Trace Elements in Indian Peafowl (Pavo cristatus): Exposure Routes

Abstract

Urbanization leads to chemical pollution. Contaminants accumulate in feed and enter animal body through digestive tract. Numerous studies have established that the level of mineral content in the environment reflects the technogenic load on the territory and is transmitted in the system through products of plant and animal origin, which can be used to prevent and correct elementoses.
 This research featured feathers of Indian peafowls Pavo cristatus (n = 33), diet components (n = 303), their drinking water (n = 94), soil (n = 123), and snow (n = 204). The micro-elemental profile was defined using an atomic absorption spectrometer. The samples were obtained from zoological institutions of Mosco w, Ivanovo, and Yaroslavl. 
 As for the feathers, the average Zn accumulation level was 122.74 ± 9.64 mg/kg, Cu – 5.36 ± 0.05 mg/kg, Fe – 508.06 ± 56.84 mg/kg, Pb – 6.75 ± 1.13 mg/kg, Cd – 1.65 ± 0.26 mg/kg, and As – 0.61 ± 0.23 mg/kg. The variability of the concentration of microelements in the sample was as follows, %: Zn – 73.9, Cu – 94.3, Fe – 111.6, Pb – 150.0, Cd – 136.88, and As – 203.87. The average levels of accumulation of elements in the biological media decreased in the following order: Fe > Zn > Cu > Pb > Cd > As. The share of Zn in the total of all determined elements was 0.7–48.0%, Cu – 0.04–2.8%, Fe – 46.2–92.8%, Pb – 0–2.5%, Cd – 0–2.5%, and As – 0–4.6%. The diet analyses showed the following results for Moscow, Ivanovo, and Yaroslavl, respectively: Zn – 11.35, 6.60, and 2.50 mg; Cu – 2.29, 0.75, and 0.41 mg; Fe – 55.83, 30.54, and 6.78 mg; Pb – 0.14, 0.18, and 0.01 mg; Cd – 0.02, 0.01, and 0.005 mg; As – 0.04, 0.02, and 0.002 mg. If the birds consumed all the food they received, the approximate total daily intake of the selected essential microelements Zn was 16.7–75.7% of the recommended daily intake, Cu – 13.7–76.3%, and Fe – 48.4–398.79%. Pb, Cd and As stayed within the daily norm. The oral route of intake was registered for Zn, Cu, and Fe in Yaroslavl and for Cd in all samples. Inhalation was registered as the main route of intake for Fe in Moscow and Ivanovo, as well as for As and Pb in Moscow. The highest intake of Pb was registered in Ivanovo and Yaroslavl.
 The analysis revealed the multi-route and multi-environment exposure of urban birds to microelements, including heavy metals. The level of concentration of essential microelements in the biological media depended on the diet. Fe in Moscow and Ivanovo and As in all the samples came from the soil cover, which had a high content of these elements. The gross content of Pb in the soil samples from Moscow and the drinking water from Yaroslavl and Ivanovo demonstrated the greatest impact on the avian organism. The snow samples had the least effect on the el emental status of the bioenvironments.