Seawater sources

Figure5.2. Suppression of indophe-nol blue response to ammonia by nitrite ion in seawater 0.4 ppm ammonia N in seawater. Source [56]... 

Supporting a seawater source for the halogens is the observation by Shepson and co-workers of significant amounts of as yet unidentified photolyzable chlorine as well as bromine compounds in the spring in the Arctic (Impey et al., 1997a, 1997b). In addition, Platt and co-workers have detected both BrO and CIO at the surface during ozone depletion events (Platt and Haus-mann, 1994 Hausmann and Platt, 1994 Tuckermann et al, 1997). 

FIGURE 1-1 Relationship between the depth of the disabled submarine, the internal pressure of the submarine, and the percentage of the crew members likely to suffer from decompression sickness. Abbreviations DCS, decompression sickness DISSUB, disabled submarine fsw, feet seawater. Source Parker et al. 2000. Reprinted with permission from Aviation Space and Environmental Medicine, copyright 2000, Aerospace Medical Association, Alexandria, Virginia. 

Na-Cl variations in evaporated seawater (source represent Ca-Cl variations in evaporated seawater Hanor, 2001). (source Hanor, 2001). 

Figure 11 The solubility of Fe(III) in NaCl, NaCl plus the major cations and anions, and artificial seawater (source...

Figure 15 Plot of fe/a(Cu+) for the oxidation of Cu(I) with O2 in seawater (source Sharma and MiUero, 1988a).

Figure 9 Variations of Na/Cl, Br/Cl, and values during evaporation of seawater. Degree of evaporation is defined as the ratio of Br in the solution at different stages of evaporation to the initial Br in seawater (sources McCaffrey et al., 1987 Raab and Spiro, 1991 Vengosh et al., 1992).

A schematic representation of the sources and sinks of the dissolved chemical constituents of seawater. Sources are from rivers and wind, and sinks are authigenic mineral formation. 

Table V presents fits to a variety of seawater types adjusted to various pH values. Here the B values are uniformly higher than in Table IV and quite unstable for technical reasons (Appendix, Fig. 3). It is not possible to select objectively the "better" data, and the relatively small discrepancies in the a terms do not drastically affect our interpretation. The most important trends of Tables IV and V are that the seawater pseudo first-order rate constant, a, appears to be independent of seawater source (hence, of trace constituents), to be simulated well by artificial seawater, and to be pH...

Hence a reaction of this type taken to completion will produce sulphide diepleted by 22 "/i relative to the seawater source. 

Evidence from lanthanide abundances identified the source of metalliferous sediments deposited at mid-ocean ridges. They possessed a significant depletion in Ce, pointing clearly to a seawater source for the lanthanides present in the hydrothermal solutions (Piper and Graf 1974, Fleet 1984). 

In a seawater source operating on-site hypochlorite cell there typically is an abundance of seawater normally with a salt concentration above 15 gpl NaCl. The only significant cost in operating these on-site seawater systems is electricity to drive the electrolytic cells and pumping cost feed stock seawater is considered free. Therefore seawater cells are operated to maximize production (minimize inefficiency reactions) and reduce operating cell voltage to minimize electricity consumption. 

The mineral/salt content of the water is usually measured by the water quality parameter total dissolved solids (TDS), in milligrams per liter (mg/L) or parts per thousand (ppt). Natural water sources such as sea, bay, and ocean waters usually have TDS concentration higher than 15,000 mg/L. Seawater TDS and temperature are the two key source water quality parameters that have the most significant influence on the cost of seawater desalination. Table 3.2 presents typical TDS concentration and temperature for various seawater sources. 

TABLE 3.2 Salinity and Temperature of Various Seawater Sources"... 

Seawater Source Total Dissolved Solids Concentration (mg/L) Temperature (°C)... 

Many reactions between fluorophores and their environment will reduce DOM fluorescence and are termed quenching reactions. Huorescence is related primarily to various chemical components constituting DOM, which is reflects DOM sources and molecular size and mass. Colloidal organic matter (COM), fractionated by a variety of ultrafiltration and flow fractionation methods, shows distinct patterns in fluorescence, but these patterns are not consistent among freshwater and seawater sources. In freshwater environments protein fluorescence is often found in the highest molecular size fractions, whereas in seawater environments, fluorescence is often found in lower molecular size fractions. 

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