Methodologies
To achieve the tasks' objectives geomorphological and socio-economic information concerning the lagoon physical geosystem and bio-geochemical information concerning the soils, sediments and water is required.
For the geochemical, organochemical, mineralogical and isotopic analyses the following methodology will be planned :

• " Sampling of 20 soil profiles in the study areas and selected according to the surface to be studied. Each profile will be sampled in two levels at different depths, the parent rock being also sampled in some instances ( 50 samples in total).
• " On samples from the two shallower levels of soils, measurement of total content of trace elements and heavy metals (As, Cd, Cu, Pb, Zn, Hg, Cr) by inductively coupled plasma spectrometry (ICP-AES), except for mercury which will be measured by cold vapour atomic absorption spectrometry.
• " On 10 potentially polluted points of the study areas, as well as on highly polluted samples from the soils and sediments of the lagoons the following will be analysed: a) mineralogical study by X-ray diffraction (DRX); b) speciation, bioavailability and toxic grade testing; and c) calculation of some determinant factors for the presence and mobility of pollutant elements (pH, texture, organic matter, exchange capacity, determination of carbonates, salinity, iron oxides and hydroxides) on selected samples (20 samples). The purpose is to determine the manner in which contaminants are retained in soils and to evaluate the potential for lagoon contamination
• " If results exceed the maximum permissible values for recommended investigation, an appraisal of metals that can be extracted by water (Norma DIN 38 414-4) and by EDTA should be made. Moreover, those samples with values exceeding the control levels will in addition to the methods mentioned above be considered under the Tessier Sequential Method.

The methodology proposed for the geochemical research of selected areas has previously been tested with satisfactory results by the partners from the EU countries while working on similar problems during the last five years. This experience has shown that it is recommended to carry out field surveys in order to collect environmental data systematically, and to sample potentially polluted soils and sediments for further studies on bioavailability and toxicity. Density and depth of soil sampling, as well as preliminary processing of samples and other protocols, will follow the methodology proposed by the partners from the EU countries.

Read more about the interaction between Clay Minerals and Heavy Metals; and on the use of Mossbauer spectroscopy.

The use of GIS as a spatial, analytical tool, will permit the integration and the analysis of a huge volume of spatial data (including hydrological, geomorphological, as well as landuse and relevant socio-economic data) gathered by the multi-disciplinary teams through conventional field surveys as well as through the use of remote sensing applications. The use of ocean colour data obtained through ERS 1&2 and ENVISAT for lagoon management will be researched. Knowledge of the sea colour can be converted into a measurement of chlorophyll pigment concentration, suspended sediment concentration and of aerosol loads over the marine domain. COLASU will be focusing on one of the four broad domains of applications of ocean-colour data namely that for the management of coastal zones. The combined use of data derived from remote sensing and field surveys will allow to project regional development scenarios. Moreover, the information derived from remote sensing interpretation will be ground-truthed in Tunisia and in Morocco and will also be correlated with field data collected by the other partners etc. In this regard, it is possible that through the use of remote sensing, information is picked up that may not have been picked up through conventional surveys.

By including also the socio-economic data, the GIS will become an even more effective decision support tool. In particular, COLASU will explore the possibility to couple the GIS with the Life Cycle Assessment (LCA) in order to reconcile the spatial scales of process/data at lagoon level.

The LCA is a standard tool to assess the use of resources and the potential environmental impacts associated with a process or a product and a tool to provide information useful for decision making. Generally LCA takes into account environmental impact at global level (e.g. greenhouse effect). In this research program the focus is on a local scale and on a local impact of human activity. The LCA methodology is conducted in four stages (see Fig.1):

• defining goals and scope of the study: This permits to define the problem with precision and to verify that LCA is a suitable tool to deal with it. The private enterprise, the public authority may wish to use an LCA to come to a informed decision.
• inventory analysis: indexes and quantifies materials and input and output energy flows of the defined anthropogenic system.
• Impact assessment: evaluates the extent of potential environmental impacts on the basis of the results of the life cycle inventory analysis. This assessment includes three principal stages: Impact classification; Impact characterisation and Global assessment of impacts. Here we consider the economical aspect of the study and the impact cost.
• Interpretation: This stage must help the decision-maker to weigh decisions between environmental, technical and economical constraints. 

Fig.1. Stages of Life Cycle Analysis, from NF X 30-300 (April 1996)

With respect to the risk analysis in the LCA, reference is made "Application of uncertainty and variability in LCA" by Mark A.J. Huijbregts, in Int'l Journal LCA (1998) 273-280. The paper presents an overview of available tools to address uncertainty and variability in LCAs.

Read more on Life Cycle Assessment, its application in the Colasu research project and a concise bibliographic references inventory.