Denatonium benzoate

Endpoint summary

Additional information

Short-term toxicity to fish:

Fish Acute Toxicity test according to OECD Guideline 203 was conducted for Denatonium benzoate (granular form). The nominal concentration selected for the experiment were 6.25 mg/L, 12.5 mg/L, 25 mg/L, 50 mg/L & 100 mg/L and Zebra fishes were exposed to these concentration for 96 hours. The lethal concentrations LC50 was found to be > 100mg/L indicatingthat denatonium benzoate isnot likely to exhibit toxicity to fish as per the CLP criteria.

Short-term toxicity to aquatic invertebrates:

No. of studies of target substance denatonium benzoate (CAS No 3734-33-6)reviewed for Short-term toxicity to aquatic invertebrates from reliable sources having Klimisch rating 4.

The summary of the results are presented below:

Sr.No	Endpoint	Effect values	Basis for effects	Duration	Species	Sources
1	LC50	>500 mg/L	Mortality	24 hrs.	Daphnia magna	Study report
	LC50	>500 mg/L	Mortality	48 hrs.
	NOEC	50 mg/L	Appearance of a white line on their back	48 hrs.
2	LC50	400 mg/L	Mortality	96 hrs.	Crangon sp.	Study report

 

By applying weight of evidence approach to the target substancedenatonium benzoate, the endpoint value was found to vary between LC50= 400 to >500 mg/l in a 24, 48 & 96 Hours respectively. Study on the basis of mortality effect. Thus considering the CLP Criteria for aquatic classification of the substance, it is concluded that substance does not exhibit short term toxicity to aquatic invertebrate (Daphnia magna).

Toxicity to aquatic algae and cyanobacteria:

The effect of test substance Denatonium Benzoate (granular form), CAS No. 3734-33-6 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga growth inhibition test. The test concentration chosen for the study were 6.25 mg/l, 12.5 mg/l, 25mg/l, 50 mg/l, 100mg/l and 200 mg/l. The test concentrations were prepared using stock solution of the test substance using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of test substance. EC50 calculated graphically through probit analysis was observed to be 281.556mg/l indicating that denatonium benzoate is not likely to exhibit toxicity to aquatic algae as per the CLP criteria.

Toxicity to microorganisms

The toxicity of Denatonium benzoate to micro-organisms was estimated using QSAR Toolbox version 3.3

The EC50 value of Denatonium benzoate in Vibrio fischeri during a 15 minute exposure was estimated to be 511.58 mg/L based on the effects on behaviour of the organisms. This value indicates that the substance is not likely to exhibit toxicity to micro-organisms.