Field scale interaction and nutrient exchange between surface water and shallow groundwater in the Baiyang Lake region, North China Plain

Fertilizer input for agricultural food production, as well as the discharge of domestic and industrial water pollutants, increases pressures on locally scarce and vulnerable water resources in the North China Plain. In order to: (a) understand pollutant exchange between surface water and groundwater, (b) quantify nutrient loadings, and (c) identify major nutrient removal pathways by using qualitative and quantitative methods, including the geochemical model PHREEQC) a one-year study at a wheat (Triticum ciestiu um L.) and maize (Zea mays L.) double cropping system in the Baiyang Lake area in Hebei Province, China, was undertaken. The study showed a high influence of low-quality surface water on the shallow aquifer. Major inflowing pollutants into the aquifer were ammonium and nitrate via inflow from the adjacent Fu River (up to 29.8 mg/L NH4-N and 6.8 mg/L NO3-N), as well as nitrate via vertical transport from the field surface (up to 134.8 mg/L NO3-N in soil water). Results from a conceptual model show an excess nitrogen input of about 320 kg/ha/a. Nevertheless, both nitrogen species were only detected at low concentrations in shallow groundwater, averaging at 3.6 mg/L NH4-N and 1.8 mg/L NO3-N. Measurement results supported by PHREEQC-modeling indicated cation exchange, denitrification, and anaerobic ammonium oxidation coupled with partial denitrification as major nitrogen removal pathways. Despite the current removal capacity, the excessive nitrogen fertilization may pose a future threat to groundwater quality. Surface water quality improvements are therefore recommended in conjunction with simultaneous monitoring of nitrate in the aquifer, and reduced agricultural N-inputs should be considered. (C) 2016 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

Evaluation of Hydrogeochemical Characteristics of San Joaquin, Tulare, and Mojave Aquifers, Southern California

Before making attempts to enhance and manage the quality of water, a thorough understanding of these processes is necessary since the chemical quality of groundwater is impacted by a number of linked processes. This would be more important in arid and semiarid regions like the southern part of California where more rely on groundwater for agriculture and drinking water uses than the other states. As a result, fundamental knowledge of the governing processes of groundwater chemistry is required for effective water resource management. Thus, this study is primarily concerned with three aspects in Mojave, Tulare, and San Joaquin aquifers: The first step is chemical properties of groundwater with respect to hydrogeochemical aspects and salinity. Without different managerial approaches, irrigation with poor-quality water can have a variety of adverse effects, such as increased soil salinity/sodicity, poor penetration, soil hardening, and/or plant-specific ion toxicity. Together, these variables inhibit crop growth and, eventually, a crop\u27s economic output. Numerous indices have been proposed and are often employed in groundwater for this purpose, including Na%, SAR (sodium adsorption ratio), RSC (residual sodium carbonate), MH (magnesium hazard), PI (permeability index), and PS (potential salinity). In the second section, we go into more detail about the levels of heavy metals in groundwater and how pollution indices like HPI (heavy metal pollution index), HEI (heavy metal evaluation index), and CI (contamination index) can be used to evaluate the health risks of consuming groundwater that is overly contaminated with these heavy metals. The concentration of nitrate in the aquifers is the third factor. The multi-isotope systematics (δ15N- and δ18O-NO3) method is highlighted in this study, along with typical δ15N- and δ18O-NO3 ranges of known NO3 sources, as well as many other parameters, including the effects of pH, EC, reduction-oxidation, and other elements/ions on nitrate concentration and δ15N- and δ18O-NO3 determination. In addition, this paper covers how to map water quality indicators in the Mojave, Tulare, and San Joaquin aquifers using a GIS (geographical information system) based on water quality information system and spatial analysis with IDW (inverse distance weighted) interpolation

Evaluation of Hydrogeochemical Characteristics of San Joaquin, Tulare, and Mojave Aquifers, Southern California

Before making attempts to enhance and manage the quality of water, a thorough understanding of these processes is necessary since the chemical quality of groundwater is impacted by a number of linked processes. This would be more important in arid and semiarid regions like the southern part of California where more rely on groundwater for agriculture and drinking water uses than the other states. As a result, fundamental knowledge of the governing processes of groundwater chemistry is required for effective water resource management. Thus, this study is primarily concerned with three aspects in Mojave, Tulare, and San Joaquin aquifers: The first step is chemical properties of groundwater with respect to hydrogeochemical aspects and salinity. Without different managerial approaches, irrigation with poor-quality water can have a variety of adverse effects, such as increased soil salinity/sodicity, poor penetration, soil hardening, and/or plant-specific ion toxicity. Together, these variables inhibit crop growth and, eventually, a crop\u27s economic output. Numerous indices have been proposed and are often employed in groundwater for this purpose, including Na%, SAR (sodium adsorption ratio), RSC (residual sodium carbonate), MH (magnesium hazard), PI (permeability index), and PS (potential salinity). In the second section, we go into more detail about the levels of heavy metals in groundwater and how pollution indices like HPI (heavy metal pollution index), HEI (heavy metal evaluation index), and CI (contamination index) can be used to evaluate the health risks of consuming groundwater that is overly contaminated with these heavy metals. The concentration of nitrate in the aquifers is the third factor. The multi-isotope systematics (δ15N- and δ18O-NO3) method is highlighted in this study, along with typical δ15N- and δ18O-NO3 ranges of known NO3 sources, as well as many other parameters, including the effects of pH, EC, reduction-oxidation, and other elements/ions on nitrate concentration and δ15N- and δ18O-NO3 determination. In addition, this paper covers how to map water quality indicators in the Mojave, Tulare, and San Joaquin aquifers using a GIS (geographical information system) based on water quality information system and spatial analysis with IDW (inverse distance weighted) interpolation