Julie is a geologist by training and education, but now is more a practicing Jack-of-all-trades, as many of us are. She splits her time between field work, lab work, and administration, and between harmful algal blooms and microplastics. Some of Julie’s most recent work involves trying to investigate and develop better methods of standardization for microplastics analysis. That really made me excited to talk with her. Julie remarked that standardization is a huge problem, and once chemists entered the field, everything became much more analytical. In some ways, this is good, we are more accurate in our estimates, but it means that the research is becoming increasingly time-consuming and equipment intensive. This is especially challenging for those of us working at smaller, less research-focused facilities. Julie uses a bench top FTIR to verify the microplastics in her samples; it took students 90 hours to verify the microplastics in two samples, one fiber at a time. Julie and I share the same limitation by working primarily with undergraduate students, whose time and experience is limited. It really resonated with me when Julie commented, “Our greatest contribution may be to train the students that will go on to do the really important work that we find difficult to do in our labs.”
Preliminary work on methods development included surface water, bed sediment, and beach sand. Early on she has was involved in an interlaboratory comparison study in which various labs were given water samples spiked with the same amount of microplastics. It turns out the results were closer than most people expected! One issue with sediments in particular is that they vary in consistency. Puget Sound mud is sticky. Chesapeake Bay mud is sandy. Beach sands in Puget Sound vary from place to place, whereas tropical island sands are winnowed and quite uniform. If all US-based researchers are going to agree on a method, it will have to accommodate these differences.
Another big problem that Julie highlighted, and that I agree with, is the different mesh sizes that people use for water sampling or sediment sieving. When scientists realized that the megaplastic debris was breaking down, they started to look at microdebris. This term was new to me, and I love it because it recognizes that often times, we are not sure whether these small particles are plastic, but we know they are debris. A study in the Great Lakes used similar methods to Julie’s, but the number of plastic particles was much lower. Does this mean the Great Lakes are cleaner than Puget Sound? No, not necessarily, because the size of the mesh in the net was much larger, so the smaller microdebris particles slipped right through.
Julie has also been looking at the temporal and spatial distribution of microplastics in sediments at ten stations in Puget Sound and off the West Coast of Vancouver Island since 2014; which I think makes it one of the longest temporal sampling studies we have in the US. The number of fibers has not changed over this time frame; but I would bet that it will increase over the next 10 or 20 years. Also, perhaps surprisingly, the two sites are not very different. Perhaps the buoyancy of the particles, combined with the current, keep the microplastics from being deposited in Puget Sound. Perhaps the active fishing industry off the coast of Vancouver Island contributes a fair number of particles.
I asked Julie what she thought were the challenges for us microplastic researchers. She answered, “I am going to be frank with you. As a scientist, I struggle with the so-what. What drives policy is human health. I am struggling with being convinced of the danger to human health from microplastics.” I agree, and I think many others do as well. We now have many excellent scientists working on this issue, and hopefully their work will provide guidance to how concerned we really should be about human health, and this in turn might lead to the development of some policies that will help protect not only humans, but also the complete spectrum of other species that inhabit this earth, and likewise breathe in and eat microplastics.