2,2'-bipyridyl

Endpoint summary

Description of key information

Two studies for acute oral toxicity are available.
Groce 1982: LD50 values (rat, oral) of 100 and 107 mg/kg bw for male and female rats were reported.
Williamson 1972: LD50 (rat, oral) between 250 and 500 mg/kg bw.

Four studies for acute dermal toxicity are available.
Williamson (1972): LD50 (rat, dermal) between 625 and 1250 mg/kg bw.
Allen (1987a): The LD50 (rat dermal) of the test item was found to be between 0.25 and 0.6 mL/kg bw. A conversion into mg/kg bw was not possible due to missing information on density of the test item.
Allen (1987b): The LD50 (rat dermal) of the test item was found to be between 400 and 1000 mg/kg bw.
Allen (1987c): The LD50 (rat dermal) of the test item was >400 mg/kg bw.

No data are available on inhalation toxicity of 2,2’-bipyridine.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

100 mg/kg bw

Quality of whole database:

lowest LD50 value reported

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

discriminating dose

Value:

625 mg/kg bw

Additional information

Both acute oral toxicity studies are lacking documentation. Although the study of Groce (1982) is described quite well, the information on the actually administered doses is not very clear. Information on housing or treatment of the animals are lacking in both studies.

Single oral application of 2,2’-bipyridine caused the same clinical signs in both studies such as tremors, orange-to-red coloured urine, and subdued behaviour. Animals died usually 1 to 2 days after administration of the test item.

Based on the data from the studies it can be concluded that the acute oral LD50 (rat) for 2,2’-bipyridine is in the range 100 -500 mg/kg bw.

 

All four acute dermal toxicity studies lack documentation, especially information on substance identification and purity. In fact, in neither of the studies of Allen, substance sameness to 2,2’-bipyridine cannot be emanated from the test item description, which only states the names “crude biphenyl”, “treated crude biphenyl”, and “biphenyl reactor stream”.

Nevertheless, in all four available studies, the LD50 (dermal) was found to be in a similar range: Williamson (1972)reports a LD50(rat, dermal) between 625-1250 mg/kg bw whereas the studies of Allen (1987) (a, b and c) give LD50 values (rat, dermal) of >0.25 and <0.6 mL/kg bw, 400 - 1000 mg/kg bw and of >400 mg/kg bw, respectively.

Using a conservative weight of evidence approach, the key value for chemical safety assessment was therefore said to be in a range of 625 - 1000 mg/kg bw.

Justification for classification or non-classification

Data from the two acute oral toxicity studies indicate that the acute oral LD50 (rat) for 2,2’-bipyridine is in the range 100 -500 mg/kg bw. Based upon the classification criteria according to the Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008, the test item 2,2’-bipyridine is classified into acute toxicity category III after oral application.

Data from the four acute dermal toxicity studies show that the acute dermal LD50 (rat) is between 625 and 1000 mg/kg bw 2,2’-bipyridine. Based upon the classification criteria according to the Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008, the test item 2,2’-bipyridine is classified into acute toxicity category III after dermal application.