Microplastics in the Aquatic Environment

What are Microplastics?

A microplastics sample after in-lab processing. Particles that have a fluorescence are assumed plastic.

Microplastics are small particles that come from larger plastics. We call larger plastics macroplastics. Over time as macroplastics break down they become microplastics. Microplastics research is relatively new, so researchers like us are trying to find the impact that they have on the environment. How do they affect the ecosystem? Or human health?  Before we can understand how they affect the environment , we need to know how many microplastics there are in the environment.  Based on the research of other scientists we know, microplastics put aquatic ecosystems at risk because they can block the gastrointestinal tracts of plankton and other small animals, and can deliver endocrine-disrupting compounds to all parts of the aquatic food chain.

What Has Our Lab Done?

We started looking for microplastics in the southern end of Cayuga Lake in 2017 in collaboration with the Ithaca Area Wastewater Treatment Facility. We do this using a “manta net”, so named because of the large mouth-like opening and extending tail.  Our net is 3 meters long, and has netting with 50 um holes, allowing us to capture small microplastics.  We tow the net in a big circle at each of 3 locations in the lake, and in a straight line in the Inlet.  We then rinse all the microplastics from the net into a glass jar to take back to the lab at Ithaca College.

Manta Net Used For Sampling

Here's How We Do It

1. Density Separate

We first separate the plastics from the silt and sand using their different densities. By supersaturating the sample, we can drive the plastics to the top and the silt and sand to the bottom of a separatory funnel. ​

2. Digest

We then take the plastics portion and subject it to concentrated hydrogen peroxide to breakdown any organic material that might have floated with the plastics.​

3. Dye & Vacuum

The next step is to color the particles with Nile Red dye and vacuum filter the sample onto a special piece of filter paper.​

4. Photograph

Then we photograph and count the dyed particles under a dissection microscope using a grid system that allows us to estimate how many plastics would be on the whole filter paper.

It Wouldn't be Science Without Some Math!

Our Current Estimate:

Microplastic Particles In Cayuga Lake!

Since we know how much water we passed through the net and how much surface area we sampled, we can calculate how many microplastics are in that volume of water.  And since we know the surface area and volume of the lake, we can calculate how many microplastics we estimate are in the whole lake by volume and by surface area. 

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