OSCILAÇÃO NAS CONCENTRAÇÕES DE METAIS EM TEMPO SECO NAS ÃGUAS DO RIBEIRÃO DOS MENINOS EM SÃO CAETANO DO SUL - SP

Abstract

Diurnal oscillation patterns in flow and metal concentrations are investigated in a urban river subject to strong diurnal seasonality due to effluent discharges (industrial and sanitary) by analysing quasi-continuos series of dry-weather flow rate and metal concentration measured in the Meninos Creek, São Caetano do Sul, in Brazil’s largest automobile industry district – in São Paulo State. The data available are a flow hydrograph and concentrations of six metals (dissolved iron, cooper and aluminium; total nickel, zinc and chromium) at two bridges separated by 720m along the creek. By analysing their time oscillations, one concludes that total metals partially settle on this riverbed stretch during low flow periods, and dissolved metals undergo reduction in concentration between the two bridges. This preliminary campaign suggests that this research may be carried on, based on a richer database, perhaps allowing for water quality modelling on this river stretch. Index Terms - Fluvial pollution, urban rivers, metals in river water, diurnal oscillations.