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110-443: Environmental toxicology is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms . Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels. Rachel Carson is considered the mother of environmental toxicology, as she made it

220-432: A trophic cascade can occur. PCBs can cause harm to human health or even death when eaten. PCBs can be transported by birds from aquatic sources onto land via feces and carcasses. PCBs undergo xenobiotic biotransformation, a mechanism used to make lipophilic toxins more polar and more easily excreted from the body. The biotransformation is dependent on the number of chlorine atoms present, along with their position on

330-455: A bridge for plastic pollution to be transported from terrestrial environments into marine environments. It has been estimated that 88–95% of marine plastic is exported into the ocean by just 10 major rivers. An organism can accumulate PCBs by consuming other organisms that have previously ingested PCBs from terrestrial, freshwater, or marine environments. The concentration of PCBs within an organism will increase over their lifetime; this process

440-499: A coolant in electric transformers, PCBs still persist in built environments. Some PCBs share a structural similarity and toxic mode of action with dioxins . Other toxic effects such as endocrine disruption (notably blocking of thyroid system functioning) and neurotoxicity are known. The bromine analogues of PCBs are polybrominated biphenyls (PBBs), which have analogous applications and environmental concerns. An estimated 1.2 million tons have been produced globally. Though

550-437: A decrease in the number of academic disciplines. One key question is how well the challenge can be decomposed into subparts, and then addressed via the distributed knowledge in the community. The lack of shared vocabulary between people and communication overhead can sometimes be an issue in these communities and projects. If challenges of a particular type need to be repeatedly addressed so that each one can be properly decomposed,

660-451: A distinct field within toxicology in 1962 with the publication of her book Silent Spring , which covered the effects of uncontrolled pesticide use. Carson's book was based extensively on a series of reports by Lucille Farrier Stickel on the ecological effects of the pesticide DDT . Organisms can be exposed to various kinds of toxicants at any life cycle stage, some of which are more sensitive than others. Toxicity can also vary with

770-425: A food web. Pesticides can be categorized according to the pests they target. Insecticides are used to eliminate agricultural pests that attack various fruits and crops. Herbicides target herbal pests such as weeds and other unwanted plants that reduce crop production. Pesticides in general have been shown to negatively impact the reproductive and endocrine systems of various reptiles and amphibians, so much that it

880-463: A huge part of environmental pollutions and their toxicity "is a problem of increasing significance for ecological, evolutionary, nutritional and environmental reasons." Aluminum Aluminum is the most common natural metal in the Earth's crust and is naturally cycled throughout the environment via processes like the weathering of rocks and volcano eruptions. Those natural processes release more aluminum into

990-415: A multidisciplinary community can be exceptionally efficient and effective. There are many examples of a particular idea appearing in different academic disciplines, all of which came about around the same time. One example of this scenario is the shift from the approach of focusing on sensory awareness of the whole, "an attention to the 'total field ' ", a "sense of the whole pattern, of form and function as

1100-593: A national operating that "permits program to make the law more workable, and strengthened enforcement to help ensure better compliance with the Act." As mentioned above, though the United States did ban the use of polychlorinated biphenyls (PCBs), there is the possibility that they are present in products made before the PCB ban in 1979. The Environmental Protection Agency (EPA) released its ban on PCBs on April 19, 1979. According to

1210-409: A protoplastic poison since it affects primarily the sulphydryl group of cells causing malfunctioning of cell respiration, cell enzymes and mitosis." Another extremely toxic metal, lead can and has been known to cause "extensive environmental contamination and health problems in many parts of the world." The physical appearance of lead is bright and silver colored metal. Some sources of lead pollution in

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1320-418: A qualitative assessment and therefore manipulated. The number of citations is dependent on the number of persons working in the same domain instead of inherent quality or published result's originality. Polychlorinated biphenyls Because of their longevity, PCBs are still widely in use, even though their manufacture has declined drastically since the 1960s, when a host of problems were identified. With

1430-516: A scale, around a norm, hierarchize individuals in relation to one another and, if necessary, disqualify and invalidate." (Foucault, 1975/1979, p. 223) Communities of academic disciplines can be found outside academia within corporations, government agencies, and independent organizations, where they take the form of associations of professionals with common interests and specific knowledge. Such communities include corporate think tanks , NASA , and IUPAC . Communities such as these exist to benefit

1540-538: A semi-closed application. In contrast, the major open application of PCBs was in carbonless copy ("NCR") paper , which even presently results in paper contamination. Other open applications were lubricating and cutting oils, and as plasticizers in paints and cements, stabilizing additives in flexible PVC coatings of electrical cables and electronic components, pesticide extenders, reactive flame retardants and sealants for caulking , adhesives , wood floor finishes, such as Fabulon and other products of Halowax in

1650-410: A significant quantity of PCBs. As the pressure of ocean water increases with depth, PCBs become heavier than water and sink to the deepest ocean trenches where they are concentrated. A small volume of PCBs has been detected throughout the Earth's atmosphere. The atmosphere serves as the primary route for global transport of PCBs, particularly for those congeners with one to four chlorine atoms. In

