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Field Studies Test #3


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organic matter
sources: sewage, ag runoff, industrial effluent
Plant nutrients
nitrates, phosphates
sources: ag runoff, acid deposition, sewage, detergents
Acid deposition
sources: air pollutants, acid mine drainage
Thermal pollution
sources: power plants
soil, silt, fine organic particles
sources: erosion, ag runoff, sewage runoff
bacteria, viruses, parasites
*most serious in terms of health effects*
Inorganic contaminants (non-metallic)
nitrates, flouride
Inorganic contaminants
mercury, lead, cadmium
sources: coal combustion, landfill incineration, mining
Organic chemicals
sources: pesticides/herbicides, plastics, pharmaceuticals, combustion products, disinfection products
Characteristics of point source pollution
- pollution discharged from a specific location
- discrete and identifiable
- easy to monitor and regulate
- tend to be fairly uniform throughout the year
- can "easily" divert or treat before it enters
- examples: factories, power plants, sewage treatment plants
Characteristics of non-point source pollution
- water pollution is scattered and diffuse
- no specific location where discharges into a particular water body
- tend to be fairly episodic
- more difficult to monitor, regulate, and treat
- examples: runoff from fields, stretts, roads, golf courses, lawns, gardens, and atmosphere
Clean Water Act of 1972
- directed at point sources
- required easily revoked permits for dumping pollutants into surface water
Two methods for approaching non-point sources of pollution
1) 1988 - assessed water quality through the EPA with a focus on watershed-level monitoring and protection
2) Riparian Zone management
riparian zone
zone of vegetation next to a water body, which acts as a buffer
Point sources of groundwater contamination
- underground storage tanks (gas, oil, petroleum)
- unplugged wells
- septic system (pathogens)
- industrial waste leaks (organic and inorganic chemicals)
- spills
Non-point sources of groundwater contamination
- mines -- drainage and dewatering (inorganic chemicals)
- ag (feedlots, fertilizer, erosion)
- landfill
- USTs -- if unknown source or wide-spread
- logging (soil erosion and nutrients)
- atmospheric deposition
- weathering rocks (inorganic chemicals)
- salt (natural rock and salt water)
- non-reactive solutes are transported by existing groundwater flow (liquid phase)
- move at same rat as groundwater
- no real change in concentration
- dilutes a contaminant and lowers its chemical concentration (liquid or dissolve phase)
- small-scale mixing in a porous medium
- caused by difference in velocity (geology and/or pores)
- contaminants that adhere to soil particles (particularly organic compounds)
- can slow the speed of contamination below the groundwater speed
- dissolved contaminants with higher concentrations migrate to lower concentrations (vapor & dissolved phases) regardless of groundwater flow
What is an LNAPL?
- Light Non-Aqueous Phase Liquid (floaters)
- do not dissolve in water
- float on top of capillary zone
- can be volatile --> vaporize
What controls LNAPL movement?
- follows slope of water table
- groundwater fluctuations --> spread contaminants
What is a DNAPL?
- Dense Non-Aqueous Phase Liquids (sinkers)
- do not mix well with water
- gravity pulls to bottom of aquifer
What controls DNAPL movement?
- follows slope of subsurface geology
- geologic barrier can slope in opposite direction of groundwater flow
What is MTBE?
- gasoline additive
- vaporizes easily, but is soluble in water
- moves rapidly in groundwater
Why is an understanding of food webs important to environmental science?
- helps you predict domino or ripple effects
What is bioaccumulation/biomagnification?
increase in concentration of toxins as you move up the food pyramid
Why is bioaccumulation/biomaginification of concern to humans?
- fat soluble contaminants are very persistent
- organisms at one trophic level feed on lots of individuals at lower trophic levels
What is a keystone species?
- despite low biomass, exert strong effects on the community that they inhabit
- typically this is because of the role they play in the food web
the study of the nature and mechanism of toxic effects of substances on living organisms and other biological systems
What are the major hazards that shorten the average lifespans of people in the US?
- poverty (7-10 yrs)
- born male (7.5 yrs)
- smoking (6 yrs)
- overweight (6 yrs)
- unmarried (5 yrs)
Major steps in risk assessment
1) what is a hazard?
2) what is the probability of its occurrence?
3) assess the severity of its health, environmental, economic and social impact
Major steps in risk management
1) how does this risk compare with others?
