Application of an automated HS-GC method in partition coefficient determination for xylenes and ethylbenzene in rat tissues.

An automated static head space-gas chromatography method was used in the determination of partition coefficients (Kd) for the xylene isomers and ethylbenzene in blood, brain, muscle, kidney, liver and fat of Sprague Dawley rats. Since homogenization resulted in the potential loss of analytes from tissue samples, unhomogenized samples were used. With a few exceptions, tissue:air Kd values were independent of the concentrations of the analytes, singly or as a mixture. The tissue:blood Kd values were determined. For each tissue and analyte, the value obtained for each analyte concentration was within +/- 10% of the mean value calculated for the entire concentration range.

Sonication of aqueous solutions of chlorobenzene.

Sonication at two frequencies (20 and 900 kHz) was carried out on dilute (220 ppm) aqueous solutions of chlorobenzene. The formation of chloride ions was followed using ion chromatography. The solutions became more colored with time; the absorbance maximum was around 270 nm. Some of the compounds remaining in the solution could be identified; they were chlorinated phenols, chloronaphthalene, mono and dichlorobiphenyls, etc. At the same acoustic power, the rate of chloride formation with 20 kHz ultrasound was greater when a probe with a larger tip area was used, but significantly less than the rate with 900 kHz. The use of ultrasound for conversion of chlorine in organic compounds in water to chloride can thus be performed more efficiently using a higher frequency and with a lower intensity (power per area). There is, however, a possibility that the toxicity of the aqueous solution is increased by such treatment.

The effect of frequency on sonochemical reactions III: dissociation of carbon disulfide.

Investigations were made of the effects of frequency, temperature, intensity and gases on the rate of sonochemical dissociation of carbon disulfide. Application of 900 kHz ultrasound did not produce any noticeable change. When carbon disulfide was irradiated with 20 kHz, the liquid formed a heterogeneous mixture of black particles in a yellow solution. The rate of dissociation decreased with increasing temperature, in agreement with most sonochemical reactions. The rate also decreased with decreasing area of the horn tip, keeping total power constant. This dependence on the horn tip area, as well as that on the frequency, is in opposition to the dependence for the formation of iodine from the sonication of aqueous potassium iodide solution [See Part II, Ultrasonics Sonochemistry 3 (1996) 19]. The X-ray spectrum of the black particles and the yellow residue obtained after evaporation showed the presence of amorphous carbon and monoclinic sulfur. The rate of sono-dissociation of carbon disulfide in the presence of different gases is in the order He > H2 > Air > Ar > O2 > CO2.

Measurement of the distribution of m-xylene in rat tissues by head space gas chromatography.

An automated head space-gas chromatography (HS-GC) method was developed and evaluated for reliability in measurement of m-xylene in rat tissues. For tissue samples spiked with m-xylene (n = 2), the analytical precision was better than 12% relatives standard deviation (RSD) over the concentration range of 0.1 to ca 100 micrograms/g for liver and kidney, 0.1 to 170 micrograms/g for brain, 1.2 to 250 micrograms/g for fat, and 0.006 to 50 micrograms/mL for blood. For rats sacrificed immediately after an acute exposure to 1100 ppm of m-xylene, the relative tissue m-xylene concentrations were in the ascending order as follows: brain < or = blood < or = kidney < liver << fat. A precision of < 13% RSD was generally obtained for duplicate tissue samples from exposed animals, with m-xylene concentrations of about 10 micrograms/g of tissue.

Environmental health and monitoring in Estonia.

An assessment of environmental health and monitoring in Estonia after the dissolution of the Soviet Union has shown that the country suffered from neglect during the "cold war" after World War II, and efforts to improve the status quo have been slow since independence was gained in 1991. Conditions in Estonia are affected by the fifty-year long occupation. Industrial, military and agricultural activities have left a legacy of pollution and obsolete installations. The regulatory framework and life style attitudes from the Soviet era interfere with reform efforts. The current transition period holds risks that derive from a run-down infrastructure, a weak economy, and disruptions, inherent in the reorganization itself. Over the past few years a recession has further complicated the situation and the public health status has worsened. International assistance programmes as well as efforts by Estonians have led to some change and progress in environmental management since 1991, and lately ambitious environmental and public health sector programmes have been initiated by the government. Much work, however, still needs to be done. An examination of the recent history of this small country provides examples of environmental neglect and consequences, as well as recommended corrective measures.

