The Murky Truth: Unveiling The Color Of Polluted Water

The colour of water can vary depending on the presence of impurities and the ambient conditions. Pure water has a slight blue tint, which becomes more prominent as the thickness of the observed sample increases. However, water can appear colourless in small quantities. The presence of dissolved minerals, sediment, and other contaminants can give water a different colour, such as brown, green, or even beige. Water pollution can be caused by various factors, including industrial waste, agricultural runoff, and sewage discharge, resulting in discoloured water that can pose health risks and environmental hazards.

Polluted water can be blue-green, indicating the presence of cyanobacteria

Polluted water can sometimes appear blue-green, which is indicative of the presence of cyanobacteria, also known as blue-green algae. While not all blue-green algae are harmful, certain varieties produce toxins that can be dangerous to humans and animals. These toxins can lead to illnesses or even death in those who come into contact with or consume the contaminated water.

Cyanobacteria are a type of microscopic, algae-like bacteria that inhabit freshwater, coastal, and marine waters. They play a significant role in aquatic ecosystems by photosynthesising like plants, producing oxygen, and forming the base of the food chain. However, when cyanobacteria multiply rapidly due to favourable conditions, they can form large 'blooms'. These blooms are often visible and can result in poor water quality and potential toxicity.

Blooms typically occur during warm seasons when water temperatures are high, and they are more common in still or slow-moving waters such as lakes and ponds. However, they can also occur in streams, especially if the water flow is slow or pooled. Nutrient pollution, caused by excess nitrogen and phosphorus, is a significant contributor to the growth of cyanobacterial blooms. These nutrients can enter water systems through various human activities, including agricultural practices, wastewater discharge, and stormwater runoff.

The presence of cyanobacterial blooms can have detrimental effects on human, livestock, and pet health, as well as on aquatic ecosystems. In addition to producing toxins, these blooms can severely reduce or eliminate oxygen in the water, leading to fish kills. Therefore, it is essential to monitor and control cyanobacterial outbreaks to protect public health and the environment. Local councils and state water authorities play a crucial role in investigating suspected outbreaks and alerting the public about unsafe water conditions.

While polluted water can sometimes appear blue-green due to cyanobacteria, it is important to note that water colour is not always a reliable indicator of pollution. Pure water, free from contaminants, has a slight blue tint due to the absorption of light by water molecules. Other factors, such as sediment, organics, and dissolved minerals, can also influence the colour of water, resulting in shades of brown or green, even when the water is safe to drink.

Brown water can be caused by iron or rust in water pipes

Pure water is not actually colourless, but has a slight blue tint. However, the water we use in our daily lives is not pure and often contains dissolved minerals and suspended materials, which can affect its colour. Brown drinking water is usually an indication of high iron content, which can give it a metallic taste and an orange-to-brown hue. Iron is a common, naturally occurring metal in soil, and is typically present in drinking water in small quantities. However, if there is too much iron in the water, it can cause it to turn brown.

Brown water can also be caused by rust in water pipes. Rust may break out from old, galvanized steel pipes and contaminate the water supply. This is more likely to occur if the pipes are broken or have recently been replaced, as the disturbance and shift in pressure can allow old rust to enter the water system. A sudden increase in water flow through the pipes can also cause rust to dislodge and enter the water supply. This could be due to a water main break, high service demand, or even excessive water use, such as in firefighting.

If you notice that your tap water is brown, it is recommended that you do not drink it, as it could be a breeding ground for bacteria. It is also important to note that brown water can damage your clothes and fixtures, and may even cause hives. If the problem persists, you should contact your town or city's utility provider to inspect and flush out the pipes. If the brown water is only coming from your hot water tap, the problem may be with your water heater, which may need to be flushed out or replaced.

White or milky water is often caused by air in the water

Water pollution is a serious issue, with many chemicals, waste materials, and other contaminants degrading water quality. Even pure water is not entirely colorless, exhibiting a slight blue tint. However, when water appears white or milky, it is often due to air dissolved in the water supply.

White or milky water is typically caused by air mixing with water due to pipe issues, changes in water pressure, pipe disruptions, or nearby drilling activities stirring up sediment. This can occur when there is a breach or rupture in the pipes, allowing extra air to enter and mix with the water. As a result, when you turn on the tap, the pressure is released, and tiny air bubbles are formed, giving the water a cloudy or milky appearance. This phenomenon is similar to what happens when you open a carbonated drink, and the dissolved gas escapes, forming bubbles.

