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PubMedDate not supplied

Release of formaldehyde and melamine from tableware made of melamine-formaldehyde resin.

The relationship between the concentrations of formaldehyde and melamine released into 4% acetic acid from dishes and bowls made of melamine-formaldehyde resin was determined. The average concentrations in the migration solution after the sample had been treated at 60, 80, and 95 degrees C for 30 min with 4% acetic acid were 0.0 +/- 0.1, 0.5 +/- 0.4 and 3.0 +/- 2.2 ppm, respectively for formaldehyde and 0.04 +/- 0.07, 0.21 +/- 0.20 and 1.19 +/- 1.18 ppm, respectively for melamine. The correlation between the concentrations of formaldehyde and melamine released at 95 degrees C was y=0.4858x-0.2728 (r=0.8860), where y is melamine concentration (ppm), x is formaldehyde concentration (ppm) and r is the correlation coefficient. The molar concentration ratios of formaldehyde to melamine (F/M ratio) were 15.4 +/- 11.6 at 80 degrees C and 14.9 +/- 10.1 at 95 degrees C. Hence the release of both migrants was affected by temperature but the F/M ratio was not affected. The release of both compounds was was increased on repetition of the migration test at 95 degrees C but their concentrations remained constant after the tenth and seventeenth repetitions of the treatment. During this period, the F/M ratio decreased according to the equation 1n y=-1.4344 1n x+3.7814 (r=-0.9984) for a sample before the tenth repetition of the treatment and remained between 1.7 and 1.9 after the twelfth repetition, where y is the F/M ratio and x is the number of repetitions of the treatment.

Acetates↗
PubMed1989

The sodium cycle in methanogenesis. CO2 reduction to the formaldehyde level in methanogenic bacteria is driven by a primary electrochemical potential of Na+ generated by formaldehyde reduction to CH4.

CH4 formation from CO2 and H2 rather than from formaldehyde and H2 in methanogenic bacteria is inhibited by uncouplers, indicating that CO2 reduction to the formaldehyde level is energy-driven. We report here that in Methanosarcina barkeri the driving force is a primary electrochemical sodium potential (delta mu Na+) generated by formaldehyde reduction to CH4. This is concluded from the following findings. 1. CO2 reduction to CH4 was insensitive towards protonophores, when the Na+/H+ antiporter was inhibited; under these conditions delta mu Na+ was 120 mV (inside negative), whereas both delta mu H+ and the cellular ATP content were low. 2. CO2 reduction to CH4, rather than formaldehyde reduction, was sensitive towards Na+ ionophores, which dissipated delta mu Na+. 3. CO2 reduction to CH4, in the presence of protonophores and Na+/H+ antiport inhibitors, was coupled with the extrusion of 1-2 mol Na+/mol CH4, and formaldehyde reduction to CH4 was coupled with the extrusion of 3-4 mol Na+/mol CH4. Thus during CO2 reduction to the formaldehyde level 2-3 mol Na+ were consumed.

Amiloride↗
PubMed1979

[Effects of ventilation with defined formaldehyde concentrations on lung function and lung structures. Animal experiments on the noxiousness of formaldehyde residues after disinfection in the aseptor (author's transl)].

Having seen the development of fatal pneumonias in ventilated patients, the cause of which was assumed to be the presence of residual traces of formaldehyde in the air in the respirator Kilian and Haug showed in 1973 initial formaldehyde concentrations up to 0.2 ppm in the ventilatory air of respirators correctly disinfected in the Aseptor. To study the effects of formaldehyde on lung function and lung structures, 23 young pigs were automatically ventilated with defined formaldehyde concentrations during 6 hours. The concentrations used were 0.02 ppm, 0.2 ppm and 2.0 ppm (double of the maximum permissible concentration). We found no differences in lung function, as shown by compliance measurements and arterial blood gas analysis. No radiological differences were in the thorax. Histologically, there were only slight alterations in lung structure in the group ventilated with double the maximum permissible concentration of formaldehyde. We conclude that the disinfection of respirators using formaldehyde in the Aseptor will remain the method of choice.

Animals↗
PubMed1986

Evaluation of the Du Pont Pro-Tek Formaldehyde Badge and the 3M Formaldehyde Monitor.

