Microplastics characteristics and environmental correlates of their presence in the nests of white stork: An evidence for biotransfer and biocirculation in the ecosystem

Plastic has become a widely used material over the past century. The continuous production of various products has created large amount of plastic waste, which, despite the recently introduced recycling processes, has entered the environment. The common presence of plastics has resulted in their progressive use by animals, leading to their transfer and circulation in the ecosystem. Numerous bird species started to use plastics as nesting material at an early stage of their emergence. However, most studies conducted to date have focused on coarse plastic debris, ignoring the problem of transfer and deposition of microplastics (MCs) in nests. The aim of our research was to determine the presence and characteristics of MCs deposited in the nests of White Stork Ciconia ciconia, an iconic farmland species. MCs were investigated using a Nicolet iN10 FTIR microscope in 47 nests material samples collected in NE Poland. On average 4.4 pieces kg−1 and 0.2 g kg−1 of MCs were recorded in nest material, with wide variety of types, sizes, shapes and colours. Polypropylene and polyethylene in the form of fibers and fragments dominated among detected MCs, with a notable share of < 1 mm debris. Our research indicates a significant relationship between the amounts of MCs deposited in nests and selected environmental characteristics, such as the land cover and farming type within a radius of 500 m and 2500 m around the nests. We revealed the positive relationships between the number or mass of MCs and percentage of meadows in the landscape and the density of cattle. The results define the need for educational campaigns for society and scientific research on biotransfer and biocirculation of plastic in the environment with special emphasis on the effects of MCs on ecosystem in general and farmland birds in particular.