Understanding Biological Pollution: Its Root Causes And Sources

Biological pollution, or biopollution, is one of the main types of air pollution and comes from living organisms. It is caused by biological contaminants, which include bacteria, moulds, mildew, viruses, animal dander, cat saliva, house dust, mites, cockroaches, and pollen. These contaminants can cause allergic reactions, trigger asthma, and spread infectious diseases. Sources of these pollutants include plants, people, animals, soil, and household pets. Contaminated central air handling systems and humidifiers can also become breeding grounds for biological contaminants, distributing them throughout homes and buildings.

Characteristics and Values of the Causes of Biological Pollution

Bacteria, viruses, and protozoa

Water filtration and purification techniques are employed to reduce the concentration of these microorganisms and other dangerous biological pollutants in contaminated water. However, complete disinfection and removal of all bacteria, viruses, and protozoa are not always feasible. Water authorities like the WHO and the EPA have established minimum allowed microbial limits for clean water.

Sources of water contamination by bacteria, viruses, and protozoa include human and animal waste, agricultural activities, and septic tanks. These pathogens can be transported from surface water to groundwater, increasing the vulnerability of water resources. Progressive globalization, intensive agriculture, climate change, and changes in microorganism properties have also been identified as causes of new microbial threats in water systems.

Additionally, bacteria, viruses, and protozoa can contribute to indoor air biological pollution. They can be carried by people, animals, and soil, leading to the spread of infectious illnesses. Proper ventilation, humidity control, and cleaning are essential to minimize the growth and spread of these biological contaminants in indoor environments.

Water systems and wastewater

Point Source Pollution

Point source pollution originates from a single, identifiable location, such as a manufacturer, oil refinery, or wastewater treatment facility. It also includes contamination from leaking septic systems, chemical and oil spills, and illegal dumping. According to the EPA, sewage treatment systems in the United States release more than 850 billion gallons of untreated wastewater annually, contributing to biological pollution in water systems.

Nonpoint Source Pollution

Nonpoint source pollution, the leading cause of water pollution in the US, is more challenging to regulate as it originates from diffuse sources. This includes agricultural runoff, stormwater runoff, and debris blown into waterways from land. During heavy rainfall, stormwater can exceed sewer capacity, causing untreated sewage to spill directly into surface waters, leading to biological pollution.

Industrial Wastewater

Industrial activities generate large volumes of wastewater containing harmful pollutants such as heavy metals and toxic chemicals, and arsenic, cadmium, and chromium compounds. The discharge of untreated or partially treated industrial wastewater into water bodies adversely affects aquatic ecosystems and human health.

Agricultural Activities

Agricultural practices contribute to biological pollution in water systems through the use of pesticides, nitrogen fertilizers, and organic farm wastes. These contaminants can enter water systems through agricultural runoff, polluting freshwater sources and affecting aquatic life.

Sewage and Domestic Wastewater

Inadequate sewage treatment and the discharge of untreated domestic wastewater, including greywater (from kitchens, laundry, and washrooms) and blackwater (human excreta), can lead to the spread of disease-causing pathogens in water systems. This is a significant issue in underdeveloped and developing countries, where sanitation and wastewater treatment facilities are lacking.

Exotic Species Introduction

Increased economic activity and global trade have resulted in the introduction of invasive marine species through ballast water and hull fouling. These non-native species can have detrimental effects on indigenous communities and the ecological balance of water systems.

Addressing biological pollution in water systems and wastewater requires a combination of improved wastewater treatment technologies, stricter regulations, and sustainable practices in various sectors, including industry and agriculture.

Air quality and ventilation

Biological pollutants in the air include bacteria, viruses, pollen, animal dander, and mould, among others. These contaminants can trigger allergic reactions, such as allergic rhinitis and asthma, and can also cause infectious illnesses like influenza, measles, and chickenpox. Mould and mildew, in particular, can release toxins that lead to health problems, including coughing, shortness of breath, and fever.

To improve air quality and reduce the impact of biological pollutants, proper ventilation is essential. Opening windows at night, using exhaust fans in kitchens and bathrooms, and ventilating attics and crawl spaces can help prevent the buildup of contaminants. Additionally, maintaining relative humidity levels between 30-50% in indoor spaces can inhibit the growth of mould, mildew, and other biological contaminants.

It is worth noting that some individuals may be more susceptible to the effects of biological pollutants, including children, the elderly, and people with pre-existing breathing problems, allergies, or lung diseases. For those with allergies or asthma, taking extra precautions, such as using air purifiers, allergen-proof mattress covers, and regular hot water washing of bedding, can help reduce exposure to allergens.

Overall, by understanding the sources and impacts of biological pollutants, we can implement effective ventilation and humidity control strategies to improve air quality and create healthier living and working environments.

Household pets and pests

Household Pets

Pets, such as cats, are a source of animal dander and saliva, which are biological contaminants. Pet dander, or dead skin cells, can trigger allergic reactions and asthma in susceptible individuals. Additionally, pet saliva can contain bacteria and viruses that can be transmitted to humans, potentially causing illnesses.

Household Pests

Pests like cockroaches, rats, and mice are common sources of biological pollution in indoor environments. They contribute to indoor air quality issues by introducing allergens and disease-causing agents. For example, the protein in urine from rats and mice is a potent allergen that can become airborne when it dries. Pests can also carry bacteria, viruses, and other microorganisms that can contaminate surfaces and spread illnesses.

In addition to the direct health impacts, pests can also affect indoor air quality by attracting other pests and creating favourable conditions for biological contaminants to thrive. For instance, pest droppings and body parts can serve as food sources for other insects or create breeding grounds for mould and bacteria.

Preventative Measures

To minimise the impact of household pets and pests on indoor biological pollution, several preventative measures can be taken:

• Regular cleaning and vacuuming can help reduce the presence of allergens, such as pet dander and pest droppings.
• Controlling moisture levels through proper ventilation and humidity control can inhibit the growth of mould, mildew, and bacteria.
• Integrated pest management strategies can be employed to reduce the presence of insects and other pests.
• Exhaust fans in kitchens and bathrooms can reduce organic pollutants and moisture buildup.
• Maintaining clean bedding and mattress covers can create a barrier against allergens.

Fungi, moulds, and mildews

Moulds, a type of fungus, grow in various shapes, sizes, and colours, often with a fuzzy or dusty texture due to the production of asexual spores. Moulds require oxygen, moisture, and food sources such as wood, paper, and certain glues found in building materials. They can colonize porous building materials, leading to indoor air quality issues. Mould spores are drawn to specific environments, and high moisture levels facilitate their growth. Contaminated ventilation and air handling systems can become breeding grounds for mould, distributing spores throughout a building.

Mould exposure can cause allergic reactions, including asthma, hypersensitivity pneumonitis, allergic rhinitis, and other respiratory issues. Some mould species produce mycotoxins, which are toxic secondary metabolites. These mycotoxins can lead to adverse health effects when inhaled or consumed through mould-contaminated food. Therefore, it is crucial to control moisture levels and promptly address water damage to prevent mould growth and reduce the risk of biological pollution indoors.

Mildew, another type of fungus, typically grows in a flat, powdery pattern and is commonly found on painted wood or crops in humid environments. While mildew on painted surfaces may cause disfigurement, it does not pose a direct health hazard to humans. However, mildew affecting plants and crops can result in damage, impacting agricultural productivity.

To minimize the impact of fungi, moulds, and mildews on biological pollution, it is essential to maintain recommended humidity levels in indoor environments, promptly address water damage, and implement corrective measures to control moisture and promote cleanliness.

Frequently asked questions