Tracking the downstream impacts of inadequate sanitation in central Appalachia

A 22-Site Comparison of Land-Use Practices, E-coli and Enterococci Concentrations

Land-use practices can greatly impact water quality. Escherichia (E.) coli and Enterococcus are accepted water quality indicators. However, surprisingly little research has been conducted comparing both organisms' population density relationships to land use practices and water quality. Stream water grab samples were collected monthly (n = 9 months) from 22 stream monitoring sites draining varying land use practice types in a representative mixed-land-use watershed of the northeastern United States. E. coli and enterococci colony forming units (CFU per 100 mL) were estimated (n = 396) and statistically analyzed relative to land use practices, hydroclimate, and pH, using a suite of methods, including correlation analysis, Principal Components Analysis (PCA), and Canonical Correspondence Analysis (CCA). Correlation analyses indicated significant (p < 0.05) relationships between fecal indicator bacteria concentrations, water quality metrics and land use practices but emphasized significant (p < 0.05) negative correlations between pH and instream enterococci concentrations. PCA and CCA results indicated consistent spatial differences between fecal indicator bacteria concentrations, pH, and land use/land cover characteristics. The study showed that pH could be considered an integrated proxy variable for past (legacy) and present land use practice influences. Results also bring to question the comparability of E-coli and enterococci relative to dominant land use practices and variations in pH and provide useful information that will help guide land use practice and water pollutant mitigation decision making.

Pollutant co-attenuation via in-stream interactions between mine drainage and municipal wastewater

Municipal wastewater (MWW) and mine drainage (MD) are common co-occurring sources of freshwater pollution in mining regions. The physicochemical interactions that occur after mixing MWW and MD in a waterway may improve downstream water quality of an impaired reach by reducing downstream concentrations of nutrients and metals (i.e., "co-attenuation"). A first-order stream (Bradley Run in central Pennsylvania), with coal MD and secondarily treated MWW entering the stream in the same location, was systematically monitored to determine in-stream water-quality dynamics. Monitored constituents included pH, nutrients (i.e., phosphorus and nitrogen), and metals (e.g., iron, aluminum, manganese). Mixing of the MWW, MD, and upstream water decreased concentrations of phosphate, aluminum, and iron by 94%, 91%, and 98%, respectively, relative to conservative mixtures at the 1400-m-downstream site. The pollutant co-attenuation resulted in water quality equivalent to that upstream of the pollutant sources and improved the phosphorus-based trophic status of the stream. Geochemical models indicate the primary mechanisms for P attenuation in the studied stream were precipitation as variscite (AlPO4:2H2O) or amorphous AlPO4 plus adsorption to hydrous ferric oxide, despite a much greater abundance of hydrous aluminum oxide. The results presented in this study suggest that in-stream mixing of MD with untreated or secondarily treated MWW may be an important, overlooked factor affecting downstream transport of common pollutants in mining regions. Decreased metals loading and increased pH resulting from natural attenuation and remediation of MD could affect the potential for retention of phosphate by stream sediment and could lead to the release of nutrients from legacy accumulations, highlighting the potential need to address high-nutrient discharges (e.g., improved MWW treatment) in concert with MD remediation.

Making waves: Right in our backyard- surface discharge of untreated wastewater from homes in the United States

Roughly ¼ of U.S. residents (80 million people) lack access to sanitary sewers and are required to treat their wastewater through a permitted onsite wastewater treatment system (OWTS). The vast majority use conventional septic systems with subsurface infiltration, which work well under most conditions. However, certain geologic conditions (e.g., impermeable soil, high water table) can preclude use of septic systems, requiring investment in expensive advanced OWTS. The confluence of lack of sewer, unsuitable geology, and poverty can lead households to have no feasible option for treating wastewater. In many such communities households discharge raw sewage onto the ground through what are commonly called "straight pipes." Here, we present the first effort to synthesize available evidence documenting the scope of straight pipe use in the U.S., including estimates of close to 50% straight pipe use in some counties. Despite reports that straight pipes are widespread and troubling preliminary evidence of adverse health effects, there has been no national effort to estimate the use or impacts of straight pipes. There are various disincentives that discourage the reporting of straight pipes by both residents and government actors. We propose ways to improve quantification of straight pipes and increase knowledge of their adverse effects. We identify the characteristics of areas with large proportions of straight pipes and describe the role of new and pending government programs in encouraging reporting and providing solutions.

Assessing the Socio-Environmental Risk of Onsite Wastewater Treatment Systems to Inform Management Decisions

Quantifying the risk that failing onsite waste treatment systems (OWTS), such as septic systems, present to human health and the environment is a key component in natural resource management. We integrated environmental and socio-demographic data to assess the potential environmental risk and environmental justice concerns related to septic infrastructure. We used this process to develop a framework that can be applied in other jurisdictions. We found only 8% of the registered OWTS presented potential environmental risk due to the topographic, hydrologic, or edaphic characteristics of their placement. In contrast, almost 70% of the OWTS presented potential environmental risk due to their age (25 years or older). Approximately 60% of the OWTS we estimated to be at risk from age or placement were found in census blocks with more than 30% of the population living below the poverty line, had a population that was more than 50% nonwhite, or was predominantly nonwhite and impoverished. Our work suggests that jurisdictions with limited information about septic infrastructure may be able to use geospatial data that they do have to predict the parcel-level locations of OWTS. These locations can then be used to inform environmental monitoring to proactively address environmental justice concerns.

