Biomagnification

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KARYA TULIS

BIOMAGNIFICATION

Oleh :

RAHMAWATY

DEPARTEMEN KEHUTANAN

FAKULTAS PERTANIAN

UNIVERSITAS SUMATERA UTARA

2010

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KATA PENGANTAR

Puji syukur kami panjatkan kepada Tuhan Yang Maha Esa, yang telah memberikan segala

rahmat dan karunia-Nya sehingga KARYA TULIS berjudul “Biomagnification” ini dapat

diselesaikan.

Tulisan ini merupakan suatu hasil pemikiran yang diharapkan dapat memberikan

informasi kepada pembaca mengenai Biomagnifikasi (definisi, bagaimanan terjadinya, dan

cara pencegahan).

Kami menyadari bahwa karya tulis ini masih jauh dari sempurna, oleh karena itu

kami mengharapkan saran dan kritik yang bersifat membangun untuk lebih

menyempurnakan karya tulis ini. Akhir kata kami ucapkan semoga karya tulis ini dapat

bermanfaat.

Medan, Maret 2010

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DAFTAR ISI

I. Introduction 1

A. Background 1

B. Objective of the Paper 2

II. Biomagnification: Definition and History 2

A. Biomanification, Bioaccumulation, and Bioconcentration 2

B. History of Biomagnification 7

III. Biomagnification Occurrence 8

A. Process of Biomagnification 8

B. Chemical can be Occurred biomagnification 10

C. Properties of Biomagnification Chemicals 12

D. Case Examples of Biomagnification 13

1. Biomagnification caused by DDT 13

2. Biomagnification caused by Mercury 15

IV. Prevent of Biomagnification 15

A. Pesticide-Producing Establishments 16

B. FDA Monitoring Program 17

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BY: Rahmawaty

I. Introduction A. Background

Ecology is the study of the interaction between organisms and their environment (Odum, 1971). Ecology is derived from the Greek root “oikos” meaning “house” combined with the root “logy” meaning “the science of” or “the study of”. Hence, ecology is the study of the earth’s households including plants, animal, microorganisms, and people that live together as interdependent components. The German biologist Ernst Haeckel first defined the word oekologie in 1866 in the context that we use it today. According to Miller (2006), the science of ecology is also concerned with the study of the interaction between organisms. It is also concerned with large environmental chemical processes like oxygen, nitrogen, and water cycles. Ecology is a new science which seeks to document and answer questions about connections in the natural world. Its concepts and ideas can explain the mess that we are now in.

With the knowledge of a small number of ecological concepts one can explain the causes of the major environmental issues we face today. What follows are the ecological explanations for six severe environmental problems: 1) Global Warming, 2) Pollution Poisoning, 3) Extinction, 4) Harmful Non-Indigenous Species, 5) Habitat Destruction, and 6) Overpopulation. Based on the six environmental problems above, the main focus of this paper is about pollution poisoning, especially about biomagnification. It is the one of the environmental problems/international issue that happened all over the world.

Biomagnification is an important concept in ecology, environmental science, and ecotoxicology. It says that the solution to certain types of pollution is not dilution, because food chains will concentrate the pollutant (http://en.wikipedia.org/wiki/Talk). Because of important to know and understand about environmental problem, especially biomagnification, this paper will try to explain about definition, history, process, Chemical can be occurred biomagnification, properties of biomagnification chemicals, cases of biomagnification and how to prevent biomagnification occurrence. Hopefully, this

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paper can increase our knowledge and give us the information about biomagnification.

B. Objectives of the Paper

The aims of this paper is giving information about definition, history, process, chemical can be occurred biomagnification, properties of biomagnification chemicals, cases of Biomagnification and how to reduce biomagnification occurrence.

II. Biomagnification: Definition and History

A. Biomagnification, Bioaccumulation, and Bioconsentration

To understanding about the biomagnification, there were two matters that also related, namely: bioconsentration and bioaccumulation. Therefore, in this paper also explained the different between biomagnification with bioconcentration and bioaccumulation.

1. Biomagnification

There are some definitions about biomagnification. One of the definitions in Environmental Protection Agency (EPA) glossary (2006), namely: biomagnification is the increase of tissue accumulation in species higher in the natural food chain as contaminated food species are eaten. The term biomagnification refers to the progressive build up of persistent substances by successive trophic levels, meaning that it relates to the concentration ratio in a tissue of a predator organism as compared to that in its prey (GreenFacts Scientific Board, 2006). Wikipedia dictionary also mention about definition of biomagnification, namely: biomagnification or biological magnification is the increase in concentration of an element or compound, such as dichlorodiphenyltrichloroethane (DDT, a type of pesticide) that occurs in a food chain as a consequence of food chain energetic and lack of or very slow, excretion or degradation of the substance. Biomagnification describes a process that results in the accumulation of a chemical in an organism at higher levels than are found in its food. It occurs when a chemical becomes more and more concentrated as it moves up through a food chain. The dietary linkages between

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single-celled plants and increasingly larger animal species (Extension Toxicology Network,1993).

