This is an extract from dissertation on Biomagnification:
Every year millions of people get cancer and it’s a major problem in the United States that many people do not like to think about because of how it could impact their lives! Some of these cancers can be linked to a process known as biomagnification, or biological magnification. Biomagnification is a result of bioaccumulation and they are related, yet very different (McGrath 78). These two terms, biomagnification and bioaccumulation, are processes that are causing more damage to the environment than most people think. There are many pollutants that affect these processes and they are commonly dumped into waterways or released into the air. Some of these common pollutants are DDT, PCBs, Polynuclear Aromatic Hydrocarbons (PAHs), lead, and mercury. These pollutants are catastrophic for Mother Nature, as well as humans. Biomagnification is a serious dilemma for life on Earth because it only takes a few pollutants to eventually concentrate to very high levels of toxicity in animals, including humans, after they have consumed lower-level organisms that have been previously contaminated with harmful pollutants.
There are many ways that contaminants can enter ecosystems on land, in water, and in air. Contaminants come from many sources like rain, pesticides, atmospheric deposition with rainfall, and discharges to water, usually by larger corporations trying to save money (McGrath 78). Every year, millions of gallons of pollutants are dumped into waterways all over the world, both legally and illegally (Weiss 35). Once the pollutant enters the waterway it will persist in the environment because of the water cycle. Many people do not know just how dire certain pollution is and they should be educated on how to prevent it for the sake of the Earth. Toxic materials, like cyanide and selenium, do nothing but harm our ecosystems and our way of life. They bio-accumulate, or build up, in smaller organisms and can concentrate in a more harmful process, known as biomagnification. The reason why these contaminants can build up is because they can’t be excreted or metabolized easily by most organisms and therefore, they are accumulated in high levels (McGrath 78). Moreover, almost all synthetic chemicals and radioactive materials can’t be diluted or broken down by natural processes (McGrath 85). Bioaccumulation refers to how pollutants enter a food chain, whereas biomagnification refers to how pollutants tend to concentrate as they move from one level of the food chain to the next (Bioaccumulation). Even though there are definite differences in these processes, they will always be linked by the destructive nature of menacing pollutants.
One such pollutant is the iniquitous DDT, standing for dichlorodiphenyl-trichloroacetic acid, which is a chlorinated hydrocarbon that has widely been used as an insecticide. Chlorinated hydrocarbons, like DDT, are a diverse group of synthetic compounds of carbon, hydrogen, and chlorine, which are used mainly in pesticides (McGrath 204). In World War II, DDT was a valuable insecticide used by the United States Armed Forces; it was sprayed on clothing and dusted on the bodies of soldiers, refugees, and prisoners to kill body lice and other irritating insects (Enger 240). It was important in this aspect because it helped maintain the health of millions of people by preventing typhus fever, and it was a valuable tool, also, because it aided tremendously in achieving victories (Leary 1). Around the Second World War DDT production in America increased from zero to three million pounds per month, in less than just two years (Leary 2). The greatest use in the United States was seventy-nine million pounds in 1959, and its maximum annual production was close to two hundred million pounds in 1964. Its peak production was in 1970, when almost three hundred and eighty million pounds were manufactured globally (McGrath 205). DDT has a major effect on nature and it needs to be completely eradicated.
DDT’s effect on the food chain is immense because it’s soluble in fat and it’s an exceptionally stable compound. In addition, once it is present, it remains effective and stays around for a long time (Enger 241). Because DDT is soluble in fat, it can easily be stored in the fat deposits of insects and small organisms where it can bio-accumulate. Cox, an expert on DDT states, “Ten milligrams of DDT is about the size of the sharpened tip of a pencil and is the minimum concentration to be considered effective enough to bio-accumulate sufficiently to be lethal,” (Leary 2). Its use was originally very effective; however, as time passed, many species of insects formed an immunity to it and it began to kill numerous beneficial species of insects as well. Instead of just harming the pest species, it bio-accumulated in smaller organisms, bio-magnified throughout the food chain, and began to kill larger, non-target species as well, such as predatory birds (Enger 241). A possible reason why many species of insects were able to form an immunity to DDT is because the more complex an ecosystem is, the more likely it is to recover after being harmed or disturbed (Enger 240). The insect community is definitely complex and it’s true that communities that have a wide variety of organisms and a high level of interaction are more resistant to disturbances, such as pollution, than those with fewer organisms and little interaction (McGrath 85). DDT should have been researched more and never should have been manufactured, at least not on a global scale.
