Eutrophication and bacterial pollution caused by industrial and domestic wastes at the Baixada Santista estuarine system - Brazil

Baixada Santista's region is world famous for its high levels of pollution, which are related to industrial, port and urban activities. Around the ind ustrial pole of Cobatao city, high nutrient concentrations are found such a s nitrate > 90 mol l(-1) N NO3- and phosphate > 24 mol l(-1) PPO4-3 A clear gradient of dilution from the estuary's interior to its mouth is present a long the natural channels, but does not reach low concentrations for all el ements in the Santos Bay. Artificial urban drainage channels present accent uated differences of the nutrient concentrations inside and outside each lo ck. The inner channel waters, show low average values of salinity (1.33 PSU ) and oxygen (similar to 2.0 ml l(-1)); pH under 8; high averages of nutrie nt concentrations (ammonium similar to 40 mol l(-1), nitrate similar to 42, phosphate similar to 2.96 mol l(-1), silicate similar to 119 mol l(-1)); h igh total and faecal coliform averages (3566 x 10(3)/100 and 1637 x 10(3)/1 00 ml, respectively), Outside of the channels, on the beaches, there were h igh nutrient concentrations at some points and accentuated total and faecal coliform averages (91 x 10(3)/100 and 28 x 10(3)/100 ml, respectively), Th e high TC and FC contents outside of the locks show the inefficiency of the actions to prevent pollution on the beaches, These facts represent risks t o local biota and human health. (C) 2000 Elsevier Science Ltd. All rights r eserved.