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Over 300 million tons of plastics are produced each year, out of which only up to 40 percent are recycled or incinerated. The majority end up in landfills or are improperly discarded in the environment, leading over time to their fragmentation into smaller plastic items.

CREDIT: Khalifa University
Ludovic Dumée

Ludovic (Ludo) Dumée is an assistant professor within the Chemical Engineering Department at Khalifa University who leads the Advanced Separation Materials team. Read more›››

His research interests span from functional and reactive materials engineering to their application across environmental applications. In 2020, he received the Membrane Society of Australasia Science award for his work on microplastics separation. He can be reached at‹‹‹ Read less

Such “microplastics,” whose maximum dimension falls below 5 millimeters, are ultimately released into waterways and represent a major threat to global ecosystems, the entire food chain as well as many human industrial activities that rely on river or sea-water intake.

The fragmentation of such microplastics may also lead to the formation of nanoplastics, with dimensions below the micrometer level. These are much more difficult to quantify and identify, and they represent key challenges for engineers and researchers.

Why may microplastics enter the food chain and affect humans? Microplastics are reported in the guts of multiple avian or sea-life species that often mistake microplastics for food. Ingested microplastics may accumulate in their digestive system. Besides representing a major source of pain, it can lead to the animals’ premature death. Scavengers then feed on their carcasses, leading to further ingestion of microplastics up the food chain.

Over time microplastics contamination carries over to greater predators and human beings. It is estimated that humans ingest between 50,000 and 100,000 microplastics every year, arising from overusage of plastic bottles for soft drinks or packaged-water consumption, but also through uncontrolled fragmentation and release from packaging materials.

Examples of risks associated to plastic ingestion for human and their uptake by our body through diffusion in the blood system are multiple and daunting, not only due to the increased risk of cancer for exposed organs, but also because microplastics may carry over pathogenic contaminants, such as heavy metals or persistent organic pollutants. Such surface-contaminated microplastics, given the high buoyancy of plastic materials and their ability to float, may therefore act as cargos to further disseminate other contaminants over much larger distances than the single contaminants could achieve.

How can microplastics impact human industrial activities? Besides the food industry, a key area affected by the presence of micro or nanoplastics is the water industry.

Microplastics that enter the waterways may carry over pathogenic contaminants, such as heavy metals or persistent organic pollutants. CREDIT: Unsplash

The intake waters, feeding wastewater-treatment and desalination plants, may contain, depending on their location and origin, various levels of nano or microplastics, which may damage existing treatment processes.

For instance, the presence of microplastics in microbial-digestion bioreactors would disturb the microbial ecosystem and floc formation, that is the size of the colonies and their stability, thus reducing the efficiency of the process.

Deposits of nano or microplastics may directly damage membrane-separation steps, potentially leading to mechanical abrasion, as well as to accumulation onto the membranes, reducing the separation and flux performance. These phenomena were found to increase substantially the cost of water desalination and processing, sometimes detrimentally affecting the quality of produced water.

In addition, studies showed also that, depending on the treatment trains in place, microplastics may be further concentrated across the treatment units, leading to discharge of sludge or downstream waters richer in microplastics at the end of the water-treatment process.

How can you help? Discard your plastic wastes properly and ensure that you put them in the right bin without leaving a chance for discarded items to get into our beautiful waterways. Also privilege sustainable-packaging options and limit your usage of single-use items.

What is needed at this point to better understand risks? Researchers are developing advanced tools and platforms to detect nano and microplastics in wastewaters, to better understand their interactions with microbial organisms, water-treatment operations and assess their health and economic impact. We develop strategies to reveal the true extent of pollution within local ecosystems and understand the impact of plastic fragments of various sizes or shapes on the performance of separation systems. We also study the impact of microplastics on human health and their potential diffusion into our bodies to better prevent long-term diseases.

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