Hexafluorosilicic acid

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Workers were exposed to a variety of compounds, including hexafluorosilicic acid, hydrogen fluoride and silicon tetraluoride. Paper summarised in NTP review (seondary source).

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Risk of fluorosis in the manufacture of phosphate fertilizers

Author:

Fabbri L , De Rosa E, Potenza I, Mapp C, Rossi A, Brighenti F & Forin F

Bibliographic source:

La Medicina del lavoro 69(5) 594-604

Reference 2

Reference Type:

secondary source

Title:

Sodium Hexafluorosilicate [CASRN 16893-85-9] and Fluorosilicic Acid [CASRN 16961-83-4] Review of Toxicological Literature

Author:

Haneke KE & Carson BL

Year:

2001

Bibliographic source:

National Institute of Environmental Health Sciences P.O. Box 12233 Research Triangle Park, North Carolina 27709 Contract No. N01-ES-65402

Materials and methods

Study type:

cohort study (retrospective)

Endpoint addressed:

repeated dose toxicity: inhalation

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Epidemiological study investigating the risk of fluorosis in workers involved in the manufacture of phosphate fertiliser.

GLP compliance:

no

Remarks:

: not applicable

Test material

Test material information

Constituent 1

Reference substance name:

Hexafluorosilicic acid

EC Number:

241-034-8

EC Name:

Hexafluorosilicic acid

Cas Number:

16961-83-4

Molecular formula:

F6Si.2H

IUPAC Name:

Dihydrogen hexafluorosilicate

Details on test material:

Workers were exposed to gaseous fluoride (hydrogen fluoride, silicon tetrafluoride, and hexafluorosilicic acid).

Method

Details on study design:

50 workers were engaged for approximately 30 years in the production of phosphate fertilisers.

Exposure assessment:

not specified

Results and discussion

Results:

Nine of 50 workers had increased bone densities. Urinary fluoride excretion ranged from 1.0 to 9.6 mg/L

Confounding factors:

Workers were co-exposed to gaseous fluoride (hydrogen fluoride, silicon tetrafluoride, and hexafluorosilicic acid), therefore no effects can be attributed to hexafluorosilicic acid.

Strengths and weaknesses:

Workers were co-exposed to gaseous fluoride (hydrogen fluoride, silicon tetrafluoride, and hexafluorosilicic acid), therefore no effects can be attributed to hexafluorosilicic acid.

Any other information on results incl. tables

Increased bone density and increased urinary excretion of fluoride were reported, however workers were also exposed to hydrogen fluoride and silicon tetrafluoride in addition ro hexafluorosilicic acid. No conclusion can therefore be reached regarding the contribution of hexafluorosilicic acid.

Applicant's summary and conclusion

Conclusions:

Increased bone density and increased urinary excretion of fluoride were reported, however workers were also exposed to hydrogen fluoride and silicon tetrafluoride in addition to hexafluorosilicic acid. No conclusion can therefore be reached regarding the contribution of hexafluorosilicic acid.

Executive summary:

The risk of fluorosis in workers involved in the manufacture of phosphate fertiliser was investigated in 50 workers engaged for approximately 30 years. Urine levels of fluoride were measured and bone density assessed. Increased bone density and increased urinary excretion of fluoride were reported, however workers were also exposed to hydrogen fluoride and silicon tetrafluoride in addition ro hexafluorosilicic acid. No conclusion can therefore be reached regarding the contribution of hexafluorosilicic acid.