Dorevitch et al. data coming from Keystone Lake, Oklahoma (U.S. EPA 1983, 1984). None of the support- ing data were collected at rivers. Additionally, European IW recreation research is limited by the use of unique settings (Fewtrell et al. 1992; Lee et al. 1997), limited groups of participants (van Asperen et al. 1998), limited water qual- ity measures (Ferley et al. 1989), and abbrevi- ated reporting of illness rates (Fewtrell et al. 1994). European trials of randomized expo- sure to IWs have been conducted as part of the Epibathe study (European Commission 2010; Wiedenmann et al. 2006). However, the exposure, three head immersions over a 10-min period, is different from actual swim- ming; thus, extrapolating findings to other contexts is difficult. The BEACH Act (2000) mandated that the 1986 criteria be applied to all U.S. marine and Great Lakes CWs, but the mandate was not extended to IWs. This Act also required that the U.S. EPA conduct epidemiologic studies at beaches to develop information for issuing new or revised criteria. As a result, the National Epidemiological and Environmental Assessment of Recreational Water (NEEAR) study (Wade 2006, 2008) has been con- ducted at marine and Great Lakes beaches. To address the BEACH Act requirement that the U.S. EPA develop more timely indi- cators of water quality, the NEEAR study used quantitative polymerase chain reaction (qPCR) tests for FIB that could produce same-day results. In 2006, the U.S. EPA was sued by the Natural Resources Defense Council (NRDC) and others for failing to meet BEACH Act research and regulatory deadlines for recre- ational waters. In August 2008, the U.S. EPA entered into a consent decree (NRDC/EPA 2008), which mandated that new or revised criteria be issued by 15 October 2012. The consent decree required that the U.S. EPA “[e]valuate the applicability of NEEAR Great Lakes data to inland water.” Thus, a policy imperative exists to consider establishing IW AWQC, but the epidemiologic knowledge base for criteria development is very limited. Extending AWQC derived from studies con- ducted at coastal sites to IWs involves major assumptions: a) similar densities of FIB reflect a similar health risk in inland and coastal set- tings, presumably because they reflect a simi- lar risk of exposure to pathogens of similar infectivity and virulence; b) hydrogeochemi- cal differences among inland lakes, rivers, and CWs would be assumed to have nondiffer- ential impacts on the transport and fate of indicators and pathogens; and c) the criteria derived from the studies conducted at sewage- impacted coastal beaches would be assumed to protect against illness in inland settings, where the dominant pollutant sources may be wildlife and/or agricultural animals. 872 To assess these assumptions, and more broadly, the state of the science that could support the application of coastal-derived cri- teria to IWs, a 3-day workshop of 31 national and international experts was convened in February 2009 by the Water Environment Research Foundation (WERF) with support from the U.S. EPA. Workshop participants identified critical knowledge gaps and outlined research needs that could be met by December 2010 (the deadline for completing research that will be reviewed in the development of the 2012 criteria) or between 2010 and 2015 (for consideration in future AWQC). A detailed report of workshop proceedings is available online (Water Environment Research Foundation 2009). In this meeting report the chairs of the working groups and the editor of the WERF report have summarized work- shop highlights and added updates based on subsequent discussions. CWs and IWs: Superficial Similarities General principles of hydrology, microbiology, and public health should apply across all water recreation settings. Surface waters, regardless of matrix and geologic setting, are governed by the same ecologic, hydrologic, and geographic principles. Likewise, ingesting a specific quan- tity of a given viable pathogen in any surface water should produce similar health risks. Consistent with this notion, health risks associ- ated with water recreation have been identified at Great Lakes (U.S. EPA 1984; Wade et al. 2006, 2008) and U.S. marine settings (Colford et al. 2007; U.S. EPA 1983) and with IWs in Europe (Ferley et al. 1989; Wiedenmann et al. 2006). If monitoring of FIB at inland recreational waters was mandated, testing that is currently conducted for other regulatory purposes could, with sufficient resources, be expanded. Thus, at first glance, it seems that recreational criteria derived from CW studies could be applied to and implemented for IW. There are, however, important differences to consider between IWs and CWs. Important Differences between CWs and IWs Several critical differences exist between CWs and IWs, which can be understood primar- ily as a function of the scale of water body of interest. Scale here refers to the volume, sur- face area, related landscape, and the flow (for flowing waters). Scale can influence water- shed interactions, runoff, dilution, currents, wave height, turbulence, resuspension, and source complexity. Differences in pathogen source. The ulti- mate determinants of health risks are thought to be dependent on the dose and virulence of pathogens ingested by recreators, not whether the waters are categorized as coastal or inland. IWs are generally dominated by more rural areas and agricultural land use and are thus more likely to be affected by wildlife and livestock than are coastal watersheds. Warm- blooded animals have the potential to carry a variety of human pathogenic bacteria and protozoa and may pose human health risks (Dorner et al. 2004). For example, Leptospira in the urine of infected wildlife or livestock can contaminate surface waters and infect humans via skin breaks or by ingestion. U.S. outbreaks of leptospirosis have occurred in the context of IW limited- and full-contact recreation (Jackson et al. 1993; Morgan et al. 2002; Yoder et al. 2008). A recent U.S. EPA review identified several recreational outbreaks tentatively linked to wildlife and livestock sources, although definitive confirmations of animal sources have been lacking (U.S. EPA 2009). With limited dilution in inland set- tings, bathers themselves can become sources of fecal pathogens. Sporadic mild illness (Calderon et al. 1991) and, more conclu- sively, numerous outbreaks of severe disease including E. coli 0157:H7 (Bruce et al. 2003; Keene et al. 1994; Yoder et al. 2008) have been linked to other bathers at IWs. hTe importance of sediment in IWs. Small lakes and streams are closely associated with watershed factors such as soils, runoff charac- teristics, shoreline processes, and meteorologi- cal events. Turbulent flow in IWs may lead to resuspension of sediment-associated FIB. Numerous studies have found that E. coli and enterococci can persist and potentially regrow in sediments and soils (Byappanahalli and Fujioka 2004; Byappanahalli et al. 2006; Davies et al. 1995; Desmarais et al. 2002). Regrowth of FIB is suspected to occur at the water/sediment boundary (Wheeler Alm et al. 2003; Yamahara et al. 2009). The effect of sediment resuspension on FIB in IWs could be amplified at the boundary layer, which, compared with CW settings, is larger in rela- tion to the volume of surface water. An area of consensus among workshop participants is that soil and sediments, which are thought to contain proportionally fewer pathogens than fecal sources, should make larger contribu- tions to indicator densities in surface water samples in IWs than in CW. Differences in hydrogeology that change indicator densities. The scale of each IW is determined by climatic conditions, geology, and ecology for that watershed. The sites for land-based contamination of IW are many, because waterborne pollutants enter IW from multiple sites as it flows downstream. Because the volumes of water in many IW sites are relatively small and land-based pollutants are often close to these sites, the dilution of pollutants is more limited in streams than in coastal settings (Olyphant et al. 2003). Parameters such as flow and turbulence vary ovlume 118 | number 6 | June 2010 • Environmental Health Perspectives