Studying Submarine Groundwater Discharge at the Cape Ayia: a Multi-Tracer Approach

Purpose. The study of submarine groundwater discharge is one of the most pressing issues of modern hydrogeology and oceanography. The purpose of the paper is to provide a comprehensive study of the submarine groundwater discharge at Cape Ayia using the hydrological, hydrochemical and radiochemical methods, and to determine the flux of submarine groundwater including the nutrients. Methods and Results. The research werecarried out during the coastal expeditions nearby Cape Ayia on March 24, 2019, and on April 22–24, 2019 during the 106th RV “Professor Vodyanitsky” cruise (April 18 – May 13, 2019). The isotopes 226Ra, 228Ra were extracted using the proprietary MnO2-based fibers. After concentration, the sorbent was squeezed to remove excess water, dried and ashed. Then the ash was placed in the Petri dishes and poured with epoxy resin. Activity of the radionuclides was measured on a low-background semiconductor γ-spectrometer with a detector of high-purity germanium (GC3020) 3 weeks after the resin casting. The activity of 226Ra was determined by the daughter radionuclide 214Pb with the energy 351.9 keV (qγ = 37.2 %), and that of 228Ra – by the daughter 228Ac (T1/2 = 6.1 h, qγ = 27.7 %) with the energy 911.6 keV. The basic elements of the main nutrient cycle were determined photocolorimetrically: mineral phosphorus – by molybdenum blue, silicon – by silicon-molybdenum complex. Nitrates (reduced to nitrites) and nitrites were determined by azo dye; ammonium – by indophenol blue also by the photocolorimetric method. Conclusions. Distribution of hydrophysical, hydrochemical and radiochemical parameters in the water area connected with the known submarine groundwater discharges was studied. The distribution of the 226Ra, 228Ra isotopes was studied for the first time. The data on salinity, specific activity of 226Ra, 228Ra and the nutrients concentration permitted to determine the flows of submarine groundwaters in the Cape Ayia area, which amounted to 8220 ± 1200 m3/day. The anthropogenic contribution to pollution of the groundwater forming the submarine sources is shown.

Studying Submarine Groundwater Discharge at the Cape Ayia: a Multi-Tracer Approach

Pupose. The study of submarine groundwater discharge is one of the most pressing issues of modern hydrogeology and oceanography. The purpose of the paper is to represent a comprehensive study of the submarine groundwater discharge focus at the Cape Ayia using the hydrological, hydrochemical and radiochemical methods, as well as to determine the flux of submarine groundwater including the nutrients. Methods and Results. The scientific investigations were carried out during the coastal expeditions nearby the Cape Ayia on March 24, 2019, and also on April 22–24, 2019 during the 106th cruise of the R/V “Professor Vodyanitsky” (April 18–May 13, 2019). The isotopes 226Ra, 228Ra were extracted using the proprietary MnO2-based fibers. After concentration, the sorbent was squeezed to remove excess water, dried and ashed. Then the ash was placed in the Petri dishes and poured with epoxy resin. Activity of the radionuclides was measured on a low-background semiconductor γ-spectrometer with a detector of high-purity germanium (GC3020) in 3 weeks after the resin casting. The activity of 226Ra was determined by the daughter radionuclide 214Pb with the energy 351.9 keV (qγ = 37.2%), and that of 228Ra – by the daughter 228Ac (T1/2 = 6.1 h, qγ = 27.7%) with the energy 911.6 keV. The basic elements of the main biogenic cycle were determined using the photo-colorimetric means: mineral phosphorus – by molybdenum blue, silicon – by silicon-molybdenum complex. Nitrates (reduced to nitrites) and nitrites were determined by azo dye; ammonium – by indophenol blue also by the photo-colorimetric method. Conclusions. Distribution of hydrophysical, hydrochemical and radiochemical parameters in the water area connected with the known focuses of the groundwater submarine discharge was studied. For the first time, the distribution of the 226Ra, 228Ra isotopes was studied. The data on salinity, volumetric activity of the 226Ra, 228Ra isotopes and the nutrients concentration permitted to determine the flows of submarine underground waters in the Cape Ayia area, which amounted to 8220 ± 1200 m3/day. The anthropogenic contribution to pollution of the groundwater forming the submarine sources is shown.

Development of Novel Alumina by Solid-State Reaction for 99Mo/99mTc Adsorbent Material

Technetium-99m (99mTc), a daughter radionuclide of molybdenum-99 (99Mo), is the most widely used radiodiagnostic agent due to its ideal characteristics. The separation of this radionuclide from 99Mo is commonly performed using alumina. However, a new production method of this radionuclide, which employs a low specific activity 99Mo, makes alumina no longer suitable as separation material. This study aims to develop novel alumina using a facile solid-state reaction for 99Mo/99mTc generator system. The SS-alumina was synthesized from aluminium nitrate nonahydrate and ammonium bicarbonate without solvent. The resulted SS-alumina was then analyzed by FTIR and BET method. 99Mo adsorption and 99mTc releasing study on a series of pH were also performed. FTIR study revealed that the resulting material was Al2O3 with a surface area of 237.65 m2/g. The adsorption capacity, 99mTc yield, 99Mo breakthrough, and alumina breakthrough were 76.06 mg Mo/g alumina, 80.31%, 56.5 µCi/mCi 99mTc, and less than 5 mg/mL, respectively. The elution profile shows a high activity of 99mTc in 2nd and 3rd fraction. It is concluded that the SS-alumina shows good performance as adsorbent material for separation of a 99Mo/99mTc and further work is now underway.

