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�{Jlr-2 3-1:08 38:013 rrRG11 DHS--Eh ()i RCN TO R CCH CN ',.,HLLEY P.e3 <br /> Willi= H. Crooks <br /> R*t 2 <br /> Mlile itis is a frequently &served viral disease of excess <br /> ir-idence a=ng persons who have =)gn_sted water grossly oorrIzated by <br /> inadequately dl sinfected wastewater, vitt:ses that could be present in effluent <br /> could also be those that could cause the more incapacitating infectious <br /> hepatitis, meningitis, heart a :o lies, and respiratory diseases. Protozoa <br /> whose viable cysts cmdd be present in effluent irrUude those that could cause <br /> giardiasis, arx�-eebic dysentE , and the potentially fatal balantidial <br /> 'There is no excess incidence of infection that the medical ==pity could be <br /> cq)e-ted to consider acceptable in light of the seriousness of some of the <br /> dose, that can result from infections with organisms of sewage origin. <br /> 'Thus the above-cited anxlitions aro macoeptable. <br /> 2Mp <br /> and Disa2.� Ar.►orx� - - <br /> Epidemiologic studies of swi. s that had sworn in fresinater bathing waters <br /> off beaches of take Erie and IWstCM iake were reported by EPA as showing a <br /> strozcorrelation between incidence of swining"associated gastrcenritis <br /> and centrations of mi of se'.rage origin. That cbservatian <br /> pertaIrled to e�=ess cUsease incidence rangi.rg frm 14.7 per 1000, down to 0.5 <br /> per 1000. Pending our Future awareness of any other epid.mmlolocric study <br /> showing such a muse-effect relatio:ship at incidences less than 0.5 per 2000, <br /> we shall consider that inciderxca the 10-e established swage-caused <br /> incidence of disease -=-jg swurw-rs The incidCmce of infection can <br /> reasonably be asstm ed to have been subst t ally higher than the incidence of <br /> disease. <br /> In sloping the prat EPA bacteriological criterion for water contact <br /> recreation use of fresh water, the National Technical Advisory C=mittae to <br /> the S� of the Interior (who was then responsible for the predecaor <br /> agency to EPA) selected as the criterion one--half the bacterial �ati.on <br /> at which a statistically significant --JL-=ung-as-sociated gastrointe final <br /> illz�ss had been lambelia itch. tOur referez=hat halving j tion ofon <br /> for <br /> vizu_ses and gi.ztzrii.a �' <br /> organi,vs at prdbabilities 0.005 - 0.5 per=-,t halves the excess prabaabilitY <br /> that infection will be cont=act-ed. Half tre ozganim concentration at which <br /> the observed disease incidence was 0.5 per 1000 wood surely have resulted in <br /> an mss infection insider greater than 0.25 per 1000 -- more likely an <br /> infection incideroe- ten or more tins that. VhIle an excess infection <br /> incidence 0.25 per 1000 should not be ccrsidered acceptable, it is used here <br /> as a criterion to define acceptable waste manageMent. <br /> rnrx3�tions with Treat exit or La..'x1 Oi.spp!sal Greaten <br /> IP treatment resulting in a median coliform density of 2.3/100 <br /> 8 l it could <br /> al1C� l. ware'able excursions to 23/100 ,Iprcvided, disrhrc3a <br /> a <br /> result in viral aril prctozcan infection incidences of rcixhdy 1.4 and 1.7 per <br /> 1000 in Dredger Ort aid 0.9 and 1.1 in mite S1atgh. At that level. of <br />