Estuaries trace metals

In estuaries trace metal chemistry intensive studies have been devoted to the distribution of heavy metals between dissolved and suspended matter phase, the special influence of phytoplankton population and the complicated heavy metal concentration regulation in the estuarine water column affected by the salinity gradient and resuspension and solubilization phenomena. Detailed long-term studies are investigating the situation and its seasonal dependence in various parts of the Oosterscheldt in connection with effects exerted by the completion of the Dutch Delta Plan[42,43,44]. The influence of the dry and wet season have been studied in an African tropical estuary[44]. 

Watling, H.R. and R.J. Watling. 1976. Trace metals in oysters from Knysna Estuary. Mar. Pollut. Bull. 7 45-48. 

Bordin, G., J. McCourt, and A. Rodriguez. 1994. Trace metals in the marine bivalve Macoma balthica in the Westerschelde estuary, the Netherlands. Part 2 intracellular partitioning of copper, cadmium, zinc and iron — variations of the cytoplasmic metal concentrations in natural and in vitro contaminated clams. Sci. Total Environ. 151 113-124. 

Jiann, K.T. and B.J. Presley. 1997. Variations in trace metal concentrations in American oysters (Crassostrea virginica) collected from Galveston Bay, Texas. Estuaries 20 710-724. 

Scoullos, M., M. Dassenakis, and C. Zeri. 1996. Trace metal behaviour during summer in a stratified Mediterranean system the Louros estuary (Greece). Water Air Soil Pollut. 88 269-295. 

Sanders, J.G., G.F. Riedel, and G.R. Abbe. 1991. Factors controlling the spatial and temporal variability of trace metal concentrations in Crassostrea virginica (Gmelin). Pages 335-339 in M. Elliott and J.P. Ducrotoy (eds.). Estuaries and Coasts Spatial and Temporal Comparisons. ECSA Sympos. 19 (Univ. Caen, France, 1989). Olsen Olsen, Fredensborg, Denmark. 

The data presented in Table 11.1 indicate that the fluvial gross river flux is the major source of trace metals to the oceans and that most of this flux is in particulate form (fluvial gross particulate flux). But the majority of this particulate flux is trapped within estuaries, primarily via settling, and, hence, is not released into the open ocean. As a result, the fluvial net particulate flux is only about 10% of the fluvial gross particulate flux. In seawater, most of this particulate metal remains in solid form due to low solubilities. The particulate metals eventually settle to the seafloor and are subsequently buried in the sediments. In the case of iron, a small fraction of the particulate pool does dissolve. In the surface waters, solubilization of particulate iron can provide a significant amount of this micronutrient to the phytoplankton. 

Most cation exchange occurs in estuaries and the coastal ocean due to the large difference in cation concentrations between river and seawater. As riverborne clay minerals enter seawater, exchangeable potassium and calcium are displaced by sodium and magnesium because the Na /K and Mg /Ca ratios are higher in seawater than in river water. Trace metals are similarly displaced. 

Fig. 6.4 Calculated, estimated, or apparent salting out constants for various chemicals (a) selected aromatic compounds, (b) selected aliphatic compounds, (c) natural or surrogate hgands, (d) anthropogenic ligands, (e) sediment organic matter (SOM), (f) transition metal complexes, (g) trace metal complexes in the Mersey Estuary. Reprinted with permission from Turner A, Martino M, Le Roux SM (2002) Trace metal distribution coefficients in the Mersey Estuary UK Evidence for salting out of metal complexes. Environ Sci Technol 36 4578-4584. Copyright 2002 American Chemical Society...

Tsai WT, Lai CW, Hsien KJ (2003) Effect of particle size of activated clay on the adsorption of paraquat from aqueous solution. J Coll Interface Sci 263 29-34 Turner A (1996) Trace-metal partitioning in estuaries Importance of salinity and particle concentration. Marine Chemistry 54 27-39... 

Loring, D.H., Dahle, S., Naes, K. et al. (1998) Arsenic and other trace metals in sediments from the Kara Sea and the Ob and Yenisey estuaries, Russia. Aquatic Geochemistry, 4(2), 233-52. 

The mixture of organic constituents in the marine environment is extremely complex. Their origin is partly terrigenuous many compounds are produced in the marine environment itself. The different sources and their relative importance for the complexation of trace metals in estuaries, coastal seas and open ocean are riverine input, runoff from the coastal zone, resuspension, import of water mases, atmospheric input and in situ biological production. 

Theoretically in rivers and estuaries under severe trace metal pollution stress the same situation (M > L) might occur. In this case the limit to the possible "negative" CCcu is determined by the actual degree of contamination (Fig. 7 e). 

Duinker, 3.C. and Nolting, R.F., 1977. Dissolved and particulate trace metals in the Rhine estuary and the southern Bight. Mar. Poll. Bull., 8 65-71. 

Elbaz-Poulichet, F., Huang, W.W., 3ednacak-Biscan, 3., Martin, 3.M. and Thomas, A.3., 1982. Trace metal behaviour in the Gironde estuary the problem revisited. Thalassia 3ugoslavica, 18 61-96. 

Church, T.M., Tramontano, 3.M. and Murray, S., 1984. Trace metal fluxes through the Delaware Estuary. Int l. Council for Exploration of Sea (ICES) Symposium "Contaminant Fluxes through the Coastal Zone", Nantes, France, May, 1984. 

Phillips, D.J.H. 1994. Macrophytes as biomonitors of trace metals. In KJ.M. Kramer (ed.), Biomonitoring of Coastal Waters and Estuaries, pp. 85-103. Boca Raton, FL CRC Press. 

Ruiz, J.M. and J.I. Saiz-Salinas. 2000. Extreme variation in the concentration of trace metals in sediments and bivalves from the Bilbao estuary (Spain) caused by the 1989-90 drought. Mar. Environ. Res. 49 307-317. 

Mouneyrac, C., C. Amiard-Triquet, J.C. Amiard, and P.S. Rainbow. 2001. Comparison of metallothionein concentrations and tissue distribution of trace metals in crabs (Pachygrapsus marmoratus) from a metal-rich estuary, in and out of the reproductive season. Comp. Biochem. Physiol. Part C 129 193-209. 

Baeyens, W. 1998. Evolution of trace metal concentrations in the Scheldt estuary (1978-1995). A comparison with estuarine and ocean levels. Hydrobiologia 366 157-167. 

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