The 3M Formaldehyde Monitor and the DuPont Pro-Tek Formaldehyde Badge were evaluated for performance and reliability. This evaluation revealed that the 3M monitor results were variable and lower than reference concentrations determined independently. When the monitors were humidified before use and then exposed in humid (ca. 80% RH) formaldehyde-containing atmosphere, the monitors did give accurate results. Results of additional experiments led to the conclusion that quantitative reaction between formaldehyde generated in our chamber and the absorbent pad in the 3M monitor required the presence of a minimum level of absorbed water. The DuPont badges gave good agreement with the reference concentrations determined independently under the following conditions: sampling period of 1 to 12 hr with a minimum integrated sample loading of 4 ppm-hr; at least 3 m/min (10 ft/min) face velocity; correction for blank badges; and correction for loss of reagent from the samples. The evaluation indicated that the DuPont badge was not well suited to short term sampling and was subject to evaporation of liquid from the absorbing liquid blister. Blank values also were found to be variable, necessitating the analysis of several blanks to be used for blank correction with each set of samples. This blank variability also contributed to high variability found when short term measurements were made. The badge also had a negative interference from phenol at high phenol-to-formaldehyde ratios. Some of the major problems observed with both passive monitors were found only after devices which had been aged under storage conditions were analyzed and these results interpreted. If all testing had been done with fresh sampling devices, many of the problems would not have been noticed. Based on the results of this study, this factor of diffusive monitor aging needs to be addressed in any further work on passive monitor evaluation.

Air Pollutants, Occupational↗
PubMed1983

Mechanisms of antibacterial formaldehyde delivery from noxythiolin and other 'masked-formaldehyde' compounds.

Formaldehyde release in aqueous solutions of noxythiolin (N-methyl-N'-hydroxymethyl thiourea) has been monitored by nuclear magnetic resonance (n.m.r.) spectroscopy. The results suggest that antibacterial activity in such solutions resides mainly in the free formaldehyde. N.m.r. spectroscopy also demonstrated slow C-N bond rotation in noxythiolin and N-methylthiourea, with delta G of ca 15 kcal mol-1 (63 kJ mol-1). N-Hydroxymethyl imidazole is marginally more effective than corresponding hydrated formaldehyde solutions, an effect which is attributed to more rapid turnover of unhydrated formaldehyde as detected by saturation transfer n.m.r. spectroscopy. These observations are combined with the known delivery of lethal iminium ions, R2N+ = CH2, by compounds of the form R2NCH2X (X = OH, NR2; R is alkyl) to suggest a single consistent explanation of the antibacterial properties of a wide range of masked formaldehyde compounds.

Biological Assay↗
PubMed1968

Residual formaldehyde after low-temperature steam and formaldehyde sterilization.

The levels of formaldehyde remaining in various articles have been estimated immediately after a low-temperature steam and formaldehyde sterilizing process and after various periods of aeration. These levels have been compared with the levels of ethylene oxide remaining after exposure to an ethylene oxide sterilizing process. In rubber and polythene and a plastic, formaldehyde levels are low and slowly fall even further. Ethylene oxide levels are relatively much higher even after seven days' aeration. It is not considered that the residual levels of formaldehyde in rubber, polythene, and a plastic should constitute a danger. Residual levels of formaldehyde in fabrics and paper are higher but this may be of value by giving a self-disinfecting action on storage.

Air↗
PubMed1979

Measurement of formaldehyde concentrations in a subatmospheric steam-formaldehyde autoclave.

A method has been developed for measuring formaldehyde concentrations in a subatmospheric steam-formaldehyde autoclave. Data obtained using this method indicate that the concentration of formaldehyde in the chamber atmosphere is not homogeneous and that it decreases rapidly with time. The penetration of formaldehyde vapour into narrow tubes has also been investigated and was shown to be dependent on the length-to-bore ratio of the tubes. The formaldehyde concentration within the tubes could be increased by using a lower vacuum in the air removal stage at the beginning of the cycle.

Formaldehyde↗
PubMed1989

The movement of blood formaldehyde in methanol intoxication. I. A simple headspace gas chromatography-mass spectrometry for determining the amount of formaldehyde in the blood.

A gas chromatographic-mass spectrometric method for determining the amount of formaldehyde in the blood has been investigated. This method is based on the formation of diethoxymethane, which results from the reaction of formaldehyde with ethanol while in an acid state. The calibration curve in blood specimens showed a good linearity in the range of 20 to 100 microM formaldehyde with a correlation coefficient of 0.996. The minimum detectable amount of formaldehyde in the blood was found to be 10 microM and this analytic method was deemed useful for microanalysis of formaldehyde in blood.

Formaldehyde↗
PubMed1995

Occupational asthma due to formaldehyde resin dust with and without reaction to formaldehyde gas.

We report the cases of three subjects who developed asthma after being exposed to formaldehyde dust or gas. For two subjects, specific bronchial provocation tests with formaldehyde gas did not cause significant bronchoconstriction, whereas exposure to formaldehyde resin dust did. One subject experienced asthmatic reaction after being exposed to formaldehyde resin dust and gas. These findings suggest that the physical and chemical properties of formaldehyde are relevant to its likelihood of causing asthma.

Adult↗
PubMed1998

The impact of initial job assignment on formaldehyde exposure among African-American and white formaldehyde industry workers.

