Public Health Impact

The link between the environment and public health has been well-established (Postel 1997; Gleick 2000; Conway and Pretty, 1991; Altieri 1995; Pretty 1995, 1998; Mason 1996; European Environment Agency 1998). Over the past 15 years, an emergence of a minimum of one new pathogen per year that is transmitted through the environment has been recognized as a public health threat (WHO 2003). There are multiple facets of waste treatment and the reuse of solids that can bring humans in direct contact with pathogens that pose potential health risks. The quantification of these risks is an emerging area of research in environmental health. The potential risks are dependent upon multiple factors including the infectivity of the organism and route of exposure. The type of organism plays a key role in health impact. In general, about half of the individuals infected with an enteric pathogen become ill (Rose et al., 1995; Haas et al., 1999). The quantification of exposure is where the majority of uncertainty lies. Risks from land application of wastes can be better quantified with more information on actual ingestion or inhalation rates, and duration of exposure during these activities. Data on the concentrations of pathogens in the different types of wastes after treatment are also needed. The linkages between waste treatment and public health will be discussed along with the implications of treatment, emerging pathogens and regulatory concerns.