Sediments in eight types of mangroves were sampled in the Leizhou Peninsula. Heavy metals were analyzed to investigate the effects on metal distribution of mangrove communities, to evaluate contamination levels, identify sources and relationships between the two. Results showed that mangrove communities have effects on most heavy metal distributions in sediments, especially in the sediment with...

We report a synchronous increase in accumulation of reduced inorganic sulfur since c. 1980 in sediment cores from eight of nine lakes studied in the Canadian Arctic and Svalbard (Norway). Sediment incubations and detailed analyses of sediment profiles from two of the lakes indicate that increases in sulfur accumulation may be due ultimately to a changing climate. Warming-induced lengthening of ...

The geochemical processes of mercury in Dongfeng (DF) and Wujiangdu (WJD) reservoirs, which were constructed in 1992 and 1979, respectively in Wujiang River, which is the upper branch of Yangtze River were investigated. One sampling site was chosen up river of 1 km from the dam for each reservoir. Three sampling campaigns were conducted at these sampling sites in December 2003, April 2004 and J...

Natural loss of hydrocarbons was often low from mussel (Mytilus trossulus) beds (which were typically not cleaned after the Exxon Valdez oil spill), thus this habitat remained a long-term source of oil. Consequently, experimental restoration of nine contaminated beds was attempted in 1994; mussels were removed, contaminated surface sediment was replaced (33 metric tons), and original mussels we...

Surface sediment samples were collected from the Canon River mouth, Taiwan and analyzed for polycyclic aromatic hydrocarbons (PAHs). Total PAHs concentrations varied from 337 to 1,252 ng/g dry weight, with a mean concentration of 827 ng/g dry weight. The spatial distribution of PAHs reveals that the PAHs concentration is relatively high in the river mouth region, and gradually diminishes toward...

Some 43 samples collected from surficial sediments of Semnan Province (Alborz zone) and NE Isfahan Province (Central Iran zone) were analyzed, for constrains on provenance. Sand fraction were analyzed by XRF analyzer Philips Model PW 2450 in the laboratory of the Geology Survey Iran (GSI). Precision was 0.01%. Furthermore, 8 selected sediment samples and 8 samples from rock units from surroundi...

Bioturbation is one of the most widespread forms of ecological engineering and has significant implications for the structure and functioning of ecosystems, yet our understanding of the processes involved in biotic mixing remains incomplete. One reason is that, despite their value and utility, most mathematical models currently applied to bioturbation data tend to neglect aspects of the natural...

Introduction To employ improved countermeasures against PCB sources and to reduce the risk to aquatic biota, it is important to identify sources and migration pathways and ascertain their contribution to PCB pollution . Thus, a wider range of studies is required to identify potential PCB sources in the environment. The objective of this study is to identify PCB pollution sources affecting Tokyo...

-Putrefactive hydrogen sulfide production in the upper 4 cm of sediment in two small freshwater and eutrophic Southeast Michigan, U.S.A., lakes ranged from 0.13 to 1.51 with an average of 0.46 mg S l-~ day-~. Sulfate reductive production of hydrogen sulfide at the same sites ranged from 0.7 to 3.2 with an average of 1.54 mg S 1~ dayt. Putrefactive hydrogen sulfide production represented 5.1-53°...

Oxygen demand in river substrates providing important habitats for the early life stages of aquatic ecology, including lithophilous fish, can arise due to the oxidation of sediment-associated organic matter. Oxygen depletion associated with this component of river biogeochemical cycling, will, in part, depend on the sources of such material. A reconnaissance survey was therefore undertaken to a...