An automated head space analysis method for xylenes and ethylbenzene in blood and water.

A sensitive, reliable method of analysis was established for water and blood samples containing xylene isomers (m-,o- & p-) and ethylbenzene by means of an automated head space sampler connected to a GC equipped with a flame ionization detector. Minimum detection limits (MDLs) were ca. 1 and 6 ng/mL, respectively, for each of the four target compounds in water and blood samples. Practical quantitation limits (PQLs) with precision values better than +/- 4% for duplicate samples were 40 and 240 ng/mL, respectively, for the individual organic compounds in water and blood. The analytical precision was < +/- 4% for concentrations above the PQL and up to 50 micrograms/mL. Calibration curves for the C2-benzene isomers in water and blood samples were linear (r2 > 0.9999) for individual analyte concentration up to ca. 50 micrograms/mL. Blank values were below the MDLs. The effect of cocontaminants on head space analyte concentration was insignificant for the anticipated range of sample composition.

Mutagenicity and chemical analysis of sequential organic extracts of airborne particulates.

To obtain insight into the identity of chemicals associated with the mutagenicity of United States National Institute of Standards and Technology (NIST) Standard Reference Materials SRM 1649 (urban dust) and SRM 1650 (diesel particulate), parallel mutagenicity tests and chemical analyses were performed on dichloromethane and sequential organic extracts of these samples. SRM 1649 and 1650 were sequentially extracted with five organic solvents of increasing polarity, in order to partition mutagenic components into discrete fractions. The solvents (with associated polarity index) were as follows: (1) hexane (0.0); (2) hexane:diethyl ether 9:1 (0.29); (3) hexane:diethyl ether 1:1 (1.45); (4) diethyl ether (2.9); (5) methanol (6.6). 0.9270 g of SRM 1649, and 0.0510 g of SRM 1650 were each extracted three times with 8 ml of each of the solvents, the three aliquots were pooled, and analysed for target organics or solvent-exchanged into DMSO for mutagenicity testing in Salmonella typhimurium strains TA98 and TA100. The dichloromethane extracts of SRM 1649 and SRM 1650 contained direct-acting mutagens in Salmonella strains TA98 and TA100; SRM 1650 was significantly more potent than SRM 1649 in either strain. Addition of S9 caused a large decrease in mutagenicity of each extract, although SRM 1650 remained more potent. An interesting pattern of mutagenicity was observed for the sequential extracts of SRM 1649 and SRM 1650: the mutagenic potency of SRM 1649 extracts increased with increasing polarity of the extraction solvent while the response of the SRM 1650 extracts was the opposite. This suggests that the direct-acting mutagens in SRM 1650 are unlike those in SRM 1649. The response, though diminished, was largely unchanged when S9 was included in the test mixture. Chemical analyses on the various extracts were performed using a Hewlett-Packard model 5890 gas chromatograph equipped with a model 5970B mass selective detector (GC-MSD), and a 0.3 microns film thickness cross-linked methyl silicone capillary column (HP 1909A-101). Selected ion monitoring (SIM) methods were used to analyze for 105 target compounds including PAHs and nitro-PAHs. Chemical analysis of the dichloromethane extracts of SRM 1649 and SRM 1650 identified three main classes of compounds: polyaromatic hydrocarbons (PAH), nitro-polyaromatic hydrocarbons (NO2-PAHs) and heterocyclics. The concentration of target compounds and the proportion of nitro-PAHs and heterocyclic compounds were considerably greater in SRM 1650 than in SRM 1649, consistent with the observed differences in their mutagenic potency. However, the different responses of the dichloromethane extracts in TA98 and TA100 suggest the presence of different (unidentified) compounds.(ABSTRACT TRUNCATED AT 400 WORDS)

Short-term dermal toxicity and mutagenicity of coal coprocessing products in the rat.