Spatial and Temporal Characterization of Escherichia coli, Suspended Particulate Matter and Land Use Practice Relationships in a Mixed-Land Use Contemporary Watershed

Understanding land use practice induced increases in Escherichia (E.) coli and suspended particulate matter (SPM) concentrations is necessary to improve water quality. Weekly stream water samples were collected from 22 stream gauging sites with varying land use practices in a representative contemporary mixed-land use watershed of the eastern USA. Over the period of one annual year, Escherichia (E.) coli colony forming units (CFU per 100 mL) were compared to suspended particulate matter (SPM) concentrations (mg/L) and land use practices. Agricultural land use sub-catchments comprised elevated E. coli concentrations (avg. 560 CFU per 100 mL) compared to proximate mixed development (avg. 330 CFU per 100 mL) and forested (avg. 206 CFU per 100 mL) sub-catchments. Additionally, agricultural land use showed statistically significant relationships (p < 0.01) between annual E. coli and SPM concentration data. Quarterly PCA biplots displayed temporal variability in land use impacts on E. coli and SPM concentrations, with agricultural land use being closely correlated with both pollutants during Quarters 2 and 3 but not Quarters 1 and 4. The data collected during this investigation advance the understanding of land use impacts on fecal contamination in receiving waters, thereby informing land use managers on the best management practices to reduce exposure risks.

Advancing Understanding of Land Use and Physicochemical Impacts on Fecal Contamination in Mixed-Land-Use Watersheds

Understanding mixed-land-use practices and physicochemical influences on Escherichia (E.) coli concentrations is necessary to improve water quality management and human health. Weekly stream water samples and physicochemical data were collected from 22 stream gauging sites representing varying land use practices in a contemporary Appalachian watershed of the eastern USA. Over the period of one annual year, Escherichia (E.) coli colony forming units (CFU) per 100 mL were compared to physicochemical parameters and land use practices. Annual average E. coli concentration increased by approximately 112% from acid mine drainage (AMD) impacted headwaters to the lower reaches of the watershed (approximate averages of 177 CFU per 100 mL vs. 376 CFU per 100 mL, respectively). Significant Spearman’s correlations (p < 0.05) were identified from analyses of pH and E. coli concentration data representing 77% of sample sites; thus highlighting legacy effects of historic mining (AMD) on microbial water quality. A tipping point of 25–30% mixed development was identified as leading to significant (p < 0.05) negative correlations between chloride and E. coli concentrations. Study results advance understanding of land use and physicochemical impacts on fecal contamination in mixed-land-use watersheds, aiding in the implementation of effective water quality management practices and policies.

Quantifying Escherichia coli and Suspended Particulate Matter Concentrations in a Mixed-Land Use Appalachian Watershed

The relationships between Escherichia (E) coli concentration, suspended particulate matter (SPM) particle size class, and land use practices are important in reducing the bacterium’s persistence and health risks. However, surprisingly few studies have been performed that quantify these relationships. Conceivably, such information would advance mitigation strategies for practices that address specific SPM size classes and, by proxy, E. coli concentration. To advance this needed area of research, stream water was sampled from varying dominant land use practices in West Run Watershed, a representative mixed-land use Appalachian watershed of West Virginia in the eastern USA. Water samples were filtered into three SPM intervals (<5 µm; 5 µm to 60 μm; and >60 μm) and the E. coli concentration (colony forming units, CFU) and SPM of each interval was quantified. Statistically significant relationships were identified between E. coli concentrations and size intervals (α < 0.0001), and SPM (α = 0.05). The results show a predominance (90% of total) of E. coli CFUs in the <5 μm SPM interval. The results show that land use practices impact the relationships between SPM and E. coli concentrations. Future work should include additional combined factors that influence bacterial CFUs and SPM, including hydrology, climate, geochemistry and nutrients.

Movement of traditional fecal indicator bacteria and source-tracking targets through septic drainfields

The past three decades' data on outbreaks in the United States indicate that homes dependent on untreated groundwater (e.g. wells) for household drinking water that are also reliant on onsite treatment of household wastewater (e.g. septic systems) may be at greater risk for waterborne disease. While groundwater quality monitoring to protect public health has traditionally focused on the detection of fecal indicator bacteria, the application of emerging source tracking strategies may offer a more efficient means to identify pollution sources and effective means of remediation. This study compares the movement of common fecal indicator bacteria (E. coli and enterococci) with a chemical (optical brighteners, OB) and a molecular (Bacteroides HF183) source tracking (ST) target in small scale septic drainfield models in order to evaluate their potential utility in groundwater monitoring. Nine PVC column drainfield models received synchronized doses of primary-treated wastewater twice daily, with influent and effluent monitored bi-weekly over a 7-month period for all targets. Results indicate that E. coli and enterococci concentrations were strongly associated (Spearman's rank, p<0.05), and correlations between enterococci and optical brighteners were moderately strong. Bacteroides HF183 was significantly, but not strongly, associated with optical brighteners and both indicator bacteria (Point-biserial correlation, p<0.05), most likely due to its sporadic detection. Application of human ST marker monitoring in groundwaters at risk of contamination by human sewage is recommended, although consistent interpretation of results will rely on more detailed evaluation of HF183 incidence in source contamination waters.