Disodium wolframate

Toxicity to birds

Link to relevant study record(s)

Reference

Endpoint:

toxicity to birds, other

Remarks:

Dietary toxicity test

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Insufficient information provided on materials methods and results to adequately evaluate the data. Lacking detail on husbandry, housing, dosing accuracy, and statistical analysis.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Hens were fed the test substance, and xanthine dehydrogenase levels were monitored in the tissues. Chicks from eggs laid by these birds were then used in growth tests where they were fed additional test substance or not. These chicks were compared to chicks whose hens had not been fed the test substance. Xanthine dehydrogenase levels were monitored in the tissues of the chicks as well.

GLP compliance:

no

Dose method:

feed

Analytical monitoring:

no

Vehicle:

not specified

Details on preparation and analysis of diet:

Breeder ration supplement with 250 ppm tungsten, as sodium tungstate.

Test organisms (species):

other: Breeder hens, (WPC)

Details on test organisms:

TEST ORGANISM
- Common name: Breeder hens
- Sexes used: Females, with adequate males to ensure maximum fertility

Limit test:

no

Total exposure duration (if not single dose):

4 wk

Remarks:

Hens fed tungsten for 30 days prior to setting and hatching eggs.

Post exposure observation period:

None

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

Experiment 1- Controls-65 hens, Treated-95 hens
Experiment 2, Trial 1- 40 chicks treated, (20 from treated hens, 20 from control); 40 chicks not treated (20 from treated hens, 20 from control)
Experiment 2, Trial 2- 52 chicks treated (26 from treated hens, 26 from control) 40 chicks not treated (26 from treated hens, 26 from control)

Control animals:

yes, plain diet

Nominal and measured doses / concentrations:

Experiment 1-Hens-First 10 days, 250 ppm test substance, the next 20 days, 500 ppm test substance.
Experiment 2, Trial 1 -Chicks, 500 ppm test substance, 4 weeks (breeder ration)
Experiment 2, Trial 2-Chicks, 500 ppm test substance, 24 days (broiler ration)

Details on test conditions:

-No information on adult hen conditions.
-Chicks were reared in starter-type battery brooders equipped with wire screen floors.
-Chicks were fed food and water ad libitum.
-Weekly chick weights and individual gain and feed conversion data were collected.

Details on examinations and observations:

N/A

Details on reproductive parameters:

N/A

Reference substance (positive control):

no

Duration (if not single dose):

30 d

Dose descriptor:

LOEC

Effect level:

500 mg/kg diet

Conc. / dose based on:

test mat.

Basis for effect:

other: decline in xanthine dehydrogenase activity

Remarks on result:

other: Experiment 1

Duration (if not single dose):

10 d

Dose descriptor:

NOEC

Effect level:

250 mg/kg diet

Conc. / dose based on:

test mat.

Basis for effect:

other: decline in xanthine dehydrogenase activity

Remarks on result:

other: Experiment 1

Duration (if not single dose):

30 d

Dose descriptor:

NOEC

Effect level:

500 mg/kg diet

Conc. / dose based on:

test mat.

Basis for effect:

other: egg production and hatchability

Remarks on result:

other: experiment 1

Duration (if not single dose):

4 wk

Dose descriptor:

LOEC

Effect level:

500 mg/kg diet

Conc. / dose based on:

test mat.

Basis for effect:

other: feed conversion and growth depression

Remarks on result:

other: Experiment 2; only one concentration tested

Mortality and sub-lethal effects:

No mortality was reported

Reported statistics and error estimates:

Analysis of variance was used to compare results within the same experiment.

Test Results:

Experiment 1

- The addition of 250 ppm sodium tungstate had little or no effect on the xanthine dehydrogenase activity of the hen tissues tested.

- 500 ppm tungsten caused a steady decline in xanthine dehydrogenase activity, which appeared to stabilize around 30 days.

- Neither level of sodium tungstate had an apparent effect on the rate of egg production or hatchability.

Experiment 2, Trial 1 and Trial 2

-Day old chicks from hens fed tungstate had significantly higher amounts of xanthine dehydrogenase in the liver and intestine than did chicks from hens receiving no tungstate.

- Chicks from hens fed the tungsten-supplemented ration grew at a significantly slower rate than did the control chicks on both the breeder ration and the broiler ration.

- When the chick ration was supplemented with 500 ppm tungsten, a slower rate of gain was observed when compared to rations containing no supplementation.

- At four weeks of age, there appeared to be no difference in the xanthine dehydrogenase activities between the chicks, regardless of the ration fed or the hen treatment

-The variation that occurred in the enzyme determinations was large, and the sample size relatively small. This may have accounted for there being no statistical differences.

Conclusions:

Chicks from hens fed a sodium tungstate supplemented ration grew at a significantly slower rate than controls. Chicks fed sodium tungstate grew at a slower rate than chicks who were not fed the test substance. 500 ppm test substance did not appear to effect egg production or hatchability.

Description of key information

Several older studies on chicken species were identified in which the birds were fed varying amounts of tungsten, in the form of sodium tungstate in their diets.  The NOAELs identified from these studies ranged from approximately 45-500 mg tungsten/kg, depending on which endpoints were examined in each study.  However, none of these studies were conducted with standard methodology and they were deemed to be less than reliable

Key value for chemical safety assessment

Short-term EC50 or LC50 for birds:

45 mg/kg food