Eric B. Sansone

Ethidium bromide: Destruction and decontamination of solutions

Ethidium bromide in water, TBE buffer, Mops buffer, and cesium chloride solution may be completely degraded by reaction with sodium nitrite and hypophosphorous acid. Only non-mutagenic reaction mixtures were produced. Destruction was greater than 99.8% in all cases; the limit of detection was 0.5 micrograms ethidium bromide per milliliter of solution. Ethidium bromide also may be removed completely from the above solutions by using Amberlite XAD-16 resin. The limit of detection was 0.05 micrograms ethidium bromide per milliliter of solution (0.27 micrograms/ml when cesium chloride solution was used).

Oxidation of 1,1-dimethylhydrazine (UDMH) in aqueous solution with air and hydrogen peroxide

The degradation of 1,1-dimethylhydrazine (UDMH), a component of some rocket fuels, was investigated using atmospheric oxygen and hydrogen peroxide. The reactions were carried out in the presence and absence of copper catalysis and at varying pH. Reactions were also carried out in the presence of hydrazine, a constituent, along with UDMH, of the rocket fuel Aerozine-50. In the presence of copper, UDMH was degraded by air passed through the solution; the efficiency of degradation increased as the pH increased but the carcinogen N-nitrosodimethylamine (NDMA) was formed at neutral and alkaline pH. Oxidation was not seen in the absence of copper. Production of NDMA occurred even at copper concentrations of < 1 ppm. Oxidation of UDMH with hydrogen peroxide also gave rise to NDMA. When copper was absent degradation of UDMH did not occur at acid pH but when copper was present some degradation occurred at all pH levels investigated. The production of NDMA occurred mostly at neutral and alkaline pH. In general, higher concentrations of hydrogen peroxide and copper favored the production of NDMA. Dimethylamine, methanol, formaldehyde dimethylhydrazone, formaldehyde hydrazone, and tetramethyltetrazene were also produced. The last three compounds were tested and found to be mutagenic.

The Effect of Moisture on the Adsorption of Chloroform by Activated Carbon

The effect of moisture on the ability of a granular activated carbon to adsorb chloroform vapor from a flowing airstream was studied under three test conditions: (1) chloroform and water vapor were introduced concurrently into a dry carbon bed; (2) dry chloroform was introduced into a humidified carbon bed; (3) humidified chloroform was introduced into a carbon bed at the same relative humidity. The criterion for bed performance was the time when the downstream chloroform concentration was 1% of that in the inlet stream. Chloroform concentration was essentially constant at 108 +/- 2 micrograms/cm3; relative humidities (RH) varied from 0 to 97%. No RH effect on the adsorption of chloroform by the carbon was observed in test (1); tests (2) and (3) showed monotonic decreases in chloroform adsorption for RH greater than 40%. These results indicated that, for a dry carbon bed, the 1% breakthrough time for chloroform adsorbed from atmospheres of RH from 13% to 95% was essentially the same as that when RH = 0%. For humidified carbon beds, no change in 1% breakthrough time for chloroform was observed until RH was greater than 40%.

Prediction of adsorption rate constants of activated carbon for various vapors

Abstract In the past decade, a theoretical calculation of the adsorption properties of activated carbon has successfully been used to predict the adsorption capacity for untested vapors after initial characterization of the carbon with a reference vapor. However, using this theoretical approach, it has not been possible to predict the second fundamental property of carbons, namely its adsorption rate constant, and therefore only a family of curves for adsorption performance could be calculated. A new extension of the present theory is proposed which would permit prediction of the adsorption rate constant of vapors, after initial characterization of the carbon with a reference vapor, so that a curve of adsorption performance can be calculated for any vapor needed.

Notes. Reductive destruction of hydrazines as an approach to hazard control

Hydrazine and 14 of its monoand disubstituted alkyl, aryl, and acyl derivatives were quantitatively destroyed by using either of two nickel-based catalytic reductive procedures. Small volumes of solutions containing hydrazines were made alkaline and treated with aluminumnickel powder; large volumes were treated with preformed Raney nickel with or without an exogenous hydrogen source. No interference was discovered except from acetone. The only products detected were ammonia and the amines corresponding to the hydrazine reduced. No benzidine could be detected when 1,2-diphenylhydrazine was reduced. These procedures appear to provide a reliable, efficient, one-step approach to conversion of potentially carcinogenic hydrazines to innocuous products in laboratory wastes or in the environment.

