Estudo da contaminação por bifenilas policloradas e parâmetros de qualidade do mel orgânico e do mel convencional do Rio Grande do Sul

Abstract

Honey gives an image of being natural, healthy and free from contaminants. In Brazil, Rio Grande do Sul is one of the states with the highest honey production. The great appreciation of this product, especially in the foreign market, requires the application of rigorous standards of quality and safety of honey, as well as the investment in organic production system. Polychlorinated biphenyls, from English Polychlorinated biphenyls (PCBs), are toxic synthetic organochlorine compounds that, despite having been banned from manufacturing and marketing for several years, due to their inappropriate disposal, have contaminated the environment and are still detected. In the present work, the identity and quality patterns and the contamination by PCBs in 90 honeys of different floral origins (monofloral and multifloral) from organic and conventional production systems from Rio Grande do Sul were analyzed. The occurrence of 11 congeners of polychlorinated biphenyls: PCBs 28, 52, 77, 81, 101, 118, 126, 138, 153, 169 and 180. Extraction was performed using the modified QuEChERS method (Quick, Easy, Cheap, Effective, Rugged and Safe) followed by chromatography gas with microelectron capture detector with detection limits of 5 ng g-1 and 10 ng g-1. The results showed the presence of 4 congeners in 15 samples of honey from 9 municipalities, confirming environmental contamination in southern Brazil. The maximum levels of concentration detected were 635 ng g-1 for PCB 28, 194 ng g-1 for PCB 101, 65 ng g- 1 for PCB 77 and 50 ng g-1 for PCB 81. Although this contamination in honey represents a low risk, it is a persistent organic pollutant, classified as proven carcinogenic for humans and animals. Among the contaminated samples, no significant differences were identified regarding the production system and floral origin. When analyzing the results of the identity and quality standards individually, the vast majority of honeys were within the limits defined by national and international legislation, which allows us to affirm that the honey produced in Rio Grande do Sul has good quality, a fact that shows the adoption of good beekeeping practices by state producers. Through the analysis of the main components it was possible to explain a large part of the variability between the parameters humidity, ash, electrical conductivity, pH, free acidity, total acidity, reducing sugars, apparent sucrose, diastatic activity and HMF of the honey according to the production system and the floral origin. The analysis by hierarchical grouping, classifying in groups using Euclidean distances, showed the differentiation of these 10 quality parameters of the samples.