Every building site is first excavated for the foundation. A recent inspection at a site during excavation was shocking to me as we found well below the ground, at depths of almost a meter below the top soil, compacted plastic mixed well into the soil. The plastics are of all different types — small bits of plastic packaging, a few small-sized shopping bags and of course the fragments of PVC pipes — at the end of the day all different versions of plastic — somewhat eroded by the soil and by being buried under the soil for an extended period of time.
Around the same time there were readings coming in from Ventana — The Monterey Bay Aquarium Research Institute’s multimillion-dollar machine perched atop a research vessel all the way in California. “It’s a massive underwater robot,” explains Kyle Van Houtan, chief scientist with the Monterey Bay Aquarium, which collaborates with MBARI. Ventana has been trawling the ocean up to 3,000 feet deep into the Bay in search of plastic. While there is a lot of knowledge regarding plastic on the ocean surfaces and many popular articles and documentaries on the Great Pacific Garbage Patch — there has been little done to understand plastic contamination in the depths of our oceans.
“What we found was actually pretty surprising,” Van Houtan says. “We found that most of the plastic is below the surface.” More, he says, than in the giant floating patches. And also to their surprise, they found that submerged microplastics are widely distributed, from the surface to thousands of feet deep. The further out from the coasts Ventana dived, the more the microplastics she recorded — suggesting this is debris from all over and not just the coastlines. The readings further confirmed that even plankton and small tadpole like organisms from the deepest depths of the ocean are all showing microplastics in them. Fish and red crabs that never come to the surface of the water were also showing microplastics confirming that plastics have entered our food chain through marine animals that people eat.
Back on land, there is very limited research into microplastics in our soil and the impact of this phenomenon is not fully understood. Microplastics have been found in the digestive systems of earthworms and other soil worms. Some worms experience stunted growth, and others die. These worms and biota are crucial to the health of our soil, so keeping microplastics out of our soils is an essential step in keeping soils healthy and productive. Plus, anything that eats these worms (birds, frogs, rodents etc) will also ingest microplastics and, in turn, risk experiencing these negative effects.
Research has yet to show any effects of microplastics on soil microbes or plants. However, there are concerns that if microplastics continue to break down into smaller and smaller fragments they could become nanoplastics. Plants can absorb nanoparticles and they can reach as far as a plants leaves. This obviously raises concerns of plastic being able to enter our food chain through agriculture as well. So there we have it — plastic has sunk to great depths of the planet — both on land and in the sea — we need to be aware and take steps to protect ourselves, before it starts running in our veins completely.