Banca de DEFESA: MICHAEL LIMA OLIVEIRA

Toxicological assessment, chemical elements, natural waters, soils, Xique-Xique City.

This work aimed to evaluate the levels of chemical elements in water and soil samples collected in the city of Xique-Xique, located in a region with high iron content in the center-north of Bahia, Brazil. The environmental assessment was established in five studies: (i) development of a portable prototype using digital colorimetry to determine total iron in natural waters; (ii) analysis of inorganic iron speciation in water samples; (III) determination of inorganic species in water and soil samples using inductively coupled plasma optical emission spectrometry (ICP OES); (iv) determination of lead and cadmium in water samples using electrothermal atomization atomic absorption spectrometry (ETAAS); (v) Toxicological assessment of the investigated soils using geochemical and ecological indices. The analytical methods were optimized using a two-level full factorial design, Box Behnken design, and the Doehlert matrix. All methods used were exhaustively validated by IUPAC recommendations. Analytical data were determined for the arsenic, calcium, chromium, copper, iron, potassium, magnesium, manganese, sodium, lead, sulfur, and cadmium elements in the matrices studied. The toxicological assessment was carried out using the following risk indices: ecological risk index (ERI), ecological potential index (PERI), non-carcinogenic risk (HI), contamination factor (CF), polluted load index (PLI), degree of contamination (Cdeg) and modified contamination factor (mCdeg) and the geochemical index (Igeo). The results of this assessment varied with the elements and soil samples investigated.