engineering careers  University of Warwick creates Fluorescent dye to highlight 99% of hidden ocean micro-plastics
engineering careers  University of Warwick creates Fluorescent dye to highlight 99% of hidden ocean micro-plastics

With the smallest microplastics in oceans going largely undetected the University of Warwick has developed an innovative and cheap new method of detecting microplastics as small as the width of a human hair.

Up to now, fieldwork surveys have reported that only 1% of the plastic waste in the oceans has been found. The team behind the new technology hope this research could lead to discovering the missing 99%.

Micro-plastics are ‘created’ as the corrosive forces of the ocean breaks up the mMillions of metric tons of plastic washed into the sea each year. Everything from bottles, cigarette lighters and to pieces of packaging end up broken into tiny fragments that are difficult to track.

The problem is that while these tiny plastic fragments can measure as little as the width of a human hair there are estimates of between 93k and 236k metric tons of this waste floating on the surface of the ocean. This is a huge problem for the ocean eco-system as it is consumed by a range of filter-feeding animals and eventually works it ways back into the human food-chain.

We don’t know how much of it is on the seafloor, we don’t know how much of it is on the coastlines or beaches, trapped in mangrove forests, those kinds of things, and we don’t know how much is in the guts of marine animals and organisms … As long as we don’t know that, we don’t know where marine life interacts with those plastics and we also don’t know where is best to take out the plastic or to clean it up. Erik van Sebille, the lead author on that study


The idea is that before we can think about to clean up the oceans we should better understand the problem and the next phase of Sebille research will be funded by the European Union and look at creating 3D distribution maps of ocean plastics.

The team at Warwick’s School of Life Sciences were able to use a type of fluorescent dye (Nile Red) to bind to plastic floating in water and these particles then became illuminated when viewed through a fluorescence microscope.

This should enable scientists in the field to to tell micro-plastics apart from natural materials and count them with much more ease in future.

In field tests around Plymouth the team were able to show they could detect microplastics within the samples at sizes as small as 20 micrometers. The tests – alarmingly – showed a far larger amount of micro-plastics in the water than would have been traditionally detected and that the most common material was polypropylene (used in food packaging).

Now the technique has been proven to work the goal will be to scale up the technique to work on a larger scale.

Published as “Lost, but Found with Nile Red: A Novel Method for Detecting and Quantifying Small Microplastics (1 mm to 20 μm) in Environmental Samples” in the journal Environmental Science & Technology.

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