Chemical fertilizers are important for the cost-effective production of commercial crops, and have been since the 1930s. With a growing population and high cost of living, a bountiful harvest ensures enough food is available for everyone at affordable prices. However, using chemical fertilizers do have their hidden dangers about which most people may not know.

Some may have some vague idea of groundwater contamination and other environmental effects, but not anything in depth. Most people are not aware, for example, that an excessive amount of nitrogen in the soil can kill off fish in nearby bodies of water. To understand these effects, we need to know exactly what chemical fertilizers are and how they work.

Why Use Fertilizers?

The purpose of any fertilizer is to increase the amount of nutrients in soil that make it more fertile and friendly to plant growth. Typically present in fertilizers are one or more of the macronutrients nitrogen, phosphorus, and potassium, or NPK. Any one of these is pretty much all a plant needs to grow, and grow fast. Other nutrients may also be present, depending on the source.

There are two main types of fertilizers, organic and chemical. As the name suggests, organic fertilizers come from organic sources such animal manure and plants. They tend to be hit-and-miss unless processed carefully, in which case they tend to be expensive. Chemical fertilizers come from inorganic materials, which undergo chemical treatments. The formulations are precise and deliberate, depending on its intended use, and they are relatively cost-effective.

At face value, you might think that chemical fertilizers give farmers more control over their crop production at the right price. You would be right, but you would also be wrong. Chemical fertilizers do allow farmers to produce more and/or high-quality crops in the short-term, but may lead to fewer or poor quality crops in the long term. This is because of the intricacies of soil health.

Much like humans, the soil needs a delicate balance of nutrients to remain healthy. While NPK can definitely help plants and crops grow, simply adding them to the soil without regard for keeping the balance can lead to unintended consequences or hidden dangers.

Environmental Issues

One of the problems with chemical fertilizers is they seep through the soil into the groundwater and other water sources, leading to contamination. Now, NPK in small quantities is non-toxic, but a lot can kill the balance of nature in various ways. Nitrogen is especially tricky.

One way is by doing exactly what it is supposed to do, which is help plants grow. The problem is it creates what experts call a dead zone. When it is in the water, it encourages the growth of plankton and other aquatic plants to excessive amounts. When they die, the process of decomposition eats up oxygen that fish and other aquatic animals need to survive. As a result, the waters closest to the land where agricultural runoff is also heaviest are empty of fish and crustaceans. This upsets the ecosystem of the area and the local fishing industry.

It would not help much to stop using chemical fertilizer in the worst hit areas. Nitrogen in the water can persist for many years, so it will continue to affect the environment even without adding more.

Another problem with nitrogen is it contributes to the greenhouse effect. Dubbed the “other greenhouse gas,” nitrogen is just as bad as carbon dioxide in global warming, but is not as famous. The main sources of nitrogen in the atmosphere in the form of nitrous oxide are power plants and cars, but using more nitrogen fertilizers than crop plants can absorb plays a significant role.

In addition, chemical fertilizers can make the topsoil acidic, because nitrogen lowers the pH of the soil. The ideal pH for maximum plant growth and crop yield is between 5.5 and 8. If the soil is too acidic (pH lower than 5.5), it will yield less crops.

The environmental issues of using chemical fertilizers are bad, and they will take many years to address. However, an immediate concern with chemical fertilizers is the effect on human health.

Human Issues

The biggest harmful effect that fertilizers have is contamination of ground water. The nitrogen present in the fertilizers breaks down into nitrates and seeps through the soil and mixes with the ground water. Since nitrogen is easily soluble in water, it can remain mixed with groundwater for decades at a time and as more and more fertilizer is added to the soil the content of nitrogen in the water increases, which further increases the harmful effects of a contaminated groundwater when it is drunk by common people.

A study conducted showed that when fertilizers are mixed with pesticide the effects are compounded. The studies showed that consumption of such foods or drinking the contaminated water increased the chances of fetal abnormalities along with abnormalities in the neurological and endocrine systems of the baby. It also showed that the child may have altered ability to learn and may be over aggressive due to the Harmful Effects of Fertilizers.

The use of urea which is extremely popular and financially feasible for farmers to use is a fertilizer, which contributes to acid rain, groundwater contamination, and depletion of ozone layer in the atmosphere due to release of nitrous oxide gas. Since the use of urea has been increasing, the Harmful Effects of urea is bound to increase in the coming decades. Groundwater contamination due to urea is known to contribute to disease like gastric cancer, goiter, birth abnormalities, hypertension; testicular cancer, and stomach cancer.

Another Harmful Effect of Fertilizers is the excessive use of nitrogen may lead to respiratory problems, cardiac disease, and several types of cancers. They also contribute to increased pollen production which is a known allergen. It also contributes to various diseases like West Nile virus, malaria, and cholera

One of the most catastrophic effects of Fertilizers is the development of a medical condition known as methemoglobinemia. This condition is found in children is known by the name of Blue Baby Syndrome. This disease develops when formula foods mixed with water which has been contaminated by fertilizers is given to the child. It causes a decrease in oxygen levels in the blood giving a blue color to the skin of the baby. It also causes lethargy, irritability and may even cause coma and in some cases death.

Excess amounts of nitrogen in groundwater, which contributes to aquatic deaths of fishes as the increase in nitrogen causes more plants to grow, which eats up the oxygen present in the water, thus starving the fishes present in it. This not only affects the aquatic ecosystem, but also affects the people whose basic food is seafood like fish and are dependent on it.