Edited By Team Careers360 | Updated on Dec 20, 2024 06:01 PM IST
Environmental Chemistry deals with the chemical processes which occur in the natural environment and their impacts on ecosystems and human life. It focuses on understanding pollutants in air, water, and soil, their sources, chemical reactions, and harmful effects. Topics such as atmospheric pollution, water quality, soil contamination, and biochemical oxygen demand highlight the importance of maintaining ecological balance. In this article we will discuss the science behind pollution, the standards for safe drinking water, and sustainable solutions to mitigate environmental degradation, emphasizing the critical role chemistry plays in addressing environmental challenges.
Atmospheric pollutants are substances that contaminate the air and affect the environment and human health. Key pollutants include oxides of nitrogen (NOx), sulfur dioxide (SO₂), carbon monoxide (CO), and particulate matter. Reactions between these pollutants can lead to the formation of smog, acid rain, and greenhouse gases. For example, NO₂ reacts with sunlight and hydrocarbons to produce photochemical smog, which irritates the respiratory system and reduces visibility.
Water Pollution Causes
Water pollution occurs due to the introduction of harmful substances into water bodies. Industrial discharge, agricultural runoff containing fertilizers and pesticides, oil spills, and untreated sewage are primary water pollution causes. These pollutants can harm aquatic ecosystems, disrupt food chains, and pose health risks to humans through contaminated drinking water.
Biochemical Oxygen Demand (BOD)
Biochemical Oxygen Demand is a measure of the amount of oxygen required by microorganisms to decompose organic matter in water. High BOD levels indicate significant pollution from organic waste, leading to oxygen depletion and harm to aquatic life. It serves as an essential indicator of water quality.
Drinking water standards ensure the safety of water for human consumption. Parameters like pH, hardness, the presence of harmful chemicals (e.g., nitrates, heavy metals), and microbial contamination are regulated.
Soil Pollution
Soil pollution is caused due to excessive use of chemical fertilizers, pesticides, industrial waste, and improper disposal of non-biodegradable materials. Contaminated soil loses fertility, affects crop quality, and poses threats to ecosystems and human health through food chains. Sustainable agricultural practices and waste management are crucial to combat soil pollution.
Environmental pollution: It is the condition when unwanted and harmful substances add on in the environment and create changes to it which is dangerous to all sorts of life. A substance which is responsible for pollution is known as a pollutant. Pollutants are degradable, some are easily degradable like discarded vegetables and some cannot be degraded by natural processes like DDT.
Atmospheric pollution: The atmosphere is divided into various layers. All these various layers have different densities and height. The bottom layer of the atmosphere in which the humans live is known as the troposphere. This region is dusty, containing water vapour and clouds. Above this layer, there is stratosphere. This layer contains, dinitrogen, dioxygen, and ozone. The ozone present in this region protects us from the harmful ultraviolet radiations from the sun. Atmospheric pollution is the study of the pollution in these two layers.
Tropospheric pollution is caused by the presence of undesired solid and gaseous particles. Some of the gaseous and particulate pollutants are as follows: (i) Gaseous air pollutants: These pollutants are nitrogen and carbon, oxides of sulphur, ozone, hydrogen sulphide, etc. (ii) Particulate pollutants: These are dust, fumes, smog, smoke, etc.
Global Warming and the Greenhouse Effect: There are some of the gases carbon dioxide, methane, CFCs and water vapour than are responsible for global warming. Most of the sun’s energy when fall on the earth’s surface, then it is absorbed by the earth’s surface, only some of it goes back to the environment. Now, these gases like carbon dioxide, methane, CFCs, etc have the capacity to absorb this heat. In today’s time, the concentration of these gases especially of carbon dioxide is increasing due to which these gases are trapping more heat and thus the temperature of the environment is increasing. If this condition remains for long then it has very hazardous effects in the future like the melting of icebergs, flooding of low lying areas, etc.
Acid Rain: Acid rain is the situation when the oxides of nitrogen and sulphur dissolve with the rainwater. Burning of fossil fuels like coal and oil, etc. emit these oxides of sulphur and nitrogen. This acid rain very harmful to nature. If it is dissolved in the lakes or rivers then it is harmful to aquatic life. It is also harmful to agriculture, trees, and plants as it dissolves all the nutrients and hampers their growth. It is also harmful to buildings and other kinds of structures. Taj Mahal is getting affected by this acid rain.
Water Pollution: Water pollution is a very major problem in India and in fact worldwide. Today the condition is such that we can not even find the pure water around us. All rivers, ponds, lakes, streams, oceans have been polluted aggressively. Basically, there are important sources of water pollution as mentioned below.
