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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Read-across, key study,test substance: barium chloride dehydrate, activated sludge of a predominantly domestic sewage, 3 h; EC50 ≥ 1000 mg/L nominal BaCl2; NOEC ≥1000 mg/L nominal BaCl2 (GLP, OECD 209 guideline study, Egeler and Kiefer, 2010). Based on the results with the analogous test substance the EC50 and NOEC of barium titanium are therefore higher than 1119 mg/L (calculated from its molecular weight).

Key value for chemical safety assessment

EC50 for microorganisms:
1 119 mg/L
EC10 or NOEC for microorganisms:
1 119 mg/L

Additional information

In order to assess the toxicity to microorganisms of the analogous test substance barium chloride dihydrate (purity: > 100.6 weight-%), the test in activated sludge of a predominantly domestic sewage was performed according to the method described in OECD guideline 209 (Egeler and Kiefer, 2010). Nominal dose levels of the test item used were: 0, 3.8, 11.7, 37.5, 117, 375 and 1173 mg/L; this corresponds to 0, 3.2, 10, 32, 100, 320 and 1000 mg/L of BaCl2. The activated sludge was exposed to the test substance for 3 hours in fresh water under static conditions.

Since the nominal test item concentrations of 10, 32, 100, 320, and 1000 mg BaCl2/L showed no statistically significant inhibitory effect on the respiration rate of the test system, no ECx-values were determined. The concentrations initially measured in the test solutions were in good agreement with the target concentrations; therefore it can be assumed that the activated sludge was exposed to at least 94% of the nominal concentrations throughout the test. Thus, the results of this study demonstrate that the test item did not inhibit respiration of activated sludge at a concentration up to 1000 mg/L. Toxic effect levels (EC20, EC50 and EC80) are therefore greater than 1000 mg BaCl2/L. The No Observed Effect Concentration (NOEC) is 1000 mg BaCl2/L, and hence the Lowest Observed Effect Concentration (LOEC) is > 1000 mg BaCl2/L under the test conditions chosen.

Based on the results with the analogous test substancetheEC50 and NOEC of BCZT are therefore higher than 1119 mg/L(calculated from its molecular weight).