The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
K Voudouris - One of the best experts on this subject based on the ideXlab platform.
-
management and research strategies of karst aquifers in greece literature overview and exemplification based on hydrodynamic modelling and vulnerability assessment of a strategic karst aquifer
Science of The Total Environment, 2018Co-Authors: Nerantzis Kazakis, Chloé Ollivier, Konstantinos Chalikakis, Naomi Mazzilli, Antonios Manakos, K VoudourisAbstract:Karst aquifers are valuable water resources in terms of quantity and quality, hence, their protection and rational management is of utmost importance to sustain water supply. An overview of research articles regarding Karst aquifers in Greece was obtained revealing that progressively the initial simple statistical analysis was replaced from advanced tools but rarely coupled. Additionally, a combined approach including the concept of groundwater vulnerability and Pollution Risk in conjunction with statistical and hydrodynamic analysis was performed in the complex karst aquifer of Damasi-Titanos in Thessaly Central Greece. The karst aquifer discharges via three springs and it is in dynamic interaction with one of the two rivers that cross the system. The water demands of the area are mainly met with groundwater from the karst aquifer rendering its protection fundamental priority for the sustainability of the area. The hydrodynamic analysis of the karst system was performed by pairing statistical techniques and KarstMod. The analysis revealed a high correlation between the springs that highlights the karstification maturity of the aquifer. Additionally, spring discharge is mainly controlled by the percolation of River Titarisios rather than precipitation. Following the hydrodynamic analysis, the PaPRIKa method was applied and validated using sensitivity analysis in order to assess the intrinsic vulnerability. The vulnerability and hazard maps were combined to produce the Pollution Risk map of the karst aquifer. The majority of the karst aquifer is characterized by high to very high vulnerability as well as Pollution Risk. The case study and the obtained overview revealed that a holistic approach can provide mutually supported results increasing their reliability. In this base, a four-step road map including hydrogeological observation, statistical analysis, modelling and vulnerability assessment is suggested in order to obtain the sustainable exploration and integrated management of karst aquifers in Greece.
-
a modified sintacs method for groundwater vulnerability and Pollution Risk assessment in highly anthropized regions based on no3 and so42 concentrations
Science of The Total Environment, 2017Co-Authors: Gianluigi Busico, Nerantzis Kazakis, K Voudouris, Nicolo Colombani, Micol Mastrocicco, Dario TedescoAbstract:Abstract Groundwater vulnerability and Risk assessment are worldwide tools in supporting groundwater protection and land planning. In this study, we used three of these different methodologies applied to the Campanian Plain located in southern Italy: SINTACS, AVI and LOS. However, their capability to describe the observed chemical Pollution of the area has resulted quite poor. For such a reason, a modified SINTACS method has been then implemented in the area in order to get a more reliable view of groundwater vulnerability. NO3− and SO42 − from more than 400 monitoring wells were used for specific vulnerability assessment. Land use was chosen as key parameter to infer the Risk of groundwater Pollution in our area. The new methodology seems to show a higher correlation with observed NO3− concentrations and a more reliable identification of aquifer's Pollution hot spots. The main sources of NO3− were found in sub-urban areas, where vulnerability and Risk are higher than in other areas. Otherwise due to reducing conditions triggered by the presence of elevated sedimentary organic matter and peat, concentrations below agricultural areas were lower than in sub-urban areas. The SO42 − specific vulnerability map showed a positive correlation with observed concentrations, due to geogenic and anthropogenic SO42 − sources present in the area. The combination of both NO3− and SO42 − derived Risk maps becomes essential to improve the conceptual model of aquifer Pollution in this severely anthropized area. The application of this new and original approach shed light on the strengths and weaknesses of each of the described previous methods and clearly showed how anthropogenic activities have to be taken into account in the assessment process.
