The objectives of this project was to monitor trace metals (Cr, Pb and Zn) in sediments and in algal tissues -Padina sp., Ulva sp. and Enteromorpha sp, in the estuaries of GRNW, St Louis River, Flic en Flac rivulet, Grande Riviere Noire estuary, Petite Riviere Noire estuary and Tamarin estuary during summer and winter months starting July 2000. Dissolved nutrients (phosphate and nitrate) and master variables (temperature, salinity, dissolved oxygen, pH) were also monitored in the different estuaries.