| Southeastern Section - 57th Annual Meeting (10–11 April 2008) | |
| Paper No. 31-15 | |
| Presentation Time: 1:30 PM-5:30 PM | ||
THE EFFECT OF LAND USE ON THE NUTRIENTS AND ORGANIC CONTAMINANTS IN THE WATER AND SEDIMENT OF THE RAPPAHANNOCK RIVER | ||
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PINNEY, Jenae E.1, SHAPIRO, Rebecca J.2, KISILA, Ben Odhiambo2, and SHARPLESS, Charles M.1, (1) Chemistry, University of Mary Washington, Jepson Science Center, 1301 College Ave, Fredericksburg, VA 22401, jenae.pinney@gmail.com, (2) Earth and Environmental Sciences, University of Mary Washington, Jepson Science Center, 1301 College Ave, Fredericksburg, VA 22401 The documented degradation of the Chesapeake Bay is a huge environmental concern. Excess nutrients, mainly nitrogen
and phosphorous, from point and nonpoint sources pollute the water, causing
overproduction of algae. Excess algae destroy the ecosystem by preventing
sunlight from reaching aquatic plants. Algal decay also lowers dissolved O2,
further stressing the ecosystem. Organic contaminants, such as pesticides
and constituents of consumer products, may also pollute the bay. The Chesapeake Bay's drastic decrease in oysters is only one of many visible repercussions of
this pollution. This research aims to determine whether
the Rappahannock River is a significant source of pollutants in the Chesapeake Bay. Five sampling locations were chosen to represent different land use
surrounding the river including forest, agriculture, and human
development. Water samples were taken periodically and analyzed for nitrate
and phosphate using spectroscopic analyses. Sediment samples were also
taken from some of the sampling locations and analyzed for phosphate and
organic contaminants using colorimetric analysis and gas chromatography-mass
spectrometry (GC-MS), respectively.
Sampling began in May 2007 and continues on a monthly basis. In the city of Fredericksburg, the concentration of nitrate increased during the summer of 2007. During the same period, samples from sites below the city had lower concentrations of NO3-, presumably due to dilution and uptake by aquatic plants and algae. During the winter of 2007 nutrient levels increased in the agricultural areas due to lowered aquatic primary productivity. Overall, NO3- concentrations have not been at harmful levels during this short sampling time: the majority of samples have been under 0.8 mg/L NO3-. Phosphate in water has also been low during the sampling period: readings have varied between 2.00 and 20.00 µg P / L. Currently, PO43- concentrations do not appear to follow a spatial trend in the river water. The concentrations in dried sediment were between 20.00 and 40.00 mg P / kg. This was well over 100 times the amount found in water, indicating the important role of sediment in nutrient retention. Preliminary GC-MS analysis of sediment has indicated organic contamination, possibly steroid products, but further analysis is needed to confirm identification. | ||
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Southeastern Section - 57th Annual Meeting (10–11 April 2008)
General Information for this Meeting | ||
| Session No. 31--Booth# 26 Undergraduate Research Session (Posters) II Hilton Charlotte University Place: University Lake Ballroom Suites A, B, C 1:30 PM-5:30 PM, Friday, 11 April 2008 Geological Society of America Abstracts with Programs, Vol. 40, No. 4, p. 75 | ||
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