Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

There are no reliable bioaccumulation studies for aquatic or terrestrial organisms for DMDMH. However, there is a reliable aquatic bioaccumulation study and an estimated aquatic BCF available for the hydrolysis product, DMH.   Due to the rapid hydrolysis of DMDMH to DMH the active substance would not be available for bioconcentration to occur therefore, exposure to the degradation product, DMH, is considered.

No reliable (Klimisch 1 or 2) bioaccumulation studies with fish have been conducted for DMDMH. A reliable (Klimisch 1) bioaccumulation toxicity study with fish has been conducted for DMH and is included in this dossier. The study Tunnell et al. (1991) provides a BCFfish of <1.79 and is not considered to be potentially bioaccumulative. Consequently this value will be taken as the BCF in fish endpoint for DMDMH. 

Due to an estimated BCFearthworm result of 0.087, calculated according to the Technical Guidance Document on Risk Assessment (TGD), Part II, DMH is not expected to accumulate in terrestrial biota. Furthermore DMH is readily biodegradable and has a high water solubility indicating a low potential for exposure to terrestrial organisms. The PEC/PNEC ratio for the terrestrial compartment has been calculated to be < 1 indicating that there is no cause for concern in terrestrial compartment. It is therefore considered that DMH would not bioconcentrate in terrestrial organisms based on this assessment. Therefore a test on terrestrial bioconcentration of DMDMH is scientifically unjustified.