Calcium magnesium oxide

Health surveillance data

Administrative data

Endpoint:

health surveillance data

Type of information:

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

Adequacy of study:

supporting study

Study period:

no data available

Reliability:

other: high

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well-documented study on the prevalence of chronic respiratory symptoms and ventilatory function among cement workers. However, no dust concentrations were measured. Local effects in the respiratory tract following inhalation of lime dust are attributed to the alkaline reaction of lime in contact with water (in this case the humidity of mucous membranes). Addition of water to cement or Portland cement can raise the pH to values exceed 13, thus giving a more alkaline mixture than that from CaO and Ca(OH)2. Since pH change is the primary adverse effect leading to irritation of the mucosa and impaired ventilatory function, (Portland) cement can be used as a surrogate to predict effects and safe exposure levels for lime. The following additional information should be considered: (Portland) cement contains hexavalent chromium which is, however, not contained in lime at significant concentrations. Until the addition of ferrous sulphate became a common procedure, cement contained about 5-10 mg Cr(VI)/kg of cement; a content of 20 mg Cr(VI)/kg has also been reported . After the addition of ferrous sulphate, the level of Cr(VI) decreased to less than 2 mg/kg. This reasoning was also used by the Scientific Committee on Occupational Exposure Limits (SCOEL) in their recommendation occupational exposure limits for calcium oxide (CaO) and calcium hydroxide (Ca(OH)2) (see 7.5.3, Repeated dose toxicity: inhalation). The current paper was considered by SCOEL for establishing the STEL and the 8 h TWA OEL for lime, employing read-across from (Portland) cement to lime.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Respiratory illnesses and ventilatory function among workers at a cement factory in a rapidly developing country

Author:

Al-Neaimi, Y.I.; et al.

Year:

2001

Bibliographic source:

Occup. Med. 51, 367-373

Materials and methods

Study type:

health record from industry

Endpoint addressed:

repeated dose toxicity: inhalation

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Cross-sectional study on respiratory system effects of Portland cement workers.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

cement dust

IUPAC Name:

cement dust

Details on test material:

- Name of test material (as cited in study report): Cement dust
No further details are given.

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

The cohort for analysis consisted of 67 male workers from a cement factory in United Arab Emirates and 134 subjects without any exposure to dust, fumes or gases. The mean age was 44.4 ± 7.55 and 44.23 ± 9.93 years for the exposed and unexposed subjects, respectively. The mean years of work in the current job were 11.4 ± 5.2 and 13.5 ± 3.8 years, respectively.
Information on socio-demographic characteristics, smoking profile, respiratory history, a general health profile and a current health status was collected through an interviewer-administered questionnaire. In the ventilatory function test, three reproducible tracings were obtained. The vital capacity (VC), forced vital capacity (FCV), forced expiratory volume in 1 sec (FEV1), peak expiratory flow (PEF), and ratios of forced expiratory volume to vial capacity (FEV1/VC) and forced expiratory volume to vital capacity (FEV1/FVC) were measured.

Results and discussion

Results:

A higher percentage of the exposed workers reported recurrent and prolonged cough, phlegm, wheezing, dyspnoea, bronchitis, sinusitis, shortness of breath and bronchial asthma compared with the respective percentage of the non-exposed group.
Ventilatory function (VC, FCV, FEV1, FEV1/VC, FEV1/FVC and PEF) was significantly lower in the exposed workers compared with non-exposed group. These differences could not be explained by age, body mass index or packed-years smoked.
Ventilatory function, as measured by FEV1/FVC, showed that 36 % of the exposed workers had some impairment compared with 10 % of those unexposed.
The mean differences in the pulmonary function values among the exposed smokers and non-smokers and among the non-exposed smokers and non-smokers were not statistically significant in terms of 95% confidence intervals. However, among the smokers, the exposed workers had significantly lower values for FEV1, FEV1/VC, FEV1/FVC and PEF compared with the unexposed smokers.

Applicant's summary and conclusion

Conclusions:

The data suggest that occupational exposure to cement dust may lead to higher prevalence of chronic respiratory symptoms and impairment of ventilatory function.
However, due to lack of information on exposure levels, the usefulness of this study is limited.