Decomposition approach of the nitrogen generation process: empirical study on the Shimabara Peninsula in Japan.

Groundwater nitrate pollution is one of the most prevalent water-related environmental problems worldwide. The objective of this study is to identify the determinants of nitrogen pollutant changes with a focus on the nitrogen generation process. The novelty of our research framework is to cost-effectively identify the factors involved in nitrogen pollutant generation using public data.

Barometric and tidal-induced aquifer water level fluctuation near the Ariake Sea.

Observations of water levels in coastal aquifers and corresponding tides coupled with meteorological variances near the Ariake Sea show that groundwater in this area mainly fluctuates with atmospheric and tidal variations. Tidal effects occur with semi-monthly, diurnal, or semi-diurnal periodicity, whereas the barometric influences commonly act in the low-frequency domain. Tidal and barometric effects in water levels are separable using wavelet techniques and can be evaluated statistically.

The use of δ15N and δ18O tracers with an understanding of groundwater flow dynamics for evaluating the origins and attenuation mechanisms of nitrate pollution.

During early 2000, a new analytical procedure for nitrate isotopic measurement, termed the "denitrifier method", was established. With the development of the nitrate isotope tracer method, much research has been reported detailing sources of groundwater nitrate and denitrification mechanisms. However, a shortcoming of these tracer studies has been indicated owing to some overlapping of isotope compositions among different source materials and denitrification trends.

Spring water quality and usability in the Mount Cameroon area revealed by hydrogeochemistry.

Groundwater is the only reliable water resource for drinking, domestic, and agricultural purposes for the people living in the Mount Cameroon area. Hydrogeochemical and R-mode factor analysis were used to identify hydrogeochemical processes controlling spring water quality and assess its usability for the above uses. Main water types in the study area are Ca-Mg-HCO(3) and Na-HCO(3).

Evolution model of δ³⁴S and δ¹⁸O in dissolved sulfate in volcanic fan aquifers from recharge to coastal zone and through the Jakarta urban area, Indonesia.

The sources of sulfate in an aquifer system, and its formation/degradation via biogeochemical reactions, were investigated by determining sulfate isotope ratios (δ³⁴S(SO₄) and δ¹⁸O(SO₄) in dissolved sulfate in groundwater from the Jakarta Basin. The groundwater flow paths, water ages, and geochemical features are well known from previous studies, providing a framework for the groundwater chemical and isotopic data, which is supplemented with data for spring water, river water, hot spring water, seawater, detergents, and fertilizers within the basin. The sulfate isotope composition of groundwater samples varied widely from -2.