A BIT OF BACKGROUND
The abundance of plastic on coastal beaches is constantly changing. Waves deposit plastics but also wash them away. The dynamic nature of beaches makes it challenging to understand plastic abundance. Like sand, the plastics are constantly reworked by the waves, some may be newly deposited and others may be moved up and down/back and forth along the beach for many years.
Plastics are found primarily sitting on top of sand where sand was recently or currently wet because even the densest plastics are still less dense than sand and so they “float” on top of it. In dry sand, plastics can be mixed into deeper layers of sand.
Plastics are found primarily at the high tide mark on beaches and on the highest line reached by each wave. Also, they are found in restricted areas, like along a jetty or harbor wall.
LEARN THE VOCABULARY
Microplastic – any piece of plastic equal to or less than 5 mm in size
Macroplastic – any piece of plastic debris larger than 5 mm in size
Primary Microplastic – a manufactured microplastic, e.g. a resin pellet or microbead
Secondary Microplastic – a piece of plastic that broke down into a small (< 5mm) piece from a larger object
Resin pellet – a plastic nugget which will be melted down to produce a plastic object
Transect – a straight line or narrow section through an object or natural feature or across the earth’s surface, along which observations are made or measurements taken.
Wrackline – a line of material deposited along the shoreline
GET YOUR MATERIALS
A 10 m rope
Paper/cloth bag for each transect
KNOW WHAT YOU ARE LOOKING FOR
Plastics are man-made materials that easily end up in our environment. They can take many different shapes and sizes.
The easiest plastics to find are big items that haven’t started to break down yet. Some examples of things to look out for are cigarette butts, bottle caps, bags, wrappers, bottles, etc.
Over time plastics break down due to photodegradation. This is a process where UV light from the sun breaks bonds in the plastic molecules causing the plastic to get brittle, faded, and fractured. The result is the formation of microplastics, tiny, fragmented pieces of plastic smaller than 5 mm in size. Some items you may find are actually manufactured at such small sizes. A common example of this is the resin pellet; small round or cylindrical pellets that are shipped around the world to companies who melt them down and form them into products.
COLLECT YOUR SAMPLES
Before heading out to the beach, print this guide to help you remember the protocol: Trash Trackers Field Guide
1. Travel to your study area – a beach, river bank, lakeshore.
Start by inspecting your study area.
Are you investigating the entire beach, or a certain sub-area?
What is the sediment grain size? Fine sand, coarse sand, pebbles?
What direction does the beach face on average (use an online map or a compass)?
Is the beach curved like a bay, or straight?
At what part of the tidal cycle are you sampling in? High or low?
Do you see a deposit of debris (wrackline) on the foreshore?
2. Set up your first transect:
Walk to the waters edge and find the wrackline. There may be a couple because of the fluctuating tides. Find the one that you think is the most recently deposited one.
Set the 10 m rope on top of and as parallel to the wrackline as possible.
Starting at one end, place the meter stick perpendicular to the rope to mark a 1 meter wide swath.
Take a measurement of your location’s GPS coordinates using Google Maps or the Where am I at? app on a phone. Make sure to record your coordinates using decimal degrees to 5-7 decimal places (e.g. lat, long = 33.7470645, -118.1147850). This is important because the online database requires this format to recognize the coordinates.
Label your collection container. Make sure you include any info you might need later: Location on the beach, Date, Names of team members, Coordinates of location (use Google Maps or the like). For example you could write: “Wrackline, August 3, 2017, Anika Ballent & Katie Allen, 33.7470645, -118.1147850”
3. Collect the sample:
Work your way from one end of the transect to the other, picking up any plastics visible on the surface of the sand, even the really small ones!
As you move along from one end to the other, move the meter stick along with you, so that you know you are only collecting the plastics in the 1 meter wide swath.
HINT! Work in pairs. Starting side by side at the end of the rope, walk forward together, each person collecting plastic in the 50 cm on their side of the rope.
As you collect them, place the plastics in a collection container.
Once you’ve made it to the other end of the rope, you’ve completed your first sample!
If you want to collect additional samples, set up another transect 10 m inland from the first and parallel to the first transect.
Repeat the transect collection, labeling your new sample container with the distance away from the wrackline, e.g. “10 m from Wrackline, August 3, 2017, Anika Ballent & Katie Allen, 33.7470645, -118.1147850”
4. Repeat steps 2 and 3 as many times as you want, but make sure to keep the samples clearly labeled and separated.
ANALYZE YOUR SAMPLES
Analyze your plastic samples in a calm area (best done indoors where it isn’t windy).
Empty the contents of one sample into a tray. A pie tin works great.
Sort the plastics into these categories and record their quantity in a table:
Resin pellets: small round or cylindrical pellets
Solid fragments: pieces of plastic that you can’t identify and that are rigid (not flexible) and solid (not foamy).
Foamy fragments: pieces of plastic that you can’t identify and that are foamy
Flexible film fragments: pieces of plastic that you can’t identify and that are thin and flexible sheets (like a plastic bag)
Whole items: you can tell what the item is and it isn’t broken apart.
Cigarette Filters: count these as their own category
Non-plastic anthropogenic items: man-made materials other than plastic, e.g. paper, glass, metal, rubber, fabric
After sorting, determine the ratio of microplastics to macroplastics by counting the total number of pieces bigger than 5 mm using a ruler or a sieve. Record the number of macroplastics and the number of microplastics in your table.
Count the total number of anthropogenic debris in your transect to get a total count.
ADD YOUR DATA TO THE TRASH TRACKERS MAP
Add your data to this GOOGLE SHEET in a new row. Use a new row for each transect sample that you collected.
In about one day, your data will be automatically added to this MAP. Check the map to explore your your data visually and to compare it with data submitted by other students.