Norflurane

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.1 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.01 mg/L

Assessment factor:

10 000

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

73 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.75 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

no exposure of sediment expected

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no exposure of soil expected

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The aquatic PNECS were estimated by considering the lowest value obtained in the aquatic toxicity tests (estimated EC50 > 100 mg/l for algae) and dividing it by the default assessment factors of 1000 for fresh water and 10 000 for marine water. The measured EC50 for Daphnia and LC50 for trout of 980 and 450 mg / l respectively are indicative of the low aquatic toxicity of HFC 134a and the estimated value for algae is anticipated to be conservative.

Further, there are no plausible mechanisms to release HFC 134a from its use as a product into water without instant vaporisation due to its boiling point of -26°C. The solubility of 1g/l for a saturated solution can only occur when water is in equilibrium with 1 atmosphere pressure of HFC 134a. This cannot occur in practice for unconfined releases. The concentration in water depends on the partial pressure of HFC 134a in contact with the water. The current atmospheric concentration of HFC 134a is about 55 picomol/mol. At equilibrium the concentration of HFC 134a in water in contact with the atmosphere can be no higher than 55 picograms/litre. The measured concentration from manufacturing of HFC 134a for aqueous discharge to freshwater is 0.00188 mg/litre, well below the PNEC for freshwater of 0.1mg/l. This is without allowing for any further vaporisation losses of HFC 134a from the water.

With respect to sediment toxicity, the PNEC was estimated via the Equilibrium partitioning method (Guidance IR&CSA, R.10). The estimated Koc of 37.26 l/kg (5.4.1) was used for the estimation of the sediment-water partition coefficient Kp-sed in the equation:

Kp-sed = 0.05 x Koc = 1.86 l/kg

Ksed-water was calculated by the equation:

Ksed-water = Fwater-sed + {F soil-sed x (Kp-sed x 2.5)}

= 0.8 + {0.2 x (1.86 x 2.5} = 1.73

and this value is used for the PNEC estimation in the following equation:

PNECsed = (Ksed-water / 1.15) x PNECwater

= (1.73 / 1.15) x 0.1

Therefore PNECsed = 0.15 mg/kg w.wt for fresh water. These PNEC values are converted to the values for dry weight sediment by dividing by the fraction of solid in the sediments (0.2) to give the reported PNECS:

PNEC sediment (freshwater) = 0.75 mg/l

STP: no emission to STP is expected. However the PNEC is anticipated to be 73 mg/l from applying a assessment factor of 10 is applied to the measured EC 50 bacteria (Pseudomonas putida) of >730 mg/l.

Terrestrial toxicity: No direct for indirect exposure to HFC 134a is expected for terrestrial organisms. Therefore PNEC derivation is not necessary.

Oral (secondary poisoning): due to the very low bioaccumulation potential of HFC 134a, no secondary poisoning is expected. PNEC derivation is not necessary.

Conclusion on classification

EU and GHS hazard classification

The acute toxicity of HFC 134a to aquatic organisms is low: the measured EC50 is 980mg/l for Daphnia, the LC50 for trout is

450 mg/l and the estimated EC50 for algae is > 100 mg/l.

Although practically no biodegradation has been observed (2 to 3% after 28 days in a Closed Bottle Test) the high volatility and low bioaccumulation potential of HFC 134a make any impact on the aquatic enviroment unlikely. As HFC 134a does not contain Chlorine or Bromine, it is not classifiable as dangerous for the ozone layer. In conclusion, the substance does not need to be classified as Dangerous for the Environment according to EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) N0. 1272/2008.

Preliminary PBT Assessment

An assessment of the PBT status of 1,1,1,2-Tetrafluoroethane (HFC 134a) has been made using all available data. The information available suggests that HFC 134a does not meet the screening criteria as outlined in Directive 2006/121 EC (See Appendix A for the criteria).

Persistence

A Closed Bottle Test (OECD 301D) showed that HFC 134a is not readily biodegradable in aquatic media. However, HFC 134a is a gas of low solubility and when released to the environment will enter almost exclusively into the ambient air. It has little tendency to partition to biota or soil. Because of its moderate sorption affinity, HFC 134a is expected to be mobile in soil. The most important degradation process occurs in the atmospheric compartment. Consequently HFC 134a will not be persistent in the aquatic environment.

Bioaccumulation

No bioconcentration test is available. However, as the log Kow is 1.06 bioaccumulation is not expected. HFC 134a is therefore considered not bioaccumulative.

Toxicity

The measured acute effect concentrations are much higher than the screening criterion of 0.1 mg/l. It can therefore be expected that HFC 134a is not toxic towards aquatic organisms. The chronic effect concentrations for invertebrates and fish are likely to be much higher than the definite criterion of 0.01 mg/l. HFC 134a is not classified as being a CMR and there is no evidence that it is chronically toxic towards mammals. Therefore HFC 134a is not assigned as toxic.

The overall conclusions, based on the present available data, of the preliminary PBT assessment are that the (screening) criteria for PBT / vPvB are not met and that further testing in the scope of the final PBT assessment is not considered to be required.