-
groundwater vulnerability and Pollution Risk assessment with disparate models in karstic porous and fissured rock aquifers using remote sensing techniques and gis in anthemountas basin greece
Environmental Earth Sciences, 2015Co-Authors: Nerantzis Kazakis, Dimitrios Oikonomidis, K VoudourisAbstract:Disparate methods of intrinsic groundwater vulnerability and remote sensing were applied in Anthemountas river basin (North Greece), covering an area of 374 km2. Three types of aquifers are present within the basin: porous, karstic, and aquifers of fissured rocks. Vulnerability and Risk Pollution maps were produced using the DRASTIC, EPIK, AVI, and DRASTIC-FM methods in a Geographic information system (GIS) context, and the results were compared and evaluated. The methods used different numbers of parameters with different weightings and produced relatively different results. The original DRASTIC method underestimates the vulnerability degrees in fissured rock aquifers, while in porous aquifers the discretization is poor, in contrast with the AVI method which gives more satisfactory results. The vulnerability of the fissured rock aquifer as estimated by the DRASTIC-FM method shows significant differences compared to the original DRASTIC method. Groundwater Pollution Risk is strongly dependant on vulnerability, and consequently the use of specialized vulnerability methods provides representative and more accurate results.
-
Groundwater vulnerability and Pollution Risk assessment of porous aquifers to nitrate: Modifying the DRASTIC method using quantitative parameters
Journal of Hydrology, 2015Co-Authors: Nerantzis Kazakis, K VoudourisAbstract:In the present study the DRASTIC method was modified to estimate vulnerability and Pollution Risk of porous aquifers to nitrate. The qualitative parameters of aquifer type, soil and impact of the vadose zone were replaced with the quantitative parameters of aquifer thickness, nitrogen losses from soil and hydraulic resistance. Nitrogen losses from soil were estimated based on climatic, soil and topographic data using indices produced by the GLEAMS model. Additionally, the class range of each parameter and the final index were modified using nitrate concentration correlation with four grading methods (natural breaks, equal interval, quantile and geometrical intervals). For this reason, seventy-seven (77) groundwater samples were collected and analyzed for nitrate. Land uses were added to estimate the Pollution Risk to nitrates. The two new methods, DRASTIC-PA and DRASTIC-PAN, were then applied in the porous aquifer of Anthemountas basin together with the initial versions of DRASTIC and the LOSN-PN index. The two modified methods displayed the highest correlations with nitrate concentrations. The two new methods provided higher discretisation of the vulnerability and Pollution Risk, whereas the high variance of the (ANOVA) F statistic confirmed the increase of the average concentrations of NO3−, increasing from low to high between the vulnerability and Pollution Risk classes. The importance of the parameters of hydraulic resistance of the vadose zone, aquifer thickness and land use was confirmed by single-parameter sensitivity analysis.
Nerantzis Kazakis - One of the best experts on this subject based on the ideXlab platform.
-
management and research strategies of karst aquifers in greece literature overview and exemplification based on hydrodynamic modelling and vulnerability assessment of a strategic karst aquifer
Science of The Total Environment, 2018Co-Authors: Nerantzis Kazakis, Chloé Ollivier, Konstantinos Chalikakis, Naomi Mazzilli, Antonios Manakos, K VoudourisAbstract:Karst aquifers are valuable water resources in terms of quantity and quality, hence, their protection and rational management is of utmost importance to sustain water supply. An overview of research articles regarding Karst aquifers in Greece was obtained revealing that progressively the initial simple statistical analysis was replaced from advanced tools but rarely coupled. Additionally, a combined approach including the concept of groundwater vulnerability and Pollution Risk in conjunction with statistical and hydrodynamic analysis was performed in the complex karst aquifer of Damasi-Titanos in Thessaly Central Greece. The karst aquifer discharges via three springs and it is in dynamic interaction with one of the two rivers that cross the system. The water demands of the area are mainly met with groundwater from the karst aquifer rendering its protection fundamental priority for the sustainability of the area. The hydrodynamic analysis of the karst system was performed by pairing statistical techniques and KarstMod. The analysis revealed a high correlation between the springs that highlights the karstification maturity of the aquifer. Additionally, spring discharge is mainly controlled by the percolation of River Titarisios rather than precipitation. Following the hydrodynamic analysis, the PaPRIKa method was applied and validated using sensitivity analysis in order to assess the intrinsic vulnerability. The vulnerability and hazard maps were combined to produce the Pollution Risk map of the karst aquifer. The majority of the karst aquifer is characterized by high to very high vulnerability as well as Pollution Risk. The case study and the obtained overview revealed that a holistic approach can provide mutually supported results increasing their reliability. In this base, a four-step road map including hydrogeological observation, statistical analysis, modelling and vulnerability assessment is suggested in order to obtain the sustainable exploration and integrated management of karst aquifers in Greece.
