Pollution Flashcards
Toxicity
The degree to which a toxin is biologically harmful
Dose-response analysis
Used to test toxicity of a substance
Organisms are exposed to a toxin at different concentrations, and the dosage that causes the death of the organism is recorded. The information from a set of organisms is graphed, and the resulting curve is referred to as a dose-response curve.
LD50
The dosage of toxin it takes to kill 50 percent of the test animals in a dose-response analysis.
Poison
Any substance that has an LD50 of 50 my or less per kg of body weight
ED50
The point at which 50 percent of the test organisms show a negative effect from a toxin
Threshold dose
The dosage at which a negative effect occurs
Acute effect
An effect caused by a short exposure to a high level of toxin; e.g. a snakebite
Chronic effect
What results from long-term exposure to low levels of toxin; e.g. Long term exposure to lead paint in a house
Infection
The result of a pathogen invading our body
Disease
Occurs when an infection causes a change in the state of health
5 main categories of pathogens
Viruses (and other sub cellular infectious particles, such as prions) Bacteria Fungi Protozoa Parasitic worms
How do Pathogens attack
Can attack directly or via a carrier organism (called a vector)
Primary pollutants
Those that are released directly into the lower atmosphere (troposphere) and are toxic
Ex. Carbon monoxide
Secondary pollutants
Those that are formed by the combination of primary pollutants in the atmosphere
Ex. Acid rain
The six criteria pollutants
Carbon monoxide Lead Ozone Nitrogen dioxide Sulfur dioxide Particulates
Carbon Monoxide (CO)
An odorless, colorless gas that’s typically released as a by-product of incompletely burned organic material, such as fossil fuels. It is hazardous to human health because it binds irreversibly to hemoglobin in the blood. More than 60% comes from vehicles that burn fossil fuels
Tropospheric ozone
Powerful respiratory irritant and precursor to secondary air pollutants
How is O3 (the secondary pollutant) formed in the troposphere
The result of the interaction of nitrogen oxides, heat, sunlight, and volatile organic compounds (VOCs)
Effects of acid precipitation (8)
Leaching of some minerals from soil (which alters soil chemistry)
Creating a buildup of sulfur and nitrogen ions in soil
Increasing the aluminum concentration in soil to levels that are toxic for plants
Leaching calcium ions from the needles of conifers
Elevating the aluminum concentration in lakes to levels that are toxic to fish
Lowering the pH of streams, rivers, ponds, and lakes, which may lead to fish kills
Causing human respiratory irritation
Damaging all types of rocks, including statues, monuments, and buildings
Stratospheric ozone
Absorbs UV light from the sun and therefore protects life on our planet
Eutrophication
When warm, nutrient-rich freshwater runoff travels into a body of cold seawater, which allows phytoplankton to grow uncontrollably, zooplankton that feed on them to experience population explosion. When they die, bacteria metabolize the available dissolved oxygen as they decompose this detritus, resulting in a lack of dissolved oxygen in a hypoxic zone.
Clean water act of 1972
Used regulatory and non regulatory tools to protect all surface waters in the United States
Sharply reduced direct pollutant discharges into waterways
Financed municipal wastewater treatment facilities, and manages polluted runoff
Achieved the broader goal of restoring and maintaining the chemical, physical, and biological integrity of the nation’s waters
Supported “the protection and propagation of fish, shellfish, and wildlife, and recreation in and on the water”
Ocean dumping act of 1972
Made it unlawful for any person to dump, or transport for the purpose of dumping, sewage, sludge, or industrial waste into ocean waters
Safe drinking water act of 1974, 1996
Established a federal program to monitor and increase the safety of the drinking water supply. It does not apply to wells that support fewer than 25 people