Researchers Have Found a Simple Method of Assessment in Microplastic Concentration to Urban Rivers

Contamination with microplastic (MP) is a problem on a global scale. Even so, there is no accepted method for determining MP concentrations in rivers, which are where most MPs enter the ocean.

This results in arbitrary sampling and incorrect evaluations.

The right number of samples should now be taken to accurately measure the concentration of MP in freshwater, according to a method that researchers have recently proposed.

The technique could significantly cut down on the time and resources needed for MP surveys.

Improvement of microplastic concentration

(Photo : Sören Funk/Unsplash)

In a recent study that was published in the journal Environmental Pollution, Dr. Mamoru Tanaka, Professor Yasuo Nihei, Associate Professor Tomoya Kataoka, and others from Tokyo University of Science and Ehime University, Japan, improved the estimation of the MP concentration by taking the variability in estimations from various samples into account, as per ScienceDaily.

The variance can be used to calculate the number of samples that should be taken to accurately represent MP contamination.

According to Dr. Tanaka, they have proposed a procedure for determining the right amount of iterations in each contamination situation for an on-site sampling of microplastics.

The variance can also reveal information about the distribution of MPs within the waterbody.

The variances between samples, for instance, would be minimal if they were evenly distributed throughout the river.

On the other hand, a high variance would suggest a clumped distribution that is not uniform.

The researchers used a different technique meant for zooplankton to assess the inter-sample variances in MP concentration.

Most importantly, the team discovered that two replicate samples are adequate at high MP concentrations to accurately measure the MP concentrations.

In conditions with high concentrations of much more than 3 particles/m3, they discovered that the mean of two replicates retained sufficient precision of less than 30%, according to Dr. Tanaka.

Also Read: Microplastic Pollution: California State Government Adopts Strategy of Microplastic Cleanup

Possible harm of microplastics

Although the majority of studies have concentrated on the risks to marine life, scientists have been concerned about the potential harms of microplastics for almost 20 years, as per Nature.

The term was created in 2004 by marine ecologist Richard Thompson of the University of Plymouth in the UK to describe plastic fragments that were smaller than 5 millimeters after his team discovered them on British beaches.

Since then, scientists have discovered microplastics everywhere they have looked: in the deep oceans, in the snow and ice of the Arctic and Antarctic, in shellfish, table salt, water, beer, and in the air or in the rain that falls over mountains and cities.

The full degradation of these tiny pieces might take decades or longer.

According to Tamara Galloway, an ecotoxicologist at the University of Exeter, UK, almost all species probably have some level of exposure.

The larger microplastics are more likely to harm, if any, through chemical toxicity.

Another hypothesis is that environmental microplastics may draw chemical pollutants, which they then transmit to animals through their diet.

Animals ingest pollutants from water and food anyway, so it's possible that, if mostly uncontaminated when swallowed, plastic specks could assist in removing pollutants from animal guts.

When it comes to marine organisms, at least, the most basic mode of harm may be that the organisms swallow plastic particles that have no nutritional value and don't consume sufficient food to survive.