Indoor and Built Environment

Expansion of the use of mobile phones increases con cern about any eventual health risks from the micro waves they emit. ln this work, we have looked at whether these microwaves could disturb the nervous system, the auditory system or the endocrine system. No significant effect was observed in the responses of the auditory brainstem or the endocrine system, but a slight increase in activity was observed on the Q-EEG. The functional significance of this effect remains to be evaluated, as well as any possible health impact.

The effects of continuous exposure of chick embryos and young chickens to the electromagnetic fields (EMFs) emitted by video display units (VDUs) and GSM cell phone radiation, either the whole spectrum emitted or attenuated by a copper gauze, were investigated. Perma nent exposure to the EMFs radiated by a VDU was asso ciated with significantly increased fetal loss (47-68%) and markedly depressed levels of circulating specific antibodies (lgG), corticosterone and melatonin. We have also shown that under chronic exposure conditions, GSM cell phone radiation was harmful to chick embryos, stressful for healthy mice and, in this species, synergistic with cancer insofar as it depleted stress hormones. The same pathological results were observed after substan tial reduction of the microwaves radiated from the cell phone by attenuating them with a copper gauze.

Since electricity is used everywhere, exposure to electro magnetic fields of extremely low frequency (50-60 Hz) is unavoidable in our daily life. The question of whether these electromagnetic fields could possibly have any bio logical or health effects has been a major environmental issue for more than 20 years. At high field strengths, bio logical effects such as nerve and cardio-stimulation through the induction of currents in the body have been noted. These biological effects have been used in the drafting of standards for public and professional expo sure. However, it is the search for effects at low field lev els that has been the focus of much research. The main results of this research can be summarised as follows: in vivo studies on whole animals have shown that there is no convincing evidence that electromagnetic fields cause cancer or birth defects, and despite some reduction in pineal and blood melatonin in rodents, studies on lambs, baboons and humans do not support such an effect of electromagnetic fields, while in vitro studies have shown that exposure to electromagnetic fields at usual residen tial levels (<100 μT) does not produce any significant in vitro effects that could be replicated in independent stud ies. These results, correlated with the data provided by more recent epidemiological studies, do not show that exposure to electromagnetic fields at the usual residen tial exposure levels presents a human health hazard.

Various living organisms, human workers and children were tested for any biological action resulting from exposure to radiation from video display terminals (VDTs). VDTs were powered by a 50-Hz alternating volt age of 220 V. Measured electric and magnetic fields were 13 V/M and 50 nT, respectively. Living organisms were maintained under their normal breeding conditions and control values were obtained before switching on the VDT. Various effects related to the irradiation time were demonstrated, i.e. growth delay in algae and Drosophila, a body weight deficiency in rats, abnormal peaks of mor tality in Daphnia and Drosophila, teratological effects in chick embryos and behavioural disturbances in rats. The embryonic and neonatal periods showed a high sensitiv ity to the VDT radiation. In humans, after 4 h of working in front of a VDT screen, an increase in tiredness and a decrease in the resistance of the immune system were observed in workers. In prepubertal children, 20 min of exposure were sufficient to induce neuropsychological disturbances; pre-pubertal young people appear to be particularly sensitive to the effect of the radiation. ln human testicular biopsies cultured in vitro for 24 h in front of a VDT screen, mitotic and meiotic disturbances, the appearance of degeneration in some aspects of the cells and significant disorganisation of the seminiferous tubules were demonstrated and related to modification of the metabolism of the sample. An experimental appa ratus has been developed and tested that aims to pre vent the harm from VDT radiation. Known commercially as the emf-Bioshield®, it ensures effective protection against harmful biological effects of VDT radiation.

Solar radiation, including its ultraviolet (UV) compo nents, is a key factor in life on earth. While small quanti ties of UV are beneficial for people (for example, through the production of vitamin D), the considerable amount to which people sometimes expose themselves may have extremely noxious effects including actinic erythema, sunburn, photo-induced diseases, photo-worsened dis eases, actinic ageing and skin cancers. Since the last cen tury, human exposure to UV has increased either by social-behaviour modifications, or by anthropogenic dis ruption to the environment through, among other things, industrial development. The World Health Organisa tion's (WHO) INTERSUN programme has several com ponents: action for reconstruction of the ozone layer through, for example, preventing dumping of chloro fluorocarbons; creation and popularisation of a global UV Index; prevention campaigns underlining the risks from UV exposure including dissemination of informa tion to daily newspapers. These are all aimed at reducing the amount of UV radiation that people receive. In addi tion the WHO advises against exposure to UV artificial sources to reduce overall the quantity of UV received.

The aim of this project was to assess the risk due to inha lation of radon and its decay products using a horizontal approach across a large-scale research programme. The central objective was the assessment of human risk, a task that required a combination of several programmes and involved a multidisciplinary approach. Five main topics were addressed: radioactive aerosol studies, mod elling, human studies, animal studies and retrospective assessment of radon exposure. The five studies were distributed between working groups. The rationale of this project was to pool the expertise from laboratories working in different fields of radiation protection. This paper summarises the main achievements made through this multidisciplinary research programme and the synergies that occurred between the different groups.

Radon is a radioactive gas of natural origin that tends to accumulate in buildings. Although the levels recorded can be reduced, this requires the co-operation of resi dents, and the French population has a very poor under standing of radon-induced risk. The justification for keep ing a close watch on indoor radon concentrations is the underlying risk of lung cancer as a consequence of expo sure to high levels. Two official statements dealing with radon risk management were issued in 1999 in France to define the thresholds that should not be exceeded. The results of measurement campaigns, the number of build ings where concentrations above these thresholds are likely to occur, the identification of high-radon potential areas and the actions taken locally together with the way that the risk from radon and remedial actions are per ceived are reviewed herein.

People are exposed to several types of ionising radiation from both natural and man-made sources. A set of con cepts and dosimetric quantities, along with approxima tions or models, may be used to evaluate doses from these radiation sources whatever they are and whatever their form or the energy and the intensity of their radia tion. This scheme is considered to provide reliable re sults for the purposes of protection against radiation. However, some limitations are also illustrated which account for the various and complex mechanisms which intervene in the real situation of exposure to radiation.

Now is an appropriate time to elaborate on an indicator for the 'seriousness' of radioactivity to make general sense of the concepts of radio-protection. A number of solutions could be proposed, but the simplest and most understandable one for the public would consist of com paring each incident or accident of exposure to a refer ence situation, chosen by some convention; hence the idea of a 'radioactive decibel'.