CONAMA Framework Resolution 357/2005: spatial and temporal analysis of water quality legal compliances in rivers and reservoirs from Sao Paulo State, Brazil (2005-2009)

The CONAMA Framework Resolution 357/2005 fixed the conditions for establishing water quality categories in Brazilian aquatic systems. We assessed the levels of non-conformity among the water quality in rivers and reservoirs from Sao Paulo State (SP, Brazil) and their framework. We analyzed data (n = 43,897) from total phosphorus, dissolved oxygen, nitrate, turbidity and Biochemical Oxygen Demand of 360 sampling sites within the 22 UGRHI (Water Resources Management Units) in SP from 2005 to 2009. The situation was unsatisfactory for total phosphorus and dissolved oxygen, mainly in the industrial UGRHI. There was no significant water quality improvement in relation to some of the studied variables within these five years, which indicates the need for directing investments on tertiary domestic wastewater treatment and mitigation of non-point pollution loads.