CGM Remediation & Mitigation Strategies 3 — Questions and Answers
Question 1: Phytoremediation using sunflowers (Helianthus annuus) is particularly effective for which soil contaminant?
- Petroleum hydrocarbons
- Heavy metals including lead and uranium (Correct answer)
- Chlorinated solvents
- Nitrate compounds
Correct answer: Heavy metals including lead and uranium
Sunflowers are hyperaccumulators proven effective at extracting heavy metals such as lead, cesium, and uranium from contaminated soils.
Question 2: What is the purpose of a 'French drain' as a site mitigation strategy?
- To filter chemical contaminants from runoff
- To redirect subsurface water away from problem areas (Correct answer)
- To inject amendments into deep soil layers
- To collect surface runoff for irrigation reuse
Correct answer: To redirect subsurface water away from problem areas
A French drain uses a perforated pipe in a gravel-filled trench to intercept and redirect subsurface water, mitigating waterlogging and drainage problems.
Question 3: A grounds manager is tasked with remediating a pesticide spill on turf. Which action should be taken FIRST?
- Apply activated charcoal to the affected area
- Contain the spill to prevent further spread (Correct answer)
- Collect soil samples for laboratory analysis
- Notify the state environmental agency
Correct answer: Contain the spill to prevent further spread
Containing the spill immediately prevents further environmental spread and limits the total area requiring remediation.
Question 4: Which soil amendment is most commonly used to immobilize heavy metal contaminants through pH adjustment?
- Sulfur
- Agricultural lime (Correct answer)
- Ammonium sulfate
- Iron sulfate
Correct answer: Agricultural lime
Agricultural lime raises soil pH, causing many heavy metals to precipitate into less soluble, less bioavailable forms in the soil matrix.
Question 5: What is 'in-situ chemical oxidation' (ISCO) used for in site remediation?
- Reducing soil acidity through chemical neutralization
- Injecting oxidants into soil or groundwater to destroy organic contaminants (Correct answer)
- Oxidizing excess nitrogen to prevent runoff
- Applying chemicals to oxidize invasive plant root systems
Correct answer: Injecting oxidants into soil or groundwater to destroy organic contaminants
ISCO involves injecting powerful oxidants such as permanganate or persulfate directly into contaminated zones to chemically destroy organic contaminants.
Question 6: A rain garden designed for stormwater mitigation performs best when planted with which type of vegetation?
- Shallow-rooted annual flowers
- Deep-rooted native plants tolerant of both wet and dry conditions (Correct answer)
- Dense turfgrass
- Shade-tolerant ferns
Correct answer: Deep-rooted native plants tolerant of both wet and dry conditions
Deep-rooted native plants improve infiltration, tolerate periodic flooding and drought cycles, and require minimal maintenance in rain garden applications.
Question 7: Which erosion control practice is most appropriate for stabilizing a freshly graded slope within 24 hours of a predicted storm?
- Seeding with a native grass mixture
- Applying erosion control blanket or hydraulic mulch (Correct answer)
- Installing riprap at the slope base
- Broadcasting compost over the surface
Correct answer: Applying erosion control blanket or hydraulic mulch
Erosion control blankets or hydraulic mulch (hydroseeding tackifier) provide immediate surface protection against raindrop impact and runoff before vegetation establishes.
CGM Remediation & Mitigation Strategies 3
Phytoremediation using sunflowers (Helianthus annuus) is particularly effective for which soil contaminant?