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1 <br />1 <br />' Pig 0.04 <br />sheep 0.4 <br />turkey 0.1 <br />The use of FC/FS ratio can be very helpful in pollution studies, especially <br />' where septic tanks are used. Establishing the source of pollution is very <br />important, especially where it is proposed or implied that implementation <br />' of conventional wastewater -management facilities will eliminate measured <br />coliform values. The ratio of FC to FS indicates the source of <br />' contamination as follows: <br />' FC/FS Ratio Source <br />0-.7 Animal waste <br />.7-1.0 Primarily animal waste in mixed pollution <br />' 1.0-2.0 Grey area - interpretation uncertain <br />2.0-4.0 Primarily human waste in mixed pollution <br />' 4.0+ Human waste <br />' It is very difficult and time-consuming to test for all pathogens, and the <br />coliform test is usually a sufficient indication of bacterial water <br />' quality. However, viruses may sometimes persist longer in natural systems <br />than indicator coliform organisms. It is also necessary to realize that <br />viruses can survive and be transported in the adsorbed state. This is well <br />' illustrated in a study in St. Petersburg, Florida, which investigated the <br />potential buildup of viral pathogens in soils and groundwater. It was <br />' found that viruses of fecal origin survived in Florida soils and passed <br />through as much as 5 feet of sandy soil during the dry season. Also, <br />' several months into the rainy season, a burst of virus appeared in 10 -foot <br />and 20 -foot monitoring wells placed downgradient from the original test <br />sites. <br />A large quantity of virus is not needed for a potential health hazard. The <br />' average virus density in domestic sewage has been estimated to be about 700 <br />viruses per 100 ml, but as many as 46,350 viruses per 100 ml have been <br />' detected in some parts of the world. It has been calculated that if a <br />' IRC.VB4 <br />6/4/87 <br />-15 <br />