|
With the rapid development of technology and social progress, radio, television, communication and power industry, the environment and health of the EMF (Electromagnetic Fields EMF) radiation range and intensity continuously improve the consequent health problems is also well attention. In field of EMF biology research, published in the same topic papers lack of consistency, the coexistence of positive and negative results, and making has brought difficulties to the EMF health risk assessment and health standards. To this end, this dissertation, on the one hand comprehensive assessment of exposure to EMF characteristics, crowd engagement, and the biological effects of innovation proposed the EMF standards to develop the principles and methods, and thus determine the EMF exposure limits. On the other hand, the extremely low frequency electromagnetic fields (ELF-EMF) occupational exposure related epidemiological findings not inconsistent with amyotrophic lateral sclerosis (ALS), this article Meta-analysis of the results of these studies. Part I: environmental the EMF health standards research to the development of China's environmental EMF health standards, we evaluated the EMF human exposure characteristics found different from ordinary chemical substances, widespread, persistent and inevitability, suggesting its potential long-term The cumulative effect in the crowd greatest degree of expression. Therefore, we believe that the development of the EMF limits (eg ICNIRP guide) ignore the long-term cumulative effects of EMF and its potential health hazards, resulting in the current EMF standard is difficult to play a full protective effect on public health risk evaluation method. For this reason, in this thesis, the standard-setting process, we pay more attention to long-term cumulative effects of EMF and potential health effects, and to ensure that the limits of science, rationality and reliability. Based on the a prudent precautionary principle, we re-set the standard strategy: Select scientific data to determine the threshold level, select the safety factor, set the exposure limit, to ensure feasibility. Based on currently available scientific data to determine the frequency electromagnetic fields harm the threshold 50μT, radio frequency electromagnetic fields biological threshold value of 0.4 W / kg (Specific Absorption Rate or SAR). The working frequency electromagnetic fields and radio frequency electromagnetic fields, a safety factor of 50 and 10 respectively Preferences findings uncertainties. Thus, the frequency electromagnetic field exposure limit 1μT, RF EMF exposure limit of 0.04 W / kg. Finally, research and feasibility analysis through our environmental electromagnetic field exposure levels, the set frequency electromagnetic field of the magnetic induction intensity exposure limit of 5μT, electric field strength exposure limit of 4 kV / m; setting radio frequency electromagnetic field exposure limits, or SAR limit of 0.04 W / kg, 10MHz-400MHz, 400MHz-2000MHz, 2GHz-300 GHz-band power density limits were: 1 W/m2 f/400 W/m2 (f is the frequency, in MHz), 5 W / m2 Part II: Meta-analysis of extremely low frequency electromagnetic fields of occupational exposure and amyotrophic lateral sclerosis relationship In order to assess the ELF-EMF occupational exposure and ALS, we use the right keywords from PubMed, EMBASE, and the Cochrane Library and other electronic databases to retrieve meet the inclusion and exclusion criteria (1980-2010), extract the data and related information, and then application STATA11.0 software to verify the consistency of the findings and the corresponding mathematical model data processing, including the heterogeneity test the effect of the value of mergers and impartial assessment. In the combined value of the estimated effect and its 95% CI, homogeneous using the Peto method in the fixed effects model with heterogeneity using the random effects model DL method. Finally, according to the study design, exposure classification and sources of cases were analyzed. All studies have reported the effects of combined value of RR = 1.31 (95% CI = 1.03-1.66), case-control study results combined value of OR = 1.39 (95% CI = 1.05-1.84), cohort study results combined value of RR = 1.21 ( 95% CI = 0.79-1.86). The the exposure classification results under the Occupational name combined value of OR = 1.45 (95% CI = 1.15-1.84), based on the intensity of exposure to ELF-EMFs exposure classification results combined value of the RR = 1.12 (95% CI = 0.88- 1.42). cases the findings from the clinical diagnosis combined value of RR = 2.31 (95% CI = 1.34-3.99), findings from death registration combined value of RR = 1.12 (95% CI = 0.88-1.42). In all studies, found that moderate-intensity heterogeneity. Meta-analysis, we believe that the ELF-EMF occupational exposure may increase the risk of ALS.
|