This research evaluated the effectiveness of the implementation of water resource preservation areas in the Hydrographical Basin of Andreas Stream, county of Vera Cruz, RS, Brazil, established through Payment for Environmental Services (PES), using an environmental monitoring program to assess physical, chemical and microbiological variables. The PES is linked to the "Water Guardian" project, which aims to ensure the preservation of water resources by paying farmers for providing the environmental services to protect the springs and riparian areas that lie within their properties. Twenty sampling stations were selected for collecting water samples monthly during the period July 2012 to June 2014 (460 samples) to evaluate the following variables: water temperature, pH, turbidity, dissolved oxygen, biochemical oxygen demand, nitrate, ammonia nitrogen, phosphate, total dissolved solids and thermotolerant coliforms. The evaluation was made based on decree 357/2005 of the National Environmental Council (CONAMA) and by applying the Water Quality Index (WQI). The results indicated a significant improvement in the water quality when comparisons were made between the periods before and after the installation of the preservation areas. The sampling points classified as “good” (CONAMA and WQI), which indicates water of good quality that is appropriate for multiple uses, increased from 52.0% to 72.0%. In this sense, promoting the preservation of headwaters and riparian zones becomes of fundamental importance and highlights the role of PES as an operational tool for water resource preservation.
This analysis applied systematic review as a methodology for identifying, analyzing and interpreting data on the use of water quality indices for human consumption. Scientific articles were searched in the “PubMed”, “Scielo”, “ScienceDirect” and “Web of Science" databases, using the keywords “drinking water” and “water quality index”, with a custom interval between 2000 and 2020. The results indicated 82,573 published articles, with 16 of them being selected after a filtering process. The occurrence of 11 water quality indices was verified, including 47 water quality parameters used to assess the quality of drinking water, highlighting that the parameters pH, Nitrate, Turbidity, Chloride and Sulfate were the most used, cited in 10 of the 16 articles selected (62,5%). We suggest that future studies seek to propose regionalized water quality indicators for consumption, in order to consider local aspects in the evaluation process and to determine intervention priorities by health surveillance agencies.
A ingestão de água com níveis elevados de flúor provoca uma patologia denominada fluorose dental, que resulta da mineralização defeituosa da matriz do esmalte, diretamente associada à quantidade de água ingerida de altas concentrações de fluoretos. Neste contexto, foi desenvolvido um sistema de desfluoretação por adsorção em carvão ativado de osso, seguido por precipitação por contato através da adição de sais de cálcio e fósforo. Este sistema foi construído em um tanque (filtro) de Poly Glass® com revestimento de polietileno transparente de alta densidade, preenchido com 25 kg de carvão ativado de osso de diâmetro de partícula igual a 20 x 50 mesh. Para o dimensionamento do sistema foi desenvolvido um software denominado Defluoridation, que permite a determinação das dimensões do sistema e as vazões de reagentes para o processo de precipitação por contato. O sistema foi aplicado no tratamento de água subterrânea com concentração de flúor entre 2,4 e 3,0 mg.L-1. No total, 30.000 L de água foram tratados, dos quais 13.000 L pela técnica de adsorção, e depois 7.000 L, que foram filtrados para atingir valores próximos da água bruta, e 10.000 L pela técnica de precipitação por contato. Os resultados obtidos demonstram a eficiência da aplicação do software Defluoridation, destacando que a técnica de precipitação por contato é uma forma econômica e simples para o fornecimento de água.
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