Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Testing for toxicity to terrestrial organisms is not considered necessary because:

- The substance hydrolyses rapidly and its hydrolysis product has a Log KOW < 3, therefore, partitioning to the terrestrial compartment is expected to be minimal.

- The substance is used under highly controlled conditions and, therefore, exposure of soil is low.

- PNECsoil for the silanol hydrolysis product, trimethylsilanol, has been calculated from PNECaqua(freshwater) on the basis of the equilibrium partitioning method and the risk characterisation ratio (RCR) based on PNECsoil is <1 (see Section 10 of the CSR).

- Data are available for the toxicity of ammonia to terrestrial plants. Concentrations of ammonia in soil resulting from use of HMDZ are minimal compared to the natural background and other anthropogenic sources (see Section 9 of the CSR).

Toxicity of Ammonia:

The following results for terrestrial toxicity of ammonia are sourced from the OECD HPV Chemical Programme, SIDS Dossier Ammonia (CAS 7664 -41 -7) 2007.

The effects of ammonia gas was tested on terrestrial plant species.

4 hour LOECs for damage to leaf area ranged from 3 ppm to 40 ppm.

A 1 hour LC100 of 40 ppm was recorded for tomato and sunflower plants, where complete injury was caused.

High concentration tests from 4 to 8 minutes duration resulted in EC50s for foliar necrosis of 250 ppm NH3 (tomatos) to 1000 ppm NH3 (buckwheat and tobacco).

A 4 hour exposure to 1000 ppm NH3 killed moist spring rye seeds, whereas radish seeds were still viable after 16 hours. 250 ppm NH3 for 16 hours reduced rye seed germination by half, but had no effect on radish seeds.

Treatment of barley roots with 1.6x10-3M unionised ammonia reduced their respiration 23 percent and 3.3x10-3M unionised ammonia caused a 78 percent inhibition after 4 hours. The respiration of barley roots treated with 1x10-3to 3x10-3M unionised ammonia was reduced by 46 to 62 percent within 4 hours.

No data are available for toxicity to soil dwelling organisms.