The research aim was to evaluate the levels of contamination with fluorine compounds in selected tissues of laying hens kept in a free range system in Central Pomerania (Poland) in relation to the distance from contaminant emission sources. The study covered 60, randomly selected, two-year-old laying hens on 6 farms. Fluorine levels in tissues of laying hens were determined with the potentiometric method using an ion-selective electrode from ORION. The results for the tissues and organs, such as pectoral muscles, livers and breastbones, were investigated with an analysis of variance, the Tukey’s test and linear correlation coefficients. The analyses revealed a higher mean fluorine compound content in the pectoral muscles, livers and breastbones of laying hens in Zone 1, located 50 km to the west of the contaminant emission sources, than in Zone 2, situated between 80 and 100 km to the west of the pollution sources. Fluorine compound levels in the pectoral muscles of Zone 1 birds were almost twice as high in hens from experimental Zone 2 (respectively: 1.835 mg kg-1 of DM and 0.978 mg kg-1 of DM). A statistically significantly higher average content of fluorine compounds (4.92 mg kg-1 of DM) was found in the liver of laying hens in Zone 1, nearer to the sources of fluorine compounds emission compared to Zone 2 (3.34 mg kg-1 of DM). The mean fluorine compounds content in the breastbones of hens in Zone 1 was more than 4 times as high as the level of this element identified in the bones of hens kept in Zone 2 (respectively: 765 mg kg-1 of DM and 183 mg kg-1 of DM). A significant positive correlation was confirmed between fluorine compound levels in the breastbones and pectoral muscles. The lower level of fluorine compounds in the examined tissues of laying hens in Zone 2 could have been influenced by the dominant west and south wind, which limited the spread of pollution. This may also be due to the lower level of fluorine compounds in soil and feed for laying hens in this zone determined in previous studies. The study showed that the closer the sources of emissions of fluorine compounds, the more fluoride in hard tissues of hens’ bodies.  

26.1.2021