“Not seen, not considered”: An evaluation of differential perceptions of environmental risks using Perception-Based Regional Mapping: the case of heavy metal dispersion extent in the Plain of Mornag facing old plumb mine spoil tips of Jebel Ressass (Tunisia).

Abstract : The Mornag plain—which is dominated by a mountain, Jebel Ressass—has been exploited for various uses for millennia. There are still huge slag heaps around the old lead mines at the foot of the mountain. Olive trees are cropped intensively in the plain, although this agriculture is threatened by the expansion of the suburbs of Tunis nearby. The mapping of environmental issues perceived to be important by local stakeholders in the Mornag plain was carried out. This was achieved by using perception-based regional mapping (PBRM) to inexpensively assess the spatial extent of all the perceived threats and risks to the environment as well as its vulnerabilities in this region. All of the resulting PBRM maps were integrated with a GIS and then merged to obtain a spatial database of the environmental risks that affect this territory. Several risks and nuisances were found to be linked to the presence of Pb mine dust as well as dust from the nearby quarry. Household waste and garbage appear to be the main environmental concerns to local stakeholders. The problems are due to the gap between new periurban consumption practices in suburban Tunis and rural municipality budgets. Other agriculture-related nuisances highlight the gap between the vision of a preserved rural area and the agro-industrial reality. PBRM was found to be a useful tool for assessing the effects of the accumulation of multiple environmental risks on a territory rather than focusing on one factor