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Per- and polyfluoroalkyl substances (PFAS) are a collective name for thousands of synthetic compounds produced to enhance consumer and industrial products since the 1940s. They do not easily degrade, and some are known to pose serious ecological and human health concerns at trace concentrations (ng L

During the COVID-19 pandemic, wastewater surveillance was leveraged as a powerful tool for monitoring community-scale health. Further, the well-known persistence of some pharmaceuticals through wastewater treatment plants spurred concerns that increased usage of pharmaceuticals during the pandemic would increase the concentrations in wastewater treatment plant effluent. We collected weekly influent and effluent samples from May 2020 through May 2021 from two wastewater treatment plants in central Pennsylvania, the Penn State Water Reclamation Facility and the University Area Joint Authority, that provide effluent for beneficial reuse, including for irrigation. Samples were analyzed for severe acute respiratory syndrome coronavirus 2 (influent only), two over-the-counter medicines (acetaminophen and naproxen), five antibiotics (ampicillin, doxycycline, ofloxacin, sulfamethoxazole, and trimethoprim), two therapeutic agents (remdesivir and dexamethasone), and hydroxychloroquine. Although there were no correlations between pharmaceutical and virus concentration, remdesivir detection occurred when the number of hospitalized patients with COVID-19 increased, and dexamethasone detection co-occurred with the presence of patients with COVID-19 on ventilators. Additionally, Penn State decision-making regarding instruction modes explained the temporal variation of influent pharmaceutical concentrations, with detection occurring primarily when students were on campus. Risk quotients calculated for pharmaceuticals with known effective and lethal concentrations at which 50% of a population is affected for fish, daphnia, and algae were generally low in the effluent; however, some acute risks from sulfamethoxazole were high when students returned to campus. Remdesivir and dexamethasone persisted through the wastewater treatment plants, thereby introducing novel pharmaceuticals directly to soils and surface water. These results highlight connections between human health and water quality and further demonstrate the broad utility of wastewater surveillance.

As analytical capabilities in the early 2000s began to enable the detection of chemicals in environmental media at increasingly small concentrations, chemicals with the potential to cause adverse human and ecosystem health effects began to be found nearly ubiquitously worldwide. The types of chemicals that were targeted for analysis included natural and synthetic hormones, human and veterinary pharmaceuticals, chemicals in personal care products, novel pesticides, nanoparticles, microplastics, and other chemicals of natural and synthetic origin. The impacts of these chemicals on environmental and human health in many cases remain unknown. Collectively, these chemicals became known as "emerging contaminants" or "contaminants of emerging concern". Much progress has been made toward understanding the sources of these contaminants in the environment, the processes that control their fate and transport once they are released into the environment, and the ability of technology and/or best management practices to mitigate their occurrence. As the Journal of Environmental Quality (JEQ) celebrates its 50th anniversary, we sought to understand how publications in the journal have made impactful contributions in the research area of emerging contaminants. Here, we present the trajectory of publications in JEQ that have shaped knowledge in this field, highlight the importance of these contributions, and conclude with opportunities for JEQ to continue attracting high-quality emerging contaminants research. This article is protected by copyright. All rights reserved.

HighlightsThree crop scenarios for eight dairy farm types were simulated using the Integrated Farm System Model.Cover cropping and interseeding each significantly reduced runoff losses, compared to the baseline, for most farm types.Interseeding averaged greater reductions in N, P, and sediment losses than cover cropping.Increases in average annual production costs were Abstract. Intensive agricultural activities are known to increase nutrient and sediment losses, leading to degraded water quality in receiving water bodies. In the Chesapeake Bay watershed, animal operations must reduce farm-level nutrient and sediment losses to meet federally mandated load reduction goals. This work investigated the potential water quality benefits and economic impacts of adopting post-harvest cover cropping or interseeded cover cropping on eight dairy farms representative of common operations in central Pennsylvania. The farms, simulated with the Integrated Farm System Model (IFSM), represented confined, organic, grazing, and Amish farming practices for dairy herds ranging in size from 35 to 150 lactating Holstein cows. Simulations were run for 25 years using observed weather data for Mifflin County, Pennsylvania, and for the dominant agricultural soil series in the county: Hagerstown silt loam. Model output included water balance results, nutrient and sediment loads, and farm-scale economics at an annual scale. Overall, simulation results showed that post-harvest cover cropping reduced N, P, and sediment by 18%, 17%, and 42%, respectively, while interseeding reduced loads by 49%, 41%, and 46%, respectively. Economic impacts of cover cropping and interseeding varied among farm types, but nearly all scenarios resulted in a net loss in profit compared to the baseline. However, annual economic losses were relatively minor: less than $28 ha-1 for cover cropping and $63 ha-1 for interseeding. Results suggest that the benefits of interseeding cover crops are greater for farms with larger portions of land in row crops with less perennial grassland. Interseeding necessitates purchasing additional equipment or custom hiring the seeding operation. These results have implications for cost-share incentive structures aimed at promoting adoption of cover crops and interseeding, especially for confined farms, which may otherwise experience financial losses if these practices are adopted. Keywords: Best management practice, Conservation, Economic evaluation, Erosion, IFSM, Integrated Farm System Model, Nutrient transport, Water quality.

HighlightsWe developed a land suitability framework for sustainable manure utilization based on seven water quality-related environmental vulnerability factors.ArcGIS-based decision-support tools were developed that use readily available data for the U.S.The tools can be adapted to any location in the U.S. for any livestock agricultural system.In a case study, 19.9% of the study area was identified as potentially suitable for manure utilization.2%, 33%, and 44% of the potential areas were highly, moderately, and marginally suitable, respectively.Abstract. Intensive livestock agriculture is a significant source of nutrient pollution that contributes to water quality degradation worldwide. This study presents a land suitability framework and accompanying decision-support tools for sustainable manure management. The developed framework identifies potentially suitable areas for manure application in a user-defined area and further classifies the land as highly suitable, moderately suitable, marginally suitable, and unsuitable using seven environmental vulnerability factors considering landscape biophysical characteristics and proximity to streams. The decision-support tools, built in ArcGIS, were applied in a case study in western Pennsylvania. The ArcGIS toolbox, available from ScholarSphere (https://doi.org/10.26207/99tk-sn24), classified 2% of the case study area as highly suitable for manure application and 21% as unsuitable. Landscape slope and proximity to streams were the dominant vulnerability factors in the case study area. The framework and accompanying tools are transferable across watershed boundaries and can help identify areas where environmentally sustainable animal agriculture can be developed. Keywords: Decision-support tool, Land suitability analysis, Sustainable manure management, Vulnerability analysis.

