Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability:

Study on hydrolysis waived due to the extremely poor water solubility of the test item of 0.027 mg/L.

Biodegradation:

Both a study on anaerobic biodegradability and a study on (aerobic) inherent biodegradability revealed that the substance is not biodegradable.

Ultimate degradation in surface water (OECD 309)

The half-life, DT50, of the parent compound in natural water was determined to be 11.9 days at high dose (0.015 mg/L) and 11.2 days at low dose (0.005 mg/L). Under sterile conditions the parent compound degraded slower than in non-sterile conditions. The half-life was 60.2 days at a concentration of 0.015 mg/L. The parent compound degraded to two major metabolites, depending on the placement of the radiolabel and a common metabolite for both labels.

Biodegradation in sediment (OECD 308)

The half-life, DT50, of the parent compound in freshwater sediment was determined to be 124 days at 12 °C in a river water/sediment system. The half-life in the river water phase was 3.5 days at 12 °C and from the entire river water/sediment system the DT50 was determined to be 83 days at 12 °C.

Using a pond water/sediment system, the DT50 for the parent compound in the sediment phase was 152 days at 12 °C, for the pond water phase 2.4 days at 12 °C and for the entire pond water/sediment system, the DT50 was 113 days at 12 °C.

Bioaccumulation:

It is concluded from experimental results obtained from a fish dietary bioaccumulation study with rainbow trout that BMDBM is taken up by rainbow trout up to a certain extent resulting to a lipid normalized BMF which is far below 1 (BMF Lipid = 0.1218). BMDBM was eliminated from rainbow trout with a half-life of 3.83 days. These results indicate that the bioaccumulation and biomagnification potential is low.

Transport and distribution:

The computational approach (QSPR) for deriving the Koc is based on the real physical properties of the test item, i.e. the experimentally derived log Kow of 6.1. When using the geometric mean of the results of four different QSPR models, the resulting log Koc is 4.65 (Koc = 44242 L/kg). Based on this result BMDBM has to be considered as "immobile" in sediments or soil.