When people are asked to think about the word “health”, thoughts automatically turn inward. They think of their heart or their joints, liver or lungs, associating health with the internal environment, our “innards”, all those organs and vessels. But the external world is a critical component of health. Our environment has an obvious effect on our health, especially when toxins are present. A source of these poisonous substances not often considered is that of the seafood consumed by so many.

Recent investigations have shown that humans are being exposed to, and potentially affected by, plastics that have become part of the marine food chain. Only recently has plastic pollution in the oceans become a real concern amongst governments, public service groups, and the general public. In 2013, Americans produced 254 million tons of trash. It works out to roughly four and a half pounds of solid waste produced per person per day, at least in the U.S. Plastics represent approximately ten percent of this mass.

Plastics have become an integral part of human society in this age of man. Remember the Stone Age? This may be the Plastic Age. They are certainly important in health care. Some particular benefits in medicine have been their versatility in combination with low cost. This has allowed for mass production and single-use products, clearly more hygienic, disease-preventing. Needless to say, the importance of plastics to society at large is tremendous

Plastic, although invented in 1907, went into real production in the sixties. At this point, Americans are producing more plastic trash than ever, and only a small percentage is recycled. Most of the plastic in our oceans came from the land. And there is a lot of it. Over the last few decades, mankind has managed to dump many tons of garbage into the oceans. The total amount of plastics produced in the world in the first decade of this century is equivalent to the total world production in the entire century before.

Plastic is everywhere, ubiquitous, nearly omnipresent. And because we want these materials to hold up, they don’t break down. This is a critical part of this topic: plastic’s longevity. It takes thousands of years to decay. Unfortunately, plastics, over time, typically leach out the toxic substances they are composed of. These products are known to persist, polluting the environment for decades, centuries, even millennia. Some end up in landfills. When this happens to plastics, it interacts with water and forms dangerous chemicals. These chemicals can seep underground, thus degrading the water quality. Marine life and wildlife are becoming poisoned, with these toxins entering the food chain. Invariably, this will mean human consumption, threatening human health.

In the most polluted places in the ocean, the mass of plastic exceeds the amount of plankton six times over. The largest of these, The Great Pacific Garbage Patch, is located in the North Pacific Ocean and is larger than the state of Texas, although similar garbage patches can be found in the Indian and Atlantic Ocean. These islands form as the currents carry the plastic, collecting where the currents meet.

Plastics reach the ocean by being blown into the water, picked up by tides, or dumped off platforms and ships. There they gradually break down into ever-smaller pieces termed micro-plastics, due to the action of sunlight exposure, oxidation, the physical action of waves and ocean life. These micro-plastic pieces are recognized to be the most abundant type of plastic in our oceans. Microplastics can now be found almost everywhere looked for, from the beaches and shore-lines to the open ocean, in varying concentrations.

If the formation of these micro-plastics wasn’t enough, studies have revealed plastic tends to take up certain persistent, toxic substances present in trace quantities in almost all bodies of water. Consequently, the components of plastics, as well as the chemicals they absorb, can be consumed or taken up by sea life of all sorts. How concerned should we be about marine plastics as far as human health goes? Owing to the many additives contained therein, plastics pose a number of potential human health and environmental risks. Certain components of plastic will affect the human endocrine system, wherein any level of exposure, no matter the route, may be potentially harmful. Of principal concern are hormone-disrupting properties, some of which cause problems with fertility.

We need to know whether consumption of plastic debris by marine organisms translates into toxic exposures for people who eat seafood. One question that can’t yet be answered concerns the toxicity of the microplastic particles themselves. Even without considering the chemicals taken up by plastic, these particles can induce abnormal immune system responses, alter gene expression, and cause cell death, amongst other adverse effects. They can pass through the placenta and the blood-brain barrier and can be taken up by the gastrointestinal tract and lungs. And we do not yet have a test that measures human tissues for microplastics.

Those plastic components of known adverse health and ecological effects should be removed from the manufacturing process. Some examples include BPA found in polycarbonate food containers and DEHP from medical equipment. The lack of biodegradability, even when considered safe from a toxicological perspective, also demands change. The next-generation of substances will be carbon-neutral monomers that are nontoxic and will be degradable at a rate sufficient to prevent the ongoing accumulation of plastic debris in terrestrial and aquatic environments.

We can’t yet say how much plastic, in all its varied forms, is in the ocean. The studies performed to date aren’t able to tell us. We do know that plastic has become almost omni-present on our planet. It has been found on the most remote beaches, collected to form these floating islands, and has been discovered in the bodies of all manner of living creatures, from fish to birds to whales. We do know enough to say it is contributing to the on-going, persistent accumulation of toxic substances in the human diet.

The continued production of these durable materials, of limited recyclability, for use as short-lived consumer products is unsustainable. The earth is a closed system. To a single individual, it seems immeasurable, without boundaries. But at this point in human development, we know otherwise. The human population has continued to increase, climbing irrevocably towards eight billion people, nine billion predictable. Can our planet support these numbers, or will we poison ourselves in the process?

Typically, the common response to questions of this sort center around the notion technology will save us. Some new invention, or radical new process will enable us to survive and thrive. But with the increasing production and discharge of these substances into this closed system, at some point, past or future, these enduring materials will impact human health. This is in addition to the documented ecological effects. These are substances the human body is not equipped to deal with. What consequences will there be as they filter through the complex system which is Earth’s ecology. Will we see a decrease in fertility or an increase in cancer rates as a result? Or are we already?

Many scientists, along with many of the general public are demanding the development of smarter and safer materials for future use. We need to create the next generation of plastics, making them more biodegradable, with a markedly shorter half-life. This will means they won’t accumulate in the oceans, along with less absorption of toxic chemicals. We can’t shield people from all possible exposures, but perhaps we can produce safer chemicals. Hopefully the environment and our health won’t suffer too much in the meantime.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with a move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments atdrcmclean@outlook.com.