Copper(2+) tetrafluoroborate(1-)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

7.8 µg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

5.2 µg/L

Assessment factor:

1

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

230 µg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

87 mg/kg sediment dw

Assessment factor:

1

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

676 mg/kg sediment dw

Assessment factor:

1

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:

65 mg/kg soil dw

Assessment factor:

1

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The environmental fate and ecotoxicity data retained for the classification and labeling of copper compounds and for the Hazard classification and PNEC derivation under the copper RA (discussed by the Competent Authorities for EU Classification and labeling, Existing Substance Regulation and Biocidal Products Directive) form the back-bone for the classification and PNEC derivations of copper and copper compounds under REACH. 

The approach, data-selection, the use of the bio-availability models and derivation of "reasonable worst case" PNECS, for EU surface waters, sediments, soils are based on the copper Risk Assessment Report, discussed and agreed at the level of the competent Authorities for Biocides and Existing Substance Regulations.

Some modification have been made

- The CLP guidnace was adopted. The CLP guideline allows to incorporate “removal from the water-column” as surrogate to the biodegradation used for organic substances and this has been incorporated into the revised classification of copper powders.

- SCHER provided additional recommendations and the most important ones have integrated into the IUCLID/:

* the refinement of the marine PNEC with a marine mesocosm study. The marine mesocosm record is available (Foekema et al, 2010) in section additional ecotoxicological information) . The revised marine PNEC derivation is described in the CSR - aquatic PNEC derivation

* the refinement of the "reasonable worst case PNEC " for soils, including a more extensive assessment of the soil chemistry. The revised terrestrial PNEC derivation based on extensuve EU soil chemistry is available from Oorts et al, 2010, attached to the summary record on terrestrial toxicity.

The "reasonable worst case PNECs" were carried forward to the risk characterisation and used as default values in absence of detailed information on the chemistry of the surface waters, sediment, soil. The summaries of the PNEC derivations for water, sediment and soil are available from the CSR.

Tge vakues for the HBF4 (for the BF4 anion) are not relevant for assessemnt of this endpoint, neaucse of EC50 / NOEC > 1000 mg/L

Conclusion on classification

Environmental classification justification

The ecotoxicity database and reference values, agreed by the EU classification and labelling group and used for the ANNEX IV entries have been largely retained.

For the environmental classification of copper metal, the reference effects data obtained with soluble copper compounds (section ecotoxicity) are compared to the copper releases as observed from transformation/dissolution tests (section environmental fate).

1. For massive copper materials, seven days transformation/dissolution tests were carried out at pH 6, 7 and 8 demonstrated a higher copper release rate at lower pHs.  Abrasion of the massive material was demonstrated and additional tests were carried out with non-abrasion devices. The results are compared with the reference effects data obtained with soluble copper compounds.

At pH 6, the copper release in an abrasive test set-up from 100mg Cu/l (77 µg Cu/L) at pH 6 (highest release) is somewhat higher then the reference L(E) 50 (25 µg Cu/L) obtained between pH 5.5 and 6.5.

The non-abrasive release after 7 days at a loading of 100 mg/L at pH 6 (7.6 µg Cu/l) is however lower then the reference L(E) 50 (25 µg Cu/L) obtained between pH 5.5 and 6.5.   

Also the release after 28 days at a loading of 1 mg/L at pH 6 is lower then the chronic NOEC (20 µg Cu/L) obtained between pH 5.5 and 6.5.

The data therefore demonstrate that there is no need to classify copper in its massive form.

 

2. For Copper powders,transformation/dissolution tests were carried out on fine copper powders (<160µm, 106 mm2/g, some Cu₂0 presence) in accordance to Annex 10, GHS guidance (Skeaff and Hardy, 2005 – record in section “additional information on environmental fate”.

The release of copper to the aqueous medium at 7 days for the 100 mg/L loading at pH 6 was 1118µg/L. For the 1 mg/L loading, the average value of Cu(aq) at 7 days was 82µg/L at pH 6.  

The effect of the superficial oxidation film and of abrasion on the T/D behaviour of the copper powder is uncertain.

The release after 7 days (82 µg Cu/L) at pH 6 and 1mg/L is higher then the reference L(E) C50 (25 µg Cu/L) obtained between pH 5.5 and 6.5.  From these data, a hazard quotient of 3.2 can be calculated for the 1 mg/L loading. .   A classification as R50 (DSD) or acute 1 (GHS) is therefore needed. From a hazard quotient of 3.2 at a loading of 1 mg/L it is reasonable to assume that a hazard quotient below 1 will be observed at a ten times lower loading ( loading of 0.1 mg/L) and consequently an M factor of 1 is deducted for copper powder, 

The data therefore demonstrate the need to classify copper powder as R50 (DSD) and acute 1 (GHS)

In absence of data on “removal from the water-column” a proposal as R50/R53 (DSD) or Chronic 1 (GHS), M factor 1 was therefore concluded in the RA report.

Refined chronic classification for copper powder

Copper powder is classified as R50, because the released copper concentrations from T/D at a loading of 1 mg copper powder/L are larger then the L(E) C50 of the soluble ions. The chronic classification (R53) is actually automatically assigned because NOEC/ L(E) C10 values are always lower then L(E) C50 values.

Considering theCLP(2009) guidance, metal-specific annex, the chronic classification entry can now be refined using the information on bio-accumulation and environmental fate and behaviour (removal from the water column).  

