Remote sensing research helps monitor plastic pollution in rivers
A first-of-its-kind study shows how remote sensing can help monitor and remove plastic debris from freshwater environments like the Mississippi River. The findings from Ph.D. student Mohammadali Olyaei, his advisor Ardeshir Ebtehaj, and senior research associate Christopher R. Ellis, were published in the journal ScientificData.
Plastic pollution in oceans is one of the leading challenges regarding pollution. Often overlooked is the fact that a lot of plastic debris makes its way to our oceans through rivers. Previous studies on removing plastic debris were based on gathering water samples, a practice that is labor-intensive, time-consuming, and expensive.
This study used remote sensing technology to provide more cost-effective solutions. Olyaei, Ebtehaj, and Ellis conducted their research in the Mississippi River, the piece of it that through the University of Minnesota’s St. Anthony Falls Laboratory. Thus, they were able to test their theory in the actual conditions of the Mississippi River.
The researchers monitored and classified various types of plastic debris using a spectroradiometer and a digital single-lens reflex camera.
Olyaei, M., Ebtehaj, A. & Ellis, C.R. A Hyperspectral Reflectance Database of Plastic Debris with Different Fractional Abundance in River Systems. Sci Data 11, 1253 (2024). Full text
Figure 1 in the Scientific Data article shows the research set up.
The technology uses spectral reflectance properties, or wavelengths in the electromagnetic spectrum, to pinpoint specific types of plastic. Knowing the specific wavelengths of plastic materials enables the sensing technology to differentiate plastics from materials found naturally in freshwater environments, such as seaweed, sediments, driftwood, and water foams. Mohammadali Olyaei explained, “We could use this technology to identify different types of plastics in the water simultaneously. This is key information we need when employing other technology, like drones, to capture and remove plastic debris in natural environments.”
The researchers hope to continue their research on a larger scale, studying where plastic debris comes from, how it moves across river systems, and how they can remove it. “As these plastics spread more and more, their control becomes more and more challenging,” said Ardeshir Ebtehaj. The researchers envision using this technology to catch plastic debris upstream to keep plastics from ever reaching the ocean.