Pathogenic Bacteria: Pollutants Or Not?

Pathogenic bacteria are a significant cause for concern when it comes to water pollution. They are often associated with waterborne diseases, such as gastrointestinal illnesses, and can be transmitted through various sources, including sewage, wastewater, and agricultural runoff. While non-pathogenic bacteria are an essential part of the aquatic ecosystem, their pathogenic counterparts can cause harm to a variety of organisms, including humans. The presence of pathogenic bacteria in water resources is largely due to human activities, and the contamination of groundwater and surface water poses a serious risk to public health. The understanding of pathogen transport and the development of control measures are crucial to mitigate the impact of pathogenic bacteria as pollutants.

Pathogenic bacteria in water resources

One of the primary sources of pathogenic bacteria in water is the discharge of wastewater into freshwater and coastal seawater. This wastewater often contains human or animal feces, which can harbor harmful bacteria. The ingestion of contaminated water or consumption of food exposed to such water can lead to microbial diarrheal diseases, gastrointestinal illnesses, cholera, typhoid fever, and bacillary dysentery. Children under five, especially in Asian and African countries, are highly vulnerable to these waterborne microbial diseases.

The transport of pathogens from surface water to groundwater further exacerbates the problem. According to Jin and Flury (2002), 70% of waterborne microbial illness outbreaks in the United States are linked to groundwater contamination. Factors such as soil type, solution chemistry, temperature, and virus properties influence the survival and transport of pathogens through porous soil matrices. Additionally, the application of manure in agricultural fields can introduce bacteria into water resources, as seen in studies by Jamieson et al. (2002) and Unc and Goss (2004).

To address these concerns, there is a growing interest in controlling waterborne pathogens. Efforts are being made to develop comprehensive studies that unify knowledge from multiple fields to tackle the problem holistically. Public health officials and scientists rely on established exposure limits to assess pathogen levels in water resources and protect human health. Additionally, technological and policy options are being evaluated to reduce and control health risks associated with wastewater reuse in agriculture and to ensure access to clean and safe drinking water.

Sources of pathogenic bacteria

Pathogenic bacteria are bacteria that can cause diseases in humans. Most bacterial species are harmless, and many are beneficial, but a small number can cause infectious diseases. These bacteria can enter the body through the skin, sexual activity, or through compromised immune function.

Waterborne pathogenic bacteria are a significant cause of mortality and morbidity in many developing countries. The main source of pathogenic bacteria in rivers is sewage, which can enter rivers during heavy rain or flooding, especially in areas with poor sanitation and incomplete wastewater treatment. This problem is particularly acute in megacities with more than 10 million inhabitants. In addition, the breakdown of sewage plants due to flooding or earthquakes can also release pathogenic bacteria into water sources.

Groundwater can also be contaminated by pathogenic bacteria through seepage and percolation of contaminated water from the vadose zone, which is influenced by the application of manure in agricultural land. The presence of straw and coarse organic matter can further facilitate the persistence of bacteria in the soil.

Pathogenic bacteria can also be transmitted through human excrement, as evidenced by the book "The Humanure Handbook: A Guide to Composting Human Manure." Improper handling and disposal of waste within healthcare facilities have also been recognized as sources of avoidable infections.

Furthermore, pathogenic bacteria can be introduced into the body through the skin or mucous membranes. Some species of Streptococcus and Staphylococcus, which are typically part of the normal skin microbiota, can potentially cause skin infections, sepsis, pneumonia, and meningitis. These infections can become severe and lead to a systemic inflammatory response, resulting in massive vasodilation, shock, and even death.

Health risks of pathogenic bacteria

Pathogenic bacteria are a type of pathogen, which are microorganisms that cause disease. While most bacteria are harmless, pathogenic bacteria can make you sick and cause infections that require treatment. They can reproduce quickly in your body and release poisons (toxins) that can cause illness and tissue damage.

Some examples of harmful bacteria include Streptococcus, which causes strep throat, and Staphylococcus, which causes staph infections. Escherichia coli (E. coli) is another pathogenic bacterium that can cause blood poisoning (septicemia). These bacteria are often transmitted through water and improper sanitation, causing gastrointestinal symptoms such as diarrhoea, vomiting, and stomach cramps. They can also lead to malnutrition and affect other organs.