-
a modified sintacs method for groundwater vulnerability and Pollution Risk assessment in highly anthropized regions based on no3 and so42 concentrations
Science of The Total Environment, 2017Co-Authors: Gianluigi Busico, Nerantzis Kazakis, K Voudouris, Nicolo Colombani, Micol Mastrocicco, Dario TedescoAbstract:Abstract Groundwater vulnerability and Risk assessment are worldwide tools in supporting groundwater protection and land planning. In this study, we used three of these different methodologies applied to the Campanian Plain located in southern Italy: SINTACS, AVI and LOS. However, their capability to describe the observed chemical Pollution of the area has resulted quite poor. For such a reason, a modified SINTACS method has been then implemented in the area in order to get a more reliable view of groundwater vulnerability. NO3− and SO42 − from more than 400 monitoring wells were used for specific vulnerability assessment. Land use was chosen as key parameter to infer the Risk of groundwater Pollution in our area. The new methodology seems to show a higher correlation with observed NO3− concentrations and a more reliable identification of aquifer's Pollution hot spots. The main sources of NO3− were found in sub-urban areas, where vulnerability and Risk are higher than in other areas. Otherwise due to reducing conditions triggered by the presence of elevated sedimentary organic matter and peat, concentrations below agricultural areas were lower than in sub-urban areas. The SO42 − specific vulnerability map showed a positive correlation with observed concentrations, due to geogenic and anthropogenic SO42 − sources present in the area. The combination of both NO3− and SO42 − derived Risk maps becomes essential to improve the conceptual model of aquifer Pollution in this severely anthropized area. The application of this new and original approach shed light on the strengths and weaknesses of each of the described previous methods and clearly showed how anthropogenic activities have to be taken into account in the assessment process.
-
groundwater vulnerability and Pollution Risk assessment with disparate models in karstic porous and fissured rock aquifers using remote sensing techniques and gis in anthemountas basin greece
Environmental Earth Sciences, 2015Co-Authors: Nerantzis Kazakis, Dimitrios Oikonomidis, K VoudourisAbstract:Disparate methods of intrinsic groundwater vulnerability and remote sensing were applied in Anthemountas river basin (North Greece), covering an area of 374 km2. Three types of aquifers are present within the basin: porous, karstic, and aquifers of fissured rocks. Vulnerability and Risk Pollution maps were produced using the DRASTIC, EPIK, AVI, and DRASTIC-FM methods in a Geographic information system (GIS) context, and the results were compared and evaluated. The methods used different numbers of parameters with different weightings and produced relatively different results. The original DRASTIC method underestimates the vulnerability degrees in fissured rock aquifers, while in porous aquifers the discretization is poor, in contrast with the AVI method which gives more satisfactory results. The vulnerability of the fissured rock aquifer as estimated by the DRASTIC-FM method shows significant differences compared to the original DRASTIC method. Groundwater Pollution Risk is strongly dependant on vulnerability, and consequently the use of specialized vulnerability methods provides representative and more accurate results.
