1,3,2-dioxathiolane 2,2-dioxide

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with Column 2 of Annex IX section 9.4.1 of REACH, short-term toxicity testing to terrestrial invertebrates (soil macroorganisms) need not be conducted if direct and indirect exposure of the soil compartment is unlikely.

No direct exposure of the soil compartment is anticipated based on uses of the substance and from waste disposal from industrial use sites - no substance is expected to be applied directly to soil.

Indirect expsoure of soil compartment is considered unlikely. Readily biodegradable substances which are not directly applied to soil are generally assumed not to enter the terrestrial environment and as such there is no need for testing of soil organisms. The substance is not identified as readily biodegradable. However, hydrolysis of the substance has been identified as the main route of degradation (abiotic). Results of an hydrolysis as function of pH study (OECD) showed the estimated half-life of the substance at 25°C to be less than 2 minutes at pH 4, 7 and 9. In addiiton, the hydrolysis study proposed the hydrolysis product to be Hydroxyethyl sulphate and this hydrolysis product is predicted to be readily biodegradable using EPISUITE model BIOWIN v4.10. It is therefore assumed that the parent substance or hydrolysis product are unlikely to enter the terrestrial environment.

The substances low log octanol/water partition coefficient (Log Pow -045) indicates that the substance will predominately stay in the aquatic environment if released. The low adsorption coefficient of log Koc <1.25 indicates the substance has low potential for adsorption to soil (or sediments) and is therefore not likely to partition into the soil compartment and accumulate in the terrestrial compartment. Exposure to soil macroorganisms through ingestion of soil particles will therefore be very limited. The hydrolysis product is also expected to have low potential for adsorption to soils (predicted log Pow -3.95 and log Koc <1).

In the absence of toxicity data for soil organisms, the Equilibrium Partitioning Method may be applied to assess the hazard to soil organisms. However, as no hazard was identified in acute toxicity studies in fish, Daphnia and algae, the equilibrium partitioning method is not considered likely to provide further useful additional information.

As further support, a prediction using EPISUITE model ECOSAR (v 1.11) on the substance gave a predicted Earthworm 14-day LC50 of 9974 mg/L, indicating that the substance is unlikey to show significant toxicity towards terrestrial organisms in the event of exposure.

Based on the above, a short-term toxicity test to soil macroorganisms (invertebrates) except arthropods is not considered to be necessary.