Science & Tech · Science & Environment · 6 hrs ago
Sunlight-aged microplastics can reduce toxic chromium, study finds
Scientists found that sunlight-aged polystyrene microplastics can reduce toxic chromium in laboratory experiments.
The research team was led by scientists at Northeast Normal University.
Chromium-6 can enter waterways through waste from metal-finishing plants and is more harmful and mobile than chromium-3.
The researchers exposed plastic particles to ultraviolet light for different lengths of time, then placed them in chromium solutions.
Particles aged for 96 hours reduced nearly 90 percent of the chromium-6, compared with 38 percent for fresh particles under ultraviolet light.
The change happened through reactions involving the plastic surface and chemicals released as it broke down.
The finding shows microplastics can affect water chemistry, but it does not mean plastic pollution is beneficial; the study leaves open how these reactions affect the environment.
A study found that polystyrene microplastics exposed to sunlight can convert toxic hexavalent chromium into the less harmful trivalent form.
Particles aged under ultraviolet light for 96 hours reduced nearly 90 percent of the hexavalent chromium in the experiments.
Fresh particles reduced 38 percent under ultraviolet light, while the reaction barely occurred without it.
The researchers identified two pathways: electron transfer from aged particle surfaces and reactions involving chemicals released by the plastic.
The researchers said the findings reveal an unexpected effect of microplastics on water chemistry, not a benefit of plastic pollution.
- Who
- Scientists at Northeast Normal University led the research; senior author Jiunian Guan was named.
- What
- The study found that sunlight-aged polystyrene microplastics can reduce hexavalent chromium to the less harmful trivalent form.
- When
- The article was published on 2026-11-02. The study date is not stated.
- Where
- The research was led by scientists at Northeast Normal University. The experiments’ location is not stated.
- Why
- The researchers investigated whether microplastics participate in the natural chemistry that converts hexavalent chromium into trivalent chromium.
This story does not have two clearly opposing sides.
The researchers aged polystyrene particles for different durations, including 0 hours, before testing them in chromium solutions.
Particles aged for 96 hours reduced nearly 90 percent of the hexavalent chromium in the experiments.
Earth.com published its article about the study.
- Research lead
- Scientists at Northeast Normal University
- Senior author
- Jiunian Guan
- Plastic tested
- Polystyrene microplastics
- Aging durations
- 0, 6, 12, 24, 48 and 96 hours under UV light
- Reduction after 96 hours
- Nearly 90 percent of hexavalent chromium
- Reduction by fresh particles
- 38 percent under UV irradiation
What people are saying
Our findings suggest that microplastics are not simply passive carriers of pollutants. As they age under light exposure, they can become chemically active participants in environmental processes
Understanding these reactions is important for evaluating how plastic pollution may alter