HighlightsLand management and hydrologic connectivity cause concentrated flow pathways (CFPs) to serve various functions.Pesticide concentrations diminished along flow pathways from row-cropped fields through functional riparian zones.CFPs facilitated pesticide transport into pasture/hay fields from upgradient corn fields.Subsurface transport was likely a more important transport pathway relative to surface runoff for imidacloprid.Abstract. Riparian buffers, which are an important component of watershed management strategies, can effectively mitigate nutrients and pesticides in agricultural runoff. However, concentrated flow pathways (CFPs) can undermine the performance of buffers by allowing contaminant-laden runoff to bypass the mitigation potential offered by the buffer soils and vegetation. To determine the extent to which CFPs increase pesticide transport from agricultural fields to nearby streams, soil samples (0-2 cm depth) were collected along both CFPs and overland flow (OLF) pathways from the field to the stream for nine fields in a Long-Term Agroecosystem Research (LTAR) site in the ridge and valley physiographic region of Pennsylvania. Soil samples were analyzed for atrazine, metolachlor, and imidacloprid, with two dominant patterns emerging. In corn fields, pesticide concentrations were higher in OLF than CFP samples, suggesting that pesticides were mitigated during transport through each corn field. In contrast, hay and pasture fields, which had not been treated with any of the three pesticides of interest, had lower pesticide concentrations in the OLF samples than the CFP samples. Because the CFPs from these fields originated in upgradient unsampled corn fields, these results suggest that the CFPs were a conduit for pesticides applied in the corn fields and were simply flowing through the hay and pasture fields. Similarly, CFPs in riparian buffers and grass pathways located between the row-cropped fields and the stream tended to have lower concentrations than the upland field (OLF-F) but higher concentrations than the buffer OLF, suggesting a potential for increasing overland flow effectiveness in riparian zones by interrupting CFPs leading to the stream. This study highlights the importance of the land management factors and hydrologic connectivity that cause CFPs to serve different functions (mitigation or enhancement) as runoff is conveyed from agricultural fields to a riparian buffer, and ultimately to an adjacent stream. Further, the results highlight the need for design and maintenance solutions addressing the erosion and sediment control issues that commonly undermine agricultural buffer effectiveness. Keywords: Buffers, Concentrated flow, Contaminant fate and transport, Hydrology, Land management, Pesticides, Overland flow, Water quality.

Abstract Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water. Graphic Abstract

Land application of wastewater effluent is beneficial for recharging groundwater aquifers and avoiding direct pollutant discharges to surface waters. However, the fate of non-regulated organic wastewater pollutants, such as pharmaceuticals and personal care products (PPCPs), in such wastewater reuse systems is understudied. Here, a 14-month study (October 2016 through December 2017) was conducted to evaluate the fate and potential risks of seven commonly used PPCPs in a local wastewater treatment plant (WWTP) and from 13 groundwater monitoring wells at a spray-irrigation site where effluent has been spray-irrigated since the early 1980s. Acetaminophen and trimethoprim were the most frequently detected (93%) PPCPs in WWTP influent, while in the effluent, caffeine and trimethoprim were detected most frequently (70%). Wastewater treatment generally reduced concentrations of acetaminophen and caffeine by >88%; however, some compounds had low removal or were present at higher concentrations in the effluent compared with influent (e.g. naproxen, sulfamethoxazole, trimethoprim and ofloxacin). Seasonal trends were observed, with higher PPCP concentrations in the WWTP influent and effluent in the winter. Risk calculations conducted on the wastewater effluent suggest that the risk posed by PPCPs that persisted in the effluent are medium to high to aquatic organisms. Detection frequencies of PPCPs were lower in groundwater samples compared to the effluent, with sulfamethoxazole (40%) and caffeine (32%) as the most frequently detected compounds. Similarly, average concentrations of PPCPs in groundwater were found to be nearly two orders of magnitude lower than concentrations in the effluent. Minimal seasonal influence was observed for groundwater samples. Human health risk assessments indicate that concentrations in groundwater, which is used as a drinking water source, appear to pose minimal risk.

Per- and polyfluoroalkyl substances (PFAS) are a collective name for a growing range of synthetic compounds produced to enhance both consumer and industrial products since the 1940s. Due to their chemical composition, PFAS do not easily degrade and can accumulate within humans and the environment. As water quality detection technologies advance, PFAS are being classified as emerging contaminants because of the risks they pose to human health when present at sufficiently high levels in drinking water and crops. Because PFAS persist in treated wastewater, reusing treated wastewater as an irrigation source can introduce PFAS into agricultural fields. The Pennsylvania State University has been spray-irrigating its treated wastewater at a site known as the “Living Filter” since the 1960s. The site contains ~250 ha of agricultural fields and 13 monitoring wells. Water samples were collected from October 2019 to December 2020 from the wastewater influent and effluent, and from each of the groundwater monitoring wells and analyzed for 20 PFAS compounds. Additionally, crop residue samples were collected from irrigated and non-irrigated areas to assess PFAS build-up in corn silage and fescue resulting from PFAS in the irrigated water. Overall, data suggest that wastewater irrigation has resulted in detectable PFAS concentrations across the Living Filter, with concentrations generally increasing with the direction of groundwater flow. Concentrations varied little across sampling events but were inversely related to groundwater elevation. Further, PFAS present in the crop tissue suggests that PFAS may enter the food chain once those crops are fed to livestock. Research results provide insight into potential impacts of beneficial reuse of treated wastewater on groundwater and crop tissue quality.

