Dichlorodifluoromethane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Non-GLP study; documented methodology and well conducted. Proposed acceptable for regulatory purposes.

Principles of method if other than guideline:

Test concentrations were prepared by adding 20 mL of dilution water as well as the daphnids to the test chamber. The vials were closed with a cap containing a Teflon-lined insert. A Teflon-gas bag containing R-12 was attached to the vial, and subsequently a volume of water was extracted from the vial with a syringe of the appropriate size. Thus, the volume of water extracted was replaced by a similar volume of R-12.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

A screening study was performed using nominal concentrations and a water control. The nominal concentrations were 0, 41, 72, 116, 169 and 217 mg/L.

Vehicle:

not specified

Details on test solutions:

Test concentrations were prepared by adding 20 mL of dilution water as well as the daphnids to the test chamber. The vials were closed with a cap containing a Teflon-lined insert. A Teflon-gas bag containing CFC-12 was attached to the vial, and subsequently a volume of water was extracted from the vial with a syringe of the appropriate size. Thus, the volume of water extracted was replaced by a similar volume of CFC-12.

Test organisms (species):

Daphnia magna

Details on test organisms:

Not specified

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observation period specified

Hardness:

Not specified

Test temperature:

Not specified

pH:

Not specified

Dissolved oxygen:

Not specified

Salinity:

Not specified

Nominal and measured concentrations:

The measured concentrations tested compared to the nominal concentration of 0, 41, 72, 116, 169 and 217 mg/L were 0.23 ± 1.2, 41 ± 3.1, 74 ± 2.0, 120 ± 7.2 and 155 ± 5.9 mg/L respectively.

Details on test conditions:

Test chambers were 20 mL scintillation vials containing appropriate dilution water. Five test chambers per concentration with five daphnids in each were used for the four highest concentration and four test chambers were used for the control and the lowest concentration.

Reference substance (positive control):

not specified

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

95 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The measured concentrations tested compared to the nominal concentration of 0, 41, 72, 116, 169 and 217 mg/L were 0.23 ± 1.2, 41 ± 3.1, 74 ± 2.0, 120 ± 7.2 and 155 ± 5.9 mg/L respectively. The percent immobility after 48 hours of exposure were 0, 0, 0, 16, 80 and 100% respectively. The 48 hour EC50 was 95 mg/L based on immobility and measured concentrations.
Table 1 (under Any other information) gives the calculated nominal aqueous concentration and average measured aqueous concentration of R-12 in the test chambers (± SD; n=5 for the four highest concentration and n=4 for the control and lowest concentration) at the end of the exposure (day 2).
The nominal and measured concentrations of R-12 are in general agreement, which indicates that the administration of gaseous R-12 to the vials was successful.

Results with reference substance (positive control):

Not specified

Reported statistics and error estimates:

Not specified

TABLE 1: Nominal aqueous concentration and average measured aqueous concentration of CFC-12 in the test chambers (± SD; n=5 for the four highest concentration and n=4 for the control and lowest concentration) at the end of the exposure (day 2).

Nominal concentration (ppm)	Measured concentration (ppm)	% immobility at 48 hrs
0	0	0
41	23±1.2	0
72	41±3.1	0
116	74±2.0	16
169	120±7.2	80
217	155±5.9	100

Validity criteria fulfilled:

yes

Conclusions:

The 48 hour EC50 was 95 mg/L based on immobility and measured concentrations.

Executive summary:

As the substance is a gas, the volatility of the substance precludes aquatic exposure.  Regulation (EC) No 2037/2000 of the European Parliament and of the Council of 29 June 2000 on substances that deplete the ozone layer lists within ANNEX I states that the substance is listed as a Group 1 substance. However, the registrant has a derogation in accordance with Regulation (EC) No 1005/2009 of the European Parliament and of the Council of 16 September 2009 on substances that deplete the ozone layer that allows for use of the substance as a processing agent. 

In accordance with the above two pieces of legislation, release is strictly controlled. As such, no release to the aquatic environment is envisaged. 

A screening study was performed using nominal concentrations and a water control. The nominal concentrations were 0, 41, 72, 116, 169 and 217 mg/L.

Test chambers were 20 mL scintillation vials containing appropriate dilution water. Five test chambers per concentration with five daphnids in each were used for the four highest concentration and four test chambers were used for the control and the lowest concentration.

Test concentrations were prepared by adding 20 mL of dilution water as well as the daphnids to the test chamber. The vials were closed with a cap containing a Teflon-lined insert. A Teflon-gas bag containing CFC-12 was attached to the vial, and subsequently a volume of water was extracted from the vial with a syringe of the appropriate size. Thus, the volume of water extracted was replaced by a similar volume of CFC-12. 

