Mapping of Nitrate Contamination (NO3-) in an Urban Area on the Brazil/Bolivia Border

Abstract

: The objective of this research was to map and evaluate nitrate contamination in an urban area on the Brazil / Bolivia border. The evaluation of the groundwater table occurred in the water of cacimbas wells or Amazonian wells with an average depth of 10 meters in the city of Nova Mamoré, in the State of Rondônia, located in the southern region of Western Amazonia bordering the Republic of Bolivia. METHODS: Eighty (80) water samples were collected in the city's urban center, defined and evaluated for nitrate (NO3-) in a proportion above or below the values defined by Ministry of Health Ordinance No. 2.914/2011, which governs standards of water standardization and potability in Brazil. From the data obtained, maps with georeferenced information were made to locate the areas with the highest and lowest contamination potential. The use of geostatistics assisted in the accomplishment of the spatialization of the samples and in the analysis of the spatial patterns allowing a higher quality of the generated data. Results: Sixty-two and a half percent (62.5%) of the samples presented nitrate levels above 10 mg/L, making it unfit for human consumption. Conclusions: This study indicated that the source of the contamination originates from the result of anthropogenic activities, evidenced by the inefficiency of the sanitary sewage system, one of the basic sanitation axes in which, specifically, it addresses the collection, treatment and adequate disposal of sanitary sewage and other hygiene practices. It is necessary, the urgent insertion of public policies in the sector of basic sanitation in Nova Mamoré and in the Amazonian cities.