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Generation and characterisation of diesel exhaust in a facility for controlled human exposures

2010-07-27

An idling medium-duty diesel truck operated on ultralow sulphur diesel fuel was used as an emission source to generate diesel exhaust for controlled human exposure. Repeat tests were conducted on the Federal Test Procedure using a chassis dynamometer to demonstrate the reproducibility of this vehicle as a source of diesel emissions. Exhaust was supplied to a specially constructed exposure chamber at a target concentration of 100 íg á m-3 diesel particulate matter (DPM). Spatial variability within the chamber was negligible, whereas emission concentrations were stable, reproducible, and similar to concentrations observed on the dynamometer. Measurements of nitric oxide, nitrogen dioxide, carbon monoxide, particulate matter (PM), elemental and organic carbon, carbonyls, trace elements, and polycyclic aromatic hydrocarbons were made during exposures of both healthy and asthmatic volunteers to DPM and control conditions. The effect of the so-called “personal cloud” on total PM mass concentrations was also observed and accounted for. Conventional lung function tests in 11 volunteer subjects (7 stable asthmatic) did not demonstrate a significant change after 2-h exposures to diesel exhaust. The authors concluded that the findings from this study demonstrate that this facility can be effectively and safely used to evaluate acute responses to diesel exhaust exposure in human volunteers.

Authors: Sawant AA, Cocker DR 3rd, Miller JW, Taliaferro T, Diaz-Sanchez D, Linn WS, Clark KW, Gong H Jr.

Full Source: Journal of Air & Waste Management, 58 (6), 829-837, Eng
Personal child and mother carbon monoxide exposures and kitchen levels: Methods and results from a randomised trial of wood fired chimney cookstoves in Guatemala (RESPIRE)

2010-07-27

During the first randomised intervention trial (RESPIRE: Randomised Exposure Study of Pollution Indoors and Respiratory Effects) in air pollution epidemiology, the authors pioneered application of passive carbon monoxide (CO) diffusion tubes to measure long-term personal exposures to wood smoke. This literature reports the protocols and validations of the method, trends in personal exposure for mothers and their young children, and the efficacy of the introduced improved chimney stove in reducing personal exposures and kitchen concentrations. Passive diffusion tubes originally developed for industrial hygiene applications were deployed on a quarterly basis to measure 48-h integrated personal carbon monoxide exposures among 515 children 0-18 months of age and 532 mothers aged 15-55 years and area samples in a subsample of 77 kitchens, in households randomised into control and intervention groups. Instrument comparisons among types of passive diffusion tubes and against a continuous electrochemical CO monitor indicated that tubes responded nonlinearly to CO, and regression calibration was used to reduce this bias. Before stove introduction, the baseline arithmetic (geometric) mean 48-h child (n)270), mother (n)529) and kitchen (n)65) levels were, respectively, 3.4 (2.8), 3.4 (2.8) and 10.2 (8.4) p.p.m. The between-group analysis of the 3355 post-baseline measurements found CO levels to be significantly lower among the intervention group during the trial period: kitchen levels: -90%; mothers: -61%; and children: -52% in geometric means. No significant deterioration in stove effect was observed over the 18 months of surveillance. The reliability of these findings is strengthened by the large sample size made feasible by these unobtrusive and inexpensive tubes, measurement error reduction through instrument calibration, and a randomised, longitudinal study design. The authors concluded that the findings from the first randomised trial of improved household energy technology in a developing country demonstrated that a simple chimney stove can substantially reduce chronic exposures to harmful indoor air pollutants among women and infants.

Authors: Smith, Kirk R.; Mccracken, John P.; Thompson, Lisa; Edwards, Rufus; Shields, Kyra N.; Canuz, Eduardo; Bruce, Nigel

Full Source: Journal of Exposure Science & Environmental Epidemiology 2010, 20(5), 406-416 (English)
Mineral analysis of human hair in the assessment of bioavailability of nutritive and toxic elements of industrial origin from food

2010-07-27

In this study, inductively coupled plasma optical emission spectrometry was used for the detection of 25 major and trace element concentrations in scalp hair samples from a population of 159 students and employees of Wroclaw University of Technology. The effect of frequency of egg consumption and drinking milk, type of consumed eggs and bread buttering, the consumption of cottage and mould cheese, the source of fruits and vegetables, degree of food processing and the consumption of meals at the academic cafeteria on the mineral content of hair was analysed. The results were elaborated statistically.

