Groundwater Pollution: What Are The Main Culprits?

Groundwater pollution is a serious issue that can have a significant impact on public health. It can be caused by a variety of factors, including the overuse of pesticides and fertilisers, sewage disposal, and untreated waste discharge. Human activities such as agriculture and industry can also put the integrity of aquifers at risk, which may collapse if they are drained. This could reduce the amount of water available for human use. Other causes of groundwater pollution include on-site sanitation systems, such as pit latrines and septic tanks, which can contaminate groundwater with pathogens and nitrate.

Untreated waste discharge

One of the main ways that untreated waste can pollute groundwater is through the use of on-site sanitation systems such as pit latrines and septic tanks. If these systems are not properly maintained or if the local hydrogeological conditions are ignored, liquids can infiltrate the ground and contaminate the groundwater with pathogens and nitrates. This can lead to the spread of diseases such as typhoid, cholera and diarrhoea, which are transmitted through the faecal-oral route.

Another way that untreated waste can pollute groundwater is through the use of pesticides and fertilisers in agriculture. When these chemicals are overused or improperly disposed of, they can seep into the ground and contaminate the groundwater. This can be particularly harmful as groundwater constitutes an important part of the world's available freshwater, and if it is contaminated, it can put the health of those who rely on it at risk.

Improperly placed wells can also contribute to groundwater pollution from untreated waste. If wells are not properly constructed or maintained, they can allow waste to infiltrate the groundwater, leading to contamination with pathogens carried in faeces and urine. This can be particularly dangerous as certain pathogens, such as bacteria, viruses and protozoa, can survive in the groundwater and cause diseases such as skin lesions and dermatitis.

To prevent groundwater pollution from untreated waste discharge, it is important to have proper sanitation measures in place and to ensure that waste is treated properly before it is discharged into the environment. This includes the proper maintenance of on-site sanitation systems and the responsible use and disposal of pesticides and fertilisers. By taking these precautions, we can help to protect the integrity of our groundwater and ensure that it remains a safe and reliable source of drinking water for all.

Pathogens from sanitation systems

Groundwater pollution can be caused by pathogens from sanitation systems. This can occur when liquids infiltrate the ground from on-site sanitation systems such as pit latrines and septic tanks. The population density and hydrogeological conditions will determine the extent of this pollution. If local hydrogeological conditions are ignored, simple on-site sanitation systems can cause significant public health risks via contaminated groundwater. Liquids leach from the pit and pass through the unsaturated soil zone (which is not completely filled with water).

The lack of proper sanitation measures, as well as improperly placed wells, can also lead to drinking water contaminated with pathogens carried in faeces and urine. Such faecal-oral transmitted diseases include typhoid, cholera and diarrhoea. Of the four pathogen types that are present in faeces (bacteria, viruses, protozoa, and helminths or helminth eggs), the first three can be commonly found in polluted groundwater, whereas the relatively large helminth eggs are usually filtered out by the soil matrix.

Deep, confined aquifers are usually considered the safest source of drinking water with respect to pathogens. However, pathogens from treated or untreated wastewater can contaminate certain, especially shallow, aquifers. This can lead to diseases such as skin lesions, bloody diarrhoea and dermatitis.

Human activities carried out on the surface, such as sewage disposal, can also be among the main sources of contamination and pollution of groundwater.

Human activities, such as agriculture and industry

Human activities carried out on the surface, such as sewage disposal and the overuse of pesticides and fertilizers, including animal manure, are among the main sources of contamination and pollution of groundwater. The lack of proper sanitation measures, as well as improperly placed wells, can lead to drinking water contaminated with pathogens carried in faeces and urine. Such faecal-oral transmitted diseases include typhoid, cholera and diarrhoea.

Groundwater pollution with pathogens and nitrate can also occur from liquids infiltrating into the ground from on-site sanitation systems such as pit latrines and septic tanks, depending on the population density and the hydrogeological conditions. If the local hydrogeological conditions are ignored, simple on-site sanitation infrastructures such as pit latrines can cause significant public health risks via contaminated groundwater. Liquids leach from the pit and pass the unsaturated soil zone (which is not completely filled with water).

VOC pollutants, including aromatic hydrocarbons

Groundwater pollution can be caused by untreated waste discharge, leading to diseases like skin lesions, bloody diarrhoea and dermatitis. It can also be caused by the overuse of pesticides and fertilisers, including animal manure, and sewage disposal.

BTEX compounds are a concern due to their toxicity and potential carcinogenicity. They are often found in industrial settings, such as oil refineries and chemical plants, and can contaminate groundwater through leaks or spills. Benzene, for example, is a known human carcinogen and has been linked to leukaemia and other blood disorders.

Chlorinated solvents, such as tetrachloroethylene, are also of concern due to their persistence in the environment and potential health effects. They are commonly used in industrial processes such as dry cleaning, metal degreasing and solvent manufacturing. If released into the environment, they can infiltrate the groundwater and persist for long periods due to their resistance to biodegradation.

The presence of VOC pollutants in groundwater is a significant issue as it can lead to the contamination of drinking water sources, posing risks to human health. These pollutants can also impact the environment, affecting aquatic life and the overall ecosystem. Therefore, it is crucial to address and mitigate the sources of VOC pollution to protect both human and environmental well-being.

Lack of proper sanitation measures

The lack of proper sanitation measures can lead to contaminated drinking water, which can cause serious health issues. Groundwater pollution can be caused by untreated waste discharge, leading to diseases such as skin lesions, bloody diarrhoea, and dermatitis. Pathogens carried in faeces and urine can contaminate water sources, spreading diseases such as typhoid, cholera, and diarrhoea. This is a significant public health risk, especially in areas with high population density and inadequate sanitation infrastructure.

On-site sanitation systems, such as pit latrines and septic tanks, can contribute to groundwater pollution if not properly managed. Liquids from these systems can infiltrate the ground and contaminate water sources, depending on hydrogeological conditions. The fate and transport of pathogens in the environment are complex and not yet fully understood, making it challenging to control and prevent groundwater pollution effectively.

Human activities, such as sewage disposal, the overuse of pesticides and fertilisers, and the use of animal manure, are also major contributors to groundwater pollution. The intensive use of groundwater for agriculture and industry can further exacerbate the problem, as it may exceed the rate at which aquifers can refill. This not only risks the integrity of the aquifers but also the global amount of water available for human use.

Deep, confined aquifers are generally considered safer sources of drinking water regarding pathogens. However, even these sources can be contaminated by pathogens from treated or untreated wastewater, especially in shallow aquifers. Proper sanitation measures are crucial to preventing groundwater pollution and protecting public health.

Additionally, primary VOC pollutants found in groundwater include aromatic hydrocarbons such as BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) and chlorinated solvents like tetrachloroethylene. These pollutants can have detrimental effects on both human health and the environment.

Frequently asked questions