Geology topics
Lori E. Apodaca
Publications and source records attributed to Lori E. Apodaca.
Nitrogen
The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.
Peat
The article looks at the U.S. peat market as of July 2013. Peat is produced from deposits of plant organic materials in wetlands and includes varieties such as reed-sedge, sphagnum moss, and humus. Use for peat include horticultural soil additives, filtration, and adsorbents. Other topics include effects of environmental protection regulations on peat extraction, competition from products such as coir, composted organic waste, and wood products, and peatland carbon sinks.
Trace elements and radon in groundwater across the United States, 1992-2003
Trace-element concentrations in groundwater were evaluated for samples collected between 1992 and 2003 from aquifers across the United States as part of the U.S. Geological Survey National Water-Quality Assessment Program. This study describes the first comprehensive analysis of those data by assessing occurrence (concentrations above analytical reporting levels) and by comparing concentrations to human-health benchmarks (HHBs). Data from 5,183 monitoring and drinking-water wells representing more than 40 principal and other aquifers in humid and dry regions and in various land-use settings were used in the analysis. Trace elements measured include aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn). Radon (Rn) gas also was measured and is included in the data analysis. Climate influenced the occurrence and distribution of trace elements in groundwater whereby more trace elements occurred and were found at greater concentrations in wells in drier regions of the United States than in humid regions. In particular, the concentrations of As, Ba, B, Cr, Cu, Mo, Ni, Se, Sr, U, V, and Zn were greater in the drier regions, where processes such as chemical evolution, ion complexation, evaporative concentration, and redox (oxidation-reduction) controls act to varying degrees to mobilize these elements. Al, Co, Fe, Pb, and Mn concentrations in groundwater were greater in humid regions of the United States than in dry regions, partly in response to lower groundwater pH and (or) more frequent anoxic conditions. In groundwater from humid regions, concentrations of Cu, Pb, Rn, and Zn were significantly greater in drinking-water wells than in monitoring wells. Samples from drinking-water wells in dry regions had greater concentrations of As, Ba, Pb, Li, Sr, V, and Zn, than samples from monitoring wells. In humid regions, however, concentrations of most trace elements were greater in monitoring wells than in drinking-water wells; the exceptions were Cu, Pb, Zn, and Rn. Cu, Pb, and Zn are common trace elements in pumps and pipes used in the construction of drinking-water wells, and contamination from these sources may have contributed to their concentrations. Al, Sb, Ba, B, Cr, Co, Fe, Mn, Mo, Ni, Se, Sr, and U concentrations were all greater in monitoring wells than in drinking-water wells in humid regions. Groundwater from wells in agricultural settings had greater concentrations of As, Mo, and U than groundwater from wells in urban settings, possibly owing to greater pH in the agricultural wells. Significantly greater concentrations of B, Cr, Se, Ag, Sr, and V also were found in agricultural wells in dry regions. Groundwater from dry-region urban wells had greater concentrations of Co, Fe, Pb, Li, Mn, and specific conductance than groundwater from agricultural wells. The geologic composition of aquifers and aquifer geochemistry are among the major factors affecting trace-element occurrence. Trace-element concentrations in groundwater were characterized in aquifers from eight major groups based on geologic material, including (1) unconsolidated sand and gravel; (2) glacial unconsolidated sand and gravel; (3) semiconsolidated sand; (4) sandstone; (5) sandstone and carbonate rock; (6) carbonate rock; (7) basaltic and other volcanic rock; and (8) crystalline rock. The majority of groundwater samples and the largest percentages of exceedences of HHBs were in the glacial and nonglacial unconsolidated sand and gravel aquifers; in these aquifers, As, Mn, and U are the most common trace elements exceeding HHBs. Overall, 19 percent of wells (962 of 5,097) exceeded an HHB for at least one trace element. The trace elements with HHBs included in this summary were Sb, As, Ba, Be, B, Cd, Cr,
Bromine
The entire U.S. production of bromine in 2009 came from underground brines in Arkansas, where it was the leading mineral commodity produced in terms of value. Two companies, Albermarle Corp. and Chemtura Corp., were responsible for bromine recovery. Worldwide, the United States is still the leading producer. However, U.S. dominance has decreased, as countries like China, Israel, Japan and Jordan have strengthened their positions as world producers of elemental bromine.
