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Pollution and Mammal Physiology - Literature Review Example

7 pages
1785 words
Boston College
Type of paper: 
Literature review
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Pollution is one of the worlds deadliest slow poison. This is because it plays a major role in ecosystem dysfunction and biodiversity loss. In fact, pollution in our environment poses a lot of threat to the ecosystem that we depend on and adversely affects the mammalian physiology. It is important to know that pollution in the environment comprises of trash in aquatic and terrestrial systems, pharmaceutical waste in aquatic systems, agricultural nutrient run-off, increased carbon and other chemicals in the air, leakage from landfills among processes which introduces toxic waste into the environment. Extensive laboratory studies demonstrate that a lot of pollutants can modify physiological systems in mammals. Research on human population provided solid evidence that some pollutants can influence human biological aspects such s reproduction, growth, morbidity, and mortality (Hamilton, 25). Air pollution, for instance, has been associated to increases in morbidity and mortality whereas specific pollutants, e.g., lead has been linked to increased diabetes and obesity, alterations in the character of menses, decreases in measures of sperm quality, and changed rates of sexual maturation.

Types of pollution

There are different forms of pollution including water pollution, noise pollution, air pollution, light pollution, soil pollution among others. Each of these forms has its distinctive consequences and causes. Water pollution, for example, is the contamination of several water bodies. It majorly affects the aquatic life and all other creatures that use water in their ecosystem. Some of the key causes of water pollution include pesticides, insecticides, or other chemicals that run into water systems, industrial waste that is dumped directly into these water bodies, and oil spills which is usually caused by oil rigs and oil tankers. Air pollution, on the other hand, refers to the process of contaminating the air. It is a common fact respiration is essential for all living organisms. They breathe in the air that is present in the atmosphere, and when this air is contaminated, it poses a huge threat to all living organisms. Air pollution is usually caused by the release of some poisonous gases such as carbon monoxide and sulfur dioxide into the atmosphere and burning of discarded rubber, wood, or plastic which releases carcinogenic gases into the atmosphere among other practices which contaminate air.

Impacts of air pollution on human respiratory and cardiovascular system

When air pollutants are inhaled into the body, they are consequently absorbed by the blood and moved to the heart. A broad range of biological and chemical substances in these pollutants can affect the human cardiovascular system and result in structural changes such as inflammatory reactions and necrosis degenerative. Other pollutants may even influence the contractility of the heart. In events where the damage caused by these pollutants is high, it is likely to result in fatal arrhythmias. Structural alterations in the organic systems may also influence the endocrine system. This because some air pollutants may force inflamed organs to release cytokines which may have adverse impacts on the cardiovascular system such as the reduction of metabolic efficiency and mechanical performance of the blood vessels and the heart.

It is important to know that the quality of the air we breathe in affects our lungs and the quality of our health. Atmospheric air is made of a lot of components including nitrogen, carbon dioxide, oxygen, pollutants, among other components. Inhalation of these pollutants poses a huge threat to the lungs and other body organs. In fact, the lung cells can be damaged by some air pollutants such as the free radicals, metals, and ozone. Ozone is said to affect the alveoli which are a lung component responsible for the exchange of carbon dioxide and oxygen. Furthermore, bio-activation enzymes in the airway tissues can change organic pollutants into reactive metabolites which may result in neuro-behavioral disorder, lung injuries, and some of the forms of cancer such as the breast cancer.

Mutations and Genetic Diversity

Some chemical pollutants are likely to cause genetic diversity when they make their way into animals system. According to recent research, exposure to radioactive isotopes and heavy metals from nuclear processing plants and smelter plants respectively causes an improvement in genetic diversity. In fact, the air pollution in Ontario and Hamilton which is caused by steel mills has been associated with the high rate of genetic mutations in the offspring of mice and gulls. Related research after the Chernobyl nuclear accident show increased rates of genetic mutation in rodent and bird populations. Heavy metals such as lead have been associated with DNA damage in mammal and bird populations.

Asymmetry is a physical alteration which shows genetic abnormality (Clark, 48). Since of the early 1990s, body symmetry has always been used to demonstrate developmental and genetic regularity. It is imperative to understand that pollution causes many physical challenges in animals, including high rates of infections such as cancer, changed hormone levels, and problems with reproduction. Environmental pollution is said to responsible for asymmetry. In fact, research conducted on Zebra finches and swallows indicated that asymmetry happens in all parts of the body and results in decreased survival rates in mammals.

