Microbial Risk Assessment: Application and Stages to Evaluate Water Quality

Abstract

This works presents the stages of microbial risk assessment and its application in the evaluation of drinking and recreational water quality and further the risk of diseases attributable to pathogens present in these waters. In Brazil, infectious diseases were responsible for 5.1% of deaths, the fifth place of mortality cause. Most affected people are children, elderly and immunocompromised population. According to Brazilian Health Ministry, from 1995 to 1999, environmentally-caused diseases occupied 3.4 million beds in hospitals. All of these reports showed a very public health concerning scenario.

This tool can provide bases to establish tolerable (acceptable) risk and thus defining the protection level to human health for each hazard, in this case, pathogens microorganisms. The stages are hazard identification, exposure assessment, dose-response relationship and risk characterization. The hazard identification is related to the presence of microorganism and toxins and their association with specific diseases. The exposure assessment includes the intensity, frequency and duration of human exposure to a specific agent. The aim of dose-response relationship is to acquire a mathematical relation between amount of microorganism (concentration) and adverse effect on human health. Risk characterization represents the integration of the previous stages. Risk assessment is a tool used for decisions making and providing information to take measures of control and interventions, as well as to evaluate the impacts of these actions. It provides support to a decision-making process based on scientific results in several areas of the knowledge. In Brazil, risk assessment is a recent area of research, but promising for the management of water’s quality such as catchments points and recreational waters, in special in periurbans areas of metropolitan regions, which show precarious sanitary conditions.