2) how much should we reduce it?
3) how will we reduce it?
4) how much will it cost?
Why is toxicology such a difficult science?
it is difficult to categorize and assess hazards
What is the current trend in cancer among both adults and children?
- total incidence of cancer is up in recent years, but death rates are down (better treatment)
- childhood cancers: average annual increase of between 1% and 3%
What explains the current trend in cancer?
- cigarettes
- bad diets
- more environmental pollutants
- family history/genetics
What determines if a chemical is harmful?
1) dose (how much)
2) response (type/amount of health damage)
What are immune system responses to environmental contaminants?
- hypersensitive immune response --> fast allergic response
- suppressed immune response --> compromise immune system function
What are neural system responses to environmental contaminants?
- fast and devastating responses, e.g.: learning disabilities, problems with movement, death
What are endocrine system responses to environemntal contaminants?
- endocrine disrupters: slow down production of hormones
- hormone mimics: speed up rpoduction of hormones
What are the steps of drinking water treatment and what contaminants are removed with each step?
1) 1/4 in. screen
- remove large physical contaminants
2) chlorine disinfection
- strong oxidizing agent, kills pathogens
3) coagulent mixing
- form a sticky gel to remove suspended particles
4) stirring/floculation
5) settling
6) filtering
- anthrocite coal to remove dissolved organics
- sand to remove remaining particles
7) addition of sodium flouride
- good for teeth
8) additional blast of chlorine
- kill any remaining pathogens
What is the primary goal of drinking water treatment?
removal of pathogens
What is the primary goal of sewage treatment?
lower BOD, followed by removal of pathogens
What does groundwater remediation mean to clients?
- cost
- regulations
- closure
What does groundwater remediation mean to regulatory people?
- protect groundwater
- proactive
- closure
- permitting
What does groundwater remediation mean to consultants?
- make both happy
- prevent technology
- cost effective and works
- simple
- closure
Examples of pump and treat technique for groundwater remediation
- water treatment
- examples: air stripping
Examples of vapor treatment technique for groundwater remediation
- vapor phase treatment
- examples: vapor extraction and air sparging
Examples of in situ technique for groundwater remediation
- treat both water and vapor phases inside aquifer
- examples: chemical oxidation, phytoremediation, bioremediation, and vitrification
Examples of excavation technique for groundwater treatment
- physically remove contaminants by digging (soil)
- examples: solvent extraction, soil washing, incineration, thermal desorption, and chemical dehalogenation
Advantages and disadvantages of air stripping
- good for large contaminant plumes
- easy to operate
- minimal space
- treat gas from stripping towers
Advantages and disadvantages of air sparging and vapor extraction
- easy to construct and operate
- minimal disruption
- does not control groundwater
- can cause groundwater mounting
Advantages and disadvantages of in situ treatment
- minimal distruption
- can do under buildings
- requires complete understanding of contaminants, concentrations
- requires permeable materials and knowing the geology
Advantages and disadvantages of excavation
- immediate source removal
- good where can't use other techniques
- may be expensive
- disruption
- slow business
- may not address groundwater contamination
What is the history of the Congress Gas and Oil site?
- contamination discovered in 1988
- 1988-1994: removal of UST, soil vapor extraction, pump and treat
- 1994-1998: new company - soil vapor extraction replaced with air stripper, found deeper gas contamination
- 2000: new company - electrochemical peroxidation, 5 new recovery wells, contamination is contained
the use of living organisms to help in the remediation of polluted sites
2 major ways organisms clean up contaminants
1) break it down: contaminant serves as organism's food source
2) absorb it
Advantages of bioremediation
- many applications (increasingly find it's cheaper than low-end remediation techniques)
- doesn't rely on heavy equipment that produces air pollution problems
- can be less environmentally intrusive
- often more effective than conventional methods
- can reduce the amount of material dumped in landfills
Disadvantages of bioremediation
- can be a slow(er) process
- may take repeated "plantings"
- sometimes only effective to root depth
- insects may feed off of contaminated leaves
- sometimes have to add extra stuff --> nitrogen and phosphorous
- introduced species issues
Advantages for using a living machine for treatment of industrial waste or sewage, especially in developing countries
- less waste
- more efficient
- more ecosystem friendly
- cheaper once implemented
What are major concerns about soils?
