Waterbirds such as seagulls can play an important role in the movement of pollutants. Plastics and other waste such as glass and textiles can be picked up in open landfills and then disposed of where they remain, usually in the form of regurgitated pellets.
The Plastic intake It is harmful to the health of birds and can be fatal, but this biovectorization, or movement of animals, can also cause broader ecological problems through the bioaccumulation of plastics in natural ecosystems.
One study focused on black-headed gulls (Larus fuscus), one of the most common winter waterbirds in Andalusia, has focused on the role of these animals in the spread of plastics in natural waters. The study, which is published in the journal Waste managementis part of the GuanoPlastic research project funded by the Junta de Andalucía.
In recent years, plastic accumulation in wetlands has received increasing attention
“Until now, studies on plastic in birds have focused on the marine environment and the role of waterbirds in lakes and other inland waters has been underestimated. “In recent years, plastic accumulation in wetlands has gained increasing attention,” he explains. Victor Martin VelezCSIC researcher who worked at EBD-CSIC at the time of the study and is currently a scientist at the Institute of Marine Sciences (ICM-CSIC).
For the investigation a Tracking 45 seagulls For seven years they used GPS devices installed at their breeding sites in the United Kingdom, the Netherlands and Belgium. The movement patterns were combined with bird counts in the Fuente de Piedra Lagoon in Málaga and dietary studies in which the contents of regurgitated pellets were analyzed to estimate the amount and type of plastic deposited by groups of up to twenty thousand seagulls. Individuals that overwintered in the lake.
Black gulls are a species that is particularly common in the nature reserve Stone fountain. Their numbers have increased since landfills were created in many parts of Andalusia, where these species regularly feed and ingest plastics and other waste mixed with organic waste. The Data collected via GPS show that they can fly up to 80 kilometers, as far as Córdoba, the distance that separates the nature reserve from some of the landfills visited.
Plastics, glass and textiles
According to the data collected, 86% of the pellets vomited in the lagoon contained plastics and 94% contained other waste such as glass and textiles. The research team used laboratory techniques such as plastic classification using Fourier transform infrared spectroscopy (FTIR) to develop a mathematical model of biovectorization.
It is the first detailed study of this biovectorization of waste by seagulls from open landfills to lakes anywhere in the world.
According to calculations, each winter is average 400 kilograms (kg) of plastic in the lake, with a peak value of 800 kg in winter 2019-2020, consisting of about 16 million plastic particles. The weight of non-plastic waste deposited in the lake is even greater. Polyethylene (54%), polypropylene (11.5%) and polystyrene (11.5%) were the main plastic polymers in the waste.
“Our study is the first detailed study of this biovectorization of waste by seagulls from open landfills to lakes anywhere in the world,” he explains. Andy Green, CSIC Research Professor at the Doñana Biological Station. “From what we can see, this is by far the largest source of plastics entering the Fuente de Piedra lagoon.” Once in the lagoon, it is likely that the plastic will remain there as there is no drainage , as it is endorheic, and ends up breaking down into microplastics that affect other animals, including flamingos.
Across Europe and many parts of the world, seagulls forage for food in landfills or other sources of human waste and then similarly rest in lakes and other wetlands. This study quantifies what is likely widespread problem for natural areas.
“When we throw away plastic, it is likely that some of it will be transported to wetlands by birds. This is also why we have to reduce the amount of plastic waste we generate,” explains the researcher.
Reference:
Martín-Vélez V. et al. “Leakage of plastic and other waste from landfills into a highly protected lake by wintering seagulls.” Waste management