are preferred best management practices (BMP). These LID BMPs focus on the removal of flows carrying bacterial pollution and thus represent a powerful tool for remediation of bacterial pollution and offer the added benefits of hydromodification and groundwater replenishment. However, infiltration is not always feasible due to underling soils or volume requirement. As such, other types of structural treatments have been developed and utilized with varying levels of success. Early treatment attempted to mitigate in-stream bacteria by adding ozone and chlorine directly to impaired waters to kill the bacteria; however, these methods were often ineffective and often introduced additional problems to the watershed. More recently there have been a number of commercially available products that claim to treat bacteria, particularly in stormwater during the collection phase. Many of these interface directly with the catch basin structure. Examples include fabrics treated with antimicrobial elements that attach to floatable excluders and bioinfiltration media designed to kill bacteria by physically breaking down cell membranes. GIS Innovation And Mobile Accessibility The advancements in understanding the host sources, relative risks, and geographical hot spots have produced a wealth of knowledge for use in the decision-making process for dealing with bacterial pollution. That said, this data can be overwhelming if not organized in an easily digestible and relatable manner. Thankfully, the water and planning industries are in the midst of an information technology and mobile revolution. Today we are blessed with a number of desktop and mobile tools that focus on improving water quality and allow decision makers, policymakers, engineers, planners, and the general public to collaborate in an effort to achieve the shared goal of improving water quality in an impaired local watershed. Central to this technological revolution are geospatial planning tools that build on GIS. Many different data layers are able to be observed simultaneously in the office and in the field on mobile devices to understand the interplay of sources with their surroundings. These new mobile-enabled GIS systems are designed to capture, store, manipulate, analyze, manage, and present a host of spatial and geographical data in real time. The available tools extend beyond accessibility to the technical elements, offering a look at the feasibility and costs of a watershed retrofit to help make informed decisions, apply for grants, and jumpstart long-term ideas based on current and future watershed concerns. iWATR (www.iwatr.com), for example, allows users to deeply understand their surrounding waterways by identifying potential sites for BMP, suggest BMP options for local impairment, estimate treatment volumes, and ultimately project costs for construction and lifetime maintenance and usage. Summary While bacterial contamination presents an important challenge to protecting the beneficial usages of our nation's waters, there is an ever-growing toolkit of cutting-edge applications to meet them. If the past decade's trend is any indication, technologies on the horizon will continue to revolutionize how we look at this problem. As technology advances and our reliance on mobile tools continues to increase, the GIS data available to all stakeholders will keep pace to help incite a more-educated population that understands the issues and works together to ensure we live in a world with clean and safe waterways. n 14 wateronline.com n Water Innovations MICROBIALCONTAMINATION Map of 303(d) Pathogens Impairment in California (2010). Dr. J. Michael Trapp is a Project Manager for Michael Baker International in Southern California, focusing on water and sediment quality. He earned his Ph.D. from the University of Miami in marine and atmospheric chemistry and has experience conducting research on the fate and transport of aerosols, nutrients, metals, and bacterial contaminants. About The Author