An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban a...An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban agglomerate in Asia. Concentration of both anionic synthetic detergents and organochlorine pesticide resi-dues analysed from 54 and 19 sampling stations covering groundwater and surface water sources respec-tively, are generally found to be within the tolerance limit for human consumption. The concentration of synthetic detergent ranges from 0.084 to 0.425mg/l. Residues of organochlorine pesticides are analysed from different sources like tanks, lakes, rivers and groundwater. Lindane (0.01-0.43μg/l) and DDT (0.03-0.65 μg/l) are the most widely detected pesticide residues. Howerer, the two have not exceeded the limits for drinking anywhere. High value of aldrin and dieldrin (0.9μg/l) is obtained in the river Hugli at Barakpur-Seoraphuli, 20 km north of Kolkata. Likewise high value of Heptachloreis detected in a canal water sample at Palta (0.05 μg/l), a suburban area. Seasonally, the pesticide concentration in surface water is maximum during winter due to their higher application and minimum during monsoon. In groundwater, however, this relationship is reverse due to higher infiltration of surface water during monsoon.展开更多
In the present study,the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different seasons.An area of 594.36 km2(6.75%)and 4.17 km^(2)(0.04%)was affected by surface water...In the present study,the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different seasons.An area of 594.36 km2(6.75%)and 4.17 km^(2)(0.04%)was affected by surface waterlogging during pre and postmonsoon season,respectively.The average annual groundwater level fluctuations were calculated using 18 years(1990-2007)pre and postmonsoon groundwater level data to identify the areas which are under groundwater induced waterlogging conditions.The soil map clearly indicates that salinity and sodicity exhibit the highest severity and occur in areas with shallow groundwater levels.The hydrogeomorphical units mapped using IRS P6 LISS III satellite images are flood plain,alluvial plain,paleochannels,and oxbow lakes.The study revealed that 44.65%areas have very good to excellent groundwater resources.The litholog data clearly indicate an alternating sequence of clay and sand in which deep aquifers made up of coarse sand would be best suited for adequate water supply and good groundwater quality.The integrated study utilizing digital spatial data pertaining to waterlogging,soil salinity,water level fluctuation,and lithological variation proved that planning of any surface and subsurface water resources development activity should be taken up after assessments of said parameters.展开更多
文摘An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban agglomerate in Asia. Concentration of both anionic synthetic detergents and organochlorine pesticide resi-dues analysed from 54 and 19 sampling stations covering groundwater and surface water sources respec-tively, are generally found to be within the tolerance limit for human consumption. The concentration of synthetic detergent ranges from 0.084 to 0.425mg/l. Residues of organochlorine pesticides are analysed from different sources like tanks, lakes, rivers and groundwater. Lindane (0.01-0.43μg/l) and DDT (0.03-0.65 μg/l) are the most widely detected pesticide residues. Howerer, the two have not exceeded the limits for drinking anywhere. High value of aldrin and dieldrin (0.9μg/l) is obtained in the river Hugli at Barakpur-Seoraphuli, 20 km north of Kolkata. Likewise high value of Heptachloreis detected in a canal water sample at Palta (0.05 μg/l), a suburban area. Seasonally, the pesticide concentration in surface water is maximum during winter due to their higher application and minimum during monsoon. In groundwater, however, this relationship is reverse due to higher infiltration of surface water during monsoon.
文摘In the present study,the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different seasons.An area of 594.36 km2(6.75%)and 4.17 km^(2)(0.04%)was affected by surface waterlogging during pre and postmonsoon season,respectively.The average annual groundwater level fluctuations were calculated using 18 years(1990-2007)pre and postmonsoon groundwater level data to identify the areas which are under groundwater induced waterlogging conditions.The soil map clearly indicates that salinity and sodicity exhibit the highest severity and occur in areas with shallow groundwater levels.The hydrogeomorphical units mapped using IRS P6 LISS III satellite images are flood plain,alluvial plain,paleochannels,and oxbow lakes.The study revealed that 44.65%areas have very good to excellent groundwater resources.The litholog data clearly indicate an alternating sequence of clay and sand in which deep aquifers made up of coarse sand would be best suited for adequate water supply and good groundwater quality.The integrated study utilizing digital spatial data pertaining to waterlogging,soil salinity,water level fluctuation,and lithological variation proved that planning of any surface and subsurface water resources development activity should be taken up after assessments of said parameters.
