Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem
This study follows the geochemistry of nitrogen in a Cretaceous and unconfined sedimentary aquifer in the city of Urânia (Brazil) over 20 years. Although the sewer network was built in the 1970s, the nitrate contamination problem (>45 mg/L-NO<sub>3</sub><sup>−</sup>) persi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-09-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/12/10/2709 |
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| author | Ricardo Hirata Fabiana Cagnon Aline Bernice Carlos Henrique Maldaner Paulo Galvão Carlos Marques Rafael Terada Claudia Varnier M. Cathryn Ryan Reginaldo Bertolo |
| author_facet | Ricardo Hirata Fabiana Cagnon Aline Bernice Carlos Henrique Maldaner Paulo Galvão Carlos Marques Rafael Terada Claudia Varnier M. Cathryn Ryan Reginaldo Bertolo |
| author_sort | Ricardo Hirata |
| collection | DOAJ |
| description | This study follows the geochemistry of nitrogen in a Cretaceous and unconfined sedimentary aquifer in the city of Urânia (Brazil) over 20 years. Although the sewer network was built in the 1970s, the nitrate contamination problem (>45 mg/L-NO<sub>3</sub><sup>−</sup>) persists to this day. The oldest urbanization areas located in the north of the city initially used cesspits for wastewater and currently present the highest nitrate concentrations (>120 mg/L-NO<sub>3</sub><sup>−</sup>), with the plume reaching the deeper aquifer portions (up to 100 m). The contamination is not as dramatic in the south part of the city, where urbanization including installation of the sewage network with PVC pipes that are more resistant to leak than the old ceramic networks occurred after 1985. Based on the constructive well profiles, three hydrogeochemical zones were established: shallow (<20 m deep), with average nitrate of 63 mg/L-NO<sub>3</sub><sup>−</sup>; intermediate (20–60 m), with 30 mg/L-NO<sub>3</sub><sup>−</sup>; and deep (>60 m), with 17 mg/L-NO<sub>3</sub><sup>−</sup>. The current total nitrate mass in the aquifer exceeds 731 kg-NO<sub>3</sub><sup>−</sup>. Numerical flow (Modflow) and transport (MT3D) model scenarios support the hypothesis that the nitrate contamination is caused by substantial infiltration of nitrogen through the cesspits until the 1970s, but after the 1990s, leaks from the sewer network should be responsible for the maintenance of the recently observed high concentrations of nitrate. |
| first_indexed | 2024-03-10T16:00:58Z |
| format | Article |
| id | doaj.art-a07fbaab360b417181bb9b15a360027d |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T16:00:58Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-a07fbaab360b417181bb9b15a360027d2023-11-20T15:18:24ZengMDPI AGWater2073-44412020-09-011210270910.3390/w12102709Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious ProblemRicardo Hirata0Fabiana Cagnon1Aline Bernice2Carlos Henrique Maldaner3Paulo Galvão4Carlos Marques5Rafael Terada6Claudia Varnier7M. Cathryn Ryan8Reginaldo Bertolo9CEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilPampulha Campus, Department of Geology, Federal University of Minas Gerais, Belo Horizonte 31270-901, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilGeosciences Department, University of Calgary, Calgary, AB T2N 1N4, CanadaCEPAS|USP Groundwater Research Center, Institute of Geosciences, University of São Paulo, São Paulo 05508-080, BrazilThis study follows the geochemistry of nitrogen in a Cretaceous and unconfined sedimentary aquifer in the city of Urânia (Brazil) over 20 years. Although the sewer network was built in the 1970s, the nitrate contamination problem (>45 mg/L-NO<sub>3</sub><sup>−</sup>) persists to this day. The oldest urbanization areas located in the north of the city initially used cesspits for wastewater and currently present the highest nitrate concentrations (>120 mg/L-NO<sub>3</sub><sup>−</sup>), with the plume reaching the deeper aquifer portions (up to 100 m). The contamination is not as dramatic in the south part of the city, where urbanization including installation of the sewage network with PVC pipes that are more resistant to leak than the old ceramic networks occurred after 1985. Based on the constructive well profiles, three hydrogeochemical zones were established: shallow (<20 m deep), with average nitrate of 63 mg/L-NO<sub>3</sub><sup>−</sup>; intermediate (20–60 m), with 30 mg/L-NO<sub>3</sub><sup>−</sup>; and deep (>60 m), with 17 mg/L-NO<sub>3</sub><sup>−</sup>. The current total nitrate mass in the aquifer exceeds 731 kg-NO<sub>3</sub><sup>−</sup>. Numerical flow (Modflow) and transport (MT3D) model scenarios support the hypothesis that the nitrate contamination is caused by substantial infiltration of nitrogen through the cesspits until the 1970s, but after the 1990s, leaks from the sewer network should be responsible for the maintenance of the recently observed high concentrations of nitrate.https://www.mdpi.com/2073-4441/12/10/2709nitrategroundwater contaminationurban hydrogeologyurban aquifer recharge |
| spellingShingle | Ricardo Hirata Fabiana Cagnon Aline Bernice Carlos Henrique Maldaner Paulo Galvão Carlos Marques Rafael Terada Claudia Varnier M. Cathryn Ryan Reginaldo Bertolo Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem Water nitrate groundwater contamination urban hydrogeology urban aquifer recharge |
| title | Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem |
| title_full | Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem |
| title_fullStr | Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem |
| title_full_unstemmed | Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem |
| title_short | Nitrate Contamination in Brazilian Urban Aquifers: A Tenacious Problem |
| title_sort | nitrate contamination in brazilian urban aquifers a tenacious problem |
| topic | nitrate groundwater contamination urban hydrogeology urban aquifer recharge |
| url | https://www.mdpi.com/2073-4441/12/10/2709 |
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