Ingestão diária estimada de bifenilos policlorados a partir de queijo por universitários em Santa Maria - RS

Abstract

Foodstuffs free of toxic substances are a continuous concern, for food industry, educational and research institutes, and mainly for consumers. Polychlorinated biphenyls (PCBs) are industrial organochlorine substances used in electrical transformers and capacitors oil. Due to the inappropriate discharge, PCBs contaminate the environment and enter in the food chain, which constitutes main source for human contamination. Man, that is in the top of food chain, receives the higher levels of these compounds. The concern about PCBs is centered on its toxicological potential, mainly as cancer inductors. Thus, the present master dissertation is aimed at investigating PCBs residues in cheese and estimating the daily intake of these compounds from cheese. To investigate the intake of cheese and other animal food products by university students in Santa Maria, RS, a food consumption frequency questionnaire was used. It was observed that all surveyed students consume animal food products. Industrialized cheese intake was 99 g/week and homemade cheese was 22 g/week. To evaluate the levels of PCBs 10, 28, 52, 153, 138 and 180 in cheese produced in Rio Grande do Sul State; cheese fat was extracted using sodium sulfate and petroleum ether. PCBs clean-up was performed using florisil and hexane. The identification and quantification was made by a gas chromatography with microelectron capture detector (GC-μECD). PCBs were found in 94.7% of analyzed samples, in an average concentration of 30.84 ng/g fat (range 0.00 to 78.32 ng/g fat). The congener found at the highest concentration was PCB 52 (15.75 ng/g fat). Differences in PCB levels between industrialized (33.32 ng/g fat) and homemade (26.58 ng/g) cheese were not statistically significant (p>0.05). Similarly, no statistical difference was observed among the three regions evaluated: Mountain/Porto Alegre (36.21 ng/g fat); Santa Maria (27.64 ng/g) and South/ Western (26.61 ng/g). All samples evaluated exhibited contamination below the maximum PCB level allowed in European Community for dairy products (100 ng/g fat). Based on cheese consumption by university students, the estimated daily intake (EDI) of PCBs was 1.74 pg/kg body weight for industrialized cheese and 0.34 pg/kg for homemade cheese. The EDI is below the tolerable daily intake established by World Health Organization, that amounts 4% of IDT to homemade cheese and 22% of IDT to industrialized cheese, concluding that the cheese produced in Rio Grande do Sul not offer toxicological risk under the evaluated aspect.