Pollution Of Our Nature 2

Posted: May 23, 2011 in უცხოური

pollution of nature Water Pollution

Water pollution occurs mostly, when people overload the water environment such as streams, lakes, underground water, bays or seas with wastes or substances harmful to living beings.

Water is necessary for life. All organisms contain it, some drink it and some live in it. Plants and animals require water that is moderately pure, and they cannot survive, if water contains toxic chemicals or harmful microorganisms. Water pollution kills large quantity of fish, birds, and other animals, in some cases killing everything in an affected area.

Pollution makes streams, lakes, and coastal waters unpleasant to swim in or to have a rest. Fish and shellfish harvested from polluted waters may be unsafe to eat. People who polluted water can become ill, if they drink polluted water for a long time, it may develop cancer or hurt their future children.

The major water pollutants are chemical, biological, and physical materials that lessen the water quality. Pollutants can be separated into several different classes:

The first class is petroleum products: oil, fuel, lubrication, plastics. The petroleum products get into water by accidental spills from ships, tanker trucks and when there are leaks from underground storage tanks. Many petroleum products are poisonous for animals. Spilled oil damages the feathers of birds and the fur of animals, often it causes death.

The second class is pesticides and herbicides. There are chemicals used to kill harmful animals and plants. If they penetrate into streams, rivers, lakes, these chemicals can be very dangerous. The chemicals can remain dangerous for a long time. When an animal eats a plant that’s been treated with it, the poisons are absorbed into the tissues and organs of the animals.

When other animals feed on a contaminated animal, the chemicals are passed up to them. As it goes up through the food chain, the chemical becomes more harmful, so animals at the top of the food chains may suffer cancers, reproductive problems, and death. Nitrates can cause a lethal form of anemia in infants.

The third class are heavy metals, such as, mercury, selenium, uranium, radium, cesium, etc. They get into the water from industries, automobile exhausts, mines, and natural soil. Heavy metals also become more harmful as they follow the food chain. They accumulate in living being’s cells and when they reach high levels of concentration in the organism, they can be extremely poisonous, or can result in long-term health problems. They can sometimes cause liver and kidney damage.

The fourth class is fertilizers and other nutrients used to promote plant growth on farms and in gardens.

The fifth class is infectious organisms and pathogens. They enter water through sewage, storm drains, runoff from farms, etc.

The last one is thermal pollution. Water is often taken from rivers, lakes or seas to be used in factories and power plants. The water is usually returned to the source warmer than when it was taken. Even a small temperature change in a body of water can drive away the fish and other species that were originally there, and attract other species in place of them. It breaks a balance and can cause serious circumstances in future.

LAND

land pollution, the deposition of solid or liquid waste materials on land or underground in a manner that can

contaminate the soil and groundwater, threaten public health, and cause unsightly conditions and nuisances.

The waste materials that cause land pollution are broadly classified as municipal solid waste (MSW, also called municipal refuse), construction and demolition (C&D) waste or debris, and hazardous waste. MSW includes nonhazardous garbage, rubbish, and trash from homes, institutions (e.g., schools), commercial establishments, and industrial facilities. Garbage contains moist and decomposable (biodegradable) food wastes (e.g., meat and vegetable scraps); rubbish comprises mostly dry materials such as paper, glass, textiles, and plastic objects; and trash includes bulky waste materials and objects that are not collected routinely for disposal (e.g., discarded mattresses, appliances, pieces of furniture). C&D waste (or debris) includes wood and metal objects, wallboard, concrete rubble, asphalt, and other inert materials produced when structures are built, renovated, or demolished. Hazardous wastes include harmful and dangerous substances generated primarily as liquids but also as solids, sludges, or gases by various chemical manufacturing companies, petroleum refineries, paper mills, smelters, machine shops, dry cleaners, automobile repair shops, and many other industries or commercial facilities. In addition to improper disposal of MSW, C&D waste, and hazardous waste, contaminated effluent from subsurface sewage disposal (e.g., from septic tanks) can also be a cause of land pollution.

Soil consists of a mixture of unconsolidated mineral and rock fragments (gravel, sand, silt, and clay) formed from natural weathering processes. Gravel, sand, and silt are relatively coarse-grained bulky particles, while clay particles are very small and platelike in shape and have a strong affinity for water. Gravel and sand formations are porous and permeable, allowing the free flow of water through the pores or spaces between the particles. Silt is much less permeable than sand or gravel, because of its small particle and pore sizes, while clay is virtually impermeable to the flow of water, because of its platelike shape and molecular forces. The permeability of soil formations underlying a waste disposal site is of great importance with regard to land pollution. The greater the permeability, the greater the risks from land pollution.

