Dangers of Bioaccumulation, The

Dangers of Bioaccumulation, The

O’Rourke, Morgan

In today’s world, any responsible company is well aware of the risks associated with pollution. A host of laws regulate the environmental impact of business’ operations, and keeping track of compliance with these regulations is a given for any risk manager. Of course, it is obvious that smokestacks spouting fumes and drums filled with industrial waste represent environmental risks that must be handled, but sometimes risks that have never been considered can surprise an organization and present a litigation nightmare that no one was prepared for.

In 2002, the United States Geological Survey completed a study that found that more than 80 percent of U.S. streams contained trace levels of man-made pharmaceutical and personal care pollutants. This included antibiotics, prescription drugs like Prozac and Zoloft, insect repellants, detergents, acetaminophen, caffeine, steroids, hormones and plasticizers. This contamination was not the result of illegal dumping by an unscrupulous company. Rather it was the natural result of human excretion and run-off into wastewater and sewage. Since most wastewater plants are not designed to screen out these chemicals, they were able to enter the environment.

Studies have shown that not only are these and other chemicals appearing in waterways, but they are being absorbed by humans as well. In the Second National Report on Human Exposure to Environmental Chemicals released in early 2003, the Centers for Disease Control and Prevention (CDC) measured the exposure levels of 116 chemicals in blood and urine samples from 2,500 participants and found mercury, lead, uranium, dioxins, PCBs, pesticides, herbicides, phytoestrogens, and cotinine, a by-product of nicotine.

Although the presence of these chemicals has been studied and verified, current research has yet to address their health effects, which remain, for the most part, unknown. Both the CDC report and a recent report from the United Kingdom’s Royal Commission on Environmental Pollution, however, acknowledge this as a vital area for further study. The Royal Commission’s Report found that the potential risk of these new contaminants was so high that it not only called for a radical change in the way they are assessed for safety but offered solutions to improve assessment practices in the United Kingdom. “Given our understanding of the way chemicals interact with the environment,” says Commission chairman Tom Blundell, “you could say we are running a gigantic experiment with humans and all other living things as the subject.”

Testing may prove to be a daunting task, however, since researchers are dealing with an estimated 75,000 chemicals used in the United States and 30,000 chemicals used in the European Union that have not been subject to any testing on their health effects.

There are studies on animal populations, however, that are beginning to make disturbing conclusions. Recently, researchers from Baylor University discovered the presence of fluoxetine, commonly known as Prozac, in the tissue of fish in a Texas stream. Meanwhile, aquatic toxicologists in a University of Georgia in Athens lab, found that low levels of anti-depressants such as Prozac, Zoloft and Paxil can inhibit development in certain species of fish and delay metamorphosis in frogs. So there seems to be an effect, at least for these smaller creatures. A logical conclusion could suggest that humans are not in danger since the concentrations of these chemicals, while proportionately large for fish or frogs, are just not high enough to affect us. So, are these findings even theoretically applicable to humans? The answer is as sobering as it is simple: yes.

The Science of Bioaccumulation

Certain chemicals affect living organisms through the process of bioaccumulation, which is the increase over time in a chemical’s concentration in a biological organism compared to the chemical’s concentration in the environment. Not every chemical will bioaccumulate since it is dependent on a variety of factors related to the uptake, storage and excretion processes of the organism as well as the nature of the chemical itself. This is a normal and essential process when involving important nutrients such as vitamins, minerals and amino acids but it is of great concern to toxicologists when involving potentially harmful man-made chemicals. Of even greater concern is the tendency of some chemicals to accumulate in higher and higher concentrations the further they move up through a food chain. This process is known as biomagnification.

In an example cited by Michigan State University’s Institute for Environmental Toxicology, a study found the concentration of DDT in soil levels to be 10 parts per million (ppm). Concentrations reached 141 ppm in earthworms, however, and 444 ppm in robins. So if a stream is contaminated and algae in the stream are eaten by insects, which are eaten by fish, which are eaten by humans, it is possible that chemical concentrations that were initially very minute could have increased to harmful levels at the top of the food chain, causing a significant risk to humans.

