Groundwater Flow Direction Research Articles

Hydrogeological Conditions of Groundwater Aquifers/ West Makhul, North Iraq

The lithological description of drilled wells and pumping test analysis used to determine the hydrogeological conditions of the west Makhul area, the main ground water aquifer in the area represented by unconfined aquifer within the sediments of Injana Formation, the hydraulic properties of this aquifer (Transmissivity, Storage coefficient, Hydraulic conductivity) were estimated by pumping test, the flow net of ground water was plotted, it reflected that the ground water flow direction from the northeastern to the southwestern which compatible with the general direction of surface drainage system and general slope

Cluster and multivariate analysis to study the diffuse contamination of emerging per- and polyfluoroalkyl substances (PFAS) in the Veneto Region plain (North-eastern Italy)

In recent years, per- and polyfluoroalkyl substances (PFAS) have emerged as major pollutants of concern. This study considered a real case of superficial and groundwater contamination caused by a set of 15 persistent, carcinogenic, and bioaccumulative compounds. The study area is the Veneto Region floodplain in Italy, where a huge contamination mainly caused by a persistent spill-over from a former chemical factory was discovered in 2013. The contamination path studied in 2013 followed mainly two directions: the first towards east, to the city of Vicenza, and the second following the course of Chiampo and Agno streams, southwards.To identify the major patterns of contamination, a Factor Analysis (PCA) in conjunction with a Cluster Analysis (CA) was performed. The reviewed dataset is composed by PFAS concentration values collected from 2013 to 2021 in groundwater, superficial waters, in natural sources, and in proximity to three industrial discharges, throughout a 3600 km2 area. The CA results were cross-referenced with the water table interpolation, yielding a match between the groundwater flow directions and the observed patterns of the two main plumes. The persistence of pollutants was finally investigated by analyzing distances between the former chemical factory, an industrial wastewater collector which lies along Chiampo and Agno valleys that host residential and industrial areas, and the other sampling points collected in the dataset. The findings confirmed the importance of assessing anthropic background levels of contamination and highlighted the necessity to include the PFAS issue in a national health-based drinking water quality guideline.

Impact of the Hydroelectric Dam on Aquifer Recharge Processes in the Krško Field and the Vrbina Area: Evidence from Hydrogen and Oxygen Isotopes

The impact of the damming of the Sava river for the Brežice hydroelectric power plant on the rise of the groundwater level was studied in the intergranular aquifer of the Krško field and the Vrbina area, Slovenia. The study is based on the application of hydrogen and oxygen isotopes (18O, 2H and 3H). Parameters were determined for precipitation, surface water, and groundwater for periods before and after the filling of the accumulation basin, with the aim of evaluating the groundwater–surface water interaction and to elucidate the impact of the hydroelectric dam on aquifer recharge processes. The results show the proportions of the surface water component in groundwater sampled from four wells at high and low water conditions, separately for the period before and after the filling the accumulation basin. After filling the accumulation basin, the proportion of the Sava river component at high water conditions increased from 60% to 80% in the Brege and Drnovo wells (drinking water resources), from 50% to 80% in the Cerklje well and to almost 100% in the near-river NEK well. Combined with previous studies, the results provide important information about the direction of groundwater flow in the aquifer and improve the conceptual model of the study site.

In‐situ application of colloidal activated carbon for PFAS‐contaminated soil and groundwater: A Swedish case study

