Estuarine environments sediments

Removal to sediments. Removal of surface-reactive trace elements from the oceans readily occurs by adsorption onto settling particles, and this process is most pronounced in the typically high-energy, particle-rich estuarine environment. Particles are supplied by rivers, augmented by additions of organic material generated within the estuary. Also, floes are created in estuaries from such components as humic acids and Fe. The interaction between dissolved and colloidal species is enhanced by the continuous resuspension of sediments in... 

Cochran JK (1984) The fates of U and Th decay series nuclides in the estuarine environment. In The Estuary as a Filter. Kennedy VS (ed) Academic Press, London, p 179-220 Cochran JK (1992) The oceanic chemistry of the uranium - and thorium - series nuclides. In Uranium-series Disequilibrium Applications to Earth, Marine and Environmental Sciences. Ivanovich M, Harmon RS (eds) Clarendon Press, Oxford, p 334-395 Cochran JK, Masque P (2003) Short-lived U/Th-series radionuclides in the ocean tracers for scavenging rates, export fluxes and particle dynamics. Rev Mineral Geochem 52 461-492 Cochran JK, Carey AE, Sholkovitz ER, Surprenant LD (1986) The geochemistry of uranium and thorium in coastal marine-sediments and sediment pore waters. Geochim Cosmochim Acta 50 663-680 Corbett DR, Chanton J, Burnett W, Dillon K, Rutkowski C. (1999) Patterns of groundwater discharge into Florida Bay. Linrnol Oceanogr 44 1045-1055... 

The important forces involved in the adsorption of metals on to particles are attractive electrostatic or van der Waals forces. These concepts explain many of the properties of colloids with respect to the adsorption of contaminants or ion-exchange factors and the aggregation of the colloids into larger particles. These larger particulates may then descend the water column to the sediment. This occurs most notably in estuarine environments, as increases in salinity lead to estuarine silting. Binding of electrolytes to hydrophobic colloids is often used to facilitate their coagulation and precipitation. 

Spatial trends in LAS concentrations in marine and estuarine environments show clear relationships with the location of sampling points relative to point sources of wastewater discharges and a rapid rate of decrease is observed as one moves downstream from these. LAS tend to be degraded relatively rapidly in summer, whereas in winter a higher recalcitrance is observed. Sediments constitute the final sink of LAS that have not been degraded. 

On the other hand, two bottom sediment samples were collected from the Willamette River (Benton County) and Yaquina Bay (Newport), Oregon. These samples represent both fresh water and estuarine environments with slightly different degrees of organic matter compositions. 

Li et al. [323] studied the bacterial transformation of pyrene in an estuarine environment (Kitimat Arm, British Columbia, Canada), where they separated a metabolite (i.e., ris-4,5-dihydroxy-4,5-dihydropyrene) from the sediment and pore waters. The presence of this key metabolite from the dioxygenase-mediated transformation of pyrene [100, 186, 342], along with previous pyrene degradation studies using cultures isolated from the same sediment samples, suggested a possible in situ bacterial transformation of pyrene in the Kitimat Arm environment. 

Gearing PJ, Gearing IN, Pruell RJ, et al. 1980. Partitioning of no. 2 fuel oil in controlled estuarine ecosystems Sediments and suspended particulate matter. Environ Sci Technol 14(9) 1129-1136. 

The A. marina bioassay is routinely used in the UK, but only in more saline conditions (Thain and Bifield, 2001). The survival of this polychaete in our study was hardly affected by the sediments tested during the study, but the number of casts produced varied considerably (Table 6). Significant effects with the above sediment in vivo bioassays used here have been demonstrated in other studies, not only in Dutch harbour sediments, but also marine and estuarine environments (Matthiessen et ah, 1998 Kater et al., 2001 Stronkhorst, et al., 2003b). 

Later studies by investigators (Alberts ei al 1979) have shown lhai 1 >7Cs introduced into a watershed is attached to soil panicles, which arc removed by erosion and runoff. Some of the eroded soil panicles comprise he sediments of the catchment basins in the watersheds and act as "sinks for, 7Cs. Other investigators have reponed an almost irreversible fixation of this clement in clay imerlattice sites in freshwater environments, and. that it is unlikely that this nuclide will he removed from these sediments under normal environmental conditions other than by exposure to solutions ol high ionic strength, such as may occur in estuarine environments. Studies of 15 Cs have been important because ihe element can be introduced into a water system from a leak in a nuclear fuel element. These findings are reported in some detail by Alberts ct al. in Science, 203. 649-651 (1979). 

Scientists at die University of Maryland have found that sediment microflora (from Chesapeake Bay sediments) can produce dimethyitin and tiimetliyllin species from inorganic Sn(IV) compounds. Tlie results were consistent with a geocycle of tin proposed by Ridley et al. in 1977. The findings support the hypothesis that tin can be biotransformed in an estuarine environment,... 

The SQT procedure for contaminated sediments was originally proposed by Long and Chapman (1985), and subsequently refined by Chapman et ah (1987), Chapman (1990, 1996), Chapman et ah (1997, 2002) and Grapentine et ah (2002). Chapman (2000) summarises published SQT studies in marine, freshwater and estuarine environments in the following geographic areas North America, Europe, and Antarctica. Subsequent SQTs have included presently unpublished studies in Australasia and South America (Chapman, pers. comm.), and published studies in Europe (Hollert et ah, 2002a,b Beiras et ah, 2003 Lahr et ah, 2003 Riba et ah, 2004) and North America (Anderson et ah, 2001 Balthis et ah, 2002 Schmidt et ah, 2002). 

The main cause of sedimentation of particles in estuarine environments is aggregation [49]. Later, when the floes settle out they lose their identity and become part of the bottom sediment [49]. Therefore, when analyzing sediments, it is not a simple task to relate the size distribution in the sediment to the sizes, transport mechanisms, and behaviour of the particles before they were deposited. These waters tend to exhibit quite broad size distribution curves, although, if samples are collected and deflocculated, even flatter, broader distribution curves result, having smaller mode... 

Jones, T.W., Kemp, W.M., Stevenson, J.C., Means, J.C. (1982) Degradation of atrazine in estuarine water/sediments systems and soils. J. Environ. Qual. 11(4), 632-638. 

The preservation of organic matter in coastal and estuarine sediments is believed to be principally controlled by productivity, sedimentation accumulation rate, bottom water and sediment redox conditions, and sorption as a function of specific surface area of sediments (see review, Hedges and Keil, 1995). In this section the focus will be primarily on factors controlling preservation or organic matter in estuarine sediments the use of chemical biomarkers for historical paleo-reconstruction of past estuarine environments is discussed in chapter 15. 

Schubel, J.R. (ed.) (1972) Classification according to mode of basin formation. In The Estuarine Environment Estuaries and Estuarine Sedimentation, pp. 2-8, American Geological Institute, Washington, DC. 

A survey of rates of N release from sediments in ocean, coastal and estuarine environments is presented in Table 8.5 we note that this is not an exhaustive... 

---