Riparian buffers are an important component of watershed management strategies aimed at improving surface water quality. Under ideal conditions, they are well-documented to effectively mitigate nutrients and pesticides in agricultural runoff. However, previous studies have shown that the performance of vegetated buffers can be undermined by the development of concentrated flow pathways (CFPs) that bypass the vegetation, thereby limiting water quality benefits. To understand the occurrence and potential effects of CFPs on pesticide transport from agricultural fields to nearby streams, soil samples (0-2 cm depth) were collected along surface runoff pathways from the field to the stream for nine sites in a Long-Term Agroecosystem Research (LTAR) site in the ridge and valley physiographic region of Pennsylvania. At each site, samples were collected in areas where sheet flow was likely occurring and in CFPs to identify the potential for CFPs to act as sources or sinks of pesticides along the flow path. Samples were extracted for three pesticides of interest: atrazine, metolachlor, and imidacloprid. Two dominant patterns emerged, with concentrations found to be either mitigated or enhanced in CFPs based on pesticide application to surrounding land use. Sites in the first category were row-cropped fields that received inputs of all three pesticides. Concentrations were highest in the non-concentrated flow areas in the field, suggesting that as pesticides are transported across the row-cropped fields, they are mitigated prior to reaching the stream. In contrast, sites in the second category included hay fields that had not been treated with any of the pesticides of interest. Concentrations were highest in the CFPs, suggesting that CFPs were bringing pesticides into the hay fields from upgradient row-crop fields. The results of this study highlight the importance of the land management factors and hydrologic connectivity that cause CFPs to serve different functions (mitigation or enhancement) as runoff is conveyed from the field, to a buffer, and ultimately to an adjacent stream. Further, the results highlight the need for design and maintenance solutions addressing the erosion and sediment control issues that commonly undermine agricultural buffer effectiveness.

Active ingredients in pharmaceuticals and personal care products (PPCPs) can persist through wastewater treatment plants and be released into the environment where they can inadvertently pose risks to non-target organisms. Emerging contaminants (ECs), including PPCPs, are commonly detected in wastewater effluent. With the increasing beneficial re-use of treated wastewater globally, there is a need to understand how spray-irrigation activities affect the occurrence and persistence of ECs in the environment to which they are introduced. Here, we explore the impacts of wastewater spray-irrigation on nearby ephemeral wetlands (e.g., vernal pools) through the use of grab and Polar Organic Chemical Integrative Sampling (POCIS) techniques. This study sought to determine whether integrative sampling techniques are better suited than traditional grab sampling techniques in assessing the presence and concentrations of ECs in vernal pools by evaluating 34 ECs in six vernal pools in central Pennsylvania. Three pools were impacted by wastewater spray-irrigation activities and three were in a nearby forested area. Results of this study found that POCIS detected a wide range of 25 ECs (log Kow between −2.6 and 9.37) more or, in some cases, equally frequently, relative to grab samples. Additionally, grab samples were found to best capture short-lived elevated inputs of ECs (from irrigation events) while POCIS were found to best capture ECs that were present in vernal pools over a longer period of time (weeks to months). For ECs detected more frequently in grab samples, concentrations were higher compared to time weighted average aqueous concentrations estimated from POCIS. This study advances understanding of the potential impact of wastewater beneficial reuse on vernal pools and informs how best to monitor the presence of ECs in vernal pools using integrative and grab sampling techniques.

Planned beneficial re-use of water has become an increasingly common conservation practice worldwide, sparking questions about the degree of water treatment needed to mitigate negative environmental impacts. Since the early 1980s, as an alternative to surface discharge, the Pennsylvania State University has spray-irrigated all of its treated wastewater effluent via land application onto an environmental setting known as the “Living Filter” site (∼245 ha). The impacts of spray irrigation on nearby ephemeral wetlands, known as vernal pools, were explored. The pools gain water from both natural rainfall and spray-irrigation of the University’s treated wastewater. The occurrence and persistence of estrogens in three vernal pools were quantified by analyzing >137 water samples collected from the pools over an eight-week period coincident with the development period of native amphibian larvae. Additionally, dissolved oxygen, oxidation-reduction potential, water level, water temperature, electrical conductivity, pH, and rainfall data were measured continuously throughout the study period within each pool. Further, the treated wastewater effluent was sampled during each weekly spray-irrigation event. Estrone was detected in nearly 100% of the vernal pool samples, with concentrations up to 6.2 ng L−1. Additionally, 17α-estradiol was not detected in the wastewater effluent, but was present in 52% of the vernal pool samples. 17β-estradiol, estriol, and 17α-ethinylestradiol were detected in fewer than 10% of the vernal pool samples. The findings of this research have important implications for management practices that can help protect these critical habitats.

Elevated hydrogen sulfide (H2S) levels have been observed from open-air dairy manure storages that contain gypsum bedding. Gypsum (calcium sulfate), recycled from construction waste and manufacturing defects, provides a cost-effective bedding alternative for dairy cows. Gypsum bedding is reported to control moisture and bacteria in the stalls and can improve soil structure when land-applied. However, gypsum increases H2S production in the anaerobic environment of deep manure storages, which is released in dangerous concentrations when the manure is agitated. This study was undertaken to quantify and compare the H2S concentrations during agitation of manure storages for three dairy stall management categories: farms that use (1) traditional organic bedding, (2) gypsum bedding, and (3) gypsum bedding followed by a treatment added to the manure storage thought to reduce H2S emissions. Three farms used Vital Breakdown (manufactured by Homestead Nutrition, New Holland, Pa.), and one farm used OK-1000 (Pro Ag Solutions, Hawkins, Tex.). Nineteen agitation events at ten farms were monitored during spring and fall hauling seasons. Portable monitoring instruments recorded H2S concentrations around the perimeter of the manure storages prior to and during agitation. Results show that manure storage agitation at farms that use gypsum bedding produced H2S concentrations that were considered immediately dangerous to life and health (above 100 ppm). Increasing gypsum bedding use significantly increased cumulative H2S concentrations (p < 0.0001). Farms that used Vital Breakdown as an amendment significantly reduced cumulative H2S concentrations when compared to farms not using a manure treatment (p < 0.0001). Lower cumulative H2S concentrations at one farm were attributed to the OK-1000 manure treatment. Keywords: Cow, Dairy, Gas, Gypsum, Hydrogen sulfide, Manure, Safety.

