Contenu du sommaire : Risques et pollutions industriels et urbains

The article defines the notion of a major technological hazard and its official measurement. Control of urban development around dangerous industrial sites would appear to be the best form of management, although it needs to take account of local conditions.

In order to analyse the relationship between Major technological hazards (MTH.) and cartography, the author first stresses the complexity of relations between hazards and space, as well as the different dimensions to be taken into account for the evaluation of MTHs. Second, the mapping process associated with the evaluation methods of hazards is presented according to the different ways of approaching the MTHs. Finally, the role of the map in the prevention process and management of MTHs is highlighted, as well as the role of Geographical Information Systems as a decision-aiding tool.

During the revision of the master plan for the region of Ile-de-France, attention was drawn to the delicate issue of taking account of major technological hazards. On an experimental basis, an evaluation of such risks was undertaken with respect to an oil-storage depot in the inner suburbs of Paris. For this purpose a methodology was developed giving emphasis to the spatial dimension of hazards and introducing the notion of its social cost. An oil-storage depot involves the transport of a dangerous substance to serve customers. Evaluation of the two aspects of risk (the site and the transport) demonstrated, in terms of cost, the importance of the transport element. This is due essentially to the greater frequency of road accidents involving lorries transporting dangerous products.

The chemical industry is a major component of Lyon's heritage. Its birth and development are rooted in specific socio-economic features of this area. Nevertheless, the growth of this industrial system and its location have resulted in pollution and hazards. For certain local officials these represent an unacceptable risk, especially as direct employment in this branch and its long-term viability are questioned. However, concerted action between industrialists and local authorities may allow the integration of environmental issues to the greater efficiency of the productive system and its better interaction with the local socio-economic system.

For the small industrial town of Saint-Fons (located in the south of the Lyon metropolitan area) the implementation of a national policy to control urban development close to hazardous sites was the cause of several years of conflict, followed by negotiations, between government administrative services and elected representatives of the local authorities. Initially, the solution to the problem of conflicting logics between risks and society was sought through technical expertise and the mapping of dangerous zones. Subsequently, the area's social reality created a new negotiating 'space' within which the balance of power between state services and local politicians was redefined.

Saint-Fons and Pont-de-Claix are two small, industrial communes of recent origin where the chemical industry covers much of each their areas. Initially, high-risk zones covered the whole of each commune, posing a particularly acute problem of the co-existence of urban and industrial areas. In both cases, the spatial extension of these risks was considerably reduced between their initial mapping and their inclusion in local land-use plans. Pont-de-Claix provides an example. The impact of high-risk zones on land and house values in Saint-Fons is still relatively unimportant. However, the constraints resulting from these zones completely call into question the urban development projects of local authorities.

Over the last fifteen years the industrial basin of Lacq, which developed around a natural gasfield, has experienced a very different pattern of development from that initially intended. State control of major groups in the chemical and metallurgical industries affected by the energy crisis, industrial reconversion policies and the emergence of a French 'sunbelt' have all provoked major economic changes along the Pau-Lacq axis. More specific environmental factors would appear to support the emergence of a pole of dangerous chemical industries, linked to the boundaries of old protection areas and the reinforcement of waste control legislation.

The example of the Nord-Pas- de-Calais coalfield shows that dangers remain after mine closure. The main risks concern subsidence, disruption of surface and underground hydrological systems, contamination of rivers and underground streams, the safety of mine shafts and slag heaps and polluted derelict land. Doubts about the length of time needed to rectify such damage and the related cost pose complex problems of responsibility which should be solved during the current process of terminating concessions.

The continuous increase of atmospheric pressure and of the number of unusually long- lived high pressure patterns during the 1988-1993 winter seasons (stability connected with a rain deficiency and light winds) caused peaks of pollution (under an anticyclonic mass characterized by a temperature inversion) over the Lyon area. The Air Quality Preservation Procedure (AQPP) set up in 1984 to reduce or to prevent the pollution peaks is effective.

The Regional Office of Pollution Control (L.I.S.), founded in Essen (1963) disposes of huge technical and financial means compared with similar organizations. Its various functions deal with pollution control and information as well as basic research and education.

This paper aims to show that the future of seperate collections of household refuse remains to be confirmed. Despite sound intentions and the extension of such collections to new areas, they concern only specific types of refuse and the results vary, notably in relation to public awareness, the social profiles of residents and housing characteristics. The sustainable development of such programmes requires strong encouragement, accompanied by a change of attitudes in society.