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PubMed1998

On the carcinogenic risk evaluation of diesel exhaust: benzene in airborne particles and alterations of heme metabolism in lymphocytes as markers of exposure.

Diesel exhaust consists of a complex mixture of chemicals which contain known genotoxicants, one of which is benzene. Therefore the concentration of benzene may be used in the evaluation of full external exposure to diesel exhaust. Our attention is focused on the determination of the distribution of benzene between the gas and particulate phases in the breathing zone of bus-garage workers. Bus diesel engine exhaust was the main source of air pollution by benzene and particles. The particulate matter contained benzene in amounts comparable to those usually found for concentrations of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. A much lower concentration of benzene was associated with particulate matter in the winter than in the summer months. The level of benzene in the gas phase showed a dependence on the distance of workplace from the operating diesel motor. The study indicated that benzene associated with diesel exhaust particles (DEP) might be an important factor to consider when studying diesel exhaust exposure from air pollution sources. Since non-genotoxic effects may play an important role in the generation of tumors by genotoxic carcinogens, the level of heme synthesis was proposed as a biomarker of early health effect. Here we present the data on determination of 5-aminolevulinic acid (ALA) synthesis and heme formation in lymphocytes from a group of 45 bus-garage workers and an analogous data from a group of 25 unexposed subjects. The results indicate significant differences in ALA synthesis and heme formation between the exposed workers when compared to the non-exposed individuals. ALA was accumulated and ALA-synthase activity was increased in lymphocytes of garage workers. At the same time ferrochelatase activity was decreased and protoporphyrin contents were elevated. In addition the concentration of porphyrin associated with DNA was significantly increased. Thus, the measurement of some metabolites of heme synthesis in lymphocytes could be a useful biomonitoring index for the determination of a sensitive subgroup of workers who undergo the higher risk of cancer development.

Adult↗

PubMed2003

An unexpected distribution of sodium concentration in serum specimens stored for more than 30 years.

PURPOSE: Sera from over 50,000 pregnant women in the Collaborative Perinatal Project have been frozen at -20 degrees C since 1959 to 1966, and with the health data on their offspring constitute a resource that is still actively used. In two studies using these specimens, we measured sodium concentration to assess desiccation. METHODS: Sodium was measured in over 5,000 specimens by two different methods. For 10 specimens with unusually low sodium values, a substudy was done to investigate the cause. RESULTS: High sodium levels (>140 mmol/L) were present in more than 20% of specimens, and levels were unusually low (<130 mmol/L) in more than 40% of specimens. The substudy showed that filtering the specimens increased sodium levels and that about 14% of the sodium was trapped in particulate matter. CONCLUSIONS: High sodium levels in these specimens were probably due to desiccation and possibly to leaching of sodium from the glass containers. Low sodium levels were probably caused by the particulate matter, which clogged the analytical sampling devices and also trapped sodium. In serum specimens that have been stored for long periods, use of routine laboratory procedures for analysis can yield erroneous results. Furthermore, measured analyte levels can be affected by more than just degradation and desiccation.

Adult↗

PubMed2003

Measurement of attogram quantities of 231Pa in dissolved and particulate fractions of seawater by isotope dilution thermal ionization mass spectroscopy.

A technique has been developed to quantify ultratrace 231Pa (50-2000 ag; 1 ag = 10(-18) g) concentrations in seawater using isotope-dilution thermal ionization mass spectrometry (TIMS). The method is a modification of a process developed by Pickett et al. (Pickett, D. A.; Murrell, M. T.; Williams, R. W. Anal. Chem. 1994, 66, 1044-1049) and extends the technique to very low levels of protactinium. The procedural blank is 16 +/- 15 ag (2sigma), and the ionization efficiency (ions generated/atom loaded) approaches 0.5%. Measurement time is <1 h. The amount of 231Pa needed to produce 231Pa data with an uncertainty of +/-4-12% is 100-1000 ag (approximately 3 x 10(5) to 3 x 10(6) atoms). Replicate measurements made on known standards and seawater samples demonstrate that the analytical precision approximates that expected from counting statistics and that, based on detection limits of 38 and 49 ag, protactinium can be detected in a minimum sample size of surface seawater of approximately 2 L for suspended particulate matter and <0.1 L for filtered (<0.4 microm) seawater, respectively. The concentration of 231Pa (tens of attograms per liter) can be determined with an uncertainty of +/-5-10% (2sigma) for suspended particulate matter filtered from 5 to 10 L of seawater. For the dissolved fraction, 0.5-1 L of seawater yields 231Pa measurements with a precision of 1-10%. Sample size requirements are orders of magnitude less than traditional decay-counting techniques and significantly less than previously reported ICP-MS techniques. Our technique can also be applied to other environmental samples, including cave waters, rivers, and igneous rocks.