Biomagnification is the tendency of pollutants to become concentrated in successive trophic levels. Often, this is to the detriment of the organisms in which these materials concentrate, since the pollutants are often toxic. Biomagnification refers to the tendency of pollutants to concentrate as they move from one tropic level to the next. Increase in concentration of a pollutant from one link in a food chain to another. This is a general term applied to the sequence of processes in an ecosystem by which higher concentrations are attained in organisms of higher trophic level in the food chain. The process by which xenobiotics increase in body concentration in organisms through a series of prey-predator relationships from primary producers to ultimate predators, often human beings. Biomagnification along a food chain will result in the highest concentrations of a substance being found at the top of the food chain (Maritta College, 2006).

Biomagnification is the bioaccumulation of a substance up the food chain by transfer of residues of the substance in smaller organisms that are food for larger organisms in the chain. It generally refers to the sequence of processes that result in higher concentrations in organisms at higher levels in the food chain (at higher tropic levels) (Fig. 1 and Fig. 2). These processes result in an organism having higher concentrations of a substance than is present in the organism’s food. Biomagnification can result in higher concentrations of the substance than would be expected if water were the only exposure mechanism. Accumulation of a substance only through contact with water is known as bioconcentration. (http://toxics.usgs.gov/definitions/biomagnification.html).

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Source: Is Mercury the Achilles Heel of the Restoration Effort?, South Florida Restoration Science Forum

(http://toxics.usgs.gov/definitions/biomagnification.html).

Fig 1. A hypothetical example of the biomagnification of mercury in water up through the food chain and into a wading bird's eggs.

Source: Ecological and Environmental Learning Services (2006) (http://www.eelsinc.org/id62.html)

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B. Bioaccumulation

An important process through which chemicals can affect living organisms is bioaccumulation. Bioaccumulation means an increase in the concentration of a chemical in a biological organism over time, compared to the chemical's concentration in the environment. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted. Understanding the dynamic process of bioaccumulation is very important in protecting human beings and other organisms from the adverse effects of chemical exposure, and it has become a critical consideration in the regulation of chemicals (Extension Toxicology Network, 1993). Bioaccumulation is a process where chemicals are retained in fatty body tissue and increase in concentration over time. (http://www.epa.gov/pesticides/glossary/).

Bioaccumulation refers to how pollutants enter a food chain; is increase in concentration of a pollutant from the environment to the first organism in a food chain. The accumulation of a chemical in tissues of an organism to levels greater than in the surrounding medium. Accumulation may take place by breathing, swallowing or dermal contact (Marietta College, 2006).

Bioaccumulation is a general term for the accumulation of substances, such as pesticides (DDT is an example), methylmercury, or other organic chemicals in an organism or part of an organism. The accumulation process involves the biological sequestering of substances that enter the organism through respiration, food intake, epidermal (skin) contact with the substance, and/or other means. The sequestering results in the organism having a higher concentration of the substance than the concentration in the organism’s surrounding environment. The level at which a given substance is bioaccumulated depends on the rate of uptake, the mode of uptake (through the gills of a fish, ingested along with food, contact with epidermis (skin)), how quickly the substance is eliminated from the organism, transformation of the substance by metabolic processes, the lipid (fat) content of the organism, the hydrophobicity of the substance, environmental factors, and other biological and physical factors. As a general rule the more hydrophobic a substance is the more likely it is to bioaccumulate in organisms, such as fish. (http://en.wikipedia.org/wiki/Talk).

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Bioaccumulation is the term bioaccumulation refers to the net accumulation over time of metals [or other persistent substances] within an organism from both biotic (other organisms) and abiotic (soil, air, and water) sources (Fig. 3). ( http://www.greenfacts.org/glossary/abc/bioaccumulation-bioaccumulate.htm)

Source: Wisconsin Department of Natural Resources ( http://www.greenfacts.org/glossary/abc/bioaccumulation-bioaccumulate.htm)

Fig. 3. An example of the Bioaccumulation

C. Bioconcentration

Bioconcentration is the specific bioaccumulation process by which the concentration of a chemical in an organism becomes higher than its concentration in the air or water around the organism. Although the process is the same for both natural and manmade chemicals, the term bio-concentration usually refers to chemicals foreign to the organism. For fish and other aquatic animals, bioconcentration after uptake through the gills (or sometimes the skin) is usually the most important bioaccumulation process (Extension Toxicology Network, 1993).

Bioconcentration differs from bioaccumulation because it refers only to the uptake of substances into the organism from water alone. Bioaccumulation is the more general term because it includes all means of uptake into the organism. Though sometimes used interchangeably with 'bioaccumulation,' an important distinction is drawn between the two. Bioaccumulation occurs within a tropic level, and is the increase in concentration of a substance in an individual's tissues due to uptake from food and sediments in an aquatic milieu.

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Bioconcentration is defined as occurring when uptake from the water is greater than excretion (Landrum and Fisher, 1999). Thus bioconcentration and bioaccumulation occur within an organism, and biomagnification occurs across tropic (food chain) levels (http://en.wikipedia.org/wiki/Talk).

