4.2.3 Total Phosphorus
The total phosphorus dissolved in water in T1 (Figure 3E), presented
values higher than those recommended by CONAMA Resolution 20/86, which
is 0.025 mg l-1), compared to T2 (Figure 3F). The values of phosphorus
for T2 of 0.10, 0.16 and 0.16 mg l-1, for February, October, and
December, respectively, were below the values of 0.21, 0.13 and 0, 21
mg l-1, except for October, the values observed in T1 were higher than
those recorded in T2, except for the peaks recorded in December 2010 and
October 2009 and 2012, which reached more than 0.30 mg l-1, even below
the peaks that occurred in T1 in 2001, 2002, 2003 and 2005, which
reached 0.50 mg l-1, in December 2005 (Figure 3E).
The results show lower values than the values obtained by Donadio et
al. (2005) who evaluated the water quality in a Watershed in
Taquaritinga, SP, whose predominant soil is the Ultisol and the average
values of phosphorus in the water for the dry period of the year was
1.58 mg l-1and for the rainy season was 4.32 mg l-1.
The results of phosphorus, found by Pinheiro et al. (2014), who studied
the use and occupation of soil and the relation to water quality in two
sub-areas of Rio Duas Mamas Watershed in Santa Catarina, were 27.3 and
41.6 mg l-1 and, were higher than the results found in the present
study. This was because in SW2 there were banana cultivation and
cultivation areas for annual cycle crops, despite the large percentage
of remaining natural forest, in both cases.