Journal Article↗

PubMed2004

Activation of proteases in an anaerobic sulphidogenic bioreactor.

Activities of proteases were stimulated by specific sulphur metabolites during the enhanced hydrolysis of complex polymeric organic carbon in an anaerobic sulphidogenic environment. While sulphate at 1000 mg l(-1) inhibited proteases by 50%, there was a 2.5-fold increase in activity of proteases by added sulphite and a 3.6-fold increase from added sulphide. Two hypothetical models are proposed. First the sulphur species, sulphite (HSO3-) and sulphide (HS-), liberated at different times during the sulphate reduction process, directly activate the proteases, which are associated with the organic particulate matter, leading to a subsequent enhancement of hydrolysis of polymeric material. Second, they indirectly activate the proteases by neutralising the cations on the floc surface disrupting the integrity of the organic particulate floc therebye releasing further entrapped enzymes from the organic particulate matter.

Bacteria, Anaerobic↗

PubMed2002

Filtration efficiency of the ramathibodi nasal filter evaluated by rhinomanometry in high concentration level of laser smoke particle.

Under conditions with a high concentration level of laser smoke particles, the filtration efficiency of the Ramathibodi nasal filter was studied. Different kinds of filter material in the Ramathibodi nasal filter were evaluated in human adults with an anterior standard rhinomanometric method. The Ramathibodi nasal filter with three-layers of a half-face mask filter and a 4 mm thickness polyurethane foam put inside was applied in a simulated human airway. The experiment was conducted in the Otolaryngology Department, Ramathibodi Hospital from October to December 2001. The amount and size of laser smoke particles were measured by a laser diode portable dust monitor. The amount of residual laser smoke particles in the simulated human airway without the Ramathibodi nasal filter of PM2.5, PM10 and PM15 were 100.91 +/- 7.65, 109.10 +/- 7.87 and 120.18 +/- 14.28 mcg/m3 respectively. The amount of residual laser smoke particles in the simulated human airway with the Ramathibodi nasal filter of PM2.5, PM10 and PM15 were 85.55 +/- 3.42, 92.18 +/- 4.40 and 99.72 +/- 5.02 mcg/m3 respectively. The filtration efficacy of the Ramathibodi nasal filter showed a high statistically significant difference with a p-value of <0.001 for three particle sizes. High concentration of laser smoke particles in an operative room represented suspended particulate matters which are very dangerous for human healths. The Ramathibodi nasal filter as a personal respiratory protective device applied in human nasal vestibules could protect the human airway from atmospheric suspended particulate matter.

Adult↗

PubMed1995

[Dust particles and metals in outdoor and indoor air of Upper Silesia].