Review of Trace Element Blank and Replicate Data Collected in Ground and Surface Water for the National Water-Quality Assessment Program, 1991-2002
The trace elements Sb, Be, and Tl in ground water and Sb, Be, Co, Mo, and U in surface water are unaffected by contamination. Limited quality control data (blanks) for Li and V in ground water and surface water do not allow for a good assessment on the potential contamination associated with these trace elements. Potential contamination was identified for Al, As, Ba, B, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Se, Ag, Sr, and Zn in ground water and surface water. Evidence of potential contamination was shown for Co, Mo, and U in ground water; potential contamination was shown for T1 in surface water. In comparing the potential contamination for these trace elements with the U.S. Environmental Protection Agency's (USEPA) drinking-water standards, the contamination for most of these trace elements is less than 10 percent of the drinking-water standard; therefore, contamination would have little or no effect when comparing trace element concentrations with the USEPA drinking-water standards. The exceptions are Al, Cd, and possibly Pb in ground water, and As and possibly Pb in surface water. Potential contamination identified for these trace elements is greater than 10 percent of the USEPA drinking-water standard, but affects only 5 percent or less of the As, Cd, and Pb samples. For most trace elements, the level of potential contamination is not large enough to significantly affect the measured concentration of the environmental sample. The exceptions may be Fe in ground water and Al in surface water, which have concentrations for at least 10 percent of the environmental samples that exceeded the USEPA drinking-water standards. Sample variability for some of the trace elements could not be determined because there were either no detected concentrations, or there were less than 10 replicate sets with detected concentrations. These trace elements are Be, Ag, and Tl for ground water and Sb, Be, Cr, Co, Pb, Ag, and Tl for surface water. For most trace elements, sample variability was less than 10 percent, which would have little or no affect on the reported concentrations. The exceptions are Al, Cd, Cu, Pb, Rn (at concentrations less than about 700 picocuries per liter), Se, and Zn in ground water and Cu, Se, and Zn in surface water, all of which have sample variability ranging from 10 to 20 percent. Sample variability should be considered when evaluating the potential error associated with a sample measurement. Collection of additional quality control samples for some of these trace elements to determine bias and variability is probably warranted particularly for those trace elements that the NAWQA Program did not begin sampling until 1998. Results obtained from the analysis of the quality control data can be applied to the interpretation of the environmental data collected from 1991 to 2002 and for water-quality data that are currently being collected as part of the NAWQA Program. More...
Water quality in the upper Colorado River basin, Colorado, 1996-98
This report summarizes major findings about water quality in the upper Colorado River basin that emerged from an assessment conducted between 1996 and 1998 by the U.S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) Program. Water quality is discussed in terms of local and regional issues and compared to conditions found in all 36 NAWQA study areas assessed to date. Findings are also explained in the context of selected national benchmarks, such as those for drinking water quality and the protection of aquatic organisms.
Environmental Setting and Implications on Water Quality, Upper Colorado River Basin, Colorado and Utah
The Upper Colorado River Basin in Colorado and Utah is 1 of 60 study units selected for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment program, which began full implementation in 1991. Understanding the environmental setting of the Upper Colorado River Basin study unit is important in evaluating water-quality issues in the basin. Natural and human factors that affect water quality in the basin are presented, including an overview of the physiography, climatic conditions, general geology and soils, ecoregions, population, land use, water management and use, hydrologic characteristics, and to the extent possible aquatic biology. These factors have substantial implications on water-quality conditions in the basin. For example, high concentrations of dissolved solids and selenium are present in the natural background water conditions of surface and ground water in parts ofthe basin. In addition, mining, urban, and agricultural land and water uses result in the presence of certain constituents in the surface and ground water of the basin that can detrimentally affect water quality. The environmental setting of the study unit provides a framework of the basin characteristics, which is important in the design of integrated studies of surface water, ground water, and biology.