Metals and dissolved organic carbon (DOC) of surface waters in two adjacent watersheds in the eastern Amazon

  • Juliana Feitosa Felizzola Laboratório de Análises de Sistemas Sustentáveis (LASS). Embrapa Amazônia Oriental (EMBRAPA), Travessa Dr. Enéas Pinheiro, s/n, Caixa Postal 48, CEP: 66.095-100, Belém, PA, Brazil
  • Anthony D. Cak Environmental Sciences Initiative, Advanced Science Research Center at The Graduate Center. The City University Of New York (CUNY), 85St, CEP: 10031, NY, United States.
  • Ricardo de Oliveira Figueiredo Embrapa Meio Ambiente, Rodovia SP-340, Km 127,5, CEP: 13918-110, Jaguariúna, SP, Brazil.
  • Marcelo de Oliveira Lima Instituto Evandro Chagas (IEC). Seção Meio Ambiente. Embrapa Meio Ambiente (EMBRAPA), Rodovia BR-316, km 7, s/n, CEP: 67030-000, Ananindeua, PA, Brazil.
Keywords: amazon basin, stream, water quality.

Abstract

 

Land-use intensification in the "Zona Bragantina" region, an area in the eastern Brazilian Amazon, has accelerated landscape changes from primary forest to a mixture of different land uses: native forest (riparian vegetation), secondary forest, pasture, annual cropland, perennial cropland, bare soil and fallow vegetation, with negative consequences for the stability and equilibrium of river systems. This study examined the temporal and spatial variation of dissolved organic carbon (DOC) and metal concentrations in stream water of the Cumaru (ICU) and São João (ISJ) watersheds from May 2014 to April 2015, to understand the chemical changes in forests and agro-ecosystems during one year. In both watersheds, higher concentrations of dissolved metals (aluminum, sodium, barium, calcium, iron, potassium, magnesium, copper and zinc) and DOC were measured in the rainy season, with considerable variability due to precipitation events. Furthermore, strong spatial variation was observed, with lower conductivity, higher pH, and higher concentrations of DOC and dissolved metals in the downstream reaches, especially for DOC in a small reservoir below a dam in ISJ. Significant human intervention was located in these downstream areas, including nearby agriculture and pasture, and use of stream resources for domestic activity. Sandy soil in these areas likely facilitated leachate processes, mainly in deforested areas, supporting the increased movement of metals from the land to the stream.


Author Biographies

Juliana Feitosa Felizzola, Laboratório de Análises de Sistemas Sustentáveis (LASS). Embrapa Amazônia Oriental (EMBRAPA), Travessa Dr. Enéas Pinheiro, s/n, Caixa Postal 48, CEP: 66.095-100, Belém, PA, Brazil
      
Anthony D. Cak, Environmental Sciences Initiative, Advanced Science Research Center at The Graduate Center. The City University Of New York (CUNY), 85St, CEP: 10031, NY, United States.
     
Ricardo de Oliveira Figueiredo, Embrapa Meio Ambiente, Rodovia SP-340, Km 127,5, CEP: 13918-110, Jaguariúna, SP, Brazil.
    
Marcelo de Oliveira Lima, Instituto Evandro Chagas (IEC). Seção Meio Ambiente. Embrapa Meio Ambiente (EMBRAPA), Rodovia BR-316, km 7, s/n, CEP: 67030-000, Ananindeua, PA, Brazil.
   
Published
11/11/2019
Section
Papers