This work contains the results of the aerosol mass size distribution and preliminary studies on concentrations and size distribution of heavy metals (Pb, Zn, Cu, Mn, Fe and Cd) in indoor and outdoor environment in Upper Silesia (the highly industrialized region in the southern part of Poland). In studies, the measurements of aerosol concentration, mass size distribution, and evaluation of heavy metals concentration were made from December 1992 to April 1994 in some apartments in five towns in Upper Silesia and in one village in the Beskidy Mountains in both indoor and outdoor environments. The particles were fractionated in Andersen cascade impactor. The sampling time was 6-7 days and 4-5 days for indoor and outdoor respectively. Aerosol particulates were collected on A-type glass fiber collection substrate used later for determination of heavy concentrations by atomic absorption spectrophotometry (AAS 3, Carl Zeiss Jena). The dust was mineralized by the means of the mixture of hydrofluoric and nitric acids. The results of mass size distribution as well as the measurements of TSP for indoor and outdoor aerosol show that the main source of particulate matter indoors, in this region, are heavy polluted outdoor air and cigarette smoking. It can be said that, except homes in Knurów and Sosnowiec with hard smokers, the indoor levels of particulate pollution were significant lower than the outdoors levels. Whenever in the indoor environment appear additional source of particulate emission situation can changed. When we compare mass size distribution for outdoor aerosol and indoor aerosol contaminated by tobacco smoke, we can observed considerable increase of indoor aerosol level in the 0.33-0.54 microns size range. Besides, indoor aerosol status may be changed by coal stove emission (displacement of maximum peak to direction of coarse particles). The observed differences in concentration of particulate matter may also indicate the important differences in chemical and physical nature of particles caused by the air filtration and absorption during migration of ambient air into the indoor environment. On the base of comparison of the heavy metals concentrations of fine and coarse fraction and their indoor/outdoor ratio in five selected towns in Upper Silesia it can be said that the level of heavy metals in indoor aerosol is lower than in outdoor (except Pb and Cd) what suggest that migration of ambient air into the homes is a major process which give indoor air contamination of heavy metals.(ABSTRACT TRUNCATED AT 400 WORDS)

Aerosols↗

PubMed1990

Mortality and air pollution in London: a time series analysis.

The relation between air pollution and mortality in London was examined for the winters of 1958-1972. The data exhibited a high degree of autocorrelation, requiring analyses using autoregressive models. There was a highly significant relation between mortality and either particulate matter or sulfur dioxide (after controlling for temperature and humidity), both overall and in each individual year. Graphic analysis revealed a nonlinear relation with no threshold, and a steeper exposure-response curve at lower air pollution levels. In models with both pollutants, particulate matter remained a significant predictor with about a 10% reduction in its estimated coefficients, while sulfur dioxide was insignificant, with a large drop in its estimated coefficient. The authors conclude that particulates are strongly associated with mortality rates in London, and the relation is likely causal.

Air Pollution↗

PubMed2001

Genotoxic effects of carbon black particles, diesel exhaust particles, and urban air particulates and their extracts on a human alveolar epithelial cell line (A549) and a human monocytic cell line (THP-1).

The possible genotoxicity of small particulate matter has been under investigation for the last 10 years. Diesel exhaust particles (DEP) are considered as "probably carcinogenic" (IARC group 2A) and a number of studies show genotoxic effects of urban particulate matter (UPM). Carbon black (CB) is carcinogenic in rats. In this study the cytotoxic and genotoxic potency of these three particle types was investigated by exposing human cells (A549 and THP-1 cell lines) in vitro to CB, DEP (SRM 1650, NIST), and UPM (SRM 1648, NIST) for 48 hr. Cytotoxicity was assessed using the Alamar Blue assay, whereas genotoxicity was assessed using the single-cell gel electrophoresis (comet assay). The particles were characterized with regard to their mean diameter in tissue culture medium (CB 100 nm, DEP 400 nm, UPM 2 microm), their total carbon content (CB 99%, DEP 85%, UPM 15%), and their acid-soluble metal composition (UPM >> CB approximately DEP). The concentrations ranged from 16 ng/ml to 16 microg/ml for cytotoxicity tests and from 16 ng/ml to 1.6 microg/ml for genotoxicity tests. In both assays, paraquat was used as a reference chemical. The CB, DEP, and UPM particles showed no significant cytotoxicity. However, all three particles were able to cause significant DNA damage, although to a different extent in the two cell lines. The genotoxicity of washed particles and dichloromethane extracts was also investigated. In THP-1 cells CB washed particles and DEP extracts caused significant DNA damage. This difference in effect may be related to differences in size, structure, and composition of the particles. These results suggest that CB, DEP, and UPM are able to cause DNA damage and, therefore, may contribute to the causation of lung cancer. More detailed studies on influence of size, structure, and composition of the particles are needed.

