Microplastics, Microbeads & Regulations: 2016 State of the Union
Microplastics are defined as plastics smaller than 5 mm in diameter that can be categorized as primary or secondary microplastics, with primary being intentionally produced, and secondary being the decomposition or mechanical breakdown of larger macroplastics. Microbeads are tiny pieces of plastic added to personal care products, such as face and body washes and toothpastes, to act as an abrasive. Knowledge of the amount of microbeads used in consumer products is limited, and the extent of microbeads going down the drain from rinse off products into the sewage system is largely unknown.
On Monday December 28, 2015 president Obama signed the “Microbead-Free Waters Act of 2015” which prohibits the manufacture and introduction into interstate commerce of rinse-off cosmetics containing intentionally-added plastic microbeads starting July 2017. Prior to this, ten states had banned, and four other states were considering a ban, of microbeads in personal care products. Even before federal and state regulations, many companies voluntarily removed microbeads from their products.
Monitoring data on microplastics does not suggest microbeads are the major source of microplastics in surface water and sediments. So where are all the microbeads going? Preliminary studies show approximately 99.9% are removed at wastewater treatment plants and end up in sludge. The fate of remaining microbeads that leave as effluent is unknown. Given their small size and weight, they are not expected to settle out of the water column into sediment unless they aggregate or pick up weight from biofouling. Perhaps they are mechanically broken down into nanoplastics and avoid detection by monitoring sieves.
Ultimately it’s a complex question because there is no definitive detection technique currently available that allows for unequivocal identification of primary versus secondary microplastics and therefore, uncertainty in the occurrence data abounds with most published studies to date.
In July 2015, National Oceanic and Atmospheric Administration (NOAA) produced a laboratory method that standardizes detection using a series of sieves, organic debris digestion and microscopic examination. This technique is labor intensive and still cannot discern between primary and secondary microplastics. Further efforts are underway to characterize microplastic particle size and shape in addition to polymer composition using Fourier-transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR). NOAA, along with partners, are working to refine the quantification method to provide more information about particle size, shape, and polymer type.
Regardless of detection issues, microplastics and even nanoplastics have been found in aquatic animals, surface waters, marine waters, and table salt. The elephant in the room is: do these microplastics pose a risk to public or environmental health? This was the topic of an US Environmental Protection Agency (US EPA) and National Research Committee forum in February 2015. Preliminary studies thus far demonstrate microplastics or nanoplastics can cause harm to aquatic benthic organisms, potentially sorb or desorb toxic chemicals or microorganisms and potentially bioaccumulate.
Waterborne has been closely tracking microplastic regulation and is uniquely qualified in tackling the complex issues of exposure and potential toxicological hazards of microplastics and nanoplastics with a team of hydrogeologists, exposure scientists, water and sediment monitoring specialists, ecotoxicologists, toxicologists and risk assessors. With questions regarding microplastics, contact Nikki Maples-Reynolds, Toxicologist, at firstname.lastname@example.org.