1760-661: A specific academic discipline, are classified as generalists . While academic disciplines in and of themselves are more or less focused practices, scholarly approaches such as multidisciplinarity/interdisciplinarity , transdisciplinarity , and cross-disciplinarity integrate aspects from multiple academic disciplines, therefore addressing any problems that may arise from narrow concentration within specialized fields of study. For example, professionals may encounter trouble communicating across academic disciplines because of differences in language, specified concepts, or methodology. Some researchers believe that academic disciplines may, in

1870-418: A transdisciplinary team is more holistic and seeks to relate all disciplines into a coherent whole. Cross-disciplinary knowledge is that which explains aspects of one discipline in terms of another. Common examples of cross-disciplinary approaches are studies of the physics of music or the politics of literature . Bibliometrics can be used to map several issues in relation to disciplines, for example,

1980-417: A treatment of unwanted PCBs generally requires high heat or catalysis (see Methods of destruction below). PCBs readily penetrate skin , PVC (polyvinyl chloride), and latex (natural rubber). PCB-resistant materials include Viton , polyethylene , polyvinyl acetate (PVA), polytetrafluoroethylene (PTFE), butyl rubber , nitrile rubber , and Neoprene . PCBs are derived from biphenyl , which has

2090-445: A unity", an "integral idea of structure and configuration". This has happened in art (in the form of cubism), physics, poetry, communication and educational theory. According to Marshall McLuhan , this paradigm shift was due to the passage from the era of mechanization, which brought sequentiality, to the era of the instant speed of electricity, which brought simultaneity. Multidisciplinary approaches also encourage people to help shape

2200-483: Is a subdivision of knowledge that is taught and researched at the college or university level. Disciplines are defined (in part) and recognized by the academic journals in which research is published, and the learned societies and academic departments or faculties within colleges and universities to which their practitioners belong. Academic disciplines are conventionally divided into the humanities (including philosophy , language , art and cultural studies ),

2310-409: Is also important to monitor fishes not just for public health, but also to assess the health of coastal ecosystems. For instance, it has been shown that fish (i.e. rainbow trout ) exposed to higher cadmium levels and grow at a slower rate than fish exposed to lower levels or none. Moreover, cadmium can potentially alter the productivity and mating behaviours of these fish. Heavy metals can also alter

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2420-402: Is called bioaccumulation. PCB concentrations within an organism also change depending upon which trophic level they occupy. When an organism occupies a high trophic level, like orcas or humans , they will accumulate more PCBs than an organism that occupies a low trophic level, like phytoplankton . If enough organisms with a trophic level are killed due to the accumulation of toxins, like PCB,

2530-607: Is cautiously thought to be one of the main factors behind the decline in their populations all over the world. These pesticides impair their immune, nervous, behavioral systems including causing lower fertility rates, abnormal hormone levels, and lower fitness of offspring. Amphibians are thought to be especially in low decline because the release of agricultural pesticides is simultaneous with the secretion of pheromones during their season of reproduction. For instance, it has been demonstrated that greater quantities of pesticides correlates with greater number of defects in toads. For example,

2640-639: Is evidence that shows that C. riparius exhibits genetically based heavy metal tolerance. Additionally, a case study in China looked at the concentrations of Cu (copper), Cr (chromium), Cd (cadmium), and Pb (lead) in the edible parts of the fishes Pelteobagrus fluvidraco, the banded catfish, and Cyprinus carpio, the common carp living in Taihu Lake. These metals were actively being released from sources such as industrial waste stemming from agriculture and mining and then going into coastal ecosystems and becoming stored in

2750-543: Is linked to cancer not only in fish, but also in mammals like humans. Additionally, atrazine is known to induce aromatase which causes the bodies of fish and amphibians to produce estrogen even when they are not supposed to. The herbicide also causes changes in gene expression which can be passed down from parent to offspring and get in the way of thyroid homeostasis. For example, a study done on male African clawed frogs show that exposure to atrazine led to smaller testicular size and lower testosterone levels. Another study done with

2860-427: Is made up of people from different academic disciplines and professions. These people are engaged in working together as equal stakeholders in addressing a common challenge. A multidisciplinary person is one with degrees from two or more academic disciplines. This one person can take the place of two or more people in a multidisciplinary community. Over time, multidisciplinary work does not typically lead to an increase or

2970-459: Is not consistent and because PCBs have certain properties ( chemical stability, non-flammability) they have been used in a colossal amount of commercial and industrial practices. Some of those include, "Electrical, heat transfer and hydraulic equipment, plasticizers in paints, plastics and rubber products and pigments, dyes and carbonless copy paper" to name a few. Metals like cadmium, mercury, and lead have minimal roles in living organisms if any, so

3080-626: Is performing more functions in the warmer months, it naturally has a faster metabolism and has less PCB accumulation. However, multiple cold-water periods mixed with toxic PCBs with coplanar chlorine molecules can be detrimental to perch health. Enantiomers of chiral compounds have similar chemical and physical properties, but can be metabolized by the body differently. This was looked at in bowhead whales ( Balaena mysticetus ) for two main reasons: they are large animals with slow metabolisms (meaning PCBs will accumulate in fatty tissue) and few studies have measured chiral PCBs in cetaceans. They found that

3190-420: Is suspected of having certain effects on liver and skin of humans. They are also suspected of causing cancer as well. EPA "estimates that 150 million pounds of PCBs are dispersed throughout the environment, including air and water supplies; an additional 290 million pounds are located in landfills in this country." Again, even though they have been banned, there is still a large amount of PCBs are circulating within

