The trace element contamination of coastal waters: A holistic approach to environmental monitoring surveys

Sustained monitoring programs are necessary to evidence the efficacy of regulatory controls on pollutant discharges and to assess the health status of ecosystems. Within this perspective, this study aimed to monitor the coastal trace element contamination of the whole Mediterranean, using Posidonia oceanica (L.) Delile as bioindicator. But sustainable coastal management also requires the development of appropriate classification systems intended, among other purposes, for environmental managers and policy makers. The combined utilization of several complementary monitoring tools - water quality scale, pollution index, spatial analysis - successfully led to the development of such an operational classification system: it allowed to assess contamination threats and to depict contamination gradients of the entire Mediterranean, while assessing more regional and local impacts. Consequently, such holistic approaches should be privileged to accurately monitor the contamination rate of coastal waters and to transfer relevant information on this composite problem to environmental managers and policy makers.