Chemical warfare agents have been stockpiled for almost a decade and their destruction has become an environmental issue that
will continue to require attention for many years. There are hundreds of thousands of tonnes yet to be destroyed, and the
current chemical or incineration techniques are not without problems. While many researchers are seeking better chemical techniques,
we decided to try ionizing radiation to destroy sulphur mustard with the goal of producing non-toxic products. We irradiated
a variety of sulphur mustard samples by both a mixed field source (β, γ and neutrons) and a pure gamma source. The mixed field
irradiation of wet sulphur mustard for long irradiation times was the most successful at destroying the chemical agent.
Authors:K. Inn, B. Coursey, E. Eisenhower, M. Walker, H. Heaton, and K. Duvall
Over the past ten years, the National Institute of Standards and Technology has, through its Office of Radiation Measurement, developed a national program for Secondary Laboratories. These Secondary Laboratories provide the necessary calibrations and quality assurance testing to support and affirm the caliber of the measurements in the areas they serve. The areas that are in the program include State Radiation Protection, Personnel Dosimetry, Survey Instrument Calibration, High-Level Dosimetry, Radiation Therapy, Bioassay, Survey Instrument Testing, Ionizing Radiation, Environmental Radioactivity, Radioactivity Standards, and Radon.
Authors:M. N. Mori, H. Oikawa, M. H. O. Sampa, and C. L. Duarte
Chlorpyrifos is an organophosphate pesticide commercialized since 1965 and it is now one of the top five commercial insecticides.
It is registered for use in over 900 different pesticide formulations in the world. Chlorpyrifos poisoning usually affects
many organs of the body, such as the central and peripheral nervous system, eyes, respiratory system, and the digestive tract.
Depending on the pesticide formulation and type of application, chlorpyrifos residues may be detectable in water, soil, and
on the surfaces from months to years. This paper presents preliminary studies of the removal of chlorpyrifos by exposition
to ionizing radiation, to be applied in pesticide container decontamination. Samples containing various concentrations of
chlorpyrifos in acetonitrile were irradiated with absorbed doses varying from 5 to 50 kGy, using a 60Co gamma-source with 5,000 Ci activity (Gamma cell type). The chemical analysis of the chlorpyrifos and the by-products resulted
from the radiolitic degradation were made using a gas chromatography associated to mass spectrometry (GC-MS) and gas chromatography
with flame ionization detector (GC-FID).
Authors:Barbara Marciniec, M. Stawny, M. Kozak, and M. Naskrent
effect of ionizing radiation on the physicochemical properties of chloramphenicol
in solid state has been studied. The compound was e-beam irradiated with doses
from the range 25–400 kGy and the possible changes were detected in
the organoleptic methods (colour, form, odour, solubility and clarity), by
SEM observations, X-ray, chromatography (TLC), spectrophotometry (UV, IR,
EPR) and thermal (DSC) methods.
No significant changes relative
to the unirradiated sample were observed as a result of irradiation with the
dose of 25 kGy – a standard dose for radiation sterilization, besides
free radicals generation. Higher doses were found to produce a change in colour,
increase in absorbance (UV), changes in the XRD spectra and appearance of
products of radiolysis. The presence of the radiolysis products was confirmed
by the TLC method, indirectly by DSC showing a decrease in the melting point
from 0.2 to 4.5C and enthalpy from 3.8 to 23.3 J g–1,
respectively. A linear relationship was obtained between the irradiation dose
(25–400 kGy) and the melting point of chloramphenicol, characterised
by the correlation coefficient r=0.9968.
The EPR signal intensity increased with increasing dose of irradiation
and the lifetime of the free radicals was longer than 6 months. No changes
were detected in SEM and IR spectra.
As follows from our results,
the DSC method is most suitable for a fast monitoring of the drugs subjected
to sterilization by irradiation as it permits detection of changes occurring
even on irradiation with low doses and their quantitative description.
Authors:J. Petushkova, N. Lyalikova, and F. Nichiporov
The effect of60Co -rays and detergents on bacteria isolated from monuments has been studied. Most of the heterotrophic bacteria examined were found to be resistant to radiation, whereas nitrifiers are moderately radio-resistant. The most effective growth supression of microorganisms was observed with the simultaneons application of ionizing radiation and detergents.
Authors:M. Evora, L. Machado, V. Lourenço, O. Gonçalez, H. Wiebeck, and L. de Andrade e Silva
The aim of this work is to study the ionizing radiation effects on thermal properties of there cycled polyamide-6. This polymer
was irradiated with an electron beam of 1.5 MeV with different doses. The thermal properties of the samples were determined
by TG, DSC and DMA measurements. It was observed that the irradiated samples of recycled polyamide-6undergo a crosslinking
Effects of ionizing radiations on organic ion exchangers are recognized as a vexing problem in the processing of special nuclear materials and high specific activity radioactive waste forms. An extensive literature survey, started in 1976 and updated periodically, indicates that radiation decomposition of ion exchange materials has the potential for a variety of undesirable consequences. It is also apparent from this survey that systematic efforts to identify and resolve these problems and to develop radiation resistant ion exchangers are extremely limited. There is, however, widely scattered information in the literature that is useful in designing and operating ion-exchange-based process systems with reasonable assurance of safety. The compilation of experimental data presented in this paper can contribute to better design and safer operations of synthetic organic ion exchange systems at nuclear material processing facilities.
Authors:K. C. S. Almeida, H. Oikawa, J. Oliveira, and C. L. Duarte
A major concern with leaking petroleum is the environmental contamination by the toxic and water-soluble components such as
benzene, toluene and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant
toxicity. All BTX compounds are depressants to the central nervous system. Consequently, BTX are priority pollutants and their
occurrence has led to the development of several physical, chemical and biological methods for their removal. The use of nuclear
technology for protection and conservation of the environment, by the destruction of toxic organic compounds present in the
environmental, drinking water, soils and industrial sewage has been the object of study of several authors in Brazil and in
the world. The objective of this paper is to present the preliminary results of the study of contamination of the seawater
by the main pollutants of the output and transport of petroleum, such as benzene, toluene and xylene, and their removal by
the exposure to the ionizing radiation.
The spectrometric system for ionizing radiation measurement with pile-up rejection and counting losses correction has been described. The results for HpGe, Ge(Li), Si(Li) and surface barrier detectors have been presented. The total count rate ranged from 500 to 105 cps and different radioisotopes have been used. The counting losses correction accuracy has been within ±1% with tenfold reduction of background from pile-up pulses. The possibility of the system application for radiation intensity measurement of the mixture of short- and longlived radioisotopes has been discussed.