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Ecotoxicological information

Toxicity to soil microorganisms

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Description of key information

Concentrations of acrylic acid in a sandy loam soil up to 100 ppm (= mg/kg soil ww) 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 ww (Sandy loam soil, OECD TG 217, draft)

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Additional information

No data on toxicity to soil microorganisms are available for sodium acrylate. Therefore, results from investigations on the structural analogous substance acrylic acid were taken into account for the assessment of toxicity to soil microorganisms of sodium acrylate.

A study was conducted according to the OECD Chemicals Testing Programs 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 ww). 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.