Quaternary ammonium compounds, bis(C16-18 and C18-unsatd. alkyl)dimethyl, chlorides

Endpoint summary

Description of key information

There are no experimental data for DTDMAC available. Read across was performed to the structural closely related quaternary ammonium compound dihydrogenated tallowalkylammonium chloride (DHTDMAC, No. 61789 -80 -8) for which an EU risk assessment exists. To use read-across is justified not only by structural similarities but also due to comparable physical-chemical properties like water solubility, log Pow, degree of unsaturation / saturation, chain length and molecular weight. There is one valid acute oral toxicity study in rats for assessment purposes available. The resulting LD50 value is >2000 mg/kg body weight for DHTDMAC having a comparable chain-length distribution but higher degree of saturation. A low acute systemic oral toxicity potential of DTDMAC can be anticipated.
No acute dermal and/or inhalation toxicity study was performed on the substance due to its corrosive effects to the skin. However, testing of dihydrogenated tallowalkyldimethyl ammonium chloride (DHTDMAC, CAS No. 107-64-2) for acute dermal systemic toxicity has not revealed any target organs and/or signs of systemic toxicity. The medium lethal dose (LD50) was greater than 2000 mg/kg body weight. Additionally, results from an inhalation study with DHDTMAC revealed an LC50 greater 180 mg/L for a 1 hour exposure.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

There are no studies available for ditallowalkyldimethylammmonium chloride (DTDMAC) with regard to acute systemic toxicity. However, based on the corrosive properties of the substance, waiving of additional acute oral toxicity test on the pure undiluted substance is scientifically justified and the use of read-across for the assessment of the acute toxicity of DTDMAC is appropriate. Clustering quaternary ammonium compounds for assessment purposes was also considered appropriate by the U.S. EPA for registration purposes under FIFRA because of similar toxicological profiles of dialkyldimethylammonium chlorides. Considering the overall toxicity profile of dialkyladimethylammonium compounds it becomes apparent that the toxicological profile of quaternary ammonium compounds is mainly depending on the chain-length distribution and the degree of saturation of the alkyl groups which determine chemical reactivity and that irritative properties are predominating. With regard to DTDMAC read-across to quaternary ammonium compounds having a shorter chain-length distribution with a similar degree of unsaturation on one side and quaternary ammonium compounds having a comparable chain-length distribution but a higher degree of saturation on the other side, should allow scientifically reasonable comparisons and reliable estimates of the toxicity profile of DTDMAC.

A low acute oral toxicity of DTDMAC is supported by results from an acute study with DHTDMAC (CAS No. 92129-33-4) with LD50 greater 2000 mg/kg body weight. No acute dermal toxicity study was performed on the substance due to its corrosive effects to the skin. However, testing of DHTDMAC for acute dermal systemic toxicity according to OECD guideline 402 has not revealed any target organs and/or signs of systemic toxicity. The medium lethal dose (LD50) was greater than 2000 mg/kg body weight.

With regard to acute dermal systemic toxicity, read-across from data on dihaydrogenated tallowalkyldimethylammonium chloride (DHTDMAC, purity approximately 97%) indicate no toxicity potential of concern. Clinical signs of toxicity, macroscipocal visible organ changes and/or mortality was not observed. The median lethal dose (LD50) in an OECD guideline 402 test with DHTDMAC was greater 2000 mg/kg body weight in rats.

An inhalation toxicity study in rats conducted on DHTDMAC has also not provided indications of acute systemic toxicity. The acute LC50 of DHTDMAC was greater than 180 mg/L after a 1 hour exposure period.

Taking read-across into account it is concluded from the available data, that DTDMAC does not represent a significant acute systemic toxic hazard. Because of their closely related structures and similar physico-chemical properties, dialkyldimethylammonium chlorides possess similar human health-related effects and additional testing with DTDMAC is not required. Additional testing of DTDMAC for acute systemic toxicity is also not justified scientifically because of animal welfare reasons. The substance is classified as corrosive to skin and testing for acute toxicity is therefore not needed according to REACH regulation (EC) 1907/2006 (Annex VII, point 8.5, column 2) and risk reduction measures have to apply. Additionally, based on the low vapour pressure of the substance a significant risk concerning inhalation is not anticipated.

Justification for classification or non-classification

Based on all available data on dialkyldimethylammonium chlorides in general, the acute oral toxicity of DTDMAC is considered to be greater than 2000 mg/kg body weight in rats. In accordance with the criteria laid down in Regulation 1272/2008/EC (CLP) the substance is not classified for this endpoint.

No classification is indicated for the other routes of exposure. Taking into account the skin corrosive properties of DTDMAC special attention has to be given to risk management and no additional testing is justified.