Authors: Chojnacka, Katarzyna; Zielinska, Agnieszka; Michalak, Izabela; Gorecka, Helena; Mikulewicz, Marcin; Gorecki, Henryk

Full Source: Przemysl Chemiczny 2010, 89(4), 342-347 (Polish)
Review on the effects of exposure to spilled oils on human health

2010-07-27

Harmful effects of oil spills on diverse flora and fauna species have been extensively studied. Nevertheless, only a few studies have been compiled in the literature dealing with the repercussions of oil exposure on human health; most of them have focused on acute effects and psychological symptoms. In this study, the authors gathered all these studies and analysed the possible consequences of this kind of complex exposure in the different aspects of human health. Studies found on this topic were related to the disasters of the Exxon Valdez, Braer, Sea Empress, Nakhodka, Erika, Prestige, and Tasman Spirit oil tankers. The majority of them were cross-sectional; many did not include control groups. Acute effects were evaluated taking into account vegetative-nervous symptoms, skin and mucous irritations, and also psychological effects. Genotoxic damage and endocrine alterations were assessed only in individuals exposed to oil from Prestige. The authors concluded that the results of the reviewed articles clearly support the need for biomonitoring human populations exposed to spilled oils, especially those individuals involved in the cleanup, in order to evaluate not only the possible immediate consequences for their health but also the medium- and long-term effects, and the effectiveness of the protective devices used.

Authors: Aguilera, Francisco; Mendez, Josefina; Pasaro, Eduardo; Laffon, Blanca

Full Source: Journal of Applied Toxicology 2010, 30(4), 291-301 (Eng)
SAFETY

Kinetic simulation of gas explosion and inhibition mechanism in enclosed space

2010-07-29

Through amending the SENKIN code of CHEMKIN III chemical kinetics package, the computational model of gas explosion in a constant volume bomb was built, and the detailed reaction mechanisms (including 53 species, 325 reactions) were adopted. The trends of variation of the mole fractions of reactants, activation centres in the explosion process, and the mole fractions of catastrophic gases after explosion were analysed by using this model. Furthermore, through the sensitivity analysis of the reaction mechanisms of gas explosion, the key reactions that affected gas explosion and formation of catastrophic gases were identified. At the same time, the inhibition mechanism of water on gas explosion and formation of catastrophic gases were analysed. The results showed that the temperature and pressure were 2700 K° and 0.22 MPa respectively, after gas explosion when the mixed gas had no water. When the mole fraction of water in the mixed gas was 10%, the temperature and pressure were 2580 K° and 0.21 MPa respectively. When the mole fraction of water in the mixed gas was 15%, the temperature and pressure decreased by 180 K° and 0.025 MPa respectively, against the case that the mixed gas had no water. Furthermore, the water in the mixed gas would inhibit gas explosion and the formations of CO, CO2 and NO2.

Authors: Liang, Yuntao; Zeng, Wen.

Full Source: Huagong Xuebao (Chinese Edition) 2009, 60(7), 1700-1706 (China).
Safety management of nanoparticle materials in university labs

2010-07-29

The development of nanotechnology leads to substantive changes in various fields, which dramatically improves the effectiveness of new materials. However, as the products are used in human life, unexpected behaviour of toxicology is reported successively. Nanoparticle materials have a lot of special physicochemical properties compared with conventional materials, which can result in some special biological effects for their small size. This paper discussed how to dispose and manage nanoparticles in labs before their physicochemical properties and their toxicology and bioactive mechanisms were completely comprehended.

Authors: Zhou, Gu; Li, Song.

Full Source: Shiyanshi Yanjiu Yu Tansuo 2009, 28(4), 160-162, 171 (China).
Nanoparticles can be safely handled

2010-07-29

The Nanocare project of the chemical industry is carried out together with academic institutions including the aggregation and agglomeration behaviour of nanoparticles and the stability of these structures. In addition the project is compared, available methods for the detection of airborne particles and aerosols by intentionally modified materials, which serve as a reference. Moreover, the industry is involved in projects with similar objectives (Nanosafe II, Nanoderm, tracer). The International Standardization Organisation (ISO) and the German Institute for Standardisation (DIN) initialises parallel occupational measurement techniques, including sampling and treatment, monitoring, reference materials, progressing.

Author: Jopp, Klaus

Full Source: LaborPraxis 2009, 33(12), 20-21 (Germany).