Water Contamination Vs. Pollution: What's The Real Difference?

Water pollution, or aquatic pollution, is the contamination of water bodies, which can negatively impact their uses. Water contamination is the presence of a foreign or undesirable substance in water, but it does not always cause harm. Water pollution, on the other hand, is caused by human activity and results in adverse biological effects on resident communities. All pollutants are contaminants, but not all contaminants are pollutants. While water contamination and water pollution are interconnected, they have notable differences.

Is water contamination the same as water pollution?

Point source vs. non-point source pollution

Water contamination and water pollution are closely related concepts. Water contamination refers to the presence of an external substance or material in water, regardless of whether it is harmful. Water pollution, on the other hand, specifically refers to the presence of substances that can cause harm to humans, animals, and plants or degrade water quality and generate apparent effects. Therefore, all pollutants are contaminants, but not all contaminants are pollutants.

Now, let's delve into the differences between point source and non-point source pollution:

Point source pollution refers to contamination originating from a single, identifiable source. Examples include wastewater discharged by a manufacturer, oil refinery, or wastewater treatment facility, as well as leaking septic systems, chemical and oil spills, and illegal dumping. The Environmental Protection Agency (EPA) regulates point source pollution by setting limits on what can be discharged directly into a body of water. While it originates from a specific place, point source pollution can impact miles of waterways and oceans.

Non-point source pollution, on the other hand, is derived from diffuse sources and does not have a single, identifiable culprit. This type of pollution is more challenging to regulate and address. Examples of non-point source pollution include agricultural or stormwater runoff, debris blown into waterways, and discarded trash. Non-point source pollution is the leading cause of water pollution in U.S. waters.

Sediment and nutrients are significant contributors to non-point source pollution. Sediment can include soil particles from construction sites, stream banks, cropland, or residential renovation, making the water cloudy or "turbid," which hinders fish feeding and breathing. Nutrients, primarily phosphorus and nitrogen, from sources like manure, pet waste, failed septic systems, and fertilizer overuse, contribute to excessive aquatic plant growth, leading to eutrophication and oxygen depletion in the water.

Understanding the differences between point source and non-point source pollution is crucial for effective water quality management and protection. By identifying the sources of pollution, whether point or non-point, appropriate measures can be implemented to mitigate their impact and preserve water resources for human, recreational, and economic purposes.

Groundwater contamination

Groundwater is a vital resource for millions of people worldwide, providing drinking water to many. It starts as precipitation and, once it penetrates the ground, it continues to move, sometimes quickly and sometimes slowly.

Another source of groundwater contamination is uncontrolled hazardous waste sites. In the United States alone, there are over 20,000 known abandoned and uncontrolled hazardous waste sites, and this number continues to grow. If there are leaks from these sites, contaminants can eventually make their way through the soil and into the groundwater. Landfills are meant to have a protective bottom layer to prevent contaminants from getting into the water, but if this layer is missing or damaged, contaminants such as car battery acid, paint, and household cleaners can leach into the groundwater.

Atmospheric contaminants can also play a role in groundwater contamination. Since groundwater is part of the hydrologic cycle, contaminants from other parts of the cycle, such as the atmosphere or surface water, can be transferred to groundwater supplies. Industrial discharges, urban activities, agriculture, groundwater pumpage, and waste disposal can all negatively impact groundwater quality. Leaking fuel tanks, toxic chemical spills, and the widespread use of chemicals and road salts further contribute to groundwater contamination.

The effects of groundwater contamination can be severe and long-lasting. Contaminated groundwater can harm both human health and wildlife, with exposure leading to certain types of cancer and other health issues. Once an aquifer is polluted, it may be unusable for decades or even thousands of years. Groundwater contamination can also spread contamination far from the original source as it seeps into streams, lakes, and oceans, impacting aquatic ecosystems and reducing ecosystem services such as drinking water provision.

Surface water contamination

Water contamination and water pollution are closely related concepts. While contamination refers to the presence of a foreign substance in a material, pollution occurs when the concentration of that substance is high enough to impair the material's quality and produce observable effects.

Surface water is any body of water found on the Earth's surface, including oceans, lakes, rivers, and streams. Surface water pollution, therefore, refers to the contamination of these water bodies. Surface water is at risk of pollution because it is a "universal solvent", meaning it can easily dissolve substances more rapidly than any other liquid on Earth.

There are four main sources of surface water pollution: agricultural runoff, sewage/wastewater, oil pollution, and radioactive substances. The biggest pollutant that surface water faces usually comes from fertilizers and other harmful chemicals used on farms, in homes, and on infrastructure such as roads. Sewage leaks and waste products from farms that leach into the environment also contribute to surface water pollution. These pollutants are very harmful to human water supplies because fertilizers and sewage waste carry many pathogens and waterborne diseases.

