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Instrumental neutron activation analysis (INAA), inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were used for the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco). The reliability of the results was checked, by using IAEA Soil-7 certified reference material. Results obtained by the three techniques were compared to control digestions efficiencies. A general good agreement was found between INAA and both ICP-MS and ICP-AES after alkaline fusion (ICPf). The ICP-MS technique used after acid attack (ICPa) was satisfactory for a few elements. A principal component analysis (PCA) has been used for analyzing the variability of concentrations, and defining the most influential sites with respect to the general variation trends. Three groups of elements could be distinguished. For these groups a normalization of concentrations to the central element concentration (that means Mn, Si or Al) is proposed.

The heavy metals bio-accumulation ability of algae was studied along the North Atlantic Morrocan coast. Instrumental neutron activation analysis was used, to determine concentrations of various elements. The k 0 standardization method was used. Some interferences corrections, particularly due to high concentrations of uranium were applied. The quality of the method was checked by using the CRM 140, a Fucus provided by IAEA. Important pollutions appear for several heavy metals from the Morrocan phosphate industry, with respect to the natural background environment.

There is a need to know, before dismantling nuclear plants, how the induced radioactivity is distributed in concrete. Computer codes are used to predict such a distribution, by applying input data like, among others, the chemical composition of the material. Biological shield concretes with particularly high boron or barium concentrations had to be analyzed. Instrumental neutron activation analysis is not able to determine all elements, thus, additional techniques are required, like ICP-MS and ICP-AES. The respective performances of these techniques are discussed. For INAA, the thermal neutron self-shielding was empirically corrected by using comparisons between thermal neutron activation (TNAA), epithermal and fast neutron activation (ENAA), ICP-AES and ICP-MS measurements.

The Moroccan phosphate industry releases large amounts of heavy metals in the Atlantic Ocean in the surroundings of two places: Safi and Jorf Lasfar. The major waste, called phosphogypsum and composed of calcium sulphate and other additional salts, is introduced into sea water in particulate form. After dissolution of the particles, heavy metal concentrations can be influenced near the release point. Two multi-element analytical techniques were used to measure 47 element concentrations in various materials involved in the study of the phosphate pollution: Inductively Coupled Plasma Mass Spectrometry (ICPMS) and instrumental neutron activation analysis (INAA). At first, phosphate and phosphogypsum were characterized in order to recognize the overall features of the heavy metal pollution source. From the yearly amount of phosphogypsum produced by the Moroccan industry and the element concentrations in phosphogypsum, it has been possible to estimate a yearly flux of heavy metals introduced in the Atlantic Ocean. Algae were used as bio-accumulator materials of heavy metals in the marine environment, in the region of Jorf Lasfar, in order to significantly reveal the signal of the heavy metal pollution. Ulva lactuca Linnaeus was selected to assess heavy metal pollution around the waste release point. Accumulation factors were determined for 47 elements in U. lactuca, by comparing mean concentrations obtained in algae collected in non-polluted sites (background sites) and an average sea water concentration given in the literature. The ratio between the concentration in U. lactuca, collected in a polluted site to the background concentration in U. lactuca, was determined, giving an estimate of the pollution factor for the same elements by the phosphate industry. The decrease of the pollution due to the dilution in the sea water was observed as far as 6 km southward of the release point. A specific variation was observed for lead and its isotopic composition, denoting that the phosphate industry is not the only pollution source in this region. Natural processes were likely involved to induce the lead concentrations variations along the littoral.

In order to investigate the seasonal and geographical distribution of snow concentrations anddeposition fluxes of environmentally relevant ionic species in the Alps, the international programSNOSP was initiated. In the framework of this program, intercomparisons of snow samplingtechniques and analytical methods to determine the ionic species C1-, NO 3 - ,SO 4 2- , K+, Na+, NH4 +, Mg2+, and Ca2+, as well as the pH and the specificconductivity were performed. The concentrations of these species in the snow samples collectedin the SNOSP program varied by orders of magnitude with, e.g., concentrations of NO 3 - , SO 4 2- , and NH4 + ranging from 0.2-60, 0.2-90, and 0.1-60 µeq L-1,respectively. The intercomparisons revealed a reasonable agreement of the determinations of thespecies Cl-, NO 3 - , SO 4 2- , Na+, and NH4 + in snow. Results were less satisfactory for K+, Mg2+, Ca2+,and H+, mainly due to the very low concentrations. In conclusion, recommendations areformulated for the reliable derivation of chemical inventories from snow packs.

