Chapter 5 - Part II Flashcards
Prior to the 1940s, what were the metals commonly found in pesticides?
- arsenic
- mercury
- copper
- lead
What are the current replacements for metals in pesticides?
- organophosphorus compounds (malathion & diazinon)
- carbamates
In 2001, this was the most common pesticide detected in drinking water.
Atrazine
Atrazine was banned in the EU in what year?
2004
How is Atrazine toxic to the environment?
- degrades slowly in groundwater
- primarily nitrogen source for microbes
- carcinogen
What is the pesticide that degrades via hydrolysis, biodegradation, and photolysis?
Malathion
How is Malathion toxic to the environment?
- found in surface waters
- rapidly absorbed, biotransformed, and excreted if ingested
What is the biotransfored compound that can form from Malathion?
succinate
How is DDT transformed into DDE and DDD?
-HCl
H2 -> HCL
What properties of DDT make it easily transported through the environment?
- hydrophobic
- persistent
What are some industrial contaminants?
- petroleum hydrocarbons
- perchlorate
- heavy metals
- PCBs
- Bisphenol A
What is the process of oil’s fate as it travels through aquatic environments?
1) physical transport
2) dissolution
3) evaporation
4) emulsification
5) oxidation and destruction
6) sedimentation
7) microbial degradation
What do effluents contain?
- ammonia
- sulfides
- phenol
- hydrocarbons
- heavy metals
What do oil refineries produce?
crude oil
contains BTEX
What are some treatments for effluents?
- flocculation
- sedimentation
- activated sludge
What do effluents have that makes them more toxic and persistent than crude oil?
polycyclic aromatics
What is found in rocket fuels, explosives, and some fertilizers?
perchlorate
Why is perchlorate so toxic to the environment?
- dissolve easily and infiltrate ground water
- can accumulate in crops
- persistent with high activation energy
What is another form of perchlorate?
ammonium perchlorate
What part of the body is most affected by perchlorate?
thyroid
What river system has been found to be contaminated by perchlorate?
the Colorado River
What is the bioremediation process for perchlorate?
perchlorate -> chlorate -> chlorite -> chloride
Name the toxin
- banned in the US in 1979
- banned at Stockholm convention in 2001
- structurally similar to dioxins
polychlorinated biphenyls (PCBs)
Why is PCBs toxic to the environment?
- carcinogen & endocrine disruptor
- still present in landfills and degrade slowly
- microbial detoxification through reductive dechlorination or dioxygenase enzymes
What are some examples of heavy metals?
- Cadmium (Cd2+)
- Mercury (Hg2+)
- Lead (Pb2+)
- Argon (ArO2-)
What do bacteria and fungi efficiently transform metals in to?
micronutrients
Through what processes do bacteria and fungi transform heavy metals?
- ligand exchange
- oxidation
- reduction
What is this?
- makes polycarbonate (PC)
- plastics
- epoxy resins
- pesticides
Bisphenol A-BPA
What is the acute toxicity of Bisphenol A-BPA?
1-10 microgram/mL
What are the adverse effects of Bisphenol A-BPA on the body?
endocrine distruptor and xenoestrogen
What are the major metabolites of Bisphenol A-BPA?
- BPA glucuronide
- BPA sulfate
How many pharmaceutically active compounds are present and used in medicine?
3000
Where is one place where antibiotics and hormones can come from?
livestock
Mixture of organic matter and inorganic matters (silica, clay water and air)
soil
Chemicals can move in a medium and undergo ____ reactions, also transported to plant and animal life.
chemical
What is an intentional addition of chemicals to the soil?
What is and uninentional additions of chemicals to the soil?
intentional: fertilizer/pesticides
unintentional: chemical leaks/spills
The more the solution concentration, the ____ the pH
higher
With increase of the pH, at different concentrations, there will be a ____ to cross where it will become more soluble.
threshold
There is a difference in the structure of chlorines. When a chlorine is removed, the sorbed concentration ____.
lowers
Some basic components of soil tend to have a ____ line to it on a graph showing a gradual and high volume of sorption. Acidic components of soil tend to have a short, ____ line.
curved; straight
Chemicals can be absorbed through the what parts of aquatic animals?
- lungs
- skin
- gills
In the biosphere, direct absorption from environmental medium can result in ____ or ____.
- bioaccumulation
- bioconcentration
the portion present within a medium this is potentially available for direct uptake by the organism.
bioavailability
High bioavailability leads to…
- bioaccumulation in organisms
- migration through food chains
- biotransformation
Lipophilic and environmentally persistent chemicals such as DDT can be stored and accumulated in fatty tissue compartments.
bioconcentration
equal to the concentration of the pollutant in an organism divided by its concentration in the water or environmental matrix.
bioconcentration factor (BCF)
How us the bioconcentration factor (BCF) calculated?
Calculated from ratio of the toxicant concentration in the whole animal at steady state, to its concentration in its environment.
What are the steps which an external exposure must take to reach it’s target?
beginning in the soil
soil > ingestion > dissolution > absorption > reduction > target
What factors affect a popultion growth positively and which affect it negatively?
positively: natality, immigration
negatively: emigration/mortality
study
mild: resistent individuals, minimal effect
response to same dose: majority, average
severe: sensitive individuals, maximal effect
