Polluted Water: Hidden Dangers Lurking In Liquid Form

Water pollution is a pressing issue that poses a significant threat to human health. Unsafe water is responsible for more deaths each year than war and all other forms of violence combined, with contaminated water causing approximately 1.8 million deaths in 2015. The primary sources of water pollution include industrial waste, agricultural runoff, sewage, and plastic waste. These pollutants introduce harmful chemicals, heavy metals, and pathogens into water sources, leading to the contamination of drinking water and the degradation of aquatic ecosystems.

The consumption of polluted water can have severe health consequences. It is linked to various diseases, including cholera, dysentery, typhoid, and polio, with diarrhoeal diseases being the most common. In addition, water pollution can cause gastrointestinal illnesses, nervous system disorders, reproductive issues, and chronic conditions such as cancer. The impact of water pollution on health can vary depending on factors such as the type of contaminant, its concentration, individual susceptibility, and the duration of exposure.

The effects of water pollution extend beyond physical health, as it also has social and economic repercussions. Communities, especially those in low-income areas, bear the brunt of the impact, as their proximity to polluting industries puts them at higher risk. Additionally, inadequate water management and sanitation systems further exacerbate the problem, leading to preventable health risks.

Microplastics

The World Health Organization (WHO) has published a report on the impact of microplastics in drinking water on human health. The report outlines three possible routes by which microplastics could impact human health:

• Physical: Microplastics could enter the body and damage internal structures.
• Chemical: For instance, plastic additives such as plasticizers could enter drinking water.
• Biofilm: Microorganisms might attach to microplastics and form colonies, which could cause harm.

The WHO report concludes that larger microplastics (bigger than 150 micrometres) probably do not enter the human body, while smaller particles may get in but their uptake is limited. The report also states that absorption of nanosized particles might be more common, but data on this is limited.

While the WHO report suggests that microplastics in drinking water do not pose a significant health risk at current levels, it also calls for more research to fully understand the potential risks. The report recommends reducing plastic pollution by phasing out single-use plastics and promoting recycling and the use of alternatives.

Some studies have found potential health risks associated with ingesting microplastics. A 2020 study estimated that humans ingest between 0.1 and 5 grams of microplastics weekly. Other studies have shown that microplastics may cause oxidative stress, inflammatory reactions, and metabolic disorders in humans. However, more research is needed to confirm these effects and fully understand the potential risks of microplastics on human health.

Sewage and wastewater

The World Health Organization (WHO) notes that globally, around 1.7 billion people use drinking water sources with faecal contaminants. Contaminated water can harbour bacteria, such as those responsible for cholera, dysentery, typhoid, hepatitis A, and polio. According to the WHO, approximately 1.4 million people die each year due to poor sanitation, poor hygiene, or unsafe drinking water.

The impact of sewage and wastewater on human health is significant. According to the 2021 World Water Development Report by UNESCO, about 829,000 people die annually from diarrhoea caused by unsafe drinking water, sanitation, and hand hygiene, including 300,000 children under the age of five. Diarrhoea is the most common disease caused by water pollution, mainly transmitted by enteroviruses in the aquatic environment.

Untreated or partially treated wastewater is often used for irrigation in water-scarce regions, leading to serious agricultural land and food pollution. Pesticides, for example, can have an adverse impact on health through drinking water. A 10% increase in pesticide use was found to result in a 1% increase in the medical disability index for those over 65 years of age.

In addition to gastrointestinal illnesses, unsafe drinking water and poor environmental hygiene can lead to malnutrition, particularly in children. Water pollution can also cause skin diseases. Arsenic in drinking water, for instance, has been linked to skin disorders such as melanosis and keratosis.

Furthermore, sewage and wastewater can introduce carcinogens into the water supply. Arsenic, nitrate, and chromium in drinking water have been associated with an increased risk of various types of cancer, including skin, kidney, bladder, lung, and liver cancer.

Oil pollution

Oil spills can have disastrous consequences for society, including economic, environmental, and social impacts. They can also have immediate negative effects on human health, including respiratory and reproductive problems, liver and immune system damage, and even death. Oil spills can contaminate drinking water supplies, and the chemicals in crude oil, such as benzene, toluene, and poly-aromatic hydrocarbons, can introduce adverse health effects when inhaled.

Oil spills can affect animals and plants in two ways: directly from the oil and from the response or cleanup process. Oil penetrates the structure of the plumage of birds and the fur of mammals, reducing their insulating ability and making them more vulnerable to temperature fluctuations and less buoyant in the water. Oil can impair a bird's ability to fly, and as they preen, they may ingest the oil, irritating the digestive tract and causing kidney damage. Heavily furred marine mammals exposed to oil spills are affected in similar ways, with oil reducing their insulation and leading to hypothermia. Oil can also blind animals, leaving them defenseless, and it can be poisonous if ingested, causing death if it enters the lungs or liver.