Pathogens: Pathogens are disease-causing microorganisms that enter into the water from various sources like sewage, industrial waste or animal excreta. These pathogens enter into the water and cause the water polluted and not usable. Some common pathogens are Escherichia coli and streptococcus faecalis.
Organic wastes: These are wastes such as leaves, woods, grass, etc. that entered into the water and pollute it. Basically, these organic materials entered into the water and rotten there and thus create the pollution. Phytoplanktons algae are also sources of water pollution.
Chemical pollutants: These are chemicals wasted that entered into the water and pollute it. Many times these chemicals are soluble in water but these chemicals also contain heavy metals like cadmium, mercury, nickel, etc. These heavy metals are dangerous for living beings and are the major cause of pollution.
Soil Pollution: Soil pollution is caused by excessive and consistent use of pesticides, insecticides, and herbicides. In agriculture, farmers use these substances to protect their crops from harmful insects. These fertilizers at that very moment found to be useful and effective but they are water-insoluble and non-biodegradable, thus they get collect in the soil and pollute it. Overuse of these fertilizers makes the soil ineffective for agriculture. The concentration of these toxic fertilizers increases buys 10 folds at each higher trophic level. Thus, when they reach to the human, they are in their most dangerous form.
Industrial Waste All those waste materials that are released by the industries and harmful to the environment are known as industrial waste. Industrial waste are of two types i.e, biodegradable waste and non-biodegradable waste. Biodegradable waste is easy to handle because of a certain amount of time, these wastes get degraded but non-biodegradable wastes if not disposed of with proper treatment then it can cause various problems to the environment to the living beings. Biodegradable wastes are released by cotton mills, textile factories, paper mills, etc. Non-biodegradable wastes are released by various sources such as thermal power plant, iron, and steel plants, industries manufacturing aluminium, fertilizers industries, etc.
Strategies to Control Environmental Pollution After studying all these types of pollution, we understand that there is an urgent need of strategies to control these environmental pollutions. There are various kinds of wastes we have already studied. The domestic wastes are first collected in the bins. These bins are then taken to the disposal site. At this site, all these wastes are separated out into biodegradable and non-biodegradable wastes. Non-biodegradable wastes are sent for recycling and biodegradable wastes are converted into compost.
If these wastes are not collected properly then they get collected to sewers. Thus they choke the sewers. If these wastes are freely deposited on the streets then cattle eat them. Thus all these domestic wastes should be properly disposed and treated.
Green Chemistry Green chemistry is the science which motivates us to think and utilize the existing knowledge to produce the products with minimum adverse effects on the environment.
Green chemistry in daily life: (i) Dry cleaning of clothes: Initially, Tetrachloroethene was used for dry cleaning of clothes. But it was found that this compound pollutes the groundwater and is carcinogenic. Now it is replaced by liquified carbon dioxide because this causes less harm to groundwater. (ii) Bleaching of paper: Initially, chlorine gas was used for bleaching paper. Nowadays, hydrogen peroxide is used with a suitable catalyst for bleaching. (iii) Synthesis of chemicals: Ethanal is now commercially prepared by one-step oxidation of ethene.
How to prepare for Environmental Chemistry?
This chapter is the part of inorganic chemistry. This is a very basic chapter and also possess low weightage of marks in exams.
For preparing this chapter, there is no need of any pre-requisite chapter. Thus prepare it freshly and actively. Most of the concepts of this chapter are very easy as you are already familiar from your earlier classes
In the nutshell, it can be said that although this chapter is not very long, it is a very simple and straightforward one. So always say a "Big YES" to this chapter.
Prescribed Books for Environmental Chemistry
For this chapter, first, the NCERT book is best for initial level preparation as well as for board exams. Now, after this, if you want to prepare for competitive exams like JEE and NEET, then these are the best books for you - O.P Tandon. Meanwhile, in the preparation, you must continuously give the mock tests for the depth of knowledge. Our platform will help you to provide with the variety of questions for deeper knowledge with the help of videos, articles and mock tests.
Environmental Chemistry is the study of chemical processes in the environment, including the sources, effects, and mitigation of pollutants in air, water, and soil.
2.What is Biochemical Oxygen Demand (BOD)?
BOD measures the amount of oxygen required by microorganisms to decompose organic matter in water. High BOD levels indicate severe water pollution, which can harm aquatic life.
3.What are the primary causes of water pollution?
Water pollution is caused by industrial discharges, agricultural runoff, sewage, oil spills, and plastic waste. These contaminants degrade water quality, harming ecosystems and making water unsafe for consumption.
4.How does soil pollution occur?
Soil pollution occurs due to excessive use of pesticides, industrial waste disposal, deforestation, and mining activities. It reduces soil fertility, contaminates food crops, and disrupts ecosystems.