Other causes of surface water pollution include contaminated rainwater runoff, industrial waste discharges, and individuals dumping pollutants into waterways. Once surface water is contaminated, it can have serious health implications when consumed unfiltered, and it can also harm aquatic animals and plants that rely on these environments.

To address surface water pollution and protect water sources, it is essential to understand where the pollution is coming from (point source or non-point source) and the type of water body being impacted.

Contaminants vs. pollutants

Water contamination and water pollution are two related but distinct concepts. While the terms "contaminant" and "pollutant" are often used interchangeably, there are important distinctions between them.

Contaminants:

Contaminants are substances that are foreign to the environment and are not wanted or needed. They are introduced by humans into the environment through various means, such as industrial activities, agricultural activities, and urban runoff. Contaminants can include organic and inorganic substances, such as sewage discharges, chemical compounds, and personal care products. For example, a pen thrown into a body of water could be considered a contaminant. While contaminants may be undesirable, they do not necessarily cause harm. The level of concentration of contaminants is typically within acceptable limits and does not always result in adverse effects.

Pollutants:

Pollutants, on the other hand, are materials consisting of waste that can cause harm to the environment or human health. They are often the result of human activities and can exist in various forms, such as smoke, chemicals, and toxic substances. Pollutants can include organic pollutants, metals, plastics, pesticides, and industrial waste products. For example, high concentrations of minerals or toxic substances in water can make it unfit for drinking and harmful to life. The level of concentration of pollutants is sufficient to degrade water quality and generate observable effects.

Relationship between Contaminants and Pollutants:

All pollutants are contaminants, but not all contaminants are pollutants. The distinction between the two lies in the potential for harm. Contaminants become pollutants when their concentration exceeds a certain threshold and begins to impair water quality and negatively affect human use or ecological systems. This threshold can vary depending on species and environmental factors, and it may be challenging to determine precisely when a contaminant becomes a pollutant.

Human activities causing water pollution

Water contamination and water pollution are closely related concepts. Contamination refers to the presence of a foreign substance in water, which may or may not be harmful. On the other hand, pollution refers to contamination that has adverse biological effects on humans, animals, and plants. In other words, all pollutants are contaminants, but not all contaminants are pollutants.

Human activities are a major cause of water pollution. Here are some ways in which human activities contribute to this pressing issue:

• Agricultural Activities: The use of pesticides, herbicides, and fertilizers in agriculture can lead to water pollution. When these chemicals are applied to crops, they can be washed away by rainwater and end up in nearby water bodies, a process known as agricultural runoff. This contributes to nutrient pollution, which includes nitrates and phosphates, and can lead to eutrophication (the blooming of harmful algae) in aquatic ecosystems.
• Industrial Activities: Industries often discharge untreated or partially treated wastewater into water bodies, containing toxic substances such as heavy metals (mercury, arsenic, lead, etc.), chemical compounds, and industrial waste products. These contaminants can have severe ecological and human health impacts, including bioaccumulation in species higher up in the food chain, such as fish consumed by humans.
• Urban and Stormwater Runoff: Urban areas contribute to water pollution through stormwater runoff, which carries debris, oils, salts, and other contaminants into water bodies. Additionally, urban areas generate large amounts of waste, including plastic waste and sewage, which can end up in oceans and other water sources, posing a significant threat to marine life.
• Sewage Discharges: Raw or improperly treated sewage can contain harmful bacteria, viruses, and chemical compounds from personal hygiene and cosmetic products. These contaminants can lead to waterborne diseases and negatively impact aquatic ecosystems.
• Power Plants and Manufacturing: The use of water as a coolant by power plants and industrial manufacturers can result in thermal pollution, causing changes in water temperature that can harm aquatic life.
• Pharmaceuticals and Personal Care Products: The presence of pharmaceutical drugs and personal care products in water bodies is an emerging concern. These products can contain biologically active components that can have toxicological effects on aquatic life, such as the feminization of male fish due to oral contraceptives or the development of antimicrobial resistance due to antibiotics.
• Oil Spills and Fuel Combustion: Oil spills and the combustion of fuels (such as gasoline, diesel, and fuel oil) can introduce petroleum hydrocarbons into water bodies, causing pollution and endangering aquatic life.

These are just a few examples of how human activities contribute to water pollution. It is important to recognize the impact of these activities and work towards mitigating their negative effects to protect our precious water resources and the ecosystems that depend on them.

Frequently asked questions