B. History of Biomagnification

According to the ISI Science Citation Index, the first use of the term in the title of a peer-reviewed article was in Johnson & Kennedy (1973). However, the concept traces back to Rachel Carson's book, Silent Spring, published in 1962. In Chapter 3 of Silent Spring, he describes the process but does not name it as biological magnification. Interestingly, she focuses on terrestrial systems, but most research has been done in aquatic systems. Carson drew attention to the issue, and other ecologists and toxicologists examined its occurrence in many systems. As DDT, PCBs, mercury, and other substances were found through the 1970s to occur at strikingly high concentrations in the upper reaches of food chains, the concept of biomagnification of lipophilic substances became firmly established. It is presented in most introductory ecology and environmental science texts.

However, by the 1990s, some researchers began to question the roles of bioaccumulation versus biomagnification. For one thing, tissue concentrations of substances did not always increase uniformly with the tropic level (Landrum and Fisher, 1999). LeBlanc (1995) proposed that what is really bioaccumulation to different degrees is mistaken as biomagnification, because:

• Lipid contents of organisms increase with the tropic level

• Elimination efficiency of the substances decreases with tropic level (because the larger organisms have relatively less surface area to process and excrete substances, for their body size).

Thus the pattern of increased tissue concentration with higher tropic levels could be due to these differences in bioaccumulation. However, this proposal was based on rather limited data.

In 1990, Rasmussen et al. compared PCB levels in lake trout sampled from lakes with different numbers of tropic levels. Inputs to these lakes were small and relatively constant. The shorter the food chain in the lake, the lower the concentration of PCBs in the tissue of trout, which feed at the top of the chain (at least when they are large). This pattern is what is expected if biomagnification

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occurs. Additionally, they noted that the amount of PCB in tissues increased 3.5 times per tropic level, but the amount of lipids as a proportion of tissues increases much less, only 1.5 times per tropic level (Rasmussen et al., 1990).

III. Biomagnification Occurrence

A.

Process of Biomagnification

According to Miller (2006), the chemicals that enter the biosphere of living systems as a result of industrial processes are not all beneficial or natural. Plants for instance, need carbon and nitrogen, but there are many things that we have introduced into the world through industrial processes that are harmful to ourselves and other living creatures. We have produced dangerous chemicals that enter living systems and accumulate through the process of biomagnification, an increase in concentrations in living tissue as one travels up the food chain. Plants (organisms that can photosynthesize, thereby gaining energy from sunlight) are consumed higher up the food chain by animals that cannot photosynthesize, and animals higher up the chain then eat these animals. At the top of the chain is the apex predator that serves as an indicator species for the whole ecosystem: an interactive collection of numerous creatures. Food webs are more complicated than food chains in that the relationships are not linear, but rather a collection of many interconnections of food chains. The creatures that eat photosynthesizing bacteria may be eaten by many creatures, but these critters may also help in the digestion of larger animals which are connected in webs of relationships rather than a linear chain upwards.

Pollution enters these webs and chains at all levels and the concentrations increase up the many chains, until it could pose a threat to the animals at the top of the chain. Human society is often at the top of the food chain. The animals we eat can potentially pollute us. We have learned that what we have polluted the environment with can wind up on our dinner plate due to biomagnification. These pollutants can cause problems and cancer in human beings as well as creatures in the wild. For example, DDT had a deleterious effect on brown pelicans by interfering with the production of their eggs, which were too thin to incubate their young. When the use of DDT was diminished the brown pelicans made a recovery.

Pollution is also one of the factors that lead to the demise of wildlife populations. Through natural cycles we have all encountered and ingested

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dangerous chemicals. We need to wash the fruit we find at the supermarket because of pesticides that are used to deter insects that would eat what we grow. Birds eat these poisoned insects and are poisoned. Excess pesticides wind up in oceanic and riparian (river system) ecosystems, flowing downstream. Pollutants have also been dumped into bodies of water resulting in a poisonous harvest. We as well as the other organisms depend upon these complicated cycles. When they are disturbed things disappear.

According to Marietta College (2006), the first step in biomagnification; the pollutant is at a higher concentration inside the producer than it is in the environment. biomagnification occurs when organisms at the bottom of the food chain concentrate the material above its concentration in the surrounding soil or water. Producers, as we saw earlier, take in inorganic nutrients from their surroundings. Since a lack of these nutrients can limit the growth of the producer, producers will go to great lengths to obtain the nutrients. They will spend considerable energy to pump them into their bodies. They will even take up more than they need immediately and store it, since they can't be "sure" of when the nutrient will be available again (of course, plants don't think about such things, but, as it turns out, those plants, which, for whatever reason, tended to concentrate inorganic nutrients have done better over the years). The problem comes up when a pollutant, such as DDT or mercury, is present in the environment. Chemically, these pollutants resemble essential inorganic nutrients and are brought into the producer's body and stored "by mistake".

