Water Use and Risk Perception: mapping estimable epidemiological risk onto heuristic failure

Traditional epidemiological analyses predict preventive behavior when individuals perceive hazards as risky and out of personal control. Recent evidence has found that both controllability perception and heuristic failure may induce risky behavior, increasing potential for disease and injury outbreaks. Based on a representative sample of 352 respondents along the Rio Doce, in Brazil, we make use of Simultaneous Equation Modeling coupled with Thematic Net Analysis to understand how failure to interpret contamination mechanisms may underestimate the epidemiological risk in contexts of high level of river water pollution. Because affect heuristic is also important to prevent risky behavior by modifying personal risk perception, we include a measure of family members ever infected by waterborne diseases in our empirical models. Our descriptive results point to an apparent paradox of high prevalence of river water use and high scores of risk perception. Our regression results suggest a significant underestimation of perceived risk of contamination from water use among those who make use of the river for consumption and leisure, even after taking endogeneity into account in the models. Although many psychological studies suggest that controllability is the main underlying mechanism in this situation, our qualitative analysis reveals that risky behavior regarding use of polluted water relies on failure to understand the mechanisms for transmission of waterborne diseases. These results suggest that population-based epidemiological campaigns aimed to promote preventive behavior must focus on educational campaigns using simple and objective examples of the how waterborne diseases are transmitted.