Antimony pentachloride

Endpoint summary

Description of key information

Antimony pentachloride hydrates in the presence of water/moisture, and then decomposes to either antimony trichloride and chlorine, antimony pentoxide and chlorine, or H₃SbO₄ and hydrochloric acid. Conditions under which these various reactions occur are not clear, but require each different pressure and moisture. Assuming that antimony pentachloride can yield Sb^{3 +} ions under some sort of extreme conditions, and that Sb^{3 +} ions are reported to be more toxic than Sb^{5 +} ions, it is proposed to read-across long-term effects of antimony pentachloride from long-term effects data available from trivalent antimony substances, in particular antimony trioxide. This is a worst-case approach which enables a conservative assessment of antimony pentachloride, which is extremely difficult to test due to its corrosivity, and chemical instability. Information from a representative Sb^{5 +} substance (sodium hexahydroxoantimonate) is provided as supporting evidence, to demonstrate the conservatism of the proposed approach for this endpoint. Values to be used in the hazard / risk assessment will be taken from trivalent antimony non-human oral studies.

 

Inhalation:

 

Inhalation studies available on other antimony substances have not been considered for the assessment of antimony pentachloride.

 

Oral:

 

Two repeated dose oral studies (Sunagawa, 1981; Hextet al.,1999) suggest that diantimony trioxide may be toxic to the liver. This being based on a 10 % increase in liver weight. In addition, one study (Hext et al.,1999) exhibited significantly elevated ASAT values and significantly decreased ALP values. The other study(Sunagawa, 1981) revealed both ASAT and ALP levels to besignificantly elevated. However, in the absence of histological change or any clinical signs of antimony intoxication to support liver adversity, the differences are regarded as adaptive or incidental to treatment with diantimony trioxide. A NOAEL of 1686 mg/kg/d for liver toxicity is suggested.

 

Dermal:

 

Dermal studies available on other antimony substances have not been considered for the assessment of antimony pentachloride.

 

 

The following information is taken into account for any hazard / risk assessment:

 

Repeated dose toxicity via oral application: NOAEL=1686 mg/kg bw/day

 

Value used for CSA (via oral route - systemic effects):

No adverse effect observed (NOAEL:1686 mg/kg bw/day) (subchronic; rat)

Recalulated to SbCL5, rthe value of 1686 mg/kg bw/day becomes 1729 mg/kg bw/day

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 686 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

One key study available (90-day repeated dose toxicity study in rats according to OECD 407, under GLP) which is reliable with minor restrictions (RL=2). The overall quality of the database is therefore high.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

0.51 mg/m³

Justification for classification or non-classification

Repeated dose toxicity, oral:

 

The reference Hext P. M., Pinot P. J. and Rimmel B. A. (1999) is considered as the key study for repeated dose toxicity via oral application and will be used for classification. Rats were dosed at 20,000 ppm/day orally via feed for 90 days. Based on the lack of any adverse effects, the no observed adverse effect level (NOAEL) via oral application for diantimony trioxide was established at 1686 mg/kg bw/day.

 

The classification criteria according to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – repeated exposure, oral are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure, and the no observed adverse effect level (NOAEL) via oral application is above the guidance value for a Category 1 classification of 10 mg/kg bw/day and above the guidance value for a Category 2 classification of 100 mg/kg bw/day.

 

For the reasons presented above, no classification for specific target organ toxicant (STOT) – repeated exposure, oral is required.

 

Repeated dose toxicity, dermal:

 

Dermal studies available on other antimony substances have not been considered for the assessment of antimony pentachloride.

No classification for specific target organ toxicant (STOT) – repeated exposure, dermal is required.

 

Repeated dose toxicity, inhalation:

 

Inhalation studies available on other antimony substances have not been considered for the assessment of antimony pentachloride.

No classification for specific target organ toxicity (STOT) – repeated exposure, inhalation is required.