Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm, contributes dissolved nitrogen into the Muddy Creek watershed. To assess the concentrations of dissolved nitrogen compounds, we sampled waters draining from the Farm as springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. We measured dissolved nitrate (NO­3-) and ammonium (NH4+) using standard colorimetric methods and spectrophotometry with an accuracy of ~0.1 mg/L. Nitrate was the dominant nutrient contaminant, whereas ammonium was often absent in water samples. Nitrate levels were usually \u3c2 mg/L in surface waters. Springs and some tributaries exhibited the largest nitrate values generally ranging from 7.0 to 14.3 mg/L. Ammonium displayed sporadic concentration spikes between 2.0 and 4.3 mg/L. Dissolved nitrogen concentrations responded to rainfall. We saw a general decrease of nitrogen concentration during dry periods, especially in Muddy Creek and an increase in nitrogen concentration under wetter conditions. Springs maintained high nitrogen concentrations regardless of different rainfall conditions. We compared our nitrogen measurements from Meadowbrook Farm to national values. For surface waters, the median nitrate concentration was 2.7 mg/L, lower than the national median (3.8 mg/L), whereas ammonium values were 0.2 mg/L, higher than the national median (0.1 mg/L). In groundwater, we found the median nitrate concentration was 3.9 mg/L, higher than the national median (3.4 mg/L), whereas the median ammonium concentration was 0.05 mg/L, higher than the national median (0.02 mg/L)

Geochemical Characteristics and Storm Dynamics of Surface Waters and Groundwater at Eastern Kentucky University’s Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm raises crops and livestock, contributing dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester and limit nutrient contamination. Before phosphorous sequestration methods can be tested, the geochemistry of surface water and groundwater on the Farm need to be better understood to determine hydrological pathways. We use naturally-occurring, dissolved cations as tracers to identify the contribution of different water sources and interpret storm events. Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for dissolved cations via ICP-OES for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). A V-notch weir was used to quantify volumetric flow for a rain event during tropical storm Cindy. Ca2+ and Mg2+ concentrations (55.5-80.0 mg/L and 21.7-32.5 mg/L, respectively) and lower Na+ and K+ concentrations (9.6-14.8 mg/L and 1.7-18.3 mg/L, respectively) seem to predominantly characterize source groundwater. During Cindy, Ca2+, Mg2+, and Na+ decreased with increasing volumetric flow rate, likely indicating dilution of groundwater. However, K+ exhibited elevated concentrations that spike concurrently with initial discharge peaks and then progressively decrease over the duration of the storm event. We hypothesize that initial K+ increases represent significant overland flow followed by dilution with groundwater and/or continued runoff. If nutrient runoff behavior is similar to potassium, those nutrients should exhibit peak export with initial runoff

