Pollutants Flashcards
(41 cards)
What is the difference between a toxicant and a toxin?
toxicant = synthesized (manmade) toxic chemicals
toxins = harmful substances produced biologically (i.e biotoxins, HABs)
How can risk be determined (i.e ___ x ____)?
exposure x toxicity
What are some factors behind a pollutant’s risk?
- chemical activity
- dose
- exposure route
- ability to be absorbed
- species exposed
- age of individual exposed
- metabolism of exposed
- excretion rate
- interactions with other chemicals
What are some sources of contaminants?
- runoff (road and agricultural)
- shipping leakage
- wastewater
- disposal at sea
- agriculture
What are some examples of contaminants?
- oil
- POPs (persistent organic pollutants)
- metals
What are some sources of oil?
- natural leakage
- marine transportation
- runoff from land
- air pollution
- jettisoned fuel
- offshore oil extraction
What are the steps of contamination from an oil spill?
- spreading along the surface of the water
- partial evaporation into the atmosphere
- dissolving into deeper water
- emulsifying from water movement
- dispersion of smaller oil particles
- biodegradation from microorganisms
- breakdown from photo-oxidation
- adsorption
- sinking/sedimentation
What animals were most acutely affected by the Exxon Valdez oil spill?
- seabirds (largest # impacted)
- killer whales
- marine mammals (otters, seals)
What long term effects did the Exxon Valdez spill have on ecosystems?
- loss of some algae species (primary producers)
- loss of some herbivorous gastropods (primary consumers)
- loss of some carnivorous gastropods (secondary consumers)
- increase in some barnacles (primary consumers)
What effects did the Deepwater Horizon spill have on ecosystems?
- affected 2000km of wetlands
- negatively affected mussel recruitment for several years
- large mortality of seabirds, dolphins and sea turtles
What are POPs?
- persistent organic pollutants
- bioaccumulative (lipophilic = can store easily inside cells)
- can be transported far from origin via atmospheric movement
- strong health concerns for both humans and environment
Name two examples of POPs and desribe them
DDT
- pesticide (insecticide)
- metabolized form DDE can cause eggshells to thin out
- banned use
PCB
- found in transformer fluids
- heat resistant
- carcinogenic/immunotoxic
In which marine organism are PCBs the most concentrated?
Biggs and SR killer whales
What pollutant is found in marine mammal’s milk?
POPs
How do POPs affect wildlife?
- altered behaviour
- impairs reproduction
- can cause deformities/birth defects
- endocrine disruption
- can affect immune system
What three metals are prevalent in marine pollution and where are they found?
cadmium
- byproduct from zinc mining
- found in batteries, paints, cigarettes, fertilizers
mercury
- found in mining, coal combustion, batteries, older medical instruments
lead
- found in some gases, alloys, paints and ammunition
Which metal has a high risk of bioaccumulation in the arctic?
mercury
What is 6PPD-quinone?
- additive in car tires to make them stronger against wear
- ozonation releases chemical
- rain can transport chemical via runoff and reach aquatic ecosystems
- responsible for mortalities of coho salmon
How did mercury affect the animals and residents of Minamata, Japan?
- inorganic mercury was released from a chemical processing plant into the bay
- mercury binded with carbon to become methylmercury
- methylmercury bioaccumulated in plants and fish before being consumed by cats and humans
- caused uncontrollable spasms, numbness, loss of some senses and death
Define eutrophication/nutrient enrichment
- increase in primary productivity and organic matter accumulation
- caused by increased concentrations of limiting nutrients like N and P
- can cause excess growth of algae/phytoplankton
- can increase turbidity and create hypoxic conditions
Which nutrient makes up the bulk of global fertilizers?
nitrogen
What region of the world uses the most fertilizer?
Asia
Where can some deadzones be found?
- Gulf of Mexico/SE coast of USA
- western Europe
- Japan/Korea coast
Why does the Gulf of Mexico have strong dead zones?
- runoff from Mississippi river (drains 40% of USA’s agricultural land) deposits fertilized nutrients into the water
- bacteria consume nutrients and depletes water of oxygen at lower depths
