Mapping of chromium in the greater area of Asopos River basin

Summarization: The greater area of the Asopos river, situated at the Region of Sterea Ellada, north of Athens is a unique case of combined anthropogenic and geogenic origin of chromium contamination. The high concentrations of chromium and hexavalent chromium found at the groundwater system of Asopos have resulted in an increased public concern, since part of the groundwater is used for water abstraction for human consumption and most of it for irrigation purposes. The objective of this work was to organize all available data pertinent to the groundwater flow and chromium transport modeling of the area into maps, using geographical information systems, geotechnical graphics software and geostatistical techniques. The data was collected from various sources such as field campaigns, existing reports, data logs etc. One of the most important parameters that affect chromium transport is the geology of the area, thus a digitized geological map of the main formations encountered in the upper layers of the subsurface of the region was generated. In addition, geological boring logs for a large number of wells were created (using a geotechnical graphics software) and then combined in order to create vertical cross-sections, at various locations in the greater area, that define the geological characteristics of the deeper layers. The combination of the above defines the 3-D representation of the geological stratification of the physical system. Another parameter of interest in the area is the groundwater level and flow direction. In order to create a hydraulic head map of the area, the locations of more than 1000 shallow and deep wells that have been documented in the greater area of the Asopos river basin were defined using GIS software. A kriging technique was then applied to the available data in order to produce hydraulic head contours and consequently define the general groundwater flow direction. The same technique was applied for the generation of chromium concentration contours that provide an indication of the most problematic locations as well as a general chromium background level in the greater area.Παρουσιάστηκε στο: 13th International Conference on Environmental Science and Technolog