title: Pathogen reduction co-benefits of nutrient best management practices.
abstract: BACKGROUND
  Many of the practices currently underway to reduce nitrogen, phosphorus, and sediment loads entering the Chesapeake Bay have also been observed to support reduction of disease-causing pathogen loadings. We quantify how implementation of these practices, proposed to meet the nutrient and sediment caps prescribed by the Total Maximum Daily Load (TMDL), could reduce pathogen loadings and provide public health co-benefits within the Chesapeake Bay system.
  
  
  METHODS
  We used published data on the pathogen reduction potential of management practices and baseline fecal coliform loadings estimated as part of prior modeling to estimate the reduction in pathogen loadings to the mainstem Potomac River and Chesapeake Bay attributable to practices implemented as part of the TMDL. We then compare the estimates with the baseline loadings of fecal coliform loadings to estimate the total pathogen reduction potential of the TMDL.
  
  
  RESULTS
  We estimate that the TMDL practices have the potential to decrease disease-causing pathogen loads from all point and non-point sources to the mainstem Potomac River and the entire Chesapeake Bay watershed by 19% and 27%, respectively. These numbers are likely to be underestimates due to data limitations that forced us to omit some practices from analysis.
  
  
  CONCLUSIONS
  Based on known impairments and disease incidence rates, we conclude that efforts to reduce nutrients may create substantial health co-benefits by improving the safety of water-contact recreation and seafood consumption.
authors.affiliation: RTI International , Washington, District of Columbia , United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Richkus
authors.affiliation: Center for Environmental Science, University of Maryland , Solomons, Maryland , United States.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Wainger
authors.affiliation: RTI International , Washington, District of Columbia , United States.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Barber
keywords: Best management practices; Chesapeake Bay; Ecosystem services; Fecal coliform; Nutrients; Pathogens; TMDL; Water quality