The second stage of biomagnification occurs when the producer is eaten. Remember from our discussion of a pyramid of biomass that relatively little energy is available from one tropic level to the next. This means that a consumer (of any level) has to consume a lot of biomass from the lower tropic level. If that biomass contains the pollutant, the pollutant will be taken up in large quantities by the consumer. Pollutants that biomagnified have another characteristic. Not only are they taken up by the producers, but they are absorbed and stored in the bodies of the consumers. This often occurs with pollutants soluble in fat such as DDT or PCB's. These materials are digested from the producer and move into the fat of the consumer. If the consumer is caught and eaten, its fat is digested and the pollutant moves to the fat of the new consumer. In this way, the pollutant builds up in the fatty tissues of the consumers. Water-soluble pollutants usually cannot biomagnified in this way because they would dissolve in the bodily fluids

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of the consumer. Since every organism loses water to the environment, as the water is lost the pollutant would leave as well. Alas, fat simply does not leave the body (Marietta College, 2006).

B. Chemical can be Occurred Biomagnification

In a review of a large number of studies, Suedel et al (1994) concluded that although biomagnification is probably more limited in occurrence than previously thought, there is good evidence that DDT, DDE, PCBs, toxaphene, and the organic forms of mercury and arsenic do biomagnify in nature. For other contaminants, bioconcentration and bioaccumulation account for their high concentrations in organism tissues. More recently, Gray (2002) reached a similar conclusion. However, even this study was criticized by Fisk et al., (2003) for ignoring many relevant studies. Such criticisms are spurring researchers to study carefully all pathways, and Croteau et al. (2005) recently added Cadmium to the

list of biomagnifying metals.

(

http://en.wikipedia.org/wiki/).

There are two main groups of substances that biomagnify. Both are lipophilic and not easily degraded. Novel organic substances are not easily degraded because organisms lack previous exposure and have thus not evolved specific detoxification and excretion mechanisms, as there has been no selection pressure from them. These substances are consequently known as Persistent Organic Pollutants' or POPs. Persistent organic pollutants (POPs) are those chemicals that are not materially broken down over a reasonable period of time, usually measured in decades or more. The POPs of most concern are those that build up in the environment or are bioaccumulated and/or biomagnified in the food chain. The realization and importance of persistent environmental chemicals was first identified in the early 1960s with the publication of Rachel Carson's seminal work, Silent Spring. Carson wrote of the buildup of pesticides in birds and hypothesized that this came from direct and indirect (food chain) exposure. The magnitude of effect from Carson's work can be appreciated when one considers the breadth of environmental health sciences today and the international environmental regulations that have been promulgated.

The chemical characteristics of POPs are relatively similar. Many are polyhalogenated aromatic hydrocarbons (PHAHs), or other polycyclic aromatic hydrocarbons (PAHs) that are very slowly metabolized or otherwise degraded. The chemicals are lipid soluble; hence they are stored in the fatty tissue of all

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animals, and they build up in the food chain. Some classic examples of POPs are the pesticides DDT, Dieldrin, Aldrin, Heptachlor, Mirex, and Kepone. Another group of POPs are the chlorodibenzodioxins, dibenzofurans, and some PCBs. The pesticides were widely used for several years but eventually discontinued for toxicological and ecological reasons. Because of their lipid solubility, the chlorinated compounds are retained and accumulated in the lipids of insects and other invertebrates that are part of the food chain of higher-order predators, and they can eventually end up in the diets of humans and feed animals. Several of these compounds can be sequestered in soil and sediment, such as the PCBs in the Hudson River bottom sediment, where they can exist for decades.

The health effects of these chemicals, as neat compounds, have been very well studied. However, low-dose, lifetime exposure studies are lacking. Many of the organochlorine pesticides cited above are carcinogenic, teratogenic, and neurotoxic. The dioxins and benzofurans are highly toxic and are extremely persistent in the human body as well as the environment. Several of the POPs, including DDT and its metabolites, PCBs, dioxins, and some chlorobenzene, can be detected in human body fat and serum years after any known exposures. Lindane (hexachlorocyclohexane), which was used for the treatment of body lice and as a broad-spectrum insecticide, resulted in very high tissue levels, and in many cases caused acute deaths when used improperly. Lindane and some of its isomers have been identified in market-basket surveys and in human fat samples.

Novel organic substances are DDT, PCBs, and Toxaphene and Inorganic substances are Mercury, Arsenic, and Cadmium. DDT is a colorless contact insecticide, C14H9Cl5, toxic to humans and animals when swallowed or absorbed through the skin. It has been banned in the United States for most uses since 1972.A colorless insecticide that kills on contact. It is poisonous to humans and animals when swallowed or absorbed through the skin. DDT is an abbreviation for dichlorodiphenyltrichloroethane. Although DDT, when it was first invented, was considered a great advance in protecting crops from insect damage and in combating diseases spread by insects, recent discoveries have led to its ban in many countries. Residue from DDT has been shown to remain in the ecosystem and the food chain long after its original use, causing harm and even death to animals considered harmless or useful to man (http://en.wikipedia.org/wiki/Talk:Biomagnification).