AbstractSoil and groundwater contamination by per‐ and polyfluoroalkyl substances (PFAS) has been a significant concern to human health and environmental quality. Remediation of contaminated sites is crucial to prevent plume expansion but can prove challenging due to the persistent nature of PFAS combined with their high aqueous mobility. In this case study, we investigated the potential of colloidal activated carbon (CAC) for soil stabilization at the pilot scale, aiming to entrap PFAS and prevent their leaching from soil into groundwater. Monitoring of the site revealed the presence of two potential sources of PFAS contamination at concentrations up to 23 μg L−1 for ∑11PFAS in groundwater. After CAC application, initial results indicated a 76% reduction of ∑11PFAS and high removal rates for long‐chain PFAS, such as perfluorooctane sulfonic acid and perfluorooctanoic acid. A spike in concentrations was noticed 6 months after injection of CAC, showing a rebound of the plume and a reduction of treatment effectiveness. Based on long‐term monitoring data, the treatment effectiveness for ∑11PFAS dropped to 52%. The rebound of concentrations was attributed to the plume bypass of the barrier due to the presence of high conductivity zones, which likely occurred because of seasonal changes in groundwater flow directions or the CAC application at the site. This demonstrates the need for a detailed and accurate hydrogeological understanding of contaminated sites before designing and applying stabilization techniques, especially at sites with high geologic and hydrologic complexity. The results herein can serve as a guideline for treating similar sites and help avoid potential pitfalls of remedial efforts.

Groundwater conceptual pollution model and related human health hazards, the main dilemma of a desert aquifer near ophiolite complex.

Groundwater is a finite resource in Davarzan region which is located between the ophiolite complex mountain in the north and salty playa at the south. The water samples were analyzed to assess the origin of groundwater pollution and explain links between the disturbed heavy metals composition of the earth's surface and the human health risks. The main heavy metal pollutants in the groundwater are Cr, Fe, As and Pb ions. In general, the groundwater salinity and some elements such as Cr and As are increased along with surface topography and groundwater flow directions from the northern ophiolite highlands recharge area to the adjacent desert discharging zone in the south. Despite the ophiolite complexes being the most enriched in Cr element, the lowest Cr concentration in the groundwater was measured near the ophiolite area, which is in the range of its discharged springs. Based on the groundwater conceptual pollution model, bedrock geochemistry controls the composition of soil and hence that of groundwater. The Cr samples show a direct relation with the EC value indicating that intrusion of salinity from the salt pan is probably another reason for the increased Cr concentration. The results of health risk assessment indicated that the groundwater suffered from significant contamination and if used for long-term without pre-treatment may pose serious health risks to human population via drinking water and irrigation of agricultural fields. This is the first attempt to apply hydrogeological setting along with the source of pollution and its health risk in a desert-ophiolitic area.

Groundwater exploration using drainage pattern and geophysical data: a case study from Wadi Qena, Egypt

In the Wadi Qena region, the digital elevation model (DEM), aeromagnetic, and magnetotelluric data are processed and examined to outline surface water flow patterns, the subsurface structures, demonstrate their effects on the groundwater flow direction, and assess the groundwater aquifer thickness and the relationship between subsurface structures and the inherited surface water flow (drainage pattern). Wadi Qena’s drainage pattern and watershed basins were delineated using satellite digital elevation data in order to accomplish these objectives. The first vertical derivative transformation was used and examined to determine the prevailing northwest-southeast and northeast-southwest structural trends impacting the region. In order to handle aeromagnetic data, it is necessary first to reduce the observed magnetic data such that they correspond to the reduced magnetic pole (RTP). The two-dimensional analytical signal technique was used to discover that the depth of the basement rocks, which in the research region serve as the bedrock of the overlying groundwater aquifer, ranges from 101 to − 1165 m relative to sea level. This information was obtained by measuring the distance from the earth’s surface to the bedrock. To further define the accurate subsurface geological model in the region, the conducted magnetotelluric survey in the area was interpreted using the 1-D inversion technique, and the results were coupled with the existing drill data. The base of the groundwater aquifer was discovered to be between 350 and 410 m deep. Finally, the results are reliable and closely related to earlier geological and geophysical investigations in the studied area.

