| Soil pollution is defined as the build-up in soils of | | | | feels, depends upon the amount of each one in |
| persistent toxic compounds, chemicals, salts, | | | | that particular soil. The type of soil varies from |
| radioactive materials, or disease causing agents, | | | | place to place on our planet and can even vary |
| which have adverse effects on plant growth and | | | | from one place to another in our own backyard. |
| animal health. Land pollution occurs massively | | | | Soil erosion, caused by wind and rain, can change |
| during earth quakes, land slides, hurricanes and | | | | land by wearing down mountains, creating valleys, |
| floods. All cause hard to clean mess, which is | | | | making rivers appear and disappear. It is a slow |
| expensive to clean, and sometimes take years to | | | | and gradual process that takes thousands, even |
| restore the affected area. These kinds of natural | | | | millions of years. But erosion may be speeded up |
| disasters are not only a problem in that they | | | | greatly by human activities such as farming and |
| cause pollution but also because they leave many | | | | mining. Soil develops very slowly over a long |
| victims homeless. After the World War II, many | | | | period of time but can be lost too quickly. The |
| countries suffered from food shortage and this | | | | clearing of land for farming, residential, and |
| facilitated the introduction of fertilizers and other | | | | commercial use can quickly destroy soil. It speeds |
| agricultural chemicals. | | | | up the process of erosion by leaving soil exposed |
| | | | | and also prevents development of new soil by |
| Soil is a thin layer of material on the Earth's | | | | removing the plants and animals that help build |
| surface in which plants have their roots. It is | | | | humus. Today's farmers try to farm in a way |
| made up of many things, such as weathered rock | | | | that reduces the amount of erosion and soil loss. |
| and decayed plant and animal matter. Soil is | | | | They may plant cover crops or use a no-till |
| formed over a long period of time. Soil Formation | | | | method of farming. Soil is an important resource |
| takes place when many things interact, such as | | | | that we all must protect. Without soil there is no |
| air, water, plant life, animal life, rocks, and | | | | life. |
| chemicals. The formation of soil happens over a | | | | The wars that hit the earth are probably the |
| very long period of time. It can take 1000 years | | | | immediate cause of soil pollution. Not talking in the |
| or more. Soil is formed from the weathering of | | | | sense of how many people died but in that it is |
| rocks and minerals. The surface rocks break | | | | through this period that many countries found the |
| down into smaller pieces through a process of | | | | necessity to improve their living standards. After |
| weathering and is then mixed with moss and | | | | the world war two, many countries suffered |
| organic matter. Over time this creates a thin layer | | | | from food shortage and this facilitated the |
| of soil. Plants help the development of the soil. | | | | introduction of fertilizers and other agricultural |
| The plants attract animals, and when the animals | | | | chemicals. Although KNP [Potassium, Nitrogen, and |
| die, their bodies decay. Decaying matter makes | | | | Phosphorus] fertilizers have not led to soil pollution, |
| the soil thick and rich. This continues until the soil is | | | | the application of trace elements has. Pesticides |
| fully formed. The soil then supports many | | | | such as DDT [dichlorodiphenyltrichloroethane] a |
| different plants. | | | | colorless chemical pesticide, which is a potent |
| Weathering is the process of the breaking down | | | | nerve poison in insects, was first widely used to |
| rocks. There are two different types of | | | | combat diseases such as yellow fever and malaria. |
| weathering: physical weathering and chemical | | | | It was later used to control and/ or eradicate |
| weathering. In physical weathering it breaks down | | | | disease carrying and crop eating insects. DDT was |
| the rocks, but what it's made of stays the same. | | | | later on discovered to cause endangerment of |
| In chemical weathering it still breaks down the | | | | species in the same food chain as the controlled |
| rocks, but it may change what it's made of. For | | | | insects, particularly birds. DDT prevents the |
| instance, a hard material may change to a soft | | | | shelling of bird eggs and in humans causes health |
| material after chemical weathering. Soils are a | | | | threats. |
| mixture of different things; rocks, minerals, and | | | | In yet another famous war of Vietnam in 1970's |
