This is the 29th entry in the Armed with Science series, Dispatches from Antarctica. The series features Air Force Lt. Col. Ed Vaughan’s first-hand experiences on OPERATION: DEEP FREEZE, the Defense Department’s support of National Science Foundation research in Antarctica.
1 November 2010, McMurdo Station, Antarctica: Microplastics…Ocean Pollution writ Large
My sister told me to always clip the circles on the plastic six-pack holders. The theory is that such measures may prevent sea creatures from getting caught up in them. I don’t know if that works or not, but it made me think about all the plastics that find their way to the ocean. Turns out that even the so-called biodegradable plastics (made from plant materials) only biodegrade when composted in soil. In the ocean, it seems they float around like all the other trash.
Also, I’ve seen photos and read news stories about gulls, sea turtles, and marine mammals found dead due to entanglement with plastic garbage. Living in the Hawaiian Islands, we hear news about a “discovery” of the Great Pacific Garbage Patch, a swirling, floating ad hoc plastics dump, is claimed to be larger than the state of Texas? Even if such a thing couldn’t be quantified in that way, as explained by NOAA in their Marine Debris web portal, its mere existence would be significant.
As NOAA states very clearly, “…regardless of the exact size, mass, and location of the “garbage patch,” manmade debris does not belong in our oceans and waterways.”
But what happens over the long haul? Do these plastics mechanically degrade in the ocean and become harmless? According to Dr. Mary Sewell, senior lecturer (professor) at University of Auckland in New Zealand, petroleum-based plastics do break down into smaller bits over a long period of time. And these smaller bits present a whole new range of hazards to marine life, both big and very, very small.
As Dr. Sewell explains in the above video, microplastic particles are generally described as pieces less than 5mm in size, but can be as small as a few microns. However, they don’t only come from large plastics which are broken down over time. They also come directly manufactured at the micro-scale for use in consumer cosmetics and other products.
Although Dr. Sewell’s work in Antarctica, as part of Dr. Gretchen Hofmann’s NSF-funded team, is concerned with rising acidification in oceans, Dr. Sewell’s collaboration with Dr. Lisa Fendall is the topic of this Dispatch. The abstract of their recently published paper is here:
Contributing to marine pollution by washing your face: Microplastics in facial cleansers
Authors: Lisa S Fendall, Mary A Sewell
Journal: Marine pollution bulletin
Plastics pollution in the ocean is an area of growing concern, with research efforts focusing on both the macroplastic (>5mm) and microplastic (<5mm) fractions. In the 1990s it was recognized that a minor source of microplastic pollution was derived from liquid hand-cleansers that would have been rarely used by the average consumer. In 2009, however, the average consumer is likely to be using microplastic-containing products on a daily basis, as the majority of facial cleansers now contain polyethylene microplastics which are not captured by wastewater plants and will enter the oceans. Four microplastic-containing facial cleansers available in New Zealand supermarkets were used to quantify the size of the polythelene fragments. Three-quarters of the brands had a modal size of <100 microns and could be immediately ingested by planktonic organisms at the base of the food chain. Over time the microplastics will be subject to UV-degradation and absorb hydrophobic materials such as PCBs, making them smaller and more toxic in the long-term. Marine scientists need to educate the public to the dangers of using products that pose an immediate and long-term threat to the health of the oceans and the food we eat.
Marine pollution bulletin. 01/05/2009
Dr. Sewell also adds that as nanotechnology becomes more prevalent in the manufacture of commercial cosmetics and cleansers, the second and third order environmental impacts of the material used at that scale, are unclear. Dr. Sewell suggests that further investigation into the impact of micro- and nano-scale plastics on microscopic marine life, such as plankton, is warranted.