Arohi DIXIT, Kirori Mal College, Delhi University, India
Siddaiah N. SIVA, Jawaharlal Nehru University, India
Rapid developmental activities in urban cities have resulted in conversion of a large part of agricultural and rural land into highly degraded urban lands. Soil characterisation is the most appropriate strategy in understanding the extent and sources of land degradation. In this study, surface soils of Gurugram (a mega urban city) falling in different land use areas were comprehensively studied for their chemical properties and heavy metal distribution, to identify: sources, variations, spatial distributions, and their impacts on human health and ecosystem. The soils of Gurugram city are sandy (85- 90 wt. %), alkaline (pH = 6.53-8.84) with variable salinity (EC = 20 to 384 µS/cm). The soils in urban areas (industrial, commercial and residential) are enriched in heavy metals particularly Cu, Zn and Pb compared to background. Among the heavy metals, Zn (39.72-231.80 mg/kg) and Cr (56.50-139.16 mg/kg) are the most abundant. High Zn and Pb (12.46-63.56 mg/kg) concentrations are observed in commercial sites. The observed concentrations of heavy metals in the soils of Gurugram irrespective of the land use are below the average concentrations reported for world soils except Cr and Zn that are above the world average values. Since all the sites belong to same geographical locality, the variations in observed abundances are presumably anthropogenic. The calculated values of enrichment factor (EF), pollution load index (PLI) and geo-accumulation index (Igeo) suggests that the soils of Gurugram are unpolluted to moderately polluted. PCA and correlation further confirms that the sources of these metals are both natural and anthropogenic with Co, Ni and Cr mainly from natural sources, while Cu, Pb and Zn mainly from anthropogenic sources. Some hotspots of metals were also observed in spatial distribution maps which need more attention. Hence, strategic monitoring and timely action is highly recommended for the hotspots of degraded land created in the city.
Mots clés : Urbanisation|Land use pattern |Heavy metals |Soil pollution indices|Spatial distribution
A103442AD