Registration Dossier

Administrative data

Description of key information

Rat oral LD50 > 10000 mg/kg bw
Rat inhalation LC50 > 1895 mg/m3
Rat dermal LD50 > 2000 mg/kg bw

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
10 000 mg/kg bw
Quality of whole database:
The study is supported by many other studies on the substance and in agreement with the results for all category members (see Category Justification Report in section 13). Substance purity > 80 %.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
1 895 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
2 000 mg/kg bw

Additional information

Several acute toxicity studies were performed on the substance under registration. The most reliable was performed with a purity of the test substance > 80 % and resulted in LD50 very high, over 10000 mg/Kg bw. Some studies resulted in a lower LD50 (between 5000 and 10000), but purity was reported as less than 50 % and no information on the other constituents is provided.

In conclusion, an LD50 greater than 10000 mg/Kg bw has been set for the substance under registration.

A valid GLP study for acute dermal toxicity was reported (RCC, Research & Consulting Company AG., 1991), performed just at 2000 mg/Kg bw with no effect. The tested substance is the analogous CAS 16470-24-9, the dihydoxyethyl derivative tetrasulphonated, belonging to the Stilbene Fluorescent Whitening Agents category, group 3. It has similar organic functional groups, while the sulphonation degree is higher than that of CAS 13863-31-5, therefore CAS 16470-24-9 has also higher salification degree.

Skin adsorption was evaluated and calculated for all members of the category (see Category Justification Report, Section 13 of the dossier).

As it can be noted, the influence of the variability in functional group is very low, more related to the variability in the polarity of the substance than on potential reactivity that can arise a concern. From a metabolic point of view, estimation with OECD Toolbox of the dermal metabolism was performed in order to verify if breakdown products may be formed. Results are negative for all members. Oral acute toxicity is also comparable for the two substances (CAS 16470-24-9 and 13863-31-5), with very high estimated LD50. The two substances are expected to have a similar behaviour regarding dermal acute toxicity, as well as all the other members of the Stilbene Fluorescent Whitening Agents category.

Because of the physical state and the trade forms, inhalation is not an appropriate route of exposure. Acute toxicity results for the other two exposure routes indicate no concern therefore no testing was performed. One test is available on an analogous substance, performed at the maximum allowed concentration of 1890 mg/m3: no effects were observed. The analogous substance, part of the Stilbene Fluorescent Whitening Agents, group 3, is the acid form of the disulphonated derivative dihydroxyethyl derivative, therefore contains the same organic functional groups, but due to the sulphonation/salification degree is less soluble. This property makes the Read Across substance CAS 4404-43-7 a conservative representative because of the potential higher bioavailability.

As a conclusion, it can be stated that the substance is not acutely toxic for all the three exposure ways.


Justification for selection of acute toxicity – oral endpoint
Study conducted according to internationally accepted testing guidelines.

Justification for selection of acute toxicity – dermal endpoint
Study conducted according to internationally accepted testing guidelines, in GLP on an analogous substance of the category.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.1 Acute toxicity section, substances can be allocated to one of four toxicity categories based on acute toxicity by the oral, dermal or inhalation route according to the numeric criteria. Acute toxicity values are expressed as (approximate) LD50 (oral, dermal) or LC50 (inhalation) values or as acute toxicity estimates (ATE).

The oral LD50 value was established to be greater than 10000 mg/kg body weight, therefore the test substance is out of any classification limit for acute oral toxicity (oral acute toxicity category 4: 300 < ATE ≤ 2000 mg/kg bw).

The dermal LD50 value was established to exceed 2000 mg/kg body weight, which exceeded the highest CLP classification limit (dermal acute toxicity category 4: 1000 < ATE ≤ 2000 mg/kg bw).

The inhalation LC50 value was established to be greater than 1895 mg/m3. For powder the limit for classification is ATE > 5 mg/l i. e. 5000 mg/m3.

Since no effect was observed at the tested concentration and this was the maximum reachable concentration in the test condition, it is assumed that the substance is not classified for inhalation acute toxicity.

In conclusion, the available experimental data are adequate for classification and labelling and the test substance is non classified for oral and dermal acute toxicity, according to the CLP Regulation (EC 1272/2008).