Environmental Protection Agency Water Quality Research Articles

The Effects of Annual Compost Addition to Agricultural Green Roofs on Runoff Water Quality

Space availability is one of the largest barriers to urban agriculture. One way around this issue that urban farmers in some parts of the world are exploring is moving their farming activities to building rooftops. One method of rooftop farming in use is row agriculture using green roof technology. Vegetable crop plants, which typically require more water and more nutrients than the ornamental species found on green roofs, require irrigation and the use of fertilizers. One nutrient management practice that some rooftop farmers are using is the addition of compost, which could lead to changes over time in the water-holding capacity, organic matter content, and weight of green roof media. This practice and its long-term implications have not been well-studied. Green roof platforms were created to examine how the annual additions of compost in quantities of 0, 0.33, 0.66, and 1 kg/m2 affect runoff water quality and green roof media properties. Runoff water samples were collected and analyzed for pH, conductivity, color, turbidity, and nitrate nitrogen, ammonia nitrogen, total phosphorus, and potassium contents. Compost treatment had no effect on any water quality metric except for color, which had slightly different changes over time in the different compost treatments. The lack of difference among the treatments may be attributed to the low nutrient content of the compost and continued use of fertilizers to provide nutrients. Most samples observed in this study exceeded the US Environmental Protection Agency water quality guidelines for nitrate nitrogen and phosphorus and were similar to values observed in the green roof literature regarding agricultural and ornamental green roofs. This has potential implications for surface water quality and eutrophication, especially as green roof agriculture increases.

MassWateR: Improving quality control, analysis, and sharing of water quality data.

The long-term protection and restoration of aquatic resources depends on robust monitoring data; data that require systematic quality control and analysis tools. The MassWateR R package facilitates quality control, analysis, and data sharing for discrete surface water quality data collected by monitoring programs of various size and technical capacity. The tools were developed to address regional needs for programs in Massachusetts, USA, but the principles and outputs can be applicable to monitoring data collected anywhere. Users can create quality control reports, perform outlier analyses, and assess trends by season, date, and site for more than 40 parameters. Users can also prepare data for submission to the United States Environmental Protection Agency Water Quality Exchange, thus sharing data to the largest water quality database in the United States. The automated and reproducible workflow offered by MassWateR is expected to increase the quantity and quality of publicly available data to support the management of aquatic resources.

Impacts of urbanization on chloride and stream invertebrates: A 10-year citizen science field study of road salt in stormwater runoff.

The use of deicing agents during the winter months is one of many stressors that impact stream ecosystems in urban and urbanizing watersheds. In this study, a long-term data set collected by citizen scientists with the Missouri Stream Team was used to evaluate the relationships between watershed urbanization metrics and chloride metrics. Further, these data were used to explore the effects of elevated chloride concentrations on stream invertebrate communities using quantile regression. While the amount of road surface in a watershed was a dominant factor in predicting the maximum chloride measurement, the median chloride concentration was also strongly related to the amount of medium-to-high density development in the watershed, suggesting that nonmunicipal salt use is an important contributor to increases in base flow chloride concentrations. Additionally, chloride concentration appears to be one of the many factors that impact invertebrate density and diversity measurements, with decreases in invertebrate diversity corresponding with the US Environmental Protection Agency water quality criteria. Our findings suggest that the use of chloride-based road salt on municipal roads as well as on nonmunicipal settings is contributing to a loss of diversity and density of aquatic invertebrate communities in urban regions. Integr Environ Assess Manag 2022;18:1667-1677. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Calculating Aqueous Environmental Quality Standards to Protect Human Health: Derivation of a Predicted No-Effect Concentration.

Efforts to establish water quality standards for the protection of human health involve a calculation of the amount of fish that can be consumed without exceeding a predetermined safe dose. This article is protected by copyright. All rights reserved.

Toxicity of Aluminum to Ceriodaphnia dubia in Low-Hardness Waters as Affected by Natural Dissolved Organic Matter.