Impacts of environmental pollutants on the reproduction of mammals

Environmental pollutants comprise of an extensive range of heavy metals and synthetic organic components which are distributed throughout the environment, often at low concentrations. Although the concentrations of these pollutants are always low in the environment to make any significant impact especially when acting in isolation, the combination of several environmental pollutants, on the other hand, can have adverse effects on the physiological systems of mammals. In sheep, for example, organs that are often affected by environmental pollutants include bone, pituitary gland and hypothalamus, testis, and ovary. These results indicate that environmental pollutants hugely affects the vital body organs that are responsible for reproduction in mammals such as the ovaries. The female animals who have been exposed to toxic chemicals tend to suffer from a lot of reproductive health problems such spontaneous abortion and shrunken ovaries. Scientists appear to agree on the fact that toxic chemicals which are also referred to as endocrine disruptors adversely affects the reproductive system of mammals. Majority of studies have also link environmental pollution with the issue of falling sperm counts in human males. Although, there is inadequate evidence to justify this argument multiple observations on domestic animals report that environmental pollutants such as anti-androgenic EDCs had adverse impacts on the developing testis. Moreover, Rodent studies indicate that gene expression, differentiation, and mammary development can be affected by environmental pollutants particularly before and around puberty. Also, related research on the mammary tissue of sheep exposed to environmental pollutants such as sewage sludge revealed alterations in the tissue structure.

Effects of air pollution on the nervous system of the Mammals

Air pollution affects the mammals nervous system through a wide variety of inflammatory, molecular and cellular inflammatory pathways that directly handles damage brain structures. Evidence from recent experimental, clinical, observational, and epidemiological studies indicate that neurological diseases such as Parkinsons disease (PD), Alzheimers disease (AD) and stroke are strongly linked to air pollution. It is also argued from the observational and epidemiological view that increased exposure to air pollutants results in the occurrence of neurodegenerative conditions, especially in events where a person is extremely exposed to the contaminants. Air pollutants affect the central nervous system in two ways, in primary form and secondary form. Primary form involves transporting nanosized elements into the nervous system whereas the secondary form includes systemic inflammations that affect the nervous system. Either of these impacts occurs as a result of toxic compounds that are found in the air pollutants. Systemic inflammations are often followed by the production of cytokines which are pro-inflammatory such as the tumor necrosis factor alpha (Press, 496). These cytokines can disrupt the blood-brain barrier integrity and most importantly activate cerebral endothelial cells. Huge amounts of engineered nanomaterials and nanoparticles are said to contribute to high levels of air pollution. While the cardiorespiratory impacts of air pollution have been largely studied, limited research has been conducted on the impacts of air pollution on the central nervous system. Stroke, for instance, is one of the most common central nervous system disorders which can occur due to environmental pollution. An association between stroke and air pollution was first established after the Great London Fog. However, similar outcomes have been identified in other geographical locations such as Korea, Taiwan, France, UK, USA, Sweden, Italy, Japan, and Canada. Senior women and people were seen as the group that was more vulnerable to the impacts of the air pollutants.

The immune system and Airborne pollutants

The interaction between the immune system and the airborne pollutants results in very adverse consequences. Airborne pollutants enter into the body of the mammals through liquid droplets (nitrogen dioxide, sulfuric acid), volatile gas (benzene, ozone) or particulate matter (aromatic hydrocarbons, diesel exhaust) (Air Pollution and Health Effects, 107). Pollutants in the volatile gas such as the ozone have been linked to cardiovascular and pulmonary challenges and deaths. Moreover, it can affect the lungs making them more vulnerable to diseases. Researchers used mice to study the impacts of unhealthy pollutants on the immune system and discovered that these pollutants increase lung injuries and cell deaths in the immune system cells.

Pollution and Animal deaths

Pollution poses a lot of adverse effects on biodiversity including animal deaths. Neurological effects and reproductive system failures are two of the most common problems for both animals and humans. However, adverse contamination of the environment may lead to deaths of animals and plants. Oil spills, for instance, results in water pollution and affects the marine wildlife even causing deaths of these animals. In 2016, it was noted that over a hundred thousand seabirds died after the Exxon Valdez oil spill. In addition to the sudden deaths of marine animals caused by toxicity of oil, oil spills affects the health of the animals. Heavy metals which come from metal refining, mining, water-waste, and burning of fossil fuels often cause liver damage, neurological damage, and muscle atrophy which ultimately leads to deaths. Furthermore, it is evident that pollution is causing animals extinction especially noise pollution is causing the extinction of marine animals. Sound waves from sonar devices, oil rigs, and ships can travel a very long distance disrupting hunting, reproduction patterns, communication, and migration of a lot of marine animals. The deafening noise of oil and gas explorations causes devastating impacts to the sea life by disrupting their ecosystem. Acid rain is also another way environmental pollution can cause deaths to animals and loss of biodiversity. It is caused by the release of nitrogen and sulfur into the atmosphere. When these two chemical elements combine with other atmospheric elements, acid rain is formed. Acid rain pollutes water bodies such as tributaries, pon...

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