The Forum of European Geological Surveys Geochemistry Task Group 1994-1996 inventory

The Forum of European Geological Surveys (FOREGS) includes representatives from 33 European countries and is responsible for co-ordinating Geological Survey activities in Europe. The FOREGS Geochemistry Task Group was established in 1994 to develop a strategy for the preparation of European geochemical maps following the recommendations of the International Geological Correlation Programme (IGCP) Project 259 ‘International Geochemical Mapping’ (now the International Union of Geological Sciences (IUGS) /International Association of Geochemistry and Cosmochemistry (IAGC) Working Group on Global Geochemical Baselines). The FOREGS geochemistry programme is aimed at preparing a standardised European geochemical baseline to IGCP-259 standards. The principal aims of this dataset will be for environmental purposes, as a baseline for the assessment of the extent and distribution of contaminated land in the context of variations in the natural geochemical background, but it will also have applications in resource assessment and for the development of policy for the sustainable management of metalliferous mineral and other resources. The first phase of the programme was the compilation of an inventory of geochemical data based on the results of a questionnaire completed by Geological Surveys and related organisations throughout the FOREGS community. The results show that the sample types which have been used most extensively are stream sediment (26% coverage), surface water (19% coverage) and soil (11% coverage). Stream sediments have been collected using a narrow range of mesh sizes (< 150–< 200 μm), but soil samples have been collected according to two different conventions: some surveys used a similar mesh size range to that used for stream sediments while others employed the < 1000 or < 2000 μm fractions traditionally used by soil surveys. Sample densities range from 1 sample per 0.5 km2 to 1 per 3500 km2. Various analytical methods have been used, but most of the available data have been calibrated using international reference materials, and data for the most important of the potentially harmful elements (PHEs) are available for most datasets. Systematic radiometric data are available for only a small proportion of Europe, a situation which compares very unfavourably with that in Australia, North America, the former Soviet Union and many developing countries. Recommendations are made for increasing the compatibility of geochemical methods between national geochemical surveys as a basis for the preparation of a series of European geochemical maps. The next stage of the FOREGS Geochemistry Task Group will be the collection of the Global Reference Network of samples against which to standardise national datasets according to the methods recommended in the final report of the IGCP 259 programme

Cartografía geoquímica multielemental en sedimentos de corriente en un contexto de arco isla volcánico. Aplicación al análisis de potencialidad metalogénica en un area de la República Dominicana

Este estudio presenta los principales resultados y conclusiones de la exploración y cartografía geoquímica multielemental llevada a cabo, a partir de muestras de sedimentos de arroyo, en el sector de Bonao-Constanza de la Cordillera Central de la República Dominicana. En el área estudiada, de 3.800 km2, fueron recogidas 684 muestras, con una densidad de muestreo de 1 muestra / 5 km2, en las que se analizaron 48 elementos químicos por técnicas de ICPAES y Activación Neutrónica. Esta zona, situada en el ámbito del arco isla de borde de la placa caribeña, contiene importantes mineralizaciones de carácter epitermal y volcanosedimentario y posee un gran potencial de nuevas mineralizaciones. Dada la complejidad geológica y los fenómenos superimpuestos de alteración hidrotermal, la geoquímica multielemental permite, a través del análisis de las pautas de distribución espacial de los elementos y de las asociaciones geoquímicas, una definición más razonada de áreas anómalas, su valoración, y un conocimiento de su posible significado en relación con el contexto petrogenético, geológico y geoquímico en el que se hallan. La información geoquímica de los materiales superficiales, permite, de acuerdo con las tendencias generales de la cartografía geoquímica, extraer conclusiones que son de aplicación e interés para el conocimiento geológico y ambiental del territorio, además de para la exploración minera.The main results and conclusions of the multielemental geochemical mapping on stream sediments carried out in the Bonao-Constanza area, Cordillera Central, Dominican Republic are presented in this paper. The studied area covers 3800 km2 . The sampling density applied was 1 sample / 5 km2. A total of 684 samples were taken and 48 elements were analysed by Neutron Activation and ICPAES techniques. The area, located in the island arc of the Caribbean plate, contains important epithermal and volcanosedimentary mineralizations and has a huge potential for blind deposits. Due to the complex geology and the superimposed hydrothermal alterations, the multielemental geochemistry allows, through the analysis of patterns of spatial distribution of the elements and their geochemical associations, a better definition of anomalous zones and their assessment and meaning in relationship with their petrogenetic, geological and geochemical context. The geochemical datasets of the superficial materials allow, according with the general trends of the geochemical exploration and mapping, to get applicable and interesting conclusions for the geological, environmental and mineral exploration knowledge

