Acrylic acid

Toxicity to soil microorganisms

Description of key information

Concentrations of acrylic acid in a sandy loam soil up to 100 ppm (= mg/kg soil dw) had no effect on the respiration of the micro-flora, but a concentration of 1000 ppm acrylic acid completely suppressed respiration.

EC0 = 100 mg/kg soil dw (Sandy loam soil, OECD TG 217, draft)

EC100 = 1000 mg/kg soil dw (Sandy loam soil, OECD TG 217, draft)

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

100 mg/kg soil dw

Additional information

A study was conducted according to the OECD Chemicals Testing Programme UPEC/3 “Guidelines for assessing the toxicity of chemicals to soil micro-organisms; Carbon cycle", 4th draft, 1981 in order to determine the effects of a range of concentrations of acrylic acid on the respiration of the soil micro-flora and establish the concentration which was toxic to the micro-flora. One soil type, a sandy loam soil, was used. The test material dissolved in water was mixed in bulk with the soil to give a range of concentrations: 0.1, 1, 10, 100, and 1000 ppm (= mg/kg soil dw). Portions of the treated soil, together with non-treated controls, and a sterile control were placed in triplicate respirometer flasks connected to an air-pump via a suitable gas-scrubbing system to remove CO₂ for a test period of 28 days. Air exiting from the respirometers was collected in CO₂-traps of sodium hydroxide solution. The carbon dioxide evolved by control and treated soils was determined. The results obtained showed that the respiration rates in soil containing 0.1 – 100 ppm acrylic acid were very similar to the control soil. The soil containing 1000 ppm acrylic acid showed a very depressed respiration being similar to the sterile soil containing the same amount of substance. Thus, it was concluded that concentrations of acrylic acid up to 100 ppm were non-toxic to the soil micro-flora, while a concentration of 1000 ppm was highly toxic.