back to SoftwareGraduate Student Research Projects:

Matt Habersack-PhD Student

Estimates of fecal bacteria concentrations and die-off rates, fecal production rates, and fecal deposition patterns

The Clean Water Act requires States to identify waterbodies that do not meet their water quality standards, and to then develop Total Maximum Daily Loads (TMDL) for these impaired waters. The TMDL study identifies the sources of pollutants causing the impairment and the maximum pollutant loads the waterbody can receive and still meet water quality standards.

Bacterial impairments are the second leading cause of water quality impairments in the US (USEPA, 2002). Estimates of fecal bacteria concentrations and die-off rates, fecal production rates, and fecal deposition patterns are required to develop bacterial TMDLs. While research exists on agricultural and human bacterial sources, little research exists on wildlife contributions. Consequently, TMDL developers are forced to make questionable assumptions when evaluating bacteria from wildlife. For example, feces production from wildlife has been estimated from domestic animal studies, and some TMDLs have considered wildlife bacterial loadings from a species (white-tailed deer). TMDL developers cannot represent all the significant species that contribute bacteria to water because the data does not exist, or is of unknown quality.

In Virginia, direct deposit of fecal material in streams by wildlife and livestock is believed to be a critical source of bacterial impairments. Semi-aquatic wildlife species, such as beaver, muskrat, raccoon, and waterfowl are believed to be particularly significant and have been included in many TMDLs. Unfortunately, little is known about their fecal production rates and depositional patterns. Current Virginia TMDLs assume that direct deposition is proportional to the amount of time each species spends in water and this is typically estimated using limited data and best professional judgment. Limited research indicates that species like raccoon (Evans, 2002; Giles,1939), otters (Greer, 1955) preferentially defecate at certain locations, making the random distribution of defecation locations within their habitat unlikely as is commonly assumed.

This study will collect needed data on fecal production rates, fecal deposition patterns, and fecal coliform (FC), Escherichia coli (EC), and Enterococcus spp. concentrations in scat from raccoons (Procyon lotor), muskrats (Ondatra zibethicus), and beavers (Castor canadensis). The specific objectives of this research are to:

  1. Quantify fecal production rates for raccoon, muskrat, and beaver,
  2. Quantify Fecal coliform (FC), Escherichia coli (EC), and Enterococcus (ENT) bacteria concentrations in feces,
  3. Quantify fecal bacteria die-off rates in terrestrially and aquatically deposited feces,
  4. Develop a methodology to quantify fecal deposition patterns.
  5. Use the developed fecal bacteria data to redo several TMDLs to determine if the improved wildlife data results in different TMDL reductions.