Imagine dividing a single grain of sand into a million pieces. This is the scale of nanoparticles: tiny man-made bits of matter that are being used in a widening array of consumer products, from the microprocessor in your computer to odor-resistant workout clothes. Lok Pokhrel, Assistant Professor of Environmental Health, says that while nanoparticles are proving their usefulness, they are entering the environment at an alarming rate—and the consequences to our ecosystem and human health are still unknown.
Pokhrel studies the effects of nanoparticles on wide array of organisms including plants, microbes, invertebrates, and human cells. He says that over the last 20 years nanomaterials have become entwined in our lives, both in the products we use and in the environment, as those products are used and discarded. Pokhrel says that some nanoparticles can be toxic to microbes, but there are unanswered questions about their effects on larger organisms. “We still don’t have a clear understanding of nanoparticles’ short-term or long-term risks, especially for humans,” he says.
Pokhrel argues that nanotechnology is evolving so quickly that environmental health and safety researchers and government regulatory agencies have difficulty keeping up. That’s partly because of the unique attributes of nanoparticles themselves. When a particle is built from just a few atoms or molecules, making it even slightly larger or smaller can cause it to behave very differently. “If you change the size a little bit, its properties change—and its toxicity changes,” says Pokhrel.
And that has big implications. When a company creates a nanoparticle and begins using it in consumer products, other researchers might not be able to independently replicate that particle in order to test its toxicity. “What I study may not be the same thing as what the company uses in its products,” says Pokhrel, “because the company doesn’t provide detailed information about those nanomaterials.”
But nanotechnology has a bright side, too. Pokhrel points to gold particles used to detect cancer, silica particles that harvest solar energy, and silver nanoparticles that can purify water. And Pokhrel is now researching how nanoparticles could be used to fight mosquitoes that carry the Zika virus. But big questions remain: How do nanomaterials accumulate in water sources? How do they interact with soil and other chemicals? How are they absorbed by plants—and ultimately by the human body?
Pokhrel and other researchers are working hard to answer those questions. Ultimately, he says, increasing collaboration—between consumer product industries, academic researchers and regulatory agencies—will maximize the benefits and minimize the potential harms of nanotechnology. “In order to understand the potential risks,” he says, “there has to be better coordination.”
Read about more of Lok Pokhrel's research here.