Event Title

Phosphorus mobility in the shallow unconfined aquifer at Pineview Reservoir, Utah

Location

Eccles Conference Center

Event Website

http://water.usu.edu

Start Date

1-4-2014 5:20 PM

End Date

1-4-2014 5:40 PM

Description

Phosphorus (P) concentrations in the shallow, unconfined aquifer surrounding Pineview Reservoir (PVR), Utah indicate increased phosphorus transport is occurring in groundwater. Water quality monitoring was conducted to understand groundwater characteristics and P movement. Additionally, N isotopes, B, and Cl/Br ratios were evaluated to determine whether septic system effluent influences groundwater quality. Results indicate that septic system effluents pollute at least two locations in the aquifer surrounding the reservoir. Sediment analyses were conducted on two aquifer sediment types to identify factors important for P mobility. Coarse-grained sandy loam and fine-grained loam sediments were evaluated. Sequential P fractionation experiments revealed that P in both sediments is associated more with calcium minerals than with Fe and Al minerals. Results suggest calcium plays an important role for P retention in these sediments. Fe and Mn oxide concentrations were higher for fine-grained sediments than for coarse-grained sediments. Because of known septic system influence, a set of sorption experiments was completed to determine whether the presence of dissolved organic matter (DOM) influences P sorption and increases P mobility. Reverse osmosis and dialysis were used to concentrate and purify DOM from groundwater. Final DOM was composed of relatively large biomolecules, including sugars and proteins. Results suggest that at the environmentally relevant levels of P and DOM used in experiments, DOM did not create a notable effect on P sorptive behavior. Factors such as saturated sediment sorption sites and the effects of historic septic system loading are more likely the reasons soluble P is present in the shallow unconfined aquifer at PVR.

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Apr 1st, 5:20 PM Apr 1st, 5:40 PM

Phosphorus mobility in the shallow unconfined aquifer at Pineview Reservoir, Utah

Eccles Conference Center

Phosphorus (P) concentrations in the shallow, unconfined aquifer surrounding Pineview Reservoir (PVR), Utah indicate increased phosphorus transport is occurring in groundwater. Water quality monitoring was conducted to understand groundwater characteristics and P movement. Additionally, N isotopes, B, and Cl/Br ratios were evaluated to determine whether septic system effluent influences groundwater quality. Results indicate that septic system effluents pollute at least two locations in the aquifer surrounding the reservoir. Sediment analyses were conducted on two aquifer sediment types to identify factors important for P mobility. Coarse-grained sandy loam and fine-grained loam sediments were evaluated. Sequential P fractionation experiments revealed that P in both sediments is associated more with calcium minerals than with Fe and Al minerals. Results suggest calcium plays an important role for P retention in these sediments. Fe and Mn oxide concentrations were higher for fine-grained sediments than for coarse-grained sediments. Because of known septic system influence, a set of sorption experiments was completed to determine whether the presence of dissolved organic matter (DOM) influences P sorption and increases P mobility. Reverse osmosis and dialysis were used to concentrate and purify DOM from groundwater. Final DOM was composed of relatively large biomolecules, including sugars and proteins. Results suggest that at the environmentally relevant levels of P and DOM used in experiments, DOM did not create a notable effect on P sorptive behavior. Factors such as saturated sediment sorption sites and the effects of historic septic system loading are more likely the reasons soluble P is present in the shallow unconfined aquifer at PVR.

http://digitalcommons.usu.edu/runoff/2014/2014Abstracts/4