Water Quality Standards and Pollution Assessment

Any alteration to the environment that harms living organisms.

A pollution source that is localized and easily identifiable. For example, a chemical discharge pipe.

A widespread pollution source that is difficult to pinpoint. For example, agricultural runoff.

The process of making a substance less concentrated. Example: pouring a glass of juice into a pitcher of water.

A measure of the amount of a substance in a given volume. Example: the amount of salt in a liter of water.

A measure of how poisonous a substance is. It is measured as the lethal dose (LD50), which is the amount of the substance that causes 50% of test animals to die when given a specific dose.

A substance that can cause serious health problems or death. It is often harmful to living organisms.

Living organisms, such as fish, plants, worms, and insects, that indicate the health of a water body.

Microscopic organisms, like bacteria, that can cause health problems. Their presence in water indicates potential contamination.

The amount of oxygen dissolved in water, which is essential for aquatic life.

A way to measure the concentration of pollutants in the environment, expressed as parts per million (ppm) or parts per billion (ppb).

The substance that is being dissolved in a solution.

The substance that dissolves another substance in a solution.

The amount of a substance that will kill 50% of a population.

The maximum dose of a substance that can be given to an organism without reaching its lethal level.

The amount of arsenic required to reach the LD50 for a 1.75 kg duck is 22.75 mg.

The LD50 value specifically for caffeine is 150-200 milligrams per kilogram of body mass.

The lethal dose of caffeine for a 55 kg person is approximately 9625 mg.

The maximum recommended daily caffeine intake for adults is typically below 400 mg.

The study of how different substances affect different organisms, particularly the differences between human and animal responses.

Every chemical can potentially cause harm depending on the type, duration, and amount of exposure.

The trapping of heat in the Earth's atmosphere by greenhouse gases such as water vapor, carbon dioxide, and methane.

An increase in the Earth's average temperature caused by the buildup of greenhouse gases in the atmosphere.

The scattering of a substance away from its source.

The process of reducing the concentration of a pollutant by mixing it with a large amount of air or water.

The movement of airborne and waterborne chemicals through the environment.

The zone in the soil where groundwater is collected. The top of this zone is called the water table.

The release of a chemical at its source, followed by its dispersion in the atmosphere and deposition in soil or water.

The movement of pollutants through the ground, with their concentration potentially increasing in certain areas.

Air pollution, a major environmental concern, can travel far beyond its point of origin thanks to prevailing winds like circumpolar winds, which carry pollutants across vast distances in the northern hemisphere. This effect can lead to air contamination hundreds of kilometers from the source.

Sulfur dioxide (SO2), a major air pollutant, contributes to smog and acid rain. It is primarily produced through industrial processes and the burning of sulfur-containing fuels. However, scrubbers are able to reduce these emissions by a significant margin, up to 99%, by removing impurities from gases.

Carbon monoxide is known as the "silent killer" due to its colorless and odorless nature. It is a dangerous gas, produced primarily by motor vehicles, that reduces oxygen levels in the blood, leading to potential health risks including headaches, sleepiness, chest pains, and even death. Other sources include wood burning (especially forest fires), natural gas, industrial processes, airplanes, and cigarettes.

Catalytic converters, a vital part of car exhaust systems, play a crucial role in reducing carbon monoxide emissions by converting it into carbon dioxide. This conversion process helps to minimize the harmful effects of carbon monoxide on human health and the environment.

Ground-level ozone, a colorless and odorless gas, is formed through reactions in the atmosphere involving oxygen, nitrogen oxides, and volatile organic compounds (VOCs). The presence of sunlight is essential for this formation process. It's important to note that ground-level ozone is distinct from the protective ozone layer in the stratosphere.

While carbon dioxide occurs naturally, human activities are rapidly increasing its levels in the atmosphere. This rise is a growing global concern because carbon dioxide acts as a greenhouse gas, trapping heat and contributing to climate change.