Investigation of groundwater flow direction using Geospatial technology: A case study in part of Port Harcourt, Rivers State, Nigeria

A geospatial technique was used in some parts of the Port Harcourt metropolis to establish the direction of groundwater movement. This method included the use of twelve carefully selected boreholes and a variety of cutting-edge tools, such as depth meters, handheld GPS, and measuring tape. The static water level in the boreholes and the ground surface elevation in relation to the average sea level of the region were two of the variables that were gathered. High-end software was used to analyze the data in order to create groundwater flow direction maps and 3D visualizations for displaying the whole research region based on the fluctuation in static water levels. This software included Microsoft Excel, ArcGIS 10.4, and ArcScene 10.4. Afterward, the main and minor flow directions were identified. The results showed that groundwater in the area moves from the north to the south, with group 4 having the largest hydraulic gradient and group 1 coming in second. On the other hand, groups 3 and 2 had the lowest hydraulic gradient. The main factors influencing groundwater flow were determined to be gravity and external pressure brought on by pumping. The research region's southern regions are more vulnerable to groundwater pollution, which may result from zones with higher hydraulic heads, according to the flow pattern in the aquifer system. As a result, it is advised that residential boreholes and municipal water wells be located on the study area's northern sides, whereas sanitary landfills and garbage sites should only be located in the southwest.

Analysis of the Prairie Dog Creek Alluvial Aquifer in Northwest Kansas

The geosciences department at Fort Hays State University and the Kansas Department of Health and Environment (KDHE) determined the extent of mineral contamination in three aquifers in northwest Kansas. The contaminant results from the Prairie Dog Creek alluvial aquifer were used for this study. Forty wells spanning across the Kansas counties of Phillips, Norton, and Decatur allowed for statistical and spatial examination of the contamination. Groundwater flow direction was determined from elevation data and well water depth records. A correlation between possible contaminant buildup and groundwater altitude was investigated but did not yield a significant correlation. Since there is no overall buildup in any of the contaminants, very localized sources in geology or land use are affecting individual wells. A large part of this study focuses on communicating the importance of clean drinking water.

2D and 3D visualization of aquifer sediments, surface water seepage and groundwater flow using DC-resistivity, DC-IP, and SP methods, West El-Minia, Egypt

In this study, the SP, DC-Resistivity and DC-TDIP methods were used and included 21 sites for determining the groundwater conditions and visualizing the aquifer sediments, surface water seepage, and groundwater flow in 2D and 3D. The results indicated the occurrence of Quaternary and Tertiary deposits, as well as shallow aquifer of Eocene fractured limestone and Quaternary deposits. The resistivity, chargeability and SP values were compared with each other and 2D and 3D visualization models were designed for these values to understand the sediment distribution and its geological and hydrogeological implications. High to medium, low and very low chargeability values indicated the compact sediments with high shale content, water-bearing layers and freshwater zones and dry sediments, respectively, and varied with the water amount, salinity and effective porosity. Low to very low values of SP indicated the occurrence and high accumulation of groundwater and an increase in shale, permeability and groundwater flow and source, and possibly salinity. The results showed that the resistivity, chargeability and SP values had an important role in separating the dry and saturated sediments and defining the fault zone, determining the source of surface water seepage, classifying the depths of high, medium and low groundwater accumulation and flow and permeability. The IP depended highly on the water amount and shale content and it was interesting in groundwater exploration with resistivity and in differentiating between groundwater and clays. The SP assisted in delineating the surface water seepage and groundwater source and flow direction, and predicting the sediments permeability.

Case analysis on the characteristics of the landcreep area: focusing on Seo-myeon in Suncheon, South Korea

This study was conducted to prevent landcreep damages by examining various features such as geology, topography, and physical characteristics. The first landcreep occurred in Seo-myeon in Suncheon, South Korea, in 2000. The second occurred in 2020, the damaged surface area of the second event was approximately 21.7 times that of the first, and it was discovered that landcreep in Sunchoen was contributed to forest road construction. The study area was a typical landcreep area caused by weathered rocks, and this area belonged to a type of convex terrain ground form. As a result of analyzing the landslide hazard grade, the landcreep is found to be different from general landslides because it includes most areas of landslide hazard grade 3–5 and out of the grade. Results show that the landcreep has proceeded in the directions of S15°E, S20°E, S25°E, and S30°E, which is consistent with the direction following the flow direction of groundwater determined using the electrical resistivity survey method.