3300-530: Is the primary source of PCB contamination in the atmosphere. In the biosphere , PCBs can be degraded by the sun , bacteria or eukaryotes , but the speed of the reaction depends on both the number and the disposition of chlorine atoms in the molecule: less substituted, meta - or para -substituted PCBs undergo biodegradation faster than more substituted congeners. In bacteria, PCBs may be dechlorinated through reductive dechlorination , or oxidized by dioxygenase enzyme. In eukaryotes, PCBs may be oxidized by

3410-431: Is thought to be linked to PCB 77 metabolism, something that was not measured in this study. Temperature plays a key role in the ecology, physiology and metabolism of aquatic species. The rate of PCB metabolism was temperature dependent in yellow perch ( Perca flavescens ). In fall and winter, only 11 out of 72 introduced PCB congeners were excreted and had halflives of more than 1,000 days. During spring and summer when

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3520-645: Is unlikely) will be allowed to continue for the life of the equipment." In terms of electrical equipment containing PCBs is allowed under specific controlled conditions. Out of the 750 million pounds of PCBs, electrical equipment represents 578 million pounds. Any new manufacture of PCB is prohibited. There are many sources of environmental toxicity that can lead to the presence of toxicants in our food, water and air. These sources include organic and inorganic pollutants, pesticides and biological agents, all of which can have harmful effects on living organisms. There can be so called point sources of pollution, for instance

3630-481: The Baltic Sea have been shown to have significantly higher PCB levels than farmed salmon as the wild fish live in a heavily contaminated environment. PCBs pertains to a group of human-produced "organic chemicals known as Chlorinated hydrocarbons" The chemical and physical properties of a PCS determine the quantity and location chlorine and unlike other chemicals, they have no form of identification. The range of toxicity

3740-845: The Chernobyl disaster in 1986, the nuclear radiation damaged the surrounding plants' reproductive tissues , and it took approximately three years for these plans to regain their reproductive abilities. The study of radiation and its effects on the environment is known as radioecology . The most known or common types of heavy metals include zinc, arsenic, copper, lead, nickel, chromium, aluminum, and cadmium. All of these types cause certain risks on human and environment health. Though certain amount of these metals can actually have an important role in, for example, maintaining certain biochemical and physiological, "functions in living organisms when in very low concentrations, however they become noxious when they exceed certain threshold concentrations." Heavy metal are

3850-422: The cytochrome P450 enzyme. Like many lipophilic toxins, PCBs undergo biomagnification and bioaccumulation primarily due to the fact that they are easily retained within organisms. Plastic pollution, specifically microplastics , are a major contributor of PCBs into the biosphere and especially into marine environments. PCBs concentrate in marine environments because freshwater systems, like rivers, act as

3960-408: The scientific disciplines (such as physics , chemistry , and biology ), the formal sciences like mathematics and computer science ; the social sciences are sometimes considered a fourth category. Individuals associated with academic disciplines are commonly referred to as experts or specialists . Others, who may have studied liberal arts or systems theory rather than concentrating in

4070-496: The "biological processes in various plants such as maize, wheat, barley, cauliflower, citrullus and in vegetables. Chromium toxicity causes chlorosis and necrosis in plants." Pesticides are a major source of environmental toxicity. These chemically synthesized agents have been known to persist in the environment long after their administration. The poor biodegradability of pesticides can result in bioaccumulation of chemicals in various organisms along with biomagnification within

4180-456: The EPA, "Although PCBs are no longer being produced in this country, we will now bring under control the vast majority of PCBs still in use," said EPA Administrator Douglas M. Castle. "This will help prevent further contamination of our air, water and food supplies from a toxic and very persistent man-made chemical." PCBs has been tested on laboratory animals and have caused cancer and birth defects. PCB

4290-454: The Northern leopard frog and Blanchard's cricket frog found that atrazine lowered their success with metamorphosis, the process of turning into an adult frog from the initial stage of a tadpole. This makes sense since metamorphosis is controlled by hormones from the thyroid gland which atrazine is known to negatively impact. Multidisciplinarity An academic discipline or academic field

4400-464: The PCB metabolism in the liver of four sea turtle species (green, olive ridley , loggerhead and hawksbill), green and hawksbill sea turtles have noticeably higher hydroxylation rates of PCB 52 than olive ridley or loggerhead sea turtles. This is because the green and hawksbill sea turtles have higher P450 2-like protein expression. This protein adds three hydroxyl groups to PCB 52, making it more polar and water-soluble. P450 3-like protein expression that

4510-448: The U.S., de-dusting agents, waterproofing compounds, casting agents. It was also used as a plasticizer in paints and especially "coal tars" that were used widely to coat water tanks, bridges and other infrastructure pieces. Modern sources include pigments , which may be used in inks for paper or plastic products. PCBs are also still found in old equipment like capacitors, ballasts, X-ray machine, and other e-waste. PCBs have entered

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4620-975: The US EPA enforced the federal ban as of 1978, PCBs continued to create health problems in later years through their continued presence in soil and sediment, and from products which were made before 1979. In 1988, Japanese scientists Tanabe et al. estimated 370,000 tons were in the environment globally, and 780,000 tons were present in products, landfills, and dumps or kept in storage. The compounds are pale-yellow viscous liquids . They are hydrophobic, with low water solubilities : 0.0027–0.42  ng /L for Aroclors brand , but they have high solubilities in most organic solvents , oils, and fats . They have low vapor pressures at room temperature. They have dielectric constants of 2.5–2.7, very high thermal conductivity , and high flash points (from 170 to 380 °C). The density varies from 1.182 to 1.566 g/cm . Other physical and chemical properties vary widely across

