River mouth

Figure 4 Measurements of (A) uranium aetivity ratios, UARs ( U U) and U eoneentrations (B) aeross a salinity gradient off the Amazon River mouth (1996). UARs were determined by thermal ionization mass speetrometry (TIMS) at Calteeh (D. Poreelli) U eoneentrations by ICPMS...

Figure 3.2. 8 C values of fossil browser apatites plotted against age for sites including Die Kelders, Klasies River Mouth I, Sterkfontein and Makapansgat. Enamel is represented by solid squares, bone apatite by solid circles. The mean value standard deviation for modem browsers, represented by dashed lines, has been shifted by +1.5%o as described in the text. Adapted from Lee-Thorp and van der Merwe (1987).

CROUP (11) Klasies River Mouth Cave lA (age >" before present) ... 

The results for all sites are given in Table 5.1, and are best considered by dividing sites into three groups according to isotopic nature of the matrix (i) sites with most isotopically emiched matrix carbonates (Die Kelders and Swartkrans), (ii) sites with rather less enriched carbonates (Klasies River Mouth and Makapansgat), and finally (iii) a site with depleted deposit values (Border Cave). This is summarized in Fig. 5.5. The division also fortuitously provides a range of age depths in two categories. As indicated in Table 5.1, many of these data have been published elsewhere, but the purpose for which they are considered in combination here has not been previously attempted. 

These sites have deposit carbonates slightly less enriched than the previous group -3.2 2.1%o at Klasies River Mouth (where matrix values are... 

Singer, R. and Wymer, J. 1982 The Middle Stone Age at Klasies River Mouth in South Africa. Chicago, University of Chicago Press. 

Several studies have examined the partitioning of U on particles and colloids. Results from detailed sampling and particle separation in the Amazon estuary shows that most of the uranium at the Amazon River mouth is associated with particles (>0.4 im) and that >90% of the uranium in filtered water (<0.4 im) is transported in a colloidal phases (from a nominal molecular weight of 10 000 MW up to 0.4 im) (Swarzenski et al. 1995 Moore et al. 1996). Mixing diagrams for uranium in different size fractions in the Amazon estuary reveal that uranium in all size fractions clearly display both removal and substantial input during mixing. 

Figure 4. The uranium concentration in unfiltered water, 0.2 gm and 3 kD filtered water in river water from the Kalix River mouth and samples from the low salinity estuarine zone (0-3). Data plotted against conductivity (although the salinity scale is not defined below 2, a tentative scale is indicated). The lines represent the best fit for each fraction in the estuary. The data from the Kalix river mouth represent the river water component, which show <10% aimual variation in concentration. The analytical errors are smaller than the symbols. Data from Andersson et al. (2001). Copyright 2001 Elsevier Science.

Figure 5. The in 0.2pm and 3 kD filtered water and colloids phase (3kD - 0.2pm) and particles (>0.2 pm) as well as material from sediment traps plotted versus conductivity in the low salinity zone (0-3) of the Kalix River estuary. The stippled area marks the reported annual range in at the Kalix river mouth, which show a substantial variation compared to the uranium concentration. Data from Andersson et al. (2001). Copyright 2001 Elsevier Science.

Fitchko J, Hutchinson TC. 1975. A comparative study of heavy metal concentrations in river mouth sediments around the Great Lakes. J Great Lakes Res 1 46-78. 

The river Ebro basin has a triangular shape, where the larger sides are the Iberian range and the Pyrenees, the two converging in the north-east (Fig. 1). In between, a depression increases in width from the west to the east. Just before the river mouth the Ebro crosses the Catalan Mountain Range. 

Sabater et al. [3] performed chemical and planktonic analyses at 31—43 sampling sites scattered along the main course of the Ebro (Fig. 1). Twenty-five sites covered from the upper reach down to the Ebro Reservoir to the reservoirs of Flix, Mequi-nenza and Ribaroja, while the other six were downstream up to 30 km from the river mouth. Samples were collected in June and October 2005 and 2006. Other surveys were completed in 2008 and 2009. Physical, chemical, and biological analyses were performed at all sites and were later related to the phytoplankton biomass. 

For example, 95 km upstream from the river mouth there is the Flix reservoir, where there are around 200,000-360,000 tons of industrial waste with a high concentration of heavy metals and organochloiines due to the activity of an chloro-alkali industry for more than half a century [11],... 

The studies revised in this chapter correspond to the last 125 km of the Ebro River, from the Riba-roja dam to the river mouth, plus about 100 km of one of the main Ebro tributaries the Cinca/Vero system (see map in Fig. 1 for location of the sites). This area is heavily dammed to regulate the river flow as well as to provide electric power and facilitate water captation for irrigation channels. Dams and overflow dams relevant for the studies revised here are shown in Fig. 1. 

Water Hyacinth. Water hyacinth (Eichornia crassipes Solms) has been killed by 0.1% solution of the alkanolamine salt of 2,4-D in Indonesia (54), or in the Philippines by the isopropyl ester in as low as 0.1% solutions (39). In the southern United States, 2,4-D has been widely used to kill this plant. This plant is of relatively minor importance in Puerto Rico. It tends to choke up river mouths and is removed to improve drainage. A single application of the isopropyl ester of 2,4-D has given excellent results on a small scale. 

There is also evidence that new clay mineral phases form. Comparisons of the clay phases carried down with a river with the clay phases deposited in the ocean outside the river mouth are suggestive but not altogether conclusive since it is hard to exclude completely the influence of rates of sedimentation, currents, etc. 

Fig. 7 PCDD/F homolog profiles in urban air particulates and surface sediments sampled from mid-Lake Michigan (1982), lower Lake Huron (1975, 1981), eastern Lake Erie (1981, 1983), and western Lake Ontario (1983) near the Niagara River mouth. Reproduced with permission from Czuczwa and Hites [20]. Concentrations of OCDD are given in the upper right hand corner (ppt = ngkg-1 dw)...

The results of the simulation experiment are given in Table 6.13. We can see that the average content of heavy metals across the full water area of the Arctic Basin stabilizes after 3-5 years. Under this stable regime, the concentration of heavy metals in compartments Qp U Op (river mouths and ports) is six times higher than in the Central aquatory and twice as high in Or U Op U Q.N (near-shore waters, the Bering Strait, and the southern boundary of the Norwegian Sea). The concentration of heavy metals in phytoplankton is 18% lower than in zooplankton and 29% lower... 

Menasveta, P., Cheevaparanapiwat, V., 1981. Heavy metals, organochlorine pesticides and PCBs in green mussels, mullets and sediments of river mouths in Thailand. Mar. Pollut. Bull. 12, 19-25. 

Eutrophication Processes in Coastal Systems Origin and Succession of Plankton Blooms and Effects on Secondary Production in Gulf Coast Estuaries, Robert J. Livingston Handbook of Marine Mineral Deposits, David S. Cronan Handbook for Restoring Tidal Wetlands, Joy B. Zedler Intertidal Deposits River Mouths, Tidal Flats, and Coastal Lagoons, Doeke Eisma... 

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