Unit 8 — Aquatic and Terrestrial Pollution

air pollutants

Harmful substances released into the atmosphere that can negatively affect air quality and human health.

nonpoint source

A diffused source of pollution that is difficult to identify, such as pesticide spraying or urban runoff.

point source

A single, identifiable source of pollution, such as a smokestack or waste discharge pipe.

urban runoff

Water from precipitation that flows over urban surfaces such as pavement and roofs, carrying pollutants into water systems rather than infiltrating into the ground.

composting

The process of organic matter such as food scraps, paper, and yard waste decomposing into a product that can be used as fertilizer.

electronic waste

Electronic waste from discarded electronic devices that may contain hazardous chemicals including heavy metals such as lead and mercury.

heavy metals

Dense metallic elements such as mercury, lead, and cadmium that are toxic to organisms and can accumulate in ecosystems.

landfill gas combustion

The burning of gases produced from decomposition of organic material in landfills to generate electricity and reduce landfill volume.

landfill mitigation strategies

Methods used to reduce the negative impacts of landfills, ranging from burning waste for energy to restoring habitat on former landfills.

leaching

The process by which hazardous chemicals and heavy metals from landfills seep into groundwater.

organic matter

Biodegradable material in sewage that bacteria break down during secondary treatment.

recycling

A process by which certain solid waste materials are processed and converted into new products to reduce demand on natural resources.

aeration

The process of introducing air into sewage treatment tanks to increase the rate at which bacteria break down organic matter.

disinfection

The process of exposing treated water to disinfectants such as chlorine, ozone, or UV light to kill bacteria before discharge.

inorganic sludge

Solid waste produced when bacteria break down organic matter during secondary treatment, which settles at the bottom of a tank.

organic matter

Biodegradable material in sewage that bacteria break down during secondary treatment.

primary treatment

The first stage of sewage treatment involving physical removal of large objects through screens and grates, followed by settling of solid waste in a tank.

secondary treatment

A biological process in sewage treatment where bacteria break down organic matter into carbon dioxide and inorganic sludge, with aeration to increase the rate of decomposition.

tertiary treatment

The use of ecological or chemical processes to remove remaining pollutants from water after primary and secondary treatment.

chemical

A substance with a definite molecular composition that can cause toxic effects in organisms.

dose

The amount of a toxin or drug administered to or received by an organism.

lethal dose 50% (LD50)

The dose of a chemical that is lethal to 50% of the population of a particular species.

dose

The amount of a toxin or drug administered to or received by an organism.

dose response curve

A graph that describes the relationship between the dose of a toxin or drug and its effect on an organism or mortality rate in a population.

mortality rate

The proportion or number of deaths in a population resulting from exposure to a particular substance or condition.

toxin

A poisonous substance that can cause harmful effects or death in an organism.

asbestos

A mineral substance that causes mesothelioma and other health problems when inhaled.

dysentery

A disease caused by untreated sewage in streams and rivers that affects the digestive system.

mesothelioma

A type of cancer caused mainly by exposure to asbestos.

respiratory problems

Health issues affecting the lungs and breathing system that can be caused by air pollutants such as tropospheric ozone.

tropospheric ozone

Ground-level ozone in the lower atmosphere that can impair respiratory function and lung health when present at elevated levels.

cholera

A bacterial disease contracted from infected water supplies.

climate zones

Geographic regions characterized by distinct temperature and precipitation patterns that influence the distribution of pathogens and diseases.

contaminated drinking water

Water supplies that contain harmful pathogens or pollutants and pose a risk to human health.

infectious diseases

Diseases caused by pathogens that can be transmitted from one organism to another.

malaria

A parasitic disease transmitted to humans through bites from infected mosquitoes.

MERS

Middle East Respiratory Syndrome, a viral respiratory illness transmitted from animals to humans.

pathogen adaptation

The process by which pathogens evolve to exploit new opportunities to infect and spread through human populations.

pathogens

Organisms or agents that cause disease in humans and other organisms.

plague

A bacterial disease transmitted to humans through bites from infected organisms or contact with contaminated fluids or tissues.

sanitary conditions

Environmental conditions related to cleanliness and hygiene that affect disease transmission.

sanitary waste disposal

The safe and hygienic removal and treatment of human waste to prevent disease transmission.

SARS

Severe acute respiratory syndrome, a form of pneumonia transmitted by inhaling or touching infected fluids.

tuberculosis

A bacterial infection that typically attacks the lungs and is spread through inhalation of bacteria from an infected person's bodily fluids.

vectors

Organisms that transmit pathogens from one host to another, such as mosquitoes or fleas.

West Nile virus

A viral disease transmitted to humans through bites from infected mosquitoes.

