The contamination or degradation of soils impacts heavily on the health of plants. Humans are also affected in numerous ways either directly or indirectly. Polluted soil can harm humans by making contact with the soil or consuming vegetation produce from contaminated soils. Children are even more susceptible to the harms of soil pollution since they spend most of their time playing in close contact with the soil. Thus, soil pollution has a long list of effects.
Some of the main soil pollution effects are as discussed below:
- Endangering Human Health
More than 70% of the soil pollutants are carcinogenic in nature, intensifying the chances of developing cancer in the humans exposed to the polluted soils. Long-term exposure to benzene and polychlorinated biphenyls (PCBs), for instance, is linked to the development of leukemia and liver cancer respectively.
Soil pollutants can also cause skin diseases, muscular blockage, and central nervous system disorders. Humans can be affected indirectly due to bioaccumulation or food poisoning. It happens when people consume crop produce that is grown in the polluted soils or when they consume animal products that eat plants from polluted soils. As a result, humans suffer from acute illnesses and may experience premature death.
For example, high concentrations of lead or mercury in the soil can endanger the functionality of kidneys and liver. It can also hamper brain development in children and cause adverse neurological disorders.
- Economic Losses
Crops and plants grown on polluted soils can accumulate poison to an extent deemed unfit for human consumption. Consequently, it leads to enormous economic losses. In some parts of the world, heavily polluted soils with metals and chemicals such as lead, asbestos, and sulfur are considered unfavorable for crop production and cannot be used to grow crops.
The crops grown in the soils and the nearby lands are often poisoned with heavy metals and chemicals thus, discarded after harvesting because of high toxicity levels. According to China’s agricultural sector, for instance, about 12 million tons of polluted grains are subjected to disposal on an annual basis, costing Chinese farmers economic losses of up to 2.6 billion U.S. dollars.
- Air and Water Contamination
Polluted soil by natural means contributes to air contamination by discharging volatile compounds into the atmosphere. So, the more the toxic contaminants in the soil, the higher the level of toxic particles and foul gasses emitted into the atmosphere. Soil pollution can also lead to water pollution if the toxic chemicals and materials like dangerous heavy metals leach into groundwater or contaminate storm water runoff, which reaches lakes, rivers, streams, or oceans.
- Effect on Plant Life
When soils are repeatedly contaminated and accumulate large amounts of poisonous materials and chemicals, the soil reaches a point where it cannot support plant life. Soil pollutants interfere with soil chemistry, biology, and structure. When these changes occur, beneficial soil bacteria, soil microorganisms, soil nutrients, and soil chemical processes begin to deteriorate to an extent where they diminish soil fertility.
The ecological balance is lost completely. On this basis, the soil becomes unsuitable for crop survival or any other form of vegetation. If the plants die, then it means animals dependent on the plants will also die. This leads to migration of the larger animals and predators to other regions to find food supply, gradually leading to a reduction in wildlife and extinction.
Soil pollution can as well change plant metabolism and lower crop productivity. Besides, when plants take up the soil contaminants, they pass them up the food chain, endangering the health of animals and humans.
Soil pollution allows emission of relatively large quantities of nitrogen via denitrification, volatilization of ammonia, and the decomposition of organic materials in the soil. As a result, this releases sulfur compounds and sulfur dioxides into the atmosphere, causing acid rain.
In the long-run, it leads to a continuous cycle of pollution whereby the acid rain reduces soil chemistry and nutrients, which would further contribute to ecological balance disturbance and soil erosion. Furthermore, acidic conditions hinder soil ability to cushion changes in the soil PH, leading to the death of plants due to unfavorable conditions.
- Diminished Soil Fertility
The most evident and crucial element of the soil is its fertility. Once the soil is contaminated with chemicals and heavy metals or degraded due to human activities such as mining, its fertility depreciates and might even be lost entirely. The harmful chemicals and heavy metals in the soil decrease soil microbial and chemical activity.
The chemical elements can also denature active enzymes that revitalize healthy soil activities. Soil acidification as a consequence of pollution also leaches away essential natural minerals like magnesium and calcium.
- Changes in the Soil Structure
Acidification, diminished soil fertility, and death of soil organisms in the soil can lead to changes in soil structure. This is because soil microorganisms help in breaking down organic matter that promotes soil structure regarding vitality and water penetration as well as retention.
- Increase in Soil Salinity
The increase in soil salinity, salinization, is an effect of salt accumulation in the soil. Salts occur naturally in the soil. However, increased accumulations are linked to soil pollution. Irrigation and agricultural processes that discharge nitrate and phosphate deposits in the soil are the primary contributors to increasing salt levels in the soil.
Increased soil salinity makes it difficult for plants to absorb soil moisture and reduces groundwater quality. Crops and plants grown in these regions combined with other soil pollutant effects are highly poisonous and can cause severe health disorders when consumed.