Interlocking Biological and Political Uncertainties in Public Decision Making : A Case Study at Mellery (Belgium)

A central question in health hazard associated with environmental pollution is the evaluation of level of exposure to a mixture of carcinogens and the estimation of the global health impact on the residents. The point is important to found a public health decision for site intervention or residents relocalisation. Belgium had to face such a problem at Mellery, a village which became internationally famous some years ago, when local residents denonced a local pollution originating from an industrial waste depository facility situated only 500 m from the centre of their village, in a former sand quarry.

A central piece of the actions of the authorities was the original campaign organised to measure directly the level of exposure to carcinogens of a large group of voluntary local residents, children included, by measuring biomarkers of exposure in blood lymphocytes : for its high sensitivity, the frequency of sister chromatid exchanges (SCES) had been chosen. This biomonitoring method, quite commonly used to monitor occupational environment, had never before been applied to evaluate the potential health impact of the environment on a general population. Such data, although sophisticate and integrative, are only indicators of exposure and cannot be used, so far, as individual quantitative predictors of the possible evolution of the health of the individual persons. First designed as an epidemiological study, the campaign at Mellery revealed so high exposure levels that the experts did not keep with the original experimental line and decided to release individual information to the concerned persons, without much preparation nor risk communication policy. Several groups (experts, local doctors, local and regional authorities, public agencies and residents associations) were active integrating the information in their respective discourses, giving them specific interpretative and competing meanings. Any scenario for intervention had to be embedded in some meaningful and legitimating discourse : a quite difficult task for the authorities.

The evolution of the expertise system used for public decision-making were marked by several such uncertainties (geological, biological, medical) but also by the difficult integration of health related aspects within environment interventions in the regulatory structures in Belgium : health responsibilities are scattered between federal and "communautaire" bodies, while most of the environmental actions are funded at the regional level. In this first heavy case, the young regional institutions reacted in a disorganized manner: they choose to not put at risk their frail power equilibrium and to not reconsider the attribution of the responsibilities.

The authors propose to analyse how peculiar interlocking of the biological and political uncertainties were at the core of the general failure in public risk management around this landfill site: Mellery, after 10 years and a huge budget for site treatment, is still a nightmare for environmental authorities in Southern Belgium.