4730-447: The US, Aroclor 1260 and Aroclor 1254 were the main mixtures used before 1950; Aroclor 1242 was the main mixture used in the 1950s and 1960s until it was phased out in 1971 and replaced by Aroclor 1016. One estimate (2006) suggested that 1 million tonnes of PCBs had been produced. 40% of this material was thought to remain in use. Another estimate put the total global production of PCBs on

4840-411: The accumulation of these, even if a little, can lead to health issues. For example, because humans consume fish, it is important to monitor fishes for such trace metals. It has been known for a long time that these trace metals get passed up the food web because of their lack of biodegradability or capability to break down. Such build-up can lead to liver damage and cardiovascular diseases in people. It

4950-692: The amount of metals in the gills represents the amount that has been accumulated from the surrounding water. This is why the gills are thought to be better bioindicators of metal pollution. Radiation is given off by matter as either rays or waves of pure energy or high-speed particles. Rays or waves of energy , also known as electromagnetic radiation, include sunlight, X-rays , radar , and radio waves . Particle radiation includes alpha and beta particles and neutrons . When humans and animals are exposed to high radiation levels, they can develop cancer , congenital disabilities , or skin burns. Plants also face problems when exposed to large levels of radiation. After

5060-418: The arts and social sciences. Communities of academic disciplines would contribute at varying levels of importance during different stages of development. These categories explain how the different academic disciplines interact with one another. Multidisciplinary (or pluridisciplinary) knowledge is associated with more than one existing academic discipline or profession. A multidisciplinary community or project

5170-510: The atmosphere, PCBs may be degraded by hydroxyl radicals , or directly by photolysis of carbon–chlorine bonds (even if this is a less important process). Atmospheric concentrations of PCBs tend to be lowest in rural areas, where they are typically in the picogram per cubic meter range, higher in suburban and urban areas, and highest in city centres, where they can reach 1  ng /m or more. In Milwaukee , an atmospheric concentration of 1.9 ng/m has been measured, and this source alone

5280-517: The average PCB concentrations in the blubber were approximately four times higher than the liver; however, this result is most likely age- and sex-dependent. As reproductively active females transferred PCBs and other poisonous substances to the fetus, the PCB concentrations in the blubber were significantly lower than males of the same body length (less than 13 meters). The toxicity of PCBs varies considerably among congeners . The coplanar PCBs, known as nonortho PCBs because they are not substituted at

5390-399: The average daily water temperature was above 20 °C, persistent PCBs had halflives of 67 days. The main excretion processes were fecal egestion, growth dilution and loss across respiratory surfaces. The excretion rate of PCBs matched with the perch's natural bioenergetics , where most of their consumption, respiration and growth rates occur during the late spring and summer. Since the perch

5500-552: The benefit of all societies' growth and wellbeing. Regional examples such as Biopeople and industry-academia initiatives in translational medicine such as SHARE.ku.dk in Denmark provide evidence of the successful endeavour of multidisciplinary innovation and facilitation of the paradigm shift. In practice, transdisciplinary can be thought of as the union of all interdisciplinary efforts. While interdisciplinary teams may be creating new knowledge that lies between several existing disciplines,

5610-416: The chloroacetanilide class of herbicides is used worldwide in the control of weeds and grasses for agriculture. They are mainly used for crops such as corn, rice, soybean, sunflower, cotton, among others and are able to stay in the environment for long periods of time. Thus they can be found in soil, groundwater, and surface water due to soil erosion, leaching, and surface runoff. The amount of time they stay in

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5720-452: The class. As the degree of chlorination increases, melting point and lipophilicity increase, and vapour pressure and water solubility decrease. PCBs do not easily break down or degrade, which made them attractive for industries. PCB mixtures are resistant to acids, bases, oxidation, hydrolysis, and temperature change. They can generate extremely toxic dibenzodioxins and dibenzofurans through partial oxidation. Intentional degradation as

5830-694: The current physical sciences. Prior to the twentieth century, few opportunities existed for science as an occupation outside the educational system. Higher education provided the institutional structure for scientific investigation, as well as economic support for research and teaching. Soon, the volume of scientific information rapidly increased and researchers realized the importance of concentrating on smaller, narrower fields of scientific activity. Because of this narrowing, scientific specializations emerged. As these specializations developed, modern scientific disciplines in universities also improved their sophistication. Eventually, academia's identified disciplines became

5940-463: The discovery of PCBs' environmental toxicity , and classification as persistent organic pollutants , their production was banned for most uses by United States federal law on January 1, 1978. The International Agency for Research on Cancer (IARC) rendered PCBs as definite carcinogens in humans. According to the U.S. Environmental Protection Agency (EPA), PCBs cause cancer in animals and are probable human carcinogens. Moreover, because of their use as

6050-524: The drains from a specific factory, but also non-point sources (diffuse sources) like the rubber from car tires that contain numerous chemicals and heavy metals that are spread in the environment. PCBs are organic pollutants that are still present in our environment today, despite being banned in many countries, including the United States and Canada. Due to the persistent nature of PCBs in aquatic ecosystems , many aquatic species contain high levels of this chemical. For example, wild salmon ( Salmo salar ) in

