DISTRIBUTION OF TRACE-ELEMENTS IN EGG SAMPLES COLLECTED NEAR COAL POWER-PLANTS

The intensive nse of mineral coal for thermal power generation is know n to cause severe damage to the regional environment. The emission of cadmium (Cd), lead (Pb), and fluoride (F) compounds into the atmospher e may lead, under certain conditions, to serious contamination of prim ary matrices in the biosphere and even of foodstuffs. In the present s tudy, egg samples were collected from nonconfined hens (Gallus domesti cus) over a period of 2 yr in the vicinity of two of the major coal po wer plants (Candiota and Charqueadas) in the state of Rio Grande do Su l (RS), Brazil. The constituent parts of the samples (yolk, albumen, a nd shell) were solubilized with acid in a tenon-lined pressurized bomb after an appropriate heating step. The Cd and Pb were determined by g raphite furnace atomic absorption spectrometry using Pd/Mg nitric solu tion as chemical modifier. Fluoride was determined by direct ion-selec tive electrode potentiometry. Cadmium concentration in the samples fro m both regions ranged from <0.01 (albumen) to 0.10 (yolk) mg kg(-1) wh ereas Pb and F concentrations ranged from 0.16 (shell) to 3.16 (yolk) and from 0.06 (yolk) to 1.75 (shell) mg kg(-1) respectively. A compari son with the higher obtained mean values for reference samples (Cd < 0 .02 mg kg(-1), shell; Pb = 0.11 mg kg(-1), yolk; and F = 0.07 mg kg(-1 ), shell) indicates a significant environmental contamination with Pb and F in the regions of Candiota and Charqueadas. A relative Cd and Pb enrichment in the yolk was also confirmed, whereas F preferentially c oncentrated in the shell.