Considering the growing importance of environmental exposures to the health of the population and the contribution that the spatial component of this relationship has to the understanding and prevention of these environmental hazards, we developed an environmental-health geographic-information-system (EH-GIS) for the state of São Paulo (population 32 millions), in Brazil, which is intended to be used in collaboration with the Local Health Authority as part of their Health Surveillance System, particularly to address the frequent issue of contaminated land sites. The objectives of this EH-GIS are to improve mechanisms for rapid risk assessment and management, identify actions needed to evaluate and mitigate or prevent human health effects, assess any current or future impact on public health and develop recommendations to the public regarding exposure to environmental hazards. In doing so it intends to help the Local Authority devise sound environmental health policies.
Three different levels of analysis are used: municipality, districts, and census tract. Information on key environmental hazards such as water quality, air pollution, location of waste incinerators, contaminated fields, and others are being gathered. Outcomes of interest include pregnancy outcomes, cancer mortality and hospital admissions for several conditions. Statistical analysis for spatial data accounting for spatial autocorrelation, cluster analysis and random effects models are some of the methods being used.
Maps of air pollution exposure for the city of Sao Paulo were used to identify high-risk population groups. This information coupled with the geographic distribution of other characteristics such as the social dynamics of the population revealed unequal distribution of risks. Mapping of other environmental hazards helped identifying target areas for rapid assessment and evaluation.
This approach proved useful not only for etiologic purposes but also for risk identification and assessment. It can be used by local health professionals and even the local population to understand the potential health threats posed by specific environmental hazards that may lead to further health actions or studies.
Department Of Preventive Medicine-University Of Sao Paulo