Benzododecinium chloride

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is readily biodegradable

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Based on the available weight of evidence information from OECD 30B and OECD 301D studies with the test and/or the read across substances showing degradation percentages ranging from 23 to 100% for the test substance and 88.9% for the read across substance at a range of concentrations, suggests that the test substance, C12 ADBAC can be overall considered to be readily biodegradable.

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Study 1:A study was conducted to determine the ready biodegradability of the test substance, C12 ADBAC (purity not specified), using closed bottle test, according to the OECD Guideline 301D. The inoculum used was one drop/L of filtered effluent from sewage works treating predominantly domestic sewage. The test was conducted in two different laboratories using 2, 3.2 and 5 mg/L test concentrations at 20 +/- 1 deg C, followed by BOD determinations after 5, 15 and 28 days. The three test concentrations resulted in 43, 23 and 36% degradation after 28 days. The lowest (2 mg/L) and highest concentrations (5 mg/L) revealed long delay with partial degradation, while the mid concentration (3.2), showed little or no biodegradation. The lag phase was attributed to the toxicity of the test substance to the inoculum. Based on the growth inhibition test conducted for test substance, the EC50 value was determined to be 3.2 -7.5 mg/L. Therefore, the test concentration below the EC50 value i.e., 2 mg/L results in the highest degradation potential. No further details about biodegradation were available. Under the study conditions, the test substance was considered to be not readily biodegradable and this is attributed to the toxicity of the test substance to the inoculum instead of inertness (ECETOC, 1986).    

Study 2:A study was conducted to determine the ready biodegradability of the test substance, C12 ADBAC (purity not specified), using Sturm test, according to the OECD Guideline 301B. The inoculum used was collected from a local sewage works which treated predominantly domestic effluents. The inoculum at a concentration of 15 mg/L suspended solids (SS) was pre-aerated for eight days at 23 deg C in the mineral solution before addition of the test substance. The test was conducted at two test concentrations: 6.8 and 13.5 mg/L at 23 deg C, followed by CO2 determinations after 3, 5, 7, 14 and 21 days. The two test concentrations resulted in 100 and 92% degradation after 21 days. Based on the growth inhibition test conducted for test substance, the EC50 value was determined to be 10 - 24 mg/L. Therefore, the test concentration below the EC50 value i.e., 6.8 mg/L results in the highest degradation potential. No further details about biodegradation were available. Under the study conditions, the test substance was considered to be readily biodegradable (ECETOC, 1986).   

Study 3: A study was conducted to determine the biodegradation of the read across substance, C12-16 ADBAC (purity not specified), in water according to OECD Guideline 301B (CO2 evolution test). Flasks containing inoculum from a household water-treating plant dosed with the equivalent of 5 mg C/L test or 20 mg C/L reference substances were maintained for 28 d. Testing at low concentrations, was required due to the toxicity of the read across substance towards the inoculum at higher concentrations. Biodegradability was calculated from the released CO2 over time in the test and reference flasks compared to the blank control (a flask prepared without test or reference substance). CO2 production in the blank (inoculum control) was 39.2 mg. Biodegradability in the reference flask was determined to be 88.9% after 28 d. Under the test conditions, the biodegradation of the read across substance in water was determined to be 95.5% after 28 d (CO2 evolution). The read across substance was considered to be readily biodegradable (van Dievoet, 2005). Based on the results of read across substance study, similar degradation potential can be expected for the test substance.     

The available information on the test and read across substances indicates that the slow or lag in the degradation potential of the substances at higher concentrations is not due to inertness of the substance but due to toxicity to the inoculum. It is generally recommended that the concentration of the substance in the biodegradation test should not exceed 1/10th of the EC50 determined in the toxicity tests. However, this was not the case in the available biodegradation tests with the test substance, as the EC50 value for toxicity to micro-organisms ranges from 3.2-40 mg/L (ECETOC, 1986). In light of these facts and based on the available weight of evidence information from studies with the test and/or the read across substances, suggests that the test substance, C12 ADBAC can be overall considered to be readily biodegradable. ​