We conducted a series of 7-d toxicity tests with Ceriodaphnia dubia in dilutions of low-hardness natural waters, which contained dissolved organic carbon (DOC) concentrations up to 10 mg/L. Stream waters were mixed with well water to achieve 2 target hardness levels (20 and 35 mg/L) and 4 DOC concentrations. Tests with aluminum (Al)-spiked waters were conducted in a controlled CO2 atmosphere to maintain the pH at a range of 6.0 to 6.5. The results were used to estimate effect concentrations for survival and reproduction, expressed as total (unfiltered) Al concentrations. There were small differences in total-Al thresholds between waters with 20 and 35 mg/L hardness, but effect concentrations for C. dubia survival (median lethal concentrations) and reproduction (effect concentrations, 20%) increased log-linearly with increasing DOC concentrations in the range, 0.3 to 6 mg/L. Slopes of these regressions were similar to slopes from data used to revise the US Environmental Protection Agency water quality criterion for Al, but toxic effects in the present study occurred at total-Al concentrations 8- to 10-fold greater than toxicity values used for criteria development. This difference probably reflects the long equilibration (aging) times of Al test waters used in the present study (up to 192 h) compared with short (3-h) equilibration times in other studies used for criteria development. These results confirm the importance of DOC as a control on Al toxicity in low-hardness waters, but they also demonstrate that total-Al concentrations are not predictive of Al toxicity, except under defined water quality (pH, hardness, DOC) and exposure conditions (e.g., aging of test waters). Environ Toxicol Chem 2019;38:2121-2127. Published 2019 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America.

Nickel toxicity in wood frog tadpoles: Bioaccumulation and sublethal effects on body condition, food consumption, activity, and chemosensory function.

Nickel (Ni) concentrations in aquatic ecosystems can be amplified by anthropogenic activities including resource extraction. Compared with fish and invertebrates, knowledge of Ni toxicity in amphibians is limited, especially for northern species. We examined the effect of Ni on wood frog (Lithobates sylvaticus) tadpoles, the species with the widest and most northern distribution of any anuran in North America. Wood frog tadpoles were exposed to a Ni concentration gradient (0.02-5.5 mg/L of Ni at 164 mg/L as CaCO3 water hardness) for 8 d and examined for lethality, Ni bioaccumulation, and several sublethal endpoints including body condition, food consumption, activity, and chemosensory function. Nickel induced a sublethal effect on body condition (8-d 10 and 20% effect concentrations [EC10 and EC20] of 1.07 ± 0.38 and 2.44 ± 0.51 mg/L of Ni ± standard error [SE], respectively) but not on food consumption, activity, or chemosensory function. Nickel accumulation in tadpole tissues was positively related to an increase in aqueous Ni concentration but was not lethal. Both the acute and chronic US Environmental Protection Agency water quality guideline concentrations for Ni (0.71 and 0.08 mg/L at 164 mg/L as CaCO3 water hardness, respectively) were protective against lethal and sublethal effects in wood frog tadpoles. In the present study, wood frog tadpoles were protected by current water quality guidelines for Ni and are likely not as useful as other taxa for environmental effects monitoring for this particular metal. Environ Toxicol Chem 2018;37:2458-2466. © 2018 SETAC.

Terra incognita: The unknown risks to environmental quality posed by the spatial distribution and abundance of concentrated animal feeding operations

