Survey on Lead Contamination of Brown Rats (Rattus norvegicus) as a Bioindicator in Urban Areas of Golestan and Mazandaran Provinces

Heavy metals, such as lead harms animals’ health. The objective of this study was to evaluate the level of Pb pollution in the cities of Golestan and Mazandaran Provinces by measuring Pb concentrations in the blood of brown rats, which serve as omnivorous bioindicators living in the same habitat as humans.

Eight highly populated cities were selected, with 10 rats trapped in each city. Blood samples were taken from the rats, and Pb measurements were done by atomic absorption spectrometry.

All sampled rats were Pb-contaminated. The mean Pb concentrations in different cities of Golestan Province were statistically similar (p > 0.05). In Mazandaran cities, however, significant differences in mean Pb concentrations were observed. The highest contamination was recorded in Neka (10.28 ± 0.97 μg/dL), while the lowest contamination was observed in Babol (7.3 ± 1.36 μg/dL). The mean Pb concentrations in the studied cities of Golestan (9.43 ± 1.81 μg/dL) and Mazandaran (9.02 ± 1.07 μg /dL) Provinces, as well as in male (10.38 μg/dL) and female (9.25 μg/dL) rats were similar.

The Pb contaminations observed in the sampled rats are indicative of Pb contaminations of the sampled cities and the presence of Pb sources in these areas. It seems necessary to take precautionary procedures to prevent the entry of polluted effluents into the sampled cities and the consumption of Pb-contaminated gasoline in these areas, to prevent Pb contamination of human populations.