Until the mid-20th century, solid wastes were generally collected and placed on top of the ground in uncontrolled “open dumps,” which often became breeding grounds for rats, mosquitoes, flies, and other disease carriers and were sources of unpleasant odours, windblown debris, and other nuisances. Dumps can contaminate groundwater as well as pollute nearby streams and lakes. A highly contaminated liquid called leachate is generated from decomposition of garbage and precipitation that infiltrates and percolates downward through the volume of waste material. When leachate reaches and mixes with groundwater or seeps into nearby bodies of surface water, public health and environmental quality are jeopardized. Methane, a poisonous and explosive gas that easily flows through soil, is an eventual by-product of the anaerobic (in the absence of oxygen) decomposition of putrescible solid waste material. Open dumping of solid waste is no longer allowed in many countries. Nevertheless, leachate and methane from old dumps continue t

Soil contamination

Excavation showing soil contamination at a disused gasworks.

Soil contamination or soil pollution is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment.

This type of contamination typically arises from the rupture of underground storage tanks, application of pesticides, percolation of contaminated surface water to subsurface strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. This occurrence of this phenomenon is correlated with the degree of industrialization and intensities of chemical usage.

The concern over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapors from the contaminants, and from secondary contamination of water supplies within and underlying the soil. Mapping of contaminated soil sites and the resulting cleanup are time consuming and expensive tasks, requiring extensive amounts of geology, hydrology, chemistry, computer modeling skills, and GIS in Environmental Contamination.

It is in North America and Western Europe that the extent of contaminated land is most well known, with many of countries in these areas having a legal framework to identify and deal with this environmental problem; this however may well be just the tip of the iceberg with developing countries very likely to be the next generation of new soil contamination cases.

The immense and sustained growth of the People’s Republic of China since the 1970s has exacted a price from the land in increased soil pollution. The State Environmental Protection Administration believes it to be a threat to the environment, to food safety and to sustainable agriculture. According to a scientific sampling,150 million mi (100,000 square kilometers) of China’s cultivated land have been polluted, with contaminated water being used to irrigate a further 32.5 million mi (21,670 square kilometers) and another 2 million mi (1,300 square kilometers) covered or destroyed by solid waste. In total, the area accounts for one-tenth of China’s cultivatable land, and is mostly in economically developed areas. An estimated 12 million tonnes of grain are contaminated by heavy metals every year, causing direct losses of 20 billion yuan (US$2.57 billion).

Causes

This type of contamination typically arises from the rupture of underground storage tanks, application of pesticides, percolation of contaminated surface water to subsurface strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. This occurrence of this phenomenon is correlated with the degree of industrialization and intensities of chemical usage.

Treated sewage sludge, known in the industry as biosolids, has become controversial as a fertilizer to the land. As it is the byproduct of sewage treatment, it generally contains contaminants such as organisms, pesticides, and heavy metals than other soil.

There is also controversy surrounding the contamination of fertilizers with heavy metals; a series of newspaper articles in the Seattle Times made the issue a "national focus" in the United States, and culminated in a book called Fateful Harvest.

Health effects

Contaminated or polluted soil directly affects human health through direct contact with soil or via inhalation of soil contaminants which have vaporized; potentially greater threats are posed by the infiltration of soil contamination into groundwater aquifers used for human consumption, sometimes in areas apparently far removed from any apparent source of above ground contamination.

Health consequences from exposure to soil contamination vary greatly depending on pollutant type, pathway of attack and vulnerability of the exposed population. Chronic exposure to chromium, lead and other metals, petroleum, solvents, and many pesticide and herbicide formulations can be carcinogenic, can cause congenital disorders, or can cause other chronic health conditions. Industrial or man-made concentrations of naturally-occurring substances, such as nitrate and ammonia associated with livestock manure from agricultural operations, have also been identified as health hazards in soil and groundwater.

Chronic exposure to benzene at sufficient concentrations is known to be associated with higher incidence of leukemia. Mercury and cyclodienes are known to induce higher incidences of kidney damage, some irreversible. PCBs and cyclodienes are linked to liver toxicity. Organophosphates and carbamates can induce a chain of responses leading to neuromuscular blockage. Many chlorinated solvents induce liver changes, kidney changes and depression of the central nervous system. There is an entire spectrum of further health effects such as headache, nausea, fatigue, eye irritation and skin rash for the above cited and other chemicals. At sufficient dosages a large number of soil contaminants can cause death by exposure via direct contact, inhalation or ingestion of contaminants in groundwater contaminated through soil.