DDT was first synthesized in 1874 (McGrath 204). Paul Muller, a Swiss scientist, discovered it’s insecticidal qualities sixty-five years later in 1939. He later won the Nobel Prize for his research on the uses of DDT in medicine in 1948 (McGrath 205). The use of DDT has been especially important in reducing the number of incidents of malaria, which has always been a detrimental disease in warmer climates. On the other hand, it still retains more damaging effects than good ones, such as accumulating in water and air ecosystems (McGrath 204). Bioaccumulation occurs easily with DDT and other chemicals because it is long-lived, mobile, fat soluble, and biologically active (Bioaccumulation). Biomagnification of any chemical wouldn’t be possible without the bioaccumulation of that chemical, first.
An example of biomagnification that resulted from bioaccumulation occurred with DDT. Studies showed that eagles, falcons, pelicans, and other predatory birds were affected with such high levels that their eggshells became so thin that they broke almost instantly when the mother sat on top of them (McGrath 79). Since these birds are at the higher end of the food chain they were affected with high concentrations of DDT. This is because they would eat a lot of contaminated fish that started out with hardly any DDT in them at all, and over time, it bio-accumulated. These birds also had a large population decrease due to a decrease in clutch size, the number of eggs laid. There was also pathological parental behavior and the male birds became feminine-like because the excess DDT acted as an ‘estrogen’ chemical in their bodies. Once scientists knew what was causing the population decrease they banned DDT.
Credit for sounding the warning about DDT and biomagnification usually goes to Rachel Carson who wrote Silent Spring in 1960 (Bioaccumulation). Research efforts were near the eighty-two billion dollars expended on the atomic bomb. There were even plans to put it in paints, soap powders, floor waxes, and other articles (Leary 3). Even though it is still manufactured and used in many parts of the world, including Mexico, DDT was banned in the United States in 1972. Since, there has been a dramatic increase in the population of several predatory bird species (Enger 240). DDT is not the only harmful pollutant because, in actuality, there are hundreds.
In the past few years polychlorinated biphenyls have been creating a large threat to some animal communities, especially those near the North Pole. Polychlorinated biphenyls (PCBs) contain over two hundred and nine individual compounds with varying toxicities (McGrath 129). Also, there are around two hundred known compounds that qualify as PCBs (Amdur 49). Ironically, PCBs weren’t supposed to be released into the environment because scientists knew what damage DDT did and they did not wish to repeat that scenario with even more threatening synthetic compounds (Polychlorinated 363). Yet today, PCBs are still widespread throughout the environment. They exist worldwide in numerous places such as water, ocean sediments, and especially fish (McGrath 130). There are some major problems now because of the hasty and careless polluting of PCBs into the environment and it has been going on for almost seventy years.
Since its production began back in the 1930’s one and a half billion pounds of PCBs have been manufactured in the United States alone. Numerous amounts of these chemicals have found their way into the air, waterways, river sediment, and even certain foods, like fish and poultry (Polychlorinated 364). Like DDT, they are very stable in the environment and persist for many years. Throughout many food webs they are continuously recycled again and again. A number of PCBs were used in many common products: coolants, lubricants, hydraulic fluids, inks, plastics, tapes, paints, glues, waxes, and polishes. However, the major use for these compounds was in insulators for electrical transformers (Bioaccumulation). The reason for this is because of its properties that make its mixtures colorless, viscous fluids that are relatively inert chemically and nearly insoluble in water. These properties make them resistant to heat, light, fire, and particularly electricity (Amdur 49).
