Feasibility of a daly of no more than 10-4 per person per year for water reuse in agriculture, in developing countries

DALYs are a measure of the health of a population or burden of disease due to a specific disease or risk factor. It evaluates the time lost because of disability or death from diseases compared with a long life free of disability in the absence of disease. DALYs are calculated as the sum of years of life lost by premature mortality (YLL) and years of healthy life lost in states of less than fully health, i.e., years lived with a disability (YDL), which are standardized by means of severity weights, thus: DALY=YLL+YLD. WHO has established for wastewater use in irrigation the same reference level of health protection as established for drinking water quality, i.e., the additional burden of disease from consuming water irrigated food should not exceed 10-6 DALY (Disability-Adjusted Life Years) loss per person per year (pppy). Such a restrictive risk is almost impossible to be attained in most developing countries which may not be able to afford the cost of wastewater treatment and of other protective measures, even for restrict irrigation. This paper analyses which protective measures are able to be implemented in developing countries and proposes a tolerable disease burden of no more than 10-4 DALY per person per year. In order to evaluate this proposal it is mandatory to adopt a methodology of cost/benefit, through the development of epidemiologic studies and the identification of local characteristics and constraints, particularly the ones related to public health, technical, socio economical and environmental conditions.