Concentrated animal feeding operations (CAFOs) pose wide ranging environmental risks to many parts of the US and across the globe, but datasets for CAFO risk assessments are not readily available. Within the United States, some of the greatest concentrations of CAFOs occur in North Carolina. It is also one of the only states with publicly accessible location data for classes of CAFOs that are required to obtain water quality permits from the U.S. Environmental Protection Agency (EPA); however, there are no public data sources for the large number of CAFOs that do not require EPA water quality permits. We combined public records of CAFO locations with data collected in North Carolina by the Waterkeeper and Riverkeeper Alliances to examine the distribution of both permitted and non-permitted CAFOs across the state. Over half (55%) of the state's 6646 CAFOs are located in the Coastal Plain, a low-lying region vulnerable to flooding associated with regular cyclonic and convective storms. We identified 19% of CAFOs ≤ 100 m of the nearest stream, and some as close as 15 m to the nearest stream, a common riparian buffer width for water quality management. Future climate scenarios suggest large storm events are expected to become increasingly extreme, and dry interstorm periods could lengthen. Such extremes could exacerbate the environmental impacts of CAFOs. Understanding the potential impacts of CAFO agroecosystems will require remote sensing to identify CAFOs, fieldwork to determine the extent of environmental footprints, and modeling to identify thresholds that determine environmental risk under changing conditions.

Structural and functional responses of periphyton and macroinvertebrate communities to ferric Fe, Cu, and Zn in stream mesocosms.

Two mesocosm experiments were conducted to examine effects of ferric iron (Fe) and mixtures of ferric Fe with aqueous metals (Cu, Zn) on stream benthic communities. Naturally colonized benthic communities were exposed to a gradient of ferric Fe (0, 0.4, 1.0, 2.5, 6.2, and 15.6 mg/L) that bracketed the current US Environmental Protection Agency water quality criterion value (1.0 mg/L). After 10 d of exposure to ferric Fe, total macroinvertebrate abundance, number of taxa, and abundance of all major macroinvertebrate groups (Ephemeroptera, Plecoptera, Trichoptera, and Diptera) were significantly reduced. Heptageniid mayflies and chironomids were especially sensitive to Fe oxide deposition and were significantly reduced at 0.4 and 1.0 mg/L total Fe, respectively. In a second mesocosm experiment, periphyton and macroinvertebrate communities were exposed to ferric Fe (0.60 mg/L) with or without aqueous Cu and Zn at 2 treatment levels: low (0.01 mg/L Cu + 0.1 mg/L Zn) and high (0.05 mg/L Cu + 0.5 mg/L Zn). In contrast to previous research, we observed no evidence of a protective effect of Fe on toxicity of metals. Growth rates and protein content of periphyton were significantly reduced by both ferric Fe and aqueous metals, whereas abundance of heptageniid mayflies (Cinygmula) and whole community metabolism were significantly reduced by ferric Fe alone. We hypothesize that Fe oxides inhibited algal growth and enhanced metal accumulation, leading to a reduction in the quantity and quality of food resources for grazers. Mesocosm experiments conducted using natural benthic communities provide a unique opportunity to quantify the relative importance of indirect physical effects and to develop a better understanding of the relationship between basal food resources and consumers in natural stream ecosystems. Environ Toxicol Chem 2018;37:1320-1329. © 2017 SETAC.

Performance of a hybrid pilot-scale constructed wetland system for treating oil sands process-affected water from the Athabasca oil sands

Mining leases in the Athabasca oil sands (AOS; near Ft. McMurray, Canada) produce large volumes of oil sands process-affected water (OSPW) that contain potentially problematic constituents requiring treatment prior to surface water discharge into receiving aquatic systems. The aim of this research was to identify constituents of concern (COCs) in OSPW sourced from an AOS external tailings facility and design a hybrid pilot-scale constructed wetland treatment systems (CWTS) to decrease concentrations of COCs and subsequently mitigate risks. COCs were identified based on comparisons to ambient water quality thresholds for the protection of aquatic life (i.e. Canadian Environmental Quality Guidelines [CEQGs], Alberta Environment Water Quality Guidelines [Alberta WQGs], and United States Environmental Protection Agency Water Quality Criteria [USEPA WQC]) and toxicity endpoints. Performance of the hybrid pilot-scale CWTS was evaluated by rate and extent of COC removal and change in toxicity as measured by an aquatic invertebrate Ceriodaphnia dubia. Following characterization of OSPW, specific COCs were identified as: naphthenic acids (NAs), oil and grease (O/G), metals/metalloids (Al, B, Cu, Ni, Se, and Zn), chloride, and total suspended solids (TSS). A hybrid pilot-scale CWTS was designed to promote treatment processes to alter (transfer and transform) COCs using sequential reducing and oxidizing wetland reactors and a solar photocatalytic treatment reactor using fixed film titanium dioxide (TiO2). Performance criteria were achieved as the CWTS decreased concentrations of NAs, O/G, and metals below protective thresholds and decreased toxicity to C. dubia. Results from this study provide proof-of-concept data to inform hybrid passive or semi-passive treatment approaches (i.e. constructed wetlands) that could be used to mitigate COCs contained in OSPWs.

