[en] High mercury levels in carnivorous fish at the Guri reservoir located at the southeastern of Venezuela in the State of Bolivar point toward the presence of a bioaccumulation process in this reservoir. It was necessary to identify and classify development unities in settlements nearby reservoir Guri according to their use, due to the lack of up-to-date demographic information. The total mercury concentration in 7 sediment samples from reservoir Guri ranged from 0.0281 to 0.0877 High mercury levels in carnivorous fish at the Guri reservoir located at the southeastern of Venezuela in the State of Bolivar point toward the presence of a bioaccumulation process in this reservoir. It was necessary to identify and classify development unities in settlements nearby reservoir Guri according to their use, due to the lack of up-to-date demographic information. The total mercury concentration in 7 sediment samples from reservoir Guri ranged from 0.0281 to 0.0877 μg/g while methyl mercury levels oscillated from 0.15 to 3.45 ng/g. A total of 33 fish samples were analyzed; in general, according to the remarks on mercury levels the values ranged from very low to high. Ninety seven percent of fish samples had total mercury concentrations below 0.5 μg/g which is the guideline recommended by World Health Organization for human consumption; however, it was found in a sample from the carnivorous trophic level a total mercury concentration of 3.56 μg/g (Hydrolicus scomberoides, common name 'Payara'). Ninety-eight hair samples were collected from the exposed group, the highest mean concentration of mercury was found in 'Los Guacos' (12.82 μg/g) and it was higher than the mean value of the non exposed group (1.62 μg/g; n = 23). A total of 28 cases of the exposed group had hair mercury concentrations above 6.0 μg/g. It was found significant difference between the exposed and non exposed groups (p= 0). A pre-impoundment sampling was carried out in the flood area of reservoir 'Caruachi'. Eighty-three soil samples were gathered for mercury analysis, the total mercury concentration ranged from 0.1 to 367 μg/g. There was a wide variability among samples; however, such high values may chiefly have some relationship to mining - intensive operations that were carried out in the area for more than 30 years. To analyze the spatial structure of mercury levels in soil a semi variance analysis was applied to confirm autocorrelation of the variable. It was found a well-localized gradient of mercury concentrations; however, mercury levels were spatially too disperse on a wide sector and punctual in others. (author)

[en] In the reservoir Guri located at the south of Venezuela in Bolivar State has occurred the bioaccumulation process. Several studies have demonstrated it. In samples of 42 specimens of carnivorous trophic level, the average value of total mercury was 1.90 mg/g with a maximum of 6.04 mg/g. As first job it was necessary to identify and classify the infrastructures of each town according to their use due to the lack of updated demographic information. In this investigation is described the home characteristics with relation to its residence conditions and work status of home bosses through the design and application of a survey by home in two communities nearby reservoir Guri: 'La Paragua' and 'El Manteco'. A simple questionnaire was also designed and applied where home bosses were asked for the weekly frequency of consumption of fish, especially those of carnivorous habits as well as the quantity in grams consumed per week. Homes were better structured at 'La Paragua' than at 'El Manteco' but in the latest the monthly income by home was bigger nevertheless, it does not meet the requirements of the basic basket in Venezuela of US $ 323 for a four people family. The overall consumption of fish per week was twice higher at 'El Manteco' (1,485 kg) than at 'La Paragua' (678 kg). The fish specie consumed as first priority at 'La Paragua' was Prochilodus rubrotaeniatus ('Coporo') which is of detritivorous alimentary habits while the second more consumed was Cichla ocellaris ('Pavon') of carnivorous alimentary habits. On the opposite side, at 'El Manteco' the first priority of fish was Cichla ocellaris ('Pavon') while the second one was for Prochilodus rubrotaeniatus ('Coporo'). Next step will be the organic mercury analysis in hair samples and the nutritional profile in individuals from the selected homes: 36 at 'La Paragua' and 50 at 'El Manteco' towns. (author)