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Ecotoxicological information

Toxicity to birds

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Description of key information

NOEC (90 d) = 630 mg Trinickel Dicitrate/kg diet

Key value for chemical safety assessment

Additional information

Six sub-chronic and chronic feeding studies in which the diet was spiked with a Ni salt were identified in the EU-RAR (2008, seeTable 3.2.4-2 in the attached document of the key endpoint study record of chapter 6.3.5). The most sensitive lowest observed effect concentration (LOEC) from these six studies, focusing on endpoints related to survival, growth, and reproduction, was 300 mg/kg (as added Ni) based on a 21-day study with White Plymouth Rock day-old male chicks. This LOEC is based on a 14% reduction in body weight relative to the control chicks. A NOEC of 150 mg/kg was estimated by Waegeneers and Smolders (2003) by dividing the LOEC by 2 as per TGD guidance.

In a further study Cain and Pafford (1981) observed tremors in all ducklings fed a dietary Ni concentration of 800 mg/kg or greater. Although all but two ducklings in the 800 mg/kg dietary treatment survived throughout the 90-day exposure period, all ducklings continued to tremor throughout the experimental period of 90 days. At a dietary Ni concentration of 200 mg/kg, all ducklings survived and none developed tremors. So the study of Cain and Pafford (1981) resulted in a NOEC of 200 mg Ni/kg. More confidence is placed in the NOEC of Cain and Pafford (1981) than that of Ling and Leach (1979) because the former was a measured NOEC from a longer study. Nevertheless, both the mallard and chicken NOECs of 200 and 150 mg Ni/kg (according to 630 and 472 mg Trinickel Dicitrate/kg), respectively, are used to derive the PNECs in the first tier of the risk characterization given in the EU-RAR.

Further tiered approach was developed and applied for the terrestrial food chain. The default approach suggested by the European Union’s Technical Guidance Document was always used as the first tier. If potential risk was concluded from this tier, then in subsequent assessment tiers, refinements on absorption of dietary nickel and the dietary composition of the predators were considered.