Efficient production and purification of 32P radioisotope from sulfur by dry distillation: A practical approach with high radiochemical purity.

The 32P radioisotope, with a half-life of 14.3 days and an energy level of 1.71 MeV, has diverse applications in medicine and research. Consequently, producing a carrier-free 32P radioisotope characterized by high radiochemical and radionuclide purity is imperative. Two primary methods for generating 32P radioisotopes exist: irradiating phosphorus through the nuclear reaction (n,γ) or irradiating sulfur through the nuclear reaction (n,p). Using sulfur as a target material provides several advantages. Besides the fact that the chemical element produced after irradiation (32P) differs from the irradiated element (32S), it also produces a32P radioisotope with a higher specific activity than using 31P as the target. The production of the radioisotope 32P from sulfur employs the dry distillation method, capitalizing on sulfur's easily sublimated nature. The volatility of sulfur when heated makes it easy to separate the resulting sulfur and radioisotope 32P without the need for additional reagents. This research aims to establish a practical method for producing the 32P radioisotope using the dry distillation technique. The dry distillation method utilizes a quartz ampoule containing a mixture of 32P and 35S radionuclides, a distillation tube wrapped with heating tape, and a condenser to collect the distilled sulfur. Sulfur, serving as the target material, undergoes irradiation in the reactor at the Central Irradiation Position (CIP) through the 32S(n,p)32P nuclear reaction with a fast neutron flux of 5.380 × 1013 n/cm2.sec. Separation is achieved through distillation at a temperature of 440 °C. The residual separation products are then dissolved in a 0.1 N HCl solution. The purification process involves using an AG50 WX8 cation exchange resin column, which is pre-conditioned with 0.1 N HCl. The resulting eluate contains the 32P radioisotope. The radiochemical purity of the 32P radioisotope is analyzed using thin-layer chromatography (TLC). In this analysis, a PEI Cellulose plate serves as the stationary phase, and a KH2PO4 solution acts as the mobile phase. This vacuum-free distillation method successfully separates the 32P radioisotope from sulfur, achieving a separation efficiency of 55.1 ± 9.9% (n = 7). The average activity produced after the purification process is 5.690E+10 Bq. Purifying the 32P radioisotope results in a radiochemical purity of 99.97% at Rf 0.7110, as orthophosphate, the radionuclide purity exceeds 99%.

Development of a polystyrene-based microplastic model for bioaccumulation and biodistribution study using radiotracing and nuclear analysis method.

The investigation of micro or nano plastics behavior in the environment is essential to minimize the hazards of such pollutants on humans. While the conventional method requires sophisticated procedures and a lot of animal subjects, the nuclear technique confers a sensitive, accurate, and real-time method using radiolabeled micro or nano plastics as a tracer. In this study, polystyrene sulfonate-based microplastic (PSM) was developed with a size of around 3.6 µm, followed by radiolabeling with iodine-131 (131I) or zinc-65 (65Zn) for microplastic radiotracer model. After a stability study in seawater, phosphate buffer saline (PBS), and human serum albumin (HSA) for fifteen days, PSM-131I remained stable (>90 %), except in HSA (50-60 % after day-9), while PSM-65Zn was unstable (<50 %).

Iodine-131 radiolabeled polyvinylchloride: A potential radiotracer for micro and nanoplastics bioaccumulation and biodistribution study in organisms.

The microplastics amount in the environment is significantly increasing due to human activity, and the hazards are still being investigated. To evaluate the fate of microplastics in organisms, an accurate, fast, and sensitive method is required. Nuclear technology harnessing radiotracer is one of the most sensitive and accurate method for bioaccumulation, biodistribution and biokinetic study. Here, we developed a preparation method for radioiodinated polyvinyl chloride (PVC) as a potential radiotracer of microplastics. Iodine-131 (131I) as a potential radiotracer for microplastic was used in this experiment (activity of 98.05-221.63 MBq). The 131I-PVC was prepared using the Conant-Finkelstein reaction with a solvent combination of phosphate buffer (B), acetone (A), and tetrahydrofuran (T). Such preparation method resulted in spherical 131I-PVC with sizes ranging from 608.6 to 5457.0 nm. Our study showed that acetone is the most suitable solvent for the radioiodination process, resulting in a stable 131I-PVC for up to six days.