Waterborne diseases caused by pathogenic bacteria are a significant concern worldwide, with 70% of microbial illness outbreaks in the United States linked to groundwater. Contamination of groundwater can occur through various means, including seepage from contaminated surface water, septic tanks, and agricultural activities. This poses serious risks to human health, especially in areas with shallow aquifers.

Healthcare providers typically treat bacterial infections with antibiotics. However, the overuse of antibiotics has led to the emergence of antibiotic-resistant bacteria, making some infections challenging to treat. Additionally, a compromised immune system can increase the body's susceptibility to bacterial infections.

To reduce the risk of pathogenic bacterial infections, it is essential to practice good sanitation and hygiene, ensure safe water consumption, and maintain proper waste management practices, especially in healthcare settings.

Waterborne diseases caused by pathogenic bacteria

One example of waterborne disease caused by pathogenic bacteria is cholera. Cholera is commonly found in humanitarian emergencies or marginalized villages with poor sanitation and poverty. It is spread through contaminated water, causing severe dehydration and diarrhoea. While most people will not develop life-threatening symptoms, cholera can be fatal within days or even hours of exposure.

Another waterborne disease is typhoid fever, which is well-known in developing nations with poor sanitation and unsafe water. It is spread through contaminated food and water and is highly contagious. Typhoid fever can cause dangerous pathogens that lead to severe health issues.

Hepatitis A is another liver infection caused by consuming contaminated food and water or by close contact with an infected individual. This disease is common among travellers to developing countries or those working in areas with poor sanitation and hygiene management.

Pathogenic bacteria can contaminate water resources through various pathways. For instance, groundwater can be contaminated by seepage and percolation of contaminated water from the vadose zone, which includes agricultural land where manure is applied. The presence of manure influences pathogen transport and the survival of bacteria in the soil. Additionally, the transport of pathogens from surface water to groundwater increases the vulnerability of groundwater to contamination.

The impact of waterborne diseases caused by pathogenic bacteria is significant, particularly in communities with limited access to safe and clean water. It is essential to address these issues through improved sanitation, hygiene practices, and the provision of clean water sources to prevent the spread of waterborne illnesses and reduce their impact on global health.

Controlling pathogenic bacteria in water

Pathogenic bacteria are a type of pollutant that can cause waterborne diseases, such as gastrointestinal illnesses like diarrhoea, vomiting, and stomach cramps. They are a major water quality concern worldwide, and their presence in water resources poses serious risks to human health.

Sources of Pathogenic Bacteria in Water

Pathogenic bacteria can enter water sources through various means, including:

• Wastewater discharges: The release of untreated or partially treated wastewater into freshwater and coastal seawater introduces fecal bacteria and pathogens into water sources.
• Agricultural activities: The use of manure in agriculture can contaminate groundwater, especially in areas with shallow aquifers.
• Natural disasters: Precipitation events, such as floods, can increase the risk of groundwater contamination by washing contaminated surface water into groundwater sources.

To control the presence of pathogenic bacteria in water, several methods and technologies can be employed:

• Wastewater treatment: Properly treating wastewater before discharge can effectively remove bacterial, viral, and protozoan pathogens. Technologies such as multicell stabilization ponds are low-cost and easy to operate, making them suitable for developing countries.
• Sanitation practices: Improving sanitation practices, especially in developing countries, can reduce the transmission of waterborne diseases. This includes the safe disposal of human and animal waste to prevent the spread of fecal bacteria.
• Water reuse practices: Reusing water from diverse sources (greywater, wastewater, stormwater) can help increase water efficiency, but it requires proper treatment to control bacterial growth and prevent health risks. Technologies like BAMBi, GAC, and electrolysis show promise in controlling bacterial growth during water storage for reuse.
• Indicator organisms: Using indicator organisms to assess water quality can help identify the presence of pathogenic bacteria. However, there are challenges associated with using these indicators, and ongoing research aims to address these limitations.
• Iron control: Monitoring and controlling the introduction of blood as a source of iron can limit the growth of certain pathogens, such as S. typhimurium.
• Drinking water standards: Implementing microbiological control of drinking water can help ensure safe drinking water for all, which is a significant challenge in the 21st century.

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