FERNANDES, R. M. L.; http://lattes.cnpq.br/7809095152261180; FERNANDES, Rossana Maria Lucas.
Resumo:
This work analysed the physic-chemical and sanitary qualities of São
Salvador dam and its principal influent, rivers São Salvador, located in Sapé
municipality (7° 06'S; 35° 14'5"W), in the lower catchment area of Paraiba river
at the geographical microregião of Agreste Paraibano. The main sources of
pollution and their influence in the spatial and temporal distribution of the
parameters the effect dry and wet seasons were also analysed.
Samples from 3 points in the river and 7 points in the lake were collected
month from feb-jul/96 (rainy season) and sept-dec/96 (dry season) and
analysed for faecal coliform, faecal streptococci, E.coli, heterotrofic bacteria,
temperature, pH, electrical conductivity, dissolved oxygen, B0D5 , total
phosphorus and soluble phosphate, total and suspended solids, following APHA
(1989, 1995) and Rodier (1975) recommendations.
During the hydrological cycle, pH and EC were constant while nutrients
levels (N and P) and suspended solids values presented high fluctuations due
the influence of dry or wet seasons, land erosion, domestic sewage
contributions and micro-organisms metabolism (photosynthesis, assimilation's
and biodégradations process).
High values of faecal bacteria indicators (faecal coliforms, faecal
streptococci, E.coli) showed correlation with organic matter of faecal origin.
Accordingly to CONAMA Standards 20/86 both São Salvador stream and
reservoir was suitable for restricted irrigators and animal use. Only sampling
points with water quality belonging to class 2 were appropriate for bathing,
irrestricted irrigation and aquiculture.
To improve water quality and delay eutrophication there is need to
optimise the sewage treatment plant to reduce the negative impact of final
effluent, recovering of marginal native vegetation, divertion of irrigated agroecossystems
and control the recreational water use.