Bioaccumulation and retention kinetics of trace elements in the horse mussels Modiolus micropterus exposed to different environmental conditions.

Bioaccumulation studies of Zn and 137Cs by the horse mussel (Modiolus micropterus) were conducted in a laboratory that used radiotracer. The study has been carried out on the effect of cesium and zinc concentrations and the effect of sea seawater salinity on the ability of M. micropterus to accumulate these two contaminants. The uptake of Zn and Cs according to the one-compartment model and the experiment was carried out until the steady-state conditions were reached. The concentration factor at steady-state Zn is 31.94-45.54 mL. g-1 and 23.22-33.26 mL. g-1 which are influenced by the concentration and salinity of seawater, respectively. The concentration factor of 137Cs at steady-state conditions due to changes in concentration and salinity is 3.34-7.55 mL. g-1 and 4.23-9.66 mL. g-1, respectively. The release rates of Zn were 30-47 % and 39-49 % at various concentrations and salinity. The depuration rate from concentration reaching 60 % and salinity at ranges 43-52 % was observed within 10 days after exposure. On the other hand, the release rates of 137Cs were 60 % and 43-52 % at various changes in the concentration and salinity of seawater.

Present status of 137Cs in seawaters of the Lombok Strait and the Flores Sea at the Indonesia Through Flow (ITF) following the Fukushima accident.

Due to thermocline and surface water from the western equatorial Pacific Ocean, which are transported to the Indian Ocean, Indonesian marine waters play an important role in the global ocean circulation. The objective of this study was to assess the spatial distribution of 137Cs in the Lombok Strait as part of a national monitoring program concerning the possible impacts of radionuclides released as a result of the Fukushima accident. Sampling was conducted in the Flores sea and Lombok Strait on 15 to 24 November 2013. Measurements for the Lombok strait showed that 137Cs concentrations at surface layer, thermocline layer and 1000m depth were 0.27Bqm-3; 0.42Bqm-3 and

Radiocesium monitoring in Indonesian waters of the Indian Ocean after the Fukushima nuclear accident.

As data on anthropogenic radionuclide concentrations (i.e., (134)Cs and (137)Cs) in Indonesian marine environments including the Indian Ocean are scarce, offshore monitoring has been performed in the West Sumatra and South Java Seas. The activity concentration of (137)Cs ranges from below minimum detectable activity (MDA) to 0.13Bqm(-3) in the surface seawater of the South Java Sea and from lower than MDA to 0.28Bqm(-3) in the surface seawater of the West Sumatra Sea. The concentrations of (137)Cs in the surface seawater of the West Sumatra and South Java Seas are lower than the estimation of (137)Cs concentration in the subsurface waters owing to the input of the North Pacific Ocean via the Indonesian Throughflow (ITF). The concentrations of (134)Cs in the sampling locations were lower than MDA. These results have indicated that these Indonesian marine waters have not yet been influenced by the Fukushima radioactive release.

Monitoring 137Cs and 134Cs at marine coasts in Indonesia between 2011 and 2013.

Environmental samples (seawater, sediments and biota) were collected along the eastern and western Indonesian coasts between 2011 and 2013 to anticipate the possible impacts of the Fukushima radioactive releases in Indonesia. On the eastern coasts (south and north Sulawesi), the (137)Cs concentrations in the seawater and sediments were 0.12-0.32 Bq m(-3) and 0.10-1.03 Bq kg(-1), respectively. On the western coasts (West Sumatra, Bangka Island, North Java, South Java and Madura island), the (137)Cs concentrations in the seawater and sediments were 0.12-0.66 Bq m(-3) and 0.19-1.64 Bq kg(-1), respectively. In general, the (137)Cs concentrations in the fish from several Indonesian coasts were