Cyanogenic Compounds, Physicochemical Parameters and Metals in Water From Cassava Processing Areas: A Study in the Brazilian Amazon, Using Multivariate Analysis.

This study evaluated the water quality of artesian wells and effluents generated in cassava processing in a rural area of Bragança, Pará, with emphasis on physicochemical parameters, multielement composition, and cyanogenic compounds. The well water presented specific nonconformities, highlighting pH values below the recommended level and high concentrations of residual chlorine. Although cyanide was not detected in the groundwater, the effluents presented concentrations of total and free cyanide above legal limits, mainly in the pressing water and in the washing and fermentation tanks, indicating an environmental risk associated with the inadequate disposal of these residues. Regarding the multielement analysis, boron and copper enrichment was observed in the well water, and high concentrations of manganese and nickel were found in the effluents, exceeding the limits established by Brazilian environmental legislation. The multivariate analysis revealed distinct physicochemical profiles between the well water and the effluents, with temperature, dissolved oxygen, and pH being the main factors responsible for the differentiation between the matrices. The results indicate the need for improvements in the management and treatment systems of cassava processing effluents, aiming at protecting water resources and reducing potential environmental and human health risks.