Groundwater Contamination: A Man-Made Disaster
In February, the IPCC Working Group-II released the second part of the sixth assessment report, ‘Climate Change 2022: Impacts, Adaption, and Vulnerability’. The key findings concerning groundwater scarcity are over-extraction of water for drinking and irrigation purposes, greater urbanization, climate change, and many more. The pressure built on the groundwater aquifers due to global warming is worsening with man-made mishaps. Today the groundwater is poisoned by artificial products containing chemicals used by mankind. Special attention must be given to protecting and preserving the groundwater as it remains a lifeline to numerous living organisms.
About 71 percent of Earth’s surface is covered with water. The water on this planet is continuously replenishing through an effective hydrological cycle. Although there is an abundance of water, only 0.3 percent of this humungous amount is usable by humans. Within this small share, much of it remains unattainable. Groundwater accounts for 0.61 percent of the total water limit on the Earth [1]. Groundwater is underground water in cracks and gaps in soil, sand, and rock. The water gets trapped beneath the surface after precipitation when it continuously seeps to form a saturated layer. It can be easily extracted using wells, tunnels, or a pumping system. It plays a significant role in human lives by providing water for both residential and industrial purposes. The following are advantages of groundwater over other water resources [2],
a) It can be stored for a longer period as it is absorbed by the soil, therefore, reducing the rate of evaporation.
b) It helps the soil retain moisture which further improves vegetation.
c) It maintains the water levels of the wells.
d) It has nearly no impurities which make the quality superior.
e) It is an important source to rejuvenate the surface water bodies like lakes and rivers when precipitation is minimal.
f) It supports the irrigational needs of the agricultural communities.
g) It is relatively protected by human and animal waste, however, that seems to be changing with an increasing rate of waste disbursal on the surface.
Causes of the Contamination
Groundwater is highly vulnerable to pollution. Anthropogenic activities are solely responsible for increased contamination of groundwater. There are two categories of origination of the contaminants: point sources and non-point sources [3]. Septic tanks, municipal landfills, livestock wastes, sewer lines leaks, fly ash from coal-fired plants, sludge disposed from petroleum factories, spills of industrial chemicals from factories, graveyards, gasoline storage tank leakage, and others are included under point sources. These sources have direct involvement of humans. Containers storing oil and chemicals if not maintained judiciously then liquids can easily penetrate into groundwater. Similarly, the breakdown of the on-site waste disposal systems used by households, offices, and industrial buildings can result in the gradual degradation of groundwater and introduce bacteria contaminating the entire water sources of an area. It is highly crucial that before any industrial setup or developmental project is passed, thorough studies are undertaken to analyze the characteristics of the waste generated from them, its volume, composition, the concentration of various constituents, rate of waste disposal, and so on. Therefore, countermeasures can be chalked out to decrease the dispersal of the toxins in the groundwater.
Non-point sources do not have a single origination point but are distributed sources and have a cumulative effect. These include fertilizers and pesticides used on agricultural lands and natural contaminants in rainwater, snow, and dry atmospheric deposition on the surface. Human-induced activity to use abundant pesticides and fertilizers with the aim to expand production rate has a long-term impact on the groundwater quality [4]. When sprayed in green fields and croplands, it gets accumulated and migrates to the water table. Further, it reaches the water pumped from wells used for drinking and other daily chores. This leads to the formation of a vicious cycle wherein the chemicals released by us end up in our homes. Another major non-point source is a natural source including substances present in soils and rocks that can get dissolved through geochemical cycles over a period of time. Decaying material in the soil, sulfates, iron, fluorides, manganese, chlorides, radionuclides, and arsenic can seep into groundwater as the particles move with the rate of precipitation.
Dangers of the Contamination
Contaminated groundwater has harmful effects not only on the environment but leads to grave health issues. When a hazardous substance percolates through the soil, it can be caught in the suction force from a pumping well. These substances are drawn into the wells and enter the public water supply. Moreover, it is a costly and time-consuming task to clean this tainted water, even after all the efforts the water does not get completely free from toxins. The poisonous water contains malignant chemicals and viruses causing irreversible liver and kidney failure, severe gastrointestinal effects, neuromuscular damage, cancer, bone disorder, delay in physiological growth of babies, and so on. Therefore, contaminated groundwater has many detrimental health effects.
Extreme levels of contamination can alter the entire ecosystem. It destroys the existing aquatic life as the quality of water worsens. It loses all essential nutrients resulting in the death of fauna inside water which in turn has a catastrophic impact on the marine food supply. Any animal or plant coming in close contact with contaminated water will carry the negative effect forward. Hence, this is an indirect channel of how contaminants are entering our life cycle.
Lastly, groundwater contamination depreciates the economic growth of a region as no plant, human, or animal life is able to sustain it. The earlier populated area begins to turn barren and the economy dies. Industries backed by such toxic water to undertake their production also suffer and they are forced to import water from safer areas, however, it remains a costly affair.
Current Crisis in India
India is the largest groundwater user in the entire world. It amounts to approximately 230 cubic kilometers of groundwater per year i.e. over a quarter of the global groundwater availability. It remains one of the critical water resources for the country. More than 85 percent of the groundwater is used for drinking purposes and more than 60 percent is invested in agriculture supporting irrigational needs [5].
The water availability in India is highly questionable, further, contamination is adding tremendous stress. Reduction in groundwater levels is further leading to a higher concentration of contaminants in water. Around three-quarters of India's rural population is dependent on groundwater to fulfill their needs, however, they have to struggle with quantity and quality issues every day. At least ten states in the country have reported fluoride and arsenic contamination in the groundwater, among them Delhi, Gujarat, West Bengal, Karnataka, Maharashtra, Punjab, Rajasthan, Telangana, Chhattisgarh, and Haryana are the hotspots [6]. However, the problem remains invisible because surface water pollution receives the utmost attention. Groundwater is a critical water supply in a country wherein monsoon rains are unpredictable and the majority of the agricultural needs are still reliant on rainwater. Therefore, India's food distribution is positively supported by the availability of clean groundwater and the success rate is higher as farming communities can self-regulate the usage of this water.
It is important that we learn how vital groundwater is for humanity. It not only satisfies drinking needs but can aid in economic growth. Climate change has become a major concern destroying our natural resources, and also has an impact on groundwater. Increased volatility in the amount of precipitation leads to an extended period of drought, further, drying up underground aquifers. Groundwater is unable to act as a buffer anymore in circumstances of lack of surface water. Hence, when there is already an undue pressure on groundwater sources due to the global climate change then man-made actions must discontinue contaminating groundwater by proper management of hazardous wastes.
References:
[1]https://www.ngwa.org/what-is-groundwater/About-groundwater/information-on-earths-water
[2]https://deepoceanfacts.com/advantages-and-disadvantages-of-groundwater-use-in-daily-life
[3]https://www.canada.ca/en/environment-climate-change/services/water-overview/pollution-causes-effects/groundwater-contamination.html
[4]https://www.usgs.gov/special-topics/water-science-school/science/contamination-groundwater#overview
[5]https://www.worldbank.org/en/news/feature/2012/03/06/india-groundwater-critical-diminishing#:~:text=Key%20Issues,India%20is%20the%20largest%20user%20of%20groundwater%20in%20the%20world,supplies%20are%20dependent%20on%20groundwater.
[6]https://www.hindustantimes.com/india-news/not-just-scarcity-groundwater-contamination-is-india-s-hidden-crisis/story-bBiwL1eyJJeMgFQcX4Cn7K.html
Pic Courtsey-Bradford Zak at unsplash.com
(The views expressed are those of the author and do not represent views of CESCUBE.)
