Midterm Flashcards
What sites might you encounter that require remediation?
- oil and gas leaks
- airports
- mining
- concrete production
- farmland
- agriculture, industrial , natural and commercial
What are some examples of contaminated sites
- has/service station
- mines
- agriculture
- pipelines
- Wells
- refineries
- tank farms (oil terminals) - storage facilities
Contaminated sites can impact
Soils, groundwater, surface water, biotics
What are the main types of contaminated sites that may be encountered by an environmental technologist
-agriculture —thermal facilities and incinerators -automotive repair and maintenance -dry cleaning -landfills -oil and gas -snow storage -nuclear
Describe the agriculture industry and how it can create contaminated sites
- involved in creating our food
- often overlooked as a source of contaminants
- fuels generally stored on site and can leak
- use of pesticides and fertilizers often used
Describe thermal facilities and incinerators and how it can create contaminated sites
Facilities that create heat, such as: coal fired power plants
- release coal by products
- ashes may contain a variety of materials
- materials used for cooling and lubricating the machinery
- facility itself may be contaminated
- surrounded area may be contaminated due to air emissions
Describe the automotive repair and maintenance and how it can create contaminated sites
Areas used for repairing automobiles
-lubricants
-paints
-solvents
-metals
-anti-freeze
-cfc’s
All these are on site and could be spilled or unintentionally released
Describe dry cleaning and how it can create contaminated sites
Process uses:
- non aqueous liquids
- when dry cleaning liquids get released into soil can infiltrate down down through soils and into ground water
- hot spot for contamination
Describe the landfills and how it can create contaminated sites
House/industrial waste is concentrated in landfills
- contains:cleaning products, batteries, paints, petroleum, pesticides organics ect
- rain/melting snow causes water to infiltrate through waste dissolving materials, this creates leachate
- uncontrolled leachate can contaminate gw
Describe the oil and gas and how it can create contaminated sites
Facilities (including exploration, production and retail) contain hazardous waste
- petroleum can be: g ie natural gas, l ie crude oil and s ie waxes
- petroleum is known to be hazardous to human and env health
- other sources of contamination: drilling muds, borehole cuttings, produced water and naturally occurring radioactive material
Describe snow storage and how it can create contaminated sites
(From street removal)
- can contain materials from road
- when snow melts the residue can contaminate soil @ location and surrounding areas from run off
Describe nuclear and how it can create contaminated sites
Generated from mining or uranium to use the nuclear material in the production of electricity
-highly toxic and long lasting making it an important concern
What are the potential contaminants of agriculture
Pesticides, metals (as components of pesticides), fuels
What are the potential contaminants of ash from incinerators or other thermal facilities
Metals, pH change, pah’s, pcb’s, dioxins/furans (depending on feedstocks), selenium
What are the potential contaminants of automotive repair, maintenance and auto body
Metals (aluminum, cadmium, chromium, lead, mercury), Voc’s, phc’s, btex, pah’s, acetone, carbon techrachloride, pce, tce, ethylene glycol, cfc’s, ph changeds
What are the potential contaminants of dry cleaning
Techrachloroethylene (or perchlorethylene (perc))and degradation products, some dry cleaners use hydrocarbon based materials
What are the potential contaminants of landfills
Metals(iron, mercury, lead, zinc), phc’s, betx, pah’s, voc’s (including phenols), cynide, pcb’s, pesticides, gases(including methane and co2)
What are the potential contaminants of machine maintenance shops, metal fabrication
Metals and voc’s
What are the potential contaminants of oil and gas -downstream (service stations, tank farms and card lots)
Phc’s, betx, voc’s, metals, pah’s, organic lead compounds, glycols, surfers, salts, pH change, naturally occurring radioactive materials
Norms
Naturally occurring radioactive materials
What are the potential contaminants of snow street removal
Metals, chloride sodium or sodicity
What is the reason that voc’s are Likely to be found on automotive repair and maintenance sites
Voc’s are in paints and solvents.
Why are oil and gas sites likely to contain norms?
They occur naturally in earths crust and in tissues of living things.
Produced water and petroleum often contain them and can form scales on tubing, equipment in sludge and as deposits inside pipelines
What does sodicity mean?
Sodic- non-saline soils where sufficient exchangeable sodium exists to adversely impact the soil structure and plant growth
Which types of oil and gas facilities might you find salts? Why?
Exploratory and production sites, but not retail sites.
Water is commonly produced with oil and gas and is separated at the surface. Brine contains high [] of dissolved salts and suspended solids.
-these materials are brought to surface where contamination could happen
Components of soil:
Mineral particles, organic matter,soil gas and soil vapour
What are mineral particles
A mixture of original parent material and particles of weathered parent material
What is the size of gravel?
> 2mm
What size is sand
0.05 to 2 mm
What size is silt
0.002 to 0.05 mm
What size is clay?
<0.002 mm
Are clay particles colloidal? What does that mean?
Yes, this means they have large surface area per unit of mass
Why is clay good for plants?
Many ions are attracted to the surface of clay particles (calcium, magnesium, sodium, potassium).
Plant roots in soils can contact these and absorb nutrients into plant.
-soils with a large proportion of fine particles cause water to infiltrate more slowly requiring plants to use less energy to remove water
-course easier then fine
Will remediation by soil flushing and vapour extraction be more or less efficient as the content of fine particles increases?
Less
What does soil organic matter include?
Carbon rich marterials from living and dead organisms. These are continually broken down by micro-organisms.
What % of soil is usually organic matter in well drained soil?
1-6%
How does soil organic matter influence remediation in soils?
Because physical and chemical interactions between organic chemicals and organic matter
What is organic matter?
It incorporates micro and macroscopic plants and animals. (Bacteria, fungi, algae, insects, worms, and even small mammals)
Can micro-organisms brodegrade petroleum?
Yes given enough time
Why is soil water important to organisms in subsurface and above ground
It contains hundreds of dissolved substances that can be used by organisms in the soil or taken up by plants.
What happens to gas content in pores when water content increases?
Goes down
How can contaminants affect soil?
They can be:
-absorbed to fine particles in soil(silt and especially clay)
- absorbed to carbon in soil
- dissolve in soil water
- contaminants in their vapour phase may fill pour spaces
What is the most direct method for remediation?
Excavation contaminated materials and transport to disposal site
What are some methods of soil remediation?
- excavation
- phytoremediation
- in situ thermal remediation
- chemical reactions
- biological reactions
- soil vapour extraction
What materials can affect gw
- non aqueous phase liquids (slightly soluble)
- LNAPL (can be trapped in pour space)
- DNAPL (can be trapped in pore space)
- metals
- voc’s
- pesticides
- pcb’s
Remediation techniques of gw
- contain contaminant and control mobility
- active treatment of contaminated water (either in situ or ex situ)
What are surface treatments methods of gw
- chem remediation
- biological remediation
- carbon absorption
- air stripping
What are some in situ methods for remediating gw
- air sparging
- thermal treatment
- permeable reactive barriers
- bioremediation