Ecosystem effects

Not unexpectedly, soil contaminants can have significant deleterious consequences for ecosystems. There are radical soil chemistry changes which can arise from the presence of many hazardous chemicals even at low concentration of the contaminant species. These changes can manifest in the alteration of metabolism of endemic microorganisms and arthropods resident in a given soil environment. The result can be virtual eradication of some of the primary food chain, which in turn have major consequences for predator or consumer species. Even if the chemical effect on lower life forms is small, the lower pyramid levels of the food chain may ingest alien chemicals, which normally become more concentrated for each consuming rung of the food chain. Many of these effects are now well known, such as the concentration of persistent DDT materials for avian consumers, leading to weakening of egg shells, increased chick mortality and potential extinction of species.

Effects occur to agricultural lands which have certain types of soil contamination. Contaminants typically alter plant metabolism, most commonly to reduce crop yields. This has a secondary effect upon soil conservation, since the languishing crops cannot shield the Earth’s soil mantle from erosion phenomena. Some of these chemical contaminants have long half-lives and in other cases derivative chemicals are formed from decay of primary soil contaminants.

Pollution effects are indeed many and wide-ranging.

There is no doubt that excessive levels of pollution are causing a lot of damage to human & animal health, plants & trees including tropical rainforests, as well as the wider environment.

Playing With Pollution

All types of pollution – air, water and soil pollution – have an impact on the living environment.

The effects in living organisms may range from mild discomfort to serious diseases such as cancer to physical deformities; ex., extra or missing limbs in frogs.

Experts admit that pollution effects are quite often underestimated and that more research is needed to understand the connections between pollution and its effects on all life forms.

Environmental Pollution Effects on Humans

We know that pollution causes not only physical disabilities but also psychological and behavioral disorders in people.

We are discussing the effects of air pollution and specific air pollutants in more detail in the Air Pollutants article.

The following pollution effects on humans have been reported:

Air Pollution Effects (1, 2)

Reduced lung functioning

Irritation of eyes, nose, mouth and throat

Asthma attacks

Respiratory symptoms such as coughing and wheezing

Air Pollution in Philippines

Photo: Jim D Stitch

Increased respiratory disease such as bronchitis

Reduced energy levels

Headaches and dizziness

Disruption of endocrine, reproductive and immune systems

Neurobehavioral disorders

Cardiovascular problems

Cancer

Premature death

We discuss effects of air pollution in more detail here.

Water Pollution Effects (3)

Waterborne diseases caused by polluted drinking water:

Typhoid

Amoebiasis

Giardiasis

Ascariasis

Hookworm

Waterborne diseases caused by polluted beach water:

Rashes, ear ache, pink eye

Respiratory infections

Hepatitis, encephalitis, gastroenteritis, diarrhoea, vomiting, and stomach aches

Conditions related to water polluted by chemicals (such as pesticides, hydrocarbons, persistent organic pollutants, heavy metals etc):

Water Pollution, California

Photo: Caleb Coppola

Cancer, incl. prostate cancer and non-Hodgkin’s lymphoma

Hormonal problems that can disrupt reproductive and developmental processes

Damage to the nervous system

Liver and kidney damage

Damage to the DNA

Exposure to mercury (heavy metal):

In the womb: may cause neurological problems including slower reflexes, learning deficits, delayed or incomplete mental development, autism and brain damage

In adults: Parkinson’s disease, multiple sclerosis, Alzheimer’s disease, heart disease, and even death

Other notes:

Water pollution may also result from interactions between water and contaminated soil, as well as from deposition of air contaminants (such as acid rain)

Damage to people may be caused by fish foods coming from polluted water (a well known example is high mercury levels in fish)

Damage to people may be caused by vegetable crops grown / washed with polluted water (author’s own conclusion)

Soil Pollution Effects (4)

Causes cancers including leukaemia

Soil and Water Pollution,

Kenya

Photo: Tom Maruko

Lead in soil is especially hazardous for young children causing developmental damage to the brain

Mercury can increase the risk of kidney damage; cyclodienes can lead to liver toxicity

Causes neuromuscular blockage as well as depression of the central nervous system

Also causes headaches, nausea, fatigue, eye irritation and skin rash

Other notes:

Contact with contaminated soil may be direct (from using parks, schools etc) or indirect (by inhaling soil contaminants which have vaporized)

Soil pollution may also result from secondary contamination of water supplies and from deposition of air contaminants (for example, via acid rain)

Contamination of crops grown in polluted soil brings up problems with food security

Since it is closely linked to water pollution, many effects of soil contamination appear to be similar to the ones caused by water contamination

An Extreme Oil Pollution Case

Pollution of pristine Ecuador rainforest by Texaco / Chevron oil corporation represents perhaps one of the most outrageous cases of oil pollution ever.