Cartografía geoquímica multielemental en sedimentos de corriente en un contexto de arco isla volcánico. Aplicación al análisis de potencialidad metalogénica en un area de la República Dominicana

The main results and conclusions of the multielemental geochemical mapping on stream sediments carried out in the Bonao-Constanza area, Cordillera Central, Dominican Republic are presented in this paper. The studied area covers 3800 km2 . The sampling density applied was 1 sample / 5 km2. A total of 684 samples were taken and 48 elements were analysed by Neutron Activation and ICPAES techniques. The area, located in the island arc of the Caribbean plate, contains important epithermal and volcanosedimentary mineralizations and has a huge potential for blind deposits. Due to the complex geology and the superimposed hydrothermal alterations, the multielemental geochemistry allows, through the analysis of patterns of spatial distribution of the elements and their geochemical associations, a better definition of anomalous zones and their assessment and meaning in relationship with their petrogenetic, geological and geochemical context. The geochemical datasets of the superficial materials allow, according with the general trends of the geochemical exploration and mapping, to get applicable and interesting conclusions for the geological, environmental and mineral exploration knowledge

Evaluation of trace elements mobility from soils to sediments between the Iberian pyrite belt and the Atlantic Ocean

An environmental study was conducted in 193 stream sediments and 355 soil samples collected in the lower section of Guadiana River Basin to evaluate the trace elements transfer from one compartment into another. The objective was to evaluate the dispersion of Pb, Cu, Zn and other chemical elements resulting from upstream mines into the lower N-S sector of the Guadiana River Basin to the Atlantic Ocean. The area partly includes the Iberian Pyrite Belt, a known volcanogenic massive sulphide (VMS) province with important mining activity history. Median concentrations of the elements Cu, Pb, Zn, Al, As, Ba, Br, Ca, Mg, Mn and Na are generally higher in the studied sediments than in soils. Soils are normally acidic and mobility of elements is in these conditions higher. When the relations between upstream soils and downstream sediments were established, median values were higher in the upstream soils only for elements such as Co, Ni, K, Pb, Mn and Ti, probably the less mobile, and the Cu, Zn, Al, As, Ba, Br, Ca, Cr, Fe, Mg and Na have highest concentrations in the downstream sediments. Lead was considered the less mobile element and Zn the highly mobile of the base metals in the mining area of the lower Guadiana River. Dispersion of the metals, considering the studied soil and sediment samples is partially restricted to the mining areas or downstream sediments but close to the mine sources, where ore tailings and acid waters occur. Near the mouth, concentrations of As, Cu, Pb and Zn increase in relation with mining and other pollution sources. Interaction with salt water forces chemical elements precipitation from water and subsequent increase of their concentration in sediments. This may be the reason for the increase of those chemical elements concentrations in the sediment

URBAN GEOCHEMICAL STUDIES IN EUROPE

Urban soil is generally contaminated to a variable degree depending on its proximity to contamination sources. Traffic is one of the main sources of urban contamination; lead (Pb) from the use of leaded petrol, zinc (Zn) and cadmium (Cd) from tyre wear, antimony (Sb) from break pads, and the platinum group Nelements (PGEs) from the wear of catalytic converters, are some typical elements that often reach high concentrations in the urban environment. Lead was also a key ingredient in white paint, and in towns with a high proportion of white wooden houses very high concentrations were found in soil. Crematoria can or have emitted mercury (Hg). Coal and heavy oil fired municipal power and heating stations emit sulphur (S), silver (Ag), vanadium (V), bromine (Br) and barium (Ba). The use of impregnated wood may have resulted in high concentrations of arsenic (As), especially in kindergartens (nursery schools) and playgrounds. Building materials (plaster and paint) may also contain high concentrations of organic contaminants, especially polychlorinated biphenyls (PCBs), which again end up in urban soil. Coal and wood burning, the use of diesel fuel, and the production of coke, all lead to the emission of polycyclic aromatic hydrocarbons (PAHs). There exist countless other sources of local contamination in towns, and there is thus every reason to be concerned about the quality of the urban environment, and the suitability of soil for sensitive land uses, such as schools, playgrounds, parks and vegetable gardens. Contaminated urban soil may contaminate indoor dust and, therefore, to an increased human exposure to toxic chemicals. Consequently, the distribution of toxic contaminants in urban soil needs to be documented and known by city administration to avoid costly mistakes in land use planning, and further spreading of highly contaminated materials. The EuroGeoSurveys ‘Geochemistry’ Expert Group during the compilation of a proposal to the Directors for a European wide urban geochemistry project, using a harmonised sampling and analytical methodology, it discovered that many urban geochemical studies have been performed in Europe by National Geological Surveys, which are not known to the wider geoscientific community. Since, the results of these studies are directly related to our quality of life, the EuroGeoSurveys ‘Geo-chemistry’ Expert Group decided to publish at least one case study from each country in a book,which will be available in the second half of 2010. A concise description of some of these studies will be given in this paper

