Bis(4-chlorophenyl) sulphone

Endpoint summary

Description of key information

DCDPS is not acute toxic.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

4 810 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

10 000 mg/kg bw

Additional information

Oral route

The oral toxicity LD50 of DCDPS was found to be 4810 mg/kg bw in female and 5400 mg/kg bw in male rats, and 5189 mg/kg bw for both sexes combined (BASF, 1981). The study is comparable to OECD TGD 401. The study is considered conclusive and yields the lowest reported value. Finally, a limit study conducted as a pre-test confirms the absence of mortality and acute toxic effects at a dose of 2000 mg/kg bw (Huntingdon, 2000).

 

Dermal route

Taking into account the very low acute oral toxicity of DCDPS (LD50 rat, combined sexes: 5189 mg/kg bw) and the fact that absorption from the gastrointestinal tract is complete, whereas only a moderate dermal absorption is assumed (see IUCLID section 7.1 “toxicokinetics, metabolism, distribution”), the acute dermal toxicity of DCDPS is expected to be even lower than its acute oral toxicity.

This route-to-route extrapolation is in agreement with the dermal LD50 of >10000 mg/kg bw for the rat after a 24 h exposure, which has been reported by ICI (1991) and the low toxicity following intraperitonal application in mice (LD50 = 2448mg/kg bw, Microbiological Associates 1991).

In summary, there is sufficient weight of evidence from the above information leading to the conclusion that the acute dermal LD50 of DCDPS is above the regulatory threshold of 2000 mg/kg bw.

 

Inhalation route

There are no relevant experimental data available. However, due to the negligible vapor pressure of 1.5 x 10E-5 Pa (at 25°C) and the particle size distribution (PM100: <8%, PM10: 0%) a considerable exposure of the respiratory tract can be excluded and animal testing for acute inhalation toxicity is not appropriate. This is in accordance with REACH regulation 1907/2006/EC Annex VIII and ECHA (2008) "Guidance on information requirements and chemical safety assessment" Chapter R.7a.

In detail a particle size distribution study of standard DCDPS crystalline powder revealed that only 7.8% of the particles were <=100μm (inhalable fraction) and no particles <=10μm (thoracic fraction) existed. Furthermore the water solubility of the substance is very low (0.86 mg/l, Boelhouvers 2004), which is of course only estimating the solubility in the liquid lining of the upper respiratory tract. Due to the low (estimated) solubility and the exposure of only the upper respiratory tract it can be anticipated that the particles can be removed readily from the respiratory tract ahead of dissolving and being bioavailable in in considerable amounts. Furthermore at the maximally achievable vapor concentration DCDPS did not exhibit any signs of local or systemic toxicity (BASF AG, 1981).

 

Intraperitoneal application

Microbiological Associates (1991) determined the LD50 following single dose intraperitoneal injection. An LD50 of 2448 mg/kg bw was idenified in a toxicity pre-test to a erythrocyte micronucleus test in male and female mice.

Justification for classification or non-classification

Integrating the information available for acute toxicity, DCDPS is not subject to classification for acute toxic effects according to Directive 67/548/EEC and Regulation 1272/2008/EC.