Natural Selection For Environmentally Induced Phenotypes In Tadpoles

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137452/1/evo05119.pd

Characterization of groundwater and surface water geochemistry in an agricultural setting at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University (EKU) Meadowbrook Farm raises crops and livestock, which contribute dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester phosphorous and limit nutrient contamination. Before phosphorous sequestration methods can be tested, Farm surface water and groundwater geochemistry must be better understood to determine hydrological pathways for nutrients. We use naturally-occurring dissolved cations, pH, oxidation-reduction potential (ORP), specific conductivity (SC), dissolved oxygen (DO%), total hardness, and alkalinity as chemical tracers to parse the contribution of dissolved ions from different water sources, to recognize different water source chemistries, and to interpret storm events. To measure discharge from a proximal, intermittent stream that drains a representative and critical portion of the Farm, we used an instrumented, V-notch weir to examine storm-water flow during Tropical Storm Cindy (June 22-25, 2017). Water samples taken from springs (groundwater), surface water, and storm water on the Farm were analyzed for various dissolved constituents. Dissolved cations were measured via ICP-OES (ACT Labs) for sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+). pH, ORP, SC, and DO% were determined with YSI and Vernier probes. Alkalinity and total hardness were measured via the bromocresol green - methyl red and the EDTA digital titration methods, respectively. Dissolved ammonium (NH4+), nitrate (NO3-), and phosphate (PO43-) concentrations were determined by colorimetry with a UV-VIS spectrophotometer via the sodium hypochlorite, cadmium reduction, and ascorbic acid methods, respectively. Both groundwater and surface water sources exhibit similar ranges of pH (neutral to basic), ORP (oxidizing), alkalinity, total hardness, DO%, and SC. Source waters generally have high Ca2+ and Mg2+, and low K+, Na+, PO43-, and NH4+ concentrations. This strongly suggests that background chemistries of source groundwater and surface water are controlled by local limestone bedrock dissolution. Groundwater is further characterized by relatively high NO3- concentrations and low temperatures; in contrast, surface waters exhibit higher temperatures and lower NO3- concentrations. During the Cindy event, concentration of Ca2+, Mg2+, and Na+ within baseline source waters decreased with increasing discharge through the weir (Fig. 1), along with SPC, pH, and alkalinity. This behavior represents dilution of Farm groundwater by storm precipitation and subsequent overland flow. However, K+ increased from baseline concentrations, spiking concurrently with increased discharge through the weir, and then progressively decreased in magnitude over the duration of the storm (Fig. 2). These data suggest that K+ was flushed from soil by rain waters. Nutrient concentrations increase with increased discharge indicating transport by surface runoff. For example, PO43- concentrations closely track and are proportional to discharge, which suggests PO43- transport from the surficial soil substrate via flushing by precipitation (Fig. 3). NO3- exhibited nearly identical transport behavior as K+; concentration spikes occur simultaneously with K+ and discharge. However, NO3- levels reached a higher baseline concentration than pre-storm levels. The Cindy event suggests infiltration and retention of NO3- within soil and groundwater during fair weather, initial flushing during the rain event, and then prolonged NO3- release from Farm soil and groundwater. Background concentration of NH4+ is generally 0.0 to 0.2 mg/L. Immediately prior to water flow over the weir during the Cindy event, concentrations were unusually high (~1.7 mg/L). During the first storm pulse, these high concentrations decreased significantly to \u3c0.4 mg/L. Later in the main storm event, NH4+ tracked discharge from the weir and afterward returned to typical background concentrations. This behavior suggests rapid release of NH4+ from soil followed by accumulation within the weir pool and then subsequent flushing during the precipitation event

Nutrient contamination from non-point sources: Dissolved phosphate in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Farms are non-point sources for nutrient contaminants that drain into watersheds and contribute to eutrophication and other environmental problems. Eastern Kentucky University’s Meadowbrook Farm raises both crops and livestock, causing dissolved phosphorus in the form of orthophosphate (PO43-) from fertilizer and animal manure to enter surface and subsurface waters, eventually flowing into Muddy Creek, a tributary of the Kentucky River. We sampled surface water, springs, and water from French drains that emanate from the farm, and also sampled Muddy Creek waters from May through August 2016. Typically, 1 to 2 days after sampling, we colorimetrically measured dissolved orthophosphate concentration using the established ascorbic acid method and a UV-VIS spectrophotometer with general accuracy and precision of ~0.1 mg/L, or ppm. Phosphate values measured from the farm are less than those measured nationally from agricultural lands. The median value of orthophosphate from Farm waters was 0.02 mg/L P-PO4, but nationally the level is ~0.1 mg/L P-PO4; pristine water display 0.010 mg/L P-PO4. Phosphate concentrations are also low when compared to nitrate usually ranging from 0 to 0.2 mg/L P-PO4 with higher concentrations of 0.5 to 2.7 mg/L P-PO4 occurring sporadically. With minor exceptions, we saw little difference in phosphate concentration between different sample sources whether spring water, water from subsurface drains, surface waters flowing over the Farm, or Muddy Creek waters. However, one sub-watershed draining the Farm had increased levels of phosphate on 24 May (2.7 mg/L P-PO4). Overall patterns of phosphate concentration were similar whether sampling during periods with little or no rainfall, or periods following rain events. An exception occurred on 24 June, when overland waters of the same sub-watershed mentioned above had a value of 0.5 mg/L, immediately following a significant rain event