Effect of Fe (III) on Pseudokirchneriella subcapitata at circumneutral pH in standard laboratory tests is explained by nutrient sequestration.

The complex chemistry of iron (Fe) at circumneutral pH in oxygenated waters and the poor correlation between ecotoxicity results in laboratory and natural waters have led to regulatory approaches for iron based on field studies (US Environmental Protection Agency Water Quality Criteria and European Union Water Framework Directive proposal for Fe). The results of the present study account for the observed differences between laboratory and field observations for Fe toxicity to algae (Pseudokirchneriella subcapitata). Results from standard 72-h assays with Fe at pH 6.3 and pH 8 resulted in similar toxicity values measured as algal biomass, with 50% effect concentrations (EC50) of 3.28 mg/L and 4.95 mg/L total Fe(III), respectively. At the end of the 72-h exposure, however, dissolved Fe concentrations were lower than 30 μg/L for all test concentrations, making a direct toxic effect of dissolved iron on algae unlikely. Analysis of nutrient concentrations in the artificial test media detected phosphorus depletion in a dose-dependent manner that correlated well with algal toxicity. Subsequent experiments adding excess phosphorus after Fe precipitation eliminated the toxicity. These results strongly suggest that observed Fe(III) toxicity on algae in laboratory conditions is a secondary effect of phosphorous depletion. Environ Toxicol Chem 2017;36:952-958. © 2016 SETAC.

Physico-chemical and radon analysis of drinking water available in Samtah-Jazan city Southwest of Saudia Arabia

In order to understand the quality of drinking water (tap water, gallon water, and mineral water) supply in Samtah-Jazan city southwest of Saudi Arabia, physicochemical characteristics were studied and analyzed. Water samples were carefully collected for various physicochemical parameters, such as turbidity, water temperature, pH, conductivity, total alkalinity, total hardness, chloride, iron and radon had been analyzed using standard procedures and compared with World Health Organization Standards, Saudi Arabian Specification Standards, and United States Environmental Protection Agency water quality guidelines. The bacterial parameters were analyzed for total count of bacteria, E. Coli bacteria and fecal coliform. It was approved that no bacterial contamination present in the water samples. The results revealed that all of the parameters were in normal range and indicated safety and suitability for drinking purposes.

Suspended sediment supply dominated by bank erosion in a low-gradient agricultural watershed, Wildcat Slough, Fisher, Illinois, United States

The relative contributions from potential sediment sources to the suspended load of the Wildcat Slough, a headwater tributary in central Illinois, are estimated as a proxy for understanding sediment and nutrient transport in low gradient, intensively managed watersheds. Sediment and nutrient fluxes from agricultural areas to rivers have led to nitrate (NO3) concentrations that exceed US Environmental Protection Agency water quality standards and phosphorus (P) concentrations that promote algal growth, decreasing water quality across the state of Illinois. This study assesses contributions to the sediment load as a function of land use and channel morphology in Wildcat Slough, a low gradient, intensively managed 61.3 km2 (23.67 mi2) watershed in the Upper Sangamon River Basin of central Illinois, United States. Land use is dominated by row crop agriculture. Potential sediment sources include row crop fields, forest, floodplains, river banks, pastures, and grasslands. The majority of the stream is constrained within a deep, channelized ditch fed by tile drains. However, in the lowermost reaches, Wildcat Slough freely meanders and has established fluvial features including point bars and cut banks. A suite of tracers (delta carbon 13 [δ13C], phosphorus [P], magnesium [Mg], manganese [Mn], and carbon [C]) differ significantly between the potential sediment sources. An unmixing model uses the concentrations of the tracers in source samples and in suspended sediment collected during high discharge events to estimate the relative contribution from each source to the suspended load. The majority of suspended sediment was sourced from channel banks (40% to 65%) and forest (35% to 55%) with very little derived from the agricultural uplands (10% or less). The lack of sediment from uplands signifies a disconnect between the uplands and the channel, reflecting the low relief of the uplands and the dominance of tile drains in routing water to the channel. These findings suggest that efforts to limit the sediment-born nutrient load should focus on near-channel areas in meandering reaches. Best practices in similar landscapes may include installation of a buffer between meandering channel reaches and fertilized land, or limiting fertilizer application near channel banks, to diminish the inputs to the nutrient load via natural channel migration.

