Nitrate Contamination in Brazilian Urban Aquifers: a Tenacious Problem
Carregando...
Data
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Minas Gerais
Descrição
Tipo
Artigo de periódico
Título alternativo
Primeiro orientador
Membros da banca
Resumo
ThisstudyfollowsthegeochemistryofnitrogeninaCretaceousandunconfinedsedimentary aquiferinthecityofUrânia(Brazil)over20years. Althoughthesewernetworkwasbuiltinthe1970s, thenitratecontaminationproblem(>45mg/L-NO3−)persiststothisday. Theoldesturbanizationareas locatedinthenorthofthecityinitiallyusedcesspitsforwastewaterandcurrentlypresentthehighest nitrateconcentrations(>120mg/L-NO3−),withtheplumereachingthedeeperaquiferportions(upto 100m). Thecontaminationisnotasdramaticinthesouthpartofthecity,whereurbanizationincluding installationofthesewagenetworkwithPVCpipesthataremoreresistanttoleakthantheoldceramic 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-NO3−; intermediate (20–60 m), with 30 mg/L-NO3−; and deep (>60 m), with 17 mg/L-NO3−. The current total nitrate mass in the aquifer exceeds 731 kg-NO3−. 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.
Abstract
Assunto
Recursos hídricos, Caracterização hidrogeológica
Palavras-chave
Nitrate, Groundwater contamination, Urban hydrogeology, Urban aquifer recharge
Citação
Departamento
Curso
Endereço externo
http://https://www.mdpi.com/2073-4441/12/10/2709/htmdoi:10.3390/w1210270