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According to Marietta College (2006), not only DDT is toxin to biomagnify, but also all of the following have the potential to biomagnify (Table 1).

Table 1. List of Chemical which has Potential to Biomagnify.

Substance Use and Problems Links

PCB's

polychlorinated biphenyls

• insulators in transformers

• plasticizer

• fire retardant

• biomagnifies

• impairs reproduction

• widespread in aquatic systems

• as airborne contaminants

• in sediments

• in the Mississippi River

PAH's

polynuclear aromatic hydrocarbons

• component of petroleum products • carcinogenic Heavy metals: • mercury • copper • cadmium • chromium • lead • nickel • zinc

• tin (TBT or tributyltin)

• mercury from gold mining

• many from metal processing

• may affect nervous system

• may affect reproduction

• from an interesting student project

• heavy metals in the

Mississippi River - great source!

cyanide

• used in leaching gold

• used in fishing

• toxic

• effects on coral reefs

• health information

• proposed gold mine and its effects

• report of a spill of cyanide

selenium

• concentrated by farming desert soils

• reproductive failures

• toxic

• selenium at a wildlife refuge in Wyoming Source: (http://www.marietta.edu/~biol/102/2bioma95.html)

C. Properties of Biomagnification Chemicals

In order for biomagnification to occur, the pollutant must be: 1) long-lived, 2) mobile, 3) soluble in fats, and 4) biologically active. If a pollutant is short-lived, it will be broken down before it can become dangerous. If it is not mobile, it will stay in one place and is unlikely to be taken up by organisms. If the pollutant is soluble in water it will be excreted by the organism. Pollutants that dissolve in fats, however, may be retained for a long time. It is traditional to measure the amount of pollutants in fatty tissues of organisms such as fish. In mammals, we often test the milk produced by females, since the milk has a lot of fat in it and because the very young are often more susceptible to damage from toxins

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(poisons). If a pollutant is not active biologically, it may biomagnify, but we really don't worry about it much, since it probably won't cause any problems (Marietta College, 2006).

D. Case Examples of Biomagnification

1. Biomagnification was caused by DDT

The best example of biomagnification comes from DDT. DDT stands for dichloro diphenyl trichloroethane. It is a chlorinated hydrocarbon, a class of chemicals which often fit the characteristics necessary for biomagnification. This long-lived pesticide (insecticide) has improved human health in many countries by killing insects such as mosquitoes that spread disease. On the other hand, DDT is effective in part because it does not break down in the environment. It is picked up by organisms in the environment and incorporated into fat. Even here, it does no real damage in many organisms (including humans). In others, however, DDT is deadly or may have more insidious, long-term effects. In birds, for instance, DDT interferes with the deposition of calcium in the shells of the bird's eggs. The eggs laid are very soft and easily broken; birds so afflicted are rarely able to raise young and this causes a decline in their numbers.

This was so apparent in the early 1960's that it led the scientist Rachel Carson to postulate a "silent spring" without the sound of bird calls. Her book "Silent Spring" led to the banning of DDT, the search for pesticides that would not biomagnify, and the birth of the "modern" environmental movement in the 1960's. Birds such as the bald eagle have made comebacks in response to the banning of DDT in the US. Ironically, many of the pesticides which replaced DDT are more dangerous to humans, and, without DDT, disease (primarily in the tropics) claims more human lives.

The above studies refer to aquatic systems. In terrestrial systems, direct uptake by higher trophic levels must be much less, occurring via the lungs. This critique of the biomagnification concept does not mean that we need not be concerned about synthetic organic contaminants and metal elements because they will become diluted. Bioaccumulation and bioconcentration result in these substances remaining in the organisms and not being diluted to non-threatening concentrations. The success of top predatory-bird recovery (bald eagles, peregrine falcons) in North America following the ban on DDT use in agriculture is testamnet to the importance of biomagnification (Marietta College, 2006).

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DDT has a half-life of 15 years, which means if you use 100 kg of DDT, it will break down as follows (Table 2):

Table 2. A half-life of 15 years using 100 kg of DDT Year Amount Remaining

0 100 kg

15 50 kg

30 25 kg

45 12.5 kg

60 6.25 kg

75 3.13 kg

90 1.56 kg

105 0.78 kg

120 0.39 kg

This means that after 100 years, there will still be over a pound of DDT in the environment. If it does bioaccumulate and biomagnify, much of the DDT will be in the bodies of organisms. DDT actually has rather low toxicity to humans (but high toxicity to insects, hence its use as an insecticide). Because it could be safely handled by humans, it was extensively used shortly after its discovery just before WW II. During the war, it was used to reduce mosquito populations and thus control malaria in areas where US troops were fighting (particularly in the tropics). It was also used on civilian populations in Europe, to prevent the spread of lice and the diseases they carried. Refugee populations and those living in destroyed cities would have otherwise faced epidemics of louse-born diseases. After the war, DDT became popular not only to protect humans from insect-borne diseases, but to protect crops as well. As the first of the modern pesticides, it was overused, and soon led to the discovery of the phenomena of insect resistance to pesticides, bioaccumulation, and biomagnification (Marietta College, 2006).

