This project collected a series of physical, chemical and biological parameters. The data consists of sampling carried out in January 1986, at which sampling cruises were realized in 60 stations. These data are relative to samples in the estuary (6-8 January), in the São Gonçalo Channel area (12-15 January), Tapes (19-22 January), and Pontal da Formiga (29-31 January), the northernmost sampled region. Of these, 17 stations were sampled in the estuarine region, and the remaining were divided in transects E-W and N-S, thus covering all regions of the lagoon. In the E-W direction, data were obtained from margin to margin. Water samples were collected at the surface and near the bottom using a plastic bucket or a 3 l horizontal bottle. SPM analysis were carried out gravimetrically on pre-weighted Gelman GA (0.45 μm pore size) by 'Laboratório de Hidroquímica' at 'Universidade Federal do Rio Grande (FURG)'.