We compared initial job assignments of African-American and white employees at eight worksites that used formaldehyde between 1940 and 1979. Unexposed workers were excluded. Median, ambient air formaldehyde, 8-hour, time-weighted average (TWA8) exposure estimates were determined for each worksite. Job assignments with TWAs above the worksite's median TWA8 were called high formaldehyde exposed (HFE). Job assignments with TWAs less than or equal to the worksite's median TWA8 for the same period were called lower formaldehyde exposed (LFE). Two worksites assigned black workers to HFE jobs in significantly higher proportions than white workers in some decades. One worksite assigned white workers in significantly higher proportions than black workers to HFE jobs in some decades. One worksite assigned racial groups in nearly equal proportions from 1940 to 1969. The remaining sites showed insignificant assignment disproportions (alpha = 0.05; Chi-square < or = 3.841, 1 degree of freedom) for any period. No major trend was apparent across all plants and decades.

Black or African American↗
PubMed1991

Kinetics and mechanism of methanol and formaldehyde interconversion and formaldehyde oxidation catalyzed by liver alcohol dehydrogenase.

It has been shown that the hydrophobic interaction in the active-site plays a fundamental role in substrate binding. Proper molecular orientation is required for hydride transfer (Dalziel and Dickinson, 1967). For methanol, the binding is unfavored due to the lack of a hydrophobic chain. In the enzyme-coenzyme-substrate complex, the small methyl group of the substrate is not held in a fixed position, resulting in a low hydride transfer rate. The binding of NAD+ to the enzyme does not exhibit a significant effect on the binding of methanol, nor does methanol affect NAD+ binding. In the presence of LADH, methanol is oxidized by NAD+ to formaldehyde, while formaldehyde can be oxidized by NAD+ to formate ion or reduced by NADH to methanol. These reactions follow a rapid equilibrium random mechanism. Among these three reactions, the reduction of formaldehyde is the most rapid. The rate of formaldehyde oxidation is faster than the oxidation of methanol. Our study with these non-hydrophobic substrates provides an important bridge between the bioinorganic activation of zinc-bound water and the bioorganic oxidation of ethanol. Furthermore, it furnishes some insight into an enzymatic system that is so highly sensitive to small changes in substrate chain length that it can magnify the consequence of a modest change in substrate hydrophobicity.

Alcohol Dehydrogenase↗
PubMed1996

Biological indicators for low temperature steam and formaldehyde sterilization: investigation of the effect of change in temperature and formaldehyde concentration on spores of Bacillus stearothermophilus NCIMB 8224.

Five strains of Bacillus stearothermophilus have been studied to identify a spore strain to be used as a biological indicator organism for low temperature steam and formaldehyde sterilization. Three strains gave poor reproducibility of batch size and growth index and were discarded. The other two strains gave good reproducibility with a high growth index and gave rise to linear survivor curves when exposed to 5% aqueous formaldehyde. However, only NCIMB 8224 sporulates on a simpler medium and as it was the most resistant to formaldehyde, it was further studied. Tests were carried out in a modified miniclave and factors studied included temperature of the steam and formaldehyde concentration. All studies confirmed the suitability of this strain as a biological indicator organism.

Data Interpretation, Statistical↗
PubMed1981

Chemosorption sampling and analysis of formaldehyde in air. Influence on recovery during the simultaneous sampling of formaldehyde, phenol, furfural and furfuryl alcohol.

A method based on trapping formaldehyde on a 2,4-dinitrodinitrophenylhydrazine-coated porous polymer (Amberlite XAD-2) was evaluated for air sampling in occupational environments. The aldehyde is converted to its 2,4-dinitrophenylhydrazone on the adsorbent. The influence of some organic compounds which often occur together with formaldehyde-furfural, phenol and furfuryl alcohol--was studied. The results show that the method allows the sampling of formaldehyde in the range 0.01--1.0 mg/m3 of air, based on a 3-1 (15 min) sample and a coating of 1%. Furfural, phenol, and furfuryl alcohol do not interfere and may be conveniently sampled at the same time. Formaldehyde and furfural hydrazones were analyzed by high-performance liquid chromatography, phenol and furfuryl alcohol by gas chromatography.

Air Pollution↗
PubMed1976

Protection against toxic effects of formaldehyde in vitro, and of methanol or formaldehyde in vivo, by subsequent administration of SH reagents.

Rapid and progressive inactivation in vitro of both alcohol dehydrogenase and aldehyde dehydrogenase by low concentrations of acetaldehyde or formaldehyde is illustrated. This inactivation can be prevented or reversed by glutathione or other SH reagents. Those effects led to investigations in vivo. Rats and mice were injected with concentrations that would result in death in approximately 10 h (methanol) and approximately 4 h (formaldehyde). When 2,3-dimercaptopropanol (BAL), cysteine, or mercaptoethanol was injected (10 min to 3 h) after administration of methanol or formaldehyde, approximately 70% of the animals survived indefinitely; the remaining 30% showed substantial increase in survival time. The findings indicate the possibility of using reagents such as BAL for human therapy and suggest that the toxicity of methanol and formaldehyde is due in part to effects other than acidosis.

