We study marine microplastics through both on-the-water and shore-based water sampling. Once we collect our samples, the next step is to process them to separate the microplastics they contain. We then analyze these microplastics and record our findings, which we publish through various means.
Studying marine microplastics is important for lots of reasons. Microplastics are abundant in our waters, and they directly impact the health of our environment—which in turn impacts our health as humans. The chemicals in plastics have been shown to cause developmental delays, cancers, and other serious health conditions, and these chemicals are virtually inescapable due to the prevalence of microplastics in the water, the air, and the food chain.
So, how do we do it?
Studying marine microplastics is a multi-step process. This process starts with sampling. Currently, we gather water samples through three primary means. After we collect samples, we process and analyze them, and then we report our findings to the scientific community and the public at large.
How Do We Collect Samples of Marine Microplastics?
We study marine microplastics using both on-the-water and shore-based water sampling. Here is an overview of the three methods we use:
1. Pulling Microplastics Trawls with Kayaks in Inshore Waterways
Kayaks are our primary mode of travel when collecting samples in inshore waterways. To collect samples, we pull a microplastics trawl through the water. We currently have two trawls—one based on a previously published design and another that is our own design. While the previously published design is made of wood and requires a plastic-based sealant (which needs to be reapplied over time), our design is plastic-free and virtually maintenance-free as it is made of aluminum and stainless steel.
In tidal waters, we typically try to go sampling around slack tide. When the tide is not completely slack, we paddle against the current. Rather than measuring the distance we cover, we use a flow meter to track the volume of water that passes through the trawl on each sample run. This allows us to accurately calculate the concentration of microplastics in the water.
Each trawl is equipped with a detachable collection bag; and, after each sample run, we place the collection bag into a glass jar, which we then seal. If we are conducting multiple sample runs on a single outing (which is typically the case), we will bring multiple nets and collection bags so that one sample run does not contaminate the next.
2. Pulling Microplastics Trawls with Boats in Coastal Waters
When conducting microplastics sampling in coastal waters, we use a boat to pull our trawls. We go slow when sampling—typically around one knot—keeping just enough speed to maintain steerage. This reduces the strain on our trawls; and, since we calculate the concentration of microplastics in the water based on water flow rate rather than speed over ground, our speed is immaterial to our research.
Our process for collecting samples via boat is the same as it is for collecting samples via kayak. Here too, we bring multiple nets, collection bags, and glass jars on each trip so that we can collect and maintain the integrity of multiple samples.
3. Conducting Shore-Based “Bucket Sampling”
The third method we use is shore-based “bucket sampling.” Notably, despite its name, bucket sampling does not actually involve the use of a bucket. Instead, when we “bucket sample,” we use a glass container to collect water samples that we pour through a series of sieves. These sieves have progressively finer stainless steel mesh, and the final sieve in the series is what collects the microplastics—while the water flows all the way through.
In order to collect multiple samples without cross-contamination, we bring a container of ultra-filtered water with us. We use this ultra-filtered water—which is plastic-free—to thoroughly rinse our sieves between each sample run. For the sieve that contains the microplastics that we have collected, we use our ultra-filtered water to rinse the microplastics into a glass jar for future processing.
All three of these methods are equally effective for studying marine microplastics. By employing multiple sampling methods, we are able to expand the scope of our research, providing us greater insight into the true scope of the global microplastics problem.
How Do We Identify Microplastics in the Water?
Of course, collecting samples is just the first step in the process. Once we collect samples, we then need to analyze them.
But, before we can analyze them, we need to process them. If we looked at our samples under a microscope without processing them, it would not be possible to accurately assess the concentration of microplastics due to the significant presence of biologic and mineral material. Processing (which itself is a multi-step process) leaves us with clean samples that we can analyze and report on with confidence.
We use several chemicals and processes to clean our samples. We also use several methods to analyze our samples after they have been cleaned. These include examining our samples using stereo and compound microscopes, examining them with 395nm wavelength UV light, and “hot needle” testing, among others.
For an overview of how we process microplastics samples for analysis, you can read the first report we published discussing samples we collected on Edisto Island, South Carolina.
What Can You Do if You Are Interested in Helping?
If you are interested in contributing to our efforts to study marine microplastics, what can you do? If you are in the Charleston, South Carolina area and are interested in seeing what we do first-hand, we invite you to get in touch. If you are interested in working with us to collect and analyze samples elsewhere, we invite you to get in touch in this scenario as well. We are interested in working with like-minded organizations, and we can bring our resources and expertise to collect and analyze samples anywhere in the world.
Donating is another way to support our efforts, and we also offer sponsorship opportunities. We appreciate your interest in our work, and we encourage you to get in touch if you have questions.