EN
The investigations aimed at the assessment of nickel contamination of the environment based on the content of this element in the coat of domestic and feral cats. The content of nickel in the coat was determined using the method ICP-OES. While assessing the state of nickel supply, a trial was undertaken at checking whether the increase in nickel content in the animal organism affects biological and haematological indexes of the animal. Blood plasma alkaline phosphatase, and alanine and aspartate aminotransferase (transaminase) activities, and haematological parameters were analysed. Then, the correlations between those indexes and the nickel content in cats' hair depending on cats' keeping (feral and domestic cats) and their sex were calculated. No statistically significant differences were noted depending on the cats living conditions. The obtained mean value of nickel content in the coat could be accepted as normal for cats. In the case of nickel, the differences depending on sex and age were also not significant statistically. The assessment of statistical indexes shows that median, similarly as lower quartile, are identical for the nickel content in the cats from both groups (0.40 mg·kg⁻¹) independently from their sex and age. Analysis of nickel content depending on hair colour was also performed assuming that the colour depends on the saturation of hair with melanin. The lowest nickel content was observed in white hair, higher in tortoiseshell hair and black hair, and the highest in the feral colour - brownish grey. The results confirmed the fact that the content of nickel depends on the hair saturation with melanin.