6160-433: The early twentieth century, new academic disciplines such as education and psychology were added. In the 1970s and 1980s, there was an explosion of new academic disciplines focusing on specific themes, such as media studies , women's studies , and Africana studies . Many academic disciplines designed as preparation for careers and professions, such as nursing , hospitality management , and corrections , also emerged in

6270-414: The easternmost regions of Slovakia. Although deliberate production of PCBs is banned by international treaty, significant amounts of PCBs are still being "inadvertently" produced. Research suggests that 45,000 tons of 'by-product' PCBs are legally produced per year in the US as part of certain chemical and product formulations. Commercial production of PCBs was banned in the United States in 1979, with

6380-452: The ecosystem by reducing its productivity and stability. Although legislation implemented since the early 1970s had intended to minimize harmful effects of environmental toxicants upon all species, McCarty (2013) has warned that "longstanding limitations in the implementation of the simple conceptual model that is the basis of current aquatic toxicity testing protocols" may lead to an impending environmental toxicology "dark age". To protect

6490-593: The effects on the water environment. The biggest sources of mercury pollution include "agriculture, municipal wastewater discharges, mining, incineration, and discharges of industrial wastewater" all relatively connected to water. Mercury exists in three different forms and all three possess different levels of bioavailability and toxicity. The three forms include organic compounds, metallic elements and inorganic salts. As stated above, they are present in water resources such as oceans, rivers and lakes. Studies have shown that mercury turns into methylmercury (MeHg) and seeps into

6600-412: The environment and are possibly causing effects on the skin and liver of humans. There were some cases in which people or companies that disposed of PCBs incorrectly. Up until now, there have been four cases in which EPA had to take legal actions against people/companies for their methods of disposal. The two cases involving the companies, were fined $ 28,600 for improper disposal. It is unknown what fined

6710-457: The environment depends on the soil type and climate conditions like temperature and moisture. Chloroacetanilide herbicides include acetochlor, alachlor, among others. They are all listed as B2, L2, and C classes of carcinogens by the U.S. EPA. Another herbicide called atrazine is still commonly used throughout the world even with the European Union banning its usage in 2005. Shockingly, its use

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6820-456: The environment include Metal plating and fishing operations, soil waste, factory chimneys, smelting of ores, wastes from batter industries, fertilizers and pesticides and many more. Unlike, other metals such as copper, lead only plays a physiological aspect and no biological functions. In the US, "more than 100 to 200,000 tons of lead per year is being released from vehicle exhausts" and some can be brought in by plants, flow in water or fixation into

6930-425: The environment through both use and disposal. The environmental fate of PCBs is complex and global in scale. Because of their low vapour pressure , PCBs accumulate primarily in the hydrosphere , despite their hydrophobicity , in the organic fraction of soil , and in organisms including the human body. The hydrosphere is the main reservoir. The immense volume of water in the oceans is still capable of dissolving

7040-541: The environment, the National Environmental Policy Act (NEPA) was written. The main point that NEPA brings to light is that it "assures that all branches of government give proper consideration to the environment prior to undertaking any major federal actions that significantly affect the environment." This law was passed in 1970 and also founded the Council on Environmental Quality (CEQ). The importance of CEQ

7150-538: The environment. In humans, arsenic can cause cancer in the bladder, skin, lungs and liver. One of the major sources of arsenic exposure in humans is contaminated water, which is a problem in more than 30 countries in the world. Humans tend to encounter arsenic by "natural means, industrial source, or from unintended sources." Water can become contaminated by arsenical pesticides or natural arsenical chemicals. There are some cases in which arsenic has been used in suicide attempts and can result in acute poisoning. Arsenic "is

7260-627: The environment. Plankton then get the metal into their system, and they are then eaten by other marine organisms. This cycle continues up the food web. This process is called biomagnification and "causes significant disturbance to aquatic lives." Mercury hurts marine life but can also be very hurtful towards humans' nervous system. Higher levels of mercury exposure can change many brain functions. It can "lead to shyness, tremors, memory problems, irritability, and changes in vision or hearing." Furthermore, breathing in mercury can lead to dysfunction in sensory and mental capabilities in humans as well such as with

7370-446: The flow of ideas within and among disciplines (Lindholm-Romantschuk, 1998) or the existence of specific national traditions within disciplines. Scholarly impact and influence of one discipline on another may be understood by analyzing the flow of citations. The Bibliometrics approach is described as straightforward because it is based on simple counting. The method is also objective but the quantitative method may not be compatible with

7480-463: The following names: Brazil Czech Republic and Slovakia France Germany Italy Japan Former USSR United Kingdom United States The only North American producer, Monsanto Company , marketed PCBs under the trade name Aroclor from 1930 to 1977. These were sold under trade names followed by a four-digit number. In general, the first two digits refer to the product series as designated by Monsanto (e.g. 1200 or 1100 series);

7590-445: The following to be done: "1. Pre-manufacture testing of chemicals to determine health or environmental risk 2. Review of chemicals for significant risk prior to the start of commercial production 3. Restriction or prohibition on the production or disposal of certain chemicals 4. Import and export control of chemicals prior to their entering or leaving the USA." The Clean Air Act was aided by