Separation of Micro-Macrocomponent Systems: 149Pm – Nd, 161Tb-Gd, 166Ho-Dy and 177Lu-Yb by Extraction Chromatography

<p>¹⁴⁹Pm, ¹⁶¹Tb,¹⁶⁶Ho, and ¹⁷⁷Lu have advisable nuclear properties to be used in radiotherapy. They can be produced by neutron irradiation of a lanthanide target followed by β^- decay and a posterior radiochemical separation of micro-amounts of daughter radionuclide from macro-amounts of the parent target. In order to accomplish the radiochemical separation of micro-macro systems: Nd/¹⁴⁹Pm, Gd/¹⁶¹Tb, Dy/¹⁶⁶Ho and Yb/¹⁷⁷Lu, this work proposes the use of an extraction chromatographic with Ln SPS resin. Distribution coefficients and separation factors were determined and established the separation conditions of these micro-macro systems.</p>

PEMBUATAN RADIONUKLIDA MOLIBDENUM-99 (99Mo) HASIL AKTIVASI NEUTRON DARI MOLIBDENUM ALAM UNTUK MEMPEROLEH TEKNESIUM-99m (99mTc)

PEMBUATAN RADIONUKLIDA MOLIBDENUM-99 (99Mo) HASIL AKTIVASI NEUTRON DARI MOLIBDENUM ALAM UNTUK MEMPEROLEH TEKNESIUM-99m (99mTc). Pembatasan penggunaan uranium sebagai target untuk produksi 99mTc menyebabkan rumah sakit di Indonesia kesulitan mendapatkan pasokan 99mTc. Saat ini 99mTc diperoleh dari 99Mo hasil fisi (pembelahan uranium). Pembuatan radionuklida 99Mo dari aktivasi neutron molibdenum alam (MoO3) di teras reaktor G.A Siwabessy digunakan sebagai metode alternatif untuk memperoleh 99mTc. Tujuan penelitian ini adalah untuk melakukan pembuatan radionuklida 99Mo dari aktivasi neutron molibdenum alam untuk memperoleh 99mTc. Serbuk MoO3 alam sebanyak 5 gram dikemas dalam ampul kuarsa dan dimasukkan ke dalam inner capsul selanjutnya dikemas menggunakan outer capsul sebagai bahan target. Bahan target diiradiasi di reaktor G.A Siwabessy selama 100 jam. Hasil perhitungan diperoleh aktivitas 99Mo sebesar 65 % dari nilai maksimum yang dapat diperoleh. MoO3 paska iradiasi dilarutkan dengan NaOH 4 M sehingga diperoleh larutan natrium molibdat (Na2MoO4). Radionuklida 99Mo dan 99mTc diukur menggunakan spektrometer gamma. Radionuklida 99Mo terdeteksi dalam produk larutan Na2MoO4 dengan aktivitas jenis 99Mo yang diperoleh sebesar 0,81 Ci 99Mo/g Mo. Radionuklida anak luruh 99mTc dipisahkan dari radionuklida induk 99Mo menggunakan kolom pemisah yang berisi material berbasis zirkonium (MBZ) sebagai penyerap 99Mo. Radionuklida 99mTc hasil pemisahan diperoleh dalam bentuk natrium pertehnetat (Na99mTcO4).dengan recovery yang masih rendah yaitu sekitar 52 hingga 71 %.Kata kunci: Molibdenum, teknesium, radionuklida, pemisahan, iradiasi. PRODUCTION OF ACTIVATED NEUTRON MOLYBDENUM-99 (99Mo) RADIONUCLIDE FROM NATURAL MOLYBDENUM TO OBTAIN TECHNETIUM-99m (99mTc). Uranium usage restriction causes the hospitals in indonesia difficult to obtain the suply of 99mTc. At Present, 99mTc is obtanied from molybdenum as a uranium fission product. Production of 99Mo radionuclide resulted from neutron activated natural molybdenum (MoO3) in G.A Siwabessy reactor could be used as a alternatif method for producing 99mTc. The aim of this research is synthesize of 99Mo radionuclide from neutron activated natural molybdenum (MoO3) to obtain 99mTc. The five grams of MoO3 powder was packed in a quartz ampule and inserted into inner capsule then also inserted into outer capsule as a target material. It was iradiated in G.A Siwabessy reactor for 100hours. Based on theoritical calculation, about 65 % of maximum 99Mo activity could be recovered. After Irradiation, MoO3 was dissolved by NaOH 4 M solution so it was natrium molybdate (Na2MoO4) solution. 99Mo and 99mTc radionuclide were analyzed using gamma spectrometer. 99Mo radionuclide was detected on Na2MoO4 solution as product that had specific activity of 0.81 Ci 99Mo/ g Mo. 99mTc as daughter radionuclide was separated from 99Mo as parent radionuclide using separated column containing zirconium based material (ZBM) as 99Mo adsobent. 99mTc radionuclide has been succesfully separated using ZBM column although recovery of 99mTc was quite low in which approximately 52 to 71 %. The 99mTc radionuclide was recovered in the form of sodium pertechnetate (NaTcO4) solution.Keywords: Molybdenum, technetium, radionuclide, separation, irradiation.