- 1 Causes of Soil Pollution
- 1.1 A. Anthropogenic causes
- 1.1.1 1. Industrial waste
- 1.1.2 2. Excessive Use of Fertilizer
- 1.1.3 3. Use of Pesticides
- 1.1.4 4. Excessive use of plastic
- 1.1.5 5. Medical wastes
- 1.1.6 6. Composition of toxic solid metals
- 1.1.7 7. The mixture of mineral oil
- 1.1.8 8. Sewage produced in urban areas
- 1.1.9 9. The mixture of radioactive materials
- 1.1.10 10. Electronic Waste
- 1.2 B. Naturogenic Causes
- 1.3 Share this:
- 1.4 Related
- 1.1 A. Anthropogenic causes
Causes of Soil Pollution
Hello readers! I hope you all are doing well. Today, our topic is “causes of soil pollution“. ‘Pollution’ is the word with which all of us are well acquainted at present time. Pollution is such a harmful condition of the environment that affects not only human life but also every creature of the ecosystem. Our environment is getting contaminated mainly due to human activities. Among different types of pollution (like – water pollution, air pollution, and sound pollution), soil pollution is one of them and is a matter of great concern as well. Today, we will take a look at the main causes of soil pollution in this article. So, let’s dive in.
Before learning the main reasons for soil pollution, we need to know “what is soil pollution“. See, any soil is not devoid of hazardous or toxic substances that are harmful to human beings and other living creatures. But, you will not find the density of such elements in unpolluted soil that can be alarming to its adjacent ecosystem. On the other hand, when one or more such toxic components are present in the soil in large amounts, the soil becomes dangerous to living beings and it is called polluted.
Along with the advancement of human civilization, urbanization and industrialization are climbing up gradually. As a result, the amount of waste materials from factories, vehicles, agriculture, etc. is increasing uncontrollably. And by mixing with soil, this wastages toxifies the soil day by day.
Did you know that one inch of topsoil (the upper layer of soil) enriched with the most organic matter and microorganisms takes at least 100 years to form? But what do we humans do? We make them full of toxins and harmful chemicals every moment.
According to the Food and Agricultural Organization of the United Nations (FAO), the countries of Asia, Europe, and North Africa are the ones having serious aggregation of soil pollution. Currently, Bangladesh is considered to be the country having the most soil pollution in the globe. Statistics show that, on average, 8.3 million people in the world face death every year only from soil or land pollution.
Food is the most essential thing for survival. And these foods are grown in the soil, therefore, we cannot imagine our life without soil. So, the ground should always be clean and should contain full of nutrients.
But, if soil pollution continues to rise at such a rate, it will pose a big threat to all of us. Due to soil pollution, people face many deadly diseases and severe health problems. A few long-term diseases like – leukemia, cancer, etc. are caused if a man comes in contact with soil contaminated with chemicals like – gasoline and benzene. Among the most common soil pollutants, there are some hefty metals like – cadmium, lead, and arsenic that increase the chance of stroke, hypertension, and heart disease.
Though the most percentage of soil pollution occurs by chemical substances created by human activities, there are some negligible natural causes of it. So, we can divide the causes of soil pollution into two segments –
- A. Anthropogenic causes (man-made)
- B. Naturogenic causes (nature-made)
A. Anthropogenic causes
The word ‘anthropogenic’ indicates something (mainly environmental pollution and pollutants) caused by human activities. Almost every cause of soil pollution is anthropogenic i.e man-made. You will find too many processes by which people lead soil to extreme contamination. Here are the most significant man-made reasons for soil pollution:
1. Industrial waste
Industrial wastes play a vital role in polluting the soil. People have built many factories and industries due to various needs. But there is hardly any well-planned waste management in those factories and industries. Therefore, industrial wastes are directly discharged into the soil. In this way, many hazardous chemicals like Polychlorinated biphenyls (PCBs), Dioxins, benzene, methylbenzene, etc. get combined with soil. And the most important thing is that these chemicals are extremely carcinogenic to humans. Besides, these elements reduce the fertility and strength of the soil.
2. Excessive Use of Fertilizer
In the 21st century, people cannot think of farming without chemical fertilizers. In today’s agriculture, chiefly three macronutrients – nitrogen, phosphorus, and potassium-based fertilizers are used. Among the most common fertilizers, there are urea, diammonium phosphate, potassium chloride, etc. Undoubtedly these fertilizers are advantageous to boost the nutrients of plants, but they are posing a great negative impact on the land. Overuse of nitrogen-based fertilizers makes the soil acidic and the land gradually becomes uncultivable.