Nutrient contamination from non-point sources: Dissolved nitrate and ammonium in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. We assayed dissolved nutrient levels in surface and subsurface waters of Eastern Kentucky University’s Meadowbrook Farm in order to assess levels of dissolved nutrients leaving its farmland and draining into the Muddy Creek watershed. The Farm raises both crops and livestock so that nutrient sources include fertilizer and manure. We sampled springs, runoff, and subsurface pipe drainage as well as Muddy Creek on six days from May to August 2016 under a variety of weather conditions. Using established, standard colorimetric methods, we measured nitrate (NO3-; cadmium reduction method) and ammonium (NH4+; sodium hypochlorate method) via spectrophotometry with a precision and accuracy of ~0.1 mg/L. Nitrate was the dominant dissolved nitrogen species whereas ammonium was often absent in water samples. Nitrate levels were typically \u3c2 mg/L N- N- NO3 with the largest values between 7.0 and 14.3 mg/L. Springs and some runoff samples had higher nitrate values. Ammonium generally ranged between 0.0 and 0.5 mg/L N- NH4 with concentration spikes between 2.0 and 4.3 mg/L, but from no consistent source. Dissolved nitrogen concentration values responded to rainfall. Generally, nitrate concentrations increased more than ammonium concentrations during wetter periods. Spring samples maintained higher nitrogen concentrations regardless of different rainfall conditions. Lastly, nitrate contamination was significantly lower than composite national values from streams draining agricultural lands, whereas ammonium was about equal to the median national average. Median nitrate concentration was ~1.8 mg/L N- NO3 compared to the national value of ~2.8 mg/L, whereas the value for pristine streams is 0.24 mg/L N- NO3 (Dubrovsky et al., 2010). Median ammonium values from both data sets are ~0.1 mg/L N- NH4; the national value from pristine streams is ~0.025 mg/L N

Dissolved phosphate concentrations in surface water and groundwater at EKU’s Meadowbrook Farm, Madison County, Kentucky

Farms are non-point sources for nutrient contaminants that drain into watersheds and contribute to eutrophication and other environmental problems. EKU’s Meadowbrook Farm raises both crops and livestock, causing dissolved phosphorus in the form of orthophosphate (PO43-) to enter surface and subsurface waters, eventually flowing into the Muddy Creek watershed. We sampled springs, French drains, surface water from the farm, and Muddy Creek waters from May through August 2016. Typically 1 to 2 days after sampling, we measured orthophosphate concentration using the established ascorbic acid method and a UV-VIS spectrophotometer with general accuracy and precision of ~0.1 mg/L, or ppm. Phosphate concentrations are generally low when compared to nitrate usually ranging from 0 to 0.2 mg/L P-PO4 with higher concentrations of 0.5 to 2.7 mg/L P-PO4 occurring sporadically. With minor exceptions, we saw little difference in phosphate concentration between different sample sources whether spring water, water from subsurface drains, surface waters flowing over the Farm, or Muddy Creek waters. For example, one sub-watershed draining the Farm had increased levels of phosphate on 24 May (2.7 mg/L) and on 24 June (0.5 mg/L), immediately following a significant rain event. However, overall patterns of phosphate concentration were similar whether sampling during periods with little or no rainfall, or periods following rain events. In summary, phosphate export from the Farm is apparently low, but more systematic sampling in the future may reveal heretofore unrecognized patterns

Nutrient contamination from non-point sources: Dissolved phosphate in surface and subsurface waters at EKU Meadowbrook Farm, Madison County, Kentucky

Farms are non-point sources for nutrient contaminants that drain into watersheds and contribute to eutrophication and other environmental problems. Eastern Kentucky University’s Meadowbrook Farm raises both crops and livestock, causing dissolved phosphorus in the form of orthophosphate (PO43-) from fertilizer and animal manure to enter surface and subsurface waters, eventually flowing into Muddy Creek, a tributary of the Kentucky River. We sampled surface water, springs, and water from French drains that emanate from the farm, and also sampled Muddy Creek waters from May through August 2016. Typically, 1 to 2 days after sampling, we colorimetrically measured dissolved orthophosphate concentration using the established ascorbic acid method and a UV-VIS spectrophotometer with general accuracy and precision of ~0.1 mg/L, or ppm. Phosphate values measured from the farm are less than those measured nationally from agricultural lands. The median value of orthophosphate from Farm waters was 0.02 mg/L P-PO4, but nationally the level is ~0.1 mg/L P-PO4; pristine water display 0.010 mg/L P-PO4. Phosphate concentrations are also low when compared to nitrate usually ranging from 0 to 0.2 mg/L P-PO4 with higher concentrations of 0.5 to 2.7 mg/L P-PO4 occurring sporadically. With minor exceptions, we saw little difference in phosphate concentration between different sample sources whether spring water, water from subsurface drains, surface waters flowing over the Farm, or Muddy Creek waters. However, one sub-watershed draining the Farm had increased levels of phosphate on 24 May (2.7 mg/L P-PO4). Overall patterns of phosphate concentration were similar whether sampling during periods with little or no rainfall, or periods following rain events. An exception occurred on 24 June, when overland waters of the same sub-watershed mentioned above had a value of 0.5 mg/L, immediately following a significant rain event

