The Ludhiana Township has a dubious distinction of being one of the most polluted human settlements in the country. The area falls in the tropical semiarid hot climate zone characterized by dryness, except a brief rainy (Monsoon) season (July to September), a very hot summer and bracing winter. It is located near to a great Himalayan River, Satluj whose abandoned palaeochannel flows through the heart of the City with a common local name ’Budah Nala’ as a perennial stream fed by surface water and groundwater. It serves as a sink for industrial effluents and is responsible for most of the pollution of groundwater of the area.
The soils of the research area have been studied for their morphological and mineralogical properties... The morphological characters have been used for identification, classification and interpretation of different soils and help in differentiating soil horizons in a soil profile. Soil mineralogy has been studied with help of microscope and X-Ray diffraction. Textural analysis of soil is also carried out to determine the percent of sand, silt and clay. The primary minerals identified under the microscope include quartz, feldspar, rock fragments, muscovite and biotite. These are packed weakly to moderately oriented clay matrix. The clay minerals constituting the soils of the research area include kaolinite, illite, vermiculite and montmorllonite, though they are not uniformly distributed in different soil samples from different areas. Illite, however, seems to be most dominant clay mineral. On the basis of texture, six classes of soils are defined viz. sand, loamy-sand, sandy-loam, loam and silty-clay-loam.
The mineralogy and texture in the soils plays an important role in the mobility and distribution of pollutants in the soil zone. The amount and type of clay minerals determines the extent up to which the adsorption of pollutants is possible and play an important role in the movement of pollutants through the soil-water interface. Thus the soil acts as a sink for pollutants before they enter the groundwater regime.
Depending upon the groundwater conditions and the type of soil cover, the quality of groundwater in the research area has deteriorated to different levels in different zones identified as Industrial Zone, Mixed Use Zone and Residential Zone. A contamination risk zone map has been prepared on the basis of soil- groundwater processes possibly taking place during the infiltration of pollutants through soil-water interface.