Using house sparrow in biomonitoring lead in Tehran air pollution

Urbanization is spreading all over the world, with more than half of the people now living in urban ecosystems. Pollutants such as metals have continuously been introduced into ecosystems as a consequence of urbanization and industrial processes. Metals can bioaccumulate in tissues of organisms. Therefore, the selection of ecological compartments such as birds as bio-indicator species can be a proper approach to monitor pollution in cities. This study aimed to measure concentrations of lead in the lungs and feathers of the house sparrow ( Passer domesticus ) and investigate the possibility of applying this species for air pollution monitoring in Tehran, Iran. In July and August of 2020, 50 bird specimens were collected from five regions of Tehran (north, south, east, west, and central) and 10 birds from Alborz region (as the control station). The lead concentration was measured by using a FAAS instrument after acid digestion. The results showed that the average lead concentration in feathers of five regions of Tehran (North: 42.95 ± 23.57, Central: 43.59 ± 9.58, South: 35.42 ± 3.38, East: 22.91 ± 3.24, and West: 34.36 ± 11.98 µg/g) were higher than those of the control station (14.40 ± 2.97 µg/g). Significant differences were observed between lead concentration in feathers of the birds collected from the control station and those of central, south and west of Tehran. Lead concentration in the birds’ lungs in all regions of Tehran (North: 72.65 ± 17.55, Central: 20.76 ± 3.02, East: 17.88 ± 1.74, and West: 30.19 ± 13.04 µg/g) except south (13.17 ± 2.14 µg/g) were higher than the control group (14.57 ± 1.94 µg/g). However, this difference was only significant between the birds of the control station and those of north of Tehran. In this study, no significant differences were observed between lead concentrations in male and female as well as adult and juvenile sparrows. Also, no significant correlation was observed between tissue accumulation of lead in feathers and lungs. This study suggests that feathers can be used as a useful indicator of local air pollution.