Environmental Chemistry Glossary

The process by which acidic substances (wet or dry) are deposited from the atmosphere onto Earth's surface, including acid rain, fog, and dry particulate fallout.

The adhesion of molecules to a solid surface, distinct from absorption. Important in contaminant binding to soil particles and activated carbon filtration.

The gradual accumulation of a substance in an organism when the rate of intake exceeds the rate of metabolism and excretion.

The pathway by which a chemical element or molecule moves through the atmosphere, hydrosphere, lithosphere, and biosphere.

The increase in concentration of a persistent substance at successively higher trophic levels in a food chain.

The use of biological organisms to remove or neutralize environmental contaminants from polluted sites.

The quantity of dissolved oxygen required by aerobic microorganisms to decompose organic matter in a water sample, used as a measure of water pollution.

The long-term capture and storage of atmospheric carbon dioxide in geological formations, oceans, soils, or biomass.

A measure of the total quantity of oxygen required for chemical oxidation of organic and inorganic matter in water.

The concentration of molecular oxygen dissolved in water, essential for supporting aquatic life.

The enrichment of a water body with excess nutrients, leading to algal blooms, oxygen depletion, and ecological degradation.

A measure of how much energy a mass of greenhouse gas absorbs over a given time period relative to the same mass of $\text{CO}_2$.

The time required for the concentration or amount of a substance to decrease to half its initial value through degradation or decay.

Metallic elements with high density and potential toxicity, including mercury, lead, cadmium, arsenic, and chromium.

The downward transport of dissolved substances through soil by percolating water, potentially contaminating groundwater.

The tendency of a compound to dissolve in fats, oils, and nonpolar solvents. Lipophilic pollutants tend to bioaccumulate in fatty tissues.

Plastic particles smaller than 5 mm in diameter, arising from degradation of larger plastics or manufactured as microbeads.

The biochemical conversion of atmospheric dinitrogen ($\text{N}_2$) into ammonia ($\text{NH}_3$) or related compounds available to organisms.

A triatomic form of oxygen ($\text{O}_3$). Beneficial in the stratosphere where it absorbs UV radiation; harmful at ground level where it is a major component of smog.

An organic compound that resists degradation, bioaccumulates in living organisms, and can be transported long distances through the environment.

A logarithmic scale measuring the acidity or basicity of a solution, ranging from 0 (most acidic) to 14 (most basic), with 7 being neutral.

The chemical decomposition of a substance caused by the absorption of light, particularly ultraviolet radiation.

The use of plants and their associated microorganisms to remove, degrade, or contain environmental contaminants.

The lowest layer of Earth's atmosphere, extending from the surface to about 12 km altitude, where most weather and air pollution occur.

An organic chemical that readily evaporates at room temperature, contributing to air pollution and photochemical smog formation.