1) nutrients (loss of)
2) soil erosion (loss of topsoil)
3) soil contamination (contaminatns stay in soil longer than water)
4) soil strength (leaning tower of Pisa!)
residual soil
soil forms on top of bedrock
transported soil
sediments deposited by other means (river, wind, glaciers, volcanoes)
soil profile (horizons)
O = organic - leaves, sticks, organics (dark brown to black)
A = minerals, organics (brown)
E = little to no organics, mostly minerals (white to grey)
B = salts, clays, carbonates, gypsum (very red)
C = fresh parent material
R = rock

zone of leaching = A, E
zone of accumulation = B
what does soil development depend on?
1) climate (how wet and warm)
2) time
3) parent material
4) topography
5) biological activity
definition of soil
dynamic system composed of:
1) weathered rock/minerals
2) detritus (organic litter)
3) soil organisms (feed on detritus)
feedback loop between soil development and plant communities
plants develop soil, soil is necessary for plants to live
changes in soil and communities over successional stages
1) lichens - unique acids - etch rock
2) mosses - start to get organic matter
3) plants - roots - store H20, aerate soil, stabilize soil (prevent erosion), buffer (absorb nutrients)
how do impervious surfaces affect flood magnitudes?
impervious surfaces increase the frequency of small floods because channels were not designed by nature to handle excess water
how does urbanization affect water quality?
1) add nutrients (lawns, golf, farms, golf courses, septic systems, pet poop)
2) add other pollutants (tire residue, sediment, salt)
3) industrial pollution (heavy metals, chemicals/solvents, thermal pollution)
how does urbanization affect groundwater?
1) impervious surfaces = lower infiltration capacity = slower recharge
2) more houses = more wells = more H2O
3) lower groundwater table = effect surface H2O
how does the size of the watershed fit into urbanization affects?
1) urbanization is less of a problem with larger watersheds
2) cumulative effects exasperate the problem for large watersheds
3) more political units = more difficult to regulate
Why do we build dams?
** #1 -> recreation **
- reservoirs
- flood prevention
- power (electricity)
- irrigation
What are the major biological impacts of dams?
- prevent fish migration
- increase sedimentation (habitat destruction)
- increase turbidity (suffocate fish, lower visibility)
- reduce DO and increase temp
- destroy wetlands and terrestrial habitats
- hinder agriculture productivity
What are the major environmental impacts of rural to urban migration?
loss of biodiversity
What are the largest contributors to the loss of biodiversity today?
1) habitat losses
2) exploitation
3) introduction of exotic species
What factors influence the equilibrium of species richness that we see in the "islands" of remaining habitat?
1) size
- bigger islands have higher equilibriums because immigration is easier and extinction is less likely
2) distance to mainland
- closer islands have higher equilibrium because immigration is easier, and recolonization is easier, meaning extinction is less likely
What are the other biological and environmental impacts of habitat fragmentation and urbanization?
- fragmentation leads to edge effects like blowdowns, increased temperatures, decreased moisture, and increased light
- change in species composition -> gives certain species a real competitive edge
- increased car traffic
- increased roadways (increases surface water, possibility for pollutants, and roadkill)
- warmer microclimates in urban environments
What are the factors that influence the allocation, use and conservation of water?
- people along riverbanks have the right to use as much water as they like, as long as they don't interfere with the quality or quantity downstream
(founded on the principle that there's an endless supply of water, and it only has value when we use it)
- use water or lose it, it's founded on economics
- low pricing is a factor contributing to how much we use it
- privitazation vs. non privatization plays a key role
What are some of the major agencies involved in water rights and how do their missions vary?
- US Geologic Survey, National Park Service, Army Corp of Engineers -> mission = controlling water and making it accessible
- EPA and US Fish/Wildlife Service (after WWII and environmental disasters) -> mission = focus on conservation rather than stewardship
What are the major concerns with the privatization of water?
- loss of public control of water resources
- loss of potential for community
- loss of small scale water and sewage treatment
- once a country starts exploiting water, they can be stuck exploiting water
- commodification of water has led to lower quality and higher consumer price
What are the major methods of water conservation?
1) work on economics of water -> charge directly/fully for water
2) make corporations, individuals pay for cleanup
3) improve water efficiencies (infrastructure)
4) use of drip irrigation
5) industry technology (composting toilets, recapturing/reusing waste water)

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