While the sight of white or milky water may be concerning, it is important to know that it is generally harmless and safe for drinking and other uses. The cloudiness and air bubbles do not indicate contamination and will usually disappear within 24 hours. If you want to confirm that the cloudiness is due to air, a simple test can be performed. Fill a clean glass with cold tap water and let it sit on the counter. Observe the glass, and if the cloudiness starts to clear from the bottom up, it is due to air in the water.

Although milky water is typically temporary and harmless, it can affect the taste, smell, and aesthetic of your water. It can also lead to the formation of a white residue on fixtures, which can be easily removed using vinegar or lemon juice. If the issue persists beyond 24 hours, it is recommended to contact a certified plumber or your water supplier for further assistance and to ensure there are no underlying issues.

To summarize, white or milky water is often a result of air mixing with water due to various factors, and while it is generally harmless, it can be aesthetically unpleasing and may impact the taste and smell of your water. Regular maintenance and proactive steps can help improve water quality and prevent such issues.

Maroon or beige water can indicate the presence of organic matter or suspended particles

Water pollution is a widespread problem that jeopardizes human health. It occurs when harmful substances contaminate a body of water, degrading water quality and rendering it toxic. While there are many sources of water pollution, including toxic substances from farms, towns, and factories, organic matter is also a significant contributor. Organic matter is composed of organic compounds that come from the feces and remains of organisms such as plants and animals. This matter is common throughout the ecosystem and plays a crucial role in the movement of nutrients in the environment and water retention.

Aquatic organic matter can be classified into two components: dissolved organic matter (DOM) and particulate organic matter (POM). DOM is measured as colored dissolved organic matter (CDOM) or dissolved organic carbon (DOC), while POM refers to organic matter that cannot pass through a 0.45 micrometre filter. Natural organic matter (NOM) is an extremely complex mixture of organic compounds found in all groundwater and surface waters. While NOM has no direct impact on health, it can affect the efficacy of drinking water treatment processes and contribute to undesirable colors, tastes, and odors in drinking water.

Maroon or beige water can indicate the presence of organic matter, specifically particulate organic matter (POM) that contains organic particles resulting from the decomposition of plant and animal debris in the soil. These particles can range in size from colloidal dimensions to about 100 µm and are composed of inorganic and organic materials derived from soils and rocks, as well as debris from human activity. While the direct health effects of consuming water with suspended particles are unknown, there is concern over the presence of asbestos mineral fibers, which are known to be carcinogenic when inhaled.

Additionally, organic matter can bind to metal ions and minerals in water, leading to the formation of by-products that can induce biofouling and clog water filtration systems. These by-products can be treated with chlorine disinfection (chlorination), but this can also result in the production of disinfection by-products. While there are no established numerical limits for NOM in drinking water, the U.S. Environmental Protection Agency requires the removal of total organic carbon (TOC) by surface water facilities for water with levels of TOC above 2 mg/L.

Pink water, like in Australia's Lake Hillier, is caused by pink-coloured algae

Water colour is influenced by several factors, including dissolved minerals, sediments, and organic compounds. Pure water is not entirely colourless, exhibiting a slight blue tint due to the absorption of light by water molecules. However, when it comes to polluted water, various contaminants can alter its colour significantly.

Pink water, as observed in Australia's Lake Hillier, is a fascinating example of water colour influenced by specific organisms. The distinct pink hue of Lake Hillier is primarily attributed to the presence of pink-coloured algae, specifically Dunaliella salina. This type of algae is known for producing pigment compounds called carotenoids, which aid in sunlight absorption and contribute to their reddish-pink colour.

Dunaliella salina is a highly salt-tolerant species, capable of thriving in hypersaline environments with salinity levels as high as 35% NaCl, which is significantly higher than the salinity of seawater, typically around 3% NaCl. The high salt content in Lake Hillier's water, up to ten times saltier than seawater, creates the ideal environment for this salt-loving algae to flourish.

While D. salina plays a significant role in the pink colouration of the lake, it is not the sole contributor. Researchers have identified other microbes and bacteria that also influence the lake's unique pigmentation. Among them is the bacterium Salinibacter ruber, which was found to constitute a notable proportion of the DNA recovered from the lake. Additionally, the climate and hydrology of the continent beneath the lake play a role in its colour. Warmer weather and lower rainfall, along with increased evaporation leading to higher salinity, can enhance the pink hue.

The pink water of Lake Hillier is a striking natural phenomenon that has captivated both tourists and scientists alike. It serves as a reminder of the intricate interplay between various factors, including algae, bacteria, and environmental conditions, that can result in the unusual colouration of bodies of water.

Frequently asked questions