When we think of pollution, we often think of it as a visible problem. The term usually conjures up images of rubbish dumps and oil slicks. Most forms of pollution are invisible to the human eye and come in a variety of different forms. This week, we thought we’d look at the seven major forms of pollution and their effect on the environment.
This type of pollution refers to the contamination of bodies of water including groundwater. As all living organisms depend on water to live, the pollution of a body of water tends to affect every level of the ecosystem, including human health. Common causes of water pollution include industrial waste, insecticides, pesticides, and fertilisers, detergents and oil spills. These pollutants either work by killing off organisms through their toxicity (industrial waste, insecticides), or reducing oxygen values in the water (known as Eutrophication) by blocking out sunlight (detergents, oil).
Air is usually comprised of 78% nitrogen, 21% oxygen, 0.9% oxide gases and 0.1% inert gases. When the air becomes contaminated with other elements such as poisonous gases or particles, it can cause serious problems to human health. The most common causes of air pollution include partially combusted exhaust gases, poisonous gases which are a by-product of industry including sulphur dioxide and carbon monoxide, and carcinogenic gases released through the burning of plastic, rubber and wood. Particle contamination can also occur when a substance such as friable asbestos fibres are disturbed and released into the air. Air pollution works either by poisoning living organisms which breathe it in, or by disturbing the atmosphere and mixing with their air and clouds to cause acid rain. In the case of particle contamination, particles such as asbestos fibres become airborne and are inhaled, irritating the respiratory system and causing health conditions.
Soil can be stripped of it’s nutrients (and therefore fertility) by a number of chemical agents and when this occurs, it is known as soil pollution. Common causes of soil pollution include pesticides, insecticides, agricultural chemicals, industrial waste, and radioactive waste. Plants depend on the nutrients in the soil in order to grow, but many of these chemical compounds absorb the nitrogenous compounds present in the soil which the plants depend on. Aside from making an area barren, soil pollution is a common cause of erosion, as plants and other living organisms play an important role in keeping the soil held together. When they die off, the soil splits and begins to erode. The heavy metals which get into the soil via chemical pollution also have a devastating effect on the ecosystem as they alter the metabolism of microorganisms and arthropods living in the soil. These heavy metals become more concentrated as they move up the food chain, often wiping out predator or consumer species at the apex.
Many industries release heat energy as a by-product and once released into the environment, this thermal energy is partially responsible for global warming. Manufacturing industries release thermal energy into the air as well as into bodies of water. This in itself is not necessarily a bad thing although it can dramatically alter local ecosystems. The problem arises from the excess of carbon dioxide in our atmosphere. Carbon dioxide prevents heat from exiting the atmosphere, so the heat from the sun, combined with the excess thermal energy which is a by-product of many industries as well as vehicles cannot escape and raises the temperature of the atmosphere. Global warming is responsible for the melting of the polar ice caps which in turn have led to a rise in sea levels.
When radioactive metals disintegrate, they release beta rays which can cause a whole host of mutative diseases in living organisms, this is known as radioactive pollution. As the name suggests, radioactive pollution mostly comes from the nuclear power industry, either in the form of radioactive waste being dumped or improperly disposed of and then making its way into bodies of water, or from the accidental release of radioactive substances when a nuclear reactor is damaged. Once radioactive pollution is present in the environment, it can linger for decades, making enormous areas of land unfit for human occupation of any sort.
Noise pollution refers to an excess of unpleasant sounds emanating from industry, infrastructure, heavy machinery, transportation, and even human occupation being released into the environment. In humans, noise pollution can have a detrimental effect on both mental and physical health and has been linked to high stress levels, hearing loss, hypertension, depression, sleep disturbances and an increase in incidences of coronary artery disease. Noise pollution also reduces the amount of viable habitat for wildlife as it interferes with sounds and communication, making it difficult for animals to navigate, mate and detect predators or prey
The excessive, obtrusive, and misdirected use of light in areas of human habitation as well as in industry cause light pollution. Light pollution is defined as the alteration of natural light levels in both indoor and outdoor environments through human interference. Light pollution causes headaches, fatigue, stress and anxiety. Light pollution disrupts eco systems by confusing animal navigation, altering predator-prey relations, disrupting plant growth and pollination, and change competitor interactions.