Spatial assessment of water quality in the vicinity of Lake Alice National Wildlife Refuge, Upper Devils Lake Basin, North Dakota.

Runoff from concentrated animal feeding operations and croplands in the Upper Devils Lake Basin (Towner and Ramsey Counties), North Dakota, has the potential to impact the water quality and wildlife of the Lake Alice National Wildlife Refuge. Water samples were collected at eight locations upstream and downstream of the refuge, beginning in June 2007 through March 2011, to identify the spatial distribution of water quality parameters and assess the potential impacts from the upstream land use practices. Geographic Information Systems, statistical analysis, and regulatory standards were used to differentiate between sample locations, and identify potential impacts to water quality for the refuge based on 20 chemical constituents. Kruskal-Wallis analysis of variance (ANOVA) showed significant differences between sample locations based on boron, calcium, Escherichia coli, phosphorus, aluminum, manganese, and nickel. Hierarchical agglomerative cluster analysis of these constituents identified four distinct water quality groupings in the study area. Furthermore, this study found a significant positive correlation between the nutrient measures of nitrate-nitrite and total Kjeldahl nitrogen, and the percentage of concentrated animal feeding operation nutrient management areas using the non-parametric Spearman rho method. Significant correlations were also noted between total organic carbon and nearness to concentrated animal feeding operations. Finally, dissolved oxygen, pH, sulfate, E. coli, total phosphorus, nitrate-nitrite, and aluminum exceeded state of North Dakota and/or US Environmental Protection Agency water quality standards and/or guidelines. Elevated concentrations of phosphorus, nitrate-nitrite, and E. coli from upstream sources likely have the greatest potential impact on the Lake Alice Refuge.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in water and six fish species from Dongting Lake, China

There have been few studies of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in environmental water because of the large volume of water required for PCDD/Fs analysis. Water quality directly affects aquatic organisms, and little is known about how PCDD/Fs are transported in aquatic environments. PCDD/Fs were analyzed in eight water samples from Dongting Lake, China, which was contaminated with PCDD/Fs because of sodium pentachlorophenate use between the 1960s and the 1980s. The total PCDD/F concentrations in the samples were 36–345pgL−1, and the mean was 191pgL−1. Octachlorodibenzo-p-dioxin was the most abundant PCDD/F congener in every sample, contributing 67–95% of the total 2,3,7,8-chlorinated PCDD/F concentrations. The toxic equivalent (WHO-TEQ) concentrations in the samples were 0.17–0.37pgL−1, and the mean was 0.28pgL−1, which is higher than the Canadian environmental quality guideline (0.038pgL−1 WHO-TEQ for freshwater) and the United States Environmental Protection Agency water quality criterion (0.014pgL−1 WHO-TEQ). PCDD/Fs were also determined in six fish species collected from Dongting Lake, to assess the concentrations, accumulation patterns, and potential for toxic effects. The total 2,3,7,8-chlorinated PCDD/F concentrations in the fish samples were 2.2–17.9pgg−1 (wet weight), and the dominant congeners were octachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin, and 2,3,4,7,8-pentachlorodibenzofuran. The PCDD/F WHO-TEQs were 0.10–0.92ww (3.3–65.3lw) pgg−1 in different species of fish. PCDD/F congener patterns in fish may be affected by food chain biomagnification and the lipid content of the species.

