The biodegradation of 4-octylphenoxyacetic acid (OP1EC) was studied in laboratory columns to determine the residual concentration that can persist during groundwater recharge or transport. Biofilm models predict residual concentrations are independent of the initial concentration and residence time. Two column trains, constructed with glass beads and providing a residence time of 280 min were f...

Sulfur hexafluoride (SF6) has the potential to be a valuable transient racer for dating of young ground water. However, near urban areas, there are typically numerous point sources of SF6 which have a significant impact on the temporal evolution of its atmospheric mixing ratio, thereby complicating its use as an age-dating tool. Here, we present and discuss a 12-month record of atmospheric SF6 ...

This study conducts a detailed analysis of multiscale periodic features involved in the annual and seasonal precipitation signals at the typical coastal reclamation region in China by selecting the suitable continuous wavelet transform (CWT) and innovatively combining the improved Hilbert–Huang transform (HHT), and further deduces the precipitation trend and its impacts on the future soil hydro...

Rapid population growth and increasing demand for the modern settlement has led to the increase of environmental pollution. Limestone quarry is one among the activities that affect environment and ecosystem in Pemba Island-Zanzibar. Quarrying activities brought an inevitable destruction to the environments ranging from excavation, soil and land degradation, loose of biodiversity and water pollu...

We used two short-lived radium isotopes (223Ra, 224Ra) and a mass balance approach applied to the radium activities to determine the nutrient contribution of saline submarine groundwater discharge to the coastal waters of the northern Gulf of Aqaba (Israel). Radium isotope activities were measured along transects during two seasons at a site that lacked any obvious surficial water input. An ons...

Lack of sewage collection systems, percolation of surface waters, and seepage of wells have raised the groundwater table in Shiraz area in the south of Iran. The growing population generates environmental pollution resulting in the degradation of the quality of surface and groundwaters used for agriculture. Inorganic and organic pollutants have been traced in Shiraz water resources. Heavy metal...

Saharan paleo-groundwater from the Hasouna area of Libya contains up to 1.8 mM of nitrate, which exceeds the World Health Organization limit for drinking water, but the origin is still disputed. Herein we show that a positive 17O excess in NO−3 (1 ONO3 = δ ONO3−0.52δ ONO3) is preserved in the paleo-groundwater. The 17O excess provides an excellent tracer of atmospheric NO−3 , which is caused by...

The hydrologic connectivity between hillslopes and streams impacts the geomorphological evolution of catchments. Here, we propose a conceptual model for hydrogeomorphological evolution of the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO), a first-order catchment developed on shale in central Pennsylvania, U.S.A. At SSHCZO, the majority of available water (the difference between inc...

Areas of the Last Glaciation in northern Poland differ widely as to the conditions controlling the formation of river runoff and solute loads. The aim of the research was to identify chief mechanisms of stream alimentation in this area depending on the scale of a catchment. The analysis rested on data from hydrochemical profiling. Three types of systems were found to occur: in spring-head catch...

[1] The mixing zone between freshwater and seawater in a coastal aquifer is an important transition region that controls regional groundwater flow dynamics and reactive transport processes. While experimental procedures have been developed to study the movement of salt wedges in aquifers, so far no one has attempted to exclusivelymap themixing zone associated with the wedge in a laboratory-scal...