Popular Science: Passerine birds as environmental pollution indicators

The research was focused on 13 cities with different air pollution across the Czech Republic, comprises blood and feather samples of 57 great tit from the 2010 early breeding season.

In every tissue, the concentration of heavy metals (lead Pb, cadmium Cd, copper Cu, chromium Cr) and the arsenic mettaloid were evaluated. The results were compared with PM₁₀ (including < 10 μm particles) air pollution levels in the previous year.

Great tit  (Parus major) can reveal the true nature of environmental pollution. Source: Wikimedia Commons, author: Paweł Kuźniar.

The concentrations of all analyzed elements were higher than the appropriate limits of detections with the highest concentration of copper and lead in both blood and feathers. After that, the metal concentrations in blood followed in the order cadmium, chromium and arsenic, in feather samples it was chromium, arsenic and cadmium.

Although the changes of external phenotypic traits were not significantly high and it was possible for individuals to be considered healthy by the phenotypic traits, the influence of the heavy metal concentration on blood composition changes was crucial.

The total red blood cell count has decreased and the composition of white blood cells has changed, indicating anaemia-like conditions.

PM₁₀ air pollution levels were highest in Bohumín from the Moravskoslezský region on the border with Poland, reflecting the highest average blood contamination of the sampled individuals as well. The average feather contamination has revealed different results, due to the role of long-term stress, e.g. lead concentrations were highest in Příbram, cadmium in Karviná, copper and chromium in Benešov and arsenic in Olomouc.

Despite the reduction of heavy metal emission contamination during the 1990s, the results of health-related physiological traits in the research of free-living bird species have revealed that there is still an influx of these harmful substances into the natural environment. As these substances are cumulative, their long-term exposure can lead to major impairments in the functioning of the body's life functions and to the development of diseases. These worrying results are a challenge for further research and analyses of the impact of pollution in urban areas on living organisms, including humans.

Bauerová, P., Vinklerová, J., Hraníček, J., Čorba, V., Vojtek, L., Svobodová, J., Vinkler, M. (2017): Associations of urban environmental pollution with health-related physiological traits in a free-living bird species. Science of the Total Environment, 601–602, s. 1556–1565.

Kateřina FRAINDOVÁ