By the 1960's, global problems with DDT and other pesticides were becoming so pervasive that they began to attract much attention. Credit for sounding the warning about DDT and biomagnification usually goes to the scientist Rachel Carson, who wrote the influential book Silent Spring (1962). The silent spring alluded to in the title describes a world in which all the songbirds have been poisoned. Her book of course was attacked by many with vested interests.

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B. Biomagnification was caused by Mercury

Another example of biomagnification comes from mercury. Chan, et al (2003) reporting about impacts of mercury on freshwater fish-eating wildlife and humans. This following is the abstract from their report:

“This paper reviews the current state of knowledge of the toxic effects of mercury on fish-eating birds, mammals, and humans associated with freshwater ecosystems, including new information on the relative risk of elevated methyl Hg exposure for fish-eating birds inhabiting aquatic ecosystems impacted by mining/smelting activities and areas characterized by high geological sources of Hg. The influence of various environmental conditions such as lake pH, DOC, and chemical speciation of Hg, on fish-Hg concentrations and Hg exposure in fish-eating wildlife, are discussed. Although a continuing global effort to decrease the release of this non-essential metal into the environment is warranted, Hg rnethylation and biomagnification may be limited in some environments due to chemical speciation of mercury in soils and sediments (e.g., HgS) and water quality conditions (e.g., high alkalinity and pH) that do not facilitate high methylation rates. We have shown such limitations for a lake where historic Hg mining greatly increased sediment-Hg loadings, yet Hg increases in small fish of various species are currently lower than expected, and top predators (bald eagles), despite having elevated concentrations of Hg in their blood compared with individuals from nearby lakes, exhibit no Hg-related reproductive impairment or other signs of MeHg intoxication. Recent epidemiological studies have shown that fish-eating human populations may be exposed to Hg sufficient to cause significant developmental effects. However, for humans, we conclude that the current USEPA reference dose for MeHg may be too restrictive, particularly for the less sensitive adult. The health status of indigenous peoples relying on the subsistence harvest of wild foods may be negatively affected by such restrictions”.

V. Prevent of Biomagnification

International efforts to minimize exposure to these compounds include the banning of their use except in emergency situations where it has been determined that no other chemical is efficacious. With the exception of DDT, few, if any, of these compounds have been authorized for use. PCBs, which were widely used in capacitors, transformers, and lubricating oils, have not been manufactured for several decades but linger in the environment. Chlorinated dibenzodioxins and dibenzofurans were never products per se, but are byproducts of products made from chlorophenols. The processes by which these final products are manufactured have been altered to minimize the unwanted dioxins. The other source of dioxins is the chlorine bleaching of paper pulp. This bleaching process has been altered to eliminate chlorine, and thereby to eliminate the possibility of dioxins. Several combustion processes also result in the formation of dioxins and benzofurans. Municipal and chemical waste incinerators can be sources of these unwanted by-products. Engineering controls have been put in place in modern facilities to minimize production. However, older and less controlled processes may continue to contaminate the environment

(

http://en.wikipedia.org/wiki/).

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A. Pesticide-Producing Establishments

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) require that production of pesticides and pesticidal devices be conducted in a registered Pesticide-Producing Establishment. ("Production" includes formulation, packaging, repackaging, and relabeling.) Production in an unregistered establishment is a violation of the law. EPA issues Pesticide-Producing Establishment numbers for facilities where pesticides or pesticide devices are produced. These facilities include foreign establishments that import pesticides and/or devices to the United States.

The use and regulation of pesticides has a significant international component. The goals and benefits of International Pesticide Activities (EPA) range from protecting the U.S. food supply to assisting developing countries to develop appropriate pesticide regulatory programs. International agreement; Environmental Protection Agency EPA works closely with U.S. agencies, foreign countries, and international organizations to develop or strengthen international standards and legal mechanisms related to the sound management of chemicals. Quite a few international agreements have been developed on different aspects of pesticides (Environmental Protection Agency, 2006), including:

¾ Stockholm Convention on Persistent Organic Pollutants (POPs)

¾ Convention on Long-Range Transboundary Air Pollutants (LRTAP), Protocol on Persistent Organic Pollutants (POPs)

¾ Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for Certain Hazardous Chemicals and Pesticides in International Trade ¾ Globally Harmonized System (GHS) for Classification and Labelling of

Chemicals

¾ North American Agreement on Environmental Cooperation (NAAEC) ¾ North American Free Trade Agreement (NAFTA), Technical Working

Group on Pesticides

¾ Canada-United States Strategy for the Virtual Elimination of Persistent Toxic Substances in the Great Lakes

¾ International Convention on the Control of Harmful Anti-fouling Systems on Ships

¾

The Vienna Convention for the Protection of the Ozone Layer & the Montreal Protocol on Substances that Deplete the Ozone Layer.

