Animal Waste, Water Quality and Human Health

these organisms have provided limited or uncertain information, and are not alwayssuited for routine laboratory use (Johnson et al. 2004).Due to current limitations, MST methods may be better applied to specific siteand catchment investigations. For example, MST may be applied tounderstanding specific water quality issues and provide useful information ondiffuse sources of pollution. Data must, however, be interpreted with caution andsampling strategies need to be robust and relevant. The impacts of point sourcescan be readily monitored using traditional bacteriological testing; MST is notalways needed (though it can provide evidence of specific effects). The use ofultraviolet (UV) disinfection can complicate detection of bacteria using thepolymerase chain reaction, as the bacteria are killed, yet the DNA may persist(Bae & Wuertz 2009). However, it may be used to suggest qualitative changesresulting in water quality degradation following rainfall events, which can impactshellfish and bathing waters, where increases in faecal bacteria may originatefrom agricultural run-off or from raw sewage through a discharging CSO(Stapleton et al., 2009).The application of source attribution techniques such as MST to at least someroutine monitoring may be operational in many countries. However, it is still inits infancy, which limits the number of case studies available for detailingremedial action based on source tracking data. Additionally, it may not alwaysbe clear to a regulator what action to take once a source has been identified.Frequent spills from a CSO can lead to discussions with site operators aboutpossible solutions, but diffuse pollution and the complexities of environmentalvariables, even when assessed with MST and quantitative source apportionment,may still be challenging (Kay et al. 2007). The utility of MST as a sourceattribution technique is further discussed in Chapter 9.8.2.5 Sanitary surveysExposure interventions 289Tools of a non-microbial nature may also prove beneficial in identifying principalsources of faecal contamination. They include sanitary surveys (Kinzelman &McLellan 2009). A sanitary inspection or survey is an assessment tool designedto evaluate the principal sources of faecal pollution impacting water quality(Bartram & Rees 2000). Comprehensive sanitary inspections should categorizeall potential direct and indirect contamination sources in order to provide thebest estimation of health risk as part of a suite of assessment tools includingfaecal indicator organism assessments and source attribution techniques (see:Chapter 9). Proper sanitary surveys are indicative of contamination sources butthey lack the capacity of definitively identifying the source of faecal indicatororganisms or pathogens.