You can't see nanoplastics with the naked eye, but they're everywhere - including your body.
Tinier than the better-known microplastics, these plastic particles range from one nanometer to one micrometer in size; a human hair, by comparison, is about 100 micrometers thick.
"Nanoplastics are present in drinking water, food and the air, and have been detected in both tap water and bottled water," explained Binghamton University Assistant Professor of Chemistry Huiyuan Guo. "They are widely detected in the environment."
Guo and Associate Professor of Biological Sciences Anthony Fiumera recently received a $500,000 grant from the National Science Foundation to investigate how nanoplastics pass from mothers to their offspring. The interdisciplinary project will create special trackable versions of these particles to see exactly how they move through organisms and understand why they cause harm that can last for generations.
The researchers will use Daphnia magna, a tiny species of freshwater crustacean commonly called water fleas, as the animal model. Daphnia, which have transparent bodies, reproduce quickly and are sensitive to environmental stress; they are often used as an indicator species in environmental toxicity testing, Fiumera explained.
"They're actually a great model to study transgenerational or epigenetic inheritance," he added. "They're also surprisingly similar to humans in the way in which that works."
Research has already demonstrated that nanoplastics can affect aquatic species such as daphnia, affecting their survival and reproductive capacities; other research has investigated potential toxicity on a molecular level. However, this research typically focuses on a single generation or short-term effects of toxicity, Guo said.
Water fleas are close to the bottom of the food chain, feeding on small particles such as algae. In turn, daphnia are food for fish and other animals; what affects them can thus end up affecting other species in an ecosystem's food chain.
Detecting nanoplastics
A mother daphnia may directly transmit the tiny plastic particles to her offspring. In fact, Guo's lab has already published research on how nanoplastics can transfer from a daphnia's intestines to other body parts; from there, they will explore how these tiny particles may breach the biological barrier between mother and offspring.
First, however, researchers need to detect the tiny particles, a difficult feat.
"That's why our first objective is to develop a detectable nanoplastic model," Guo said. "We can use it to better understand how they transfer from one generation to another."
They will use two approaches to detect the nanoplastics in daphnia: confocal surface-enhanced Raman spectroscopy (SERS) and inductively coupled plasma mass spectrometry (ICP-MS).
They will also consider how nanoparticles affect gene expression in the mother, her offspring and subsequent generations.
"It's possible that these particles are being physically transferred, but it's also possible that changes in gene expression are being inherited in addition to the actual nanoparticles," Fiumera said. "That's one of the things we're trying to figure out: How important is the actual particle transfer versus the transfer of these epigenetic effects?"
While the grant lasts for three years, Guo and Fiumera plan to continue their work long into the future, looking at different animal models and addressing additional questions.
Here's one. Plastics have traditionally been petroleum-based; however, recent years have seen the development and adoption of bioplastics, made from renewable biomass sources, as an eco-friendly alternative. How might the shift to bioplastics affect the environment over the long term?
"Some of these plastics are considered biodegradable. However, this biodegradability also means they are more likely to become smaller particles like nanoplastics," Guo said. "How do you know which one is safer?"
To answer that question, the researchers will compare the different types of nanoplastics to see which are more toxic and which are more easily transmitted to future generations.
Future generations are also a focus in a different way: A community outreach component seeks to foster the next generation of scientists, in collaboration with the New York State Master Teacher Program and the Go Green Institute, which provides an intensive, 10-day hands-on learning experience for middle- and high-school students.
Some high school and first-year University lab classes already study daphnia, Guo said. The researchers propose to integrate their project into an undergraduate research course at the University and pilot-test related scientific kits through the Go Green Institute summer camp. These kits can then be distributed to K-12 schools and the local community to conduct their own research into the environmental impact of plastic.
"It's a pipeline to give an authentic research experience to as many students as we can," Fiumera said.
