Necat Agca - Academia.edu (original) (raw)
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Papers by Necat Agca
Environmental Monitoring and Assessment, 2006
Spatial and seasonal differences in water quality of drainage water and unconfined shallow ground... more Spatial and seasonal differences in water quality of drainage water and unconfined shallow groundwater were related to irrigation in Samandag, a Mediterranean coastal region. Eighteen wells, seven drainage points and Orontes River were monitored bimonthly for one year for analyses of electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR), cations (Na, K, Ca + Mg) and anions (CO 3 , HCO 3 , Cl and SO 4 ). Agricultural irrigation using saline groundwater decreased water quality of Orontes River during the irrigation season (May to September) more than during the non-irrigation season (October to April). Seasonal fluctuations in water quality of shallow groundwater were greater during the irrigation season than the non-irrigation season in the study area. Excessive use of groundwater resulted in a decline in the water table levels in the irrigation season. Water table level rose up to the soil surface in areas where there was a lack of drainage or poor drainage, due to the impact of precipitation in the winter. SAR and pH values of drainage water increased in the irrigation season, while the other properties of drainage water decreased. Irrigation water quality of Orontes River was classified as C 3 S 1 in both seasons. Irrigation water quality of shallow groundwater and drainage water varied from C 2 S 1 to C 4 S 2 in one year. Drainage and well waters were found to be different on yearly basis in terms of Na, SAR ( p < 0.01) and Ca + Mg concentrations ( p < 0.001). Ca + Mg concentrations for both sources were different for all sampling dates ( p < 0.001).
Environmental Monitoring and Assessment, 2011
The purpose of the study was to investigate the total and bio-available contents of heavy metals ... more The purpose of the study was to investigate the total and bio-available contents of heavy metals (Cd, Co, Ni, and Pb) and to determine their spatial variability in the Amik Plain, Turkey. Samples of surface and subsurface soil were collected at 132 sites in the research area. All of the total metal concentrations except Ni were considerably lower than their maximum allowable concentrations. Mean available Pb concentrations at both depths were above the permissible limits, while the other metal concentrations were within the proposed limits. Semivariograms of all the total metal contents, pH, and available Ni and Pb content were best fitted to spherical models, while available Cd and Co contents were best fitted to exponential models. Block kriging was used to interpolate values at unmeasured locations, generating maps of spatial variation for each heavy metal and pH.
Environmental Monitoring and Assessment, 2006
Spatial and seasonal differences in water quality of drainage water and unconfined shallow ground... more Spatial and seasonal differences in water quality of drainage water and unconfined shallow groundwater were related to irrigation in Samandag, a Mediterranean coastal region. Eighteen wells, seven drainage points and Orontes River were monitored bimonthly for one year for analyses of electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR), cations (Na, K, Ca + Mg) and anions (CO 3 , HCO 3 , Cl and SO 4 ). Agricultural irrigation using saline groundwater decreased water quality of Orontes River during the irrigation season (May to September) more than during the non-irrigation season (October to April). Seasonal fluctuations in water quality of shallow groundwater were greater during the irrigation season than the non-irrigation season in the study area. Excessive use of groundwater resulted in a decline in the water table levels in the irrigation season. Water table level rose up to the soil surface in areas where there was a lack of drainage or poor drainage, due to the impact of precipitation in the winter. SAR and pH values of drainage water increased in the irrigation season, while the other properties of drainage water decreased. Irrigation water quality of Orontes River was classified as C 3 S 1 in both seasons. Irrigation water quality of shallow groundwater and drainage water varied from C 2 S 1 to C 4 S 2 in one year. Drainage and well waters were found to be different on yearly basis in terms of Na, SAR ( p < 0.01) and Ca + Mg concentrations ( p < 0.001). Ca + Mg concentrations for both sources were different for all sampling dates ( p < 0.001).
Environmental Monitoring and Assessment, 2011
The purpose of the study was to investigate the total and bio-available contents of heavy metals ... more The purpose of the study was to investigate the total and bio-available contents of heavy metals (Cd, Co, Ni, and Pb) and to determine their spatial variability in the Amik Plain, Turkey. Samples of surface and subsurface soil were collected at 132 sites in the research area. All of the total metal concentrations except Ni were considerably lower than their maximum allowable concentrations. Mean available Pb concentrations at both depths were above the permissible limits, while the other metal concentrations were within the proposed limits. Semivariograms of all the total metal contents, pH, and available Ni and Pb content were best fitted to spherical models, while available Cd and Co contents were best fitted to exponential models. Block kriging was used to interpolate values at unmeasured locations, generating maps of spatial variation for each heavy metal and pH.