Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
6.5 µg/L
Assessment factor:
3
Extrapolation method:
sensitivity distribution

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
3.4 µg/L
Assessment factor:
3
Extrapolation method:
sensitivity distribution

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
100 µg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
174 mg/kg sediment dw
Assessment factor:
3
Extrapolation method:
sensitivity distribution

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
164 mg/kg sediment dw
Assessment factor:
3
Extrapolation method:
sensitivity distribution

Hazard for air

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
147 mg/kg soil dw
Assessment factor:
2
Extrapolation method:
sensitivity distribution

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
10.9 mg/kg food
Assessment factor:
6

Additional information

Read-across approach for lead containing glass, oxide, chemicals:

The test item is covered under the definition "glass". In this context, “glass" is defined as an amorphous, inorganic, transparent, translucent or opaque substance formed by variouspowdery substances (mostly oxides) which are not present as such in the final glass: they are fully integrated into the glass matrix through the melting process and they lose their original characteristics. Thus, the available analytical information is only of quantitative nature without any indication as to elemental composition or structural purposes. Based on the definition under Regulation (EC) No 1907/2006, the test item fulfils the criteria for UVCB substances.

Substance-specific information for the test item glass, oxide, chemicals (water solubility < 100 mg/L) are not available. For this reason, read-across is anticipated to lead monoxide as a moderately soluble lead substance.

This read-across is considered justified and also conservative since lead monoxide (water solubility approx. 700 mg/L at 20°C) is one of the major starting materials (content ranging from approx. 30-80%) for the test item manufacture, and also represents the component of major toxicological concern.

For the substantiation of read-across, solubility tests (T/D and bioaccessibility) were performed with the test item in order to determine the release of lead from the “glass” matrix for a comparison to the solubility of the selected read-across substance.

The following lead concentrations were measured in two T/D tests with the test item with variable lead monoxide concentrations (starting material concentration):

Test material with a PbO content of 38.4%:

After 7 days, the dissolution of Pb ranged from 17.0 ± 1.99 µg/L (pH 8) to 18.7 ± 2.08 µg/L (pH 6).

After 28 days, the dissolution of Pb ranged from 37.8 ± 3.64 µg/L (pH 8) to 60.1 ± 17.2 µg/L (pH 6).

Based on the nominal test item amount, the maximum dissolution of Pb at pH 6 from the test item corresponded to 6.01% (w/w); based on contained lead 5.95% (w/w).

At pH 8, the maximum dissolution of Pb after 24 h based on contained Pb was 3.68 µg/L (1.03% (w/w)).

Test material with a PbO content of 78.0%:

After 7 days, the dissolution of Pb ranged from 53.8 ± 8.53 µg/L (pH 8) to 562 ± 86.1 µg/L (pH 6).

After 28 days, the dissolution of Pb ranged from 110 ± 8.28 µg/L (pH 8) to 684 ± 22.8 µg/L (pH 6).

At pH 6, the maximum dissolution of Pb from the test item was 68.4% (w/w) based on nominal test item loading. Based on contained Pb, the dissolution corresponded to 94.3 % (w/w).

At pH 8, the maximum dissolution of Pb after 24 h based on contained Pb was 29.4 µg/L (4.06 % (w/w)).

In comparison, a water solubility of lead monoxide (saturation solubility, OECD 105; Heintze 2005) of is given with 70.2 mg/L in the REACH registration dossier and in the "Voluntary Risk Assessment for Lead and Lead Compounds"; a T/D screening test at pH = 8 with a 100 mg/L loading revealed an average (+- SD) dissolved Pb concentration after 24 hours of 101 (+-0.003) µg/L.

Based on the above data, the release of Pb fromthe test item glass, oxide, chemicals is substantial, but eithersimilar or lower compared to pure PbO. Thus, read-across to lead monoxide can be considered scientifically justified and sufficiently conservative.

Discussion:

In assessing the ecotoxicity of metals in the various environmental compartments (aquatic, terrestrial and sediment), it is assumed that toxicity is not controlled by the total concentration of a metal, but by the bioavailable form. For metals, this bioavailable form is generally accepted to be the free metal-ion in solution. In the absence of speciation data and as a conservative approximation, it can also be assumed that the total soluble lead pool is bioavailable. All reliable data on ecotoxicity and environmental fate and behaviour of lead and lead substances were therefore selected based on soluble Pb salts or measured (dissolved) Pb concentration.

 

The reliable ecotoxicity data selected for effects assessment of Pb in the various environmental compartments are derived from tests with soluble Pb salts (lead (di)nitrate, lead carbonate, lead acetate, lead chloride). Since lead is the toxic component and the anions do not contribute to toxicity, all reliable data are grouped together in a read-across approach and the PNEC’s are expressed as μg Pb/L (measured dissolved concentration) or mg Pb/kg. These results can be used for all other Pb compounds without concern on toxicity of the anions.

 

Conclusion on classification

Lead monoxide:

A TDp 24 h screening test is available for Lead oxide although limited to pH8 information. Given the lower acute toxicity reference values at pH6 (79,4 µg/l) and pH7 (56,1 µg/l) and the expected higher solubility at this pH (> 100 µg/l), it can be deduced/concluded that with the information available, PbO would fail the 24h screening test and should therefore be classified as the soluble Pb ion, corrected for molecular weight, being :

· Under DSD : R50/53, with an M factor of 10

· Under CLP : Acute 1 – Chronic 1, with an M factor of 10

In line with annex 4 chapter IV.5.3 of the CLP, Metal compounds must be classified by comparing Transformation Dissolution data with toxicity date for the soluble metal ion. The availability of toxicity information on the soluble ion (developed under the Lead metal registration file) makes the requirement for aquatic ecotoxicity tests on Lead oxide redundant.

Transformation Dissolution data in accordance to the OECD protocol are available for Lead oxide but to a limited extend (24h screening test at pH 8 only). There is therefore no absolute need for further developing Transformation Dissolution data on Lead-oxide given a default classification of R50-53 or Acute 1-Chronic 1, could be derived

It is however noted that due to the default nature of this assessment that further Transformation Dissolution testing on the compound has the potential to alter the classification to a lower classification category.

Inorganic glass, oxide, chemicals:

The following results from the T/D tests for the two glass samples were received:

Test material with a PbO content of 38.4%:

After 7 days, the dissolution of Pb ranged from 17.0 ± 1.99 µg/L (pH 8) to 18.7 ± 2.08 µg/L (pH 6).

After 28 days, the dissolution of Pb ranged from 37.8 ± 3.64 µg/L (pH 8) to 60.1 ± 17.2 µg/L (pH 6).

Based on the nominal test item amount, the maximum dissolution of Pb at pH 6 from the test item corresponded to 6.01% (w/w); based on contained lead 5.95% (w/w).

Test material with a PbO content of 78.0%:

After 7 days, the dissolution of Pb ranged from 53.8 ± 8.53 µg/L (pH 8) to 562 ± 86.1 µg/L (pH 6).

After 28 days, the dissolution of Pb ranged from 110 ± 8.28 µg/L (pH 8) to 684 ± 22.8 µg/L (pH 6).

At pH 6, the maximum dissolution of Pb from the test item was 68.4% (w/w) based on nominal test item loading. Based on contained Pb, the dissolution corresponded to 94.3 % (w/w).

Based on these results, classification for environmental toxicity shall be similar to lead monoxide:

- Under DSD : R50/53, with an M factor of 10

- Under CLP : Acute 1 – Chronic 1, with an M factor of 10