Inefficacy of cooking methods on mercury reduction from shark.

Shark and other carnivorous fishes present high potential risk of excessive contamination by mercury. The distribution of mercury throughout the body of blue shark--Prionace glauca--was analysed, and the effects on mercury levels by frying and baking in a laboratory oven, and in a microwave oven, were measured. There was no significant statistical difference in mercury levels in the samples taken from regions near the head, or from central and tail parts, indicating homogeneous distribution of the metal in muscles throughout the body. Frying and baking did not affect original mercury levels present in blue shark. This study indicates that specific studies are needed to define the efficacy or inefficacy of the cooking methods on mercury reduction from fish, in order to clearly resolve divergent opinions in the literature.

[Evaluation of lead and cadmium levels in milk in environmental contamination in the Vale do Paraíba Region, southeastern Brazil]. / Avaliação dos níveis de chumbo e cádmio em leite em decorrência de contaminação ambiental na região do vale do Paraíba, Sudeste do Brasil.

INTRODUCTION: A factory producing lead ingots, located in Caçapava, caused lead and cadmium contamination of the environment, in the Paraiba Valley region of Southeastern, Brazil, through the discharge of industrial waste and the recycling of batteries. The factory, set in a rural, dairy cattle breeding area, worried sanitary authorities who envisaged the possibility of these metals' having entered the food chain. For the purpose of assessing the levels of contamination of the milk produced in the region, due to the cattle's possible consumption of contaminated grass and water, the amounts of cadmium and lead present in the milk were verified. MATERIAL AND METHOD: Major producers, covering an area of up to 20 km from the contaminated source, authorized collection of 218 samples of both pasteurized and non-pasteurized milk, which were analysed. Lead and cadmium levels were determined by flame atomic absorption spectrophotometry, the lead being pre-concentrated by complexation with APDC (ammonium 1-pyrrolidinecarbodithioate) and further extraction with isobutyl methylketone. RESULTS AND CONCLUSIONS: Of the total number of samples, 43 presented lead levels over the maximum limit of 0.05 mg/kg established by Brazilian legislation. The median value found for lead was 0.04 mg/L. The variance analysis, with 95% confidence level, found no significant difference among the types of milk studied with regard to lead levels. As for cadmium, all samples showed levels below the 0.02 mg/L quantification limit of the method. In spite of the environmental contamination, the levels of cadmium found in the milk were below the 1.0 mg/kg limit established by Brazilian legislation.

[Mercury content in bleaches sold in the southeastern region of Brazil]. / Determinação de mercúrio em águas sanitárias comercializadas em região do sudeste do Brasil.

In order to determine the mercury content present as a contaminant in samples of bleach used in water and food disinfection, a method for sample treatment using chloridric acid to eliminate the chlorine was proposed. The technique of cold vapour atomic absorption spectrophotometry, used to quantify the mercury, showed a recovery of 103%. Sixty nine samples of bleach were analysed and the values found for the median and 90th percentil were respectively, 15 and 67 micrograms/L. According to the values of residual mercury found and using the quantities of bleach recommended by the Brazilian Sanitary Authorities, the use of these disinfectants offers no risk to human health.

[Levels of lead and mercury in the hair of children living in Cubatão, in the southeast region of Brazil]. / Teores de chumbo e mercúrio em cabelo de crianças residentes em Cubatão, na região sudeste do Brasil.

A study was carried out in 6 districts of Cubatão county, S. Paulo State, Brazil on a sample of 251 children aged between 1 and 10. The concentration of heavy metals (lead and mercury) in hair was tested. The lead concentration in the hair of 229 children was tested, and in 189 (82.5%) levels varying from 2.5 to 71.4 micrograms/g were detected. The average concentration of the lead found in hair was of 7.25 +/- 8.51 micrograms/g. The concentration of mercury in the hair of 217 children was checked and all of them were found to have levels varying from 0.2 to 3.0 micrograms/g. The average concentration of mercury was of 0.82 +/- 0.48 microgram/g. No statistical difference (p > 0.05) was observed between the averages found for lead and mercury in the hair of those who consumed and those who did not consume aquatic organisms.

[Heavy metal and organochlorine pesticide blood levels in children of 1 to 10 years of age]. / Concentrações sangüíneas de metais pesados e praguicidas organoclorados em crianças de 1 a 10 anos.

A study of a sample of 251 children aged between 1 and 10 was carried out in 6 districts of Cubatão county, S. Paulo State, Brazil. This study showed the presence of organochlorine pesticides in the blood serum of 242 children. p-p' DDE was detected in 73 of the samples (30%) and HCH in 47 of them (19%). The mean value of p-p' DDE was 0.85 +/- 2.13 micrograms/l. and that of HCH was 0.28 +/- 0.79 micrograms/l. Lead and mercury were also detected in the blood serum. The mean value for lead was 17.8 +/- 5.8 micrograms/l. and for mercury was 9.1 +/- 0.79 micrograms/l. The levels found in consumers of aquatic organisms taken from the rivers of Cubatão showed a mean mercury level (mean = 14.7 +/- 7.1 micrograms/l.) higher than (p < 0.04) that of those who did not consume any aquatic organisms at all (mean = 10.0 +/- 6.5 micrograms/l.).