Revista Ambiente & Água (Apr 2022)

Assessment of water and sediment quality variation due to organic and conventionally irrigated pre-germinated rice-field cultivation

  • Enio Sebastião Vicente de Jesus,
  • Letícia Schönhofen Longoni,
  • Luciano Kayser Vargas,
  • Anelise Beneduzi

DOI
https://doi.org/10.4136/ambi-agua.2825
Journal volume & issue
Vol. 17, no. 2
pp. 1 – 16

Abstract

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This study evaluated the water and sediment quality of samples collected from different points in organic (O1, O2, O3, and O4) and conventional (C1, C2, and C3) pre-germinated rice fields located in Viamão/RS. Quality indicators such as phosphorus, dissolved oxygen, manganese, iron, turbidity, and BOD5 reduced water quality beyond Classes 3 and 4, as defined by CONAMA Resolution 357/2005. Based on the aluminum levels, the water samples collected from all the points were categorized as Class 4; furthermore, the IQA classified the quality of water samples from Points O4 and C1 as “bad.” The COD/BOD ratio was high, demonstrating that the biodegradable fraction was considerably low. The conductivity of water at points O4, C1, C2, and C3, exceeded 100 µS/cm, as defined by CETESB, indicating impacted environments. The levels of zinc in C1 and nickel in O2, C2, and C3 in the sediment exceeded the quality reference values established by the FEPAM Ordinance 85/2014. In general, the lowest water quality was observed in the samples collected from Points O2 and O4, and the lowest sediment quality was observed in the samples collected from all points in the conventional rice fields and from Point O2 in the organic rice field.

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