c9: u7/u8 pollution

toxicity and health

• toxin: substance that when inhaled, ingested, or absorbed, damages a living organism

  • toxicity is degree to which it is harmful

  • toxicity is tested using a dose-response analysis—organisms are exposed to a toxin at different concentrations to see what kills it

  • this information is graphed to form a dose-response curve

  • LD50: dosage of toxin to kill 50 percent of tests

    • poison has an LD50 of 50mg or less per body weight

• FDA regulates certain toxins through the Delaney Clause, which specifically bans any food additives found to cause cancer in humans or in animal testing

• ED50: point at which 50% of test organisms show negative effect from toxin

• acute effects are short exposures to high levels of toxin like snake venom, chronic is long-term exposure

• infection comes from pathogens invading the body

  • pathogens can be viruses, bacteria, fungi, protozoa, or worms and spread through carriers (vectors) or unsanitary conditions

• different pathogens

  • plague—disease carried by organisms affected by plague

  • tuberculosis—lung attack

  • cholera—infected water from poverty and sanitation

  • dysentery—inflamed stomach from bacteria and worms

  • malaria, west nile, zika—bites from mosquitoes

  • severe acute respiratory syndrome is viral respiratory disease, one of its branches is covid-19

• pollutants: any substance that renders air, soil, water, or another natural resource harmful

air pollution

• can be human-caused or naturally from the environment

• primary pollutants are released directly into the lower atmosphere, secondary pollutants are formed by the combination of primary pollutants in the atmosphere

• stationary (factory ex.) vs nonstationary (car), point source pollution (specific place of pollution comes from) vs non-point source

• 6 main culprits:

  • carbon monoxide (CO) can inhibit us from getting oxygen if we are around too much of it

  • lead can cause nervous system disorders and comes from industrial smelting oftentimes

  • ozone

    • stratospheric ozone absorbs harmful lights from the sun to protect us, while tropospheric ozone is a respiratory irritant

    • O3 can form as a secondary pollutant

  • nitrogen dioxide is a component of smog and acid rain

  • sulfur dioxide comes from burning coal and fossil fuels, creates acid rain

  • particulate matter is irritating particles we breathe in

• clean air act: aims to reduce pollution

• volatile organic compounds: released because of industrial processes and create smog

• smog:

  • comes from pollutants that are associated with burning oil or coal

  • brown smog (photochemical smog) is formed on hot, sunny days in urban areas and causes breathing problems, while gray smog is from industrial production

  • equations pg 253

• acid precipitation

  • chart pg 253

  • caused when gases combine with water to form acids as a result of pollution

  • dry acid particle deposition occurs 2-3 days after emission into the atmosphere, wet deposition is 4-14

• motor vehicles and air pollution:

  • catalytic converters in cats help reduce air pollution and so do vapor recovery nozzles

  • corporate average fuel economy reduces fuel consumption and emission through burning less gas

• indoor air pollution:

  • indoor air pollution is a major risk because many people work inside all day with little to no ventilation

  • tobacco smoke and radon can both cause lung cancer through indoor pollution, as can dust, asbestos (mineral that ppl used to build but wasn’t good for us), formaldehyde, and lead

  • sick building syndrome (SBS) is when the majority of a building’s occupants experience certain symptoms which is SO SAD

thermal pollution

• heat islands: urban areas (because urban areas are warmer from concrete, etc. that absorbs heat more)

• this problem can be fixed with trees/green spaces, adding greenery to roofs (pg 258)

• temperature inversion: occurs when air pollutants become trapped over cities and cannot rise into the atmosphere (pg 258/259)

water pollution

• clean water act of 1972—governs water pollution, water quality, and water uses

  • reduced direct pollutant discharges into waterways

  • financed wastewater treatment facilities

  • helped restore and maintain water

• safe drinking water act—monitored and increased safety of drinking water

• water pollution’s main problem is that runoff from land carries excess nutrients and pollutants to streams, which eventually can flow into the ocean (often depicted through an oxygen sag curve)

• eutrophication can occur when freshwater that has waste/pollution in it mixes with sea water, creating an algal bloom that prevents anything from growing there

• water than is stagnant, like in ponds, often takes a bunch of time to recover from pollution if at all

• water pollution can be dealt with by reducing/removing sources of pollutant or treating the water to remove pollutants or render them harmless in some way

• major water pollutants:

  • excess nutrients, organic waste, toxic waste (like acid mine drainage), sediments, etc.

  • persistent organic pollutants are compounds that do not degrade over time, often endocrine disruptors meaning they interfere with the endocrine systems of animals

• biomagnification: term describing how toxic molecules are more highly concentrated higher up the food chain (pg 264)

• how to judge water quality?

  • pH—acidic?

  • hardness—too much calcium?

  • dissolved oxygen—low levels indicate an inability to sustain life (warm water holds less dissolved oxygen than cool water)

  • turbidity—density

  • BOD (biological oxygen demand) which measures the rate bacteria absorb oxygen from the water

• wastewater: water that is human waste can be very dangerous, here is the process to reuse it:

  • filtered through screens first (physical treatment) to get out large objects

  • primary treatment—chemicals to help suspended solids settle out as sludge

  • secondary treatment—biologically treating the wastewater, often by pumping it through a sludge processor

  • tertiary treatment (optional) is when wastewater goes into groundwater but needs another chlorinating pass

solid waste (garbage)

• solid waste=any discarded material that is not a liquid or gas

• reduce reuse recycle!!

• primary recycling—materials such as plastic are used to rebuild the same product

• secondary recycling—forming new products that are lower quality goods

• composting—using organic matter, decomposing it and putting it into the soil

• landfills

  • sanitary landfills have federal regulations for where they can be placed, waste in landfill must be frequently covered with soil to control insects, bacteria, odor, etc.

  • decomposed material that goes to the bottom of the landfill (leachate) is piped to the top of the site and collected in lechate ponds

  • waste that is dumped in the ocean creates large piles of trash!!

  • waste can be burned to create energy (waste to energy program)

hazardous waste (batteries, paints, etc.)

• not really tested on so idk why there’s a section for it?

• corrosive waste= corrodes metal; ignitable=makes fire, reactive=makes boom, toxic waste=rly bad for you, transuranic waste=waste left after nuclear weapons are made

• high level radioactive waste=high levels of radiation, low level radioactive=self explanatory

• surface impoundment is used to get liquid waste out by creating shallow pools where the liquid evaporates

• deep well means drilling a rly deep hole to get rid of it

• superfund program created to hold people accountable for disposing of hazardous waste

• 1976—resource conservation and recovery act helped develop plans to gt rid of waste and hazardous waste

• 1980—comprehensive environmental response act created a tax on chemical industries and helped regulated closed hazardous sites

noise pollution

• US noise control act gave the EPA power to set emission standards for major sources of noise

• noise pollution can damage hearing and affect ecosystems