Sediments dated sediment cores

Sediment pollution. The concentrations of pollutants in the dated sediment cores have been determined in our laboratory by atomic absorption spectrophotometry (AAS). Donazzolo et al. (15) and Pavoni et al. (16) reported mainly heavy metal concentrations. Marcomini et al. (17) and Pavoni et al. (18) discussed the concentration profiles of organic pollutants such as chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. 

Kanunan NC, Engstrom DR. 2002. Historical and present fluxes of mercury to Vermont and New Hampshire lakes inferred from Pb dated sediment cores. Atmos Environ 36 1599-1609. 

Lockhart WL, Wilkinson P, Billeck BN, Danell RA, Hunt RV, Brunskill GJ, DeLaronde J, St. Louis V. 1998. Fluxes of mercury to lake sediments in central and northern Canada inferred from dated sediment cores. Biogeochemistry 40 163-173. 

In a later study in the Venice lagoon, a dated sediment core was analysed [4]. Seven separate layers were analysed, dating from 1972 back to 1910. 

Zegers BN, Eewis WE, Boon JP. 2000. Eevels of some polybrominated diphenyl ether (PBDE) flame retardants in dated sediment cores. Organohalogen Compounds 47 229-232. 

Geochemical analyses of dated sediment cores can also provide important information on past environmental changes (e.g., ref. 6). However, the geochemical record of many water chemistry variables of interest (such as lake-water pH, total phosphorus, monomeric aluminum, and salinity) is often... 

Mercury Fluxes and Sediment Records. Our calculations of lakewide Hg fluxes from more than 80 dated sediment cores from seven small headwater lakes reveal a regionally consistent increase in Hg inputs from preindustrial times to the present the modern Hg flux to each of these lakes is about 3.7 times that of the early 1800s. Such increases are typical of that reported in other investigations of lake sediments from remote or rural sites in eastern North America (3, 6, 7,10, 23). Most researchers have concluded that the increase is anthropogenic and that the Hg must be transported through the atmosphere and deposited on the lake and its terrestrial catchment. 

Methods for dating sediment cores using 210Pb and 137Cs were similar to those described by Robbins and Edgington (34). 137Cs content was de-... 

Gaus C, Brunskill GJ, Weber R, Papke O, Muller JF (2001) Historical PCDD Inputs and Their Source Implications from Dated Sediment Cores in Queensland (Australia). Environ Sci Technol 35 4597... 

Profiles of toxaphene in dated sediment cores have been used to infer historical deposition and degradation of toxaphene in Lake Superior and the nearby inland lakes [50,94,95], Michigan [94,96] and Ontario [94,97-99]. There is sufficient detail from these studies to infer the history of inputs of toxaphene... 

Table 9 Concentrations and fluxes and year of maximum deposition of toxaphene in dated sediment cores from the Great Lakes... 

Swackhamer D, Engstrom D (2000) Toxaphene concentrations in dated sediment cores from a holding pond for kraft bleach effluent. Unpublished data. School of Public Health, University of Minnesota, MN... 

There have been four studies of PBDEs in sediment from the Great Lakes all have used dated sediment cores to determine the history of PBDE deposition. The studies by Song et al. [46-48] used 14 sediment cores from all of the lakes and that of Zhu and Hites [22] used one sediment core from northern Lake Michigan and one from eastern Lake Erie (see above). All cores were dated using the well-known lead-210 method. 

Mai, B.X., Zeng, E.Y., Luo, X.J., Yang, Q.S., Zhang, G., Li, X.D., Sheng, G.Y., Fu, J.M., 2005b. Abundances, depositional fluxes, and homologue patterns of polychlorinated biphenyls in dated sediment cores from the Pearl River Delta, China. Environ. Sci. Technol. 39, 49-56. 

Heim, S., M. Ricking, J. Schwarzbauer, and R. Littke. 2005. Halogenated compounds in a dated sediment core of the Teltow canal, Berlin Time related sediment contamination. Chemosphere 61 1427-1438. 

Two groups, one in Switzerland and the other in Sweden, have used age-dated sediment cores from peat bogs and natural lake sediments to record the history of atmospheric Pb pollution dating back to several thousand years. 

Because of the tendency of HCs to associate with particles, suspended sediment is likely to be the vehicle for the vast majority of the transport of HCs. Once the sediment settles out of flow and settles to the floor of the receiving water body, it can represent a threat to the ecological community. Benzo[a]pyrene, for example, was not detected in any of 100 storm-event samples in residential sites in the Dallas-Fort Worth area and was detected in less than 5% of samples from commercial and industrial sites (Raines et al., 1997). Yet concentrations of benzo[a]pyrene have increased 20-fold in the Dallas-Fort Worth area, coincident with urban development, based on an age-dated sediment core from White Rock Lake in Dallas (Van Metre et al., 2000). 

Figure 1. Box model for the calculation of Mn redox cycling near the sediment-water interface. Sedimentation rates are measured with sediment traps. The burial rate Sh is estimated from dated sediment cores. In situ sampling techniques (flux chambers and peepers) are used to quantify the diffusive flux across the sediment-water interface FS6. The resuspension rate R is estimated from the increase in the mass flux of settling material between the 81- and 86-m horizons.

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