Heavy Metals In Suspended Matter Research Articles

Assessment of heavy metal pollution in water and sediments in the red river delta (Vietnam)

The paper studied the features of distribution of main heavy metals in the water-bottom sediments system in the Red River Delta (Vietnam). The tasks were to determine the flow of heavy metals, to study the adsorption processes of heavy metals in suspended matter and burial in bottom sediments. The studies were carried out during the main hydrological seasons of 2014 – 2016 years at 6 stations of main branches of the river for 8 basic heavy metals (Cu, Pb, Zn, Hg, Cd, As, Cr and Fe). Each year, the total flow of heavy metals entering the top of the delta was 98.8 thousand tons. The total flow of all heavy metals differed by hydrological seasons and by watercourses. In general, 1.76% - 16.25% of the flow of heavy metals accumulated throughout the year, the highest accumulation rates are for lead, iron and zinc. In the branches Ba Lat, Tra Ly, Ninh Co, due to the decrease in flow rates, an intensive process of the accumulation of suspended substances and sorbed heavy metals was observed.

Determination of heavy metals in suspended matter in the storage lake ?Bitterfelder Muldestausee?

Dissolved and particulate trace elements have been determined in 400 samples of both the inflow and the outflow waters of the storage lake “Bitterfelder Muldestausse” in order to investigate the sedimentation of 22 elements transported by the highly polluted Mulde River, an affluent of the river Elbe. Inductively coupled plasma mass spectrometry (ICP-MS) has been used to analyse filtered water samples because of its multielemental capabilities, the excellent detection limits, the wide linear calibration range and the high speed of analysis. A special leaching procedure has been employed for the very low amounts of the suspended matter collected from each water sample. The dissolved material has been also analysed by ICP-MS. Testing of the procedure employed by the analysis of a standard reference material (SRM BCR 146) and use of the standard addition method has resulted in both a good precision (1–7%) and accuracy. Despite the wide variation in the composition of the suspended matter samples the concentrations of the heavy metals in sediment samples and in the suspended matter have been found to be comparable. A balance of sedimentation has been calculated based on the mean values of concentrations of all elements investigated in both the water and suspended matter samples of the inflow and outflow. Results from this first study show that the storage lake acts as a sedimentation trap for Zn, Cu, Pb, Ni, Cr, Cd, U and Co.

Dual filtration effect of geochemical and biogeochemical processes in the Changjiang Estuary

Dissolved nutrients (NO 3 − , PO4 3−, SiO3 2−) and oxygen, chlorophyll- a, pH, and Eh were measured on board during a cruise in August 1988 in the Changjiang Estuary region. Heavy metals, organic matter and carbonate contents were analyzed in laboratory. The results show that geochemical processes in the Changjiang Estuary have dual filtration effect: on the one hand geochemical filtration effect, reflected by ferromanganese oxide flocculation and sedimentation, occurs near the turbidity maximum, and leads to enrichment of heavy metals in suspended matter and sediments; on the other hand biogeochemical filtration, reflected by nutrients consumption, organic matter and carbonate sedimentation and enrichment of trace elements in suspended matter, occurs outside the plume water front. The biogeochemical filtration affects the environmental conditions; the dissolved oxygen and pH increase, in surface water and decrease in bottom water. The biogeochemical filtration effect outside the plume front is more important than the geochemical filtration effect near the turbidity maximum.

Recent influence of man on the Ebro margin sedimentation system, northwestern Mediterranean Sea

Man's recent activities, such as construction of reservoirs, dams and irrigation channels, have changed the natural dynamics of the Ebro margin sedimentation system. The amount of sediment supplied by the Ebro river is presently less than 5% of the amount supplied 50–60 years ago. Suspended sediment supplied by the river at the present time has a higher proportion of clay minerals than before the construction of the dams and reservoirs. At present, only the finer particles escape the dams, leaving the remaining sediment and apparently a large proportion of heavy metal inputs coming from inland cities and industries trapped behind them. In the lower part of the river, heavy metal pollution in the suspended matter is relatively low. Heavy metal anomalies in the shelf muds suggest that present-day sedimentation is restricted mainly to the proximal mud-belt area, near the mouth of the river. Abnormally high concentrations of heavy metals in suspended matter have been detected at the shelf break and on the upper continental slope of the Ebro system. These polluted particles come from rivers and cities located north of the Ebro mouth and are transported by the general southward flow along the slope. Some pollutants can be used as tracers for particle dynamics on the Ebro margin. The present supplies and fluxes of suspended sediment are significantly different from those which occurred before management of the river and coast began.

汚濁感潮河川における底泥の巻き上げと懸濁態リン・重金属元素の挙動

Concentrations of phosphorus and heavy metals in water and suspended matter (SM) were examined in a polluted tidal river during tidal sediment transportation.The increases in concentrations of phosphorus and heavy metals in the Shonai River water following sediment transportation were attributed mainly to increases of phosphorus and metals in particulate form. Among various forms of phosphorus and heavy metals in SM, hydroxylamine-acetic acid (HA) soluble phosphorus and metals and hydrogen peroxide (HO) soluble phosphorus, whose concentrations in SM varied with the organic contents, were thought to be easily movable. Relationships among parameters suggested that the phosphorus and metals were mainly attached or adsorbed onto organic matter (HO soluble phosphorus, HA soluble zinc, copper, and lead), or adsorbed on iron hydroxide (HA soluble phosphorus). Their concentrations in SM decreased when sediment transportation was frequent, and were higher after the long meteorologically stable days compared to just after a storm. Thus, it was suggested that the movable phosphorus and heavy metals were lost partially from SM during the stage in which they scaled onto the bottom, but during meteorologically stable days, were more liable to be accumulated in bottom sediments owing to the fact that supply was greater than loss. Because of the considerable reduction to soluble form, manganese did not accumulate in SM or bottom sediments in the semireductive environment under study.