Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1981. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 225-239. / by Robert William Collier. / Ph.D.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 235-250. / Ph.D.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Vita. / Includes bibliographical references. / Ph.D.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Includes bibliographical references. / M.S.

Four untreated and one magnesium treated water samples from Lake Washington, the potable water source for the city of Melbourne, Florida, were collected and analyzed for As, Cd, Cr, Cu, Fe, Pb, Ni, Zn, Mb, Ca, and color on the basis of molecular weight distribution. Molecular weight distributions of the samples were obtained using a Millipore ultrafiltration system and filters in the following sizes: 106, 105, 2.5 x 104, 104, and 103 nominal molecular weight limits (nmwl). Color causing materials in the untreated samples were found to be located in the molecular weight fraction greater than 2.5 x 104 nmwl. The majority of the metals concentrations (approximately greater than 80%) were also found to be located in the molecular weight fraction greater than 2.5 x 104 nmwl. Analysis of the magnesium treated (for maximum color removal) sample showed higher concentrations of metals passing the respective filter sizes as opposed to the untreated samples indicating less complexation or smaller molecular complexes of the metals. Thus, a fairly strong correlation between heavy metals concentrations and color in the Lake Washington samples was indicated.

Concentrations of Fe, Al, Mn and Zn were measured monthly from April to October at 24 rural riverine sites in Ontario and Quebec. Empirical models were developed predicting riverine metal concentrations from a small set of within-stream and catchment variables. Models explained a significant proportion of the variation in Fe (85%), Al (90%), Mn (57%) and Zn (37%). Simple models predicting annual catchment exports of metals from average riverine suspended particulate concentrations and runoff were also developed. These models explained most of the variation in annual exports of Fe (94%), Al (92%), Mn (62%) and Zn (75%) from the 24 catchments. / Models such as these can be used both to estimate catchment exports of metals to lakes, and to estimate riverine metal concentrations without requiring chemical analyses. The models also serve to distinguish background levels from those indicating metal contamination, and will, therefore, be useful in design of water quality guidelines.

No description available.

This study was carried out in the Souris and Turtle Rivers in North Dakota. The aim of this study was to develop multi-element fingerprints of the Souris River and Turtle River sediments and to evaluate the suitability of these fingerprints to assess the geographic origin of potential pollutants of the two rivers. Preliminary analysis of Souris River sediment samples confirmed that the multi-element fingerprinting can be used to assess the sediment and contaminant loading patterns. Laboratory experiments were performed to assess the validity of linear mixing assumption in multi-element fingerprinting studies. The results of these experiments verified the assumptions and showed that there is a statistically significant spatial and temporal variation in the element concentrations depending on their mobility and re-deposition. Field studies were conducted in the Souris River and Turtle River to assess the variation of element concentrations in the top riverbed samples along the main rivers and their tributaries. The sediment contribution from the tributaries and the phosphorus concentrations in the main channel were used to calculate the phosphorus contributions from the tributary sediments to the Souris River. The differences in phosphorus contributions from tributaries were related to land use, underlying geology, and the size of the watersheds of the tributaries in the Souris River watershed. Similar analysis was used in the Turtle River to calculate Arsenic, Cadmium and Selenium contribution from the tributaries to the Turtle River. The differences in the contribution of these elements were related to the underlying geology and the size of the watersheds. This study provides a detailed analysis of element concentrations and relative sediments and element loading rates from the tributaries to the main rivers along the Souris and Turtle Rivers in North Dakota. The multi-element fingerprinting technique can be successfully used as a tool to identify the relative contribution of sediments and assessing and tracing pollution sources in rivers. Multi-element fingerprinting provides a relatively low cost, rapid tool for sediment tracking, without the need for addition of exotic chemicals such radio-tracers or dyes to natural ecosystems. / North Dakota State University. College of Science and Mathematics / North Dakota State University. Department of Biological Sciences. Environmental Conservation Sciences Program / North Dakota Department of Health / ND INBRE / North Dakota Water Resources Research Institute / North Dakota State Water Commission

