[Anchor]

Every summer, Daecheong Lake suffers from severe algal blooms. Now, research has shown that this algae does more than just harm water quality; it also accelerates the release of microplastics that threaten our health.

TJB reporter Cho Hyeong-jun has the details.

[Reporter]

Plastic bottles float on the water's surface.

The water, murky as if green paint has been mixed in, even emits a foul odor.

At a glance, the water quality looks extremely poor, and scooping up the water in a transparent cup reveals green particles floating around.

Daecheong Lake, a drinking water source for the Chungcheong region, suffers from algal blooms every summer.

This happens because the lake has many winding sections where water flow is slow, and combined with heatwaves, it creates an environment favorable for harmful cyanobacteria to multiply.

Now, a research team at KAIST has revealed for the first time that algal blooms, previously regarded simply as water pollution, can trigger even more serious environmental contamination when they meet discarded plastics.

As a result of an experiment conducted by the research team by creating an artificial algal bloom environment for six weeks, plastics exposed to the algal environment had their surfaces oxidized faster and developed more micro-cracks than those in a normal environment.

In other words, algae makes plastics break apart more easily and accelerates the generation of microplastics.

[Kim Young-ju / Ph.D. student, Department of Civil and Environmental Engineering, KAIST: What we also found is that a specific microbial community, a type of microorganism capable of degrading plastics, thrives much more abundantly on the plastic surface.]

The cause is none other than microorganisms.

As plastics discarded in rivers or lakes age over time, various microorganisms attach to their surfaces, and when algal blooms occur, bacteria proliferate more rapidly, forming a thick layer on the plastic surface.

This biofilm accelerates the oxidation of the plastic surface and creates cracks, which speeds up the rate at which it decomposes into microplastics.

[Kim Young-ju / Ph.D. student, Department of Civil and Environmental Engineering, KAIST: Types of environmental pollution that might be considered somewhat separate, such as algal blooms and plastic pollution, can ultimately influence each other...]

This study demonstrates that the management of algal blooms and plastic waste are not separate tasks, and it is expected to serve as an important scientific basis for jointly promoting water quality management and waste plastic reduction policies in the future.

(Video by Kim Sung-soo / TJB, CG by Kim Yoon-jung / TJB, Photo courtesy of KAIST)

TJB, Cho Hyeong-jun