Design irrigation rates for treated municipal wastewater effluent (MWE) are usually determined from nitrogen (N) mass-balances, in which the fraction (f) of the total N in the MWE that is lost to the atmosphere is commonly obtained from US Environmental Protection Agency (USEPA) tabulated (design) values: 0.15–0.25 for secondary-treated effluents and 0.1 for tertiary-treated effluents. In 2011 and 2012, f values from an N balance in a tall fescue (Festuca arundinacea Schreb.) hay field in Central Pennsylvania were quantified and compared to the USEPA design f values. The grass field was spray-irrigated with MWE (C:N ratio = 0.04–0.2; near neutral pH, and 70–87% of the MWE-TN was NO3–N) at a rate of ≤5-cm wk−1. Monthly N balances were calculated from April to September in the surface horizon of a Hagerstown soil. The f values of 0.05, 0.1, and 0.2 seemed appropriate for the months of May and June, August and September, and July, respectively. Positive fnb estimates and the logarithm of measured monthly N removal in the aboveground biomass (kg ha−1) were negatively correlated (R2 = 0.99 for monthly mean air temperatures ≥20 °C and R2 = 0.2 for monthly mean air temperatures

Developing successful mitigation strategies for emerging contaminants can be difficult due to incomplete understanding of factors controlling their fate and transport. A variety of data analysis techniques can be used to assess the fate and transport behavior of pollutants in runoff water. Here, we use concentration-discharge, load-discharge, and coefficient of variation relationships to examine how two methods of dairy manure application (surface broadcast and shallow disk injection) affect the transport dynamics of estrogens, total dissolved phosphorus (TDP), and dissolved organic carbon (DOC). Nine surface runoff events were sampled from Oct 2014–June 2015 from 12 research plots (six with each application method) in Central Pennsylvania after fall application. The plots received inorganic fertilizer for 15 years, but only four manure applications since 2012. Both TDP and DOC exhibited similar transport behavior under both manure application methods that indicate transport-limited control of export, potentially due to legacy sources in soils. However, estrogen loads exhibited dilution responses, a sign of source-limited controls. The strength of the dilution response for estrogens was greater for surface applied manure relative to the injected manure, suggesting that manure application methods can be used to control the mobilization potential of estrogens. Additionally, results suggest the longer-term application history of inorganic fertilizer led to the transport-limited dynamics exhibited by TDP, while the short-term application history of manure caused estrogen transport to be source-limited. Our findings provide insight into how anthropogenic drivers (application type, method, and history) and natural drivers (hydrology, biogeochemistry) are interconnected in agricultural fields, and point to opportunities for protecting downstream water quality.

Over-the-counter and prescription medications are routinely present at detectable levels in surface and groundwater bodies. The presence of these emerging contaminants has raised both environmental and public health concerns, particularly when the water is used for drinking either directly or with additional treatment. However, the frequency of occurrence, range of concentrations, and potential human health risks are not well understood, especially for groundwater supplies. Private wells are often not tested for contaminants regulated by drinking water standards and are even less frequently tested for emerging contaminants. By partnering with the Pennsylvania Master Well Owner Network, water samples were collected from 26 households with private wells in the West Branch of the Susquehanna River basin in central Pennsylvania in winter 2017. All samples were analyzed for six pharmaceuticals (acetaminophen, ampicillin, naproxen, ofloxacin, sulfamethoxazole, and trimethoprim) and one over-the-counter stimulant (caffeine). At least one compound was detected at each site. Ofloxacin and naproxen were the most and least frequently detected compounds, respectively. Concentrations from the groundwater wells were higher than those of nearby surface water samples. However, risk calculations revealed that none of the concentrations measured in groundwater samples posed significant human health risk. A simple, physicochemical-based modeling approach was used to predict pharmaceutical transport from septic absorption field to groundwater and further elucidate variations in detection frequencies. Findings indicate that although septic tanks may act as contaminant sources for groundwater wells, the human health impacts from trace-level pharmaceuticals that may be present are likely minimal.

Occurrence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When surface waters are used as drinking water sources, temporal variability in EOC concentrations can potentially impact drinking water quality and human health. To better understand spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study period (April 2016-June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases: Phase I was a spatially distributed sampling approach within the SRB focusing on seven human pharmaceuticals and Phase II was a temporally intensive sampling regime at a single site focusing on a broader range of EOCs. Concentration-discharge relationships were utilized to classify EOC transport dynamics and understand the extent to which hydrologic and anthropogenic factors, such as surface runoff and wastewater effluent, may contribute to EOC occurrence. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Thiamethoxam, a neonicotinoid insecticide, and caffeine exhibited accretion dynamics during high-flow periods, suggesting higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during high-flow periods. Acetaminophen exhibited near-chemostatic transport dynamics, indicating nonpoint source inputs during high-flow periods. Risk calculations revealed that although EOCs posed medium-to-high risk to aquatic organisms, human health risk through fish consumption was low.

Increasing pressure on water resources is a significant challenge for the 21st century. Over the last decade, water reuse has offered a practical approach to wastewater effluent disposal while supporting agricultural production. Irrigation with wastewater can have negative impacts on the soil environment (e.g. increased salinity, reduced hydraulic conductivity) and these are well documented for soils in arid and semi-arid regions; but little research has been conducted for humid regions. Consequently, to understand the impact of wastewater irrigation on humid region soils, a field study was conducted at “The Living Filter” site (central Pennsylvania), where wastewater effluent has been used for irrigation for 50+ years. The study evaluated the differences in physicochemical soil properties throughout the soil profile (to a depth of 120 cm) at wastewater irrigated sites and non-irrigated sites at different landscape positions (summits and depressions). Results showed that both the sodium adsorption ratio (irrigated: 4.93 ± 1.22; non-irrigated: 0.88 ± 1.03) and salinity (irrigated: 0.32 ± 0.12 dS m−1; non-irrigated: 0.07 ± 0.03 dS m−1) of soil extracts were significantly higher in the irrigated soil profiles compared to the non-irrigated soil profiles (but not with regards to landscape position). There was no observable treatment effect on saturated hydraulic conductivity, Ks, (irrigated: 1.96 cm h−1; non-irrigated: 2.39 cm h−1), but Ks had moderately strong inverse relationships with soil pH (R2 = 0.70) and percent organic carbon (R2 = 0.67). Overall, while salts are accumulating in these soils; our data suggest that long-term irrigation with wastewater has not negatively impacted the hydraulic conductivity of this humid region soil. Ongoing monitoring of soil physicochemical properties and wastewater parameters will be needed to maintain the long-term sustainability of the site.

