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At least 991 records · Page 55Linked to original sources
PubMed1983

Bioassay of extracts of ambient particulate matter.

Organic extracts from airborne particles collected at various sites in Scandinavia have been tested for mutagenicity in the Ames Salmonella/microsome assay. Extracts from particles in the respirable size fraction (diameter less than 3 microns) were mutagenic with and without metabolic activation. The mutagenic activity varied from day to day, mainly due to variations in meteorological parameters, especially wind speed and atmospheric stability. A seasonal variation could also be observed, with the highest average values in winter time. Samples collected in urban areas were considerably more mutagenic than samples from background areas. The results suggest that exhaust from motor vehicles are the most important source of mutagenic particles in urban areas. Comparison of roof top samples with street level samples indicated that atmospheric reactions cause transformation of nonpolar compounds in the primary emission to more oxygenated mutagenic compounds. It is, however, not known to which degree this causes an overall increase of the mutagenic activity. The mutagenic activity of emissions from stationary combustion sources have also been studied, and residential heating by burning solid fuels in small combustion units have been shown to be a major contributor to mutagens in the environment.

Air Pollutants↗
PubMed1988

A model for the formation of airborne particulate matter based on the gas-phase adsorption on amorphous carbon blacks.

This paper reports the physicochemical properties that describe the adsorption of a series of solutes onto the surfaces of amorphous carbon blacks. Adsorption was studied at concentrations that correspond to low surface coverages and in the presence of volatile solvent diluents. The adsorbates and adsorbents were selected for their relevance as models for environmental agent-particle complexes originating from incomplete combustion. The data clearly show that the major factors that determine the strength of adsorption are the surface properties of the adsorbent and the intermolecular forces between the surface and the adsorbing molecule. The heat of adsorption data have been used to predict the lifetime of the absorbate-adsorbent complexes.

Adsorption↗
PubMed1996

In vitro characterization of DNA adducts formed by foundry air particulate matter.

This study is part of an ongoing investigation of biomarkers in iron foundry workers exposed to polycyclic aromatic compounds. Foundry workers with the highest exposures had elevated levels of DNA adducts in their white blood cells in previous studies. The purpose of this study was to characterize the nature of DNA reactive chemicals in foundry air samples through incubating the foundry filter extract with DNA and activation enzymes. Calf thymus DNA was incubated with foundry filter extract and activated by either rat liver activation mixture (S9 mix) or xanthine oxidase. A complex pattern of adducts was observed on thin-layer chromatography (TLC) by the 32P-postlabeling assay. Two selected polycyclic aromatic hydrocarbons (PAHs)--1-NP-and anti(+/-)benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide [anti(+/-) BPDE]-DNA adducts--were used as marker compounds in characterizing the postlabeled DNA adducts by TLC combined with high-performance liquid chromatography (HPLC). After an initial separation of DNA adducts by TLC, individual spots were isolated and separated further on HPLC. HPLC analysis and spiking with anti(+/-)BPDE-DNA standard confirmed the co-migration of the anti(+/-)BPDE-DNA standard with one PAH adduct formed by the S9 mix-activated DCM extract in calf thymus DNA.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed2003

Determination of the extraction efficiency of polycyclic aromatic hydrocarbons from airborne particulate matter.

Polycyclic aromatic hydrocarbons are common environmental pollutants that reach atmosphere in the form of aerosol adsorbed on soot, ash and dust. Having in mind its carcinogenic and mutagenic effects most countries have regulations concerning their estimation in environmental samples. In this work we have investigated extraction efficiency of several polycyclic aromatic hydrocarbons from flying particles collected on glass fiber filters. Efficiency of extraction of different duration in Soxhlet apparatus, ultrasonic bath and boiling toluene under reflux were compared. It has been established that compounds having two or three condensed rings are lost during evaporation of toluene that was used as a solvent. For compounds having five or more condensed rings extraction in ultrasonic bath and boiling toluene using magnetic stirrer and reflux are the most efficient.

Journal Article↗
PubMed2004

Effect of simulated ambient particulate matter exposure on performance, rectal temperature, and leukocytosis of young Spanish goats with or without tilmicosin phosphate.

Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo) were randomly assigned to simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.

Animals↗
PubMed1985

Counting mammalian spermatozoa in biological fluids containing particulate matter.

Accurate counting of spermatozoa in biological fluids by particle counters requires elimination of competing background. This was accomplished by dissolving cell organelles and other lipid and proteinaceous material with sodium dodecyl sulfate to leave the sperm nucleus. Progress of selective dissolution of interfering background versus sperm nuclei was monitored by phase contrast microscopy. Rabbit semen was diluted in 2.5% sodium dodecyl sulfate (wt/vol) and then 1:1 (vol/vol) with .5 M sodium hydroxide. Suspensions were incubated, diluted 1:200 in .1 M sodium citrate-.1% Triton-X, and counted after 5, 10, and 20 min with a Coulter Counter. All treatment times resulted in similar mean counts, ranging from 367 to 369 X 10(6) sperm/ml. These means were slightly higher than the 350 X 10(6) sperm/ml for hemocytometer counts, but the correlation with hemocytometer counts was r greater than or equal to .98. Bull semen was diluted in either 1) citrate-Triton-X, 2) .25 M Tris-20% egg yolk, or 3) heated whole milk and further treated with 10% sodium dodecyl sulfate and .5 M sodium hydroxide. After 15 min, treated samples were diluted 1:200 in citrate-Triton-X and counted. Following treatment, estimated sperm concentration in the three diluents was not different from that of untreated sperm in citrate-Triton-X. The procedure was successfully applied to bull sperm diluted in milk and packaged in .5-ml French straws used routinely for artificial insemination.

Animals↗
PubMed1983

Trace element analysis of airborne particulate matters in relation to air pollution in Benin City, Nigeria.

The methods of neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) have been employed to determine the concentration levels of 18 trace elements in filter-collected airborne aerosols over an urban area in Nigeria. The highest concentrations measured in the samples were for Cl, Na, Al, Pb, Ca and Zn. The aerosol particles were found to contain higher concentrations of soil-derived trace elements, such as Al, Ti, K and Na than those derived from combustion and industrial activities such as As, Cd, Mn, Zn, Pb, Ni and Sb. The average precision of measurements varied between +/- 5.2% and 13% for most elements. Possible sources of the elements are also discussed.

Aerosols↗
PubMed1996

Potential toxicity of retrograde uterine passage of particulate matter.

Dusting powders are commonly used on surgical gloves, examination gloves, and condoms. In addition, they are used in diaphragms, sanitary napkins, and toiletries. These dusting powders can gain access to the abdominal cavity through the vagina or through surgical intervention. The toxicity of these dusting powders in the abdominal cavity can be divided into acute and chronic complications that may be life-threatening. The use of medical and surgical products without dusting powders is strongly recommended.

Condoms↗