Microplastics are ubiquitous in terrestrial and aquatic environments and have been found even in remote regions of the world. To date very little is known about atmospheric transport of microplastics through precipitation and whether this occurs in Alaska. Some Alaskans rely on precipitation as a source of drinking water, therefore determining the presence and location of microplastics in precipitation is of importance to state water resource management.
Two objectives exist for this project: 1) to discover if microplastics exist in precipitation in Alaska, and if they do, if microplastics persist in remote areas as well as urban locations; and 2) create a map that can be shared with stakeholders showing the presence or absence of microplastics from precipitation across the state.
In the time frame of this project, the WERC team purchased a trinocular fluorescence microscope (T670Q-PL-FL, Amscope) and developed a method for identifying and quantifying different microplastic types, including polypropylene, polyethylene, high density polyethylene (HDPE), polystyrene, and polyvinyl chloride (PVC).
Samples of snow, rain, and stream/lake water were collected over several hundred miles. Sampling was more limited in scope than originally intended due to the pandemic; samples were collected mostly by researchers across the state, but did include some from native community members in villages off the road system.
Our results show that microplastics exist in almost every sample, including those collected from remote snowpack, although microplastic size generally differed between sample types.
