2-(2-methoxyethoxy)ethanol

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

12 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

12 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1.2 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 000 mg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

44.4 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.44 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

2.1 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.09 g/kg food

Assessment factor:

200

Additional information

Derivation of assessment factor

There appear to be a number of reasons to deviate from the standard assessment factor of 1000 normally used when only 3 acute toxicity values are available. These are listed below:

• In addition to the base set of fish, daphnid and algae, there is data from a 4th trophic level (micro-organisms) available
• Data for several fish species are available.
• The substance shows a very low acute toxicity to water organisms (all EC50/LC50 values >1000mg/l), and in some species it is substantially higher.
• The substance acts by non-polar narcosis. This can be concluded from the observation that there is no significant difference between the LC50 values for fish, daphnia, algae and bacteria (all within an order of magnitude), which is typical of this category of substance. This is further supported by Bol et al (VROM, Netherlands, report 9A and 9B, 1993) who classified linear ethers on structural grounds as 'class 1 type compounds', i.e. thosethat show narcosis or baseline toxicity. Using the equations for non-polar narcosis (EU TGD 2005), ecotoxicity QSAR data can be estimated and are reasonably consistent with the experimental data.

Note that this assessment factor is consistent with that derived in the EU risk assessment for this substance (EU 1999).

Formula for the calculation of PNECsed using the equilibrium partitioning approach for sediment:

PNEC(sed) = (Ksusp-water x PNEC(aqua) / RHOsed) * 1000 - equation R.10 -2 of guidance

PNEC(sed) Predicted No Effect Concentration in sediment [mg/kg, wet weight]

Ksusp-water partition coefficient suspended matter / water [0.926 m3/m3] - equation R16 -13 of guidance

RHOsed bulk density of sediment matter [1150kg/m3] - equation R.10 -2 of guidance

PNECaqua Predicted No Effect Concentration in water [as above]

Formula for the calculation of PNECsoil using the equilibrium partitioning approach for soil:

PNEC(soil) = (Ksoil-water x PNEC(aqua) / RHOsoil) * 1000 - equation R10 -2 of guidance

PNEC(soil) Predicted No Effect Concentration in sediment [mg/kg, wet weight]

Ksoil-water partition coefficient sediment / water [0.306 m3/m3] - equation R16 -13 of guidance

RHOsoil bulk density of soil matter [1700 kg/m3] - calculated from composition information in table R16 -11 of guidance

PNECaqua Predicted No Effect Concentration in water [as above]

The PNEC oral is derived using the critical oral mammalian NOAEL (in mg/kg bw ) as a starting point. This is then converted to a NOEC (in mg/kg food) using the conversion factors in table R10-12 of the guidance from which the PNEC is derived by using the appropriate assessment factor in table R10 -13.

Conclusion on classification

The very low toxicity of 2 -(2 -methoxyethoxy)ethanol to aquatic species coupled with its ready biodegradability mean that it does not meet the criteria for classification.