Soil pollution impacts the environment and human health in three ways. First, contaminants attach themselves to dry soil particles and are blown away by the wind. These particles can then be inhaled by humans, who ingest the harmless soil particle as well as the more dangerous contaminant that is attached.
Second, water dissolves some of the contaminants in the soil, either during rainy weather or through groundwater action. Humans and animals then drink this contaminated water and ingest the contaminants.
Third, plants growing on polluted soil take up contaminants from the soil and store them in plant tissue. Humans and animals eat the plants and ingest the dangerous contaminants. For the second and third cases, humans that eat contaminated animals are also exposed to even more concentrated pollutants. Understanding how soil is polluted and what the consequences are is important for starting to work toward solutions.
TL;DR (Too Long; Didn't Read)
Soil pollution is hazardous to human health through contaminated soil particles in the air, through contamination from soil in the water and from plants grown in polluted soil. Food animals that drink contaminated water or eat contaminated plants are a further, secondary source of pollutants. Soil can be contaminated from industrial activity, chemical and petroleum spills, fertilizers and pesticides used in farming, landfills and fires. The consequences of humans ingesting such pollutants can include lead poisoning, deteriorating health, allergies and reduced immune system strength. Crop yields may be reduced and plants may grow less quickly while animal health can be similarly affected. In each case, the effects are related to the toxicity of the pollutants and the concentration of the exposure.
How Soil Contamination Works
Soil contamination is often present in areas that have seen a high level of industrial activity. Oil spills or chemical spills can contribute to the level of pollution. On farmland, farmers may have used toxic pesticides or fertilizers that contain harmful chemicals. Landfills can leach all kinds of chemicals into the surrounding soils and fires often add layers of toxic ash to exposed soils.
When contaminated soil particles drift through the air or flow along with water, humans can inhale or drink the pollutants attached to the particles. Traces of polluted soil on food may be eaten as well. Any of the pollutants in soils can enter the human body in this way.
Spreading the contaminants through drinking water or food plants and animals is more limited. Soil particles are generally filtered out of drinking water, and for contaminants to pass through the filters or to enter food plants and animals, they have to be soluble in water. Many industrial chemicals are only slightly water soluble and can't be spread easily in this way.
Soil Pollution Effects
The direct effects of soil pollution negatively influence the whole social and natural environment. Plants that grow on polluted soil may have lower yields because the hazardous chemicals in the soil interfere with their growth. Animals that eat polluted soil particles or contaminated plants may also grow more slowly or succumb to disease. Human health is impacted as well.
People who ingest polluted soil particles or who eat contaminated plants and animals may be poisoned by the chemical that enters their body. For example, lead is a common contaminant for areas with intensive industrial activity, and people may exhibit signs of lead poisoning. Other chemicals cause rashes and allergies, and they may weaken the immune system. All these effects depend on the type of chemical introduced into the body, how toxic it is and what its concentration is.
Soil Pollution Consequences
As soils around the world become more polluted, the consequences for society can be severe. Food shortages are likely due to the increasingly poor yields of farms. Some chemicals may reduce the overall health of large parts of the human population, leading to increased mortality and higher medical costs. When allergies become more common, the quality of life for many people is reduced, and weak immune systems may make people more susceptible to outbreaks of infectious diseases.
Healthy, productive and pure soil is essential to a healthy ecosystem and an environmentally sound social system. Once the pervasiveness, the effects and the consequences of soil pollution are widely known, people will have to work toward finding solutions and restoring pure soils wherever possible.