Delineating hydrologic and pedogenic factors influencing groundwater flow in riparian zones is central in understanding pathways of water and nutrient transport. In this study, we combined two-dimensional time-lapse electrical resistivity imaging (ERI) (depth of investigation approximately 2 m) with hydrometric monitoring to examine hydrological processes in the riparian area of FD-36, a small (0.4 km2 ) agricultural headwater basin in the Valley and Ridge region of east-central Pennsylvania. We selected two contrasting study sites, including a seep with groundwater discharge and an adjacent area lacking such seepage. Both sites were underlain by a fragipan at 0.6 m. We then monitored changes in electrical resistivity, shallow groundwater, and nitrate-N concentrations as a series of storms transitioned the landscape from dry to wet conditions. Time-lapse ERI revealed different resistivity patterns between seep and non-seep areas during the study period. Notably, the seep displayed strong resistivity reductions (∼60%) along a vertically aligned region of the soil profile, which coincided with strong upward hydraulic gradients recorded in a grid of nested piezometers (0.2- and 0.6-m depth). These patterns suggested a hydraulic connection between the seep and the nitrate-rich shallow groundwater system below the fragipan, which enabled groundwater and associated nitrate-N to discharge through the fragipan to the surface. In contrast, time-lapse ERI indicated no such connections in the non-seep area, with infiltrated rainwater presumably perched above the fragipan. Results highlight the value of pairing time-lapse ERI with hydrometric and water quality monitoring to illuminate possible groundwater and nutrient flow pathways to seeps in headwater riparian areas.

A field experiment was conducted from 2005 to 2008 in Fulton County, Western Illinois with biosolids from conventional wastewater treatment applied as corn fertilizer in a series of P rates (0, 163, 325, 488, 650 kg P ha(-1)) along with commercial P fertilizer - triple superphosphate P (TSP) as reference to assess biosolids-P plant availability and potential loss to waterbodies through runoff. Air-dried biosolids and TSP were incorporated into surface soil at end of 2005, and corn (Zea mays) was planted for three consecutive years (2006-2008). Concentrations of soil extractable P except for Mehlich-3 P were always lower in the biosolids than TSP treatments at the same P rates. The soil potentially available P in water extractable P (WEP) and Olsen P derived from biosolids-P estimated by the exponential depletion model was 2-4% and 15-24% of total P in the applied biosolids, respectively. The residence time of biosolids-induced WEP and Olsen P in Midwest soil under annual corn cropping was 5 and 2 years, respectively. Corn tissue analysis showed lower increase in P concentration by biosolids-P than TSP. The elevation rate of soluble reactive P (SRP) concentration in simulated runoff was less by biosolids than TSP. Based on the data in this study, the plant availability and environmental risk of biosolids-P are lower than those of TSP in the Midwest soil, thus use of biosolids as P nutrient for corn would not cause a major impairment to water sources even P applied through biosolids was not completely used by annual crop.

The presence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When these surface water bodies are used as drinking water sources, temporal variability in EOC concentrations can potentially impact drinking water quality and human health. To better understand the spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study (April 2016 – June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases, whereby Phase I was a spatially distributed sampling within the SRB focusing on seven human pharmaceuticals while Phase II was a temporally intensive sampling regime at one site focusing on a broader range of EOCs including human and veterinary pharmaceuticals and a neonicotinoid insecticide. Concentration-discharge (C-Q) relationships were utilized to classify the transport dynamics exhibited by EOCs and understand the extent to which transport pathways such as surface runoff and wastewater effluent discharge may contribute to the presence of EOCs. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Concentrations of thiamethoxam, a neonicotinoid insecticide used in agricultural fields, and caffeine exhibited accretion dynamics in surface water during high flow periods consistent with higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during surface runoff events. Acetaminophen exhibited episodic transport dynamics consistent with nonpoint source inputs during high flow periods.

Over-the-counter and prescription medications are routinely present at detectable levels in surface and groundwater bodies. The presence of these emerging contaminants has raised both environmental and public health concerns, particularly when these water supplies are used as drinking water sources. However, the frequency of occurrence, range of concentrations, and potential health risks are not yet well understood, especially for groundwater supplies. We partnered with the Pennsylvania Master Well Owner Network to collect raw water samples from 26 households with private wells in the West Branch of the Susquehanna River Basin. All samples were analyzed for seven over-the-counter and prescription pharmaceuticals: acetaminophen, ampicillin, caffeine, naproxen, ofloxacin, sulfamethoxazole, and trimethoprim. At least one compound was detected at all sites, with ofloxacin detected in 100% of samples while naproxen was not detected in any samples collected. Samples collected from the groundwater wells were compared to surface water samples collected from the West Branch of the Susquehanna River and concentrations were found to be higher in the groundwater during the same sampling period. A simple modeling approach based on the pharmaceuticals‘ physicochemical parameters (half-life and retardation factor) was employed to provide insight into the differences in frequency of detection for the target pharmaceuticals. Additionally, risk calculations revealed that none of the concentrations observed in the groundwater wells posed any significant human health risk, with risk quotients well below the minimal risk value. However, the risk assessment does not address the potential effect of exposure to mixtures of pharmaceuticals that are likely present in water simultaneously.

The production of hydraulic fracturing fluids (HFFs) in natural gas extraction and their subsequent management results in waste streams highly variable in total dissolved solids (TDS). Because TDS measurement is time-consuming, it is often estimated from electrical conductivity (EC) assuming dissolved solids are predominantly ionic species of low enough concentration to yield a linear TDS-EC relationship: TDS (mg/L) = ke × EC (μS/cm) where ke is a constant of proportionality. HHFs can have TDS levels from 20,000 to over 300,000 mg/L wherein ion-pair formation and non-ionized solutes invalidate a simple TDS-EC relationship. Therefore, the composition and TDS-EC relationship of several fluids from Marcellus gas wells in Pennsylvania were assessed. Below EC of 75,000 μS/cm, TDS (mg/L) can be estimated with little error assuming ke = 0.7. For more concentrated HFFs, a curvilinear relationship (R2 = 0.99) is needed: TDS = 27,078e1.05 × 10−5*EC. For hypersaline HFFs, the use of an EC/TDS meter underestimates TDS by as much as 50%. A single linear relationship is unreliable as a predictor of brine strength and, in turn, potential water quality and soil impacts from accidental releases or the suitability of HFFs for industrial wastewater treatment.