Identifying groundwater recharge and discharge zones using geostatistical simulation of hydraulic head and its derivatives

Identifying groundwater flow directions and the locations of recharge and discharge areas is critical for effective groundwater management. Groundwater flow directions, the concavity and the locations of extrema (i.e., minima and maxima) can be assessed using the first and second derivatives of the hydraulic head surface. We developed a geostatistical method to jointly simulate hydraulic head and its first and second derivatives using sequential Gaussian simulation. The derivative values were used to identify regional groundwater flow directions, and the second derivative test was used to probabilistically map the concavity and the locations of extrema in the hydraulic head surface. By comparing the mapped concavity and extrema to known features, it was possible to attribute areas of recharge and discharge to physical features of the system, such as rivers, lakes and geological outcrops. This was applied to Triassic aquifers in the Galilee Basin (Queensland, Australia) to delineate the likely recharge and discharge areas. This provided an objective assessment of likely recharge and discharge zones and their uncertainty, which is an important addition to a region where the hydrogeology has been the subject of much conjecture.

Thermo-hydraulic analysis in geothermal energy walls

A ground source heat pump (GSHP) system provides efficient space heating and cooling and thus is regarded as a contributor to achieve net-zero emissions targets. This study focuses on an economical type of GSHP system – energy walls where earth retaining walls are equipped with pipes to act as geothermal heat exchangers in addition to being geotechnical structures. A detailed numerical investigation is performed to study the long-term heat exchange mechanism between the walls and the surrounding ground. The work highlights the significance of the existence and magnitude of groundwater flow on the temperature distribution of the ground and the thermal performance of energy walls. Compared to the case when there is no subsurface flow, the energy retaining wall can offer up to a 6 % better coefficient of performance (COP) or provide up to 1.3 times higher thermal yield for relatively slow groundwater flow velocities of 0.013 m/d. The COP can improve up to 93 % and thermal yield up to 23 times for high velocities of 2 m/d, even in extremely cooling-dominant thermal demand cases. The study also shows that the ground thermal conductivity plays a crucial role on performance when groundwater flow is minimal, however, as the convective heat transfer resulting from the groundwater flow becomes more dominant, the influence of thermal conductivity gradually diminishes. It is also found that the absorber pipe flow rate has a rather small effect on the system thermal performance, of less than a 10 % COP difference in all studied cases. This suggests that obtaining reliable hydrogeological information specifically on the groundwater flow velocity and direction are crucial for accurate predictions and optimal design for energy retaining walls and large scale GSHP installations. The insights from this study can improve the design and enhance the uptake of retaining walls for efficient heating and cooling of above/underground spaces - critical components in achieving a clean energy future.

Detection of groundwater sources in Lembor village using geoelectrical resistivity method schlumberger configuration

Drought is one of the problems faced by the people of Lembor Village, Lamongan Regency, this problem will be slightly resolved if the area has reserves of groundwater sources. Therefore, this study aims to determine the existence of potential groundwater sources around Lembor Village. The method used is the geoelectrical resistivity method schlumberger configuration. Data acquisition was carried out for 10 measuring points of Vertical Electrical Sounding (VES) with a track length of 310 meters, and a distance between electrodes of 10 meters. The measurement results are then correlated between VES points to produce a 2-dimensional cross-section. The results showed that the measured resistivity value was between 0.03 Ωm to 81.1 Ωm. The structure of the subsurface layer of the study area is dominated by clay and limestone. The indications for the presence of groundwater are found at a depth between 25 to 35 meters at a track distance of 35 to 45 meters, a track distance of 170 to 180 meters, and a track distance of 270 to 280 meters with resistivity values between 0.03 Ωm to 0.32 Ωm. The indications of the presence of groundwater sources need to be investigated in a wider area, to determine the distribution and direction of groundwater flow.

