Germanium hydroxide oxides, amorphous silica and sodium chloride, recovery products from germanium refining

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

43.4 µg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

43.4 µg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

7 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

599.4 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

19.6 mg/kg sediment dw

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:

43.4 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Conclusion on classification

Ecotoxicity tests were performed with GeO2 as test substance. From the data, the ecotoxicity reference values (ERV's) for acute and chronic toxicity of GeO2 and of the Ge-ion in general, were derived.

acute effect:

the lowest EC50 value of 0.206mg GeO2 /L was observed on the freshwater diatomea Navicula pelliculosa, in a standard OECD 201 algae test (Fraunhofer 2017). From this result, a general EC50-based ERV of 0.143mg Ge/L can be derived for the Ge-ion.

Based on this ERV, GeO2 is classified as acute 1 for aquatic effect.

chronic effect:

the lowest EC10 value of 0.1003 mg GeO2/L was also observed on the freshwater diatomea Navicula pelliculosa, in a standard OECD 201 algae test (Fraunhofer 2017). From this result, a general EC10 -based ERV of 0.07 mg Ge/L can be derived for the Ge-ion.

To define the chronic classification, it must be established whether or not the substance can be considered to be (equivalent to) rapidly degradable or not. To answer this question, the concept of "removal from the water column" has been developed for the metal substances. To check the presence of the metal -ion in the water column, (and its related potential chronic toxicity), metal concentration in a water column is followed over a given time under experimental conditions. The results on GeO2 demonstrate that Ge removal from the water column is 80% after 4 weeks . Resuspension of the sediment in the experimental volume does not result in remobilisation of Ge into the water column. Based on these results, it is concluded that Ge and its salts are to be considered as equivalent to rapidly degradable in the water column.

Based on the ERV of 100.3 µg/l, and considering the substance as equivalent to rapidly degradable, GeO2 is classified as "chronic 3 for aquatic effect".