7700-475: The formula C 12 H 10 , sometimes written (C 6 H 5 ) 2 . In PCBs, some of the hydrogen atoms in biphenyl are replaced by chlorine atoms. There are 209 different chemical compounds in which one to ten chlorine atoms can replace hydrogen atoms. PCBs are typically used as mixtures of compounds and are given the single identifying CAS number 1336-36-3 . About 130 different individual PCBs are found in commercial PCB products. Toxic effects vary depending on

7810-563: The foundations for scholars of specific specialized interests and expertise. An influential critique of the concept of academic disciplines came from Michel Foucault in his 1975 book, Discipline and Punish . Foucault asserts that academic disciplines originate from the same social movements and mechanisms of control that established the modern prison and penal system in eighteenth-century France , and that this fact reveals essential aspects they continue to have in common: "The disciplines characterize, classify, specialize; they distribute along

7920-429: The freshwater environments than do humans, but anthropogenic impact has been causing values to rise above the recommended amount by the U.S. EPA and World Health Organization. Aluminum is used commonly in industrially-made items like paints, paper, household appliances, packaging, processing of food and water, and for health care items like antiperspirants and vaccine production. Run-off from those industrial uses then bring

8030-549: The future, be replaced by what is known as Mode 2 or "post-academic science", which involves the acquisition of cross-disciplinary knowledge through the collaboration of specialists from various academic disciplines. It is also known as a field of study , field of inquiry , research field and branch of knowledge . The different terms are used in different countries and fields. The University of Paris in 1231 consisted of four faculties : Theology , Medicine , Canon Law and Arts . Educational institutions originally used

8140-458: The genetic makeup in aquatic organisms. In Canada, a study examined genetic diversity in wild yellow perch along various heavy metal concentration gradients in lakes polluted by mining operations. Researchers wanted to determine what effect metal contamination had on evolutionary responses among populations of yellow perch. Along the gradient, genetic diversity over all loci was negatively correlated with liver cadmium contamination. Additionally, there

8250-403: The gold shops downtown, further emphasizing the cost of gold-mining in such native communities and the need for better programs directed towards preventing its spread. According to, ATSDR ranking, cadmium is the 7th most toxic heavy metal. Cadmium is interesting in that once it is exposed to humans (at work) or animals in their environment, it will accumulate inside the body throughout the life of

8360-575: The human/animal. Though cadmium was used as replacement for tin in WWI and pigment in paint industries back in the day, currently it is seen mostly in rechargeable batteries, tobacco smoke and some alloys production. As stated by the Agency for Toxic Substance and Disease Registry, in " the US, more than 500,000 workers get exposed to toxic cadmium each year." It is also stated that the highest exposure to cadmium can be seen in China and Japan. The effects of cadmium on

8470-583: The innovation of the future. The political dimensions of forming new multidisciplinary partnerships to solve the so-called societal Grand Challenges were presented in the Innovation Union and in the European Framework Programme, the Horizon 2020 operational overlay. Innovation across academic disciplines is considered the pivotal foresight of the creation of new products, systems, and processes for

8580-643: The interpretation within Courts. Not only did Courts interpret NEPA to expand over direct environmental impacts from any projects, specifically federal, but also indirect actions from federal projects. TSCA, also known as the Toxic Substance Control Act, is a federal law that regulates industrial chemicals that have the potential to be harmful to humans and the environment. TSCA specifically targets "the manufacture, importation, storage, use, disposal, and degradation of chemicals in commercial use." The EPA allows

8690-576: The kidney and bones is huge. It can cause bone mineralization which "is the process of laying down minerals on a matrix of the bone". This can happen through renal dysfunction or bone damage. The 7th most abundant element, chromium, can occur naturally when one burns oil and coal and is released into the environment through sewage and fertilizers. Chromium usage can be seen in, "industries such as metallurgy, electroplating, production of paints and pigments, tanning, wood preservation , chemical production and pulp and paper production ." Chromium toxicity affects

8800-460: The local fish, especially their organs. This was especially alarming because too much copper consumption can lead to diarrhea and nausea in humans and liver damage in fish. Additionally, too much lead can lead to defects in learning, behavior, metabolism, and growth in some vertebrates, including humans. Much of these heavy metals were found in the two fish species' liver, kidney, and gills, however, their concentrations were fortunately found to be below

8910-501: The metal flowing into the environment. Generally, too much exposure to aluminum affects motor and cognitive skills. In mammals, the metal has been shown to affect gene expression, DNA repair, and DNA binding. One study showed how the effects of aluminum include neurodegeneration and nerve cell death in mice. Another study has shown it to be related to human diseases associated with the nervous system such as Alzheimer's and Parkinson's disease and autism. Exposure to contaminants can change

9020-444: The most in carnivorous species with omnivorous species following behind. In this case, perhaps due to the properties of the water differing at different parts of the year, there were more heavy metals spotted in the two fish species in the summer compared to the winter. Overall, it is relatively understood that the amount of metals in the liver and kidney of a fish represents the amount that has been actively stored in their bodies whereas

9130-450: The most likely to leave the organism. However, some metabolites of PCBs containing ortho – meta protons have increased steric hindrance from the oxygen, causing increased stability and an increased chance of accumulation. Metabolism is also dependent on the species of organism; different organisms have slightly different P450 enzymes that metabolize certain PCBs better than others. Looking at

