Abstract

Pakistan's drinking water quality is deteriorating day by day due to rapid industrialization and an alarming rise in population. This review summarizes the results of several research studies that were conducted to assess the drinking water quality in different parts of Pakistan. It also considers the physicochemical and pathogenic microorganisms. Pakistan's entire population has access to safe drinking waters. Due to a lack of safe and clean drinking water, 80% of Pakistan's population has to drink unsafe water. 

Sewerage (fecal), which is frequently discharged into the drinking water supply, is the main source of contamination. The secondary source of contamination is the discharge of toxic chemicals, such as pesticides and fertilizers, from industrial effluents into water bodies. 

Waterborne diseases are caused by human activities, which account for around 80% of all deaths and 33% of all illnesses. This review focuses on the quality of drinking water, contaminants, sanitation conditions, and health effects of unsafe drinking water. To improve the hygiene of water supply in Pakistan, we must take precautionary measures and use treatment technologies.

Pakistanis live in southern Asia and border India, Afghanistan, and China. Mountains of Himalayan and Karakorum can be found in the east of Pakistan. The Hindukush ranges can be found in the north. There are also hill regions (upto 4700m) in the northwest, as well as the Baluchistan plateau in the upper Baluchistan. Most of Pakistan's climate is semi-arid to arid, with different levels of rainfall in different parts. The main river in Pakistan is Indus. It flows from Karakorum to the south, and then falls into the Arabian Sea. 

Pakistan's economy is dominated by agriculture farming. 27% of total land is currently under cultivation. The main crops are wheat and maize, rice, sugarcane, cotton, and rice. Pesticides and fertilizers are used to improve the crop yield in order to meet the growing population's needs. Major cities are home to most industries, including textile, pesticide, fertilizer, and other industries.

Nature has provided enough water resources for Pakistan. Water resources have been under tremendous stress due to rapid population growth, industrialization, and urbanization. Water plays a crucial role in all aspects of our lives, including development and growth. Water plays a significant role in every aspect of our lives. 

Technological advancements have made it possible for drinking water to contain impurities of various types, including those that are physical, biological, or chemical in nature. The most harmful impurity is one of biological nature. This can cause serious health problems and even death. Diverse impurities, including nutrients and microorganisms, can be transported from one location to the next. Water pollution is caused by microorganisms, toxic chemicals and industrial wastes that are either in direct contact with water bodies or leach into groundwater or freshwater resources. It is possible to detect coliform bacteria in human and animal feces. Rainy season is the best time for bacteria growth and dispersion. This is due to water body drainage, i.e. rivers, lakes and streams. Waterborne diseases are spread by poor treatment facilities. Pakistan's drinking water sanitation system is connected to the drainage lines, which can lead to leakages and intermixing, leading to deterioration in water quality.

Ground water supplies are the primary source of water in most cities in Pakistan. They contain many pathogens, including bacterial and viral agents, that cause 2.5 million deaths each year from endemic diarrheal diseases.

Water pollution refers to the physical process of water contamination in water resources, such as groundwater, lakes, and rivers, due to human activities. Waterborne diseases can be spread by the use of low-quality water. Poor drinking water quality is responsible for approximately 50% of all deaths and half of all diseases in Pakistan. 

More than 80% of Khyber Pakhtunkhwa's population has access to clean drinking water from both ground and surface sources. KP's surface water sources are safe and suitable for drinking. However, the ground water in the south is darkened. Deepness is another source of clean water. However, the central part of KP has a high level of ground water availability. This is pumped out by tube wells to be used for routine purposes. The north of KP is dominated by surface water resources and springs. Poor treatment of deteriorated water, and an outdated sanitation system in urban areas have led to a very low quality and quantity of drinking water.

Water availability

Pakistan has ample water resources, both surface and ground. Anthropogenic activities like industrialization, increased population, and poor utilization reduce the quantity and damage quality. Jamshed Iqbal Cheema (Chairman, Pakistan Agriculture Scientists Association) states that the per capita water supply in Pakistan in independence was 5,600 cubic metres. This has decreased by more than 406 percent since 1951 when it was 5,260 cubic meters and dropped to 1,038 cubic metres in 2010. If this status quo is maintained, then the per capita water availability in Pakistan by 2020 will be 877 cubic metres per annum. 

It will decrease further to 660 cubic meters by 2025, and to alarming levels of 575 cubic feet by 2050. Aquifers provide 70% of the water needed for drinking. Ground water quality has declined due to overpumping and the addition of fresh water. Ground water quality in Pakistan can be described as saline away from main rivers, and fresh water close to main rivers. The water source quality, level and efficiency of treatment, as well as the condition of the water supply lines, all affect the quality of drinking water. 

People in Pakistan have to drink this water because it is available in areas without a fresh water source. Water contamination by microbes is the biggest problem. Urban water distribution does not meet WHO standards. Microbial contamination occurs due to intermixing of drinking water supply lines and sewer lines. Most of Pakistan's rural areas have surface water that is treated with slow sand filtering and chlorination. Most rural areas lack pretreatment facilities for water filtration. 

This is due to poor water quality and microbial contamination. Surface runoff and flooding can cause damage to hand pumps and wells. Water pollution refers to the contamination of water by wastes from domestic and industrial industries. The harmful effects of using such water for commercial purposes can have adverse consequences on the environment and public health. The growth of urban areas and industrialization have placed enormous stress on water resources. Wastewater is discharged into natural water resources, which decreases the quality of ground and surface water.

Conclusion

The review covered the Pakistani studies on water quality and contamination. It found that sewerage water (fecals) was the most prevalent and primary contaminant in Pakistan due to poor sanitation and the sewerage system. Chemical pollution is the second source of contamination. This can be caused by chemical pollutants, such as pesticides and textile dyes, industrial effluents, fertilizers, nitrogenous fertilizers or arsenic. It is important to inspect and maintain existing treatment plants regularly. The Government of Pakistan has started installing drinking water filters throughout Pakistan. These results have highlighted the importance of sewerage contamination in drinking water and raised concerns about health and environmental issues.