• Soil contamination is a serious environmental threat.Arid soil image by Igor Baryshev from Fotolia.com
  
  Without soil, there is no agriculture. Without agriculture, there is no human society. Soil contamination--defined by the US Environmental Protection Agency (EPA) as either solid or liquid hazardous substances mixed with the naturally occurring soil--is a very grave problem. Soil is contaminated by a number of sources that, in the words of the EPA, "are physically or chemically attached to soil particles, or, if they are not attached, are trapped in the small spaces between soil particles."
  
  

Pesticides

• The proflific spraying of pesticides to kill insects has contaminated soil.laus image by martin schmid from Fotolia.com
  
  According to a study by Resource Centres on Urban Agriculture and Food Security, "In the 1950s, the organochlorine ( such as DDT) pesticides were widely regarded as a cheap, effective and unproblematic means by which to defeat virtually all insect pests, and they were used extensively." Because of this, pesticides were drastically over-used. The report goes on to assert that DDT has a "half-life of between 2 and 15 years and is fairly immobile in most soils." Thus it, and other organochemicals, stay in soil, are absorbed by plants, eaten by animals, and introduced to humans through meat and dairy products. According to a report on DDT by the Pesticide Action Network, "There is widespread global contamination of DDT."
  
  

Industral waste

• Industrial waste is another serious cause of soil pollution.Nuclear Dunes image by adurbin from Fotolia.com
  
  Industrial waste can contaminate soil through water, air, or direct contact. Factories emit harmful waste through smoke stacks, the residue of which often settles on soil. Liquid waste and sludge can find its way from rivers and sewage leaks to soil. To quote Indonesia's Center for Soil and Agroclimate Research and Development study "Pollution of Soil by Agricultural and Industrial Waste," "Industrial waste products may be in gas, liquid or solid form. The most important gases are carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2) and sulfur dioxide (SO2). They are produced by combustion in industry and by automobiles, and they pose a hazard to the environment." Industrial contamination is a global problem, affecting soil from the United States to Indonesia.
  
  

War

• Palestine-Isael conflicts have caused lasting impacts to both countries. While Hezbollah missiles burnt 9,000 acres of forestland in Israel, Palestinian farm soils now contain toxic metals.palestine image by NL shop from Fotolia.com
  
  According to S.M. Enzler, MSc, report "The Environmental Effects of Warface", for Lenntech, conflicts from World War I to the current war in Afghanistan have caused degrees of soil contamination. Says the report on the war in Afghanistan: "Pollution from application of explosives entered air, soil and water. One example is cyclonite, a toxic substance that may cause cancer. Rocket propellants deposited perchlorates, which damage the thyroid gland." In the fight between Russia and Chechnya, spilled oil and nuclear waste has contaminated the soil, while according to the New Weapons Committee, "The 2006 and 2009 Israeli bombings in Gaza Strip have left a high concentration of toxic metals in the soil."
  
  

Farming

• Livestock, industrial farming, and fertilizers can have harmful effects on soil.Cows image by wojciechhajduk from Fotolia.com
  
  An All Creatures report on industrial and farming soil contamination asserts that "the manure slurry of factory farms is full of heavy metals because the animals do not digest all that is placed in their feed as growth supplements. Heavy metals like cadmium, arsenic, copper and zinc are put into animal feed to help make animals grow faster." In addition to bovine waste, pig waste pollutes the soil because of the bacteria it contains, including "salmonella, campylobacter, e. coli, cryptosporidium, giardia, cholera." The effects of this type of soil contamination, which is evident in the satellite areas of most global urban centers, can be permanent. Fertilizer can cause pollution by changing the chemical make-up of the soil and altering its pH. Both acidification and the build-up of salty minerals can render soil unusable for some crops.