Environmental Protection Agency's Level Research Articles

A machine learning model for estimating the temperature of small rivers using satellite-based spatial data

The influence of anthropogenic activity and land cover alteration on stream temperatures has major ecological implications, such as limiting fish survival. While these ecological impacts have been extensively studied at varying spatial scales for major rivers, our understanding of the range and complexity of this relationship across climates and geographies for smaller rivers (less than ∼60 m wide) remains limited. This is in part because although such rivers comprise a vast majority (∼97%) of total stream length, most smaller rivers lack routine temperature observations despite extensive gage networks. While existing gage networks in many regions are sufficient to support satellite remote sensing-based modeling of small stream temperatures, most large regions including the contiguous United States do not have modeled data products at high spatial and temporal resolution for small rivers.In this study, we developed a statistical model, TempEst (“temperature estimation”), to estimate monthly average water temperatures for smaller rivers and evaluated the model with rivers ranging from 3 m to 1000 m (1 km) in width, using land cover, topography, and satellite-based land surface temperature. The rivers chosen for development of the model are representative of a range of urban and rural land uses and cover eight US Environmental Protection Agency Level I ecoregions. The model was calibrated and validated using observed stream temperatures from the United States Geological Survey. TempEst is able to predict monthly average temperature for streams of any size with an overall median RMSE of about 1.5 °C and bias of 0%. Model accuracy has a consistent trend with training gauge network density, with median RMSE increasing to about 2.0 °C in more sparsely-gauged regions. As a simple demonstration, we used TempEst to estimate thermal suitability conditions for cutthroat trout in Rocky Mountain streams in the United States. The developed model, available as open-source R (model) and Google Earth Engine (data retrieval) scripts, will facilitate the study of stream temperature behaviors at higher resolutions than previously available across the contiguous United States and can be easily adapted to support global river systems.

Flow-based compact microfluidic electrochemical cell with Parafilm® channels

A planar interdigitated microelectrodes-based microfluidic electrochemical cell (P-μFEC) with channels made by Parafilm® sheets was conceptualized with the application as a sensor for detecting heavy metal ions. Herein, we first-timely proposed a new strategy for creating Parafilm® microchannels using a Plotter cutter and Hot bonding self-sealing method for solid Microfluidic devices (PPHM). For the prepared novel P-µFEC by the PPHM protocol, which operated in the laminar regime, its electrochemical performance was well-studied using the well-known electrochemical reporter potassium Ferri/Ferrocyanide (K3/K4[Fe(CN)6]). A reference electrode (RE) layer deposited at the top silica glass substrate was embedded within the device to minimize the ohmic drop (iRcell) between the working electrode (WE) and RE. The experimental and virtualized computational COMSOL results demonstrated: (i) The changes in the RE's placements had negligible influences on the P-µFEC's electrochemical performance. (ii) The laminar flow's influence on the P-µFEC's electrochemical performance was quite prominent, which was due to the changes in the mass transfer process from diffusion (stationary) to diffusion + convection (hydrodynamic). (iii) A direct virtualized demonstration of laminar flow's influences on the mass transfer process from diffusion (stationary) to diffusion + convection (hydrodynamic) was first timely validated by finite element analysis simulation using COMSOL Multiphysics. (iv) Finally, the proposed P-µFEC showed promise as a sensitive electrochemical sensor for different heavy metal ion substrate (model analytes) detection. The IUPAC detection limits for Cu2+, Pb2+, [Fe(CN)6]3- and Hg2+ is ∼318.6±3.55 μg/L, ∼191±5.4 4 μg/L, ∼113.5±9.9 μg/L, and 8.21±0.88 μg/L, respectively. Among them, the detection limit for Cu2+ and Hg2+ meets the US Environmental Protection Agency (EPA)'s water contamination level for Cu (1300 μg/L) and is close to the EPA level for Hg (2 μg/L), respectively. These findings demonstrate the potential of using the Parafilm® sheet as the microfluidic channel for a flow-based P-μFEC as a novel analytical tool.

A Quantitative Comparison of Heavy Metal Concentrations in the Soils on Two Rocky Mountain West tribal Reservations

Native Americans have experienced a long history of environmental injustice, including natural resource exploitation and commercial activity with environmental impacts. A community-based participatory research (CBPR) approach was used to partner with two Rocky Mountain West reservations to conduct pilot-level assessments of potential soil contamination by heavy metals. The Community Advisory Board in conjunction with the research team selected residential areas and community sites for sampling. Samples were obtained, transported to a laboratory for dehydration and sieving, and were analyzed with a handheld X-ray fluorescence (XRF) tool for the presence of 24 heavy metals. Heavy metals concentrations were compared between reservations and were found to be statistically different from one another. Findings were also compared to levels recommended by the Environmental Protection Agency (EPA) and World Health Organization (WHO) to determine possible hazards to human health. Concentration of Sr, Rb, and Th were well above acceptable EPA levels and require further analysis. High localized Pb levels were found in one area, while Hg levels were found close to EPA standards. CBPR was essential to understanding preliminary contamination patterns. In conclusion, even reservations with similar geographies and histories present with unique contaminations and require individualized study to determine possible environmental mitigation.

