Study looks into effects of nanoparticles from personal care products on crops

The study aims to specifically research two manufactured nanomaterials (MNMs), which are said to be included in personal care products such as sunscreens, lotions and color cosmetics.

A team from the University of California’s Santa Barbara’s Bren School for Environmental Science & Management, in collaboration with scientists at the university’s Center for Environmental Implications of Nanotechnology, University of Texas at El Paso and Columbia University were involved in the study, which was published in the most recent edition of the Journal Proceedings of the National Academy of Scientists.

“Our society has become more environmentally aware in the last few decades, and that results in our government and scientists asking questions about the safety of new types of chemical ingredients, “​ said senior study author Patricia Holden, a professor at Bren School.

Implications of nanomaterials when they are washed down the drain​

The research has been funded by the National Science Foundation (NSF) and the US Environmental Protection Agency (EPA), and aims to discover environmental implications from a range of consumer goods that contain tiny metal nanoparticles that are washed down the drain, after which they can enter the environment.

Holden says that ultimately, the goal of the research is to find more environmentally compatible substitutes to the potentially hazardous nanoparticles.

Soybean was chosen because it is an important crop worldwide and previous studies have shown that it is vulnerable to the MNM nanomaterials. Studies have found that crop yield and quality can be affected when MNMs are present in the soil.

Nano-based zinc oxide from sunscreens​

Specific to cosmetic and personal care products, the scientists studied the effects of nano-based zinc oxide, which is commonly used in sunscreens, lotions and make-up, which can end up in the soil after it is washed off, then going on through sewerage systems to water treatment facilities, where the resulting slurry is often used as fertilizer by farmers.

Breaking this process down, the zinc oxide particles may dissolve or else they remain in the processed wastewater after treatment. The resulting biosolids at the end of the treatment is used as fertilizers for a wide variety of soils throughout the US.

Although the EPA requires pretreatment programs to limit metal discharge, there are no specific regulations for monitoring MNMs, despite the fact that they are detectable in the biosolids.

The study results showed that soybean plants grown in soil that contained bioaccumulated zinc is absorbed into the stems, leaves and beans, in turn effecting the food quality.

Eating soybeans containing the zinc may not be harmful​

However, the author did also report that it may not be harmful to humans if they were to consume soybean products that contained the zinc in the for form of ions or salts contained in the plants.

“There could be hotspots, places where you have accumulation, including near manufacturing sites where the materials are being made, or if there are spills,”​ said Holden.

“We have very limited information the quantity or state of these synthetic nanomaterials in the environment right now. We know they’re being used in consumer goods, and we know they’re going down the drain.”​