On the other hand, phosphorus-containing fertilizers carry a very dangerous metal – cadmium. When a phosphorus-based fertilizer is used in agriculture, cadmium makes the soil contaminated and also our food. Cadmium is such an element that is highly hazardous to human health that causes fatal diseases like – cancer. But the quantity of cadmium significantly varies in different phosphate rocks. For example, depending on the phosphate rock, SSP (Super Single Phosphate) may have a cadmium content of as low as 2 mg/kg or as high as 40 mg/kg. And you will be surprised to know that the phosphate rocks which are used to manufacture fertilizers may contain nearly 200 mg of cadmium per kg.
Except these, many other substances like – arsenic, fluoride, mercury, radioactive elements, etc. get mixed with the soil released from the fertilizers making the soil contaminated. Read Also: How to Improve Soil Fertility?
3. Use of Pesticides
Pesticide is a must-have thing in modern agriculture. Similarly, it is a must-have point in the list of the causes of soil pollution as pesticides are greatly responsible for soil pollution. When applied, pesticides mix with the soil making it contaminated. Among the most common types of pesticides used to resist the outgrowth of pests, there are – herbicides, insecticides, fungicides, rodenticides, etc.
Carbamates, Phenoxyalkyl acids, and Aliphatic acids are some examples of herbicides that are used to kill weeds and other unwanted plants. Whereas organophosphates, chlorinated hydrocarbons, and pyrethrum are the common names of insecticides that are used to kill insects.
Mercury-containing compounds, thiocarbamates, copper sulfate, etc. are used to kill parasitic fungi or control their spread and so, these are called fungicides. Rodenticides include bromethalin, zinc phosphide, strychnine, etc. which are useful to kill rodents like – rats, mice, squirrels, woodchucks, etc.
It’s needless to say that all the above-mentioned pesticides are verily dangerous pollutants of soil and we, humans, are continuously using them and bringing our own troubles.
4. Excessive use of plastic
Plastic materials have become an inseparable thing in our daily life. Alongside, they have become a great threat to the environment as well as to mankind. They, especially plastic carry bags, play a vital role in polluting the soil. People all over the world use plastic carry bags, plastic wrappers, etc. randomly and throw them here and there after one-time use.
Each year, we produce on average, 400 million tons of plastic waste. We all know that plastics are not biodegradable, i.e they do not get decomposed with the soil. And too many toxic chemicals are used to produce plastic. Owing to the leaching of substances like – phthalates, Bisphenol A (mostly familiar as BPA), fluorinated compounds, etc. from plastics, the surrounding soil becomes contaminated. When released, these toxins obstruct the growth of plants and also affect the soil fauna. More importantly, these chemicals have adverse effects on human health.
5. Medical wastes
Another significant reason behind soil pollution is biomedical waste or infirmary waste. Materials used for patient care, such as cotton, bandaids, syringes, medicines, and medical instruments are examples of medical wastes. Medical wastes also include biomolecules or organisms used in research laboratories. Only the U.S produces more than 6 million tons of medical waste every year on average.
When the management of these wastes is not done in a proper way, they become a cause of soil pollution. In most cases, medical wastes are dumped in open land. As a result, the wastes leach out harmful chemicals like – polynuclear aromatic hydrocarbons (PAHs), polychlorinated dibenzofurans (PCDFs), heavy metals, etc. Thus, the surrounding soil gets extremely contaminated with the aforesaid toxins. And beyond the shadow of a doubt, such soils are very dangerous to plants and living beings as well.
6. Composition of toxic solid metals
As I have told you beforehand, the presence of heavy metals in the soil at a large concentration causes soil pollution. When soil is polluted with one or more heavy metals, its microbial processes are highly affected and the number and activity of soil microorganisms are decreased. Along with some natural sources, man-made sources of heavy metals like – arsenic, cadmium, chromium, mercury, lead, copper, zinc, and nickel are the most in number. Man-made sources of such metals are – foundries, smelters, oil refineries, petrochemical plants, pesticide production, chemical industries, etc.
7. The mixture of mineral oil
The list of causes of soil pollution will be incomplete without the mention of mineral oils. Mineral oils are something that is contaminating the soil day by day. But, how? Ok, I am telling you.
