CONTAMINANTES EMERGENTES EM ÁGUAS NATURAIS: DETERMINAÇÃO DE FÁRMACOS E HORMÔNIOS EMPREGANDO VOLTAMETRIA

Abstract

Emerging contaminants comprise a series of natural and synthetic chemical substances including pharmaceutical, and personal care products, pesticides, industrial products, and other. These substances are poorly studied. The analytical methods employing voltammetry for determination of psychotropic drug, alprazolam, and synthetic contraceptive, 17α-ethinylestradiol, in natural waters was developed. The experimental conditions of voltammetric analysis for each drug was optimized, such as supporting electrolyte, pH, dilution of the samples and voltammetric conditions. Cyclic voltammetry was used to determine the nature of the electrochemical process involved . The developed methods were validated through studies of linearity, sensitivity, limits of detection (LOD) and quantification (LOQ), accuracy, precision and selectivity. For alprazolam, limits of detection and quantification were 0.1 μg Lˉ¹ and 0.4 μg Lˉ¹, respectively. The relative standard deviation was below 10 % in the precision tests for alprazolam The recoveries ranged of 96 to116% for accuracy tests. The LOD and LOQ to 17α-ethinylestradiol were 0.5 μg Lˉ¹ and 1.6 μg Lˉ¹, respectively. The relative standard deviation was less than 15% in the tests of precision and the recoveries ranged of 90 to 106% for contraceptive. The drugs were determined in samples of natural water from rivers, and springs next to Guarapuava region, Paraná, Brazil. The samples were collected from the spring, the Carro Quebrado stream and upstream of Cascavel River. The concentrations determined in the samples were below the limit of detection for both drugs. The concentration of alprazolam determined in Cascavel River located in the in the downstream of municipal sewage treatment plant was 5.9 ± 0.5 μg Lˉ¹. The presence of alprazolam in the downstream of the Brazilian river showed that the sewage treatment processes was ineffective. It is known that psychoactive species cause behavioral changes in some aquatic organisms, but the effects of chronic exposure to psychoactive substances are poorly understood.