Impactos ambientais da zona rural e urbana na qualidade da água do Ribeirão das Araras
Abstract
Agriculture, urbanization and industrialization are some of the human activities
that are constantly generating negative impacts on the environment. Much of
this degradation directly affects exhaustible lotic systems that are important
sources of water supply for the population. This provides the aggravation of
problems in obtaining clean water. From this context, the present study aims to
assess visual characteristics of habitats in the longitudinal gradient of Araras
River and along with the seasonal monitoring of physical and chemical
parameters of water quality, state of the natural environment conservation
status, while characterizing the changes caused by anthropic activity. For the
survey data, 6 points of evaluation were select, ranging from stretches of rural
and urban areas. The evaluation took place using the Rapid Assessment
Protocol of Habitat Diversity, which at the end of the application, defines the
environment preservation level. The monitoring with collection of water samples
complied with the climate (drought, intermediate and wet), totaling 13
parameters measured, submitted to analysis of simple variance (ANOVA), using
as multiple comparisons test the Tukey test at 5% level of significance. Both,
the results of water quality analysis and the PARs analysis showed degradation
of shares in the Ribeirão das Araras, as a result of human activities. Regarding
seasonality, there was a significant difference only between the parameters:
total nitrogen, total phosphorus, chloride, sulfate and electrical conductivity, but
without apparent climate relationship. Total phosphorus parameter, except for
the 3rd poit, showed values above the limit, established by CONAMA, in the
Resolution 357/05, with higher concentrations in the dry season. However, in
the 5th point, it was highlighted by having higher concentrations in almost all
parameters and also by disagreement in turbidity parameter in the interim
period. The protocol described the whole gradient evaluated as amended (48.6
points). The points of greatest environmental criticality were the points 4 and 5,
both classified as impacted. Together the tools showed that the points located
in the urban area (4 and 5), are the most affected by human activities, mainly
because of the margins occupation, channeling, rectification, removal of riparian
vegetation, domestic sewage disposal, garbage on the banks, erosion, etc. So,
the low-cost of tools adopted here, Ecokit and RAPs, provided to be an
efficient way to evaluate the water resources.