The Armour Road site was used for railroad herbicide manufacturing and blending from 1948 to 1986. Powdered arsenic (95% pure), monosodium arsenic, and various other chemicals were part of the herbicide production. Subsurface testing showed significant arsenic contamination in over 40,000 tons of soil. The EnviroBlend® team formulated a site-specific treatment chemistry for the contaminated soil that was effective at low doses, saving the owner considerable off-site disposal costs.
Soil Arsenic Concentration, mg/kg EnviroBlend(R) Dosage, weight %
<2,000 1.15
2,000-5,000 1.75
5,000-15,000 2.3
Approximately 11,000 cubic yards of soil were initially treated at dosages ranging from 0.75 to 2.3 percent by weight. Table 1 provides a summary of full-scale treatability data on the initial soil stockpiles.
| Table 1. Initial Full-scale Treatability Data Summary | ||||
|
Pre Treatment |
Post Treatment |
|||
|
Dose |
Total Arsenic |
TCLP Arsenic |
TCLP Arsenic |
|
|
Range |
0.75% – 2.30% | 1,700 – 10,600 | 1.7 – 63.6 |
0.28 – 2.90 |
| Median |
1.25% |
5,220 |
15.1 |
1.20 |
| Mean |
1.53% |
5,450 |
20.7 |
1.32 |
