Rajinder S. Narang

Subchronic exposure of mice to Love Canal soil contaminants.

The health hazard potential of soil collected from the surface of the Love Canal chemical dump site in Niagara Falls, New York, was assessed in 90-day exposure studies. Female CD-1 mice were exposed to two concentrations of the volatile components of 1 kg of soil with and without direct soil contact. Control mice were identically housed but without soil. The soil was replaced weekly and 87 compounds were detected in the air in the cages above fresh and 7-day-old soil as analyzed by gas chromatography/mass spectrometry. The concentration of many of these compounds decreased during the 7-day exposure cycle. Histopathologic, hematologic, and serum enzyme studies followed necropsy of all mice. There was no mortality of mice exposed for up to 90 days under any condition. Thymus and spleen weights relative to body weight were increased after 4 weeks of exposure by inhalation but not after 8 or 12 weeks of exposure. alpha-, beta-, and delta- Benzenehexachlorides , pentachlorobenzene, and hexachlorobenzene were detected in liver tissue from these animals. Mice exposed to 5- to 10-fold elevated concentration of volatiles had increased body and relative kidney weights. There was no chemically induced lesion in any animal exposed only to the volatile soil contaminants. Mice exposed by direct contact with the soil without elevated volatile exposure had increased body (10%) and relative liver weights (169%). Centrolobular hepatocyte hypertrophy, which involved 40 to 70% of the lobules, was observed in all mice in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Tetrachloroethylene (PCE, Perc) levels in residential dry cleaner buildings in diverse communities in New York City.

Fugitive tetrachloroethylene (PCE, perc) emissions from dry cleaners operating in apartment buildings can contaminate residential indoor air. In 1997, New York State and New York City adopted regulations to reduce and contain perc emissions from dry cleaners located in residential and other buildings. As part of a New York State Department of Health (NYSDOH) study, indoor air perc levels were determined in 65 apartments located in 24 buildings in New York City where dry cleaners used perc on site. Sampling occurred during 2001–2003, and sampled buildings were dispersed across minority and nonminority as well as low-income and higher income neighborhoods. For the entire study area, the mean apartment perc level was 34 μg/m3, 10-fold lower than mean apartment levels of 340–360 μg/m3 documented before 1997. The maximum detected perc level was 5,000 μg/m3, 5-fold lower than the maximum of 25,000 μg/m3 documented before 1997. Despite these accomplishments, perc levels in 17 sampled apartments still exceeded the NYSDOH residential air guideline of 100 μg/m3, and perc levels in 4 sampled apartments exceeded 1,000 μg/m3. Moreover, mean indoor air perc levels in minority neighborhoods (75 μg/m3) were four times higher than in nonminority households (19 μg/m3) and were > 10 times higher in low-income neighborhoods (256 μg/m3) than in higher income neighborhoods (23 μg/m3). Logistic regression suitable for clustered data (apartments within buildings) indicated that perc levels on floors 1–4 were significantly more likely to exceed 100 μg/m3 in buildings located in minority neighborhoods (odds ratio = 6.7; 95% confidence interval, 1.5–30.5) than in nonminority neighborhoods. Factors that may be contributing to the elevated perc levels detected, especially in minority and low-income neighborhoods, are being explored.

Combustion of flame retardants II

Combustion of 2,4,6-tribromoaniline as such, in the presence of antimony trioxide and two solvents, was carried out in a tubular furnace in the presence of a natural gas/oxygen flame. The effect of temperature, residence time, and level of oxygen on the yields of different toxic products formed was studied.

Pyrolysis and combustion of liquids and solids containing pentachlorophenol

The effect of concentration, residence time, and matrix on the formation of PCDDs/PCDFs from the combustion of pentachlorophenol in the presence of a flame and from its pyrolysis at atmospheric pressure was studied.

