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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Effect value for assessment (activated sludge, respiration):
14d-LOEC = 500 mg PBS/L; 124 mg H2O2/L; 40 mg B/L

Key value for chemical safety assessment

Additional information

Gerike et al. (1976) tested the influence of sodium perborate trihydrate on the activity of activated sludge, indicated by the decrease of methylenblue (MBAS) and the chemical oxygen demand (COD) in laboratory models of waste water treatment plants (OECD confirmatory test). The test substance was applied in wastewater, adapted for 2 weeks, at concentrations of 125, 250 and 500 mg PBS/L (31, 62 and 124 mg H2O2/L; 10, 20 and 40 mg B/L). The retention time in the activated sludge vessels was 3 hours. For both parameters concentrations of up to 250 mg PBS/L (62 mg H2O2/L; 20 mg B/L) showed a slight increase, indicating a slight improvement in the clean-up performance of activated sludge. At 500 mg PBS/L (124 mg H2O2/L; 40 mg B/L) a slight inhibitory effect was observed but not quantified.

Dimkov et al. (1985) examined the effect of sodium perborate on the biodegradation of alkylbenzene sulphonates by Pseudomonas fluorescens and Aspergillus sp., isolated from nonadapted sewage effluent. No exact information was given on test conditions and the nature of the perborate compound used. The presence of 20% sodium perborate in detergents reduced the biodegradation of alkylbenzene sulphonates for Pseudomonas fluorescens by 65% and for Aspergillus sp. by 40%. Sodium perborate reduced biomass growth of both strains to a lesser degree than biodegradation.

Further information from tests with degradation products

From a cell multiplication inhibition test on the toxicity of hydrogen peroxide on Pseudomonas putida an EC10 value of 11 mg/L (nominal concentration) was reported, which is in contrast to the low value determined for sodium perborate with the same bacterium. In an activated sludge respiration inhibition test (according OECD guideline 209) with non-adapted sludge an EC50 value of 466 mg/l was determined. Bacteriostatic effects of hydrogen peroxide on Pseudomonas aeruginosa and Staphylococcus aureus were observed at a concentration of 5.1 mg/L (EU Risk Assessment Report on Hydrogen Peroxide).

The most sensitive effect value on the toxicity of boric acid on microorganisms reviewed by ECB (2009, Assessment Report Boric acid. Product-type 8 (Wood preservative). 20 February 2009) was a respiration test on activated sludge with a 3h-NOEC of 17.5 mg B/L.