Urban Geochemistry (Estonia, China)
Country / Region: Qinhuangdao Area, Hebei Province, Estonia, Tallinn Geochemical survey, mapping
Begin of project: January 1, 1998
End of project: January 1, 2003
Status of project: June 1, 2003
Qinhuangdao Area, Hebei Province of China
In a national geochemical investigation progamme, the Ministry of Land and Resources has documented the composition of near-surface rocks, soils and fluviatile sediments throughout China.
In a study covering the Hebei province in north-east China, jointly prepared by the Institute for Geophysical and Geochemical Exploration Langfang/China and BGR, the database from a complete subsurface analysis programme (approx. 2000 samples covering 7,500 km2) was statistically analysed and critically evaluated. The stream sediments were collected with a sample density of one sample per km2 and analyzed for 39 elements. The topsoils (< 20 mesh fraction) were taken with a density of one sample per 4 km2 and analyzed for 36 elements. The prority was to determine whether the varied geology was primarily responsible for the distribution of the elements and to assess the extent to which the natural state of affairs had changed over the centuries as a result of human impact.
About 152 topsoils were collect in Shanghaiguang at the eastern end of the Great Wall and in Beidaihe, the famous summer resort. These samples were analyzed in the BGR laborities for 43 elements.
To evaluate and interpret the geochemical data, single-element maps, factor maps and maps of the pollution index for various trace elements were prepared.
The concentrations of As, B, Cd, Mo, Pb, Sb, Si, Sn, Ti and Y in stream sediments in the central and nothern parts of study area are lower than the national stream sediment background values, which are mainly of natural origin, i.e., related to the composition of the parent materials. The elevated average values for Al, Co, Cr, Cu, F, Fe, K, Mg, Na, Ni, P, Sr, V, Zn and Th indicate regional mineralizations and metal deposits. The concentrations of Na, Si, Sr and Cl in the soil of the southern and central parts are related to the widespread distribution of sandy soils in the southern part of Qinhuangdao.
Download Poster: Regional and Urban Geochemistry in the Qinhuangdao Area, Hebei Province of China (Zhou & Birke) (PDF, 428 KB)
Tallinn, Estonia
The project supported by the Scientific and Environmental Affairs Division of NATO. Over 1400 soil samples were collected in two campaigns between 1988-1990 and 1996/97. 530 samples were analysed for up 47 parameters (13 major and 34 microelements, low-field magnetic susceptibility) by XRFA and AAS in the BGR. Low-field magnetic susceptibility (K) was measured by Geotysika KLY-2 and Exploranium KT-9 instruments at the University of Leoben.
Statistical analysis and mapping of major and trace elements at the territory of the Tallinn region and of the city were performed and background values and local anomalies of chemical element on the territority were determined.
Comparative analysis of both geochemical data sets for Tallinn region and urban Tallinn in order to investigate the distribution of elements and assess the spatial variation of their content in topsoils in the studied area on a long-term basis was performed using geochemical mapping techniques in conjunction with statistical methods. The geochemical data sets were processed using statistical analysis, correlation and factor analysis (R-mode). Six dominant factors were chosen for every data set for further interpretation. Analysis of factor matrixes permitted to reveal the typical for Tallinn region and city geochemical associations of elements whose accumulation in the soils has a natural origin (Al, Ti, K, Ga, Fe) or is caused by contamination attributed to processes of the pollution in the result of industrial activity (Cu, Pb, Zn, Ni, Mo, Cr, Mn, As). Pollution of soils by P, F, Sr and TOC took place in the result of exploration of phosphorite deposits in the Tallinn suburbs and use of phosphate fertilizers.
The elements Ca and Mg reflect the influence of subsurface pattern carbonate rocks on the soil composition.
Some of the heavy metal anomalies were impressively confirmed by magnetic susceptibility. The heavy metal concentrations in the soils in Tallinn are around three to five times as high as the geochemical background values from the surrounding area.
A repetition of the analysis after seven years revealed some surprising changes. Whilst the concentrations of non-ferrous metals (Cu, Sn, Zn, V, Y) remained unchanged, the contents of other non-ferrous metals (Ni, Pb), steel additives (Cr, Mn) and other elements (As, Ba, Ga) had reduced considerably in the soil.
Download Poster: Urban Geochemistry - Monitoring of Topsoils in Tallinn and its Suburbs, Estonia (Bityukova & Birke) (PDF, 597 KB)