Reference Library

Soilworks products are the industry’s top standard due to our insistence on creating high performance soil stabilization and dust control products that stand up to rigorous testing – both in the lab and in the field. Our commitment to quality and performance has led to our involvement and testing in hundreds of real-world situations. The following library of reports, presentations, specifications, approvals and other similar documents provide you, our customer, the transparency and dependable assurance that is expected from Soilworks.

Evaluation of Water Quality Impacts from Dust Suppressants (TPD1111004)

Objectives

  • Determine the water quality impacts of each dust suppressant in a simulated real world environment
  • Focus on products typically used in the desert Southwest
  • Focus on construction activity, as opposed to road or pile surface stability

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Table: Suppressants Selected for Study

Soil Selection Criteria

  • No visible contamination
  • Native land, no farming/industrial history
  • Normal soil range of metals
    • 6010 test for metals
    • 7471 test for Mercury

Soils Selected

  • Clark County AQMD and Maricopa County AQD recommended sample locations
    • Based on soil maps of each county
    • Maps classify soils by texture and dust-emitting potential
  • One Gallon Samples – 5 per county
  • Bulk Samples (five cubic yards) – 1 per county

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Map: Sampling Locations in Clark County

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Map: Sampling Locations in Maricopa County 

Soil Samples

  • One gallon samples taken by hand
    • Evaluate sensitivity of select water quality parameters to soil chemistry differences
  • Bulk samples taken by excavators
    • Pre-tests for metals contamination
    • Shipped to SDSU-SERL in super sacks

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Photo: One Gallon Samples

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Photo: Job Site/Heavy Equipment

Soil Processing

  • Sizeable rocks and debris removed
  • Performed sand, silt, and clay analysis
  • Thorough mixing at laboratory
  • Chain of custody procedures followed

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Graph and Table: Particle Size Distributions for Bulk Soils 

Test Protocol

  • Control Plots Treated with Reverse Osmosis Water Only
  • Surface Leaching (Runoff to Surface Waters)
    • Simulated rainfall (0.7, 1.3, and 2.4 inches/hour)
    • Simulated heating
    • Tested for general chemicals of concern
    • Tested for aquatic toxicity (fish, algae, and invertebrates)
  • Column Migration (Potential to Reach Groundwater – Subsurface Leaching)
    • Migration rate
    • Tested for general chemicals of concern

Sample Preparation

  • One of two reapplication/soil disturbance scenarios
    • A. Soil surface raked daily and product applied each day
    • B. Soil surface raked daily and product applied on days 1, 3, and 5
    • For synthetic products, B scenario was higher initial application and no reapplication
  • Duration for both scenarios is consecutive 5-day period following initial application
    • Each of 5 days, soil raked in alternating directions
    • Reapplication rates same as original application

Rainfall Events

  • 0.7 inches per hour for 150 minutes
  • 1.3 inches per hour for 80 minutes
  • 2.4 inches per hour for 43 minutes

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Photo: Runoff Collection from Test Tray 

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Photo: Runoff Collection/Soil Test Tray

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Schematic: Soil Bed Layout

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Photo: Tilting Bed SDSU-SERL

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Photo: Rain Heads SDSU-SERL

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Photo: Plan View of Tilting Soil Bed

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Schematic: Vertical Leaching Experiment

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Photo: Preparing Migration Test Cylinders

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Photo: Typical AZ (Left) and NV (Right) Soil Columns

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Table: Products Tested

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Table: Experimental Parameters

Analytical for Runoff and Leachate

  • Ph
  • Electrical Conductivity
  • TSS
  • TDS
  • DO
  • TOC
  • Nitrate and Nitrite
  • Total Phosphorous
  • Aquatic Toxicity (Runoff only)

Qualitative Analysis of Test Results

  • Surface Leaching Tests
    • All six products met study DQOs for pH, TDS, TOC, DO, and Nitrate
    • Most significant effect – High TSS in runoff from soils treated with Durasoil and EnviroKleen
    • AZ soil runoff typically had higher conductivity, TDS, TOC, nitrate, nitrite, and phosphate
    • NV soil runoff had higher pH and TSS
    • DO similar for both soils
  • Vertical Migration Tests
    • Water migration through a 12­inch column of soil
    • Average results by product for eight of nine parameters meet DQOs
    • TSS results varied but typically not a concern for groundwater quality
  • Pilot Tests
    • Evaluated soil/water/product mixtures
    • TDS for Enviro Roadmoisture 2.5 and Durasoil samples significantly higher than control samples – Not observed in runoff tests

Aquatic Toxicity Tests

  • Runoff samples for toxicity collected as part of SDSU’s surface leaching tests
  • Toxicity tests conducted by EPA Region 9 Lab
    • Fish (flathead minnow) – acute tests
    • Algae – chronic tests
    • Invertebrate (Daphnia Magna) – acute tests
  • Control samples based on RO water only

Aquatic Toxicity Testing

  • Fish Tests
    • No toxicity to fish observed in any runoff sample
  • Algae tests
    • No toxicity to algae observed in any runoff sample
    • Test may underestimate impact due to fine filtration of samples to remove sediments required by test protocol
  • Invertebrate Tests – Daphnia magna
    • For 4 surfactants, majority of samples showed no toxic effect relative to control samples
    • Adverse physical effect on daphnids for Envirokleen and Durasoil samples compared to control (Daphnids trapped on surface not able to re-enter water column).
    • Additional tests with smaller invertebrate (Ceriodaphnia Dubia) conducted on product samples of Envirokleen and Durasoil did not show physical entrapment effect.

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