Quaternary ammonium compounds, di-C14-18-alkyldimethyl, Me sulfates

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: quaternary ammonium and saturated or unsaturated alkyl chains with comparable length (corresponding to scenario 2 of the read-across assessment framework)

The read-across hypothesis is based on structural similarity of target and source substances. Based on available experimental data, including key physicochemical properties and data from acute toxicity, irritation, sensitization (human) and genotoxicity studies, the read-across strategy is supported by a quite similar toxicological profile of all substances.

Therefore, read-across from the existing ecotoxicity, environmental fate and toxicity studies conducted with the source substances is considered as an appropriate adaptation to the standard information requirements of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

A justification for read-across is attached to IUCLID section 13.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See justification for read-across attached to IUCLID section 13.

3. ANALOGUE APPROACH JUSTIFICATION
See justification for read-across attached to IUCLID section 13.

4. DATA MATRIX
See justification for read-across attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across source

Test organisms (species):

other: Pseudomonas putida, or inoculum from a predominantly domestic wastewater treatment plant, or nitrifying bacteria

Water media type:

freshwater

Duration:

18 h

Dose descriptor:

EC50

Remarks:

Pseudomonas putida, Bringmann & Kühn method

Effect conc.:

>= 48 - <= 58 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

EC50

Remarks:

Activated sludge

Effect conc.:

520 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Key result

Duration:

119 h

Dose descriptor:

IC50

Remarks:

Nitrifying bacteria

Effect conc.:

2.1 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of nitrification rate

Duration:

3 h

Dose descriptor:

EC50

Remarks:

Anaerobic bacteria from a domestic wastewater treatment plant

Effect conc.:

220 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Conclusions:

Nitrifying bacteria were found to be the most sensitive microorganisms with the lowest EC50 of 2.1 mg/L on which the risk assessment should be based.

Description of key information

EC50 of 2.1 mg/L (nitrifying bacteria; read across from DHTDMAC)

Key value for chemical safety assessment

EC50 for microorganisms:

2.1 mg/L

Additional information

No experimental data are available for the target substance Di-C14-18 alkyldimethyl ammonium methosulfate. However, toxicity studies in algae are available for the closely related source substance DHTDMAC. A justification for read-across is attached to IUCLID section 13.

Several studies are cited in the EU Risk Assessment Report on DODMAC (2002):

"The toxicity of DHTDMAC to Pseudomonas putida was investigated in a growth inhibition test according to a German DIN-guideline (Bringmann & Kühn method; UBA, 1992). In two tests EC50-values of 48 and 58 mg/l were derived after 18 hours (nominal values, graphically extrapolated).

In an activated sludge respiration inhibition test (OECD 209) inoculum from a predominantly domestic wastewater treatment plant was used (UBA, 1992). A 3h EC50 of 520 mg/l was derived graphically from the dose response curve. The corresponding statistically derived value was 267 mg/l (nominal concentrations).

The toxicity of DHTDMAC to nitrifying bacteria enriched in a laboratory wastewater treatment plant (domestic sludge originally) was investigated in a manometric respirometer test (Wagner & Kayser, 1990). The test duration in the reference was referred to between 119 and 254 hours for different substances and was stopped when the nitrification of the controls was completed. The IC50 for inhibition of respiration was 2.1 mg/l active ingredient of DHTDMAC (a carrier solvent was used).

Anaerobic bacteria from a domestic wastewater treatment plant were exposed to DHTDMAC in an OECD 209 test (Hoechst, 1989). The inhibition of respiration was measured after 3 hours and the EC10 was 80 mg/l, the EC50 = 220 mg/l."

Overall, nitrifying bacteria were found to be the most sensitive microorganisms with an EC50 of 2.1 mg/L on which the risk assessment should be based.