Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

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

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.86 µg/L
Assessment factor:
10
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
0.025 mg/L
Assessment factor:
1
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
438.13 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
438.13 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
assessment factor

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
1.41 mg/kg soil dw
Assessment factor:
3
Extrapolation method:
sensitivity distribution

Hazard for predators

Additional information

See CSR Annex 4 - PNEC Summary Report

Conclusion on classification

In line with the risk assessment/classification approach adopted for other metals and inorganic metal compounds (ECHA, 2012), ecotoxicity data are reported in terms of the concentration of dissolved silver ions from soluble inorganic silver species. Predominantly, these are studies that used silver nitrate (AgNO3) as the source of dissolved silver ions. Silver nitrate is considered to be the form of silver with the greatest toxicity as it dissociates rapidly and completely in aqueous solution. Where data for silver nitrate was not available, data derived from other inorganic salts (e.g. silver chloride) were used but only after the exposure conditions were determined to be acceptable (e.g. testing was conducted within the limits of solubility and the Ag+was likely to be fully dissociated).

 

A complete base set of acute ecotoxicity studies is available for soluble inorganic silver species, comprising numerous studies for fish, invertebrates and algae. The lowest reliable acute value is an EC50 of 0.22 µg Ag/L for the invertebrate Daphnia magna (Bianchini et al., 2002). A complete chronic data set is also available for soluble inorganic silver species, with chronic ecotoxicity data available for various species of fish, invertebrates and algae. The lowest reliable chronic value is an EC10 of 0.16 µg Ag/L for the blue-green algae Nostoc muscorum (Rai et al. 1990). Additional chronic toxicity data of similar sensitivity are also available for the brown trout Salmo trutta (217 day EC10 of 0.19 µg Ag/L) and Oncorhynchus mykiss (196 day EC10 of 0.17 µg Ag/L) obtained from Davies et al. (1998).

 

For silver and silver compounds, the acute ecotoxicity reference value (ERV) is 0.22 µg Ag/L and the chronic ERV is 0.16 µg Ag/L.

The classification and labelling guidance states that if the solubility of a metal compound is greater than the L(E)C50 then it should be classified for acute and chronic hazard based on the available ecotoxicity data and the standard classification criteria. On 10th March 2011, Commission Regulation (EC) No 1272/2008 [CLP Regulations] was amended for the second time. The acute environmental classification is still based on acute data. However, the chronic environmental classification is now based on a chronic data set, if this is available. A complete chronic data set is available for silver and silver compounds.

Silver nitrate

Silver nitrate is classified in Annex I of Directive 67/548/EEC. The classification assigned to silver nitrate is R50/53: very toxic to aquatic organisms; may cause long term adverse effects in the aquatic environment. This has been harmonised to Acute Category 1, Chronic Category 1 under the CLP Regulations (CLP Regulation 1272/2008).

 

For silver and silver compounds, the acute ecotoxicity reference value (ERV) is 0.22 µg Ag/L and the chronic ERV is 0.16 µg Ag/L. The solubility of silver nitrate is >1000 g/L (GETIS database 2009).

The solubility of silver nitrate is greater than the ecotoxicity reference values and therefore, silver nitrate is treated as a ‘soluble substance’. As such, theclassification for acute and chronic hazard is based on the available ecotoxicity data and the standard classification criteria. As the acute ERV is <1 mg/L, silver nitrate meets the criteria for classification as acute category 1. As the chronic ERV is <0.1 mg/L, silver nitrate also meets the criteria for chronic category 1 classification. The available data confirm the classification of silver nitrate as listed on Annex I of the DSD and harmonised under the CLP Regulations.

Under the CLP Regulations, an acute M factor must also be assigned to substances classified as Acute Category 1 and/or Chronic Category 1. Treating silver nitrate as a soluble substance and on the basis of an acute ERV of 0.22 µg Ag/L and a chronic ERV of 0.16 µg Ag/L, the acute M factor is 1000 and the chronic M factor is 100.