Arsenic acid

Endpoint summary

Description of key information

- Oral: LD50 (male/female) for arsenic acid (75% w/w) = 149.6 (114.4-195.5) mg/kg bw for mice (OECD TG 401)
- Dermal: LD50 (male/female) for arsenic acid = 2000 (1583-2417) mg/kg bw for rabbits (OECD TG 402)
- lnhalation: LC50 (male/female) for arsenic acid (aerosol) = 1.040 (0.512-1.567) mg/L for mice (OECD TG 403)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

149.6 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

1 040 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

In an acute oral toxicity study performed similarly to OECD guideline 401 and in compliance with GLP, groups of Crl:CD-1 (ICR) BR mice (5/sex/dose) were given a single oral dose of arsenic acid (75% w/w) at 75, 100 and 200 mg/kg bw. The acute oral LD50 for males and females were determined to be 141.4 (98.8-202.3) and 160.4 (107.1-240.3) mg/kg bw, respectively. The combined oral LD50 was calculated to be 149.6 (114.4-195.5) mg/kg bw.

 

In an acute dermal toxicity study performed similarly to OECD guideline 402 and in compliance with GLP, groups of New Zealand White rabbits (5/sex/dose) received a single dermal dose of Desiccant L-10 (arsenic acid) at 200, 400, 800, 1600 and 3200 mg/kg bw on clipped area of the trunk representing at least 10% of the total body surface area. Dermal reactions noted in several animals were necrosis followed by eschar formation and exfoliation. The acute dermal LD50 for males and females were determined to be 1750 (944-2556) and 2300 mg/kg bw, respectively. The combined dermal LD50 was calculated to be 2000 (1583-2417) mg/kg bw.

 

In an acute inhalation toxicity study performed similarly to OECD guideline 403 and in compliance with GLP, groups (5/sex) of CD-1 mice were exposed (whole-body) to aerosol atmosphere of arsenic acid at concentrations of 0.57, 1.01 and 2.41 mg/L (analytical TWA) or 24.9, 49.1 and 206.7 mg/L (nominal) for 4 hours. The acute inhalation LC50 for males and females were determined to be 0.794 (0.548-1.149) and 1.153 (0.410-1.897) mg/L (analytical), respectively. The acute inhalation combined LC50 was 1.040 (0.512-1.567) mg/L (analytical).

Justification for classification or non-classification

- The oral LD50 for arsenic acid (75% w/w) is in the range of 50-200 mg/kg bw in mice therefore it is classified as ‘R25 Toxic if swallowed’ according to the Annex VI to the Directive 67/548/EEC and ‘category 3’ according to the CLP Regulation (EC) N° (1272-2008).

- The dermal LD50 for arsenic acid was calculated to be 2000 (1583-2417) mg/kg bw in rabbits therefore it is classified as ‘R21 Harmful in contact with skin’ according to the Annex VI to the Directive 67/548/EEC and ‘Category 4’ according to the CLP Regulation (EC) N° (1272-2008).

- The inhalation LC50 for arsenic acid (aerosol) is 1 mg/L in mice therefore it is classified as ‘R23 Toxic by inhalation’ according to the Annex VI to the Directive 67/548/EEC and ‘Category 3’ in the CLP Regulation (EC) N° (1272-2008).