Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 microg x g(-1) fluoranthene, but at the next higher treatment (108 microg x g(-1)) the number of worms found wa...

Recent Lake Tanganyika Hg deposition records were derived using C and excess Pb geochronometers in sediment cores collected from two contrasting depositional environments: the Kalya Platform, located mid-lake and more removed from watershed impacts, and the Nyasanga/Kahama River delta region, located close to the lake’s shoreline north of Kigoma. At the Kalya Platform area, pre-industrial Hg co...

approach of organic material anaerobic biodegradation and species of organic matter in sediment are discussed, and then a classifying method of the species is proposed on a new viewpoint. the pore water sediment oxygen demand (sod) numerical model in bottom sediment system is proposed originally, which differs from other advection-dispersion-sorption (ads) model in adding a sod-creating term. t...

industrial activities lead to an increase in heavy metal burden in rivers. sediment and algae (spirogyra sp.) samples were collected from the shoor river to investigate their heavy metal concentrations. dry and ashed samples of algae and sediment were digested using concentrated nitric acid. heavy metals (as, fe, zn and cr) concentration measured using an icp-oes instrument (perkinelmer, usa). ...

pollution of water and soils by heavy metals is an emerging problem in industrialized countries.the present study was conducted to investigate the heavy metals concentration in water and sedimentsamples from ship breaking sites of sitakunda to assess the potential ecological risk posed by heavy metalusing different methods. heavy metals concentration was analyzed by atomic absorption spectrosco...

Scour is a phenomenon that occurs as a result of natural erosion by ground water flow and transport of seabed material. In this research, scour around the legs of marine structures is simulated using the FLOW3D.V.9.3™ commercial software. The general scour model consists of two components, namely, the lift and thrust forces. The drag force, that is inserted to the structure, is a combination of...

Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition. However, redox-mediated reactions in the...

the behavior of suspended sediment during flood events is not only a function of energy conditions, i.e. sediment is stored at low flow and transported under high flow conditions, but also is related to the variations in sediment supply and sediment depletion. these changes in sediment availability result in so-called hysteresis effects. therefore, hysteresis pattern analysis is of great import...

One of the most important issues in water supply for agriculture or drinking is sediment control.Sedimentation in water conveyance channels reduces transmission efficiency. this study evaluated theefficiency of settling basin of Kamandan intake that is located in the village of Aligoodarz in Lorestanprovince. At first sample from water and sediment in inlet and outlet of settling basin in diffe...

sediment core samples can provide useful information about aquatic environment. sedimentation rate, climate changes and heavy metal concentration are among the most important studies that are carried out on sediment cores. in this study, a sediment core of 70cm with aim of metal concentration investigation is collected from central part of the zarivar lake in the vicinity of the marivan city in...