1,1-dichloroethylene

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.009 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.091 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.001 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

2 000 mg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.08 mg/kg sediment dw

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.008 mg/kg sediment dw

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:

PNEC oral

PNEC value:

6 mg/kg food

Additional information

As stated in R7.8.5.3 of the Guidance on information requirements and chemical safety assessment chapter R.7b, the ecotoxicologic information should cover at least three thropic levels, i.e. algae/aquatic plants, invertebrates and fish. A first sequence of considerations is primarily based on the availability of short-term toxicity data.

 

Available short-term toxicity data:

 

Algae (Chlamydomonas reinhardtii):

According to the key study by Brack et al. (1994) with Chlamydomonas reinhardtii, the EC50 (72h) of 1,1 dichloroethene is 9.12 mg/l.

 

Invertebrates (Daphnia magna):

According to the key study according to OECD guideline 202 by Gancet (2010) the EC50 (48h) of 1,1-dichloroethene is 37 mg/l, the NOEC (48h) being 29.4 mg/l.

 

Fish (Pimephales promelas):

According to the key study by Dill et al. (1977) the LC50 (96h) of 1,1-dichloroethene is 107.9 mg/l.

 

Based on the data above, algae appear to be the most sensitive species, while fish appear to be the least sensitive. Relatively to the Chlamydomonas reinhardtii, Daphnia magna and Pimephales promelas appear to be about 4 and 12 times less sensitive to 1,1-dichloroethene respectively.

 

ThePNEC aqua (freshwater)was defined according to table R.10-4 of the Guidance on information requirements and chemical safety assessment chapter R.10, i.e. an assessment factor of 1000 was used for the most sensitive thropic level, i.e. algae.

 

ThePNEC aqua (marine water)was defined according to table R.10-5 of the Guidance on information requirements and chemical safety assessment chapter R.10, i.e. an assessment factor of 10000 was used for the most sensitive thropic level, i.e. algae.

 

As specified in R.10.3.3 of the Guidance on information requirements and chemical safety assessment chapter R.10, thePNEC_{water, intermittent}is normally derived by application of an assessment factor of 100 to the lowest L(E)C50 of at least three short-term tests from three thropic levels.

 

K_comp-water=Fair_comp*K_air-water+Fwater_comp+Fsolid_comp*(Kp_comp/1000)*RHOsolid (equation R.16-7)

where comp = sediment

K_susp-water=_susp*K_air-water+Fwater_susp+Fsolid_susp*(Kp_susp/1000)*RHOsolid

Fair_compnot relevant for sediment

K_sed-water= 2.1

 

Fwater_susp     = 0.9                         (m_water³*m_susp^-3)          (table R.16-9)

Fsolid_susp      = 0.1                         (m_solid³*m_susp^-3)          (table R.16-9)

Kp_susp            = Foc_susp* Koc = 0.1 * 52 = 2.2                 (equation R.16-6)

Foc_susp                       = 0.05                       (kg_oc*kg_solid^-1)            (table R.16-9)

Koc                = 52                                                             (IUCLID §5.4.1)

RHO_solid        = 2500                      (kg_solid*m_solid^-3)          (table R.16-9)

 

PNEC_sed= (K_susp-water/RHO_susp)*PNEC_water*1000             (equation R.10-2)

 

K_susp-water                                          =        2.2

RHO_susp                                            =        1150              (kg*m^-3)         (table R.16-11)

PNEC_water (freshwater)          =        0.00912                     (mg/l)             (IUCLID §6)

 PNEC_water (saltwater)            =        0.000912                  (mg/l)             (IUCLID §6)

 

PNEC_sed(freshwater)          = 0.0174 mg*kg^-1wet weight

PNEC_sed (saltwater)= 0.0017 mg*kg^-1wet weight

 

To obtain the PNECsed on a dry-weight basis, the following conversion factor is applied

 

CONV_susp         = RHO_susp/(Fsolid_susp*RHO_solid)

= 1150/(0.1*2500) = 4.6

 

=> PNEC_sed(freshwater) = 0.0174/CONV_susp= 0.080 mg/kg dry weight

 

=> PNEC_sed (marine water) = 0.0017/CONV_susp= 0.008 mg/kg dry weight

 

PNEC STP

Microbial inhibition test data is typically obtained from an activated sludge respiration inhibition assay.

Column 2 of Annex VIII mentions that the activated sludge respiration inhibition assay (9.1.4) does not need to be conducted if there are mitigating factors that microbial toxicity is unlikely to occur”. The high vapour pressure of 1,1-dichloroethene is a considered as such mitigating factor.