The geochemistry, of groundwater collected from deep wells in the western section of the lower Santa Cruz basin of southeastern Arizona, was studied in order to determine the extent to which geochemica] analysis can be used to assess fluid flow and major and trace element migration patterns along hydrologic flowpaths in desert basins. Interaction between groundwater and enclosing sediments, and mixing between chemically distinct basin groundwater is found to exert a significant control on the chemical patterns that have evolved in the system. Activity-activity diagrams of the Na-Si-O-H system show that groundwater throughout the basin clusters near the three phase boundary between fluid, kaolinite, and montmorillonite and trends along the boundary to higher log (aNa⁺/aH⁺) values. A reaction model generated with computer program PHREEQE, that combines silicate weathering, kaolinite-Na-beidellite equilibrium, calcite equilibrium, and solution mixing, can simulate trends in groundwater composition along flowpaths in the basin. Trace metals introduced into the basin by the weathering of a buried porphyry copper deposit become spatially separated upon migration. Metal concentrations are found to be correlated to major cation concentrations. Cu is associated with high Na concentrations and a high ratio of Carbonate:Ca, whereas Zn is associated with high Ca concentration and a low ratio of Carbonate:Ca. Behavior of Cu and Zn during low-temperature transport can be controlled by the effects of mineral alteration on groundwater composition. Computer analysis of early basin diagenesis shows that changes in major solute composition that accompany weathering, constrained by equilibrium with clays and calcite, can produce the metal segregation pattern observed in the basin. Because the aquifer is strongly influenced by silicate and carbonate mineral equilibrium, the introduction of Central Arizona Project recharge, which is not in equilibrium with alluvial minerals, into the basin, requires a response by mineral reactions that attempt to restore the system to a state of equilibrium with kaolinite, montmorillonite, and calcite. A reaction model is developed to predict the consequent effects of outside recharge on groundwater quality.

The occurrence of As in groundwater in Argentina was known since 1917; however, the occurrence, distribution and mobilization of As and other trace elements (TEs) in groundwater in the Bolivian Altiplano are still quite unknown. An investigation applying a geochemical approach was conducted in the Poopó Basin and Lake Titicaca to understand processes of TEs in different systems such as water, soils, crops and sediments in mining areas. In Poopó Basin,As, Cd and Mn concentrations exceed World Health Organization (WHO) guidelines and Bolivian regulations for drinking water in different places around the basin, but Cu, Ni, Pb and Zn do not. In soils, the sequential extraction methods extracted up to 12% (fractions 1 and 2), which represent &lt; 3.1 mg/kg of the total As content, as potentially mobilized fractions, that could be transferred to crops and/or dissolved in hydrologic system. The large pool of As can be attached due to amorphous and crystalline Fe oxide surfaces (fractions 3, 4, and 5) present in the soils. Furthermore, the concentrations of As, Cd and Pb in the edible part of the crops revealed that the concentrations of As and Cd do not exceed the international regulation (FAO, WHO, EC, Chilean) (0.50 mg/kgfw for As and 0.10 mg/kgfw for Cd), while Pb exceeds the international regulations for beans and potatoes (for beans 0.20 mg/kgfw and for potato 0.10 mg/kgfw). In the Lake Titicaca, principal component analysis (PCA) of TEs in sediments suggests that the Co-Ni-Cd association can be attributed to natural sources such as rock mineralization, while Cu-Fe-Mn come from effluents and mining activities, whereas Pb-Zn are mainly related to mining activities. The Risk Assessment Code (RAC) indicate “moderately to high risk” for mobilization of Cd, Co, Mn, Ni, Pb and Zn, while Cu and Fe indicate “low to moderate risk” for remobilization in the water column. / <p>QC 20140604</p> / Hydrochemistry: Arsenic and heavy metals in the Lake Poopó Basin (Sida contribution: 7500707606) / Catchment Management and Mining Impacts in Arid and semi-arid South America (CAMINAR) (INCO-CT-2006-032539)