Some levels of pollutants left by the company on its sites of oil exploration have been calculated to exceed the US safety standards by as much as 1,000 times, causing such side effects as children born with fused fingers and deformed eyes, high cancer rates, etc.

For more details, check out the Oil Pollution of Ecuador Rainforest article.

Environmental Pollution Effects on Animals

Effects of Pollution on Animals – Air Pollution (5)

Acid rain (formed in the air) destroys fish life in lakes and streams

Excessive ultraviolet radiation coming from the sun through the ozone layer in the upper atmosphere which is eroded by some air pollutants, may cause skin cancer in wildlife

Ozone in the lower atmosphere may damage lung tissues of animals

Effects of Pollution on Animals – Water Pollution (6)

Nutrient pollution (nitrogen, phosphates etc) causes overgrowth of toxic algae eaten by other aquatic animals, and may cause death; nutrient pollution can also cause outbreaks of fish diseases

Chemical contamination can cause declines in frog biodiversity and tadpole mass

Oil pollution (as part of chemical contamination) can negatively affect development of marine organisms, increase susceptibility to disease and affect reproductive processes; can also cause gastrointestinal irritation, liver and kidney damage, and damage to the nervous system

Mercury in water can cause abnormal behavior, slower growth and development, reduced reproduction, and death

Persistent organic pollutants (POPs) may cause declines, deformities and death of fish life

Too much sodium chloride (ordinary salt) in water may kill animals (7)

Other notes:

We also assume that some higher forms of non-aquatic animals may have similar effects from water pollution as those experienced by humans, as described above

Effects of Pollution on Animals – Soil Pollution (8)

Can alter metabolism of microorganisms and arthropods in a given soil environment; this may destroy some layers of the primary food chain, and thus have a negative effect on predator animal species

Small life forms may consume harmful chemicals which may then be passed up the food chain to larger animals; this may lead to increased mortality rates and even animal extinction

Environmental Pollution Effects on Trees and Plants

Air Pollution (9)

Trees Damaged by Acid Rain

Photo: Lindley Ashline

Acid rain can kill trees, destroy the leaves of plants, can infiltrate soil by making it unsuitable for purposes of nutrition and habitation

Ozone holes in the upper atmosphere can allow excessive ultraviolet radiation from the sun to enter the Earth causing damage to trees and plants

Ozone in the lower atmosphere can prevent plant respiration by blocking stomata (openings in leaves) and negatively affecting plants’ photosynthesis rates which will stunt plant growth; ozone can also decay plant cells directly by entering stomata

Water Pollution

May disrupt photosynthesis in aquatic plants and thus affecting ecosystems that depend on these plants (10)

Terrestrial and aquatic plants may absorb pollutants from water (as their main nutrient source) and pass them up the food chain to consumer animals and humans

Plants may be killed by too much sodium chloride (ordinary slat) in water (11)

Plants may be killed by mud from construction sites as well as bits of wood and leaves, clay and other similar materials (12)

Plants may be killed by herbicides in water; herbicides are chemicals which are most harmful to plants (13)

Soil Pollution

May alter plant metabolism and reduce crop yields (14)

Trees and plants may absorb soil contaminants and pass them up the food chain

Environmental Pollution Effects on Wider Environment

Apart from destroying the aquatic life in lakes and streams, acid rain can also corrode metals, damage surfaces of buildings and monuments, and cause soil acidification.

Pollution of water may cause oxygen depletion in marine environments and severely affect the health of whole ecosystems. (15)

Some Notes on Pollution Effects

Miguel A. Santos notes that a very important aspect of the effect of pollution is its dose (or concentration) required to cause environmental damage. (16)

He defines pollution response as “the change in the effect of a pollutant in response to a change in its concentration”. (17)

In this respect, he identifies 3 different types of response evoked by the environment to different pollution concentrations: (18)

Linear effect

Greater-than-linear effect

Threshold effect

In the linear effect, environmental damage increases linearly with pollution concentrations. In other words, “ the total damage or risk is directly proportional to the accumulated exposure”.

This effect occurs with radioactive substances as well as mercury, lead, cadmium and asbestos.

In the greater-than-linear effect, environmental damage increases with an increase in pollution concentrations but at a decreasing rate. This means that, as pollution concentrations continue to increase the environmental damage will continue to decrease.

This is the case with thermal pollution.

In the threshold effect, pollution produces no effect until a certain threshold in pollution concentrations is achieved. In other words, “so long as a given threshold is not exceeded, the damage from pollution would be completely repaired as quickly as it is produced”.

This effect is found with biodegradable pollutants.

It is also important to mention synergistic effects of pollutants on the environment. While interacting with each other, pollutants can produce greater impacts than when acting individually.

A good example of that is a synergy between asbestos exposure and smoking in causing lung cancer.

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