| Document ID (ISN) | 101980 |
| CIS number |
03-787 |
| ISSN - Serial title |
0003-4878 - Annals of Occupational Hygiene |
| Year |
2001 |
| Convention or series no. |
|
| Author(s) |
Symanski E., Sällsten G., Chan W., Barregård L. |
| Title |
Heterogeneity in sources of exposure variability among groups of workers exposed to inorganic mercury |
| Bibliographic information |
Nov. 2001, Vol.45, No.8, p.677-687. 37 ref. |
| Abstract |
Given the utility of different modelling approaches when assessing exposures, assumptions of homogeneity of variance within and between workers using both random- and mixed-effects models were investigated. In this study of four groups of workers exposed to inorganic mercury (Hg) at a chloralkali plant, there was no evidence of significant heterogeneity in the levels of variation over time or between workers for air Hg levels. For the biological monitoring data, however, the findings indicate that groups did not share common levels of variability and that it was not appropriate to pool the data and obtain single estimates of the within- and between-worker variance components. Classification of job group as a random or fixed effect had no effect on the results. Although the probability that workers' mean exposures exceeded occupational exposure limits for air, urine and blood Hg was generally low (<10%) for all groups except maintenance workers, the estimated values sometimes varied depending upon the particular model that was applied. Given the growing use of random- and mixed-effects models that combine data across occupational groups, additional studies are warranted to evaluate whether it is reasonable to assume common variances and covariances among measurements collected on workers from different groups. |
| Descriptors (primary) |
chemical industry; exposure tests; mathematical models; mercury |
| Descriptors (secondary) |
probability analysis; inorganic chemicals; description of technique; collective variables; statistical evaluation; exposure evaluation |
| Document type |
D - Periodical articles |
| Country / State or Province | Sweden; USA |
| Subject(s) |
Chemicals, plastics and rubber
|
| Broad subject area(s) |
Chemical safety
|
| Browse category(ies) |
Inorganic substances
Biological monitoring
Chemical industry
Mercury and compounds
|
