Sand was collected on Kauai beaches from 28 October to 6 November 2009. It was placed in containers for use by others, but one film cannister full from each beach was scooped from the upper intertidal. The contents were placed in a glass bowl, water was added to cover as in previous beach studies. The surface of the water was then scanned with a 10X magnifier for any plastic that floats out from the more dense sands, rocks, shells, and pieces of coral.
Sand was collected around the island, but most from windward side beaches. This was partly to see if I got the same results as another study talked about below.
Results:
A total of Nine beaches were sampled. Five of these tested positive for micro plastic in the samples taken this fall. The largest amount (44 pieces of small bits of mostly blue plastic) was seen in the sample from the southern end of Aliomanu Beach nearest the town of Anahola and the wonderful stop at Duane's Ono Charbroil Burger stand where the Shoyu Burger shines.
I gotta add here that Duane's uses cardboard, paper, and pretty much no plastic. Mahalo Duane's.
Plastic was found at these beaches:
Haena (1 piece)
Papaa Bay (9 pieces) For you fans of movies, the site of Harrison Ford and Ann Heche crashing in Six days and Seven Nights.
Aliomanu North (9 pieces of plastic)
Aliomanu South
Anahola North (3 Pieces of Plastic)
Plastic was not seen in the following beach samples:
Lumahai (But you must see the beautiful sparkling peridot that does make up a lot of this sand.) Lumahai is a very powerful place with high wave energy and no protecting reef. The day the samples were taken, the front of the beach had been carved so that a ten foot vertical wall of sand faced the ocean as the tide dropped. The day before, this same beach front was a gentle, gradual slope. The "upper intertidal" is a wide swath of wind and wave swept beach where many people die each year when a sudden wave washes them away. Still, it is one of the best boogie board beaches and local kids love this spot. So do barracudas, common inches from the edge of the beach.
Anini (Anini Beach rests within the protected rim of coral reef that is the longest in the Hawaiian Islands. This reef protects the beach from a lot of wind driven wave action and deposition of plastic and other objects is far less than other, more exposed beaches)
Moloa'a Bay southshore (Moloa'a is the first place I ever saw or recognized seeing micro plastic. It was in the form of nurdles, most probably washed away from a cargo ship enroute to becoming some kind of plastic product. This was several years ago when most of us thought most micro plastics floated ashore from ships. Moloa'a has some pretty high energy wind driven waves, but the bay is far more protected from drift moving up and down the island than, say, Aliomanu.
Port Allen pocket beach (Port Allen is on the south side of the island. A lot of debris accumulates here, but not so much as on the windward side of the island.
One additional piece of small plastic was observed in the samples taken. Remember Jacks? The game with the little playing pieces you place on the floor, then scoop up after bouncing and catching a ball? When my daughter was young, these were made of metal. Now, they are plastic. I scooped up a yellow Jacks (Jack?) in one of the sample......
Discussion:
It is not surprising to find micro plastic in Kauai beaches, especially in the fall when winds increase and movement of material accelerates along drift cells. Kauai rests within the North Pacific Central Gyre where floating plastic is well documented in the literature (Moore et al 2001; Pichel et al 2007 - complete refs available if you are interested) and now, in popular press (Rolling Stone October 29, 2009 has a pretty good account and many links on this site will take you there, literally).
I did not see micro plastic in the samples at Moloa'a although there was visible micro plastic here and there on the beach, noticed while coming and going on several occasions. In past visits to Moloa'a the beach was littered with nurdles and a lot of large plastic. This is one beach where locals have spent a lot of time cleaning up the beach. Mahalo Kauai!!!
In general all beaches of the island were cleaner than I have seen in twenty years of "casual" observation. Recent large scale beach cleanups have taken place. This rids the beaches of plastic that eventually is ground down into smaller pieces, but as pointed out in studies (Corcoran et al 2008 is focused on some of these same beaches), the micro plastics enter the beach in many ways. Low density plastic pieces can float onto the beach, but they break into small pieces as they are mechanically broken down along the beach.
The larger concentrations of microplastics seen in my study are similar to those of Corcoran et al. Their study suggests that plastics enter these beaches (all high concentration of plastics on the eastern shore of Kauai) more than others because of the way ocean currents wash against and along the shores of the island. They also suggest that more plastic accumulates here, but my experience suggests that large volumes also accumulate from Port Allen to Salt Ponds at Hanapepe along the south shore. I did not get out to Polihale along the west shore where no plastic was found in the Corcoran study, but where it would be expected mainly due to the long, unprotected sandy beach aka Barking Sands. More study needed?
The important thing here seems to be that micro plastics are a major part of at least the eastern shores of Kauai. Beach cleanups have helped reduce local supplies of large plastics that break down as they move along the shore. But plastic reaches the island in many ways and will continue to fall on the shores from the Pacific.
I talked with many people while collecting sand and while surfing, fishing, and just being on island. No one I talked with was aware of micro plastics. No one knew anything about Papahanaumokuakea, Pihemanu, or the death of marine life by plastics. This included locals and visitors. But as I left island, I had two nice conversations in the Lihue Airport. I was having my picture taken with Fred by a big window display about Papahanaumokuakea. People were, as always, taken by Fred and I pointed out the display to them. While they absorbed information about the National Monument, I showed them Fred's leg band. In Memory of X310 these people now know a lot about ocean plastics and the great place called Papahanaumokuakea Marine National Monument. Funny how a little monkey can teach so much to people like them and even the nice lady at the car rental check out...........Thanks for all your help Fred and for taking me out of the water long enough to collect these samples.
Posts
