Authors:Sara Darvishi, Mohammad Ardakani, Saeed Vazan, Hossein Ghafourian, Farzad Paknejad, and Amir Faregh
Activated carbons (AC) have been long recognized as prominent absorbents in industries and feature numerous applications in
preventing or absorbing the harmful gases and liquids and could be employed for filtration and remediation or even reutilization
of chemicals. In order to investigate the capacity of AC in reducing the absorption of heavy metals (HM) including lead (Pb)
and cadmium (Cd) and dual complex (Pb × Cd) by spinach, a factorial experiment in a completely randomized design with three
replications on a pot trial was conducted. Three factors including five levels of AC 0, 5000, 10000, 15000, 20000 mg/kg soil,
one concentration level of Pb 4,000 mg/kg soil and one concentration level of cadmium Cd 8 mg/kg soil were tested. The index
of heavy metal concentration was calculated in leaf, stem and root and their corresponding dry weights. Results illustrated
that in contaminated soils, plants with AC exhibited a superior reduction of absorption of HM vis-à-vis the plants without
AC. The foremost result regarding the impact of AC on reducing the concentration of Pb and Cd was observed in 20,000 level
of AC. This reveals that AC declined the soil contamination and lessened the accumulation of HM into the shoots and roots.
Results suggest that the application of AC may be an eligible solution for decreasing the translocation of HM into the plants.
Authors:M. Frontasyeva, V. Nazarov, and E. Steinnes
Instrumental activation analysis (INAA) based on irradiations in a nuclear reactor with particularly high relative fluxes of resonance and fast neutrons has been shown to open new possibilities for multi-element surveys of mosses used as monitors of atmospheric deposition. Comparison is made with data obtained by inductively coupled plasma-mass spectrometry (ICP-MS) and conventional INAA. Data for 15 elements not previously investigated in routine moss studies are presented, e.g., Zr, Sn, Hf, Ta, W, Au, Th, and the rare earth elements Ce, Nd, Eu, Gd, Tb, Tm, Yb, Lu. Other elements particularly well determined by this approach are Sc, Co, As, Ag, Sb, Cs, La, Sm, Th, and the non-metallic trace elements Se, Br, and I. Advantages and drawbacks with the high fast neutron component are discussed.
k0-Standardized INAA was applied to the determination of heavy elements in two lichen varieties of the speciesParmelia: caperata andsulcata. The aim was to find out differentiations between the two varieties concerning the accumulation of elements from the air. The samples were collected at about 70 locations randomly chosen in the whole country (Portugal). It was found a similar local variation for both species, between 20–25%. From the comparison it was observed thatParmelia sulcata accumulates larger amounts of most of the elements determined thanParmelia caperata; only Ca is more accumulated by thecaperata and Hg are similarly absorbed by both varieties. Therefore, it was concluded thatParmelia sulcata should be preferred as bioaccumulator when both varieties are present. Some pollution sources were identified, but the sampling net was too short to obtain an exhaustive identification. The quality control was made using NIST and IAEA reference materials: an accuracy of ±10% was found. The precision has also been estimated: it is better than 11% except for Hg (15%), Sr (13%), Ti (19%) and Mg (32%).
The knowledge of the chemical forms of metals is used to assess their availability and uptake by plants, and in sediments the forms of metals determine their transport and mobility in the aquatic media. This information may be obtained by determining chemical forms of metals (speciation) or different phases in which the metals are bound, obtained by applying extraction schemes. The analytical methods used include different steps and all of them must be validated. We report here the recommendations to minimize the errors in this kind of analysis. For validation the use of Certified Reference Materials (CRMs) and the participation in interlaboratory exercises are highly recommended.
Authors:M. Rakovič, E. Latýnová, V. Foltýnová, S. Výborný, J. Kučera, N. Pilecká, and A. Glagoličová
For systematic checking of the feasibility of determining elements by INAA in scalp hair, pubic hair and toenails, three different regimes were employed by varying the activation time and cooling time prior to -ray spectrometric measurements. The combination of these three regimes (activation time 1 min, cooling time 10 min; activation time 5 h, cooling time 5 d; activation time 5 h, cooling time 30 d) made it possible to determine the following 20 elements in most samples: Al, As, Br, Ca, Ce, Cl, Co, Cr, Cu, Fe, Hg, I, K, La, Mn, Na, S, Sb, Se, Zn. Further 10 elements (Ba, Cd, Mo, Ni, Rb, Sc, Sm, Th, V, W) were detectable only in some samples, however, with a fairly good precision, so that they could be detected in this way in the case of elevated concentrations exceeding physiological limits.
Authors:B. Markert, O. Wappelhorst, V. Weckert, U. Herpin, U. Siewers, K. Friese, and G. Breulmann
Biomonitoring is a method of observing the impact of external factors on ecosystems and their development over a long period,
or of ascertaining differences between one location and another. A monitor suitable for the subject of the investigation must
be chosen, and the comparability of the element concentrations thus determined (both within the investigation and with other
studies) must be ensured by adhering to precise sampling guidelines. In addition to the small amount of equipment required,
the advantages of biomonitoring lie in the ecosystem approach that permits conclusions going beyond the biomonitor itself.
Attention has to be given to the factors that may affect element concentrations and which can lead to incorrect statements
Radionuclide X-ray fluorescence method with a Si/Li semiconductor detector and238Pu exciting source was used in the determination of Cr, Fe, Ni, Cu, and Zn content in industrial wastewaters. Simultaneously, the effects of the wastewaters on activated sludge biocenose were evaluated.
Pot experiments were carried out to assess the influence of two plantspecies on chemistry of polluted and unpolluted urban soils. Change in pHand acid neutralization capacity of the soils, as well as variations in elementalcomposition of soil leachates and in total concentrations of elements in thesoil were studied by INAA and ICP-AES. Concentrations of 28 elements in plantswere determined by INAA. Cultivation of plants led to significant change insoil parameters. In particular, acid neutralization capacity of polluted soilincreased, resulting in increase in element uptake.
Eight soil profiles developed on crystalline basement complex rocks in the semi-arid region of Nigeria were analyzed for total contents of cesium (Cs), chromium (Cr), cobalt (Co), hafnium (Hf), iron (Fe), lanthanum (La), lutetium (Lu), scandium (Sc), thorium (Th), uranium (U) and ytterbium (Yb). The contents range from 50.3–95.4 Cs, 16.1–58.1 Cr, 0.6–9.0 Co, 9.0–34.8 g g–1 Hf, 0.31–3.69% Fe, 17.2–60.7 La, 60.4–90.6 Lu, 2.6–12.6 Sc, 8.3–21.5 Th, 4.7–9.2 U and 3.6–92 g g–1, Yb. Their corresponding means were 68.4, 35.1, 4.0, 19.9 g g–1, 1.70%, 37.1, 79.4, 6.5, 14.7, 6.7 and 5.0 g g–1. In general, total Cs, Co, Fe, La, U and Yb increased with further increase with depth. On the other hand, Lu, Sc and Th showed no distinct vertical distribution within the profiles. All eleven elements were correlated with the amounts of clay present in the soils, the correlation being stronger for Cs, Th, Yb, Cr and Lu.