Researchers from Tokyo Metropolitan University have made a significant discovery regarding the relationship between microplastics, particularly polystyrene foam, and the transportation of heavy metals such as copper and chromium in Mongolia’s Tuul River. The study reveals that surface features, including holes and biofilms found on microplastics, contribute to the accumulation of these pollutants, raising concerns about potential environmental risks.
Crucial Insights: Spreading Pollution via Cracked Surfaces and Biofilms
A team of scientists led by Tokyo Metropolitan University investigated the accumulation of heavy metals by microplastics in the environment. As microplastics disperse, so does the toxic cargo they carry. By focusing on polystyrene foam, the researchers collected particles along the Ulaanbaatar River in Mongolia. They discovered significant levels of heavy metals adhering to the particles, reflecting local land use, industrial activities, and the presence of surface features like holes and biofilms that facilitate the collection of pollutants.
The Ecological Disaster of Plastic Debris and its Surprising Role as a Vector
The intrusion of plastic debris into natural environments poses an ecological disaster. Due to mismanagement, plastic waste enters both terrestrial and marine ecosystems, where it weathers and breaks down into increasingly smaller particles that are challenging to collect and separate. These lightweight, low-density, and resilient microplastics spread rapidly. While they are generally chemically inert, scientists have now found that they can also serve as effective carriers for absorbed substances, including hazardous pollutants. Extensive research is currently underway to determine the types of toxins they transport and the mechanisms involved.
Observing the Physical and Chemical Properties of Polystyrene Foam
Under the leadership of Dr. Batdulam Battulga, an affiliated researcher of the Department of Geography at Tokyo Metropolitan University, in collaboration with Professor Masayuki Kawahigashi, the team examined polystyrene foam particles collected from different locations along the Tuul River in Ulaanbaatar, Mongolia. The rapid urban development of the capital city has led to the omnipresence of plastic waste, particularly polystyrene foam used for insulation, in the environment. The researchers subjected these small fragments to various analyses to understand how they had changed and what substances they contained. They discovered a variety of metallic contaminants that were not present in the original material, with copper and chromium being predominant. Additionally, the team identified significant signals of metals associated with specific land uses and industries in the city, such as chemicals used in glass and ceramic production, as well as pollutants from wastewater treatment plants.
Examining Surface Properties and the Role of Biofilms
The researchers also conducted a detailed analysis of the physical properties of the particles themselves. Scanning electron microscopy (SEM) images revealed that exposure to the environment had significantly altered the surface properties of the particles, resulting in fractures, holes, and pits. Many images displayed mineral crystal particles, indicating that the roughened surface could absorb inorganic pollutants from the surroundings. Furthermore, the team found evidence of biofilms, bacterial layers that adhere to surfaces. These films develop electric charges and chemical groups on their surfaces, effectively absorbing metallic contaminants. Considering the stronger accumulation of metals in meso-sized particles (5-20mm) compared to micro-sized particles (<5mm), the researchers concluded that surface features played a pivotal role in the collection of heavy metals on plastic debris.
Unveiling the Impact of Plastic Pollutants and their Hidden Dangers
By gaining insights into the mechanisms through which metals adhere to plastic fragments, the team aims to comprehend the extent of the impact of plastic pollutants on our environment and the concealed hazards they may pose.
Reference: “Plastic-associated metal(loid)s in the urban river environments of Mongolia” by Batdulam Battulga, Mariko Atarashi-Andoh, Jun Koarashi, Bolormaa Oyuntsetseg, and Masayuki Kawahigashi, 6 June 2023, Ecotoxicology and Environmental Safety.
DOI: 10.1016/j.ecoenv.2023.115100
The research was supported by a Tokyo Metropolitan Government Advanced Research Grant (Grant Number R4-2).
Table of Contents
Frequently Asked Questions (FAQs) about microplastics
What did the researchers from Tokyo Metropolitan University discover?
The researchers discovered that microplastics, particularly polystyrene foam, in Mongolia’s Tuul River carry high levels of heavy metals like copper and chromium.
How do surface features on microplastics contribute to pollutant collection?
Surface features such as holes and biofilms on microplastics enhance the collection of pollutants, including heavy metals. These features provide surfaces for metals to adhere to, increasing their accumulation on the plastic particles.
What are the potential environmental risks associated with microplastics and heavy metals?
The accumulation of heavy metals on microplastics poses potential environmental risks. These pollutants, carried by microplastics, can have detrimental effects on ecosystems and organisms when they enter the environment.
What role do microplastics play in spreading pollution?
Microplastics act as vectors for spreading pollution. As microplastics disperse in the environment, they transport toxic substances, including heavy metals, to different locations, contributing to the contamination of ecosystems.
How do microplastics interact with the environment?
Microplastics, due to their small size and resilient nature, can easily enter terrestrial and marine environments. They weather and break down over time, becoming too small to be easily collected and separated. This allows them to spread rapidly and potentially interact with various organisms and habitats.
More about microplastics
- “Plastic-associated metal(loid)s in the urban river environments of Mongolia” (Research Paper): Link
- Tokyo Metropolitan University: Link
