Past Occupational Exposure to Airborne Manganese in a Manganese Alloy Plant
Bibliographic record
Abstract
A retrospective exposure assessment of a group of manganese (Mn) alloy workers was performed in conjunction with a 2004 follow-up study, 14 years after cessation of exposure, to evaluate the long-term effects of occupational Mn exposure on neurobehavioral functions. The ferro- and silico-Mn alloy plant opened in 1973 and closed in 1991. The airborne total Mn (TMn) exposures for job groupings were established using personal sampling data from a 1991 industrial hygiene survey. Historical short-term total dust (TDust) data were used to estimate past TDust exposure for job groupings and plant areas. Relationships between Mn content and TDust from the 1991 survey, supported by sparse historical data, were used to estimate TMn content in the historical TDust data. Results showed past personal TDust exposure levels much higher than those found in 1991. Changes in TDust levels and corresponding TMn levels were a function of changes in ventilation, work practices, and operations, not of product (ferro- or silico-Mn). Relationships between TMn and respirable Mn (RMn) from area sampling in 1991 were used to estimate RMn exposure for the job groups. Work histories for 112 workers were developed from payroll records, questionnaires, and interviews and combined with Mn exposure estimates to develop cumulative exposure indices (CEIs). The TMn CEI ranged from 0.27 mg/m(3)x years to 100.24 mg/m(3)x years, with an AM of 24.40 mg/m(3)x years and a GM of 14.06 mg/m(3)x years. The RMn CEI had an AM of 2.95 mg/m(3)x years and a GM of 1.78 mg/m(3)x years with a range of 0.05-12.03 mg/m(3)x years. Overall average TMn exposure intensity, the TMn CEI divided by time worked in years for each worker, had an AM of 1.6 mg Mn/m(3), a GM of 1.0 mg Mn/m(3), range 0.02-6.2 6 mg Mn/m(3). The results of the 2004 follow-up study showed several concentration-response relationships between TMn CEI and neurobehavioral outcomes, which suggest that increase in cumulative TMn exposure level has long-term consequences on the nervous system.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".