If solubility is below 10%, what is recommended?

• A. Use a surfactant
• B. Do nothing
• C. Increase temperature
• D. Add acid

Answer: (A)

When a contaminant has very low solubility in water, cleanup by water alone is difficult because the contaminant tends to stay attached to soils and sediment rather than dissolving. A surfactant helps by forming micelles and reducing interfacial tension, which allows the contaminant to partition into the micellar phase or become solubilized. This increases the contaminant’s apparent solubility and makes it easier to mobilize or remove during treatment.

Using a surfactant is the most effective way to enhance solubility in this situation, whereas doing nothing won't address the low solubility issue, increasing temperature can help but isn't always practical or sufficient on its own, and adding acid changes chemistry in ways that may not improve solubility for many contaminants and could cause other issues.