Study of the content of heavy metals related to environmental load in urban areas in Slovakia.

UNLABELLED It is natural for the man to take care of his environment so the negative influences of intensification of industrial and agricultural production and the entire process of pollution are kept at minimum or eliminated as early as possible. However, they must first be identified. BACKGROUND companion animals, for example dogs, are a very good indicator of the pollution load on the environment. They inhabit the same space as humans and are exposed to the action of the same pollutants. The most important role in contamination of the environment with heavy metals is played by emissions of different origin. For that reason it is appropriate and advantageous to evaluate the load on the man by parallel evaluation of the heavy metal load on dogs, particularly in large town agglomerations. MAIN PURPOSE the aim of the study was to compare and evaluate the content of three heavy metals, cadmium, arsenic and lead, in the hair of dogs from two largest town agglomerations of Slovakia, Bratislava and Kosice. In addition to that, an effort was made to compare the environmental load in Bratislava and Kosice by using the dog as a bioindicator of environmental pollution with heavy metals and to quantify the content of heavy metals in dog' hair. METHODS The generally low level of heavy metals in biological material makes it impossible to use common analytical methods. In our study the samples of dog hair were analysed using the method of atomic absorption spectrometry. The measurements were carried out on a Perkin-Elmer spectrometer, model 5000, using the following wavelengths: 228.8 nm for Cd, 193.7 nm for As and 283.3 nm for Pb. The results of analyses are presented as means. The concentrations of Cd, As and Pb are expressed in microg/kg dog hair. Statistical evaluation of results was carried out by means of Student's t-test. RESULTS The mean values of heavy metals in the set of dogs from Bratislava reached the following levels: 38.09 microg/kg for Cd, 111.07 microg/kg for As, and 729.59 microg/kg for Pb. The set of dogs from Kosice allowed us to detect the following mean values: 22.21 microg/kg for Cd, 79.87 microg/kg for As, and 542.49 microg/kg for Pb. The mean values for the entire Slovak territory reached 27.39 microg/kg for Cd, 90.06 microg/kg for As, and 601.96 microg/kg for Pb. The comparison of the first two experimental sets of data with the Slovak mean values showed highly significant differences in arithmetic means (p < 0.01) for Cd and significant (p < 0.05) for As with the Bratislava set reaching higher values. No statistically significant differences were observed with regard to Pb. CONCLUSION The study confirms the need for further research in this area with the dog as a bioindicator involving also other environmental loads not only that resulting from heavy metals. It indicates the importance of risk assessment in relation to environmental pollution. As the studies on animals are applicable also to the human population it appears very appropriate to use also this indirect way to point out to the negative impact of the polluted environment. Lead, cadmium and arsenic are the heavy metals that raise particular concern because of their wide-spectrum negative influences on live organisms. (Tab. 4, Fig. 5, Ref 28.)