Factor river

Seawater chemistry is determined by several factors. River water input, hydrothermal solution input, evaporation of seawater, interactiOTi of seawater with oceanic crust and anthropogenic influence are important factors. It is simply assumed that seawater chemistry is controlled by input and output fluxes and chemical reaction in the system. Reversible chemical reaction will be considered below. 

Cost Fa.ctors, The dehvered costs of the phosphate rock and sulfuric acid raw materials often account for more than 90% of the cost of producing NSP, thus the production cost varies considerably with plant location. Because the rock is richer in P2O5 than is the low analysis NSP product, NSP need not be produced near the phosphate mine. However, deUvery of sulfuric acid and shipment of product to market are important cost factors. Most United States NSP plants have been located east of the Mississippi river, with concentration in the southeastern and extreme southern parts of the country where the largest use of the product has occurred. Production and use of the product also has been high in California. 

Ideally the historical record of stream water quaUty would extend back to a time when human activities in the drainage basin had no significant effects. This "pristine" condition had probably already passed in most U.S. rivers before any organized water quaUty studies were made, as concern about apparent stream pollution was commonly a motivating factor in starting such studies (see Water, pollution). 

Obstacles attend this new solution of the freshwater problem, which magnify those familiar to the chemical engineer in purifying other cheap or worthless raw materials into valuable products by treatment with chemicals or thermal or electrical energy. These obstacles are quite different from the previous main problem of water supply, ie, the factor of happenstance in finding a river or lake nearby or of making a fortunate geological strike. 

The split apparent in Fig. 11.9 was located along the top of the tube facing the steam inlet nozzle. This is one of several tubes in this area having similar longitudinal splits. Leakage of river water from these tubes resulted in feedwater contamination, which turned out to be a major factor in tube failures in the boiler. 

Table II summarizes analytical data for dissolved inorganic matter in a number of natural water sources (J3, 9, J 9, 20, 21). Because of the interaction of rainwater with soil and surface minerals, waters in lakes, rivers and shallow wells (<50m) are quite different and vary considerably from one location to another. Nevertheless, the table gives a useful picture of how the composition of natural water changes in the sequence rain ->- surface water deep bedrock water in a granitic environment. Changes with depth may be considerable as illustrated by the Stripa mine studies (22) and other recent surveys (23). Typical changes are an increase in pH and decrease in total carbonate (coupled), a decrease in 02 and Eh (coupled), and an increase in dissolved inorganic constituents. The total salt concentration can vary by a factor of 10-100 with depth in the same borehole as a consequence of the presence of strata with relict sea water. Pockets with such water seem to be common in Scandinavian granite at >100 m depth.

Figure 3. Dissolved oxygen profile of Willamette River, low flow conditions, 1973 with major DO controlling factors.

Rainwater and snowmelt water are primary factors determining the very nature of the terrestrial carbon cycle, with photosynthesis acting as the primary exchange mechanism from the atmosphere. Bicarbonate is the most prevalent ion in natural surface waters (rivers and lakes), which are extremely important in the carbon cycle, accoxmting for 90% of the carbon flux between the land surface and oceans (Holmen, Chapter 11). In addition, bicarbonate is a major component of soil water and a contributor to its natural acid-base balance. The carbonate equilibrium controls the pH of most natural waters, and high concentrations of bicarbonate provide a pH buffer in many systems. Other acid-base reactions (discussed in Chapter 16), particularly in the atmosphere, also influence pH (in both natural and polluted systems) but are generally less important than the carbonate system on a global basis. 

Fig. 9-8 Histogram of dissolved solids of samples from the Orinoco and Amazon River basins and corresponding denudation rates for morpho-tectonic regions in the humid tropics of South America (Stal-lard, 1985). The approximate denudation scale is calculated as the product of dissolved solids concentrations, mean armual runoff (1 m/yr), and a correction factor to account for large ratios of suspended load in rivers that drain mountain belts and for the greater than average annual precipitation in the lowlands close to the equator. The correction factor was treated as a linear function of dissolved solids and ranged from 2 for the most dilute rivers (dissolved solids less than lOmg/L) to 4 for the most concentrated rivers (dissolved solids more than 1000 mg/L). Bedrock density is assumed to be 2.65 g/cm. (Reproduced with permission from R. F. Stallard (1988). Weathering and erosion in the humid tropics. In A. Lerman and M. Meybeck, Physical and Chemical Weathering in Geochemical Cycles," pp. 225-246, Kluwer Academic Publishers, Dordrecht, The Netherlands.)...

Gibbs, R. J. (1967). The geochemistry of the Amazon River system Part 1, The factors that control the salinity and composition and concentration of suspended solids. Geol. Soc. Am. Bull. 78,1203-1232. 

All the factors mentioned in the previous sections play a role in the movement of metals through their overall biogeochemical cycle injection into the atmosphere, deposition onto land or water surfaces, transport via rivers and... 

The transport rate of mercury flowing from the land to the oceans in rivers has been increased by a factor of about three by human activity. While the increased rate is still relatively less important than the total transport of Hg through the atmosphere, it can represent a significant stress on the exposed organisms, particularly since the increased flux is unevenly distributed. That is, human activity has created local environments where the transport of mercury or its concentration in a river or estuary is many tens of times higher than background levels. 

Fig. 4 Predicted versus observed summer Anoxic Factor (AF) in (a, b) Foix Reservoir (Spain), (c, d) San Reservoir (Spain), (e, f) Brownlee Reservoir (USA), and (g, h) Pueblo Reservoir (USA). The results have been arranged to place the systems along a gradient of relative human impact (Foix Reservoir at the top, Pueblo Reservoir at the bottom). Predictions are based on linear models using different independent variables (in brackets) Inflow = streamflow entering the reservoir during the period DOCjjiflow = mean summer river DOC concentration measured upstream the reservoir CljjjAow = mean summer river CU concentration measured upstream the reservoir and Chlepi = mean summer chlorophyll-a concentration measured in the epilimnion of the reservoir. The symbol after a variable denotes a nonsignificant effect at the 95% level. Solid lines represent the perfect fit, and were added for reference. Modified from Marce et al. [48]...

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