| Sumario: |
Water quality information is essential supporting decision making in water management
processes. The lack of information restricts, at some point, the implementation of adequate sanitation,
which is still scarce in developing countries. In this study, an ecosystemic water quality assessment
was conducted in the Virilla river in Costa Rica, in a section of particular interest for future
sanitation development. It included the monitoring of physical, chemical, microbiological and
benthic macroinvertebrate parameters from 2014 to 2016. Mutivariate statistics and water quality
indexes were used for data interpretation. Results indicated that water quality decreased downstream
towards more urbanised areas. Particularly, extreme values of phosphorous, nitrogen and E. coli
were found. Sample sites were grouped in two clusters, which were consistent with land use.
Benthic macroinverterbrates diversity was predominantly represented by Baetidae, Chironomidae,
Leptohyphidae, Hydropsychidae, Simuliidae and Physidae. They were mostly influenced by water
temperature, nitrite, ammonium, soluble reactive phosphorous, total solids, alkalinity, nitrate and
total suspended solids. Three water quality indexes consistently showed the poor condition of the
water body. The overall results indicate that the main sources of pollution in the river are likely to
be wastewater discharges. Thus, special efforts should be undertaken regarding its regulation in
the country.
|