Arsenic acid

Short-term toxicity to aquatic invertebrates

Description of key information

Freshwater species
The 48–hr-acute toxicity of Arsenic acid to Daphnia pulex was studied under static conditions. Daphnids were exposed to control, and test chemical at nominal concentrations in mg/L of: control, 0.25; 0.50; 1.0; 2.0; 5.0 mg/l. Immobilization effects were observed at 0h, 1h, 2h, 4h, 6h and daily thereafter. The 48–hr EC50 was 3.26 mg/L, based on the nominal concentrations.   
This study is classified as acceptable and satisfies with the guidelines requirements for an acute toxicity study with freshwater invertebrates. 
Marine species:
The 48h toxicity of sodium arsenate was tested on the aquatic crustacean Strongylocentrotus purpuratus. The tested concentrations were 0.0023–0.091 mg l-1. Results were expressed in terms of nominal concentrations. On the basis of the data reported, it was possible to derive an EC10 of 6 μg l-1 and an EC50 of 15 μg l-1 based on effects on embryo development. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.26 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

6 µg/L

Additional information

Freshwater species

Several toxicity data are available on daphnia short term toxicity.

Beside the key study, a second data is available on Arsenic V short term toxicity to freshwater invertebrates.

 

The 48–hr-acute toxicity of Arsenic acid to Daphnia magna was studied. Daphnids were exposed to control, and test chemical at nominal concentrations ranged from 29.82 -115.38 mg/L. Mortality was observed. The 48–hr LC₅₀ was 44.66 mg/L, based on the nominal concentrations. 

This study is classified as acceptable and satisfies with the guidelines requirements for an acute toxicity study with freshwater invertebrates.

 

Marine species

Beside the key study, another data as available on marine invertebrates short term toxicity. The 96hr-acute toxicity of Arsenic acid toMysidopsis bahia was studied. Mysids were exposed to control, and test chemical at measured concentrations of 0.0 (control), 0.32, 0.63, 1.2, 1.7, 3.0, 5.2 and 9.0 mg a.i/L. Mortality and biological and physical effects were observed. The 96hr- LC₅₀ was 2 mg/L, based on the measured concentrations.

This study is classified as acceptable and satisfies with the guidelines requirements for an acute toxicity study with freshwater invertebrates.