UNIT 8 APES

Point source pollution

Pollution that originates from a single, identifiable source, such as a factory's discharge pipe.

Non-point source pollution

Pollution that comes from multiple, diffuse sources, like runoff from agricultural fields.

Sedimentation in aquatic ecosystems

It can smother aquatic habitats, reduce light penetration, and disrupt photosynthesis.

Effects of oil spills on marine life

Oil spills can coat marine organisms, impairing their ability to move, breathe, and insulate themselves.

Endocrine disruptors

Chemicals that interfere with the endocrine system, potentially causing reproductive and developmental issues.

Example of an endocrine disruptor

Bisphenol A (BPA), commonly found in plastics.

Importance of wetlands

They act as natural water filters, provide habitat for wildlife, and protect against flooding.

Impact of human activity on mangroves

Activities like coastal development and aquaculture can lead to mangrove deforestation, reducing coastal protection and biodiversity.

Causes of eutrophication

Excess nutrients, particularly nitrogen and phosphorus, often from agricultural runoff or sewage.

Dead zone

An area in a body of water with extremely low oxygen levels, often caused by eutrophication, leading to marine life die-offs.

Thermal pollution

The degradation of water quality by any process that changes ambient water temperature, often from industrial discharges.

Effects of thermal pollution on aquatic organisms

It can decrease oxygen levels and alter reproductive cycles, leading to stress or death.

Persistent Organic Pollutants (POPs)

Toxic chemicals that resist degradation, bioaccumulate in organisms, and can travel long distances through the environment.

Example of a POP

Dichlorodiphenyltrichloroethane (DDT), a pesticide.

Bioaccumulation

The buildup of substances, like pesticides, in an organism over time.

Biomagnification

The increase in concentration of a substance in a food chain, affecting top predators the most.

Environmental concerns of landfills

Potential leachate contamination of groundwater and methane gas emissions.

Leachate

Contaminated liquid that drains from landfills, potentially polluting surrounding soil and water.

Composting

A method of waste disposal where organic waste decomposes naturally, turning into nutrient-rich soil.

Benefits of recycling

It reduces the need for raw material extraction, conserves energy, and decreases pollution.

Primary sewage treatment

Physical removal of large solids through screening and sedimentation.

Purpose of secondary sewage treatment

Biological processes that degrade organic matter using bacteria.

LD₅₀

The dose of a substance that is lethal to 50% of a test population.

Importance of LD₅₀ in toxicology

It helps assess the relative toxicity of substances.

Dose-response curve

It illustrates the relationship between the dose of a substance and its effects on an organism.

Threshold dose

The lowest dose at which a measurable effect occurs.

Steep dose-response curve indication

A small increase in dose causes a large effect, meaning the substance is highly toxic.

NOAEL (No-Observed-Adverse-Effect Level)

The highest dose at which no harmful effects are observed.

Determining toxicity of a substance

By conducting experiments to find LD₅₀ (lethal dose for 50% of a population) or ED₅₀ (effective dose for 50% of a population).

Acute exposure to pollutants

Short-term and high-dose exposure to pollutants.

Chronic exposure to pollutants

Long-term and low-dose exposure to pollutants.

Common sources of lead exposure

Old paint, contaminated water pipes, and industrial emissions.

Effects of particulate matter on human health

Respiratory issues, cardiovascular disease, and increased risk of lung cancer.

Pathogens in water supplies

They enter through sewage leaks, agricultural runoff, and contaminated drinking water sources.

Disease caused by water pollution

Cholera, caused by bacteria in contaminated water.

Climate change and human health

Increases heat-related illnesses, spreads vector-borne diseases, and worsens air quality.