Table A3.10 Tolerable pathogen levels and required reductions for different uses of roofwater Tolerable units per L) Use Reference concentrate- pathogen Required reduction (or (infectious safety margin) 0.76 Not required (–1.1 log10) Campylobacter Equivalent of municipal, jejuni including open-space irrigation, dust Implications Treatment suppression not (exposure = 50 mL/ requireda person/year) 0.057 17.2% 0.1 log10 Equivalent of dual Campylobacter reticulation for indoor jejuni and outdoor use Implications Treatment (exposure = 670 mL/ not person/year) requiredab Equivalent of 0.078 Not required (–0.1 log10) Campylobacter commercial food crops jejuni Implications Treatment (exposure = 490 mL/ not person/year) requireda 0.76 Not required (–1.1 log10) Campylobacter Equivalent of non-food jejuni crops (eg trees, turf, woodlots, flowers) (exposure = 50 mL/ Implications Treatment not person/ requireda year) 0.38 45% 0.25 log10 Campylobacter Equivalent of firefighting jejuni (exposure = 1000 mL/ person/year) Implications Treatment not requiredab a Treatment is not required if exposure controls can be maintained as recommended. b Even though the value is positive rather than negative, treatment is not required due to the very small log reduction predicted being outweighed by the conservatism in the estimates.
Table A3.10 Tolerable pathogen levels and required reductions for different uses of roofwater Use Reference pathogen Tolerable concentrate- (infectious units per L) Required reduction (or safety margin) Equivalent of municipal, including open-space Campylobacter jejuni 0.76 Not required (–1.1 log10) irrigation, dust suppression (exposure = 50 mL/ person/year) Implications Treatment not requireda Equivalent of dual reticulation for indoor Campylobacter jejuni 0.057 17.2% 0.1 log10 and outdoor use (exposure = 670 mL/ person/year) Implications Treatment not requiredab Equivalent of commercial food crops Campylobacter jejuni 0.078 Not required (–0.1 log10) (exposure = 490 mL/ person/year) Implications Treatment not requireda Equivalent of non-food crops (eg trees, turf, Campylobacter jejuni 0.76 Not required (–1.1 log10) woodlots, flowers) (exposure = 50 mL/ person/ year) Implications Treatment not requireda Equivalent of firefighting (exposure = 1000 mL/ Campylobacter jejuni 0.38 45% 0.25 log10 person/year) Implications Treatment not requiredab a Treatment is not required if exposure controls can be maintained as recommended. b Even though the value is positive rather than negative, treatment is not required due to the very small log reduction predicted being outweighed by the conservatism in the estimates.
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