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Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

Science of the Total Environment

By:
, ,
DOI: 10.1016/j.scitotenv.2011.10.017

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Abstract

Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17β-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations > 1 ng/L. Relatively high concentrations of DIN (> 1000 μg/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R2 = 0.56–0.81) and E2Eq (R2 = 0.39–0.75). Relationships between watershed densities of AFOs and PO4-P were weaker, but were also significant (R2 = 0.27–0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO4-P than streams without WWTP discharges, and PO4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams
Series title:
Science of the Total Environment
DOI:
10.1016/j.scitotenv.2011.10.017
Volume
414
Issue:
1
Year Published:
2012
Language:
English
Publisher:
Elsevier
Contributing office(s):
Leetown Science Center
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
268
Last page:
276
Country:
United States