Groundwater is the water resource which is stored under the surface. About 30% of the world’s fresh water comes from groundwater. However, about 97% of the recoverable water comes from groundwater. Less than 1% percent of the water in the river reservoir.The remaining 69% of water is stored in the form of glacier. We all know that, water is a very important element of the environment and living organisms, especially groundwater. In Bangladesh, most of the villagers depend on ground water for drinking water. In urban areas, water supply is mainly dependent on groundwater. In the capital Dhaka, more than 87% of the total water supply comes from underground water; the remaining part comes from surface water treatment. Now-a-days, Groundwater is also widely used for irrigation.
According to the estimates of 1995, 72% of the total irrigation water is extracted from the ground. According to a survey of the Planning Agency of Bangladesh, underground water reserves in Bangladesh are 2,575 million cubic meters, of which 168.6 million cubic meters are not extractable. The remaining reserves of 90 million cubic meters can be used for household and industrial production and a maximum of 1,281 million cubic meters for agriculture. According to the World Health Organization report, in the developing countries, 2.5 million people die from water-borne diseases every year. It is also said that there is a shortage of 10 million liters of pure water every day in the country. Every day in the capital of Bangladesh, 220 to 300 million liters of water is needed. In the last three decades, about 50 crore taka has been spent on groundwater, but pure water has not been confirmed.
At present, about 30 million people are suffering from water crisis across the country every year. As the demand of drinking water is increasing every day in the country, it is not possible to completely meet that demand from ground water. Groundwater levels are going down every year due to unplanned water extract. As the water level goes down, underground water are coming into the tube well with harmful heavy metals and contaminants. As a result of drinking this water people are suffering from various diseases.
Generally, water is extracted through shallow tube wells in our village. But at present, due to extract extra water, it is not available at a time of the year, especially during the dry season. With this added new groundwater pollution.Because the surface contamination goes down into the soil and mixes with water.Which rises again through the tube well. That water enters the human body, reduces immunity and helps to create new diseases. Now-a-days, arsenic is causing broad contamination in groundwater. This is one of the biggest problems to the development of groundwater. Prior to the discovery of ionic contamination, people in the village were largely dependent on groundwater. At present, this amount has decreased substantially.
Currently, arsenic pollution in the country is in terrible shape. Arsenic is stored at a special level of the soil and is lifted through the tap water. Over the past few decades, the use of chemical fertilizers and pesticides in agricultural production has increased widely as it is polluting rivers, rivers, canals, bills, sea water and even groundwater.The use of chemical fertilizers and pesticides in agricultural land is one of the major causes of arsenic pollution. The arsenopyrite, which contains a special layer of soil, is mixed with water due to the excess water extraction.Arsenic pollution is being created which is taking terrible shape over time. Moreover, salinity is increasing day by day in the ground water. Coastal areas are more prone to salinity. Experts say the saline areas in the southern part of the country are increasing gradually. It has also spread to western areas. The adverse effects of salt create on agricultural management and crop composition.As a result, crop production is gradually decreasing. Besides, the water is also inaccessible due to its salinity in the coastal areas of the country. During natural disasters, one third of these areas are at risk of contaminating household water which is a serious threat to public life.
Apart from arsenic, high levels of iron, high salinity in coastal areas, excessive intensity of manganese etc. are also destroyed water quality. Sewage coliform is also a major problem, especially for shallow groundwater. When the groundwater surface falls below 6 meters, water does not rise in the tube well. Then different technologies have to take. Continued degradation of groundwater also increases the cost of digging wells. Another damaging aspect of groundwater depletion is land debris. The situation is suspected in Dhaka City.
However, despite the forecasts, no signs of land degradation have been observed in Bangladesh due to the underground water withdrawal. Due to the factories and municipal waste disposal sites, the quality of groundwater is also gradually deteriorating in big cities like Dhaka. This is a risk to global warming and groundwater to the coastal areas of Bangladesh.Various industries are growing in the country. Construction of various vehicles in petrochemical industry, polyethylene and plastics industry, energy industry, mineral oil refining industry, small and medium electrical and engineering industries in large quantities of pollutants such as ammonium chloride, cyanide and various metals such as zinc, mercury, lead water. According to the IEDCR and CDC program sources of the Health Department, water is increasing the risk of natural imbalance. Due to the rapid population growth and urbanization, residential areas, hats, bazaars, roads, factories, sewage centers are being constructed.From sources like oil tankers, toxins such as metals, lead, mercury, zinc and chromium are constantly falling into the water. Moreover construction and printing presses also responsible for water pollution. On the other hand, when people in rural areas are aware of surface water contamination, they are suffering from arsenic when they start using tap water.
In addition, the surface water is polluted due to excess pesticide use. These pesticides contain nitrogen, potassium and phosphorus. Using excess pesticides, it poisons the water inside the soil. The level of water contamination within the urban area has gone to critical levels.
Chemicals, heavy metals, rust, lead, cadmium, mixed with water, cannot be eliminated by just boiling. It is important to identify the substance in the water. After that, the purification system has to be taken separately. Separate measures have to be taken to purify the water. Proper and scientific management is needed to reduce the salinity level of water in coastal areas and make it safe and suitable for drinking. But the people of the coastal region are always underprivileged. So the people of that region are now facing a life-threatening crisis for water. The development of more effective strategies to disinfect arsenic in tube well water has become urgent.It is mandatory to set up a refinery or effluent treatment plant (ETP) with each factory. The use of excessive pesticides in agricultural land should be minimized. We should manage waste and wastewater properly. The government should take effective steps to protect groundwater and develop a pollution prevention plan. At the same time, everyone should be aware that there is no garbage dump. Everyone should be encouraged to put waste in a certain place.
Misuse of water should be prevent, use only as much as necessary. Keep in mind that, underground water is limited. In particular, dependence on groundwater should be minimized in agriculture. Rainwater harvesting should be taken into account so that it can be used in the future. Only then, we can easily meet water demand and prevent underground water pollution.
The author of this article is a student of Department of Environmental Science & Engineering, Jatiya Kabi Kazi Nazrul Islam University Trishal, Mymensingh.