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Using Microbial Source Tracking To Identify Fecal Contamination Sources in an Embayment in Hempstead Harbor on Long Island, New York

Scientific Investigations Report 2021-5042
Prepared in cooperation with the New York State Department of Environmental Conservation
By: , , , , , and 
https://doi.org/10.3133/sir20215042

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Abstract

The U.S. Geological Survey worked collaboratively with the New York State Department of Environmental Conservation to assess the potential sources of fecal contamination entering Hempstead Harbor, an embayment on the northern shore of Nassau County, Long Island, New York. Water samples are routinely collected by the New York State Department of Environmental Conservation in the harbor and analyzed for fecal coliform bacteria, an indicator of fecal contamination, to determine the need for closure of shellfish beds for harvest and consumption. Fecal coliform and other bacteria are an indicator of the potential presence of pathogenic (disease-causing) bacteria. However, indicator bacteria alone cannot determine the biological or geographical sources of contamination; therefore, microbial source tracking was implemented to determine various biological sources of contamination. In addition, information such as the location, weather and season, surrounding land use, and additional water-quality data (including nutrient and stable isotopes of nitrate analyses) for the location where a sample was collected help determine the geographical source and conveyance of land-based water to the embayment.

Our analysis revealed an abundance of human and canine fecal contamination throughout the Hempstead Harbor landscape and that water from municipal separate storm sewer system conveyances was the most likely transport mechanism of this fecal contamination. Resuspension of bed sediment may contribute to fecal contamination in the harbor, but more targeted analyses are needed to support this finding. There was little evidence of groundwater-contributing fecal bacteria by direct discharge from the subsurface. A classification scheme was developed to convey the degree of fecal contamination to stakeholders and resource managers. Based on this classification scheme, the culvert at Glenwood Road and the outfall and the spillway at Skillman Street were identified as locations that contribute substantial fecal contamination to Hempstead Harbor.

Suggested Citation

Tagliaferri, T.N., Fisher, S.C., Kephart, C.M., Cheung, N., Reed, A.P., and Welk, R.J., 2021, Using microbial source tracking to identify fecal contamination sources in an embayment in Hempstead Harbor on Long Island, New York: U.S. Geological Survey Scientific Investigations Report 2021–5042, 19 p., https://doi.org/10.3133/sir20215042.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Executive Summary
  • Introduction
  • Site Description
  • Approach and Methods
  • Results
  • Classification of Source Sites
  • Summary
  • References Cited
  • Appendix 1
Publication type Report
Publication Subtype USGS Numbered Series
Title Using microbial source tracking to identify fecal contamination sources in an embayment in Hempstead Harbor on Long Island, New York
Series title Scientific Investigations Report
Series number 2021-5042
DOI 10.3133/sir20215042
Year Published 2021
Language English
Publisher U.S Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description Report: vii, 19 p.; Data Release
Country United States
State New York
Other Geospatial Hempstead Harbor, Long Island
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details