The present study was conducted to determine the dermal toxicity of coal coprocessing products and to assess their potential health hazards. Groups of 10 male and 10 female Sprague-Dawley rats were administered dermally coal coprocessing products (light gas oil, LGO; heavy gas oil I, HGOI; heavy gas oil II, HGOII) at 1 g/kg body weight/d for 14 d. The control and positive control groups received normal saline and a coal liquefaction product (CLP) at the same dose level, respectively. Treatment with either the three fractions of coprocessing products or CLP caused decreased growth rate and food consumption in animals of both sexes. Liver enlargement occurred in groups treated with HGOI, HGOII, and CLP. Decreased serum glucose was observed in animals of both sexes treated with the three fractions and CLP. Treatment with HGOI and CLP caused an elevation of hepatic microsomal ethoxyresorufin deethylase activity in the rat of both sexes. The three fractions and CLP caused mild anemia. Mild treatment-related histological changes were observed in the liver, spleen, thyroid, bone marrow, and kidney. All three fractions of coprocessing products were tested for their mutagenicity in five strains of Salmonella typhimurium: TA98, TA100, TA1535, TA1537, and TA1538. HGOI, after metabolic activation, was found to be mutagenic in the strains of TA98, TA100, and TA1538. In contrast, HGOII was mutagenic in the five strains with or without metabolic activation. These data indicate that HGOI and HGOII are more toxic than LGO, and should be subjected to further studies to determine their long-term effects.

Subacute inhalation toxicity of a medium-boiling coal liquefaction product (154-378 degrees C) in the rat [Part III].

The short-term inhalation toxicity of a medium-boiling coal liquefaction product (CLP) was investigated in the rat. Groups of 5 male and 5 female Sprague-Dawley rats were exposed to CLP aerosols at 25 mg/m3 (low dose) or 100 mg/m3 (high dose) 6 h/d, 5 d/w, for 4 wk. The control group was exposed to filtered air while the positive control received diesel fuel aerosols at 100 mg/m3. Male rats exposed to high-dose CLP aerosols exhibited growth depression and increased hepatic aminopyrine demethylase activity compared to control animals. High-dose females had decreased hemoglobin content and hematocrit values. These biochemical and hematological effects were not observed in animals of either sex treated with the diesel fuel. No other biochemical and hematological changes were observed. Mild histological changes occurred in the liver and thyroid of rats treated with CLP and diesel fuel aerosols. Based on the data presented, inhalation of CLP aerosols resulted in toxicological effects that were similar to those caused by dermal exposure.

A review of techniques for measurement of airborne aldehydes.

The literature on aldehyde measurement methods was surveyed and critically reviewed to determine which methods would prove most suitable for monitoring personal exposure to a number of aldehyde compounds that have been found in air. A variety of methods was found that were applicable to measurement of specific aldehydes. Some of these were based on instrumental and spectrophotometric analytical methods. Others, based on direct sorption of aldehydes on solid sorbents with subsequent instrumental analysis, were developed and validated only for one or two aldehydes in air. The most promising techniques involved derivatization with one of several available agents (e.g., N-benzylethanolamine, 2,4-dinitrophenylhydrazine) and, most commonly, extraction and analysis using chromatographic (HPLC or GC) instrumentation. Even these, however, were not found to be fully validated methods suitable for the concurrent measurement of several aldehydes.

Dermal toxicity of a medium-boiling (154-378 degrees C) coal liquefaction product in the rat--Part I.

