Relationship between phosphate and the formation and degradation of organic matter in the water system that crosses the municipality of Mogi das Cruzes (São Paulo, Brazil) R. M. Munin, Bruno O. Sutti, V. G. Chiozzini, Elizabeth Santos Braga

Abstract

Phosphate is usually the limiting nutrient for the productivity of most continental waters, which makes its study associated with the processes of formation and degradation of organic matter in urban eutrophic systems relevant in order to improve the limits established by current legislation, as well as to obtain viable recovery measures. The present study evaluated these processes in four streams that cross the city of Mogi das Cruzes (SP), considering the following environmental parameters: pH, dissolved oxygen (Winkler), phosphate (colorimetric), particulate organic matter (Gravimetric), chlorophyll-a and pheophytin (colorimetric). In general, the low values ​​of oxygen saturation and chlorophyll-a demonstrated that phosphate (and other nutrients) did not promote the eutrophication process in the stations of these urban streams, thus evidencing a high allochthonous source of MOP. Based on this, it is concluded that important anthropogenic sources of organic matter, mainly diffuse ones, are acting in the water system that crosses the city of Mogi das Cruzes, thus alerting to the lack of basic sanitation in certain neighborhoods, mainly those that border the water system.