A surfactant is a chemical that increases the permeability of one substance to another. It allows oil and water to mix where they normally would not. Surfactants have numerous applications in cosmetics, insecticides, household products, paint and ink. Surfactants are used to clean soil and to increase soil’s water-absorption abilities.
Gasoline-contaminated soil is effectively cleaned with surfactant-enhanced washing solutions. Past EPA research determined that cleaning chemically contaminated soil is more efficient and economical with surfactants than with water-only cleaners. They are used to clean diesel, mineral and heavy crude oils from areas identified by the EPA as contaminated.
Surfactants are used as soil amendments to help soil retain water. Soil surfactants move water quickly off the surface of the soil and enable water to penetrate the soil and move laterally and vertically into the root zone. As water becomes a scarce commodity, farmers seek ways to enhance soil’s water-absorption capabilities. The long-term effect of surfactant synthetic chemicals on soil health has not been determined.
Guidelines established by the USDA National Organic Program for growers prohibit the use of synthetic chemical soil amendment products such as surfactant treatments. “Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony,” according to the NOP website.
Although surfactants have been used to disperse oil spills on ocean water, controversy remains about the adverse side-effects to marine life. The combination of oil and chemical dispersant severely disrupts the natural marine food web, according to Dr. Susan Shaw of the Marine Environmental Research Institute (MERI). Surfactants used in soil treatment may have a similar effect on soil-food web populations.
Soil Food Web
“Soil health is defined by its ability to perform essential ecosystem functions such as: nutrient cycling, water filtration and habitat provision for plants and animals,” according to Dr. Elaine Ingham. When the soil-food web is disturbed by the addition of chemicals such as those in surfactants, the ecosystem becomes unhealthy. The nutrient-enhancing capacities of living organisms in the soil are suppressed by toxic chemicals. Unhealthy soil produces less nutritious fruits and vegetables.