The subchronic dermal toxicity of a medium-boiling coal liquefaction product (CLP, 154-378 degrees C) was investigated in the rat. CLP was applied to the shaved backs of rats at dose levels of 50, 100, 200, or 400 mg/kg body weight.d, 7 d/wk for a period of 13 wk. Control groups received 0.4 ml/kg of normal saline. Signs of dermal irritation were observed at sites of application in males dosed at 200 and 400 mg/kg body weight and were characterized by thickened, focally necrotic and ulcerative skin. All animals survived the full length of the treatment period. Growth depression was observed in males at all dose levels, but no significant decrease in weight gain was observed in females. An increase in liver/body weight ratios was observed in all treatment groups of both sexes. The organ/body weight ratios for the spleen, heart, kidney, and brain were also increased in the upper dose groups of both sexes. Treatment with CLP caused a dose-dependent decrease in hemoglobin and packed cell volume in both sexes of all dose groups. The number of erythrocytes was decreased and that of neutrophils was increased in some CLP-treated groups of both sexes. There was a mild myeloid hyperplasia with increased myeloid/erythroid ratios in the 200- and 400-mg/kg groups of both sexes. Hepatic microsomal ethoxyresorufin deethylase activity was increased in all treatment groups of females, and in males dosed at 100 mg/kg and higher. In the renal tubules mild treatment-related histological changes occurred, which consisted of eosinophilic inclusions, increased cytoplasmic volume, and pyknosis. These changes were noted in the high-dose groups of both sexes. These data indicate that the medium-boiling CLP could produce systemic toxicity when applied dermally at 50 mg/kg body weight.d.

Dermal toxicity of a high-boiling (bp 250-450 degrees C) coal liquefaction product in the rat--II.

Coal liquefaction products have been considered as an alternate source of energy to replace conventional crude oil. The present study was designed to investigate the dermal toxicity of a heavy fraction of coal liquefaction product (CLP, bp 250-450 degrees C) in the rat. Groups of 10 male and 10 female Sprague-Dawley rats (180-200 g) were treated dermally with CLP at dose levels of 100, 200, 400, or 800 mg/kg body weight.d for 6 wk. The controls were treated with 0.4 ml/kg of normal saline, while the positive control group received 400 mg/kg diesel fuel. Growth suppression was observed in all CLP-treated groups of males; in the females this effect occurred in the two highest dose groups. Diesel fuel at 400 mg/kg also caused growth suppression of a similar magnitude to that of CLP in male rats. Male animals treated with high doses of CLP or diesel fuel had severe skin lesions. Increased liver weights were observed in the diesel fuel-treated as well as all CLP-treated groups of females. The kidney weights of females treated with 400 mg/kg and 800 mg/kg CLP were also higher than control values. Decreased red cell count, hemoglobin, and hematocrit volume occurred in some CLP and diesel fuel groups of both sexes. There was mild bone marrow hyperplasia in rats of both sexes treated with CLP or diesel fuel. Mild histological changes were observed in the thyroid, liver, bone marrow, and skin of rats of both sexes treated with CLP and diesel fuel. Based on the data presented, dermal application of CLP produced systemic toxicity at the dose levels studied, and CLP and diesel fuel possess toxic effects of similar nature and magnitude.

Fabric protectors. Part I - Evaluation of a grab sampling technique for determination of organic vapors.

A grab sampling technique utilizing evacuated glass sampling bulbs was evaluated and was found suitable for the simultaneous determination of propane, 1,1,1-trichloroethane, and petroleum distillates which would be generated into air during the use of fabric protectors.

Fabric protectors. Part II - Propane, 1,1,1-trichloroethane, and petroleum distillates levels in air after application of fabric protectors.

Propane, 1,1,1-trichloroethane, and petroleum distillates levels in air which were generated during the use of aerosol type fabric protectors were monitored by means of the NIOSH charcoal tube, a glass bulb grab sampling, and the GASBADGE passive device techniques. Although 1982 ACGIH TLV-STEL were readily exceeded in an unventilated test room, when fabric was sprayed with 450 g of fabric protector in an unconfined area within a home the generated vapors quickly dispersed and STEL and 8-hour TWA-TLV were not exceeded.

Mutagenicity in a modified Salmonella assay of fabric-protecting products containing 1,1,1-trichloroethane.

Methyl chloroform (1,1,1-trichloroethane) was identified as a major component in two fabric-protector spray products. Mutagenic effects were determined at several dosage levels for the two products and some of the identified components. Levels of organics in the air of sealed desiccators, used as exposure chambers in modified Salmonella reversion assays, were measured by a gas chromatographic technique. Both fabric protectors and two samples of trichloroethane were mutagenic in strain TA 1535 and one of each was mutagenic in strain TA 100. Other constituents, such as petroleum distillate and p-dioxane, were nonmutagenic at the tested exposure levels.