A216 EXAMINING THE EFFECTS OF GLYPHOSATE EXPOSURE ON THE GUT BACTERIOME AND INFLAMMATION IN A MURINE MODEL OF COLITIS

Abstract Background Canada has the highest incidence of inflammatory bowel disease in the world, which is expected to rise unabated for the next 30 years. Coincidently, Canada is one of the most prolific users of the herbicide glyphosate (tradename Roundup®), with over 25 million kilograms purchased annually. Previous studies examining the effects of glyphosate on the gut bacteriome have used high levels of glyphosate (ranging from 2.5mg – 25mg/kg bw/day) and have yielded conflicting results. Our goal is to examine the effects of dietary levels of glyphosate on the gut microbiome and inflammation in an animal model of colitis. Two environmentally relevant doses were explored: (1) the acceptable daily intake currently set by the Environmental Protection Agency (EPA) (1.75mg/kg bw/day) and (2) North American dose, calculated by a registered dietician using literature values of glyphosate found within food products (0.1mg/kg bw/day.) Aims 1) To determine if glyphosate exposure influences intestinal permeability 2) To determine if glyphosate exposure influences intestinal inflammation 3) To determine if glyphosate exposure influences colitis onset and severity. We hypothesized that exposure to glyphosate leads to bacterial dysbiosis, increased intestinal permeability and increased severity of colitis in Mucin 2 deficient mice (Muc2-/-mice). Methods Upon weaning, Muc2-/- mice were exposed to glyphosate through their drinking water. Animals were monitored weekly for clinical signs of colitis, including rectal prolapse. Following 12-week glyphosate exposure, intestinal permeability was measured using the FITC-dextran permeability assay. Intestinal inflammation was measured using qPCR and markers relevant to our animal model including REGIIIγ, RELM-β and CLEC-2. Results Exposure to glyphosate at physiologically relevant levels does not increase intestinal permeability in Muc2-/-mice, with all groups showing equal levels of FITC-dextran present within their serum. Animals exposed to the EPA dose of glyphosate exhibited earlier onset of colitis symptoms with animals receiving higher clinical scores and displaying an increased rate of rectal prolapse. Animals exposed to the EPA dose also showed a significant increase in CLEC-2 expression. CLEC-2 is a C-type lectin-like receptor expressed by immune cells and platelets and has been implicated in tumor metastasis. Additionally, overexpression of CLEC-2 has been shown to promote pathogen adherence to mammalian cells. Conclusions Exposure to glyphosate at levels deemed safe by the EPA increases colitis onset and severity in Muc2-/- deficient animals. Additionally, EPA level glyphosate exposure upregulates CLEC-2 expression which may have implications for tumor development and increased enteropathogenic infections. Funding Agencies CCCCrowdfunding, NSERC

Predictors and Spatial Variation of Radon Testing in Illinois, 2005-2012.

Radon is the second leading cause of lung cancer, but exposure can be reduced through testing one's home and mitigating if levels are high. To determine what factors predict radon testing and to identify, through spatial analysis, areas in Illinois with lower or higher than expected testing rates. An ecological study design was used to evaluate data on radon tests performed in Illinois by a licensed professional or a home radon test kit analyzed by a state-approved laboratory between 2005 and 2012. Zip code-level rates of testing per 1000 occupied residences were calculated for all testing methods combined and for licensed professional testing and home kit testing separately. The following zip code-level factors associated with radon testing were considered: Environmental Protection Agency (EPA) radon zones (ie, categorization of areas by predicted radon risk), socioeconomic characteristics, homeowner occupancy, and rurality. Univariate and multivariable incidence rate ratios were calculated to examine what factors were associated with each testing type. Hotspot analysis was performed to identify zip codes with lower than expected and higher than expected testing rates (ie, "coldspots" and "hotspots," respectively). Radon testing rates varied across EPA zone, socioeconomic characteristics, and level of rurality. In multivariable analysis, EPA zone, education, and median household income positively predicted all testing types combined. Median home value was associated with licensed testing, whereas rurality was negatively associated with licensed testing. Owner occupancy positively predicted home kit testing. Between 19.6% and 31.1% of zip codes were coldspots for radon testing rates, dependent upon testing type. Coldspots of all testing method rates were concentrated in the southern part of the state. Public health professionals can benefit from understanding what area-level factors predict radon testing and what geographic areas may under-utilize testing. Such information can aid the development of geographically targeted, cost-effective interventions that increase radon testing and subsequently reduce lung cancer risk.