Air Pollutants↗

PubMed1988

Ultrasonic wound debridement.

Current management of hand injuries includes debridement by abrasive scrubbing with anti-bacterial detergents, surgical excision, or pressure irrigation. A rat model with a contaminated laceration was used to study the efficacy of ultrasonic debridement to diminish bacterial counts and particulate matter in open wounds. Ultrasonic debridement of hand wounds has several advantages over the current methods of wound debridement. These include a technically simple procedure that is effective in the removal of particulate matter and the reduction of bacterial counts (p less than 0.005). In addition there was no blood loss and no detectable damage of viable tissues as evaluated by electron microscopy. This technique may prove to be a significant advance in the early management of hand wounds.

Animals↗

PubMed1989

[The filter effectiveness of common 15-micron filters (DIN 58362). II: Scanning electron microscopy and roentgen analysis].

When i.v. solutions are used, millions of foreign particles are washed into the organism. Our town studies could recently show that these particles may interact with the organism and thus cause injury. A new method is introduced here (energy dispersive X-ray analysis in scanning electron microscopy, SEM, Jeol 35 CF/EDX, EEDS II Ortec), with which the element combination of foreign particles can be analyzed qualitatively and quantitatively. As a first step an analysis of the particulate matter in filtrates of infusion solutions was carried out in the same way, materials used in infusion therapy (e.g. infusion sets, cannulas, etc.) were analyzed. The results show that most of the particulate matter consists of glass from ampoules, plastic materials from infusion sets and rubber from the rubber stoppers of infusion bottles.

Electron Probe Microanalysis↗

PubMed1996

Exposure to environmental chemicals relevant for respiratory hypersensitivity: global aspects.

Trends of air pollutant concentrations that influence the incidence of respiratory diseases and might be influential for respiratory hypersensitivity are presented and discussed. Data for these trends are collected in UNEP/WHO's Global Environmental Monitoring System GEMS/Air which recently has been revitalized and redirected to become a tool for providing the information necessary for rational air quality management. Data are interpreted with respect to WHO's most recent air quality guidelines, which are an update of the air quality guidelines for Europe published in 1987. A WHO study on the global disease burden and the contribution of air pollution to it is discussed and global estimates of mortality resulting from air pollution through sulphur dioxide and suspended particulate matter, by different economic regions, are given. Starting from the air quality guidelines still valid at the time of publication of the update, about 460,000 excess deaths globally are due to suspended particulate matter and about 370,000 to sulphur dioxide.

Air Pollutants↗

PubMedDate not supplied

Flexible modeling of exposure-response relationship between long-term average levels of particulate air pollution and mortality in the American Cancer Society study.

Accurate estimation of the exposure-response relationship between environmental particulate air pollution and mortality is important from both an etiologic and regulatory perspective. However, little is known about the actual shapes of these exposure-response curves. The objective of this study was to estimate the exposure-response relationships between mortality and long-term average city-specific levels of sulfates and fine particulate matter (PM(2.5)). We reanalyzed the data derived from the American Cancer Society (ACS) Cancer Prevention Study II, a large prospective study conducted in the United States between 1982 and 1989. Exposure to particulate air pollution was assessed prior to entry into the cohort. Mean sulfate concentrations for 1980 were available in 151 cities, and median PM(2.5) levels between 1979 and 1983 were available in 50 cities. Two sampling strategies were employed to reduce the computational burden. The modified case-cohort approach combined a random subcohort of 1200 individuals with an additional 1300 cases (i.e., deaths). The second strategy involved pooling the results of separate analyses of 10 disjoint random subsets, each with about 2200 participants. To assess the independent effect of the particulate levels on all-causes mortality, we relied on flexible, nonparametric survival analytical methods. To eliminate potentially restrictive assumptions underlying the conventional models, we employed a flexible regression spline generalization of the Cox proportional-hazards (PH) model. The regression spline method allowed us to model simultaneously the time-dependent changes in the effect of particulate matter on the hazard and a possibly nonlinear exposure-response relationship. The PH and linearity hypotheses were tested using likelihood ratio tests. In all analyses, we stratified by age and 5-yr age groups and adjusted for the subject's age, lifetime smoking exposure, obesity, and education. For both fine particles (PM(2.5)) and sulfates, there was a statistically significant (at.05 level) departure from the conventional linearity assumption. The adjusted effect of fine particles on mortality indicated a stronger relationship in the lower (up to about 16 microg/m(3)) than in the higher range of their values. Increasing levels of sulfates in the lower range (up to about 12 microg/m(3)) had little impact on mortality, suggesting a possible "no-effect threshold." For body mass index (BMI), the risks were lowest in the middle range and increased for both very obese and very lean individuals. It was concluded that flexible modeling yields new insights about the effect of long-term air pollution on mortality.

