B.Dasaram1*, M.Satyanarayanan1, V.Sudarshan2 and A. Keshav Krishna1
1National Geophysical Research Institute (Council of Scientific & Industrial Research) Uppal Road, Hyderabad-500007
2Department of Applied Geochemistry, Osmania University, Hyderabad-500007 *E-mail: email@example.com
Toxic trace metals concentrations in soil exert a decisive impact on soil quality and its use in food production particularly in an industrial area. An attempt is made here to study toxic metals such as Cr, Cu, Ni, Pb, Zn, including Ba, Co and V in representative soil samples from Patancheru industrial area near Hyderabad, Andhra Pradesh. It is a known polluted area and is one of the most contaminated regions where about 260 small and large-scale manufacturers of pharmaceuticals, paints, pesticides, chemicals, steel and metallic products have been functioning for over several decades. Toxic trace metal geochemical studies were carried out in fifteen representative soil samples collected from residential and agricultural area, to understand the spatial distribution and to assess the level of contamination on the basis of index of geoaccummulation, enrichment factor, contamination factor and degree of contamination. The various indices show that residential soils are contaminated with Cr, Ni and Pb (Cu to some extent). The agricultural area, although were invariably enriched in these toxic metals, showed comparatively less contamination possibly due to uptake by plants.
Key words Toxic trace metal, contamination, Patancheru, Industrial area 1. Introduction
The unchecked industrial and human activities have contributed toxic trace metals from anthropogenic sources into surface and subsurface soils when compared to those contributed from geogenic processes . Higher economic growth, rapid industrialization and indiscriminate disposal of waste materials without adequate knowledge of toxic pollutants and their control, are responsible for increasing soil environmental hazards at an alarming rate. Hyderabad is the fifth largest city in India with its population touching five millions and covering an area of 1574 sq. km. Many industrial zones like Patancheru, Nacharam, Cherlapalli, Jeedimetla, Balanagar and Saroornagar, which were once located at the outskirts, have now become integral parts of the city threatening the environment. Patancheru industrial development area is one such industrial zone, which has been identified as one of the most contaminated areas by the various pollution control boards (PCBs) and frequently referred to as an area of ecological disaster [2-4].
Earlier studies were carried out to decipher concentration of several toxic trace metals in soil/water in Patancheru [2,3,5-11]. In order to assess the level of contamination an attempt is made to study the impact of toxic trace metals in soil on the basis of (i) Index of geoaccummulation (assessment by comparing current and crustal concentration) (ii) Enrichment factor (standardization of trace metals against a reference element) (iii) Contamination factor (assessment of soil contamination through a reference element in comparison with crustal level) and (iv) Degree of contamination (sum of all elements examined).
2. Study area
The study area in Patancheru (17o13'N - 17o35'N; 78o12.5'E - 78o17.5'E), located north of Hyderabad, covers an area of about 124 sq. km., and forms part of the catchments of Nakkavagu stream, a tributary of the Manjira River, which is one of the main sources of drinking water for Hyderabad city. It can be seen from the drainage map (Fig.1) that many of the rivulets tend to flow towards Nakkavagu stream thereby contributing the load of toxic trace metals into the stream . About 260 industries are situated in this area, producing chemicals, pharmaceuticals, paints, pesticides, steel products and different types of...