In the beginning of human history, people were nomads, they moved constantly in search of food. However, when man realized that if a special treatment of the land were carried out, his resources would not run out as easily as before, and he could stay in the same place.
Then came agriculture, with its techniques and tools of work, which largely depends on chemical studies to progress. And this progress is important in view of the growing population growth and the consequent need for greater food production.
Today, agricultural production is a highly profitable investment and companies and financiers do everything they can to increase their production. For that, some resources that help them are, for example, enriching the land with chemical fertilizers, as this contributes to improving the yield of cultivated land or recovering soils impoverished by constant use; and they also use pesticides, which make it possible to control various pests, facilitating the cultivation of monocultures.
However, these techniques used, such as the use of pesticides and fertilizers, can cause great environmental damage, especially in terms of water pollution.
The indiscriminate use of pesticides it can compromise the quality of water supplies, soil, food and the maintenance of aquatic wildlife. This is because they reach the water resources when they are applied on inclined surfaces, because, when it rains, the water washes away the particles of pesticide compounds contained in the treated soils, polluting rivers, lakes and seas.
The cultivation of monoculture favors only one type of species over others, and this causes an environmental imbalance between plant and insect populations. Some species disappear and stronger pests appear, as with the prolonged use of pesticides,you insects create resistance, which requires the application of increasing doses of pesticides.
An aggravating factor is that these compounds are bioaccumulative, that is, accumulate progressively in the food chain and are not eliminated or dissolved over time. They are not biodegradable, that is, they are resistant to biological degradation, in addition to being resistant to chemical and photolytic degradation, which is the degradation made by light. As a result, even in small concentrations they greatly affect the balance of the ecosystem.
You fertilizers they can also, when used in an excessively and poorly planned way, lead to the pollution of surface waters in rivers, lakes and dams, causing damage to the ecosystem. This is because, in general, these compounds are water solubleand have some ions like nitrate (NO31-), nitrite (NO21-), ammonium (NH41+), monoacid phosphate (HPO42-) and diacid phosphate (H2DUST41-), which are nutrients for the algae that make up the phytoplankt. With the floods dragging these fertilizers into rivers, lakes and dams, algae proliferate rapidly, at a rate higher than normal. This makes it difficult for light to enter and water to oxygenate. This situation becomes worse when these algae die, as they release a very large number of debris that are broken down by aerobic microorganisms, that is, microorganisms that use the remaining oxygen in the water, causing the death of many fish and plants aquatic. This phenomenon is called eutrophication.
This should lead us to demand prompt action from the authorities, so that agriculture can be sustainable, taking into account not only economic but also social and environmental interests, like the respect for the quality of life and water resources.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/poluicao-das-aguas-por-rejeitos-agricultura.htm