Hydrogeological model for underground oil storage in rock caverns

For underground engineering, hydrogeological conditions of the engineering site are usually complicated, and a fine hydrogeological model is the basis for the accurate analysis of groundwater flow fields. A 3D fine hydrogeological modeling method applicable to large underground engineering was proposed in this study, which was mainly composed of data preprocessing, initial model establishment and model calibration. The modeling method adequately considers the complexity of geometric parameters and the non-uniformity of the spatial distribution of physical parameters in the geological zone. The boundaries of the model were determined based on independent hydrogeological units. The hydrogeological model is calibrated based on the monitoring data and supplementary investigation information. The 3D fine hydrogeological modeling method has been successfully applied to a large underground water-sealed oil storage engineering under construction. The groundwater level, water inflow and flow directions in four typical construction stages were used as the calibration information. Based on the fine hydrogeological model, the flow analysis was conducted to assess the containment properties of the oil storage caverns during operation. The feedback analyses of the buried depth of underground engineering and the permeability reduction ratio of the grouted zone of caverns were carried out. Through flow analyses, the complex geological conditions had obvious influence on the groundwater flow field, and the hydraulic connection between the oil storage and the river boundaries was obtained. The permeability reduction ratio of the grouted zone of caverns in this engineering was from 18% to 45%. The analysis results showed that the oil storages met the requirements of containment properties during operation. The 3D fine hydrogeological model is helpful to accurately analyze the groundwater flow field for underground engineering, and can provide scientific guidance to the design, construction and operation of underground water-sealed oil storage engineering.

Groundwater Heat Pump assessment operation in three cities of south-central Chile: An approach based on aquifer characterization and analytical calculations of Thermal Affectation Zone

The aim of this work is the Groundwater Heat Pump (GWHP) assessment in three cities in south central Chile (Talca, Temuco, and Osorno), considering the hydraulic parameters of the aquifer, its temperature, and the Thermal Affectation Zone (TAZ) generated around the reinjection well due to the reinjected water flow, and temperature difference, due to thermal recovery.According to the hydraulic characterization, the conditions are more favorable in the city of Talca, where the hydraulic conductivity is medium to high. On the other hand, in the cities of Temuco and Osorno, the hydraulic conductivity is low or very low, except in some domains of river belts, where the hydraulic conductivity is medium to high. In all cities, the temperature of the aquifer is very good for heating and cooling. In particular, in Talca downtown there is a positive thermal anomaly that improves the GWHP performance for heating purposes.In each city, the extension of the TAZ was calculated for a reinjection rate of 5 [L/s], and a thermal recovery of 3 [°C] (heating). In each city, the TAZ was calculated for the hydraulic conductivity values corresponding to the percentiles 25, 50, and 75. The hydraulic gradient is fixed for each city. The heating time increases from north to south (Talca, Temuco and Osorno) due to the climate. In all cities and in all cases, temperature dispersion due to groundwater flow is moderate to slight and concentrated around the reinjection well. The largest extension of TAZ in the direction of groundwater flow is calculated in Talca, reaching approximately 30 m. On the other hand, the greatest reach of TAZ in the opposite direction to the groundwater flow is calculated in Osorno, reaching approximately 20 m. The effect of varying injection rates (3, 5 and 10 L/s) does not significantly affect the distance range of TAZ, yet affects the concentration of TAZ around the reinjection well.

Groundwater quality evaluation based on water quality indices (WQI) using GIS: Maadher plain of Hodna, Northern Algeria.