Nutrient contamination from an agricultural non-point source and its mitigation: A case study of EKU Meadowbrook Farm, Madison County, Kentucky

Non-point sources are now responsible for most nutrient contamination in surface water and groundwater, leading to eutrophication and decreased water quality. Because of fertilizer use and animal husbandry, agricultural areas are prime sources for nutrient contamination. Consequently, it is advisable to mitigate entry of nutrients into watersheds from agricultural runoff and groundwater flow. Eastern Kentucky University (EKU) Meadowbrook Farm (Madison County, Kentucky) seeks to decrease its export of nutrients to Muddy Creek, which is tributary of the Kentucky River. To demonstrate the efficacy of any sequestration strategies, nutrient export must be measured both before and after sequestration efforts are implemented. Over the past two field seasons, we have investigated the sources and behavior of dissolved nutrients (phosphate, PO43-; ammonium, NH4+; nitrate, NO3-) and other dissolved ions, and their transport via hydrologic pathways at the Farm. Here, we present our findings in three parts: (1) background nutrient concentration in surface water and groundwater during fair-weather times and identification of likely nutrient sources (Borowski et al.); (2) details of cation and nutrient drainage from the Farm during rain events (Buskirk et al.); and (3) quantification of nutrient export from a representative sub-watershed on the Farm during a major rainfall event (Winter et al.). Meadowbrook Farm is a working farm raising crops (mainly corn and soybeans), and rearing dairy and beef cattle and other livestock. Livestock produce manure that is eventually applied to pasture and croplands; supplemental fertilizer is also used. These are the primary sources for excess nutrients that leave the Farm via overland and groundwater flow. We sampled water from several different water sources and measured their nutrient content. Water types include that from drainage tiles, springs (groundwater), and surface water within intermittent streams on the Farm, other adjacent streams, and Muddy Creek. Water samples were passed through a 0.4 mm syringe filter and then preserved at a pH of 2 with sulfuric acid (H2SO4). Nutrient concentration, expressed in terms of phosphorus (P) and nitrogen (N) content, was measured colorimetrically using an UV-VIS spectrophotometer and the ascorbic acid (orthophosphate; P-PO43-), sodium hypochlorite (ammonium, N-NH4+), and cadmium reduction (nitrate, N-NO3-) methods. Nitrate is the nutrient contaminant with highest median concentration (~1.1 mg/L N-NO3) in surface waters; median concentration for ammonium and phosphate are ~0.3 mg/L N-NH4+ and ~0.03 mg/L P-PO43-, respectively. Relative to national data, Farm groundwater is enriched in all nutrients with median concentrations of ~0.04 mg/L N-NH4+, ~7.3 mg/L N-NO3, and ~0.04 mg/L P-PO43-. Enrichment in ammonium is more significant compared to that of nitrate and phosphate. These data provide fair-weather, background estimates for comparison to nutrient export that occur during rain events

Dissolved nitrogen (nitrate and ammonium) in surface and groundwater at EKU Meadowbrook Farm, Madison County, Kentucky

Agricultural activities often contaminate watersheds with excess nutrients, leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm is no exception, and contributes dissolved nitrogen into the Muddy Creek watershed. To assess concentrations of dissolved nitrogen compounds, we sampled waters draining from the farm: springs, runoff, and subsurface pipe drainage as well as Muddy Creek. These water samples were collected on eight days from May through August 2016 under a variety of weather conditions. We measured dissolved nitrate and ammonium using the standard cadmium reduction and sodium hypochlorite methods via colorimetric spectrophotometry with an accuracy and precision ~0.1 mg/L. Nitrate was usually the dominant nitrogen compound, higher ammonium levels occurred only sporadically. Typically, nitrate levels were \u3c2 mg/L with largest values from 7 to 14.3 mg/L. There were few differences in nitrate concentrations in water samples from different sources. However, springs sometimes had higher nitrate concentrations than Muddy Creek and runoff samples. Tributary 6E, draining off-farm areas to the east, consistently had the highest levels of dissolved nitrate relative to other sources. Ammonium values were generally between 0 and 0.5 mg/L. Concentration spikes between 2.0 and 4.3 mg/L occurred, but from no consistent source. We generally did not see consistent patterns of increasing or decreasing nitrate and ammonium concentration with respect to sample type, nor any firm connection with rainfall events. However, in one instance two days after a significant rainfall, higher nitrate and ammonium values were observed in all sample types