Authors:K. Szczepaniak, A. Astel, P. Bode, C. Sârbu, M. Biziuk, E. Raińska, and K. Gos
The study was performed in an urban area to identify the main pollution sources. Dry and living bog moss samples were exposed
in parallel, and their accumulative capability as biomonitoring tools was compared. The procedures of moss exposure, preparation,
and element concentration measurement performance are recommended. Chemical composition of moss material was determined using
instrumental neutron activation analysis in a research reactor located in Delft, the Netherlands. The element concentration
levels were lower in living moss than in dry one. Chemometric methods were suggested to identify specific element profiles
attributing to factors impacting moss composition in various urban locations.
Authors:F. Tagliaferro, E. De Nadai Fernandes, M. Bacchi, P. Bode, and E. Joacir De França
Depending on the harvest conditions, coffee beans can be contaminated by soil when dropped to the ground. It is well known
that agricultural soils act as sinks for agrochemicals applied to the crops. While coffee is brewed, substances present in
the roasted and ground coffee beans are extracted by hot water, emphasizing the need to assess the possible transfer of impurities
from the soil to the beverage. Soil-contaminated samples of roasted coffee beans were split into 2 groups according to the
treatments: (a) washed and ground and (b) only ground. Brewing was performed in a household espresso machine for both coffees.
The resulting beverage was freeze-dried and the elemental composition determined by instrumental neutron activation analysis
(INAA). The mass fractions of the terrigenous elements Fe, La, Sc, Sm and Th in the freeze-dried non-washed coffee beverages
were, at least, 2 times higher than in the washed samples. These elements are tracers of the soil, indicating that the impurities
from the soil reached the beverage.
Authors:M. Bacchi, L. Santos, E. De Nadai Fernandes, P. Bode, F. Tagliaferro, and E. França
The effectiveness of a Compton suppression system (CSS) for instrumental neutron activation analysis of plant materials was
evaluated. Suppression factors were measured with 137Cs sources. Five certified reference materials were analyzed and the detection limits calculated from both suppressed and
unsuppressed spectra were compared. The CSS demonstrated to be useful for lowering the detection limits of ten out of sixteen
elements tested, showing a maximum improvement factor of 3.9. The system performance was strongly influenced by the sample
composition and also by the measurement conditions, indicating the importance of testing each individual sample type and analytical
Authors:M. Vasconcellos, P. Bode, G. Paletti, M. Catharino, A. Ammerlaan, M. Saiki, D. Fávaro, A. Byrne, R. Baruzzi, and D. Rodrigues
Biomonitoring of mercury contamination of Brazilian Indian population groups living in the Xingu Park, a reservation situated in the Amazonic region, has revealed very high levels of mercury in hair samples as compared to controls. Total mercury was determined by INAA in most of the tribes living in the Park and methylmercury was determined by CVAAS in samples with total mercury above 10 mg/kg. Due to the fact that selenium seems to protect animals against the toxic effects of methylmercury, it was considered also of interest to determine its concentrations in the hair samples with very high mercury levels. Selenium was determined by INAA via the short-lived radionuclide 77mSe (T1/2 = 17.45 s). The correlations between selenium and mercury concentrations in Brazilian controls and in the Indian population groups are discussed.
Authors:N. Tsibakhashvili, L. Mosulishvili, E. Kirkesali, I. Murusidze, M. Frontasyeva, S. Pavlov, I. Zinicovscaia, P. Bode, and Th. van Meerten
Instrumental neutron activation analysis was used to study accumulation of Hg(II) and Cr(VI) ions in Arthrobacter globiformis 151B, a gram-positive, Cr(VI)-reducer aerobic bacterium isolated from basalt sample taken from the most polluted region in
the Republic of Georgia (Kazreti). Experiments were focused on (1) accumulation of Hg(II) in bacterial cells; (2) accumulation
of Cr(VI) in A. globiformis 151B in the presence of Hg(II) and (3) effects of Hg(II) and mixture of Cr(VI)–Hg(II) on the elemental composition of bacteria.
It was shown that this bacterial strain possesses uptake mechanisms by which mercury toxicity can be reduced in environment
and that accumulation of Cr(VI) in A. globiformis 151B is much higher in the presence of Hg(II) ions. Accumulation of Hg(II), similar to the Cr(VI) accumulation, follows well
the Lengmuir–Freundlich model. NAA measurements showed increased content of Fe in bacteria under Hg and Cr action, suggesting
that Fe-containing biomolecules play a decisive role in detoxifying of heavy metals by A. globiformis 151B. A concentration of 5000 μg/L of Hg(II) was found to be critical for A. globiformis 151B. At this concentration of Hg(II) the concentrations of both essential (Na, Mg, Al, Cl, K, Mn, Zn) and some non-essential elements
(Rb, Sb, Sc, As) changed drastically along with a decrease of the biomass of bacteria by a factor of two. One may assume that
under this high exposure to Hg(II) the structure of the bacterial cell wall was destroyed.