Zika

A virus transmitted to humans through bites from infected mosquitoes and through sexual contact.

aquatic ecosystems

Water-based ecosystems including oceans, rivers, lakes, and wetlands that support diverse organisms and ecological processes.

coral reefs

Marine ecosystems built by coral organisms that provide habitat for diverse species and are sensitive to temperature changes, sediment, and fishing practices.

dead zones

Areas in oceans with very low dissolved oxygen levels caused by excess nutrient pollution, making them unable to support most aquatic life.

destructive fishing practices

Fishing methods that damage marine ecosystems, including coral reefs and seafloor habitats.

dissolved oxygen

Oxygen gas dissolved in water that aquatic organisms require for respiration; levels decrease during eutrophication as microbes decompose dead algae.

food chain

A linear sequence showing the transfer of energy and nutrients from one organism to the next, starting with a producer and moving through consumers.

fossil fuels

Non-renewable energy sources formed from ancient organic matter, including coal, oil, and natural gas, that release carbon dioxide when burned.

groundwater

Water stored beneath Earth's surface in soil and rock layers, serving as a smaller reservoir in the hydrologic cycle.

heavy metals

Dense metallic elements such as mercury, lead, and cadmium that are toxic to organisms and can accumulate in ecosystems.

homeostasis

The ability of an organism to maintain stable internal conditions despite changes in the external environment.

hydrocarbons

Organic compounds containing hydrogen and carbon released during fossil fuel combustion that contribute to air pollution.

intestinal blockage

A condition in animals caused by ingesting litter or debris that prevents normal digestion and can be fatal.

light infiltration

The penetration of sunlight through water, which is necessary for photosynthesis by aquatic primary producers.

litter

Solid waste that enters aquatic ecosystems and can harm wildlife through ingestion or entanglement.

mercury

A toxic heavy metal that bioaccumulates in organisms and biomagnifies through food chains, causing neurological and reproductive harm.

methylmercury

A highly toxic organic form of mercury created by bacteria in aquatic environments that accumulates in organisms and food chains.

mining

The industrial process of extracting minerals, ores, and other valuable materials from the Earth.

nutrient pollution

Excess nitrogen and phosphorus in water that causes algal blooms and subsequent oxygen depletion.

ocean temperature

The thermal conditions of ocean water that influence atmospheric temperature, precipitation, and weather patterns.

oil spills

The release of crude oil or refined petroleum into marine waters, causing harm to organisms and ecosystems.

optimum range

The specific conditions for an environmental factor where an organism can best maintain homeostasis and function most effectively.

oxygen sag curve

A graph showing how dissolved oxygen levels decrease and then recover with distance from a pollution source in a waterway.

physiological stress

Physical strain on an organism's body systems that can result from environmental conditions outside its tolerance range.

primary producers

Aquatic organisms such as algae and aquatic plants that produce energy through photosynthesis and form the base of aquatic food chains.

range of tolerance

The limits within which an organism can survive and function for a particular environmental factor, beyond which stress or death occurs.

sediment runoff

Soil and rock particles that wash into waterways from land, reducing water clarity and damaging aquatic habitats.

visual predators

Predators that rely on sight to locate and capture prey, which are hindered by reduced water clarity from sediment.

birth defects

Structural or functional abnormalities present at birth that result from developmental problems during pregnancy.

developmental disorders

Conditions that impair the normal physical, cognitive, or behavioral development of an organism.

endocrine disruptors

Chemical substances that interfere with the normal functioning of the endocrine system, disrupting hormone production and regulation in organisms.

endocrine system

The body system composed of glands and hormones that regulates growth, metabolism, reproduction, and other physiological processes in animals.

gender imbalances

Abnormal ratios of males to females in a population, often caused by disruption of sex determination or reproductive processes.

commercial development

A human activity that threatens wetlands and mangroves through land conversion for business and urban expansion.

dam construction

A human activity that threatens wetlands by altering water flow and hydrology.

ecosystem services

The benefits that humans receive from natural ecosystems, including resources, regulation of environmental processes, and cultural values.

flood protection

An ecosystem service provided by wetlands that reduces the impact of flooding events.

mangroves

Coastal ecosystems that provide ecosystem services and are threatened by human activities such as commercial development and overfishing.

overfishing

The removal of fish from aquatic systems at rates faster than populations can reproduce, leading to depletion of fish stocks.

pollutants

Harmful substances in the environment that are absorbed and filtered by forest trees.

water filtration

An ecosystem service provided by wetlands that removes particles and pollutants from water.

water purification

An ecosystem service provided by wetlands that removes contaminants and improves water quality.

wetlands

Areas where water covers the soil for at least part of the year, providing ecosystem services such as water purification and habitat.

agricultural runoff

Water flowing from agricultural land that carries fertilizers, pesticides, and other pollutants into aquatic ecosystems, contributing to eutrophication.

algal bloom

A rapid increase in algae population in a water body, typically caused by excess nutrients, which can deplete oxygen when the algae die and decompose.

anthropogenic causes

Environmental changes or substances caused by human activities, such as the release of CFCs into the atmosphere.

aquatic ecosystems

Water-based ecosystems including oceans, rivers, lakes, and wetlands that support diverse organisms and ecological processes.

detergents

Cleaning agents that contain phosphorus and other nutrients and can contribute to nutrient pollution in aquatic ecosystems when released into waterways.

dissolved oxygen

Oxygen gas dissolved in water that aquatic organisms require for respiration; levels decrease during eutrophication as microbes decompose dead algae.

eutrophication

The process by which a body of water becomes enriched with excessive nutrients, leading to algal blooms and oxygen depletion.

fertilizers

Substances added to soil to increase nutrient content for plant growth, which can cause water pollution and eutrophication when they run off into waterways.

hypoxic waterways

Bodies of water with low dissolved oxygen levels, often resulting from eutrophication and unable to support most aquatic life.

nutrients

Chemical elements or compounds, such as nitrogen and phosphorus, that promote the growth of plants and algae in aquatic environments.

oligotrophic waterways

Bodies of water with very low nutrient levels, stable algae populations, and high dissolved oxygen, representing the opposite condition of eutrophic waterways.