COPPER MINE TAILING DISPOSAL IN NORTHERN CHILE ROCKY SHORES - ENTEROMORPHA COMPRESSA (CHLOROPHYTA) AS A SENTINEL SPECIES

The study assesses the ecological impact caused by the El Salvador unt reated (1975-1990) and treated (1991-1994) copper mine tailings on roc ky intertidal communities in and around the dumping site at Caleta Pal ito, northern Chile. Ecological changes are monitored for 16 years in polluted and unpolluted sites within a geographical area of 90 km. Cop per concentration levels in water and the intertidal Chlorophyta E. co mpressa are presented. The results confirm a notorious reduction in th e number of species and significant differences between polluted and u npolluted intertidal communities. At polluted sites, following the ini tiation of the disposal, all species of invertebrates and algae disapp eared and primary space (rock) was partially or completely dominated b y E. compressa along more than a decade. Its persistence in these site s supports the view that this taxon is a sentinel species resisting hi gh levels of copper pollution. During the past four years, following t he steps given to treat the tailings, at polluted sites there are prel iminary indications showing increases in the number of species of alga e and invertebrate. The need for future monitoring to elucidate ecosys tem restoration processes is discussed.