Potential hazards from feeding test chemicals in carcinogen bioassay research

Abstract Sodium fluorescein was added to the meal diet of 188 of 704 rats housed in one room. Its spread over an 8-day period is described. All normal operations led to contamination of clothing and equipment. All surfaces of the experimental room, clean corridor, and return corridor were contaminated. The results suggest that, during feeding of hazardous materials to animals, personnel may be exposed and crosscontamination of animals may occur; improvements are suggested.

The Safe Disposal of Diaminobenzidine

Abstract Diaminobenzidine is a mutagen and possible carcinogen which is widely used in microscopy. The disposal of unneeded bulk quantities and aged working solutions is a problem for many laboratories. A number of methods for the treatment of diaminobenzidine for safe disposal were evaluated. The methods tested were oxidation with potassium permanganate in sulfuric acid, treatment with hydrogen peroxide in the presence of horseradish peroxidase, treatment with sodium hypochlorite, and treatment with sodium nitrite and hypophosphorous acid. The methods were tested to see that the compound was completely degraded and that only nonmutagenic reaction mixtures were produced. Two methods can be recommended for general use: destruction using potassium permanganate or using hydrogen peroxide in the presence of horseradish peroxidase. These procedures can be used for diaminobenzidine in tris(hydroxymethyl) aminomethane or phosphate buffer or for bulk quantities. The diaminobenzidine is completely destroyed (less ...

Oxidative Destruction of Hydrazines Produces N-Nitrosamines and Other Mutagenic Species

As part of the joint International Agency for Research on Cancer-National Cancer Institute program for the evaluation and development of methods for the degradation of chemical carcinogens, four oxidative techniques for the degradation of hydrazines were investigated. The oxidizing agents used were as follows: sodium hypochlorite, calcium hypochlorite, potassium iodate, and potassium permanganate in sulfuric acid. In each case, at least 99% of the hydrazine initially present was destroyed; however, the potential usefulness of these methods was compromised by the formation (in some reaction mixtures) of carcinogenic N-nitroso compounds and/or unknown mutagenic species. Oxidative degradation of hydrazines is recommended only for the decontamination of glassware and for the treatment of spills, for which reductive degradation methods are not suitable.

Decontamination of Aqueous Solutions of Biological Stains

Aqueous solutions of a number of biological stains were completely decontaminated to the limit of detection using Amberlite resins. Amberlite XAD-16 was the most generally applicable resin but Amberlite XAD-2, Amberlite XAD-4, and Amberlite XAD-7 could be used to decontaminate some solutions. Solutions of acridine orange, alcian blue 8GX, alizarin red S, azure A, azure B, Congo red, cresyl violet acetate, crystal violet, eosin B, erythrosin B, ethidium bromide, Janus green B, methylene blue, neutral red, nigrosin, orcein, propidium iodide, rose Bengal, safranine O, toluidine blue O, and trypan blue could be completely decontaminated to the limit of detection and solutions of eosin Y and Giemsa stain were decontaminated to very low levels (less than 0.02 ppm) using Amberlite XAD-16. Reaction times varied from 10 min to 18 hr. Up to 500 ml of a 100 micrograms/ml solution could be decontaminated per gram of Amberlite XAD-16. Fourteen of the 23 stains tested were found to be mutagenic to Salmonella typhimurium. None of the completely decontaminated solutions were found to be mutagenic.

Destruction of cyanogen bromide and inorganic cyanides.

Cyanogen bromide in water and seven organic solvents and sodium cyanide in water may safely and efficiently (greater than 99.7%) be destroyed using sodium hydroxide (1 M) solution and commercially available sodium or calcium hypochlorite. Details are given of an analytical procedure which can be used to check the final reaction mixture for the presence of residual cyanogen bromide or cyanide.