Environment coastal

Global uranium flux calculations have typically been based on the following two assumptions (a) riverine-end member concentrations of dissolved uranium are relatively constant, and (b) no significant input or removal of uranium occurs in coastal environments. Other sources of uranium to the ocean may include mantle emanations, diffusion through pore waters of deep-sea sediments, leaching of river-borne sediments by seawater," and remobilization through reduction of a Fe-Mn carrier phase. However, there is still considerable debate... 

If uranium is internally cycled in coastal environments or if the riverine delivery of U shows some variability, residence time estimates (regardless of their precision) cannot be sensitive indicators of oceanic uranium reactivity. Based on very precise measurements of dissolved uranium in the open ocean, Chen et alJ concluded that uranium may be somewhat more reactive in marine environments than previously inferred. Furthermore, recent studies in high-energy coastal environments " indicate that uranium may be actively cycled and repartitioned (non-conservative) from one phase to the next. 

Pyrene is a common PAH contaminant and may occur in drinking water. Chlorination of water with or without bromide that may be present in coastal environments has been examined. Both chlorinated and brominated pyrenes with halogen substituents at the 1,3-, 1,6-, and 1,8-positions were found, and could putatively be produced by reaction of pyrene with hypochlorous acid and hypochlorite (Hu et al. 2006). 

The complex interactions amongst geological, biological, and geochemical processes at the land-sea margin control the delivery and fate of radionuclides, contaminants, and other natural elements in coastal environments (Swarzenski et al. 2003). For many such constituents, there is at least a fundamental understanding of major source and sink functions and their potential estuarine transformation reactions. For example, rivers can be monitored quite easily for discharge rates into estuaries as well as for elemental... 

Pattenden NJ, McKay WA. 1994. Studies of artificial radioactivity in the coastal environment of northern Scotland A review. J Environ Radioact 24 1-51. 

L. K. Benninger, D. M. Lewis and K. K. Turekian, in Marine Chemistry in the Coastal Environment, ed. T. M. Church, ACS Symposium Series, no. 18, American Chemical Society, Washington, 1975,... 

Brinckman FE, Iverson WP (1975) In Church T (ed) Marine chemistry in the coastal environment. American Chemical Society symposium 18. American Chemical Society, Washington, DC... 

In coastal environment, detrital and authigenic Fe and Mn oxides, which accumulate in oxic surface sediments, play a pivotal role in determining the geochemical behaviour of arsenic (Mucci et al., 2000) and selenium (Belzile et al., 2000). Arsenic and selenium differ in their affinities for metal oxide surfaces. Although both adsorb onto iron oxides, arsenate (As(V)) adsorbs more strongly than arsenite (As(lll)), and selenite (Se(IV)) adsorbs more strongly than selenate (Se(VI)) (Belzile et al., 2000). 

Few data have been published on cationic surfactants in aquatic sediments. Levels from 3 to 67 mg kg-1 were determined in sediment samples from Rapid Creek [54] and 6-69 mg kg-1 concentrations were found in sediment samples from Japan [4]. DTD MAC was reported in digested sewage sludge at levels ranging from 0.15 to 5.87 gkg-1 [22]. Also, cationic surfactants were determined in urban coastal environments and they were reported as markers [18,55]. In our work, concentrations of BAC ranged from 23 to 206 p,gkg 1 in sediment samples from different rivers near to wastewater treatment plants,... 

Although a substantial body of data is available on the levels of linear alkylbenzene sulfonates (LASs) in rivers and estuaries, fewer studies have been conducted on their environmental behaviour, with reference to the mechanisms involved in their transport and to the reactivity they undergo. Studies of LAS in subterranean water and in the marine medium are scarce and have mainly been conducted in the last decade [2-6], coinciding with the development of new techniques of concentration/separation and analysis of LAS at ppb levels or less. Data on concentrations of sulfophenyl carboxylates (SPCs) are very scarce and the behaviour of these intermediates has hardly received any study. This chapter provides an overview of the current knowledge on behaviour of LAS and their degradation products in coastal environments. 

Several specific studies have been made on the LAS transport processes in a variety of different estuarine and marine environmental compartments (e.g. LAS removal by biodegradation and/or adsorption), including the flux of LAS from freshwater to a coastal environment [3,6, 29,40]. However, a complete study of LAS behaviour requires knowledge of their primary biodegradation intermediates, SPC, that have been detected in different laboratory tests [15,36,37], Their existence in fresh-water [2,13] and marine water [5] has been demonstrated recently. 

Although the marine environment is the final compartment receiving surfactants, few reports have considered seawater species. To the best of our knowledge, surfactants bioconcentration has been determined in marine algae [8], shrimp [51], mussel [51,66,69] and the stickleback [51]. Although experiments are increasingly being focused on the marine and coastal environments, further work is necessary to measure bioconcentration in these ecosystems. 

The matrices and sources of the sediments listed in Table 4.2 are sometimes unclear. Those that are known are highly weighted toward clastic (quartz- and aluminosilicate-rich) marine sediments from coastal environments. Some of these reference materials, such as MESS-3 (NRC-Canada), MAG-1 (USGS) and the Arabian Sea and Pacific Ocean samples (IAEA 315, and 368), could provide excellent examples of clastic marine sediment representing the main repositories of organic matter in the ocean (Hedges and Keil, 1995). The listed materials fail to include both open-ocean opal and carbonate oozes, as well as pelagic red clays. 

Reference materials that represent the primary deep-sea and coastal depositional environments and biological materials would solve many of the problems that radiochemists face in analysis of sediments from these settings. Radiochemists require reference materials comprising the primary end member sediment and biological types (calcium carbonate, opal, and red clay from the deep-sea and carbonate-rich, silicate-rich, and clay mineral-rich sediments from coastal environments and representative biological materials). Additional sediment reference material from a river delta would be valuable to test the release of radionuclides that occurs as riverine particles contact seawater. 

Following considerations based on usage information, physico-chemical properties, and persistence, a priority list of herbicides was established for the Mediterranean countries, i.e., France, Italy, Greece, and Spain ([168, 182, 183] Table 6). This list considers selected herbicides which can cause contamination of estuarine and coastal environments. The selection of pollutants has been based on the availability of usage data and the consideration of half-lives [182,183]. 

In the dynamic coastal environment, this would include changes in such factors as temperature, salinity, nutrients, and light. 

Several laboratory studies have contributed to our understanding of turbulent chemical plumes and the effects of various flow configurations. Fackrell and Robins [25] released an isokinetic neutrally buoyant plume in a wind tunnel at elevated and bed-level locations. Bara et al. [26], Yee et al. [27], Crimaldi and Koseff [28], and Crimaldi et al. [29] studied plumes released in water channels from bed-level and elevated positions. Airborne plumes in atmospheric boundary layers also have been studied in the field by Murlis and Jones [30], Jones [31], Murlis [32], Hanna and Insley [33], Mylne [34, 35], and Yee et al. [36, 37], In addition, aqueous plumes in coastal environments have been studied by Stacey et al. [38] and Fong and Stacey [39], The combined information of these and other studies reveals that the plume structure is influenced by several factors including the bulk velocity, fluid environment, release conditions, bed conditions, flow meander, and surface waves. 

Palumbo AV, Pfaender FK, Paerl HW. 1988. Biodegradation of NTA and m-cresol in coastal environments. Environ Toxicol Chem 7 573-585. 

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