Oil spills can be caused by human error, natural disasters, technical failures, or deliberate releases. It is estimated that 30-50% of all oil spills are directly or indirectly caused by human error, and approximately 20-40% are attributed to equipment failure or malfunction. Oil tanker spills are considered a major ecological threat due to the large amount of oil spilled per accident and the proximity of major sea traffic routes to large marine ecosystems.

Cleanup and recovery from an oil spill are difficult and depend on factors such as the type of oil spilled, water temperature, and the types of shorelines and beaches involved. Physical cleanups are very expensive, and chemical remediation is now the norm, using compounds to herd and thicken oil for physical recovery, disperse it in the water, or facilitate burning it off.

Radioactive waste

Evaporation concentration is a proven method for reducing the amount of radioactive wastewater. It involves heating the radioactive waste to evaporate the water, which is then cooled and condensed, while the non-volatile radionuclides remain and are concentrated. This method has a high decontamination coefficient and volume reduction effect and can be combined with various other technologies.

Ion exchange is a technology that uses ions on an ion exchanger to separate and extract specific ions from a dilute solution. It is suitable for treating waste liquids with low salt content and is often used for low-level radioactive waste.

Chemical precipitation is a simple, cost-effective method that co-precipitates the precipitant and radionuclides in the waste liquid. Common precipitants include aluminum salts, phosphates, iron salts, and soda. This method has difficulty removing certain radionuclides, like cesium, and solid-liquid separation can be challenging.

Membrane separation uses membranes with selective separation to purify, concentrate, or separate substances. Different types of membranes, like reverse osmosis, ultrafiltration, nanofiltration, and microfiltration, can be used depending on the composition of the radioactive waste. Membrane separation has advantages such as energy efficiency and flexibility but is limited by membrane fouling and radioactive exposure, which can decrease membrane performance and lifespan.

Biotechnology uses plants or microbial cells to remove radionuclides through biotransformation, biosorption, bioaccumulation, sedimentation, and solubilization mechanisms. It is environmentally friendly, efficient, mild, low-cost, and does not produce secondary pollution. However, it is greatly affected by environmental factors like pH, type of nuclide, and initial concentration.

Photocatalysis converts solar energy into chemical energy using a photocatalyst. It can be used to treat organic wastewater and has been proposed as a potential treatment for radioactive wastewater, especially macromolecular organic waste liquids.

Fertilizers and pesticides

• Neurological issues: Exposure to fertilizers and pesticides can affect the nervous system, leading to reduced attention span, memory disturbances, and in some cases, the onset of Parkinson's disease.
• Reproductive problems: Pesticides can interfere with hormone balance and have been linked to reproductive issues, including reduced sperm count and quality.
• Immune system dysfunction: Prolonged exposure to fertilizers and pesticides can result in immunosuppression, making individuals more susceptible to infections and diseases.
• Respiratory issues: The use of fertilizers and pesticides has been associated with an increased risk of respiratory problems, including asthma and bronchitis.
• Cancer: Certain pesticides are known to be carcinogenic, with long-term exposure increasing the risk of developing cancer, especially in children.
• Gastrointestinal issues: Ingesting contaminated water containing fertilizers and pesticides can lead to gastrointestinal problems such as nausea, vomiting, and diarrhea.
• Cardiovascular issues: Studies have suggested a link between chronic exposure to low doses of pesticides and an increased risk of cardiovascular diseases.

Sources of Water Contamination by Fertilizers and Pesticides:

The use of fertilizers and pesticides in agriculture is a significant source of water contamination. Here are some common ways fertilizers and pesticides can enter water bodies:

• Runoff: Rainwater can wash fertilizers and pesticides from farms into nearby waterways, leading to contamination.
• Leaching: Soluble fertilizers and pesticides can be carried by water molecules, percolating downward into the soil and eventually reaching groundwater and surface water sources.
• Erosion: Soil erosion can carry fertilizers and pesticides into rivers, lakes, and other water bodies, leading to contamination.
• Spills and improper disposal: Accidental spills or improper disposal of fertilizers and pesticides can directly contaminate water sources.

Preventing Water Contamination by Fertilizers and Pesticides:

To reduce the impact of fertilizers and pesticides on human health, it is essential to minimize their release into water bodies. Here are some strategies to prevent water contamination:

• Adopting sustainable agricultural practices: This includes using organic fertilizers, reducing pesticide usage, and implementing integrated pest management strategies.
• Proper storage and handling: Storing fertilizers and pesticides in secure, spill-proof containers can prevent accidental spills.
• Educating farmers: Educating farmers on the proper use, handling, and disposal of fertilizers and pesticides can help reduce the risk of water contamination.
• Implementing regulations: Governments and regulatory bodies should enforce guidelines and regulations to ensure the safe use and disposal of fertilizers and pesticides.

Frequently asked questions