-
Groundwater vulnerability and Pollution Risk assessment of porous aquifers to nitrate: Modifying the DRASTIC method using quantitative parameters
Journal of Hydrology, 2015Co-Authors: Nerantzis Kazakis, K VoudourisAbstract:In the present study the DRASTIC method was modified to estimate vulnerability and Pollution Risk of porous aquifers to nitrate. The qualitative parameters of aquifer type, soil and impact of the vadose zone were replaced with the quantitative parameters of aquifer thickness, nitrogen losses from soil and hydraulic resistance. Nitrogen losses from soil were estimated based on climatic, soil and topographic data using indices produced by the GLEAMS model. Additionally, the class range of each parameter and the final index were modified using nitrate concentration correlation with four grading methods (natural breaks, equal interval, quantile and geometrical intervals). For this reason, seventy-seven (77) groundwater samples were collected and analyzed for nitrate. Land uses were added to estimate the Pollution Risk to nitrates. The two new methods, DRASTIC-PA and DRASTIC-PAN, were then applied in the porous aquifer of Anthemountas basin together with the initial versions of DRASTIC and the LOSN-PN index. The two modified methods displayed the highest correlations with nitrate concentrations. The two new methods provided higher discretisation of the vulnerability and Pollution Risk, whereas the high variance of the (ANOVA) F statistic confirmed the increase of the average concentrations of NO3−, increasing from low to high between the vulnerability and Pollution Risk classes. The importance of the parameters of hydraulic resistance of the vadose zone, aquifer thickness and land use was confirmed by single-parameter sensitivity analysis.
Yongcun Zhao - One of the best experts on this subject based on the ideXlab platform.
-
sources of heavy metal Pollution in agricultural soils of a rapidly industrializing area in the yangtze delta of china
Ecotoxicology and Environmental Safety, 2014Co-Authors: Yongcun Zhao, Xiaoyan Zhao, Yudong Wang, Wenjing DengAbstract:The rapid industrialization and urbanization in developing countries have increased Pollution by heavy metals, which is a concern for human health and the environment. In this study, 230 surface soil samples (0-20cm) were collected from agricultural areas of Jiaxing, a rapidly industrializing area in the Yangtze Delta of China. Sequential Gaussian simulation (SGS) and multivariate factorial kriging analysis (FKA) were used to identify and explore the sources of heavy metal Pollution for eight metals (Cu, Zn, Pb, Cr, Ni, Cd, Hg and As). Localized hot-spots of Pollution were identified for Cu, Zn, Pb, Cr, Ni and Cd with area percentages of 0.48 percent, 0.58 percent, 2.84 percent, 2.41 percent, 0.74 percent, and 0.68 percent, respectively. The areas with Hg Pollution covered approximately 38 percent whereas no potential Pollution Risk was found for As. The soil parent material and point sources of Pollution had significant influences on Cr, Ni, Cu, Zn and Cd levels, except for the influence of agricultural management practices also accounted for micro-scale variations (nugget effect) for Cu and Zn Pollution. Short-range (4km) diffusion processes had a significant influence on Cu levels, although they did not appear to be the dominant sources of Zn and Cd variation. The short-range diffusion Pollution arising from current and historic industrial emissions and urbanization, and long-range (33km) variations in soil parent materials and/or diffusion jointly determined the current concentrations of soil Pb. The sources of Hg Pollution Risk may be attributed to the atmosphere deposition of industrial emission and historical use of Hg-containing pesticides.
-
estimating the Pollution Risk of cadmium in soil using a composite soil environmental quality standard
The Scientific World Journal, 2014Co-Authors: Mingkai Qu, Chuanrong Zhang, Wei Li, Biao Huang, Yongcun ZhaoAbstract:Estimating standard-exceeding probabilities of toxic metals in soil is crucial for environmental evaluation. Because soil pH and land use types have strong effects on the bioavailability of trace metals in soil, they were taken into account by some environmental protection agencies in making composite soil environmental quality standards (SEQSs) that contain multiple metal thresholds under different pH and land use conditions. This study proposed a method for estimating the standard-exceeding probability map of soil cadmium using a composite SEQS. The spatial variability and uncertainty of soil pH and site-specific land use type were incorporated through simulated realizations by sequential Gaussian simulation. A case study was conducted using a sample data set from a 150 km2 area in Wuhan City and the composite SEQS for cadmium, recently set by the State Environmental Protection Administration of China. The method may be useful for evaluating the Pollution Risks of trace metals in soil with composite SEQSs.