Riparian seeps have been recognized for their contributions to stream flow in headwater catchments, but there is limited data on how seeps affect stream water quality. The objective of this study was to examine the effect of seeps on the variability of stream NO3-N concentrations in FD36 and RS, two agricultural catchments in Pennsylvania. Stream samples were collected at 10-m intervals over reaches of 550 (FD36) and 490 m (RS) on 21 occasions between April 2009 and January 2012. Semi-variogram analysis was used to quantify longitudinal patterns in stream NO3-N concentration. Seep water was collected at 14 sites in FD36 and 7 in RS, but the number of flowing seeps depended on antecedent conditions. Seep NO3-N concentrations were variable (0.1-29.5 mg/l) and were often greater downslope of cropped fields compared to other land uses. During base flow, longitudinal variability in stream NO3-N concentrations increased as the number of flowing seeps increased. The influence of seeps on the variability of stream NO3-N concentrations was less during storm flow compared to the variability of base flow NO3-N concentrations. However, 24 h after a storm in FD36, an increase in the number of flowing seeps and decreasing streamflow resulted in the greatest longitudinal variability in stream NO3-N concentrations recorded. Results indicate seeps are important areas of NO3-N delivery to streams where targeted adoption of mitigation measures may substantially improve stream water quality.

Riparian seepage zones in headwater agricultural watersheds represent important sources of nitrate-nitrogen (NO₃–N) to surface waters, often connecting N-rich groundwater systems to streams. In this study, we examined how NO₃–N concentrations in seep and stream water were affected by NO₃–N processing along seep surface flow paths and by upslope applications of N from fertilizers and manures. The research was conducted in two headwater agricultural watersheds, FD36 (40 ha) and RS (45 ha), which are fed, in part, by a shallow fractured aquifer system possessing high (3–16 mg L⁻¹) NO₃–N concentrations. Data from in-seep monitoring showed that NO₃–N concentrations generally decreased downseep (top to bottom), indicating that most seeps retained or removed a fraction of delivered NO₃–N (16% in FD36 and 1% in RS). Annual mean N applications in upslope fields (as determined by yearly farmer surveys) were highly correlated with seep NO₃–N concentrations in both watersheds (slope: 0.06; R² = 0.79; p < 0.001). Strong positive relationships also existed between seep and stream NO₃–N concentrations in FD36 (slope: 1.01; R² = 0.79; p < 0.001) and in RS (slope: 0.64; R² = 0.80; p < 0.001), further indicating that N applications control NO₃–N concentrations at the watershed scale. Our findings clearly point to NO₃–N leaching from upslope agricultural fields as the primary driver of NO₃–N losses from seeps to streams in these watersheds and therefore suggest that appropriate management strategies (cover crops, limiting fall/winter nutrient applications, decision support tools) be targeted in these zones.

Intensive agricultural activities in southeastern Pennsylvania (PA) are a leading source of nutrient pollution of the Chesapeake Bay. The Chesapeake Bay water quality regulations issued by the United States Environmental Protection Agency in 2010 require reductions of nitrogen, phosphorus, and sediment from agriculture by approximately one quarter by 2025. A dilemma for the state is how to maintain a vibrant agricultural economy while meeting regulatory targets. One strategy that is receiving significant interest is agricultural development in the state outside the Chesapeake Bay watershed. The soils of western PA have relatively low soil test P values and act as the potential nutrient sinks which may provide an opportunity for new animal agriculture there. However, a detailed environmental impact assessment needs to be conducted before these opportunities could be realized. The overall goals of the study are to conduct a geospatial analysis and develop tools to explore the potential for sustainable manure management in western PA. The objectives of the study are to (i) develop a framework for identifying environmentally feasible areas for manure utilization; (ii) develop tools to delineate an area that could accommodate the manure generated from a new livestock farm (i.e., “manureshed”). A pilot study was conducted in three counties in western PA, Armstrong, Indiana, and Westmoreland. In total, 46293 ha (114,392 acres) have been identified as the suitable area for manure utilization. The tools developed to delineate a manureshed can be utilized based on a user-defined location for a potential new animal facility and details about the desired facility size. We expect that the methods and tools developed are transferable to other regions, and that would be suitable for expansion of animal agriculture in a sustainable manner

Stabilization and dewatering methods for wastewater solids determine the concentration and nature of phosphorus (P) in biosolids and in-plant sidestreams recycled to the liquid treatment facility. Because water treatment residuals (WTR) exhibit strong immobilization of soluble P, this study evaluated the impact of co-dewatering WTR and biosolids on the P partitioning during dewatering and the environmental lability of biosolids-P measured by water-extractable P (WEP). Overall, P progressively partitioned into the water-insoluble particulate-bound form in dewatered cake with increasing blending ratio (BR) – defined as the dry mass ratio of WTR to biosolids. The reject water total P (TP) content from dewatering biosolids alone (250 mg L−1) was reduced to 60 mg L−1 for a BR = 1.5. Polymer addition resulted in statistically (α = 0.05) lower reject liquid TP, suggesting the cationic polyelectrolyte contributed to P binding. The WEP of the dewatered cake (∼20% solids) dropped from 2.36 g kg−1 (biosolids only) to ∼0.14 g kg−1 for BR = 1.5, meaning the P in land-applied co-processed cake is less susceptible to solubilization by surface runoff compared to unamended biosolids. Co-dewatering can reduce P in return flows and fix P in the dewatered solids in a form less prone to off-site migration following land application.

summary Shallow groundwater dynamics play a critical role in determining the chemistry and movement of nitrogen (N) in the riparian zone. In this study, we characterized N concentration variability and hydrologic transport pathways in shallow groundwater draining areas of a riparian area with and without emergent groundwater seeps. The study was conducted in FD36, an agricultural headwater catchment in the Ridge and Valley physiographic region of central Pennsylvania, USA. Three seep and adjacent non-seep areas were each instrumented with a field of 40 piezometers installed in a grid pattern (1.5-m spacing) at both 20- and 60-cm depths. Piezometers were monitored seasonally for approximately two years (October 2010–May 2012). Results showed that hydraulic head within seep areas was variable and some regions exhibited upward vertical hydraulic gradients of 0.18–0.27. Non-seep areas were characterized by uniform hydraulic head levels and were relatively hydrostatic. Nitrate-N (NO3-N) concentrations in seep areas were significantly greater than those in the non-seep areas at two of the three study sites. A two-component mixing model using chloride as a conservative tracer indicated that shallow groundwater in seep areas was primarily (53–75%) comprised of water from a shallow fractured aquifer, which had elevated NO3-N concentrations (5.7 mg L � 1 ). Shallow groundwater in non-seep areas, however, was comprised (58–82%) of perched water on top of the fragipan that was likely recharged locally in the riparian zone and had low NO3-N concentrations (0.6 mg L � 1 ). Higher NO3-N concentrations, variable hydraulic head, and groundwater emergence onto the land surface in seep areas provided evidence for preferential flow paths as an important conduit for water and N movement in these areas of the riparian zone. We conclude that the potential for N delivery to the stream in FD36 was much greater from seep areas compared to non-seep areas. Targeted management of seeps should be a priority in efforts to reduce NO3-N levels in riparian zones within headwater agricultural catchments. Published by Elsevier B.V.