Three federal government agencies share responsibility for the regulation of pesticides. The Environmental Protection Agency (EPA) registers (i.e., approves) the use of pesticides and sets tolerances (the maximum amounts of residues that are permitted in or on a food) if use of a particular pesticide may result in residues in or on food (1). Except for meat, poultry, and certain egg products, for which the Food Safety and Inspection Service (FSIS) of the U.S.

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Department of Agriculture (USDA) is responsible, FDA is charged with enforcing tolerances in imported foods and in domestic foods shipped in interstate commerce. FDA also acquires incidence/level data on particular commodity/pesticide combinations and carries out its market basket survey, the Total Diet Study. Since 1991, USDA's Agricultural Marketing Service (AMS), through contracts with participating states, has carried out a residue testing program directed at raw agricultural products and various processed foods. FSIS and AMS report their pesticide residue data independently.

B. FDA Monitoring Program

Food and Drug Administration (FDA) participates in several international agreements in an effort to minimize incidents of violative residues and to remove trade barriers. A standing request for information from foreign governments on pesticides used on their food exported to the U.S. exists, a provision of the Pesticide Monitoring Improvements Act.

FDA samples individual lots of domestically produced and imported foods and analyzes them for pesticide residues to enforce the tolerances set by EPA. Domestic samples are collected as close as possible to the point of production in the distribution system; import samples are collected at the point of entry into U.S. commerce. Emphasis is on the raw agricultural product, which is analyzed as the unwashed, whole (unpeeled), raw commodity. Processed foods are also included. If illegal residues (above EPA tolerance or no tolerance for a given food/pesticide combination) are found in domestic samples, FDA can invoke various sanctions, such as a seizure or injunction. For imports, shipments may be stopped at the port of entry when illegal residues are found. "Detention without physical examination” (previously called automatic detention) may be invoked for imports based on the finding of one violative shipment if there is reason to believe that the same situation will exist in future lots during the same shipping season for a specific shipper, grower, geographic area, or country (FDA, 2005).

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REFERENCES

Allergy, Sensitivity and Environmental Health Association, Alliance for a Clean Environment, Contaminated Sites Alliance, Greenpeace Australia Pacific, National Toxics Network, Total Environment Centre, and WWF Australia. 2004. A Guide To Implementation of the Stockholm Convention in Australia.

Carson, Rachel. 1962. Silent Spring. Houghton Mifflin.

Chan, H. M; A. M. Scheuhammer; A. Ferran; C. Loupelle. 2003. Impacts of mercury on freshwater fish-eating wildlife and humans. Human and Ecological Risk Assessment; Jun 2003; 9, 4; Academic Research Library pg. 867

Croteau, M., S. N. Luoma, and A. R Stewart. 2005. Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature. Limnol. Oceanogr. 50 (5): 1511-1519.

Ecological & Environmental Learning Services Services (EELSS) (2006). A Food Chain Environmental Problem – Biomagnification.

http://www.eelsinc.org/id62.html

Environmental Protection Agency (EPA). 2006. Pesticides: Regulating Pesticides http://www.epa.gov/oppfead1/international/

EPA (U.S. Environmental Protection Agency). 1997. Mercury Study Report to Congress. Vol. IV: An Assessment of Exposure to Mercury in the United States. EPA-452/R-97-006. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards and Office of Research and Development.

Extension Toxicology Network. (1993). Toxicology Information Briefs

http://extoxnet.orst.edu/tibs/bioaccum.htm

Fisk AT, Hoekstra PF, Borga K,and DCG Muir, 2003. Biomagnification. Mar. Pollut. Bull. 46 (4): 522-524

Food and Drug Administration (FDA). 2005. . Pesticide Program Residue Monitoring 2003. USA. CFSAN/Office of Plant and Dairy Foods May 2005. http://www.fda.gov/

Gray, J.S., 2002. Biomagnification in marine systems: the perspective of an ecologist. Mar. Pollut. Bull. 45: 46?52.

GreenFacts. 2006. ( http://www.greenfacts.org/glossary/abc/biomagnification-biomagnify.htm).

Johnson, BT, and Kennedy, JO (1973) Biomagnification of p,p'-DDT and methoxychlor by bacteria. Applied Microbiology 26, 66-71.

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Landrum, PF and SW Fisher, 1999. Influence of lipids on the bioaccumulation and trophic transfer of organic contaminants in aquatic organisms. Chapter 9 in MT Arts and BC Wainman. Lipids in fresh water ecosystems. Springer Verlag, New York.

LeBlanc, GA 1995. Trophic level differences in the bioconcentration of chemicals: Implication in assessing environmental biomagnification. Env. Sci. Tech. 29:154-160.

Marietta College. 2006. Environmental Biology – Ecosystems.

http://www.marietta.edu/~biol/102/ecosystem.html#Biologicalmagnificatio n6

Miller, R.W. 2006. On my mind: The Ecological Explanation for the Environmental Crisis. Electronic Green Journal, San Francisco, USA, http://egj.lib.uidaho.edu/egj23/miller5.html

Odum, E.P. 1971. Fundamental of Ecology. Third Edition. W.B. Saunders company. Philadelphia.

