Hydrogen fluoride

Toxicity to birds

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

other: published review

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published WHO review of available data

Qualifier:

no guideline followed

Principles of method if other than guideline:

The article reviews the toxicity data for birds.

GLP compliance:

not specified

Remarks:

: review document

Specific details on test material used for the study:

Although sodium fluoride has been identified as the test material for the current study summary, it should be noted that the publication (WHO, 2002) reports avian toxicity data for various fluoride species, not just sodium fluoride.

Dose method:

feed

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

other: Sturnus vulgaris; Otus asio; Falco sparverius

Limit test:

no

Remarks:

various exposure durations

No. of animals per sex per dose and/or stage:

No information available in review

Control animals:

yes, plain diet

Duration (if not single dose):

24 h

Dose descriptor:

LD50

Effect level:

50 other: mg F-/kg bw

Basis for effect:

mortality

Remarks on result:

other: 1 day old European Starling Chicks

Remarks:

(Fleming et al., 1987)

Duration (if not single dose):

24 h

Dose descriptor:

LD50

Effect level:

17 other: mg F-/kg bw

Basis for effect:

mortality

Remarks on result:

other: 16 day old European Starling nestlings

Remarks:

(Fleming et al., 1987)

Dose descriptor:

NOEC

Effect level:

10 other: mg NaF/kg diet

Basis for effect:

reproductive parameters

Remarks on result:

other: Kestrels, no adverse effects were noted at this dose but it was associated with a higher fertility

Remarks:

(Bird and Massari, 1983)

Dose descriptor:

NOEC

Effect level:

18 other: mg F-/kg diet

Basis for effect:

reproductive parameters

Remarks on result:

other: Eastern-Screech Owls

Remarks:

(Hoffman et al., 1985; Pattee, et al., 1988)

Repellency factors (if applicable):

Not applicable.

In birds, the 24-h LD₅₀ was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Growth rates were significantly reduced at 13 and 17 mg fluoride/kg body weight (the highest doses at which growth was monitored) (Fleming et al., 1987).

Kestrels were fed a diet to which flour contaminated with fluoride (10, 50 or 500 ppm) had been applied. The birds receiving the highest fluoride dose died within 6 days. Fluoride at the lower doses had no effect on clutch size, hatchability or fledging success but was associated with a higher fertility. Eggs laid by kestrels at 50 mg/kg had significantly thicker shells (Bird and Massari, 1983).

Lower reproductive success of eastern screech-owls (Otus asio) was noted when birds were fed 200 ppm fluoride in the diet, but not when fed 40 ppm fluoride in the diet. Fluoride at 40 ppm resulted in significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were present. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter (Hoffman et al., 1985; Pattee, et al., 1988).

Validity criteria fulfilled:

not applicable

Conclusions:

In birds, the 24-h LD50 was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Fluoride fed in the diet can affect the reproductive performance of birds.

Executive summary:

In birds, the 24-h LD₅₀ was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Growth rates were significantly reduced at 13 and 17 mg fluoride/kg body weight (the highest doses at which growth was monitored) (Fleminget al., 1987).

Kestrels were fed a diet to which flour contaminated with fluoride (10, 50 or 500 mg/kg) had been applied. The birds receiving the highest fluoride dose died within 6 days. Fluoride at the lower doses had no effect on clutch size, hatchability or fledging success but was associated with a higher fertility. Eggs laid by kestrels at 50 mg/kg had significantly thicker shells (Bird and Massari, 1983).

Lower reproductive success of eastern screech-owls (Otus asio) was noted when birds were fed 90 mg fluoride/kg diet wet weight (as sodium fluoride), but not when fed 18 mg fluoride/kg diet (Hoffman et al., 1985; Pattee,et al., 1988).

Reference 2

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

It is considered appropriate to address the toxicity to terrestrial arthropods data requirement for hydrogen fluoride (HF) by read-across to available data on sodium fluoride (NaF).

In water, HF dissociates rapidly to form hydrogen (H+) and fluoride (F−) ions, whereas NaF rapidly dissociate to sodium (Na+) and F- ions. Since all biological systems are water based, both HF and NaF will dissociate rapidly to form F− ions in contact with cells, mucous, blood or other fluids. Any effects observed will be directly attributable to the F− ion. The Na+ ion is naturally occurring and regulated by organisms (i.e. by homeostatic mechanisms) and consequently is not considered to have an impact on the read-across of ecotoxicological data. On this basis, the profile of HF is comparable to that of NaF with respect to the environment.

