An Analysis of Nitrate-Nitrogen in Ground Water Beneath Unsewered Subdivisions

Water samples from private water supply wells in five unsewered subdivisions were tested for nitrate-nitrogen to determine the possible impact of septic systems on ground water quality. Three subdivisions are located in Eau Claire County and two in LaCrosse County, Wisconsin.
The nitrate-nitrogen concentrations in the wells were analyzed in relation to ground water flow direction, the location of septic systems within the subdivision, and the hydrogeologic and physical characteristics of the subdivisions. A comparison of three nitrogen mass balance models helped to identify the possible sources of nitrate-nitrogen in the wells.
The results indicate that nitrogen from septic systems and lawn fertilizer cause nitrate-nitrogen to increase in the ground water beneath the downgradient side of the subdivisions. In three of the five subdivisions the highest nitrate-nitrogen value exceeds the drinking water standard of 10 mg/L.     

Radium in Coastal Sarasota County Ground Water

Sarasota County is one of 10 generalized areas of the continental United States known to haw high concentrations of naturally occurring radium in fresh ground water (Chandler 1989). Various authors have conducted investigations to examine the distribution of radium in ground water, rivers, and estuaries. They concluded that ground water was the source of radium, but rivers were also enriched with radium as a result of the interaction with ground water. The Glulf of Mexico also has areas with radium enrichment resulting from geothermal springs with concentrations as high as 51 picocuries per liter. During 1986 and 1987. the Health and Rehabilitative Services of the state of Florida collected ground water data for radium analysis of private drinking water wells. These data were used to develop a contour map of radium-226 concentrations for coastal Sarasota County.     

Ground Water Loading of Pesticides in the Atlantic Coastal Plain

Pollution of ground water by agricultural practices has gained considerable attention in recent years. Mathematical models have been developed to evaluate the effects of agricultural best management practices on pesticide transport to ground water. The GLEAMS model was evaluated to determine its suitability for use in predicting managerial effects on pesticide leaching from agricultural systems in the Atlantic Coastal Plain. Model predictions of pesticide concentrations in percolation from the root zone were compared to observed concentrations in ground water beneath field-sized areas. The model underpredicted runoff from these areas. Model predictions were used to produce rankings of the magnitudes of pesticide losses that paralleled rankings of observed ground water data in some cases but not others. Differences in observed and predicted rankings were assessed to be the result of sampling schedule inefficiences. The magnitudes of predicted pesticide concentrations in leachate from the root zone were three to seven times higher than observed concentrations in shallow ground water. Results support the use of GLEAMS for comparison of managerial effects on pesticide movement to ground water if appropriate limitations are recognized.     

An Evaluation Technique for Ground Water Quality Beneath Urban Runoff Retention and Percolation Basins

A subsurface water (vadose zone or ground water) extractor is described. Construction materials were Teflon and a porous ceramic suction cup. The unique features are:
  •Check valves are not needed.
  •Complete retention of water sample in a 1.8L capacity reservoir, even if vacuum is lost or when the reservoir is pressurized to transfer sample to ground surface and the collection bottle.
  •The extractor can usually be retrieved if the access well and well head as described are used. The ceramic cup can then be replaced if necessary and the extractor reused at another site. The water extractor is not suitable for obtaining samples for analysis of highly volatile pollutants.
Up to four of these water extractors were used to monitor the quality of percolating urban runoff water and top of the ground water table (20 to 30m) beneath retention/recharge basins. The presence of water in the basins requires constructing a sealed borehole annular space, a watertight well head, and seal around the Teflon access tubes to the extractor at a control box containing the valves in the access tubes.     

Coastal and oceanic SST variability along the western Iberian Peninsula

The inter-annual variability of the sea surface temperature (SST) was analyzed along the western Iberian Peninsula in the region ranging from 9.5 °W to 21.5 °W and from 37.5 °N to 42.5 °N with a spatial resolution of 1°×1° from 1900 to 2008. Both coastal and oceanic SST showed an overall increase with warming and cooling cycles similar to those observed in the North Atlantic region and in previous regional studies. In addition, the evolution of coastal and ocean water has been observed to be different. In general, ocean water is more affected by the different warming–cooling cycles than coastal water. In spite of coast and ocean are highly influenced by global changes affecting the whole North Atlantic region, near shore SST has been observed to be correlated with local wind regime, which is itself a manifestation of the Eastern Atlantic (EA) teleconnection pattern.     

Assessing External Water Exchange of Lake Bays by Water Chemistry Characteristics

Water Resources - External water exchange of bays of the lakes Onega (Kondopoga and Petrozavodsk bays) and Ladoga (Hiidenselkä Bay), considering the exchange with the lake water, was assessed...