9240-411: The naming system is Aroclor 1016 which was produced by distilling 1242 to remove the highly chlorinated congeners to make a more biodegradable product. "1016" was given to this product during Monsanto's research stage for tracking purposes but the name stuck after it was commercialized. Different Aroclors were used at different times and for different applications. In electrical equipment manufacturing in

9350-523: The neurotransmitters in their bodies such as adrenaline and dopamine. Arsenic, one of the most important heavy metals, causes ecological problems and health issues in humans. It is "semimetallic property, is prominently toxic and carcinogenic, and is extensively available in the form of oxides or sulfides or as a salt of iron, sodium, calcium, copper, etc." It is also one of the most abundant elements on earth and its specific inorganic forms are very dangerous to living creatures (animals, plants, and humans) and

9460-517: The order of 1.5 million tonnes. The United States was the single largest producer with over 600,000 tonnes produced between 1930 and 1977. The European region follows with nearly 450,000 tonnes through 1984. It is unlikely that a full inventory of global PCB production will ever be accurately tallied, as there were factories in Poland, East Germany, and Austria that produced unknown amounts of PCBs. As of 2002 , there were still 21,500 tons of PCBs stored in

9570-663: The organism's placement within its food web . Bioaccumulation occurs when an organism stores toxicants in fatty tissues, which may eventually establish a trophic cascade and the biomagnification of specific toxicants. Biodegradation releases carbon dioxide and water as by-products into the environment. This process is typically limited in areas affected by environmental toxicants. Harmful effects of such chemical and biological agents as toxicants from pollutants , insecticides , pesticides , and fertilizers can affect an organism and its community by reducing its species diversity and abundance. Such changes in population dynamics affect

9680-458: The organizations affiliated with them by providing specialized new ideas, research, and findings. Nations at various developmental stages will find the need for different academic disciplines during different times of growth. A newly developing nation will likely prioritize government, political matters and engineering over those of the humanities, arts and social sciences. On the other hand, a well-developed nation may be capable of investing more in

9790-433: The other hand, can cause more severe symptoms such as, "mental retardation, birth defects, psychosis, autism, allergies, dyslexia, weight loss, hyperactivity, paralysis, muscular weakness, brain damage, kidney damage and may even cause death." Mercury, a shiny silver-white, can transform into a colorless and odorless gas when heated up. Mercury highly affects the marine environment and there have been many studies conducted on

9900-599: The passage of the Toxic Substances Control Act (TSCA). The utility of PCBs is based largely on their chemical stability, including low flammability and high dielectric constant. In an electric arc, PCBs generate incombustible gases. Use of PCBs is commonly divided into closed and open applications. Examples of closed applications include coolants and insulating fluids ( transformer oil ) for transformers and capacitors , such as those used in old fluorescent light ballasts, and hydraulic fluids considered

10010-524: The political science field (emphasizing the policy analysis aspect). As the twentieth century approached, these designations were gradually adopted by other countries and became the accepted conventional subjects. However, these designations differed between various countries. In the twentieth century, the natural science disciplines included: physics , chemistry , biology , geology , and astronomy . The social science disciplines included: economics , politics , sociology , and psychology . Prior to

10120-569: The recommended threshold values held by the U.S. Environmental Protection Agency (EPA). In addition, they measured the concentration of mercury found in fish living nearby in the Atrato River. Even though the concentration was determined to have a low risk factor for human health and consumption, the concentration (0.5 g/g) was above the World Health Organization's (WHO) recommended threshold. They also determined that approximately 44% of

10230-420: The ring positions ortho to (next to) the other ring, (such as PCBs 77, 126 and 169), tend to have dioxin -like properties, and generally are among the most toxic congeners. Because PCBs are almost invariably found in complex mixtures, the concept of toxic equivalency factors ( TEFs ) has been developed to facilitate risk assessment and regulation, where more toxic PCB congeners are assigned higher TEF values on

10340-469: The rings. Phase I reactions occur by adding an oxygen to either of the benzene rings by Cytochrome P450 . The type of P450 present also determines where the oxygen will be added; phenobarbital (PB)-induced P450s catalyze oxygenation to the meta-para positions of PCBs while 3-methylcholanthrene (3MC)-induced P450s add oxygens to the ortho – meta positions. PCBs containing ortho – meta and meta – para protons can be metabolized by either enzyme, making them

10450-410: The second two numbers indicate the percentage of chlorine by mass in the mixture. Thus, Aroclor 1260 is a 1200 series product and contains 60% chlorine by mass. It is a myth that the first two digits referred to the number of carbon atoms; the number of carbon atoms do not change in PCBs. The 1100 series was a crude PCB material which was distilled to create the 1200 series PCB product. The exception to

10560-440: The signing of the 1990 amendments. These amendments protected reducing acid, the ozone layer, improving air quality and toxic pollutants. The Clean Air Act was actually revised and with, support from President George H.W Bush, it was signed in. The biggest major threats that this act targets are: urban air pollution, toxic air emissions, stratospheric ozone, acid rain etc. Apart from targeting these specific areas, it also established