| dead, decaying plants and animals. Soil can be | | | | was introduced another Chemical substance which |
| very different from one location to another, but | | | | had a more adverse effect than that of DDT, |
| generally consists of organic and inorganic | | | | Dioxin a chemical impurity resulting from the |
| materials, water and air. The inorganic materials | | | | production of the auxin 2,4, 5T. Dioxin is a toxic |
| are the rocks that have been broken down into | | | | chemical and was used as a defoliant by the |
| smaller pieces. The size of the pieces varies. It | | | | American army. Dioxin was a major constituent |
| may appear as pebbles, gravel, or as small as | | | | of argent orange which was applied on trees |
| particles of sand or clay. The organic material is | | | | which would then fall off reaviling enemy camps. |
| decaying living matter. This could be plants or | | | | After the war it was found that the chemical |
| animals that have died and decay until they | | | | cause congenital deformalities and mental effects |
| become part of the soil. The amount of water in | | | | to the children born to the American soldiers and |
| the soil is closely linked with the climate and other | | | | in the area over which it was applied. In minute |
| characteristics of the region. The amount of | | | | amount dioxin has the ability to cause cancer, |
| water in the soil is one thing that can affect the | | | | chloracne, miscarriage, and fetal abnormalities. |
| amount of air. Very wet soil found in a wetland | | | | Glass industries have also been responsible of soil |
| probably has very little air. The composition of the | | | | pollution. The glass industries use Arsenic to |
| soil affects the plants and therefore the animals | | | | eliminate a green colour caused by impurities of |
| that can live there. | | | | iron compounds. Because arsenic is a violent |
| Soil Profile refers to the layers of soil; horizon A, | | | | poison, yet it is widely used and therefore is a |
| B, and C. Horizon A refers to the upper layer of | | | | frequent contaminant. Arsenic is sometimes |
| soil, nearest the surface. It is commonly known as | | | | added to lead to harden it and is also used in the |
| topsoil. In the woods or other areas that have | | | | manufacture of such military poison gases as |
| not been plowed or tilled, this layer would probably | | | | lewisite and adamsite. Until the introduction of |
| include organic litter, such as fallen leaves and | | | | penicillin, arsenic was of great importance in the |
| twigs. The litter helps prevent erosion, holds | | | | treatment of syphilis. In other medicinal uses, it |
| moisture, and decays to form a very rich soil | | | | has been displaced by sulpha drugs or antibiotics. |
| known as humus. Horizon A provides plants with | | | | Lead arsenate, calcium arsenate, and Paris green |
| nutrients they need for a great life. The layer | | | | are used extensively as insecticides. |
| below horizon A, of course, has to be horizon B. | | | | Pollution of land by heavy metals is a result of the |
| Litter is not present in horizon B and therefore | | | | mining of ores to extract metals such as tin, |
| there is much less humus. Horizon B does contain | | | | silver, nickel, lead, iron, chromium and copper. Most |
| some elements from horizon A because of the | | | | of these metals occur naturally as ions in the soils. |
| process of leaching. Leaching resembles what | | | | Though some metals, such as copper, iron, and |
| happens in a coffee pot as the water drips | | | | zinc, are necessary for plant growth, it is the high |
| through the coffee grounds. Leaching may also | | | | concentration if these ions that renders the land |
| bring some minerals from horizon B down to | | | | unsuitable for plant growth. Soil pollution is widely |
| horizon C. If horizon B is below horizon A, then | | | | linked to chemical substances but irrigation is |
| horizon C must be below horizon B. Horizon C | | | | somehow linked to it as well. Soil pollution has |
| consists mostly of weatherized big rocks. This | | | | been slightly controlled by putting regulations on |
| solid rock, gave rise to the horizons above it. Soil | | | | the use of DDT and introduction of alternatives to |
| profiles look different in different areas of the | | | | it. However the task of eliminating completely soil |
| world. They are affected by climate and other | | | | pollution is not easy, third some third world |
| things. | | | | countries still utilize pollutants such as DDT as |
| Sand, silt, and clay are the basic types of soil. | | | | pesticides. Mining cannot be stopped because we |
| Most soils are made up of a combination of the | | | | are in constant need for mineral ores for different |
| three. The texture of the soil, how it looks and | | | | applications. |