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At least 487 records · Page 27Linked to original sources
PubMed1994

Combined chemical, physical hazards make exposures harder to calculate. Studies show multiple exposures must be evaluated wholly rather than 'adding up' individual risks.

Clearly, current research adds to the mounting scientific evidence that combined exposures can produce greater toxicity than would be predicted using an additive model. Although there is not yet a quantitative method to determine the risks associated with multiple exposures, safety and health specialists must begin to consider the health effects from the entire work process, rather than individual chemical or physical agents. Moreover, organizations involved in risk assessment and standard-setting must evaluate the interactive effects of combined chemical and physical agent exposures. This will make personnel exposure standards comprehensive in addressing realistic occupational health risks.

Animals↗
PubMed2006

Non-ionising radiation human exposure assessment near telecommunication devices in Croatia.

This paper gives an overview of the regulatory acts in non-ionising radiation in the world, with a special emphasis on basic guidelines issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). ICNIRP Guidelines are implemented in many countries worldwide. Croatia has also implemented them indirectly through the European Recommendation 1999/519/EC. The Croatian regulatory acts include the Non-lonising Radiation Protection Act, Ordinance on Electromagnetic Fields (EMF) Protection, and the Ordinance on Basic Requirements for Devices which produce Optical Radiation and Measures for Optical Radiation Protection. Dosimetry and densitometry are compliant with relevant international and European standards. The paper presents an example of densitometric human exposure assessment in complex indoor exposure conditions. In spite of a high number of indoor and outdoor sources and the "worst-case exposure assessment", the results are within the limits defined by the Croatian EMF Ordinance.

Electromagnetic Fields↗
PubMed1991

Non-linear dependence of the dielectric properties of chick embryo myoblast membranes exposed to a sinusoidal 50 Hz magnetic field.

Primary chick embryo myoblasts can be a useful tool for studying the developmental events which accompany myoblast differentiation, particularly myoblast membrane fusion. To determine whether the electrical properties and/or fusion in these systems are affected by 50 Hz magnetic fields, chick embryo myoblast cultures were exposed to B-field intensities ranging from 1 to 10 mT. The electrical parameters of the myoblasts, i.e. membrane conductivity, membrane permittivity and the conductivity of the cell interior (cytosol) were determined by the analysis of conductivity dispersion data in the radio frequency range (10 kHz-100 MHz). Preliminary results indicate that the time of fusion (60 h) is not affected by these fields, but that the absolute values of the two membrane electrical parameters are affected. In particular, a B-field intensity-dependent decrease was observed. The maximum effect resulted after a 1 h exposure to a magnetic flux density of about 5 mT. The conductivity of the cytosol remained unchanged. These data seem to indicate that exposure to 50 Hz magnetic fields affects both static and dynamic membrane properties in primary chick embryo myoblasts.

Animals↗
PubMedDate not supplied

Health risks of exposure to non-ionizing radiation--myths or science-based evidence.

INTRODUCTION: The non-ionizing radiation (NIR) contains large range of wavelengths and frequencies from vacuum ultraviolet (UV) radiation to static electric and magnetic fields. Biological effects of electromagnetic (EM) radiation depend greatly on wavelength and other physical parameters. OPTICAL RADIATION: The Sun is the most significant source of environmental UV exposure, so that outdoor workers are at risk of chronic over-exposure. Also exposure to short-wave visible light is associated with the aging and degeneration of the retina. Especially hazardous are laser beams focused to a small spot at the retina, resulting in permanent visual impairment. ELECTROMAGNETIC FIELDS: Exposure to EM fields induces body currents and energy absorption in tissues, depending on frequencies and coupling mechanisms. Thermal effects caused by temperature rise are basically understood, whereas the challenge is to understand the suspected non-thermal effects. Radiofrequency (RF) fields around frequencies of 900 MHz and 1800 MHz are of special interest because of the rapid advances in the telecommunication technology. The field levels of these sources are so low that temperature rise is unlikely to explain possible health effects. Other mechanisms of interaction have been proposed, but biological experiments have failed to confirm their existence.

Electromagnetic Fields↗
PubMedDate not supplied

Risks of occupational exposure to optical radiation.

During the past 40 years a wide body of biomedical research has been conducted to understand the factors which influence injury to optical radiation-particularly with respect to the eye. A primary motivation for much of this research has been the advent of lasers, since focal damage of the retina from a collimated beam exposure is possible at some distance. A wide range of research studies provided the basis for establishing human exposure limits for ultraviolet and infrared radiation as well as for intense visible light. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has published guidelines for human exposure, and these are available at no cost from the ICNIRP website (http://www. icnirp.org). Laser Maximum Permissible Exposure (MPE) limits used in international safety standards, such as those of the International Electrotechnical Commission (IEC) are based upon ICNIRP guidelines. Practical laser safety standards and regulations have evolved to promote the safe design and use of laser products. As a result of newer laser applications and increased knowledge of the biological effects, MPEs have been revised a number of times. Despite the existence of safety standards and regulations, accidental eye injuries from lasers still occur. Accidental exposure to welding arcs and intense lights occur more fequently, but the consequential loss of vision is much less, with permanent effects rare. Accidental human exposure information also adds to our understanding of ultraviolet, blue-light and laser induced retinal injury. Accidents are most frequently attributed to the lack of understanding of hazards and a failure to follow established safe work practices.

Eye Injuries↗
PubMed1991

[Examples of intervention in cases of electromagnetic pollution in research laboratories].

Two examples of technical measures taken to reduce levels of radiofrequency electromagnetic radiation in research laboratories are reported. The first intervention was aimed at avoiding undue exposure of operators. The case is of interest because of the special exposure conditions, which are not as well characterized as in industrial applications, and require ad hoc analyses, measurements, and mitigation actions. As shown by the second example, such actions also allow effective screening of experimental apparatuses, which is of special importance when high sensitivities are required.

Equipment Design↗
PubMed1991

Effects of modulated and continuous microwave irradiation on the morphology and cell surface negative charge of 3T3 fibroblasts.

Mouse embryo 3T3 cells were irradiated with 2450 MHz continuous and low frequency (16 Hz) square modulated waves of absorbed energy ranging from 0.0024 to 2.4 mW/g. The low frequency modulated microwave irradiation yielded more morphological cell changes than did the continuous microwave fields of the same intensity. The amount of free negative charges (cationized ferritin binding) on cell surfaces decreased following irradiation by modulated waves but remained unchanged under the effect of a continuous field of the same dose. Modulated waves of 0.024 mW/g dose increased the ruffling activity of the cells, and caused ultrastructural alteration in the cytoplasm. Similar effects were experienced by continuous waves at higher (0.24 and 2.4 mW/g) doses.

3T3 Cells↗