This study found a statistically significant excess risk of bladder cancer, with a duration-response trend, among male primary metal workers and automechanics, and female office workers engaged in general clerical duties.
To clarify the inconsistent reports of bladder cancer risk in foundry workers, a meta-analytic review of epidemiological studies was undertaken. Summary risk estimates (SRE) were calculated from 40 systematically extracted results. Weakly increased risks were observed overall, with an SRE of 1.11. Twenty three selected study results with better exposure information yielded an SRE of 1.16. This weak increase in risk is consistent with estimates obtained from dose-response trends of PAH exposures in aluminium smelter workers. Summary estimates did not vary substantially with exposure quality, study design, control for smoking, or when limiting the meta-analysis to large study results. Exposure-response findings showed significantly increased risks of about 1.6 to 1.7 after 20 or more years of employment, but this was based on few studies. Occupation specific SREs showed a 40–50% increased risk among moulders, casters, and unskilled foundry labourers. There was limited evidence that bladder cancer risk correlated with lung cancer risk, which is a more established risk among foundry workers. The small increased risk observed is prone to bias and confounding. Further studies of dose-response trends would greatly aid in determining whether this observed association is causal.
Procedures for monitoring formaldehyde concentration in air ultimately require a standard solution with which to calibrate the response of the analytical method. Although formaldehyde solutions of nominal concentration may be prepared from a variety of sources, the solutions must be standardized. The sulfite-pW titration method was tested and found to give erratic results. This paper presents evidence to indicate that the sulfite-pHhitration procedure requires modification. This modified procedure was used to standardize solutions of free formaldehyde. One of these standardized solutions was used to calibrate the chromotropic acid colorimetric procedure for formaldehyde. The calibrated colorimetric method accurately quantitated the concentration of a solution prepared from dry sodium formaldehyde bisulfite, previously calibrated using the direct-iodinekitration method. This correlation indicates that the modified sulfite-pHhitration standardization procedure is an accurate means of standardizing formaldehyde solutions. An independent oxidatiordformate ion chromatography analysis method was devised to confirm the accuracy of the modified sulfite-pHhitration method. Gaertner, R.R.W.: Modification of a pH-Titration Standardization Method for Formaldehyde. Appl.
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