Authors:R. Fujiyoshi, Y. Satake, T. Sato, T. Sumiyoshi, J. Dietz, and R. Zimmermann
Environmental radionuclides (40K, 137Cs, 210Pb, 226Ra) were determined in soils under semi-arid stands, a transition area from thorn to deciduous forest in El Angolo, and heath
stands in the Alto Mayo in Northern Peru in order to elucidate their activity level in soil, and to trace underground environment
in remote areas of little anthropogenic intervention. Anthropogenic 137Cs was only found in the uppermost portion of the soils in small amount, whereas the 210Pb activity was exceptionally high at the soil surfaces in a tropical stand of Alto Mayo. The results suggest a fallout nuclide,
210Pb, having been transported from local source(s) not to be specified yet.
Authors:Raquel Bombarda Campanha and Célia Maria Landi Franco
Materials and methods
Roots of cassava ( Manihot esculenta ), sweet potato ( Ipomoea batatas ), Peruvian carrot ( Arracacia xanthorriza ), and potato tubers ( Solanum tuberosum ) were used in this study
Neutron activation analysis was used to determine the concentration of trace elements in 50 samples of orange, yellow, honey, green, blue and pink opals as well as 18 samples of colourless opals taken from a number of recognised fields in Australia, Peru, Mexico and USA. The results were evaluated to determine the relationship between trace element content and opal colour.
The National Bureau of Standards has, for the past five years, been developing natural-matrix, environmental-level radioactivity Standard Reference Materials in large quantities to be available to users over a ten year time period. These materials have been found to be useful for the evaluation of radiochemical methods and analysis, as interlaboratory comparison materials, and as quality assurance materials. To date, six Standard Reference Materials have been issued: River Sediment, Human Lung, Human Liver, Rocky Flats Soil-1, Freshwater Lake Sediment, and Peruvian Soil. The concentrations of twenty radionuclides have been certified in these materials.
Authors:P. Bedregal, B. Torres, M. Ubillús, P. Mendoza, and E. Montoya
The chemistry laboratory at the Peruvian Institute of Nuclear Energy (IPEN) has carried out a validation method for the samples
of siliceous composition. At least seven variables affecting the robustness of the results were initially identified, which
may interact simultaneously or individually. Conventional evaluation hereof would imply a massive number of analyses and a
far more effective approach for assessment of the robustness for these effects was found in the Youden-Steiner test, which
provides the necessary information by only eight analyses for each sample type. Three reference materials were used for evaluating
the effects of variations in sample mass, irradiation duration, standard mass, neutron flux, decay time, counting time and
Authors:Eduardo Montoya, Pablo Mendoza, Patricia Bedregal, Oscar Baltuano, and Isaac Cohen
A method that combines the use of non-destructive neutron activation analysis and high-resolution α spectrometry has been
developed for determination of the activities of 234U and 238U in geological samples of low uranium content. The 238U content is determined by k0-based neutron activation analysis, whereas the 234U/238U relationship is measured by α spectrometry after isolation and electrodeposition of the uranium extracted from a lixiviation
with 6 M HCl. The main advantage of the method is the simplicity of the chemical operations, including the fact that the steps
destined to assure similar chemical state for the tracer and the uranium species present in the sample are not necessary.
The method was applied to soil samples from sites of the North Peru Coast. Uranium concentration range 3–40 mg/kg and the
isotopic composition correspond to natural uranium, with about 10% uncertainty.
an ammoniated hydrogen sodium phosphate and is found in caves in Western Australia and is especially known from the Petrogale Cave, near Madura, Western Australia. The mineral has also been found at Ichaboe Island, Namibia and Gua~nape Island, Peru
Authors:Susan Moreno-Molek, Salaam Saleh, Druthiman Reddy Mantheni, Manik Pavan Kumar Maheswaram, Tobili Sam-Yellowe, and Alan T. Riga
Gamboa , D , Ho , MF , Bendeezu , J , Torres , K , Chiodini , PL , Barnwell , JW , Incardonas , S , Perkins , M , Bell , D , McCarthy , J , Cheng , Q . A large proportion of P. falciparum isolates in the Amazon region of Peru lack