Thermally induced formation of PCDD and PCDF from tri- and tetrachlorobenzene in dielectric fluids

Abstract The thermal behavior of dilute (5000-50 ppm) solutions of tri- and tetrachlorobenzene in mineral oil, silicone oil, and tetrachloroethylene (TCE) has been investigated. Although pyrolyses or combustion of neat chlorobenzenes readily forms significant yields of PCDDs/PCDFs, corresponding treatment of dilute solutions was generally non-productive. This result is consistent with the proposition that, under the conditions studied, the rate-limiting step for PCDD/PCDF formation is bimolecular in chlorobenzene. In contrast, earlier studies of PCBs implied a rate-limiting step that was unimolecular in chloroaromatics. Combustion of dilute solutions of chlorobenzenes in tetrachloroethylene did produce detectable concentrations of PCDF; this result reflects combination of chlorobenzene and TCE- or TCE-derived species.

Thermally-induced formation of polychlorinated dibenzofurans from Aroclor 1254 contaminated silicone oil and tetrachloroethylene

Abstract Pyrolysis of solutions of Aroclor 1254 at atmospheric pressure and its combustion in the presence of a flame in a tubular flow furnace was carried out. The effect of temperature and residence time on the formation of PCDFs in two different solvent matrices was investigated.

A simplified method for the determination of volatiles in eggs using headspace analysis with a photoionization detector

Headspace sampling of whole eggs at 50°C was used to determine benzene, toluene, trichloroethene, tetrachloroethene, chlorobenzene, ethylbenzene, ortho-, meta-, and para-xylenes as sources of contamination. A 30-m, 0.53-mm ID fused silica capillary column coated with 1.0 μm (5%) methyl silicone attached to a photoionization detector was used to separate and detect the volatiles. The sensitivity of the method was 0.002 μg/mL with an average precision for all nine compounds of 16.5 ±3.1% (n = 10) for a 0.01 μg/ml standard.

Formation of bromodioxin analogs from closed tube pyrolysis of 2,4,6-tribromoaniline (I)

Abstract Closed-tube pyrolysis of 2,4,6-tribromoaniline (TBAn) produced polybromophenazines (PBPZs). The identities of these compounds were supported by matching their mass spectra with the mass spectra of brominated phenazines and by the formation of phenazine from the pyrolysis of aniline under the same conditions. Tetrabromophenazine (T4BPZ) was isolated from the pyrolysis by-products by using activated acid alumina column. An in vitro study showed that T4BPZ exhibits dioxin-like activity.

Determination of Aldehydes, Ketones, Esters, and Ethers in Air Using Porapak N and Charcoal

A method was developed to determine aldehydes, ketones, esters, and ethers in air which is simple, efficient, and sensitive. Analytes are trapped on a glass cartridge filled with 4 in of Porapak N followed by 1 in of charcoal. These are eluted with 1 ml of methanol, and the eluate is injected onto a gas chromatograph equipped with a photoionization detector (PID). Quantitation is performed by measuring the peak height or area of each analyte of interest and comparing it with a standard in methanol. These cartridges can be reused a number of times after reconditioning. This method is efficient since it lends itself to the use of an autosampler, which can inject large numbers of samples onto the gas chromatograph while it is unattended.The method detection limit was from 0.6 to 16.5 μg/m3, which is comparable to other methods, and recoveries ranged from 83 to 120%. The sensitivity from highest to lowest, with respect to class of compound, was determined to be aldehydes, ketones, esters, and ethers. Up to 150 L of air can be passed onto the cartridge without any expected breakthrough of analytes, as opposed to only 10 to 30 L with 1 in of charcoal alone, which is normally the adsorbent of choice.

Formation of brominated dioxins and brominated phenazines from pyrolyses of 2,4,6-tribromoaniline and N-(tribromophenyl) maleimide

Abstract Antimony (III) oxide (Sb 2 O 3 ) was found to cause an initial increase of the bromodioxin analog, tetrabromophenazine, in the pyrolysis of 2,4,6-tribromoaniline. At higher concentrations of Sb 2 O 3 and at longer residence time, Sb 2 O 3 addition decreased the amount of tetrabromophenazine. Also, the pyrolyses of the flame retardant preparation, N-(tribromophenyl) maleimide and 2,4,6-tribromoaniline were found to produce tetrabromophenazine, tribromophenazine, tetrabromodioxins and tetrabromofurans.