Environmental Pollution and Waste Management: Key Concepts and Impacts

Point source

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

Nonpoint source

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

CAFO waste runoff

Point source pollutant example: animal waste containing ammonia and fecal coliform bacteria

BP Oil Spill

Point source pollutant example: hydrocarbons and benzene

Urban runoff

Nonpoint source pollutant example: motor oil, nitrate fertilizer, road salt, sediment

Range of tolerance

The range of abiotic conditions (pH, temp, salinity, nutrients) or pollutants an organism can survive

Acid rain effect on aquatic life

Decreased pH causes aluminum toxicity and disrupted blood osmolarity, leading to population decline

Indicator species

Species surveyed to determine ecosystem conditions (e.g., high whitemoss indicates pH < 6.0)

Coral reef human impacts

Warming ocean (bleaching), overfishing, sediment pollution, toxicants (sunscreen, oil), nutrient pollution

Oil spill physiological effects

Decreased photosynthesis, oil sticking to feathers, toxicity/suffocation of bottom-dwellers

Oil spill cleanup methods

Skimming, physical removal, chemical dispersants, burning

Endocrine disruptor

Chemical that interferes with the endocrine (hormonal) system of animals

Atrazine

Herbicide that binds to estrogen receptors in male frogs, causing feminization and low sperm count

DDT

Broad-spectrum insecticide that persists in environment and causes eggshell thinning in birds

Phthalates

Compounds in plastics and cosmetics that act as endocrine disruptors

Mercury

Heavy metal released from coal combustion; bacteria convert it to toxic methylmercury

Methylmercury

Highly toxic neurotoxicant formed from mercury by bacteria in water

Lead

Neurotoxicant and endocrine disruptor found in old paint, pipes, and coal fly ash

Arsenic

Carcinogenic and endocrine-disrupting element that can dissolve into groundwater from rocks or mining

Watershed

All land that drains into a specific body of water (river, lake, bay)

Chesapeake Bay threats

Nutrient pollution (eutrophication), endocrine disruptors, sediment pollution

Clearcutting effect on streams

Increased soil erosion, warmer water temperature, increased turbidity

Wetland

Area with soil submerged or saturated in water for at least part of the year, supporting emergent plants

Wetland ecosystem services

Water purification, flood protection, habitat, tourism, nutrient cycling

Mangrove threats

Commercial development, dam construction, overfishing, agricultural pollutants

Eutrophication

Excess nutrients (N and P) leading to algae bloom, hypoxia, and dead zones

Hypoxia

Low dissolved oxygen levels in water

Cultural eutrophication

Anthropogenic nutrient pollution from sewage, CAFO waste, and synthetic fertilizers

Dead zone

Area of water with hypoxia where most aquatic life cannot survive

Thermal pollution

Heat released into water producing negative effects on aquatic organisms

Warm water effect on DO

Warm water holds less dissolved oxygen than cold water

Cooling tower

Structure used to cool steam back into water before returning it to surface water

POPs

Persistent Organic Pollutants - synthetic, fat-soluble, long-lasting carbon-based compounds

Bioaccumulation

Absorption and concentration of fat-soluble compounds in an organism's tissues over time

Biomagnification

Increase in concentration of a substance per unit body tissue at higher trophic levels

DDT biomagnification effect

Eggshell thinning in predatory birds like eagles and osprey

PCBs

Industrial additives in paint/plastics that cause spawning failure and endocrine disruption

Solid waste

Any discarded material that is not a liquid or gas

MSW

Municipal Solid Waste - trash from cities, households, businesses

E-waste

Discarded electronics containing heavy metals like lead, mercury, cadmium

Sanitary landfill components

Bottom liner, stormwater collection, leachate collection, cap, methane collection

Landfill decomposition factors

Low oxygen, moisture, and organic matter slow decomposition

Incineration pros and cons

Reduces waste volume by 90% but releases CO2, PM, SOx, NOx, and toxic ash

Ocean dumping effect

Plastic garbage patches, entanglement, ingestion by wildlife

Reduce, Reuse, Recycle order

Reduce (most sustainable), Reuse, Recycle (least sustainable of the three)

Composting

Controlled decomposition of organic matter into fertilizer; reduces landfill methane

Composting drawbacks

Odor and attraction of rodents

Waste-to-energy

Burning waste to generate electricity; reduces landfill volume

Primary sewage treatment

Physical removal of large objects and settling of solid waste

Secondary sewage treatment

Biological process using bacteria to break down organic matter (aerobic)

Tertiary sewage treatment

Ecological or chemical processes to remove remaining pollutants (N, P, bacteria)

Disinfectant in sewage treatment

UV light, ozone, or chlorine used to kill bacteria and pathogens

Effluent

Liquid waste discharged from a wastewater treatment plant into surface water

Sludge

Inorganic solid waste that settles in treatment tanks

Combined sewer overflow

Heavy rains cause release of raw sewage into surface water

LD50

Dose of a chemical lethal to 50% of a population

Dose-response curve

Graph showing effect on organism or mortality based on toxin dose

ED50

Dose of a toxin causing a non-lethal effect (e.g., infertility) in 50% of population

Acute dose-response study

Short-term lab study measuring immediate effects of a toxin

Chronic dose-response study

Longer-term study measuring developmental impacts over time

Routes of exposure

Ways pollutants enter human body (ingestion, inhalation, absorption)

Synergism

Two or more substances interacting to cause an effect greater than the sum individually

Dysentery

Bacterial infection from sewage-contaminated food/water; causes severe diarrhea

Mesothelioma

Cancer caused by asbestos exposure, affecting respiratory tract lining

Tropospheric ozone effect

Worsens respiratory conditions, limits lung function, irritates eyes

Pathogen

Living organism (virus, bacteria, fungus, protist, worm) causing infectious disease

Vector

Living organism (rat, mosquito) that carries and transmits infectious pathogens

Plague

Bacterial infection transmitted by fleas on rats

Tuberculosis (TB)

Bacterial lung infection spread by respiratory droplets; leading infectious cause of death in developing world

Malaria

Parasitic protist infection from infected mosquito bites; common in sub-Saharan Africa

West Nile virus

Viral infection from infected mosquito bites; birds are main host

Zika virus

Viral infection from mosquitoes or sexual contact; causes birth defects (small brain)

SARS

Coronavirus pneumonia spread by inhaling or touching infected fluids

MERS

Viral respiratory illness transmitted from animals to humans

Cholera

Bacterial infection from drinking water contaminated with human feces