In a semi-arid region of Maadher, central Hodna (Algeria), groundwater is the main source for agricultural and domestic purposes. Anthropogenic activities and the presence of climate change's effects have a significant impact on the region's groundwater quality. This study's goals were to use water quality indices to evaluate the groundwater's quality and its suitability for drinking and irrigation, as well as to identify contaminated wells using a geographic information system (GIS) and the spatial interpolation techniques of ordinary kriging and inverse distance weighting (IDW). The results reveal that all water samples exceeded the World Health Organization's standards for nitrate ions and had alarming concentrations of calcium, chlorine, and sulfate (WHO). According to Piper's diagram, the groundwater hydrochemical facies is composed of the elements sulfate-chloride-nitrate-calcium (SO42--Cl-NO3--Ca2+ water type). The majority of samples fall into the poor water category, slightly more than 10% fall into the very poor water category, and less than 10% fall into the good to the excellent quality category, per the water quality indices, which classify samples in a similar manner. According to irrigation water indices, every sample is suitable for irrigation. Depending on the direction of groundwater flow, the spatial distributions of Ca2+, Na+, Mg2+, SO42-, and Cl- show that their concentrations are high north of the area and relatively low south of Maadher village (Fig.3). Nitrate concentrations are high in the majority of samples, particularly those close to the Bousaada wadi. In most samples, particularly those close to the Bousaada wadi, nitrate levels are high. Various water quality models were described, and GIS spatial distribution maps were created using standard kriging and inverse distance weighting (IDW) techniques through selected semi-variograms predicted against measurements. To determine the origin of mineralization and the chemical processes that take place in the aquifer-which include the precipitation and dissolution of dolomite, calcite, aragonite, gypsum, anhydrite, and halite-the groundwater saturation index was calculated.

Deep Groundwater Flow Patterns Induced by Mine Water Injection Activity

Mine water injection into deep formations is one of the effective approaches for reducing the drainage from coal mines in the arid and semi-arid region of the Ordos basin, China. Many coal mines are attempting to execute the related projects. Under the influence of groundwater protection, the understanding of regional groundwater flow is becoming highly important to the mine water monitoring, whereas quite few academic research teams focus on the deep groundwater flow pattern by mine water injection. This paper reveals the spatial distribution of Liujiagou Formation that is in positive correlation with the terrain, and its local thickness is influenced by the dominant W-E and NE-SW directions of geological structures. Only a part of sandstone rocks consists of aquifers, the rest 61.9% of relatively dry rock provide the enhanced storage space and partial mudstone aquicludes decrease the possibility of the vertical leakage for mine water. The dynamic storage capacity is evaluated at 2.36 Mm3 per 1 km2 and over 25.10 billion m3 in this study area. Two hydrogeologic cross-sections of basin-scale identify the W-E and N-S regional groundwater flow directions, with the lower Yellow River catchment becoming the discharged region. The hierarchically and steadily nested flow systems containing coal mining claims are influenced by coal mining activity. The groundwater depression cone in a shallow coal measure aquifer is caused by mine water drainage whereas the groundwater mound in Liujiagou Formation is generated by mine water injection activity. The numerical simulation revealed that the groundwater head rebound is slightly decreased and will not recover to its initial baseline within 500 years due to its low porosity and permeability. This study elucidates the deep groundwater flow patterns induced by mine water injection and provides a practical methodology for the management and pollution monitoring of mine water injection activity.

Leachate delineation and aquifer vulnerability assessment using geo-electric imaging in a major dumpsite around Calabar Flank, Southern Nigeria.

