Methods of evaluation of genetic hazards by environmental mutagens and radiations were reviewed. Problems with chemicals, similar and dissimilar to ionizing radiations, were pointed out. Synergisms and antagonisms in genetic effects between chemicals and radiations were classified and discussed. Adoption of REC (rem-equivalent-chemical) should be re-examined with many cautions.
The data of the “effective energies” which are necessary for the evaluation of the MPC values are listed in the form of a table. From this table one can easily find a necessary effective energy. The effective half-life can be found from a given graph. The terms carrying a time parameter are all represented graphically. The MPC values for several short-lived nuclides were calculated by the present method, and the results were compared with the values obtained from a strict method. The errors were less than 10%.
This is a literature survey of chest retention of inhaled CO-60 in humans. Only the reports which followed up the retention for more than 100 days after inhalation were picked up. The chest retention patterns reported in the literature falled into three types and none of them agreed with the ICRP lung model. Two types of chest retention have been reported in dogs which inhaled two different chemical forms of Co (i. e. CO3O4 and COO). The difference among the chest retention patterns reported in humans may be attributable to the difference of chemical form of CO inhaled. For the convenience of the calculation of the committed dose equivalent in the lungs, one of the effective retention functions, which might not include the initial rapid clearance, was expressed as a sum of two exponentials as follows, (chest retention)=0.53exp(-0.693t/110)+0.47exp(-0.693t/440) The initial rapid clearance does not effectively affect the estimate of the committed dose equivalent.
The consumption of eight categories of marine foods was surveyed on two kinds of families in Oarai town, one of the famous fishing towns in Ibaraki prefecture. The average daily intake of whole marine foods through a year of 1973 was 255g/d/p for fisherman's families and 166g/d/p for non-fisherman's, respectively. Fisherman's families showed higher consumption of all categories of marine foods except algae than non-fisherman's. Seasonal variation of marine food consumption was observed for both families, i. e., the consumption in spring was less than that in the other seasons. One half of the total marine foods consumption was occupied by fishes. And among three kinds of fishes, high consumption of pelagic fish was recognized. These consumption aspects were almost similar to those ovserved in Kuji, Tokai and Nakaminato as reported previously.
The detection methods for 129I now prevailing are based roughly on two different principles: one is the direct method such as the liquid scintillation method and X-ray detection method by use of the intrinsic Ge detector and the other is neutron activation method. The detection limit of the direct method is about 1dpm of 129I, while that of the neutron activation method, though it changes with the irradiation conditions, can reach the level of 10-4 to 10-6dpm. A lot of data have been reported by means of those methods on the environmental materials such as water, milk, soils, vegetation and thyroid of animals and human-beings. In this review, the level of 129I in the environment is briefly stated first, and then the individual detection methods and the pretreatments required for each measurement are referred.