Sources, background and enrichment of lead and other elements: Lower Guadiana River

The lower sector of the Guadiana River Basin, located in southern Portugal and Spain, hosts soils and plants with elevated Pb, Cu and As near former and current mining sites. Two geogenic and two anthropogenic sources of Pb were identified where elevated concentrations are mostly related to the occurrence of sulphide-rich ore deposits, Volcanic Sedimentary formations and mining. These were generally reflected by the multiple regression analysis (MRA) and confirmed by isotope determinations. Nevertheless, caution was needed in interpreting statistical and isotopic results; therefore the combination of both techniques was important. Elements, such as Ca, Na, Cu and As, show enrichment in soil developed on shale, sandstone and conglomerate of Upper Devonian age belonging to the Phyllite-Quartzite Group. Lead exhibits an enrichment in soil developed on felsic volcanic rocks from the Volcanic Sedimentary Complex (VSC) of Upper Devonian-Lower Carboniferous age, which has been identified by the relationship between topsoil median values of different lithologies and grand subsoil median values. In the same soil, Fe, As, Co, Ni and Cr are depleted. Translocation of Pb to the aerial parts of plants is insignificant in all three plant species studied and analysed (Cistus ladanifer L., Thymus vulgaris, Lavandula luisieri). High Pb concentrations in soil, where Cistus ladanifer L. developed, the only representative number of species analysed, do not correspond generally to elevated Pb contents in plants, except near mine sites, where lower pH of soil, increases Pb bioavailability. The different statistical methodologies combined with Pb isotopic studies were successfully applied in the identification of Pb sources in soil and Cistus ladanifer L. plant of the Lower sector of Guadiana River basin. Therefore, rocks, mineralisations, subsoil, topsoil and plant processes were successfully integrated to understand the migration of Pb into the food chai

The FOREGS Geochemistry Task Group 1994-1996

The Forum of European Geological Surveys (FOREGS) includes geological surveys from 33 European countries and is responsible for co-ordinating geological survey activities in Europe. The FOREGS Geochemistry Task Group was established in 1994 as part of the programme, to supervise European geochemical mapping policy following the recommendations of IGCP Project 259 ‘International Geochemical Mapping’. The task group comprises representatives from five countries charged initially with the compilation of an inventory of geochemical data within FOREGS countries

Forum of European Geological Surveys Geochemistry Task Group 1994-1996 Report

Europe has a long history of mining, industrialisation, intensive agriculture/forestry and urbanisation. It remains one of the most densely populated and utilised land areas on earth. These factors have led to interrelated problems of land degrada¬tion and contamination which affect both the land and the coastal zone. Deficiency conditions in crops, agricultural animals and possibly man are increasing, partly as a result of land degradation. Redevelopment of contaminated land is becoming increasin¬gly difficult because of legislative and fiscal controls. This is despite the need to reutilise "brown field" sites rather than extend develop¬ment into "green field" areas.Throughout Europe public concern about the environment is growing. In response, national governments and the European Union (EU) are attempting to develop policies, legislation and infrastructure, such as the European Environment Agency (EEA). Attempts are also being made to establish "Safe Levels" of Potentially Harmful Elements and Species (PHES), but these are often based on limited and/or inade¬quate informati-on. The available data on environmental geochemical baselines and radioactivity are not systematic in coverage or quality and, therefore, are not of the standard required to quantify the distribution of PHES at the European scale as a basis for policy-making and monitoring future change to the environment