A near-surface resistivity investigation was undertaken to investigate soil contamination and aquifer vulnerability due to leachate percolation in a major dumpsite in Calabar. The study was undertaken using 2-D electrical resistivity tomography (ERT) and vertical electrical sounding. Ten traverse lines were created within and outside the dumpsite and geo-electric measurement was conducted using dipole-dipole and Schlumberger electrode configurations. Interpretation of the measured data was carried out using DIPROWIN and WinResist program. 2-D resistivity structures were produced, showing four resistivity layers. Conductive layers with a resistivity of less than 14Ωm were delineated as leachate infiltrated and soil-contaminated zones. The study has shown that leachate has spread across all the survey lines except the two control stations outside the dumpsite. The investigation has further revealed that leachate has percolated the subsurface up to 25m in the area. Subsequently, twenty vertical electrical soundings were carried out to evaluate aquifer protective capacity/vulnerability in the area. The interpretation shows the area is underlain by four to five geo-electric layers. Total longitudinal conductance values were calculated. Two VES points (14 and 19), representing 10% of the sounding points, showed a weak protective capacity rating; eight VES points (1, 7, 9, 11, 12, 13, and 18), representing 35% of the soundings, showed a moderate protective capacity rating; ten VES points (2, 3, 4, 5, 6, 8, 10, 15, 16, 17, and 20), representing 55% of the total soundings, showed a good protective capacity rating. Three (3) hand-dug wells were sampled with the view to obtaining the groundwater and leachate flow direction within the dump vicinity. An electric water level recorder was used to determine the static water level (SWL) of the three wells, and the leachate flow direction was determined to be north-easterly.

An integrated approach for an impact assessment of the tank water and groundwater quality in Coimbatore region of South India: implication from anthropogenic activities.

Groundwater in the Coimbatore region is very much essential for irrigation and human beings' day-to-day life activities. This research focuses on the impact of anthropogenic activities on the surface water quality of fourtanks in Coimbatore city and its influences on disturbing the groundwater quality as well. Water quality is degrading as a result of encroachment and other anthropogenic activities. The disposal of municipal garbage and waste from other enterprises into the nearby tank degrades the quality of the water in the tanks. This pollutant-concentrated surface water, together with the leech organism, may percolate via the pore spaces between soil particles, where it will interact with groundwater. The quality of groundwater will be impacted as a result of this interaction. As a result, water quality metrics for both surface and groundwater have been assessed in this study, and spatial interpolation was performed using ArcGIS. The map of the spatial distribution of water quality was produced using ArcGIS. This spatially interpolated water quality map helped researchers understand how the quality of surface and groundwater changed over time. Visual MODFLOW and MT3D were used to simulate the groundwater flow. The MODFLOW program is used to simulate the direction of groundwater flow based on groundwater level and rainfall data. The output of MT3D allowed for accurate calculation of the pollutant movement's amount and direction. In this study, chloride was used as the pollutant transport parameter. A semi-structured interview has been done in the study region to find out more about the availability of drinking water, how waste is disposed of, and how diseases are spread among residents who live close to the tanks.

Spatiotemporal patterns of PFAS in water and crop tissue at a beneficial wastewater reuse site in central Pennsylvania.

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-1 levels). Per- and polyfluoroalkyl substances persist in treated wastewater and are inadvertently introduced into the environment when treated wastewater is reused as an irrigation source. The Pennsylvania State University (PSU) has been spray-irrigating its wastewater at a 2.45 km2 mixed-use agricultural and forested site known as the "Living Filter" since the 1960s. To understand the spatiotemporal patterns of 20 PFAS at the Living Filter, water samples were collected bimonthly from fall 2019 through winter 2021 from the PSU's wastewater effluent and from each of the site's 13 monitoring wells. Crop tissue was collected at the time of harvest to assess PFAS presence in corn silage and tall fescue grown at the study site. Total measured PFAS concentrations in the monitoring wells ranged from nondectable to 155ng L-1 , with concentrations increasing with the direction of groundwater flow. Concentrations within each well exhibited little temporal variability across sampling events, with mixed relationships between PFAS and groundwater elevation observed between wells. Further, >84% of the PFAS present in livestock feed crops were short-chain compounds, with PFAS consumed annually by livestock fed crops harvested from the site estimated to be 2.46-7.67mg animal-1 yr-1 . This research provides insight into the potential impacts of long-term beneficial reuse of treated wastewater on groundwater and crop tissue quality.