Methanol reference values in urine from inhabitants of Brazil.

In order to properly evaluate the results of the occupational biomonitoring of chemicals it is necessary to establish reference values for the biomarkers of exposure. The aim of this study was to determine the reference values for methanol in urine of the general population non-occupationally exposed to the xenobiotic under study. Thus, urinary methanol was measured in 84 occupationally non-exposed subjects from the city of São Paulo, Brazil, by means of headspace gas chromatography with a flame ionization detector. The results revealed a mean of 2.26 +/- 1.26 mg methanol/l urine and a geometric mean of 2.10 mg/l for the studied population. The reference values varied within the range of 0.50-4.78 mg/l (mean +/- 2 S.D.). Methanol levels in urine did not differ statistically between male and female subjects. Urinary methanol in the total population was less than 4.80 mg/l in 95% of cases.

[Determination of total mercury in water samples, sediments and solids in suspension in aquatic systems by cold-vapor atomic absorption spectrophotometry]. / Determinação de mercúrio total em amostras de água, sedimento e sólidos em suspensão de corpos aquáticos por espectrofotometria de absorção atômica com gerador de vapor a frio.

The use of metallic mercury in the extraction and concentration of gold causes the discarding of tons of this metal in the environment, leading to a considerable increase in the natural levels of the same and the contamination of the surrounding areas. Thus it is extremely important to monitor the presence of this metal in various sectors of the environment with a view aiming to preventing human exposure to excessive concentrations which can result in serious episodes of mercury poisoning. It is also important to estimate the possibility of river sediments becoming potential sources of contamination of human beings. The determination of total mercury was undertaken by using cold vapor atomic absorption spectrometry. River waters, as well as sediments and suspended solids were used as samples for the standardization of the analytical procedure. Later on, this method was tested on samples originating in gold mining areas for the purpose of assessing its validity.