Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, acetates

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: data from the EU Risk Assessment DODMAC (2002)

Justification for type of information:

The primary component of all substances provide complete coverage of 68334-33-8. 68334-33-8 shares high structural similarity with 61789-80-8, 68783-78-8, 107-64-2, and 112-02-7. As 68334-33-8 is a UVCB its components encapsulate the other substances except for the counter ion (Cl-). In solution, the counter ions will dissociate from the parent structures. Therefore, we are comparing substances of equivalent nature. CAS 107-64-2 represents the C18 boundary of the 61789-80-8. Ignoring the salt component CAS 61789-80-8 is equivalent to CAS 68334-33-8. 68783-78-8 is a worst case of both 68334-33-8 and 61789-80-8 since it is unsaturated and the SP2 carbon-carbon bonds are of higher reactivity and a more likely site of metabolic activation. The primary component of CAS 112-02-7 is a substructure of all the other substances. Additional documentation, provided within the IUCLID Assessment Reports section, supports the read-across approach.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

Algae were tested in river water and laboratory water.

GLP compliance:

not specified

Analytical monitoring:

not specified

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

not specified

Water media type:

freshwater

Total exposure duration:

5 d

Hardness:

20 mg/L CaCO3 (Laboratory water)
299 mg/L CaCO3 (White River)

pH:

7.3 (White River)

Details on test conditions:

68 mg/L suspended solids
0.2 μg/L MBAS

Duration:

5 d

Dose descriptor:

NOEC

Effect conc.:

0.062 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

cell number

Remarks on result:

other: Water from White river: pH 7.3, 299 mg/L CaCO3, 68 mg/L suspended solids

Duration:

5 d

Dose descriptor:

NOEC

Effect conc.:

0.078 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

cell number

Remarks on result:

other: Laboratory water: 20 mg/L CaCO3

Conclusions:

5-day NOEC: 0.062 mg/L (cell number; river water)
5-day NOEC: 0.078 mg/L (cell number; laboratory water)

Executive summary:

The influence of different test media on the sensitivity of Selenastrum capricornutum towards DHTDMAC (71.4% active ingredient) was investigated. Laboratory water with a hardness of 20 mg/L CaCO3 (no further characterization) and algae nutrient enriched White River water (Indiana) of the following quality prior to autoclaving were used: pH = 7.3, total hardness = 299 mg/L CaCO3, 68 mg/L suspended solids, 0.2 μg/L MBAS) In laboratory water a NOEC of 0.078 mg/L and an algistatic concentration of 0.228 mg/L were derived for the reduction of cell number after 5 days (nominal concentrations of active ingredient). The corresponding values for the river water were: NOEC = 0.062 mg/L and algistatic concentration = 0.708 mg/L. The table shows that results for Microcystis aeruginosa are similar (cited in EU Risk Assessment).

 

Selenastrum capricornutum	5d NOEC	0.078 mg/L	DHTDMAC	Laboratory water	EG & G Bionomics, 1981
	5 d EC100	0.228 mg/L	DHTDMAC	Laboratory water
	5d NOEC	0.062 mg/L	DHTDMAC	River water
	5 d EC100	0.708 mg/L	DHTDMAC	River water
Microcystis aeruginosa	5d NOEC	0.13 mg/L	DHTDMAC	Laboratory water	EG & G Bionomics, 1981
	5 d EC100	0.32 mg/L	DHTDMAC	Laboratory water
	5d NOEC	0.078 mg/L	DHTDMAC	River water
	5 d EC100	0.21 mg/L	DHTDMAC	River water

 

Key value for chemical safety assessment

EC50 for freshwater algae:

0.48 mg/L

EC10 or NOEC for freshwater algae:

0.062 mg/L