Plastics Threaten the Ocean
The first successful man-made plastic was Bakelite, introduced in 1910. In the 1930s, plastics development progressed to the point that they were widely used by the military during World War II. But it was not until the late 1960s that production dramatically increased to supply global markets. Replacing metals and glass in many applications, plastic was cheap to produce, disposable, and durable. It seemed there was almost no limit to its uses. Today, annual global production is more than 328 million tons and increasing more than 4 percent per year.
Unfortunately, little of the massive amount of plastic produced is recycled. Consider those one-use supermarket shopping bags. Their average lifetime is measured in hours from use to disposal. 500 billion are used annually worldwide, and only 5 percent are recycled. Then there are water bottles. Americans use 48 billion a year, and few are recycled.
The vast majority of discarded plastics remain on land, but the World Ocean—home to 80 percent of life on our planet—is downstream from all human activities. About 80 percent of plastic in the sea comes from the land. It is estimated to be 9.5 million tons per year and increasing. In 2016, a group of experts predicted that by 2050 the weight of plastic in the oceans would exceed that of the fish.
Stunning ocean images show massive patches of floating plastic, but most of it is in the form of microplastics, less than 0.2 inches in size, distributed throughout the oceans’ depths. In 2017, researchers even found plastic in the Marianas Trench, the deepest place on earth. A recent report estimated the number of microplastic bits might be as high as 52 trillion, 500 times more than the number of stars in our galaxy.
What are the fate and effects of plastics in the oceans? Organic material is subject to biological decomposition from the effects of the sun and bacteria. While plastics also are affected by sunlight, mechanical weathering is more important. Motion breaks them down into smaller and smaller pieces. As they are modified they can release toxic compounds. Some attract colonizing organisms that concentrate harmful compounds absorbed from seawater.
Plastic microbeads are a more recent pollutant. These tiny spheres are used to enhance cosmetics, toothpastes, and cleansing products. Annually, billions are produced. Because of their size, water treatment facilities cannot filter them out before the effluent reaches the ocean. Easily ingested, they are retained by marine life and passed up through the food chain by prey-predator activities. Since mankind is the top predator, those beads return to us in the seafood on our dinner plates.
On the macroscale, plastics’ effects on marine life are more evident in those tragic pictures of marine creatures crippled by plastic packaging materials or entangled in fishing nets. Often they see these materials as food and ingest them. They feel full but get no nutrition, resulting in gradual starvation.
Schemes have been proposed to physically remove plastic pieces from the oceans’ surface. Nature helps by concentrating it in the “garbage patches” in the five major ocean circulation gyres in the Pacific, Indian, and Atlantic Oceans. By weight 60 percent of this trash consists of lost/abandoned fishing nets, lines, and the floats that support them.
While physical removal of these materials can have some impact, it may be more “feel good” than effective. A better idea is to remove plastic in coastal areas where surface plastics are more concentrated and easier to harvest.
In the past two years, some governments have begun to take this problem seriously. Indonesia is the second greatest source of plastic in the sea. (China is by far number one.) Jakarta has initiated an eight-year program to reduce plastic pollution by 70 percent at a cost of $1 billion per year. Several nations—including the United States, Canada, and Great Britain—already have banned the use of microbeads.
In 2016, the United Nations Environmental Program organized the Clean Seas Program to reduce the flow of plastics into the oceans by 2022. Ten nations have now signed on, including the major polluter nations. Regrettably the United States (ranked number 20) has not yet joined.
The commercial slogan “diamonds are forever” could apply to the persistent, indigestible plastics in the sea. But the solution lies not at sea but on land, where it is essential to develop a global culture that emphasizes recycling, production of environmentally friendly plastics, and development of other environmentally friendly materials to replace plastics.
Don Walsh, a marine consultant, is a retired naval officer and oceanographer. During his naval career, he served at sea in submarines and ashore in ocean-related research-and-development assignments.