Sodium metaphosphate

Endpoint summary

Description of key information

Supporting study:

No adverse effects were noted at male and female rats given the low and median doses (0.05 and 0.5%) of Sodium Hexametaphosphate (2 years study).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

abstract

Justification for type of information:

A scientific review.

Principles of method if other than guideline:

No information on the method. Male and female weanling rats (50 per group) were fed basal diet plus 0.05%, 0.5%, or 5.0% Sodium Hexametaphosphate.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Sex:

male/female

Route of administration:

oral: feed

No. of animals per sex per dose:

50

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Rats fed 0.5% to 5.0% Sodium Hexametaphosphate had increased kidney to body weight ratios. Renal infections were observed more frequently in rats of groups given Sodium Hexametaphosphate than in rats of the control group. Female rats of the high-dose group had “possibly increased” lung weights and decreased splenic weights. The incidence of renal infection made diffcult the interpretation of organ weights.
One female rat fed 0.5% Sodium Hexametaphosphate, and 13 of 20 rats given 5.0% Sodium Hexametaphosphate had calcination of the renal tubules.

Mortality:

mortality observed, treatment-related

Description (incidence):

A dose-related increase in mortality was not observed during the test period; however, overall mortality was 64% to 78% (females surviving better than males). The median life span was greatest in males given the medium dose of Sodium Hexametaphosphate. The most common cause of death was respiratory infection.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Rats of the control group had no observed effects on growth. Of rats given the low and median doses of Sodium Hexametaphosphate, no adverse effect swere noted.
Males of the high-dose group had reduced growth, but females of the same group were only slightly affected. Rats of the high-dose group had greater feed consumption at days 90 and 210, as compared to rats of the control group.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Description (incidence and severity):

Hematologic parameters did not differ from those of controls.

Clinical biochemistry findings:

not specified

Urinalysis findings:

no effects observed

Description (incidence and severity):

Only traces of protein and reducing substances were found in the urine.

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Rats fed 0.5% to 5.0% Sodium Hexametaphosphate had increased kidney to body weight ratios. Renal infections were observed more frequently in rats of groups given Sodium Hexametaphosphate than in rats of the control group. Female rats of the high-dose group had “possibly increased” lung weights and decreased splenic weights. The incidence of renal infection made diffcult the interpretation of organ weights.

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

effects observed, treatment-related

Description (incidence and severity):

The femur lengths were not significantly affected by treatment with Sodium Hexametaphosphate. The femurs of all rats had comparable water, ash, calcium, and phosphorus contents, and appeared normal in radiograph.

Conclusions:

No adverse effects were noted at male and female rats given the low and median doses (0.05 and 0.5%) of Sodium Hexametaphosphate (2 years study).

Executive summary:

No adverse effects were noted at male and female rats given the low and median doses (0.05 and 0.5%) of Sodium Hexametaphosphate (2 years study).

A dose-related increase in mortality was not observed during the test period; however, overall mortality was 64% to 78% (females surviving better than males). The median life span was greatest in males given the medium dose of Sodium Hexametaphosphate.