Toxicity assessment of using polyurethane spray foam as a soil additive

The potential for acute toxicity associated with using polyurethane spray foam insulation as a soil additive was investigated in microbial, plant, and animal life. An acute toxicity test on an activated sludge was conducted using a respirometer. Varying levels of water soluble portions of polyurethane foam were added to cultures of activated sludge and the respiration rate was measured. The toxicity of an activated sludge culture was determined by a decrease in respiration rate as compared to a control. Acute toxicity on plant life was conducted on soybean plants. The test was conducted by introducing varying levels of heat treated and non-heat treated polyurethane foam to soil at varying concentrations and comparing the biomass of the plants grown in the soil amended with the spray foam to a control. Toxicity was determined based upon a decrease in biomass as compared to the control. Acute toxicity on animal life was conducted on earthworms by introducing varying levels of heat treated and non-heat treated polyurethane foam to an artificial soil environment to which the earthworms were introduced for one week. The toxicity to the earthworms was determined based upon the number of surviving worms at the end of the week as compared to the control. Based upon the results of the study further research should be conducted before the polyurethane spray foam insulation is used as a soil additive.