Air Pollutants↗

PubMed2006

Mercury emission from crematoria.

The purpose of this study, undertaken at a cremator representing an example of current equipment and cremation practices in use in Italy, is to assess the possible mercury emitted during cremation and substantiate the current data available. This paper reports some preliminary results concerning mercury and total particulate matter emissions during three cremation processes. The obtained results gave a mercury concentration ranging from 0.005 to 0.300 mg/m3 and a mercury emission factor ranging from 0.036 to 2.140 g/corpse cremated. The total particulate matter concentration range was 1.0 to 2.4 mg/m3.

Environmental Pollutants↗

PubMed1989

Potential adverse health effects of wood smoke.

The use of wood stoves has increased greatly in the past decade, causing concern in many communities about the health effects of wood smoke. Wood smoke is known to contain such compounds as carbon monoxide, nitrogen oxides, sulfur oxides, aldehydes, polycyclic aromatic hydrocarbons, and fine respirable particulate matter. All of these have been shown to cause deleterious physiologic responses in laboratory studies in humans. Some compounds found in wood smoke--benzo[a]pyrene and formaldehyde--are possible human carcinogens. Fine particulate matter has been associated with decreased pulmonary function in children and with increased chronic lung disease in Nepal, where exposure to very high amounts of wood smoke occurs in residences. Wood smoke fumes, taken from both outdoor and indoor samples, have shown mutagenic activity in short-term bioassay tests. Because of the potential health effects of wood smoke, exposure to this source of air pollution should be minimal.

Humans↗

PubMed2002

Contribution of a medium-sized tropical river to the particulate heavy-metal load for the South Atlantic Ocean.

The Paraíba do Sul River is a medium-sized river, 1145 km in length with a drainage basin of 55,400 km2. The riverine fluxes of particulate metals (Cu, Cr, Zn, Mn and Fe) were investigated over 24 months. Particulate matter samples were monthly collected from April 1994 to March 1996. The first 12-month period presented lower rainfall than the second, although both periods presented average precipitation lower than the regional average. The particulate matter flux in the second period (2,042,080 t) was 250% higher than the first period (821,489 t). The same trend was observed for the associated metals, which presented higher fluxes in the second period. This study highlights the strong dependence of the transported mass on the rainfall, and consequently with the river water discharge. The Paraiba do Sul River presents a low contribution to the world oceans, although the local contribution could be considered relevant.

Journal Article↗

PubMed1990

Fragmentation and ruminal escape of particles as related to variations in voluntary intake, chewing behavior and extent of digestion of potentially digestible NDF in heifers.