Annual and seasonal variation of turbidity, total dissolved solids, nitrate and nitrite in the Parsabad water treatment plant, Iran

Aims: This study investigated the annual and seasonal variation of turbidity; total dissolved solid (TDS), nitrate and nitrite in Parsabad water treatment plant (WTP), Iran. Materials and Methods: The water samples were obtained from the inlet and outlet of Parsabad WTP from February 2002 to June 2009. The samples' turbidity, TDS, nitrate, nitrite, pH, and temperature were measured according to standard methods once a month and the average of these parameters were calculated for each season of year. Results: The maximum concentration of inlet turbidity, TDS, nitrate and nitrite were 691, 700.5, 25, and 0.17 mg/l, respectively. These parameters for outlet samples in the study period were 3.0, 696.7, 18, and 0.06 mg/l, respectively. While these concentrations in outlet zone were lower than World Health Organization (WHO) or United States Environmental Protection Agency (US-EPA) water quality guidelines, WTP could not reduce the TDS, nitrate, nitrite and pH value and these parameters were not different in the inlet and outlet samples. However, the WTP reduced the turbidity significantly with an efficiency of up to 85%. Conclusion: This study showed that a common WTP with rapid sand filtration can treat a maximum river turbidity of 700 NTU in several years. As no differences were observed between inlet and outlet TDS, nitrate, nitrite and pH in the studied WTP. It can be concluded that compensatory schemes should be predicted for modification of these parameters when they exceed the standards in the emergency situations.

Current Wet Persulfate Digestion Method Considerably Underestimates Total Phosphorus Content in Natural Waters

T phosphorus (TP) in river and lake water is an important environmental variable that can be used as an indicator of nutrient status and water quality. TP was recently selected as an environmental stressor and numeric criteria have been developed based on its background concentration in a given environment. To minimize the eutrophication risk in aquatic ecosystems, U.S. Environmental Protection Agency water quality criteria require that TP is not exceed 10−128 μg/L for river and streams. Following EPA method 365.1, TP in surface waters is routinely determined on unfiltered water samples that are digested by autoclave in the presence of persulfate. Recent studies, however, indicated this method suffers low recovery of particulate phosphorus (PP) and we suggest reliable high temperature combustion method be used for PP determination. Raw water samples contain both suspended particles and dissolved constituents. In EPA TP method 365.1, unfiltered water sample is used for persulfate digestion but no attention was given on how to keep sample homogeneous and representative to the field condition. Due to rapid settling of large particles in water sample containers, it is difficult to keep sample homogeneous during subsampling and analysis. For example, it is practically impossible to avoid particle settling when samples are seating in an autosampler during automated online digestion and analysis. TP consists of particulate phosphorus and total dissolved phosphorus (TP = PP + TDP). Because most TP resides in particulate phase loss of particles during sampling and analysis can result in a significantly underestimated TP. To obtain representative particulate samples, filtration through 0.45 μm pore size filters has been used to separate PP from TDP (it might require a large volume of water if water turbidity is low). Particles collected on the filters are used to determine the PP. The filtrates are used to determine dissolved inorganic phosphorus (DIP) and TDP. The difference between TDP and DIP is operationally defined as dissolved organic P (DOP). The sum of PP and TDP can provide an accurate estimate of TP in natural waters. DOP and PP are usually converted to DIP which can then be measured by the molybdenum blue method. Wet persulfate digestion has been widely used for digesting TDP samples with variable conversion efficiency for different DOP compounds, ranging from 66% for inositol phosphate to 100% for ADP. On the other hand, high temperature combustion is needed for PP determination. High temperature combustion at above 550 °C can decompose all organic matters and inorganic minerals to simple inorganic compounds. With commercial CHN elemental analyzer available, it has become a conventional technique for measuring carbon, hydrogen and nitrogen content of particulate samples. In PP determination, high temperature combustion in the presence of oxidizing reagent Mg(NO3)2 was followed by acid extraction to recover DIP. This method has been used for analysis of PP in sediment and TDP in water samples and achieved a close to 100% conversion efficiency. However, no commercial P elemental analyzer is available and manual analysis of PP by high temperature combustion remains time-consuming and labor-intensive. It is worth to note that the first persulfate digestion method developed by Menzel and Corwin in 1965 was for measuring seawater TP. In that study, only a few DOP compounds were tested for recovery. A dried zooplankton tissue was suspended in distilled water and then the filtrate from the suspension was analyzed by persulfate digestion method. This extracted, filtered sample contained only DOP and no PP sample was tested. Ironically, this seawater method become obsolete in marine community has since been widely adapted for TP measurement in freshwater where particulate matter, dominated by clay minerals, is much more abundant than oceanic waters. Recently, Suzumura pointed out the limitation of this method for determination of TP in natural waters. He compared wet persulfate digestion with high temperature combustion on sediment, plankton and mineral samples. While