RESULT AND CONCLUSION

The measured concentrations tested compared to the nominal concentration of 0, 41, 72, 116, 169 and 217 mg/L were 0.23 ± 1.2, 41 ± 3.1, 74 ± 2.0, 120 ± 7.2 and 155 ± 5.9 mg/L respectively. The percent immobility after 48 hours of exposure were 0, 0, 0, 16, 80 and 100% respectively. The 48 hour EC50 was 95 mg/L based on immobility and measured concentrations. On the basis of this, it is proposed that the substance could potentially be hazardous to Daphnia.

 

The risk phrase: H412: Harmful to aquatic life with long lasting effects is applicable.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

January 2021

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE : ECOSAR V2.0

2. MODEL : organic module, class Neutral organics (Daphnia equation 2012)
Log LC50 (mmol/Log LC50 (mmol/L) = -0.8580 (log Kow) + 1.3848 , r2 = 0.7704

3. SMILES USED AS INPUT FOR THE MODEL: FC(F)(Cl)Cl

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF and/or QPRF

5. APPLICABILITY DOMAIN
- Descriptor domain: Maximum LogKow: 5.0, maximum MW: 1000
see attached documents

6. ADEQUACY OF THE RESULT
QSAR prediction for comparison purpose. The molecule falls within the applicability domain.

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

- Principle of test: Effects predicted using ECOSAR v2.00 for estimation of aquatic toxicity of chemicals
- Parameters predicted: daphnids LC50
By default the software assigns the substance to the class Neutral organics.

A first prediction was done using as input parameters the default LogKow estimated by the KOWWIN v1.67 software : 1.82, and experimental water solubility (280 mg/L)
A second prediction was done using as input parameters the identified experimental LogKow : 2.16, and experimental water solubility (280 mg/L)

GLP compliance:

no

Specific details on test material used for the study:

SMILES notation: FC(F)(Cl)Cl
water solubility used as input: 280 mg/L

Test organisms (species):

Daphnia sp.

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

41.1 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value.

Remarks:

prediction using estimated LogKow

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

81.2 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value.

Remarks:

prediction using experimental LogKow

Validity criteria fulfilled:

yes

Remarks:

the substance falls within the applicability domain of the model

Conclusions:

Assessment of the short-term toxicity to daphnia was conducted using ECOSAR v2.0 as a comparison to the experimental results.
The 48-hr LC50 was determined to be 81.2 mg/l using the estimated LogKow of 1.82 (as calulated by KOWWIN).
The 48-hr LC50 was determined to be 41.11 mg/l using the measured LogKow of 2.16
According to these results the substance could be harmful to Daphnia.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

January 2021

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction:
Validated QSAR calculation method. A validated QPRF is attached.

1. SOFTWARE : ISIDA Predictor developed by
Laboratoire De Chemoinformatique UMR 7140 CNRS, University of Strasbourg, Strasbourg, FR, 2019. (http://infochim.u-strasbg.fr/)

2. MODEL : ISIDA Consensus – Daphnia short-term toxicity (EC50) regression model, version October 2020

3. SMILES USED AS INPUT FOR THE MODEL : FC(F)(Cl)Cl

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL : details in attached QMRF
- defined endpoint: daphnia immobilisation

5. APPLICABILITY DOMAIN : details in attached QMRF.

6. ADEQUACY OF THE RESULT
The structure falled in the applicability domain of the 15 models. The prediction was considered optimal.

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

- Software tool(s) used including version: ISIDA Predictor (October 2020)
- Model(s) used: Regression model
- Model description: see QMRF in field 'Attached justification
- Justification of QSAR prediction: see QPRF in field 'Attached justification'

GLP compliance:

no

Specific details on test material used for the study:

SMILES notation: FC(F)(Cl)Cl

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

49.6 mg/L

Nominal / measured:

estimated

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value.

Validity criteria fulfilled:

yes

Remarks:

compound was within the applicability domain of all the individual models

Conclusions:

Daphnia 48-hr EC50 : 49.6 mg/l (sd: 0.06).
The substance could potentially be harmful to Daphnia.

Description of key information

Key value taken from experimental study on Daphnia Magna

EC50(48h): 95 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Remarks:

(48h)

Effect concentration:

ca. 95 mg/L

Additional information

For comparison purposes, additional assessments were conducted using valid QSARs for short-term toxicity to aquatic invertebrates

ECOSAR model v2.0: LC50 (48h) = 41.1 mg/l (with estimated LogKow) or 81.2 mg/l (with experimental LogKow)

ISIDA Predictor model: EC50 (48h) = 45.599 mg/l

 

Consistent QSAR determinations and experimental value support an EC50 between 10 and 100 mg/L, indicating the substance is potentially harmful to aquatic invertebrates.