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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

No reliable (Klimisch 1 or 2) bioaccumulation studies with fish have been conducted for DMDMH. However, two reliable (Klimisch 1 or 2) bioaccumulation toxicity studies with fish have been conducted for the hydrolysis product of DMDMH, DMH. Tunnell et al. (1991) provide a BCFfish of <1.79 and Dubas (2007) calculated a BCF of 0.08; these bioconcentration factors indicate DMH (and the parent substance DMDMH) are not considered to be potentially bioaccumulative. This measured value of <1.79 will be taken as the BCF in fish endpoint for DMDMH. 

Key value for chemical safety assessment

BCF (aquatic species):
1.79 dimensionless

Additional information

There are no reliable bioaccumulation studies for aquatic organisms for DMDMH. However, there is a reliable bioaccumulation study and an estimated 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.

Tunnell et al., (1991) conducted a reliable (Klimisch 1) GLP compliant bioaccumulation study following OECD 305E methods. Bluegill sunfish (Lepomis macrochirus) of average weight of 2.84 g, were exposed to one measured concentration (1 mg/L) of DMH, the hydrolysis degradation product of DMDMH, in a flow-through system. The concentrations of radioactivity in the water samples were converted to mg DMH equivalents/L of water. The uptake phase was for 28 days and the depuration phase was 14 days. Concentrations of radioactivity in edible and non-edible tissues of bluegill sunfish exposed to 14C-DMH at 1.0 ppm were lower than the limit of quantification therefore DMH did not bioconcentrate in fish tissue. The BCF is <1.79.

Dubas (2007) calculated a reliable (Klimisch 2) BCF value for fish of 0.08 for the hydrolysis product DMH, which was calculated based on the Kow value of -0.46 and the formula provided in the Technical Guidance Document on Risk Assessment (TGD), Part II. Based on the estimated BCF value of 0.08, DMH is not considered to be potentially bioaccumulative.

No reliable (Klimisch 1 or 2) bioaccumulation studies with fish have been conducted for DMDMH. However, two reliable (Klimisch 1 or 2) bioaccumulation toxicity studies with fish have been conducted for the hydrolysis product of DMDMH, 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 to be a more valid and realistic assessment. Tunnell et al. (1991) provide a BCFfish of <1.79 and Dubas (2007) calculated a BCF of 0.08; these bioconcentration factors indicate DMH (and the parent substance DMDMH) are not considered to be potentially bioaccumulative. This measured value of <1.79 will be taken as the BCF in fish endpoint for DMDMH.