The concentrations, distribution, accumulation, and potential ecological risk of heavy metals (Cr, Cu, Zn, Ni, As, Pb, Cd, and Hg) in sediments from the Three Gorges Reservoir (TGR) tributaries were determined and studied. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of heavy metals ...

The earliest food producers in Africa were mobile pastoralists who left limited archaeological traces. As a result archaeologists studying the spread of food production in the region have difficulty distinguishing early pastoralists from hunter-gatherers with whom they interacted. This geo-ethnoarchaeological study contributes to the resolution of the problem through identification of sediments...

Biogeochemical processes mediated by microorganisms in river sediments (hyporheic sediments) play a key role in river metabolism. Because biogeochemical reactions in the hyporheic zone are often limited to the top few decimetres of sediments below the water-sediment interface, slow filtration columns were used in the present study to quantify biogeochemical processes (uptakes of O2, DOC, and ni...

Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant populat...

The concentrations of total polycyclic aromatic hydrocarbons (sigmaPAHs) and 15 individual PAH compounds in 20 surface sediments collected from four mangrove swamps in Hong Kong were analysed. sigmaPAH concentrations ranged from 356 to 11,098 ng g(-1) dry weight with mean and median values of 1992 and 1,142 ng g(-1), respectively. These values were significantly higher than those of marine bott...

The increasing use of magnetic parameters as a proxy for environmental change necessitates the understanding of processes that link magnetic properties of sediments, especially organic-rich lake sediments, and environmental change. To explore the magnetic mineralpaleoenvironment link, we have recovered a 14,000 yr mineral-magnetic record fromWhite Lake, a hardwater lake containing organicrich s...

The present study was carried out to investigate the adsorption and leaching behavior of Cu2+, Zn2+ and Pb2+ by sediments collected from the western banks of three different sectors along River Nile at Aswan governorate, Egypt. The feasibility of sediments for the removal of Cu2+, Zn2+ and Pb2+ from aqueous solutions was tested under the effect of three conditions (pH, initial metal concentrati...

The mineralogy and geochemistry of Paleocene shales and interbedded siltstones in the southwestern of Ahar town (NW Iran) were studied by optical microscopy, XRD, SEM, XRF, and ICP-MS techniques. The mineralogical composition, mainly characterized by calcite, quartz, feldspar, dolomite, muscovite, magnesiohornblende, chlorite, illite, montmorionite, palygorskite, and koninckite, suggests relati...

Bachmann et al. (2005) contend that a major fraction of flocculent sediments, a ‘‘fluid mud layer,’’ which has accumulated in Lake Apopka, Florida, since 1947, originated from sediment liquefaction of consolidated macrophyte-derived sediments. In addition, they contend that the underlying historic sediments are not only a major source of fluid mud, but also the source of organic matter for inte...

abstract spacing between check dams depends on the stream bed slope, effective height of check dams and slope of deposited sediments behind the check dams. the slope of deposited sediments is more important than the other two factors because of complications in the way of its occurrence and its measurement after several years of dam construction. this research presents the effective factors aff...