ACCUMULATION OF HEAVY METALS IN BIRD’S EGGS IN VARIOUS TRANSFORMED AREAS OF POLTAVA REGION (UKRAINE)

Abstract

Background. Most heavy metals (HMs) enter the bodies of birds through food chains. The increase in sources of contamination raises the concentrations of HMs in the soil, leading to their greater absorption into bird tissues and accumulation in eggs. The concentrations of HMs can vary significantly between the eggshell and the contents of eggs in different species.
Materials and Methods. The study focused on the eggs of four passerine bird species in 2024. The analysis of HM content (Cd, Co, Cr, Mn, Fe, Cu, Zn, Pb, Ni) in the eggs was conducted using the atomic absorption method in the Laboratory of Instrumental Soil Research Methods, Standardization, and Metrology at the National Scientific Center ”O. N. Sokolovsky Institute of Soil Science and Agrochemistry”.
Results. The levels of HMs detected in the eggs of house martin, great tit, blackbird, and song thrush from technogenic (Poltava Mining and Processing Plant (PMPP)) and natural (Regional Landscape Park ”Nyzhniovorsklianskyi” (RLP) and Vakalivshchyna ravine complex (VAK)) areas indicate significant variability in their accumulation. Iron was the dominant element in all samples. In eggshells, iron ranged from 17.76±0.3 mg/kg (RLP) in the blackbird to 169.25±0.8 mg/kg (PMPP) in the song thrush. In egg contents, iron levels were consistently high across all samples, from 70.76±0.5 mg/kg (PMPP) in the great tit to 1107.8±2.51 mg/kg (RLP) in the house martin. Iron plays a crucial role in oxygen transport, storage, and utilization, which is essential for most enzymes and proteins during embryo development. Zinc levels were lower, ranging in eggshells from 1.55±0.26 mg/kg (RLP) in the blackbird to 27.58±0.89 mg/kg (RLP) in the song thrush. In egg contents, zinc levels showed less variation, from 9.19±0.2 mg/kg (PMPP) in the blackbird to 30.08±0.61 mg/kg (PMPP) in the great tit. Antioxidant properties of zinc strengthen the immune system and support metabolism. Manganese levels in eggshells ranged from 1.72±0.28 mg/kg (VAK) to 30.76±0.49 mg/kg (PMPP) in the great tit. In egg contents, manganese levels varied from 2.63±0.45 mg/kg (VAK) to 61.43±0.41 mg/kg (PMPP) in the great tit. Manganese compounds are less toxic than those of more common metals such as nickel and copper, but prolonged exposure may lead to reproductive dysfunction. A significant lead level (35.45±0.53 mg/kg) was detected in the egg contents of the blackbird (RLP), which could negatively affect embryo development. Such trace elements as chromium, copper, cadmium, cobalt, and nickel were detected in lower concentrations. The paper examines the influence of three factors on the content of heavy metals. Statistically significant interactions between the factors were identified, indicating the need for further research into the mechanisms of heavy metal accumulation and their environmental consequences.
Conclusion. The study confirmed that the level of heavy metals in bird eggs reflects the ecological state of the environment, allowing to assess the pollution of natural and man-made areas. Species and territorial features of the accumulation of Fe, Pb, Zn, Mn and other metals were identified suggesting the influence of the environment on their bioaccumulation. Three-factor analysis of variance showed that the main factors determining the concentrations of metals in eggs are environmental conditions and the habitat of birds. The results obtained emphasize the feasibility of using bird eggs as an effective tool for environmental monitoring.