Skip to main content
U.S. flag

An official website of the United States government

Suburban groundwater quality as influenced by turfgrass and septic sources, Delmarva Peninsula, USA

January 1, 2015

Suburban land use is expanding in many parts of the United States and there is a need to better understand the potential water-quality impacts of this change. This study characterized groundwater quality in a sandy, water-table aquifer influenced by suburban development and compared the results to known patterns in water chemistry associated with natural, background conditions and agricultural effects. Samples for nutrients, major ions, and isotopes of N and O in NO3 were collected in 2011 beneath turfgrass from 29 shallow wells (median depth 3.7 m) and from 18 deeper wells (median depth 16.9 m) in a long-term suburban development. Nitrate (as N) concentrations in groundwater beneath turfgrass were highly variable (0.02–22.3 mg L−1) with a median of 2.7 mg L−1, which is higher than natural water chemistry (>0.4 mg L−1; Na+–Cl–HCO3 water type), but significantly lower than concentrations beneath a nearby agricultural area (median 16.9 mg L−1; p < .0001). Dissolved Fe concentrations in shallow suburban groundwater, attributed to chelated Fe in turfgrass fertilizers, were significantly higher (p < .005) than concentrations from the agricultural site, although a Ca2+–Mg2+–Cl–NO3 water type was dominant in both areas. A Na+–Cl–NO3 water type indicated a septic-system source for nitrate in deep suburban groundwater (0.06–6.0 mg L−1; median 1.5 mg L−1). Isotopic data indicated denitrification; however, geochemical techniques were more helpful in identifying nitrate sources. Results indicate that suburban expansion into agricultural areas may significantly decrease overall nitrate concentrations in groundwater, but excessive turfgrass fertilization could result in localized contamination.

Publication Year 2015
Title Suburban groundwater quality as influenced by turfgrass and septic sources, Delmarva Peninsula, USA
DOI 10.2134/jeq2014.06.0280
Authors Joshua W. Kasper, Judith M. Denver, Joanna K. York
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Environmental Quality
Index ID 70144686
Record Source USGS Publications Warehouse
USGS Organization Maryland Water Science Center