Reason / purpose for cross-reference:

read-across source

Duration (if not single dose):

24 h

Dose descriptor:

LD50

Effect level:

50 other: mg F-/kg bw

Basis for effect:

mortality

Remarks on result:

other: 1 day old European Starling Chicks

Remarks:

(Fleming et al., 1987)

Duration (if not single dose):

24 h

Dose descriptor:

LD50

Effect level:

17 other: mg F-/kg bw

Basis for effect:

mortality

Remarks on result:

other: 16 day old European Starling nestlings

Remarks:

(Fleming et al., 1987)

Dose descriptor:

NOEC

Effect level:

10 other: mg NaF/kg diet

Basis for effect:

reproductive parameters

Remarks on result:

other: Kestrels, no adverse effects were noted at this dose but it was associated with a higher fertility

Remarks:

(Bird and Massari, 1983)

Dose descriptor:

NOEC

Effect level:

18 other: mg F-/kg diet

Basis for effect:

reproductive parameters

Remarks on result:

other: Eastern-Screech Owls

Remarks:

(Hoffman et al., 1985; Pattee, et al., 1988)

Repellency factors (if applicable):

Not applicable.

In birds, the 24-h LD₅₀ was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Growth rates were significantly reduced at 13 and 17 mg fluoride/kg body weight (the highest doses at which growth was monitored) (Fleming et al., 1987).

Kestrels were fed a diet to which flour contaminated with fluoride (10, 50 or 500 ppm) had been applied. The birds receiving the highest fluoride dose died within 6 days. Fluoride at the lower doses had no effect on clutch size, hatchability or fledging success but was associated with a higher fertility. Eggs laid by kestrels at 50 mg/kg had significantly thicker shells (Bird and Massari, 1983).

Lower reproductive success of eastern screech-owls (Otus asio) was noted when birds were fed 200 ppm fluoride in the diet, but not when fed 40 ppm fluoride in the diet. Fluoride at 40 ppm resulted in significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were present. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter (Hoffman et al., 1985; Pattee, et al., 1988).

Validity criteria fulfilled:

not applicable

Conclusions:

In birds, the 24-h LD50 was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Fluoride fed in the diet can affect the reproductive performance of birds.

Executive summary:

It is considered appropriate to address the toxicity to terrestrial arthropods data requirement for hydrogen fluoride (HF) by read-across to available data on sodium fluoride (NaF). In water, HF dissociates rapidly to form hydrogen (H⁺) and fluoride (F⁻) ions, whereas NaF rapidly dissociate to sodium (Na⁺) and F^- ions.Since all biological systems are water based, both HF and NaF willdissociate rapidly to form F⁻ ions in contact with cells, mucous, blood or other fluids.Any effects observed will be directly attributable to the F⁻ ion. The Na⁺ ion is naturally occurring and regulated by organisms (i.e. by homeostatic mechanisms) and consequently is not considered to have an impact on the read-across of ecotoxicological data. On this basis, the profile of HF is comparable to that of NaF with respect to the environment.

In birds, the 24-h LD₅₀ was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Growth rates were significantly reduced at 13 and 17 mg fluoride/kg body weight (the highest doses at which growth was monitored) (Fleminget al., 1987).

Kestrels were fed a diet to which flour contaminated with fluoride (10, 50 or 500 mg/kg) had been applied. The birds receiving the highest fluoride dose died within 6 days. Fluoride at the lower doses had no effect on clutch size, hatchability or fledging success but was associated with a higher fertility. Eggs laid by kestrels at 50 mg/kg had significantly thicker shells (Bird and Massari, 1983).

Lower reproductive success of eastern screech-owls (Otus asio) was noted when birds were fed 90 mg fluoride/kg diet wet weight (as sodium fluoride), but not when fed 18 mg fluoride/kg diet (Hoffman et al., 1985; Pattee,et al., 1988).

Description of key information

Various studies are summarised in the WHO (2002) review. 24-h LD50 values were 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings.

Additional information

The World Health Organisation reviewed several studies that investigated fluoride toxicity in birds.

In birds, the 24-h LD₅₀ was 50 mg/kg body weight for 1-day-old European starling (Sturnus vulgaris) chicks and 17 mg/kg body weight for 16-day-old nestlings. Growth rates were significantly reduced at 13 and 17 mg fluoride/kg body weight (the highest doses at which growth was monitored).

Kestrels were fed a diet to which flour contaminated with fluoride (10, 50 or 500 mg/kg) had been applied. The birds receiving the highest fluoride dose died within 6 days. Fluoride at the lower doses had no effect on clutch size, hatchability or fledging success but was associated with a higher fertility. Eggs laid by kestrels at 50 mg/kg had significantly thicker shells. Lower reproductive success of eastern screech-owls (Otus asio) was noted when birds were fed 90 mg fluoride/kg diet wet weight (as sodium fluoride), but not when fed 18 mg fluoride/kg diet