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Ecotoxicological information

Toxicity to birds

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Description of key information

An OECD Guideline 205 (Avian Dietary Toxicity Test) was the key study for determining short-term (5-day) toxicity of sodium cyanide in dietary water to mallard ducks (Platyrhynchos). The LC50, NOEC and No Mortality Concentration were determined.

Key value for chemical safety assessment

Additional information

The LC50 was determined to be 340 mg NaCN/l drinking water.

The NOEC was determined to be < 100 mg NaCN/l drinking water.

The No Mortality Concentration was determined to be 178 mg NaCN/l drinking water.

A PNEC was not derived on the basis of these values. The PNECaquatic(freshwater) is based upon long-term toxicity of cyanides to fish, invertebrates and algae. The PNECsoil for terrestrial organisms was based upon the uptake of cyanides from roots in water, which is the more sensitive endpoint. A PNECoral was not derived, since secondary poisoning is not of concern.

Potassium cyanide and sodium cyanide can be considered as a chemical category, along with hydrogen cyanide (HCN) and acetone cyanohydrin (ACH, also known as 2-hydroxy-2-methylpropanenitrile), based on structural similarity, similar physico-chemical properties and common breakdown/metabolic products in physical and biological systems. Particular attention is paid to the dissociation constant of HCN. In the vast majority of environmental and physiologic conditions, the cyanide salts will dissolve in water to form hydrogen cyanide. The physico-chemical hazards and toxicity result from the activity of this common proximal toxicant, HCN.An ECETOC Task Force, in the 2007 ECETOC Joint Assessment of Commodity Chemicals ( JACC ) Report No. 53, “Cyanides of Hydrogen, Sodium and Potassium, and Acetone Cyanohydrin (CAS No. 74-90-8, 143-33-9, 151-50-8 and 75-86-5)” supports the development of this chemical category. Hydrogen cyanide (Index No.006-006-00-X) and salts of hydrogen cyanide (Index No.006-007-00-5) are both listed in Annex VI,Table 3.1 of Regulation (EC) No. 1272/2008, entry 006-007-00-5, and are restricted in comparable ways taking into account physical characteristics. Thus, the assignment of potassium cyanide and sodium cyanide to a chemical category does not result in a less protective regulatory status.