Assessment of Groundwater Quality from the Belém Based on Physicochemical Parameters and Levels of Trace Elements Using Multivariate Analysis

Abstract

Groundwater were sampled at 17 sampling locations of five districts of Belém City (Pará State, Brazil) in 2011, with objective of evaluate the quality of groundwater sampled in tubular wells potentially used for human consumption.For all groundwater samples were analyzed seven physicochemical parameters and nine trace elements determined by graphite furnace atomic absorption spectrometry (GF AAS).From these results and to better understand the physical and chemical behavior of these waters, multivariate methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to conduct a more thorough evaluation of the original data.The physicochemical parameters studied showed that the groundwater sampled in tubular wells from districts of Marco and Sacramenta had the highest total dissolved solids (140.0 to 244.5 mg L -1 ), electrical conductivity (198.3 to 340.2 µS cm -1 ) and turbidity (1.75 to 2.75 UNT) values, indicating the influence of anthropogenic activities contamination in the region, mainly related to the discharge of domestic effluents.In groundwater samples were found 10.4 to 460.5 µg L -1 Fe, 2.0 to 35.2 µg L -1 Cu, < LOD (0.08 µg L -1 ) to 0.68 µg L -1 Cd, < LOD (0.02 µg L -1 ) to 5.7 µg L -1 Cr, < LOD (0.01 µg L -1 ) to 2.3 µg L -1 Ni and < LOD (0.10 µg L -1 ) to 13.5 µg L -1 Pb.Furthermore, PCA explained 85.8% of the total variance, while the HCA confirmed the correlations found in PCA, allowing evaluating the degree of similarity between samples and identifying the districts most prone to groundwater contamination.