Phosphorus (P) indices, originally developed to assess the risk of P export to aquatic systems from agricultural fields receiving inorganic fertilizers and livestock manures, are being used for other P sources with different characteristics and methods of application. This study determined Pennsylvania P index scores for eleven crop fields of Penn State University9s Living Filter system receiving 130 kg P2O5 ha−1 (115 lb P2O5 ac−1) in 2008 via sprinkler irrigation of municipal wastewater effluent. A baseline assessment of P index treated effluent irrigation as surface application of completely soluble P source material with maximum potential of runoff P loss. Three fields located ≤22 m (200 ft) from streams ranked high and very high in P loss rating under baseline assessment. Modified assessments involved changing the application method multiplier and P source coefficient to more accurately reflect the year-round intermittent application of P via sprinkler irrigation. All fields were ranked as having low risk of P export using the modified parameters. Site monitoring data from nearly 50 years of effluent irrigation show no evidence of excess P transport to groundwater or off-site surface water, suggesting that baseline assessment might be overestimating P loss rating of some fields. Results underscore the need to tailor P indexing tools to address the differential risk of P loss for specific P sources and application methods.

Irrigation reuse of municipal effluents conserves freshwater resources and avoids direct nutrient discharges to surface waters. The sustainability of agricultural reuse programs, however, may be challenged by evolving phosphorus (P)-based nutrient management policies. This paper assesses the agricultural and environmental implications of soil P accumulation from effluent irrigation and discusses sustainability under guidelines to control P export in agricultural runoff and drainage. For typical regulatory maximum irrigation rates (5.1 cm wk-1), secondary effluents containing 3–4 mg P L-1 provide ∼90 kg P ha-1 yr-1 and cause soil P enrichment beyond levels needed for optimum crop yields. Applied P potentially falls short of crop needs for advanced wastewater treatment processes with low (

Incorporation of manure slurry under reduced tillage conditions remains a challenge in the northeastern US. New technologies to directly incorporate slurry are available but their agronomic and environmental benefits have generally not been quantified. This study evaluated the effects of five manure slurry application methods on phosphorus (P) loss in runoff (broadcasting with and without incorporation by tillage, shallow disk injection, banded application and aeration, and pressurized injection) and a control (no manure). Research was conducted over a 2 year period in central Pennsylvania on a well-drained Hagerstown silt loam (fine, mixed, semiactive, mesic Typic Hapludalf) under corn (Zea mays L.) production. Approximately 72 h after dairy (Bos Taurus) slurry application (56,000 l ha−1) to 10 × 13 m plots, a single rainfall simulation (68 mm h−1) was conducted in triplicate on 10 × 2 m areas within the plots. Trends in total P losses in runoff (kg ha−1) from plots varied between years and treatments. Aeration yielded lower losses than all other treatments in 2006 and was amongst the lowest in 2007 with losses statistically similar to shallow disk and pressure injection. Remarkably, few differences were apparent in losses of dissolved reactive P between treatments, reflecting high variability in runoff depths. Indeed, variability in runoff depths resulted in some unexpected trends, including high loads from the unamended control and modest loads from the tillage treatment. Results highlight tradeoffs in alternative manure slurry application practices but point to the potential to significantly lower runoff P losses from reduced tillage systems receiving manure slurry.

Widespread implementation of the phosphorus (P) index has focused attention on environmental manure tests that can be used to estimate the relative availability of P in manure to runoff water. This article describes the development and use of a water extractable P (WEP) test to assess the capacity of land‐applied manure to enrich P in runoff water. WEP of surface‐applied manure has been shown to be strongly correlated to dissolved P concentrations in runoff from agricultural soils. WEP tests that have a defined water‐to‐manure‐solids ratio and involve extraction times of 30 to 120 min provide the best prediction of dissolved P in runoff across a wide range of manures. Consistent measurement of manure WEP can be achieved with manure sample storage times of up to 22 days (4°C), acidified extract holding times of 18 days, and solid separation by either centrifugation or paper filtration. Reproducibility of WEP tests is comparable to that of other common manure tests (e.g., total P), as verified by w...

Drinking-water treatment residuals (WTRs) are nonhazardous materials that can be obtained free-of-charge from drinking-water treatment plants to reduce soluble phosphorus (P) concentrations in poorly P sorbing soils. Phosphorus sorption capacities of WTRs can vary 1-2 orders of magnitude, on the basis of short-term equilibration times (up to 7 d), but studies dealing with long-term (weeks to months) P retention by WTRs are lacking. Properties that most affect long-term P sorption capacities are pertinent to the efficacy of WTRs as amendments to stabilize P in soils. This research addressed the long-term (up to 80 d) P sorption/desorption characteristics and kinetics for seven WTRs, including the influence of specific surface area (SSA), porosity, and total C content on the overall magnitude of P sorption by seven WTRs. The data confirm a strong but variable affinity for P by WTRs. Aluminum-based WTRs tended to have higher P sorption capacity than Fe-based WTRs. Phosphorus sorption with time was biphasic in nature for most samples and best fit to a second-order rate model. The P sorption rate dependency was strongly correlated with a hysteretic P desorption, consistent with kinetic limitations on P desorption from micropores. Oxalate-extractable Al + Fe concentrations of the WTRs did not effectively explain long-term (80 d) P sorption capacities of the WTRs. Micropore (CO 2-based) SSAs were greater than BET-N2 SSAs for most WTRs, except those with the lowest (

