HUMAN IMPACTS ON CORAL ECOSYSTEMS AT MAURITIUS ISLAND - COPROSTANOL IN SURFACE SEDIMENTS

Coprostanol, a reliable marker of fecal pollution, has been determined from 57 marine sediment samples in the west, the south-west and the e ast of Mauritius. 84% of sediments contain more than 0.2 mg per kg of coprostanol, indicating significant fecal pollution. Contamination was detected at all the sites studied, except in 'Tamarin' bay (south-wes t coast) which is strongly affected by wave action. 'Port-Louis' estua ry (capital, west coast),'Grande Riviere du Sud-Est' estuary, the zone near the hotel Touess-rok and the exit of 'Trou d'eau Douce' channel (east coast) are the sites most contaminated by sewage pollution, with coprostanol contents higher than 1.5 mg per kg. Sewage impact decreas es with distance from the coast and depth. Lower coprostanol concentra tions are generally measured in the open sea, but at 190 m depth (sout h-west coast) the coprostanol concentration is always relatively high (0.9 mg per kg).