The protocol of the Activated sludge, Respiration Inhibition Test (OECD guideline 209) specifically mentions the importance of vapour pressure in the Qualifying statements, i. e. “This method is most readily applied to substances which, due to their water solubility and low volatility, are likely to remain in water.” Because of the high volatility of 1,1-dichloroethene, concentrations sufficient to elicit activated sludge respiration inhibition are most unlikely to occur.

Moreover, the protocol according OECD guideline 209 requires an active aeration (air flow of 0.5 to 1 l/min in a total mixture volume of 0.5 l during 3h). Such circumstances further increase the already important evaporation of 1,1-dichloroethene, quickly lowering the 1,1-dichloroethene concentrations tested. So similar as to the situation in a waste water treatment plant, the activity of 1,1-dichloroethene in the Activated Sludge, Respiration Inhibition Study can be considered primarily determined by its volatility resulting in a limited scientific value of the study.

The only relevant data (Pseudomonas putida, EC10 >2000 mg/l) originates from a secondary data source (handbook Verschueren et al, 1996). No verification of the original study is possible. This data source is nevertheless mentioned in table R.7.1.-2 of chapter R 7.1.1.2 of the Guidance on information requirements and chemical safety assessment.

Therefore 2000 mg/l is used as key value in the risk assessment. 

PNEC soil

Based on the expected low potential to adsorb to soil (log Koc=1.72) and the unlikeliness of direct and indirect exposure of the soil compartment, terrestrial toxicity testing is not considered required (column 2 of REACH Annex IX and X) and it is not considered relevant to derive a PNECsoil.

PNEC oral

Derivation of the PNEC oral was performed for sake of completeness because 1,1 -dichloroethene shows little potential for bioaccumulation.  

Equation R.10-7 was used to obtain the NOEC_{mammal, food_chr}, i.e.

NOEC_{mammal, food_chr}= NOAEL_{mamal, food_chr}* CONV_mammal[in kg.kgfood^-1] where

 

CONV_mammal= 20 (kg bw.d*kgfood^–1)       (Table R.10-12)

NOAEL_{mamal, food_chr}= 9 mg/kg= 9*10^-6kg/kg, a chronic oral rat study (Rampy et al. 1977, Quast et al.1983)

 

 NOEC_{mammal, food_chr}= 9*10^-6*20 = 1.8E-04 kg.*(kgfood^–1)

 

The PNEC_oralis calculated using equation R.10-8

PNEC_oral= TOX_oral/AF_oral where

 

TOX_oral= NOEC_{mammal, food_chr}= 1.8E-04 kg.*(kgfood^–1)

AF_oral= 30 (Table R.10-13)

 

 PNEC_oral=1.8E-04 kg*(kgfood^–1) /30= 6.0E-6 kg*(kgfood^–1)= 6 mg*(kgfood^–1)

 

 

 

Conclusion on classification

The following ecotoxicological information is available for 1,1-dichloroethene:

 

Fish: No reliable chronic data available. A non-standardized acute test in Pimephales promelas yielded a 72h-LC50 of 107.9 mg/L based on mortality and a 72h-EC50 of 72.9 mg/L based on behaviour. Extrapolation of these results towards the standard duration of 96h would result in an LC50 and an EC50 below 100 mg/L. Considering this outcome, and taking into account that the substance is not readily biodegradable leads to the conclusion that the substance is not to be classified for acute toxicity, and is assigned an Aquatic chronic toxicity Cat 3 for this trophic level.

 

Daphnia: No reliable chronic data available. An acute test in Daphnia magna yielded a 48h-EC50 of 37 mg/L based on mobility. Considering this outcome, and taking into account that the substance is not readily biodegradable leads to the conclusion that the substance is not to be classified for acute toxicity, and is assigned an Aquatic chronic toxicity Cat 3 for this trophic level.

 

Algae: In the available test on Chamydomonas reinhardtii, a 72h-EC50 of 9.12 mg/L (acute tox) and a 72h-EC10 of 3.94 mg/L (chronic tox) were determined. Taking into account the availability of acute as well as chronic data on algae leads to the conclusion that the substance is not to be classified for acute nor chronic toxicity.

 

In accordance with the criteria developed in ATP 2 to EU regulation 1272/2008 (CLP), the worst-case classification obtained among the different species is to be applied. In conclusion, 1,1-dichloroethene is classified as Aquatic Chronic Cat. 3.