Isotherms were developed at pH 6.9 for adsorption (ADS) and coprecipitation (CPT) of Cu by hydrous oxides of Fe (HFO) and Al (HAO) to study the role of sorbate/sorbent ratio in metal cation removal. For low sorbate/sorbent conditions, HFO had a higher Cu retention capacity than HAO regardless of contact methodology. For either oxide, CPT was consistently more effective than ADS in removing Cu from solution. At high sorbate/sorbent ratios, surface precipitation dominates and the oxide's net cation retention capacity depends on the nature and solubility of the precipitate formed at the oxide-water interface. X-ray diffraction patterns and isotherms of HAO for both ADS and CPT suggest formation of a solid solution [e.g., CuAl2O4(s)] with dramatically lower solubility than Cu(OH)2(s) precipitated in bulk solution. In contrast, Cu precipitated on the HFO surface exhibited a solubility comparable to the bulk precipitated Cu(OH)2(s). Therefore, at high sorbate/sorbent ratios, HAO has a higher Cu "apparent" sorption capacity than HFO. The relative utility of these oxides as metal scavengers thus depends markedly on sorbate/sorbent conditions. Copyright 1999 Academic Press.

Oxalate (Ox) was used to extract Pb and Zn from industrially contaminated soils. Although Ox effectively releases metals bound by hydrous oxide soil components, it forms insoluble salts with some heavy metals unlike conventional extractants (e.g., EDTA). The insolubility of PbOx(s) (Ksp=2.74 × 10−11) precluded the use of Ox as a single-step extractant even for soils mildly contaminated with Pb. The usefulness of Ox as a Zn extractant, however, depends on the level of soil contamination. A Zn solubility model, based on published equilibrium constants, was developed to assess Ox suitability as a function of system conditions. Precipitation of ZnOx(s) hindered Zn recovery under acidic conditions where formation of soluble oxalato complexes was small. For pH

Oxalate (Ox) was investigated as an extractant for decontaminating two metal-polluted soils, one with elevated total zinc (ZnT = 2700 mg kg-1) from the Palmerton, Pennsylvania smelter site and the other from a grossly contaminated (PbT = 210 000 mg kg-1) automobile battery recycling facility in Indiana. Metal retention within the soils was substantially different as shown by sequential fractionation experiments. High Zn removal (>80%) was achieved with 1.0 M Ox when Zn existed predominantly in non-detrital metal fractions. However, Ox was an unsuitable Pb extractant due to the sparing solubility of PbOx(s). Despite the dramatically higher stability of ZnEDTA2- (log K = 16.5) compared to ZnOx° (log K = 3.4), Ox released more Zn than EDTA from the Palmerton soil because 40% of ZnT was associated with the oxide fraction. Extract analysis indicated that Ox, but nor EDTA, dissolved soil Fe oxides in the 24 hr extraction period. When contaminating metals are associated with soil oxides, Ox may be a superior extractant to powerful chelants like EDTA. It is essential to establish thoroughly metal solution chemistry and fixation behavior within the soil when extractive decontamination is proposed for site remediation.

Hydrous oxides of iron (HFO) and aluminum (HAO) were studied for their ability to reduce Cu (initially 4.3 mg/L) to microgram per liter levels typical of increasingly stringent wastewater discharge limits. Residual soluble Cu was compared following adsorption (ADS), where Cu was contacted with preformed oxide flocs, and coprecipitation (CPT), where Cu was added prior to HFO or HAO precipitation. For the HAO-ADS system, soluble Cu levels were markedly undersaturated with respect to homogeneous precipitation (PPT) of Cu(OH)2(s) over the pH 6−9 range. In contrast, soluble Cu was lowered by HFO-ADS for pH

A geographic information system model was developed to locate monofill construction sites for drinking water treatment residuals. Suitability was defined primarily by a site`s capacity to prevent leaching of constituents of the residual to groundwater. The model considered land use, topography, bedrock geology, soils, and state regulatory criteria. Adsorption experiments were conducted using cadmium as a representative pollutant to assess the ability of the soils to limit treatment residual migration. Applied in southeastern Pennsylvania, the methodology identified only 6.37 sq mi (16.5 km{sup 2}), 2.1 percent of the area screened, as suitable for monofills. The major strength of this model is the quick elimination of parcels that fail to meet regulatory or groundwater protection standards. Because it identifies sites that afford the greatest environmental protection, the model is also a valuable aid in winning public acceptance of disposal facilities.

Co-dewatering of water treatment residuals (WTR) and wastewater biosolids can potentially benefit municipalities by reducing processing equipment and costs. This study investigated dewaterability (using capillary suction time, CST) of combined alum residuals (Al-WTR) and anaerobically digested biosolids at various blending ratios (BR), defined as the mass ratio of WTR to biosolids on a dry solids basis. Without polymer addition, the CST was 160 s for a BR of 0.75 compared with 355 s for the biosolids alone. The optimum polymer dose (OPD), defined as the polymer dose yielding CST of 20 s, was reduced from 20.6 g kg−1 dry solids for the biosolids alone to 16.3 and 12.6 g kg−1 when BR was 0.75 and 1.5, respectively. Precipitated Al hydrous oxides in the WTR likely caused flocculation of the biosolids particles through heterocoagulation or charge neutralization. The solids contents of the blended materials and biosolids at their respective OPDs were not statistically different (α = 0.05) following dewatering by a belt-filter press. We conclude addition of Al-WTR improved biosolids dewaterability and reduced polymer dosage. In practice, the extent of these benefits may be limited by the quantity of WTR produced relative to the amount of wastewater solids generated by a municipality.

In order to evaluate the extent to which sewage treatment plant effluent (STPE) irrigation reduces or eliminates the entrance of endocrine disrupting compounds (EDCs) into groundwater, studies on the fate and transport of selected EDCs in the Penn State spray-irrigation system are on-going. This study reports the variations in the occurrence of 17 s-estradiol (E2), estrone (E1) and 17 a-ethynlestradiol (EE2) in the Penn State STPE during high (>7000 m3/d) and low (approximately 4000 m3/d) flow and at different time periods during the day. Effluent samples were collected throughout the year at times when school was in session (high flow) and also when school was out of session (low flow). The samples collected were cleaned up and concentrated by solid phase extraction followed by detection and quantification using liquid chromatography tandem mass spectrometry. The estrogens, E1, E2 and EE2 concentrations found were 33.2 ng/L (6.1- 235.4); 48.13 (