Scrapped electrical transformers create major hazardous waste problems because PCBs leak into nearby waterways (Weiss 31). To this day, more than one billion pounds of PCB fluids remain in transformers and other electrical equipment (McGrath 206). In 1970, its production was limited to cases where satisfactory substitutes weren’t available and in October of 1977, its manufacture was halted (McGrath 206). However, since April of 1979, when the EPA banned its manufacture, there have been substitutes found for almost all of its former uses (Enger 241). With all this excess of PCBs, scientists needed to find a way to not only substitute, but to entirely purge them from the face of the Earth.
Substituting PCBs doesn’t stop the threat of biomagnification and scientists know this and they’re trying to come up with ways to completely eliminate them. Three years after PCBs were banned an incineration ship named “Vulcanus” was allowed by the EPA to incinerate over three and a half million gallons of PCBs. Waste Management Incorporated, of Oak Brook, Illinois, built this ship and equipped it with two incinerators that were capable of burning four thousand gallons of waste per hour. Afterwards, they calculated that it had only destroyed ninety-nine percent of the PCBs; nonetheless, it was theoretically intended to destroy one hundred percent of the PCBs, and this percentage upset the EPA because of bioaccumulation (Weiss 35). Gladly, a new method has been adopted recently that eliminates PCBs even better than the massive incinerators. Scientists have developed microbes that devour PCBs and neutralize Agent Orange and then die when their work is complete (Amdur 78). As one may presume, PCBs play a major role in biomagnification and need to be eradicated as soon as possible; it is possible!
Dangerous pollutants, such as DDT, PCBs, PAHs, lead, and mercury, get into the environment pretty easily. Big corporations looking to save money dump their wastes into unprotected waterways, and ultimately, everything suffers. Once a pollutant is in the water cycle, it can travel very far distances easily, which makes bioaccumulation occur easier. For example, PCBs have been known to travel thousands of miles from their sources, and over time, they accumulate to fairly high intensities in various ranges of organisms (McGrath 129). Global contamination of bio-accumulated pollutants in organisms is made possible by their characteristics. Ironically, human influence is usually indirect, and habitat destruction is the main cause of extinction and endangering of species (Enger 240). Perhaps one of these days biomagnification will be the main cause of extinction if it isn’t stopped soon. If it isn’t stopped then human health will be affected just as much as any of the other animals.
Throughout the last decade there have been many cases of diseases, cancers, and other long-term sicknesses, as well as other diminutive cases. Behind the scenes, bioaccumulation and biomagnification, with certain pollutants, are running some of these infirmities. For example, children exposed to PCBs while in the womb were smaller and had much slower brain development than children that weren’t exposed (Health). It would be surprising if the parents of those children were exposed to PCBs because they are known to impair reproduction (Bioaccumulation). Getting exposed to PCBs isn’t very difficult considering all you have to do, basically, is fish. Almost everyone has PCBs in their bodies, and people who eat a lot of fish and seafood, have higher concentrations than people who don’t. PCBs have been measured in human blood, milk, and fat tissue from people all over North America (Health). Whenever people eat organisms higher in the food chain they are increasing their risk of getting chemical pollutants as part of their meal also. Lab mammals fed PCBs have suffered: enlarged livers, gastrointestinal lesions, loss of hair, and much more (Polychlorinated 363). Various people all over the world have reported cancer, liver ailments, birth defects, skin lesions, damage to the eyes, and damage to the lungs, when they were exposed to PCBs (Weiss 31). Factory workers have experienced nausea, dermatitis, dizziness, bronchitis, and severe eye irritation, after being around PCBs (Polychlorinated 363). All the animals and people affected by these pollutants in the past can relate to why we, as a society, need to take charge and significantly reduce pollution.
In closing, biomagnification has the potential to be truly deadly. Millions of people get cancer every year and it’s a major problem that many people have to face sooner or later. Some of these cancers are caused by biological magnification, which is a result of the bioaccumulation of pollutants in an organism. There are many pollutants that affect these processes such as DDT and PCBs. These pollutants cause unprecedented amounts of damage to the world by bioaccumulation and biomagnification. It’s a very serious dilemma because it only takes a handful of pollutants to eventually concentrate up to deadly levels of toxicity in all sorts of life. When the future gets clearer we will know if we have survived, but as long as we have the knowledge and the will, we can strive to overcome anything that Mother Nature hurls our way.