Rasmussen, J.B., Rowan, D.J., Lean, D.R.S. and Carey, J.H., 1990. Food chain structure in Ontario lakes determines PCB levels in lake trout (Salvelinus namaycush) and other pelagic fish. Can. J. Fish. Aquat. Sci. 47, pp. 2030?2038

Steingraber, Sandra. 1998. Living Downstream. Vintage Books.

Suedel, B.C., Boraczek, J.A., Peddicord, R.K., Clifford, P.A. and Dillon, T.M., 1994. Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems. Reviews of Environmental Contamination and Toxicology 136: 21?89.

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DDT has a half-life of 15 years, which means if you use 100 kg of DDT, it will break down as follows (Table 2):

Table 2. A half-life of 15 years using 100 kg of DDT

Year Amount Remaining

0 100 kg

15 50 kg

30 25 kg

45 12.5 kg

60 6.25 kg

75 3.13 kg

90 1.56 kg

105 0.78 kg

120 0.39 kg

By the 1960's, global problems with DDT and other pesticides were becoming so pervasive that they began to attract much attention. Credit for sounding the warning about DDT and biomagnification usually goes to the scientist Rachel Carson, who wrote the influential book Silent Spring (1962). The silent spring alluded to in the title describes a world in which all the songbirds

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B. Biomagnification was caused by Mercury

V. Prevent of Biomagnification

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A. Pesticide-Producing Establishments

¾ Stockholm Convention on Persistent Organic Pollutants (POPs)

¾ Convention on Long-Range Transboundary Air Pollutants (LRTAP), Protocol on Persistent Organic Pollutants (POPs)

Chemicals

¾ North American Agreement on Environmental Cooperation (NAAEC) ¾ North American Free Trade Agreement (NAFTA), Technical Working

Group on Pesticides

¾ Canada-United States Strategy for the Virtual Elimination of Persistent Toxic Substances in the Great Lakes

¾ International Convention on the Control of Harmful Anti-fouling Systems on Ships

¾

The Vienna Convention for the Protection of the Ozone Layer & the Montreal Protocol on Substances that Deplete the Ozone Layer.

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B. FDA Monitoring Program

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REFERENCES

Carson, Rachel. 1962. Silent Spring. Houghton Mifflin.

Chan, H. M; A. M. Scheuhammer; A. Ferran; C. Loupelle. 2003. Impacts of mercury on freshwater fish-eating wildlife and humans. Human and Ecological Risk Assessment; Jun 2003; 9, 4; Academic Research Library pg. 867

Croteau, M., S. N. Luoma, and A. R Stewart. 2005. Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature. Limnol. Oceanogr. 50 (5): 1511-1519.

Ecological & Environmental Learning Services Services (EELSS) (2006). A Food Chain Environmental Problem – Biomagnification. http://www.eelsinc.org/id62.html

Environmental Protection Agency (EPA). 2006. Pesticides: Regulating Pesticides http://www.epa.gov/oppfead1/international/

Extension Toxicology Network. (1993). Toxicology Information Briefs http://extoxnet.orst.edu/tibs/bioaccum.htm

Fisk AT, Hoekstra PF, Borga K,and DCG Muir, 2003. Biomagnification. Mar. Pollut. Bull. 46 (4): 522-524

Food and Drug Administration (FDA). 2005. . Pesticide Program Residue Monitoring 2003. USA. CFSAN/Office of Plant and Dairy Foods May 2005. http://www.fda.gov/

Gray, J.S., 2002. Biomagnification in marine systems: the perspective of an ecologist. Mar. Pollut. Bull. 45: 46?52.

GreenFacts. 2006. (http://www.greenfacts.org/glossary/abc/biomagnification-biomagnify.htm).

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LeBlanc, GA 1995. Trophic level differences in the bioconcentration of chemicals: Implication in assessing environmental biomagnification. Env. Sci. Tech. 29:154-160.

Marietta College. 2006. Environmental Biology – Ecosystems. http://www.marietta.edu/~biol/102/ecosystem.html#Biologicalmagnificatio n6

Miller, R.W. 2006. On my mind: The Ecological Explanation for the Environmental Crisis. Electronic Green Journal, San Francisco, USA, http://egj.lib.uidaho.edu/egj23/miller5.html

Odum, E.P. 1971. Fundamental of Ecology. Third Edition. W.B. Saunders company. Philadelphia.

Rasmussen, J.B., Rowan, D.J., Lean, D.R.S. and Carey, J.H., 1990. Food chain structure in Ontario lakes determines PCB levels in lake trout (Salvelinus namaycush) and other pelagic fish. Can. J. Fish. Aquat. Sci. 47, pp. 2030?2038

Steingraber, Sandra. 1998. Living Downstream. Vintage Books.

Biomagnification

KARYA TULIS