The distribution of particles of differing sizes in ruminal, duodenal and fecal samples, the efficiency of particle breakdown and ruminal escape and their relationships to voluntary intake, chewing behavior and extent of digestion of potentially digestible NDF were examined in six heifers (290 kg average BW) with ruminal, duodenal and ileal cannulas. Animals had ad libitum access to corn silage, with or without 100 mg monensin head-1.d-1, in a two-period crossover design. Variations in voluntary intake by individual animals were positively related to size of digesta particles (median retaining aperture, MRA) in the dorsal rumen (P = .07) and rectum (P = .08), but not to MRA of particulate matter from the ventral rumen and duodenum. No significant relationships existed among eating or ruminating activities and distribution of particles of differing sizes in digesta from any of the digestive sites. The MRA of particulate matter in duodenal and rectal digesta were negatively related (P = .08 and P = .10) to extent of digestion of potentially digestible NDF (PDNDF) at these sites. Voluntary intake was related positively to efficiency of ruminative degradation of digesta particles appearing at the duodenum (P = .09) and to duodenal DM digesta flow per opening of the reticulo-omasal orifice (ROO; P = .02), the latter being negatively related to extent of digestion of PDNDF in duodenal digesta (P = .09). These results suggest that animals with higher intake capability are more efficient ruminators and can partially override constraining factors of particle size and byoyancy and thereby achieve a larger amount of DM flowing per opening of the ROO.

Animal Feed↗

PubMed2006

Analysis of primary fine particle national ambient air quality standard metrics.

In accordance with the Clean Air Act, the U.S. Environmental Protection Agency (EPA) is currently reviewing its National Ambient Air Quality Standards for particulate matter, which are required to provide an adequate margin of safety to populations, including susceptible subgroups. Based on the latest scientific, health, and technical information about particle pollution, EPA staff recommends establishing more protective health-based fine particle standards. Since the last standards review, epidemiologic studies have continued to find associations between short-term and long-term exposure to particulate matter and cardiopulmonary morbidity and mortality at current pollution levels. This study analyzed the spatial and temporal variability of fine particulate (PM2.5) monitoring data for the Northeast and the continental United States to assess the protectiveness of various levels, forms, and combinations of 24-hr and annual health-based standards currently recommended by EPA staff and the Clean Air Scientific Advisory Committee. Recommended standards have the potential for modest or substantial increases in protection in the Northeast, ranging from an additional 13-83% of the population of the region who are living in areas not likely to meet new standards and thereby benefiting from compliance with more protective air pollution controls. Within recommended standard ranges, an optimal 24-hr (98th percentile)/annual standard suite occurs at 30/12 microg/m3, providing short- and long-term health protection for a substantial percentage of both Northeast (84%) and U.S. (78%) populations. In addition, the Northeast region will not benefit as widely as the nation as a whole if less stringent standards are selected. Should the 24-hr (98th percentile) standard be set at 35 microg/m3, Northeast and U.S. populations will receive 16-48% and 7-17% less protection than a 30 microg/m3 standard, respectively, depending on the level of the annual standard. A 30/12 microg/m3 standard suite also provides nearly equivalent 24-hr and annual control of PM2.5 distributions across the United States, thereby ensuring a more uniform and consistent level of protection than unmatched or "controlling" and "backstop" standards. This could occur even within EPA staff's recommended range of standard suites, where 22-43% of the monitors in the country could meet a controlling standard but fail to meet the combined backstop standard, resulting in inconsistent short- and long-term protection across the country. An equivalent standards combination of 30/12 microg/m3 would minimize the wide variation of protectiveness of 24-hr and annual PM2.5 concentrations. Furthermore, given recent associations of subdaily exposures and acute adverse health effects, in the absence of a subdaily averaging metric, a stringent 24-hr standard will more effectively control maximum hourly and multihourly peak concentrations than a weaker standard.

Air Pollutants↗

PubMed1980

[Passive smoking in the work place].

The air pollution due to tobacco smoke and its effects on employees were investigated in 44 work-rooms. For that purpose the concentration of CO, NO, Nicotine and the Particulate Matter were determined and 472 employees were interviewed about annoyance and irritations. The mean values of the concentrations of the components due to tobacco smoke are: CO = 1.1 ppm, NO = 32 ppb, Nicotine = 0.9 micrograms/m3, Particulate Matter = 133 micrograms/m3. The use of an indicator is discussed. One third of the employees qualifies the air wit regard to smoke at work place as bad. 40% of the interviewed persons are disturbed by smoke. One quarter of th persons indicates eye irritations. The majority of the employees support a separation of the rooms in smoking and non-smoking areas. This seems to be the most appropriate preventive measure for the protection of the nonsmokers at work.

Adult↗