Pennsylvania’s Nutrient Trading Program

The Chesapeake Bay and its tidal waters are listed as impaired under the Clean Water Act (CWA) due to high amounts of nitrogen, phosphorous, and sediment, which in excess can create algae blooms that consume oxygen vital to fish and shellfish, block sunlight for underwater Bay vegetation, and smother bottom dwelling aquatic life. These nutrients and sediments enter the water from agricultural operations, storm water runoff, wastewater facilities, air pollution and other sources. Under the CWA, jurisdictions that have waterways designated as impaired must create a TMDL, which is essentially a “pollution diet” that identifies the maximum amount of a pollutant the waterway can receive, and still meet United States Environmental Protection Agency (EPA) water quality standards. For more than twenty-five years there have been considerable voluntary efforts by states within the Chesapeake Bay watershed to address the amount of nutrients and sediments entering the Bay, with the goal of removing the Bay from the CWA’s list of impaired waters. However, these efforts did not result in the Bay’s removal from the list, and on December 29, 2010, EPA announced a TMDL for the entire Chesapeake Bay watershed. For the Bay TMDL, EPA required Bay jurisdictions to detail how they would meet their respective nutrient allocations through a Watershed Implementation Plans (WIP). The WIP provides a roadmap for how each Bay jurisdiction, in partnership with federal and local governments, will achieve and maintain the Bay TMDL nitrogen, phosphorous, and sediment allocations necessary to meet Bay water quality standards. Pennsylvania’s WIP includes the Nutrient Credit Trading (NCT) Program.

The Effects of Slash Pile Burning on Soil and Water Macronutrients

Significant effects of slash pile burning on soil chemistry and water quality were observed in forested sites in the eastern Sierra Nevada Mountains of Nevada. Slash piles in upland and meadow sites were instrumented postburn with ceramic cup lysimeters, runoff collectors, and resin stakes (Plant Root Simulator™ probes) along transects from pile centers to unburned areas. Ash and soil samples also were collected along these transects. The pH and concentrations of most nutrients in the soil were highest in the centers of the piles. Larger piles had lower levels of total carbon and total nitrogen in the pile centers (indicative of high burn temperatures and volatilization) compared with smaller piles. There also were differences between meadow and non-meadow systems including higher soil NO3− and lower SO42− amounts in the meadow areas. Soil solution data indicated that peak concentrations exceeded US Environmental Protection Agency water quality standards for both NO2−-N and NO3−-N at all three sites and were 2.5 to 3 times the standards in two sites. Runoff solution peak concentrations also exceeded the standards but only in the meadow site.