Mineral oils can mix with soil in various ways. When mineral oils are extracted from underground, they spill around and get mixed with the soil. Another way mineral oil causes soil pollution is leakage of the pipelines through which mineral oils are transported. If there is a leakage in the pipe while transporting the oils, they exude from the pipe and contaminate the soil. Besides, the waste produced during the purification of the mineral oils can cause soil pollution if their disposal is not done in an appropriate process.
Soil pollution due to mineral oil has numerous negative impacts on living beings. By increasing carbon dioxide and hydrocarbons in the soil, mineral oil also reduces the water-holding capacity of the soil. It also greatly affects human health including the surrounding flora and fauna of the soil. Excessive concentration of mineral oils in soil lessens the quantity of phosphorus which is a significant element for plants’ growth. People living around such areas face many health problems like fatigue, nausea, headache, irritation in the eyes, and skin rashes.
8. Sewage produced in urban areas
Sewages are one of the main sources of soil pollution mainly in urban areas. In the cities, mostly in developing countries, sewage water is often discharged into open land or water bodies. And during heavy rainfall, sewage water overflows and contaminates the surrounding areas with harmful chemicals, bacteria, and heavy metals. When soil becomes contaminated by sewage, it becomes unsafe not only for plants but also for humans. Read Also: Characteristics of Sewage.
9. The mixture of radioactive materials
The list of the top 10 causes of soil pollution can not be complete without the mention of radioactive materials. The adverse effects of radioactive elements like – radium, uranium, polonium, francium, etc. are uncountable. Radioactive materials mix with soil in different ways and pollute it. The largest man-made source of radioactive materials is nuclear power plants. Other sources of such elements created by mankind are – nuclear medicines, nuclear fuel, nuclear waste, nuclear explosions, etc.
As most of the radioactive elements remain radioactive for more than 1000 to 10,000 years, they hamper the nutrient cycle of soil and make them unsuitable for agriculture. And the people of surrounding areas suffer from severe and long-term health problems like cancer and cardiovascular disease.
10. Electronic Waste
All abandoned electronic or electrical devices are called electronic waste or e-waste. They can be computers, mobile phones, or household appliances that are no longer used are considered e-waste. With the advancement of technology, the demand for various types of electronic gadgets and appliances is skyrocketing and their production is also increasing likewise.
So, those products have become cheap as well as readily available. As a result of their availability like a piece of cake, electronic devices are frequently replaced by new ones. Consequently, the amount of e-waste is on the rise day by day and the environment is facing a great threat from them. According to statistics, we generate an average of 54 metric tons of e-waste every year globally. But most of that amount of e-waste is not disposed of properly and is dumped in the open land resulting in extreme soil pollution.
These e-wastes discharge many heavy metals like – lead, cadmium, beryllium, mercury, etc. into the soil. They also contaminate the soil with substances like – POPs, PCBs, plastics, perfluorooctanoic acids (PFOAs), and flame-retardants. No need to say that these elements become very dangerous to the local fauna and flora. They affect the brain, heart, liver, kidney, and skeletal system of the human body.
B. Naturogenic Causes
No, not every cause of soil pollution is man-made. Though at a very low amount, nature also creates soil pollution and those causes of soil pollution created by nature are called naturogenic causes. Here are some main natural causes of soil pollution:
1. Trace Elements
The elements that are present in the soil at a very low concentration are called trace elements. There are two types of trace elements – essential and non-essential. Essential trace elements include copper, zinc, iron, etc. which play a significant role in the growth of plants. On the other hand, some examples of non-essential trace elements are – cadmium, arsenic, lead, mercury, etc. And these non-essential trace elements are the pollutants of soil. Rock weathering, soil erosion, volcano eruption, and dissolution of water-soluble salts mainly work as the sources of trace elements that pollute the soil.
2. Naturally occurring asbestos
A fibrous silicate mineral, asbestos is such a pollutant that is naturally present in the soil. Asbestos can directly get mixed with soil from natural resources. Some common natural origins of asbestos are – serpentinites, altered ultramafic rocks, and some mafic rocks from which asbestos is generated and mixed into the soil. Asbestos brings various health hazards to humans such as mesothelioma, asbestosis, and cancer.
3. Naturally occurring organic contaminants
Some organic pollutants come to the soil through natural causes like – wildfire, volcano eruption, etc.
There are mainly three ways through which radionuclides come to the soil and contaminate it. Cosmic Radiation, Terrestrial Radiation, and Internal Radiation are those three processes by which radioactive elements like Radium, Polonium, Cesium, Strontium, Beryllium, etc. mix with soil.