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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.19 µg/L
Assessment factor:
2
Extrapolation method:
sensitivity distribution

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
1.14 µg/L
Assessment factor:
2
Extrapolation method:
sensitivity distribution

STP

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

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
1.8 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.64 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
equilibrium partitioning method

Hazard for air

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
0.9 mg/kg soil dw
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
0.16 mg/kg food
Assessment factor:
10

Additional information

A basic assumption made in this hazard assessment and throughout this CSR, (in accordance to the same assumption made in the EU RA process) is that the ecotoxicity of cadmium and cadmium compounds is due to the Cd++ion. As a consequence, all aquatic, sediment and terrestrial toxicity data in this report are expressed as “cadmium”, not as the test compound as such, because ionic cadmium is considered to be the causative factor for toxicity. A further consequence of this is that all ecotoxicity data obtained on different cadmium compounds, are mutually relevant for each other. For that reason, the available ecotoxicity databases related to cadmium and the different cadmium compounds are combined before calculating the PNECs. The only way cadmium compounds can differ in this respect is in their capacity to release cadmium ions into (environmental) solution. That effect is checked eventually in the transformation/dissolution tests and may result in different classifications.

Conclusion on classification

The classification of Cadmium metal and sparingly soluble Cd-compounds is based on the capacity of these substances to release the Cd++ ion in standardized solutions (= “transformation/dissolution test -T/D test - OECD 2001). The Cd++ release measured after a given time (7d for acute effects, 28days for chronic effects) is compared to the ecotoxicity reference values for acute, and chronic aquatic effects, i.e.: 18 µg Cd/l and 0.210 µg Cd/l, resp. (ECB 2007).

Classification under Annex I dangerous substances directive 67/548/EEC

CdS powder was classified R53 (may cause long-term adverse effects in the aquatic environment); cfr Annex I of the dangerous substances directive 67/548/EEC).

 

Classification under Annex VI of the EU CLP regulation

The classification listed in Annex I to Directive 67/548/EEC was translated as Aquatic Chronic 4, H413 (May cause long lasting harmful effects to aquatic life) according to Annex VI of the EU CLP Regulation (EU 2008).

 

Further considerations referring to 2nd Adaptation to Technical Progress (ATP) to the CLP Regulation (2nd ATP CLP) based on recent information

Transformation/dissolution tests have been performed on fine CdS powder (ECTX 2010) at 1 mg/l loading , pH 6 (worst case). After 7days, 2.71µg/l Cd was released from the CdS; after 28 days, 5.75 µg Cd/l was released. Based on these data, the following classification can be derived based on the2ndATP CLPrules:

-acute aquatic effects: at 1mg/l loading of the finest powder on the EU market, the release of Cd++ ions after 7days (0.0027mg/l) was not exceeding the reference value for acute ecotoxicity (18µg/l).Therefore CdS powder should not be classified for acute aquatic effect (this corresponds with the Annex VI classification).

 

-chronic aquatic effects:at 1mg/l loading of the CdS powder, the release of Cd++ ions after 28 days was 0.0058 mg/l. Extrapolating these data to the loading criteria under2ndATP of the CLP, the Cd++-release at 100 µg/l and 10 µg/l loading can be calculated as being 0.58 µg/l and 0.058 µg/l, resp. So, the reference value for chronic aquatic effects (0.210µg/l) is exceeded at 100µg/l loading, but not at 10µg/l loading.

For defining the reference loading criterion for chronic aquatic effect, the “degradability” needs to be determined. Cadmium, like all metals, is an element, and therefore the criterion “degradability” cannot be applied as it is for organic substances. As a surrogate for assessing “degradability”, the concept of “removal from the water column” was developed to assess whether or not a given metal ion would remain present in the water column upon addition (and thus be able to excert a chronic effect) or would be rapidly removed from the water column. In this concept, “rapid removal” (defined as >70% removal within 28 days) is considered as equivalent to “rapidly degradable”. Under section 4.6., the rapid removal of Cadmium from the water column is documented. Consequently, the metal is considered as equivalent to being ‘rapidly degradable” in the context of classification for chronic aquatic effects. 

Considering the above, it can be concluded that CdS is to be classified Chronic 2, H411(Toxic to aquatic life with long lasting effects). 

Since such ‘chronic 2’ classification is stronger then the existing ‘chronic 4’ classification (Annex VI CLP), it is proposed to replace the Annex VI classification ‘chronic 4’ by a classification as “chronic 2” (2ndATP CLP).

 

General discussion

A basic assumption made in this hazard assessment and throughout this CSR, (in accordance to the same assumption made in the EU RA process) is that the ecotoxicity of cadmium and cadmium compounds is due to the Cd++ion. As a consequence, all aquatic, sediment and terrestrial toxicity data in this report are expressed as “cadmium”, not as the test compound as such, because ionic cadmium is considered to be the causative factor for toxicity. A further consequence of this is that all ecotoxicity data obtained on different cadmium compounds, are mutually relevant for each other. For that reason, the available ecotoxicity databases related to cadmium and the different cadmium compounds are combined before calculating the PNECs.

The only way cadmium compounds can differ in this respect is in their capacity to release cadmium ions into (environmental) solution. That effect is checked eventually in the transformation/dissolution tests and may result in different classifications (see above).