Theko-standardization method has been extensively used in the Pierre Sue laboratory during the last few years. We had developed two different new programs which both used parts of a commercial package (Canberra or Nuclear Data), for example: isotope parameter editor, automatic peak search, nuclide identification. However, further adaptation of these packages is not easy, due to the specific data handling of the two programs. In order to overcome these constraints, we decided to write a completely new program, Ko-LABSUE, which is as independent of the manufacturer specifications as possible. All of the different steps of theko-quantification (automatic peak search, nuclide identification, calculation of elemental concentration etc.) are processed by modules written in TURBO-PASCAL. Only two “unit” modules have to be re-written to process manufacturer data files of different formats: the modules used to read the spectrum data and the detector efficiency curve. This program runs on an IBM-PC and is currently on “β-test” in our laboratory.

Biomass burning, in a broad sense, encompasses different burning practices, including open and confined burnings, and different types of vegetation. Emission factors of gaseous or particulate trace compounds are directly dependent both on the fuel type and the combustion process. Emission factors are generally calculated by stoichiometric considerations using the carbon mass balance method, applied either to combustion chamber experiments or to field experiments based on ground-level measurements or aircraft sampling in smoke plumes. There have been a number of experimental studies in the last 10 years to investigate wildfires in tropical, temperate, or boreal regions. This article presents an overview of measurement methods and experimental data on emission factors of reactive or radiatively active trace compounds, including trace gases and particles. It focuses on fires in tropical regions, that is, forest and savanna fires, agricultural burns, charcoal production, use of fuelwood, and charcoal combustion.

Human-induced change in the composition of the atmosphere seriously threatens the global climate. In an effort to address this threat, 161 nations signed the United Nations Framework Convention on Climate Change at the Earth Summit in Rio de Janeiro in June 1992. The ultimate objective of this international agreement is to achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. As of the first session of the Conference of the Parties (March/April 1995), 128 nations had ratified the Convention. Parties to the Convention commit to numerous obligations, including commitments to: develop national inventories of anthropogenic emissions using agreed, comparable methodologies’, and to formulate and implement national programs containing measures to mitigate, and to facilitate adaptation to, climate change. Several bilateral and multilateral programs, including the United States Country Studies Program (U.S. CSP) and the United Nations Environment Programme/Global Environment Facility Country Case Studies Project (UNEP), have been established to provide technical and financial assistance to developing countries and countries with economies in transition in meeting their commitments under the Convention.

The determination of Ir and Pt in rhodium neutron monitors was investigated via192Ir and199Au after neutron activation, via191Pt and194Au−196Au after proton activation. Ir was determined by instrumental NAA. A chemical separation of gold, with a yield measurement method by a radioactive tracer, was developed for platinum determination after neutron or proton irradiation.

In this study, we report sulfate content measurements of eighty snow samples collected in East Antarctica. Stringent contamination free techniques were used both for sampling and analysis (ionometric titration with a lead selective electrode after preconcentration). Sulfate concentrations (range: 50–100.10−9 g g−1, accuracy ±10%) do not show large variations along a 1100 km coast interior axis, if we except a narrow coastal area. The analysis of well dated snow samples (time range: 1950–1975) collected at South Pole Station and Dome C (124°E, 75°S) suggest a main marine contribution for the sulfate content, to which are added sporadic stratospheric injections linked with major volcanic events, such as Mt. Agung (1963), whose eruption is clearly recorded. There is no evident anthropogenic contribution to the measured values.

A simplified calculation model of the recoil and irradiation enhanced diffusion which occur in neutron activation analysis of metals is proposed. Under usual irradiation conditions, the recoil does not exceed 0.01 μm for n, γ reactions and 2 μm for other reactions; the diffusion does not exceed 1 μm. Examples, in which deep impurity diffusion leading to important analytical errors was put forward, are discussed through this calculation model. In most cases, the observed phenomena are not related to diffusion but to other causes such as unefficient etching of the sample surface.