Noise Pollution and Health Effects

Background: Noise pollution is of particular importance due to the physical and psychological effects on humans. Noise is a stressor that affects the autonomic nervous system and the endocrine system. Noise is also a threat to marine and terrestrial ecosystems. Health risks from noise are correlated with road traffic. In other words, noise health effects are the health consequences of elevated sound levels. Objectives: This study aims to determine the effect of noise pollution (near roadways) on health issues in Ahvaz, Iran. Materials and Methods: In this cross-sectional study, equivalent sound pressure level were measured by sound level meters TES-1353 in 75 locations around 4 roadways, which had a high load of traffic in Ahvaz City during day time. During the study, 820 measurements were recorded at measuring stations, for 7 days per week with 1-hour interval between each measurement. Statistical analysis was carried out by SPSS software. Results: According to the research findings, the equivalent sound pressure levels in all stations were 76.28 ± 3.12 dB (Mean ± SD). According to sound measurements and the survey questionnaire, noise pollution is higher than EPA (US Environmental Protection Agency) and Iran standard level. Based on result of this study the worst noise health effects were the nervousness and sleep quality during 2012. Conclusions: According to the results of this study, with increasing load of traffic, there is an increasing need for proper consideration plans to control noise pollution and prevent its effects.

The geography of mercury and PCBs in North Carolina’s local seafood

Mercury and PCBs are used by non-governmental organizations and federal agencies to inform seafood safety recommendations. Pollution dynamics suggest recommendations on the national scale may be too large to be accurate. We tested softshell and hardshell blue crab, white and pink shrimp, oysters, clams, spot, and mullet from fishers in each of the three North Carolina fishery districts. We measured mercury using EPA method 7473 and PCBs using a commercially available ELISA kit. Over 97% of samples were below the Environmental Protection Agency levels of concern for both mercury and PCBs. Mercury and PCBs have different spatial dynamics, but both differ significantly by water body, suggesting that seafood safety recommendations should occur by water body instead of at the national scale. This finding supports previous research suggesting that differences in water chemistry, terrestrial influence, and flushing time in a particular water body control the contaminant load in locally resident species.

Solid-phase extraction and sample stacking–capillary electrophoresis for the determination of quaternary ammonium herbicides in drinking water

Conditions for the simultaneous determination of paraquat, diquat and difenzoquat by capillary zone electrophoresis were established by combining two preconcentration procedures. Off-line solid-phase extraction was used for the isolation and preconcentration of quats in drinking water. Quats were then analysed by capillary electrophoresis using sample stacking with matrix removal as on-column preconcentration procedure. Two different porous graphitic carbon cartridges were compared. The breakthrough volumes of the three herbicides were calculated and the loading capacity of the sorbents was compared. Recoveries higher than 80% for difenzoquat and around 40% for paraquat and diquat were obtained when a sample volume of 250 ml was percolated. For the stacking–capillary electrophoresis analysis of quats, 50 m M acetic acid–ammonium acetate (pH 4.0), 0.8 m M cetyltrimethylammonium bromide with 5% (v/v) methanol as carrier electrolyte was used. Detection limits, based on a signal-to-noise ratio of 3:1, were lower than 0.3 μg l −1 for standards in Milli-Q water, and lower than 2.2 μg l −1 for drinking water samples. Run-to-run and day-to-day precision of the method were established. The two preconcentration procedures used together was successfully applied to the analysis of the three herbicides in spiked drinking water at concentrations below the maximum admissible US Environmental Protection Agency levels.

Is nonoccupational noise exposure negligible?

According to the Environmental Protection Agency's levels document (EPA, 1974), a daily noise exposure that does not exceed an Leq(24), of 70 dB can be considered, with an adequate margin of safety, a “safe exposure.” Furthermore, they suggested that restricting occupational noise exposure to an Leq(8), of 75 dB would be sufficient to protect the public since that would still result in an Leq(24), of 70 dB, provided that nonoccupational noise exposure is negligible? But is nonoccupational exposure negligible? Probably not. In this investigation, the noise exposure of 50 individuals was continuously monitored over seven consecutive days, by means of personal noise dosimeters. And, at least among these individuals, nonoccupational exposure was not negligible. In fact, when sleeping time was accounted for, nonoccupational noise exposure was often more significant than occupational exposure. [Work supported by USAF and EPA.]