10670-542: The soil. Humans come in contact with lead through mining, fossil fuel burning. In burning, lead and its compounds are exposed into air, soil, and water. Lead can have different effects on the body and effects the central nervous system. Someone who has come in contact with lead can have either acute or chronic lead poisoning. Those who experience acute poisoning have symptoms such as appetite, headache, hypertension, abdominal pain, renal dysfunction, fatigue, sleeplessness, arthritis, hallucinations and vertigo." Chronic exposure on

10780-515: The specific PCB. In terms of their structure and toxicity, PCBs fall into two distinct categories, referred to as coplanar or non- ortho -substituted arene substitution patterns and noncoplanar or ortho -substituted congeners. Di- ortho -substituted, non-coplanar PCBs interfere with intracellular signal transduction dependent on calcium which may lead to neurotoxicity . ortho -PCBs can disrupt thyroid hormone transport by binding to transthyretin . Commercial PCB mixtures were marketed under

10890-717: The term "discipline" to catalog and archive the new and expanding body of information produced by the scholarly community. Disciplinary designations originated in German universities during the beginning of the nineteenth century. Most academic disciplines have their roots in the mid-to-late-nineteenth century secularization of universities, when the traditional curricula were supplemented with non-classical languages and literatures , social sciences such as political science , economics , sociology and public administration , and natural science and technology disciplines such as physics , chemistry , biology , and engineering . In

11000-514: The threshold amount for human consumption made by the Chinese Food Health Criterion. Overall, the study showed that the remediation efforts here did in fact reduce the amount of heavy metals built up in the fish. Generally speaking, the specific rate of build-up of metals in fish depends on the metal, the fish species, the aquatic environment, the time of year, and fishes' organs. For example, metals are more commonly known to be found

11110-478: The tissues of marine life like fish too. For example, its accumulation has been shown to cause neurodegeneration in cerebral regions of the brains such as those of O. mossambicus , otherwise known as Mozambique tilapia. Aluminum also decreases locomotive abilities of fishes since aluminum is thought to negatively impact with their oxygen supply. Finally, the metal causes slow responses to arousal and other environmental stimuli, overall abnormal behavior, and changes with

11220-448: The total sites around the river had a moderate level of pollution, further emphasizing that more intervention programs should be conducted to curb the seepage of mercury into the environment. This was a major concern especially since the Choco region is a biodiversity hotspot for all manner of organisms, not just humans. In the end, the highest levels of total airborne mercury were found to be in

11330-424: The twentieth century, categories were broad and general, which was expected due to the lack of interest in science at the time. With rare exceptions, practitioners of science tended to be amateurs and were referred to as "natural historians" and "natural philosophers"—labels that date back to Aristotle—instead of "scientists". Natural history referred to what we now call life sciences and natural philosophy referred to

11440-446: The universities. Finally, interdisciplinary scientific fields of study such as biochemistry and geophysics gained prominence as their contribution to knowledge became widely recognized. Some new disciplines, such as public administration , can be found in more than one disciplinary setting; some public administration programs are associated with business schools (thus emphasizing the public management aspect), while others are linked to

11550-700: The use of one's motor skills, cognition, and sight. Because of these worrying side effects, there was a study done in the Pacific coast of Columbia to assess the levels of mercury in the environment and in the people living there from gold-mining. The researchers found that the median total mercury concentration in hair measured from people living in two communities, Quibdo and Paimado, was 1.26 μ {\displaystyle \mu } g/g and 0.67 μ {\displaystyle \mu } g/g respectively. Residents in other areas of Columbia have been found to have similar levels. These levels are greater than

11660-443: Was a negative correlation observed between copper contamination and genetic diversity. Some aquatic species have evolved heavy metal tolerances. In response to high heavy metal concentrations a Dipteran species, Chironomus riparius , of the midge family, Chironomidae, has evolved to become tolerant to cadmium toxicity in aquatic environments. Altered life histories, increased cadmium excretion, and sustained growth under cadmium exposure

11770-535: Was charged against the three people for "illegally dumping PCBs along 210 miles of roadway in North Carolina." Though PCBs were banned, there are some exceptions where they are being used. The area in which it has been completely prohibited is "the manufacture, processing, distribution in commerce, and "non-enclosed" (open to the environment) uses of PCBs unless specifically authorized or exempted by EPA. "Totally enclosed" uses (contained, and therefore exposure to PCBs

11880-431: Was estimated to account for 120 kg/year of PCBs entering Lake Michigan . In 2008, concentrations as high as 35  ng /m , 10 times higher than the EPA guideline limit of 3.4 ng/m , have been documented inside some houses in the U.S. Volatilization of PCBs in soil was thought to be the primary source of PCBs in the atmosphere, but research suggests ventilation of PCB-contaminated indoor air from buildings

11990-498: Was still prevalent in the U.S. in 2016 and in Australia for some time. Because it can dissolve in water, many concerns have been raised about its potential to contaminate soil and water along the surface and ground. Various studies have been conducted to determine the impact of atrazine on wildlife. For example, studies have shown it to cause stunted growth and suppress or damage the immune and reproductive systems of aquatic life. It also

12100-544: Was that it helped further push policy areas. CEQ created environmental programs including the Federal Water Pollution Control Act, Toxic Substance Control Act , Resources Conservation and Recovery Act (RCRA and the Safe). CEQ was essential in creating the foundation for most of the "current environmental legislation except for Superfund and asbestos control legislation." Some initial impacts of NEPA pertain to

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