Unexpected Risks

In the past, bioaccumulation has been an issue with pesticides such as DDT and hazardous industrial by-products such as clioxins and PCBs. Fish conlaminated with high levels of mercury have received attention for the health risks they pose. But these materials are known poisons, so it is no surprise that they would attract special notice. More innocuous materials, however, can also present problems.

Take selenium, for example. It is an essential nutrient for humans and animals that activates important antioxiclant enzymes and is thought to promote a healthy immune system. The FDA recommends a dietary allowance of 55 micrograms a day, which can be obtained through grains, cereals, seafood and animal organs.

Selenium is also a by-product of copper refining, which can release the mineral into the air and water. As plants and animals consume selenium-containing water and breathe selenium-containing air, concentrations accumulate, leading to potentially harmful effects. Livestock develop what is known as “blind staggers,” a disease characterized by impaired vision, aimless wandering, reduced food and water consumption and paralysis. Long-term selenium consumption can result in “alkali disease,” which results in hair loss, deformation and sloughing of hooves, erosion of joints and bones, anemia, and heart, kidney, and liver problems. In humans, high amounts of ingested selenium can cause hair loss, deformed nails, tooth decay, fatigue, liver and spleen damage, and loss of feeling and control in extremities. Other selenium compounds have been found to cause nausea, headaches, dizziness, rashes, respiratory problems and even cancer. So while it is a necessary nutrient, bioaccumulation can create elevated levels of selenium that are toxic to animals and humans.

It is possible that, like selenium, many of these unstudied chemicals and pharmaceuticals that have been appearing in the environment could have harmful effects at certain levels. Something as seemingly innocuous as acetaminophen can cause nausea, vomiting, exhaustion and even liver damage if taken in excessive amounts. An overdose of Prozac can cause an irregular heartbeat, fainting and severe dizziness. Even the side effects of normal usage include nausea, anxiety, loss of appetite, insomnia, drowsiness and sexual dysfunction. Only further research will determine if the environmental presence of these chemicals will lead to bioaccumulation and similar harmful effects.

Unanswered Questions for

Risk Managers

Basic health concerns aside, there are corporate concerns that risk managers may need to consider. For instance, should these environmental contaminants prove harmful, what are the legal ramifications for the company that produced the chemical? It is unlikely that a drug company would have foreseen a long-term pollution-related risk of their product since it is likely that few clinical tests take frogs and waterways into account. As we have seen with asbestos-related suits, liability can exist without intention to harm and the potential for a jury to award significant damages is all too real.

Further complicating the issue is the fact that this is a problem that cannot necessarily be confined to a specific location so assigning responsibility to any one party could be difficult. Contamination that began in one area could easily appear in an entirely different region miles away. Tainted water could be used to irrigate a field, producing contaminated crops that are exported to far-flung locations. Animal migration patterns can spread concentrations of Zoloft or Tylenol, for instance, to places where the manufacturing or consumption of such pharmaceuticals is nonexistent. Therelore, it might be very difficult to find the source of the contamination and the resulting target of prevention efforts (or lawsuits).

The reality is there may be little that can be done at this point to ward off any problems. Wastewater filtration systems can be upgraded (at a significant cost) to remove these chemicals, but what of the chemicals that have already entered the environment? Has the damage already been done? Or is this a developing situation that will only gel worse if prevention measures are not instituted?

As research begins to study the effects of these pollutants, many of these questions will be answered. In the best-case scenario, if little or no ill efiecls are discovered, the debate will turn out to have been for nothing. But if research does not come to such a positive conclusion, the fallout could be powerful and far-reaching. Risk managers who have monitored the issue and considered the corporate risks will be ahead of the game.

Find More:

“Risk Reporter: Pesticide Exposure”

RM October 2002

Archive at rmmag.com

Morgan O’Rourke is RM’s managing editor.

Copyright Risk Management Society Publishing, Inc. Mar 2004

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