Abstract
For dusty environments consideration is being given to estimating an exposure from formaldehyde leached from particulate matter once it enters the respiratory tract. Approaches developed for determination of formaldehyde which may be released from formaldehyde resin-containing dusts involve leaching in water at physiological temperature for 4 to 6 hours and measuring the leached formaldehyde by the 2, 4-dinitrophenylhydrazine (2, 4-DNPH), chromotropic acid (CTA), or acetylacetone (ACE) (Hantzsch Reaction) analysis procedures. A previous study of wood and paper product dusts showed that CTA indicated ten times higher levels of formaldehyde than those measured by ACE. A lack of information exists on releasable formaldehyde measured by 2, 4-DNPH versus ACE and CTA on similar samples. This study presents a comparison of the amounts of releasable formaldehyde measured by these three procedures applied to water extracts of formaldehyde resin-containing wood and paper product dusts and expands the number of matrices for which this methodology has been applied. Wood dusts prior to the addition of resin showed negligible releasable formaldehyde by all three procedures. Similar releasable formaldehyde levels were measured by 2, 4-DNPH and CTA for urea-formaldehyde and phenol-formaldehyde resin-containing wood and paper product dusts. These levels were consistently about ten times higher than those measured by ACE. The finding that 2, 4-DNPH and CTA gave similar results suggests that both methods measured bound (i.e., formaldehyde formed by the analysis procedure) as well as unbound formaldehyde in the aqueous extracts, whereas ACE measured predominantly unbound formaldehyde.