Characterization and treatment of water used for human consumption from six sources located in the Cameron/Tuba City abandoned uranium mining area

The purpose of this research was the characterization and improvement of the quality of water used for human consumption of unregulated/regulated water sources located in the Cameron/Tuba City abandoned uranium mining area (NE Arizona, western edge of the Navajo Nation). Samples were collected at six water sources which included regulated sources: Wind Mill (Tank 3T-538), Badger Springs and Paddock Well as well as unregulated sources: Willy Spring, Water Wall and Water Hole. Samples taken from Wind Mill, Water Wall and Water Hole were characterized with high turbidity and color as well as high level of manganese, iron and nickel and elevated value of molybdenum. High level of iron was also found in Badger Spring, Willy Spring, and Paddock Well. These three water sources were also characterized with elevated values of fluoride and vanadium. Significant amounts of zinc were found in Water Wall and Water Hole samples. Water Wall sample was also characterized with high level of CrVI. Compared to primary or secondary Navajo Nation Environmental Protection Agency (NNEPA) water quality standard the highest enrichment was found for turbidity (50.000 times), color (up to 1.796 times) and manganese (71 times), CrVI (17.5 times), iron (7.4 times) and arsenic (5.2 times). Activities of 226Ra and 238U in water samples were still in agreement with the maximum contaminant levels. In order to comply with NNEPA water quality standard water samples were subjected to electrochemical treatment. This method was selected due to its high removal efficiency for heavy metals and uranium, lower settlement time, production of smaller volume of waste mud and higher stability of waste mud compared to physico-chemical treatment. Following the treatment, concentrations of heavy metals and activities of radionuclides in all samples were significantly lower compared to NNEPA or WHO regulated values. The maximum removal efficiencies for color, turbidity, arsenic, manganese, molybdenum and nickel were 100.0%. Maximum removal percentage of Cu, F−, V, Zn, 137Cs, 226Ra, 232Th, 238U were as follows: 98.0%; 82.7%; 99.9%; 95.6%; 75.0%; 76.9%; 80.0% and 99.2%. From the results presented it could be concluded that electrochemical treatment is a suitable approach for the purification of drinking water with complex mixture of contaminants, especially those with high turbidity and color.

Sensitivity of early life stages of freshwater mussels (Unionidae) to acute and chronic toxicity of lead, cadmium, and zinc in water

Toxicity of lead, cadmium, or zinc to early life stages of freshwater mussels (fatmucket, Lampsilis siliquoidea; Neosho mucket, L. rafinesqueana) was evaluated in 48-h exposures with mussel larvae (glochidia), in 96-h exposures with newly transformed (5-d-old) and two- or six-month-old juvenile mussels, or in 28-d exposures with two- or four-month-old mussels in reconstituted soft water. The 24-h median effect concentrations (EC50s) for fatmucket glochidia (>299 microg Pb/L, >227 microg Cd/L, 2,685 microg Zn/L) and 96-h EC50s for two- or six-month-old fatmucket (>426 microg Pb/L, 199 microg Cd/L, 1,700 microg Zn/L) were much higher than 96-h EC50s for newly transformed fatmucket (142 and 298 microg Pb/L, 16 microg Cd/L, 151 and 175 microg Zn/L) and Neosho mucket (188 microg Pb/L, 20 microg Cd/L, 145 microg Zn/L). Chronic values for fatmucket were 10 microg Pb/L, 6.0 microg Cd/L, and 63 and 68 microg Zn/L. When mussel data from the present study and the literature were included in updated databases for deriving U.S. Environmental Protection Agency water quality criteria, mussel genus mean acute values were in the lower percentiles of the sensitivity distribution of all freshwater species for Pb (the 26th percentile), Cd (the 15th to 29th percentile), or Zn (the 12th to 21st percentile). The mussel (Lampsilis) genus mean chronic value was the lowest value ever reported for Pb (the 9th percentile) but was near the middle of the sensitivity distribution for Cd (the 61st percentile) or Zn (the 44th percentile). These results indicate that mussels were relatively sensitive to the acute toxicity of these three metals and to the chronic toxicity of Pb, but were moderately sensitive to the chronic toxicity of Cd or Zn compared to other freshwater species.