Alcohol Oxidoreductases↗
PubMed1989

Disinfection with gaseous formaldehyde. Second Part: Influence of test materials on formaldehyde residues and the bactericidal and sporicidal effectiveness.

The pararosaniline method for the determination of formaldehyde residues on test surfaces after exposure to gaseous formaldehyde was standardized as well as the methods of collection, preparation and desorption from the samples. The analysis of residues on plates of 5 different materials yielded the following amounts of residues after 60 minutes exposure to 3.2 mg HCHO1-1 air at 45 degrees C and a relative humidity (RH) of about 90%; silicon rubber 287.2 micrograms, lacquered polyurethane foam 109.6 micrograms, lacquered aluminium 30.3 micrograms, plexiglass 13 micrograms and stainless steel 4 micrograms HCHO 100 cm-2. The residues of formaldehyde on lacquered aluminum after an HCHO exposition with condensing layer at 20 and 30 degrees C were 10(3)-fold higher than after an exposition to gaseous formaldehyde without a condensing layer at a relative humidity of about 90% and a temperature of 40 degrees C. The inactivations of S. aureus and Bacillus subtilis spores on carriers of 5 different materials were determined under the same conditions (60 min, 3.2 mg HCHO 1-1 air, 45 degrees C and a RH of about 90%). The decimal reductions showed that Staphylococcus aureus ATCC 6538 was more readily inactivated on non porous plexiglass with a D-value of 0.7 min or stainless steel D = 1.1 min than on porous silicon rubber D = 3 min. For spores of Bacillus subtilis var. niger DSM 675, D-values of 1.6 min for plexiglass, 2.3 min for stainless steel, 2.7 min for lacquered aluminium, 3.2 min for lacquered polyurethane foam and 4.1 min for silicon rubber were registered.

Bacillus subtilis↗
PubMed1989

Disinfection with gaseous formaldehyde. Fourth Part: Influence of aeration on the level of formaldehyde residues.

After a formaldehyde exposition of 100 cm2 aluminium plates covered with a structured lacquer during 60 min at 40 degrees C and relative humidity of about 90% in a model chamber formaldehyde residues of 9.5, 21.9 and 57 micrograms HCHO 100 cm-2 were recorded for plates exposed respectively to 0.75, 1.5 and 3.2 mg HCHO l-1 air. In the model chamber tempered at 40 degrees C the reduction of the HCHO residues after an additional 60 min ventilation with an internal air circulation was 63%. After a passive aeration for 60 min in a room at ambient temperature (24 +/- 3 degrees C) without ventilation the formaldehyde residues decreased by 70-74%. In a heating cabinet tempered at 40 degrees C after an internal active aeration of 60 minutes the residual formaldehyde diminished by 76-82%.

Disinfection↗
PubMed1984

Respiratory response to formaldehyde and off-gas of urea formaldehyde foam insulation.

In 18 subjects, 9 of whom had previously complained of various nonrespiratory adverse effects from the urea formaldehyde foam insulation (UFFI) in their homes, pulmonary function was assessed before and after exposure in a laboratory. On separate occasions formaldehyde, 1 part per million (ppm), and UFFI off-gas yielding a formaldehyde concentration of 1.2 ppm, were delivered to each subject in an environmental chamber for 90 minutes and a fume hood for 30 minutes respectively. None of the measures of pulmonary function used (forced vital capacity, forced expiratory volume in 1 second or maximal midexpiratory flow rate) showed any clinically or statistically significant response to the exposure either immediately after or 8 hours after its beginning. There were no statistically significant differences between the responses of the group that had previously complained of adverse effects and of the group that had not. There was no evidence that either formaldehyde or UFFI off-gas operates as a lower airway allergen or important bronchospastic irritant in this heterogeneous population.

Allergens↗
PubMed1982

[Chromosome damages in human lymphocytes as affected by formaldehyde. I. Formaldehyde treatment of lymphocytes in culture].

The cytogenetic activity of formaldehyde was studied in human lymphocytes in vitro. High concentrations of formaldehyde (0.01 mg/ml, 2.5, and 5 mg/l) inhibit mitotic activity of cells to induce polyploidy and chromosome aberrations with high frequency at G2-stage of mitotic cycle. In comparatively low concentrations formaldehyde does not inhibit cell proliferation, and induces chromosome aberrations at G1-S-stages, but not at G2-stage of mitotic cycle. Specific effect of formaldehyde on the distribution of damages pro genome and pro chromosome was also observed.

Cells, Cultured↗