-
estimating the Pollution Risk of cadmium in soil using a composite soil environmental quality standard
The Scientific World Journal, 2014Co-Authors: Mingkai Qu, Chuanrong Zhang, Wei Li, Biao Huang, Yongcun ZhaoAbstract:Estimating standard-exceeding probabilities of toxic metals in soil is crucial for environmental evaluation. Because soil pH and land use types have strong effects on the bioavailability of trace metals in soil, they were taken into account by some environmental protection agencies in making composite soil environmental quality standards (SEQSs) that contain multiple metal thresholds under different pH and land use conditions. This study proposed a method for estimating the standard-exceeding probability map of soil cadmium using a composite SEQS. The spatial variability and uncertainty of soil pH and site-specific land use type were incorporated through simulated realizations by sequential Gaussian simulation. A case study was conducted using a sample data set from a 150 km2 area in Wuhan City and the composite SEQS for cadmium, recently set by the State Environmental Protection Administration of China. The method may be useful for evaluating the Pollution Risks of trace metals in soil with composite SEQSs.
Yi Liu - One of the best experts on this subject based on the ideXlab platform.
-
phosphorus spatial distribution and Pollution Risk assessment in agricultural soil around the danjiangkou reservoir china
Science of The Total Environment, 2020Co-Authors: Runhua Zhang, Chuang Liu, Runqin Zhang, Fang Chen, Yi LiuAbstract:Abstract The phosphorus (P) content in agricultural soils in catchments of lakes or rivers is an important issue because P is both an essential nutrient for high plant yields and a major contributor to eutrophication of water bodies. Thus, we have assessed the spatial distribution of soil P, impacts of environmental factors on its spatial variation, and associated Pollution Risks, in farmland around the Danjiangkou Reservoir, China. A total of 217 sites were sampled, including 121, 44 and 52 in dry cropland, paddy land and orchards, respectively. Total phosphorus (TP) contents in the sampled soils ranged from 0.230 to 1.893 g kg−1 and Olsen-P (a measure of available P) from 0.38 to 176 mg kg−1. Soil TP and Olsen-P had moderate and high variability, with coefficients of variation of 40% and 115%, respectively. Geostatistical analysis showed that both TP and Olsen-P had positive nugget effects, but TP had stronger spatial autocorrelations than Olsen-P (nugget-to-sill ratios: 22 and 50%, respectively). Total P was significantly influenced by temperature, elevation, aspect, soil pH, organic matter and precipitation, while Olsen-P was controlled by aspect and land use. The TP in soil was very similar in dry cropland and orchards (0.64 ± 0.19 and 0.61 ± 0.23 g kg−1, respectively), but substantially lower in paddy land (0.15 ± 0.25 g kg−1). Risks for P loss appeared to be very high, high, moderate and low in approximately 10, 40, 15 and 30% of the farmland in the Danjiangkou reservoir area, respectively.
-
Phosphorus spatial distribution and Pollution Risk assessment in agricultural soil around the Danjiangkou reservoir, China
ELSEVIER, 2020Co-Authors: Li Zhiguo, Zhang Runhua, Liu Chuang, Zhang Runqin, Chen Fang, Yi LiuAbstract:The phosphorus (P) content in agricultural soils in catchments of lakes or rivers is an important issue because P is both an essential nutrient for high plant yields and a major contributor to eutrophication of water bodies. Thus, we have assessed the spatial distribution of soil P, impacts of environmental factors on its spatial variation, and associated Pollution Risks, in farmland around the Danjiangkou Reservoir, China. A total of 217 sites were sampled, including 121, 44 and 52 in dry cropland, paddy land and orchards, respectively. Total phosphorus (TP) contents in the sampled soils ranged from 0.230 to 1.893 g kg(-1) and Olsen-P (a measure of available P) from 0.38 to 176 mg kg(-1) . Soil TP and Olsen-P had moderate and high variability, with coefficients of variation of 40% and 115%, respectively. Geostatistical analysis showed that both TP and Olsen-P had positive nugget effects, but TP had stronger spatial autocorrelations than Olsen-P (nugget-to-sill ratios: 22 and 50%, respectively). Total P was significantly influenced by temperature, elevation, aspect, soil pH, organic matter and precipitation, while Olsen-P was controlled by aspect and land use. The TP in soil was very similar in dry cropland and orchards (0.64 +/- 0.19 and 0.61 +/- 0.23 g kg(-1) , respectively), but substantially lower in paddy land (0.15 +/- 0.25 g kg(-1)). Risks for P loss appeared to be very high, high, moderate and low in approximately 10, 40, 15 and 30% of the farmland in the Danjiangkou reservoir area, respectively. (C) 2019 Elsevier B.V. All rights reserved
Biswajeet Pradhan - One of the best experts on this subject based on the ideXlab platform.