Bio-accumulation

 TheCLPguidance (2009) mentions:

 “BCFand BAF may be used to estimate metal accumulation:

a)     consider information on essentiality and homeostasis of metals/ metal compounds. Metals that are essential nutrients are actively regulated: removal and sequestration processes that minimise toxicity are complemented by an ability to up-regulate concentrations for essentiality. As a result, of such regulation, the “bioaccumulative” criterion is not applicable to these metals. “

Copper is an essential nutrient and all living organisms have well developed mechanisms for regulating copper intake, copper elimination and internal copper binding. The information in the “accumulation” section of the IUCLID andCSRdemonstrates that copper is well regulated in all living organisms and that highestBCF/ BAF values are noted when copper concentrations in water, sediments and soils are low and for organisms/ life stages with high nutritional needs. TheBCF/ BAF values therefore have no ecological meaning.

The “bioaccumulative” criterion is therefore not applicable to copper and copper compounds

Removal from water column

Information on “rapid removal from the water-column was assessed following theCLPguidance

“The use of laboratory mesocosm and/or field tests for evaluating removal of soluble metal species through precipitation/partitioning processes over a range of environmentally relevant conditions are described in the guidance”

A desk study, aiming at evaluating, from model simulations and from laboratory mesocosm and field tests, the removal of soluble copper species through precipitation/partitioning processes over a range of environmentally relevant conditions, was performed. The details of the assessment are provided in the study-record: Rader et al, 20120- see section “additional information on environmental fate”. 

The main conclusions are formulated as follows:

·       For a standard lake environment consisting of the EUSES model lake parameters and the Kd derived in the copper RA (Log Kd: 4.48), copper removal from the water column satisfies the definition for rapid removal of 70% dissolved copper removal in 28 days;

·       For a standard lake environment consisting of the EUSES model lake parameters (pH varied between 6 and 8), copper removal from the water column satisfies the definition for rapid removal of 70% dissolved copper removal in 28 days;

·       For an experimental freshwater mesocosm study, carried out with a range of copper loadings (Schaefers et al, 2003), the measured data demonstrate a half life of 4 days and thus satisfy rapid removal of copper (i. e. greater than 70% in 28 days);

 ·       For the whole-lake spike addition studies (Lake Courtille and Saint Germain les Belles Reservoir), TICKET-UWM results, in concert with the measured data, indicate rapid removal of copper (i. e. greater than 70% in 28 days) for both lake systems;

·       Hypothetical TICKET-UWM simulations modelling the removal of copper in the MELIMEX limno-corrals following termination of copper loading demonstrate copper removal that does not meet the rapid removal benchmark because of a low settling velocity, low distribution coefficient, and low suspended solids concentration.  

Considering that the MILIMEX system is the only scenario that could not demonstrate “rapid removal” it is critical to assess the environmental relevance of the MILIMEX system.  The MILIMEX System was characterised by a setting velocity that is 10 times lower then the one in the EUSES system (0.2 versus 2.5 m/d)  and a suspended solid concentration that is almost 3 times lower then the EUSES system (5.9 versus 16 mg/L).  It is therefore concluded that the MILIMEX study was carried out under extreme conditions.

It can therefore be concluded that under “environmental relevant “conditions, copper-ions are rapidly removed from the water-column.  

Absence of remobilization from the sediment compartment

In the sediment compartment, copper binds to the sediment organic carbon (particulate and dissolved) and to the anaerobic sulphides, resulting in the formation of CuS. CuS has a very low stability constants/solubility limit (LogK=-41 (Di Toro et al.,1990) – see sectionadsorption/desorption) and therefore the “insoluble” CuS keeps copper in the anaerobic sediment layers, limiting the potential for remobilization of Cu-ions into the water column.

Simpson et al (1998), Sundelin and Erikson (2001) and Buykx et al (2000) (see sectionadsorption/desorption)provide field evidence on the stability of the CuS binding.

Last but not least, the assessment of 2 field experiments with intermittent copper dosing (LakeCourtille and the Saint Germain les Belles Reservoir lakes, yearly dosed with copper), assessed in Rader et al, 2010, provides further support for the absence of re-mobilization. Since both water bodies are shallow, polymictic lakes, wind-driven resuspension is expected to play a role in copper dynamics in the water column. Nevertheless, even if long-term resuspension does in fact occur, for both water bodies, > 70% removal in less then 28 days was observed. The information therefore validates the results from the model simulations and absence of remobilization from the water column (Rader et al. 2010).

It can therefore be concluded that CuS complexes are stable and remobilization of Cu-ions to the water-column is not expected.

The “persistence” criterion is therefore not applicable to copper and copper compounds

Conclusion on the classification of copper powder

- Copper is an essential nutrient for which the bio-accumulation criterion does not apply

- Copper ions are rapidly removed from the water column and the removal rate under relevant conditions is >70% within 28 days

- Copper is strongly bound to the sediment sulphides and the oxidation rate of CuS is low, limiting remobilization of copper during re-suspension. 

Considering this weight of evidence, it is proposed to remove the chronic classification entry for copper.  

A classification of copper powder as R50 (M factor 1) is proposed under the DSD. A classification of copper powder as Acute 1 (M factor 1) is therefore proposed under the GHS.

3. For Coated copper flakes,no specific assessment has been done and read-across from copper powders is proposed.

R50 (M factor 1)under the DSD and Acute 1 (M factor 1) under the GHS.

See attachment below "Van Sprang_2010.