Animal Waste, Water Quality and Human Health

jurisdictions, regulation targeting microbial movement is relatively new andlessons are still being learned; and there is little substantive experience withregulation targeting human exposure.At the interface of narrowly-defined regulation and wider policy, and includingarrangements for inter-sectoral coordination, are the differing perspectives of theindividual facility or farm and the collective impact of many such facilities orfarms on a single catchment, including its multiple and diverse uses and thevalue and utility of such uses – extending into the associated coastal zone. Thisalso implies an understanding of overall microbial load and of associated healthrisks (Kay et al. 2004).Benefit-cost analysis (BCA) is one means to pursue regulatory efficiency, bydemanding that both costs and benefits be described and to the extent possiblequantified; and using the evidence derived to compare alternative responses andto reflect on means to minimize cost and maximize benefits of adoptedapproaches (Hahn & Tetlock 2008). Application of BCA to livestock excretamanagement for health protection has not been attempted in large part becausebenefits are poorly understood. For example, many interventions will operate on anumber of pathogens and not a single agent. The outbreak of waterborne diseasein Walkerton, Ontario, Canada that resulted in seven deaths and over 2300 casesof gastrointestinal illness was associated with infections by both E. coli O157:H7and Campylobacter jejuni. Intense rainfall is thought to have washed cattlemanure into a well which served as the water source for the town (Auld, Klaassen& Geast 2001). The nature of benefits is also evolving as greater attention is givento energy and nutrient recovery; and as the appreciation of the value of therecovered resources increases, so the benefit component of BCA expandsaccordingly.1.3 OPPORTUNITIESIntroduction 7There may be opportunities to look for alternative solutions applicable to animalexcreta as compared to those associated with the monitoring, management andregulation of human faecal contamination.Direct targeting of specific pathogens has received little support in monitoringof human faecal contamination, in part because of the large number of potentialpathogens, both known and unknown. However, since the number of crediblezoonotic pathogens from any given animal species may be more limited, the roleof direct pathogen monitoring may merit re-appraisal.High-intensity production systems presently account for three quarters ofchickens, two thirds of milk, half of eggs, and a third of pigs (FAO 2009). Moreintensive operations (such as the zero-grazing option: cattle managed exclusively