Lower chlorinated PCBs accumulate in demolition workers while working on a contaminated worksite
Bibliographic record
Abstract
• Two-year biomonitoring study with demolition workers at a PCB-contaminated site. • 209 congeners in serum were compared to general demolition and office workers. • Demolition workers on PCB-site had elevated lower chlorinated PCBs after 1 year. • Age was a significant predictor of increases in serum PCBs. Several buildings in a Danish social housing estate exceeded indoor air guidance values for polychlorinated biphenyls (PCBs), leading to their demolition. Here, we conducted a biomonitoring study among the workers on-site (n = 24) to evaluate their exposure to all 209 PCBs across the two-year demolition. We compared their PCB serum concentrations and accumulation to those of demolition workers at other worksites (n = 21) and office workers (n = 17). Demolition workers were provided with personal protective equipment according to risk assessments for PCB-related work. Serum PCBs were measured from baseline and up to two annual follow-up visits using gas chromatography high-resolution mass spectrometry. Forty-six peaks representing 58 PCBs were detected in > 60 % of serum samples; eight congeners were found in every sample. PCB-153 was the most abundant congener (median = 22.1 ng/g lipid). After adjusting for age and smoking status, demolition workers after one year on the contaminated site experienced more than a four-fold increase in all lower chlorinated PCBs compared to office workers at baseline, with increases most prominent for tri- and tetra-CBs (10 β = 6.2 and 9.2, p < 0.01). Nine PCBs were significantly elevated from baseline to year 1 in only contaminated-site demolition workers, with the largest increase observed for PCB-66/80. For higher chlorinated PCBs, levels remained consistent or decreased slightly over the three samples from these workers. Those who worked in active demolition for at least 4 years at baseline experienced a 40 % increase (95 % CI: 10 %, 90 %) in the WHO-12 PCB sum. Age significantly predicted increases in PCBs, which tracked closely with logK ow values. Our study showed that despite safety measures, demolition workers who worked on a PCB-contaminated site experienced increased and accumulating internal exposure to lower chlorinated PCBs compared to general demolition and office workers. Consequently, workers’ safety should be carefully considered to reduce exposures among this high risk group.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 source (direct Gemma or distilled Codex), 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".