Here's a few things to consider the next time you think about throwing a plastic item in the trash, the ocean or anywhere other than a recycling bin.
A recent survey suggests that every hour people around the world discard 5.7 million toothpaste tubes, 570,000 cell phones and 2.3 million pairs of sneakers. By 2050, researchers believe the plastic and microplastic particles in the oceans could outweigh the fish.
Although microplastics were first discovered more than 60 years ago, it wasn't until the early 2000s that they emerged as a field of study. Twenty years later, you would be hard-pressed not to read a headline about these pencil-eraser-sized bits of plastic debris and the research being conducted.
A leader in this research field, Duke University serves as a vast repository of research and information about microplastics, with more than 60 faculty, students, staff and postdocs across 12 schools and departments as part of its Plastic Pollution Working Group . It serves as the central hub to share their work related to plastic pollution.
What Are Microplastics?
To understand why microplastics - and their even smaller cousin nanoplastics - are bad for the environment, people and animals, it's important to know what they are, where they originate and how are they ingested.
Microplastics generally form when plastics break into tiny particles, some so small they cannot be seen. But it's not just these particles that pose a hazard, it's also the chemicals they contain. They can become contaminated during production or after the plastic begins to break down. Chemicals such as BPA, phthalates, and PFAS can leach out and be absorbed into the body.
Jason Somarelli, assistant professor of medical oncology in the Duke Department of Medicine, is working with two teams to determine which mixtures of plastic additives are the most harmful, rather than looking at the impact of the chemicals separately.
"It gets into your body as a mixture. It's the plastic, plus the chemicals, plus environmental toxins, which is more like a chemical soup and that's what we want to test. We want to discover which additive combinations have the most negative impacts on your health," Somarelli said.
Where Are Microplastics Found?
Microplastics can be found in the food we eat, the water we drink, the clothing we wear, the oceans in which we swim and even the air we breathe.
"Plastic is not a natural substance in the human body, yet it has penetrated every single aspect of our lives from conception to death and it's going to have a cumulative effect over time," said Michelle Nowlin , clinical professor and co-director of Duke Law's Environmental Law and Policy Clinic .
Nowlin is a long-time champion of the environment. She and others at the clinic have focused on plastic pollution, identifying interventions and policy solutions for different points in the plastics lifecycle - from production to use to disposal - to eliminate, reduce, or mitigate the harms of plastics.
Plastics consist of long chains of carbon and thousands of chemical compounds that modify their function, known as additives. If ingested, these chemicals can cause serious health issues.
James B. Duke Distinguished Professor of Civil and Environmental Engineering Mark Wiesner explains that while most of us have plastics in our bloodstream and even in our brains, the consequences of that exposure are actively being explored.
What Are the Impacts of Microplastics?
Microplastics can have serious consequences. They have been linked to cancer, Parkinson's disease and dementia .
"Our study suggests that the emergence of micro and nanoplastics in the environment might represent a new toxin challenge with respect to Parkinson's disease risk and progression," said Andrew West, Duke professor in the Department of Pharmacology and Cancer Biology . "This is especially concerning given the predicted increase in concentrations of these contaminants in our water and food supplies."
Another study that West was involved in found microplastic concentrations were also higher in the brains of deceased patients who had been diagnosed with dementia compared to the brains of deceased individuals without dementia.
"These results highlight a critical need to better understand the routes of exposure, uptake and clearance pathways and potential health consequences of plastics in human tissues, particularly in the brain," according to the study published in Nature .
It is not just people who are being harmed. Duke researchers found microplastics have infiltrated the tissues of whales and dolphins. The presence of these polymer particles and fibers in these animals suggests that microplastics can travel out of the digestive tract and lodge in the tissues.
Another Duke study found exposure to microplastic fibers causes cellular changes in fish and may disrupt endocrine systems. These fibers which are made of polyester, polypropylene and other types of plastics, are shed or washed off synthetic textiles used in clothing and other consumer and industrial products. Once shed, they enter wastewater and accumulate in oceans, rivers and lakes worldwide, accounting for more than 90 percent of microplastic pollution in some areas. A single garment can shed nearly 2,000 microfibers per wash.
"Until now, most studies have focused primarily on looking for the presence of plastics in animals, without identifying what the effects on various tissues might be. But that's exactly where our study suggests the science needs to go," said Melissa Chernick , one of the study's authors and a research technician with the Nicholas School of the Environment.
What Can Be Done?
Research is essential for understanding this widespread issue, through academic units of Duke and as part of the focus areas of oceans and health in the Duke Climate Commitment.
Duke researchers have been looking at several possibilities. One is breaking down plastics using bacteria . A Bass Connections team is investigating a bacteria called Thermus thermophilus that can degrade plastics at higher temperatures. Another is called Pseudomonas stutzeri bacteria, a strain that has been shown to have degrading properties on more complex plastic polymers such as polyethylene terephthalate or "PET" plastic, commonly used thermoplastic polymer resin, primarily used in food and beverage packaging.
Looking ahead, the group hopes to engineer a bioreactor that can break plastic down into chemical components that can be reused.
By gaining a better understanding of the effects microplastics have on our environment and on living organisms, researchers aim to develop sustainable and effective solutions both today and in the future.
