The natural environment of the QC s

The natural environment of the QC systems consists
of rural areas where agriculture is the main economic activity. Higher
concentrations of chlorophyll A occurred in the raw waters of the QC
systems, possibly associated with the use of phosphorous-based fertilizers
within the source watersheds (Sharma and Agarawal, 2009;
Tabinda and Ayub, 2010). Source waters supplying the QC systems
had a higher average turbidity than those supplying NL systems. This
might be explained by the type of raw waters under study (QC: 9 rivers
and 5 lakes, NL: 3 rivers and 9 lakes — See Table 1). However