-
a novel machine learning based approach for the Risk assessment of nitrate groundwater contamination
Science of The Total Environment, 2018Co-Authors: Farzaneh Sajedihosseini, Biswajeet Pradhan, Arash Malekian, Bahram Choubin, Omid Rahmati, Sabrina Cipullo, Frederic CoulonAbstract:This study aimed to develop a novel framework for Risk assessment of nitrate groundwater contamination by integrating chemical and statistical analysis for an arid region. A standard method was applied for assessing the vulnerability of groundwater to nitrate Pollution in Lenjanat plain, Iran. Nitrate concentration were collected from 102 wells of the plain and used to provide Pollution occurrence and probability maps. Three machine learning models including boosted regression trees (BRT), multivariate discriminant analysis (MDA), and support vector machine (SVM) were used for the probability of groundwater Pollution occurrence. Afterwards, an ensemble modeling approach was applied for production of the groundwater Pollution occurrence probability map. Validation of the models was carried out using area under the receiver operating characteristic curve method (AUC); values above 80% were selected to contribute in ensembling process. Results indicated that accuracy for the three models ranged from 0.81 to 0.87, therefore all models were considered for ensemble modeling process. The resultant groundwater Pollution Risk (produced by vulnerability, Pollution, and probability maps) indicated that the central regions of the plain have high and very high Risk of nitrate Pollution further confirmed by the exiting landuse map. The findings may provide very helpful information in decision making for groundwater Pollution Risk management especially in semi-arid regions.
-
Risk assessment of groundwater Pollution with a new methodological framework application of dempster shafer theory and gis
Natural Hazards, 2015Co-Authors: Aminreza Neshat, Biswajeet PradhanAbstract:Managing natural groundwater resources is challenged by nitrate Pollution resulting from agricultural activities. This issue is emerging as an important environmental concern that needs to be addressed through effective groundwater management. Groundwater assessment is an important aspect of groundwater management, particularly in arid and semi-arid regions. This study focused on the Kerman Plain, which is exposed to intensive agricultural activities and land exploitation that result in intense land Pollution. The effects of nitrate Pollution may be controlled by applying specific measures. Dempster–Shafer theory (DST) was applied in this study to develop a new methodology for assessing Pollution Risk. Applying this theory as a pioneering approach to assessing groundwater Pollution Risk is the novel component of this research. This approach provides a major advantage by dealing with varying levels of precision related to information. The spatial association between DRASTIC parameters including D (depth of water), R (net recharge), A (aquifer media), S (soil media), T (topography), I (impact of vadose zone) and C (hydraulic conductivity) and underground nitrate occurrence was evaluated by applying bivariate DST to assign mass functions. Dempster’s rule of combination using GIS was then applied to determine a series of combined mass functions for multiple hydrogeological data layers. The uncertainty of system responses was directly addressed by the proposed methodology. Finally, the modified DRASTIC map with the highest validity and accuracy was selected and combined with the damage map. The comparison between nitrate distribution and vulnerability and the Risk maps exhibit high similarity between different vulnerability degrees and nitrate concentrations. Long-term planning of preventive measures and associated developments can be aided by the regions with low and very low Risks located in the northeast, northwest, and central regions.