Transporte de resíduos sólidos flutuantes em rios urbanos dominados por maré na região Norte do Brasil

Abstract

The rivers that cut through metropolises are considered important ways for the waste generated on the continents to be transported to the oceans. Estimates of waste flows in rivers in the Amazon coastal zone remain uncertain due to the influence of hydrodynamic processes (tide, currents and flow), and above all, the lack of data on the type and amount of solid waste floating in the rivers. Therefore, the main objective of this study was to quantify and estimate the fluctuating waste fluxes at different time scales in tidaldominated rivers of the Amazonian coastal zone. Visual quantification took place over 12 hours (6 to 6 pm) in the flood and ebb tide stages, in the dry and rainy periods, in the rivers Acará, Guamá, Guajará, Tucunduba and Tamandaré. The estimate of waste transport in different tidal stages and seasonal periods was calculated considering the amount of waste in a time interval (hour, month and year). A total of 19,654 solid waste was quantified in the rivers studied, 71% of which was plastic materials. The residues from the rivers that cut through Belém (Tucunduba and Tamandaré) are exported to the rivers that surround the capital, while in these rivers, the residues present a bidirectional flow, suggesting imprisonment reflecting the influence of hydrodynamic processes (tidal current and flow). This study presents the first estimate of transport in rivers on the coast of Pará based on real observations, indicating an estimate of annual transport that varies between 3 and 549 tons/year.