Heavy Metals In Stream Sediments Research Articles

Heavy metals in stream sediments: Effects of human activities

The content of 11 heavy metals in the sediments of a stream system was determined by atomic absorption analysis. Geochemical phases were investigated using a sequential extraction scheme, and bulk contents were assessed with a single HNO3 extraction. Certain heavy metals were associated with different geochemical phases. Co, Mn, and Ba concentrated primarily in the carbonate and Mn phases, while all the remaining metals concentrated in the Fe and remnant phases. Features located along the stream system influenced the content of heavy metals. Results from the geochemical phases indicated Cu, Pb, Zn, Cd and Ag were emitted by one landfill, while Cd, Ba, and Ag were emitted by a second landfill. A wastewater treatment facility appeared to emit Ni and Cu. A stream draining a reservoir and joining the study stream resulted in dilution of the heavy metals in the sediments. A populated area along the study stream appeared to emit Mn. The single HNO3 extraction procedure is quicker to perform than the sequential extraction but does not indicate the phase associations.

Heavy metals in stream sediments: Error versus concentration

A regional geochemical mapping program in southern Norway carried out by the Geological Survey of Norway is based on sampling of stream sediments at road/stream intersections. At each site two individual subsamples have been taken. The subsamples were treated independently during the chemical analysis. This procedure enables an estimation of the reproducibility of the element concentration at each sample site. The paper gives results for the average relative total, sampling and laboratory errors at various levels of metal concentration using data for HNO 3 -soluble Mn, Pb and Cu as examples. For Mn and Pb the relative total error reaches a minimum near the median concentration and increases toward both the high and low concentrations. For Cu the relative total and laboratory errors decrease with increasing concentration throughout the whole concentration range, while the sampling error is fairly constant. The results suggest that the models which are commonly used for error determination in geochemical data, are too simple as far as relationships between error and concentration are concerned.

Seasonal variations in the heavy metal concentrations of sediments influenced by highways of different traffic volumes.

The distribution of contaminating waste products, particularly heavy metals, to the roadside ecosystem is cause for considerable concern, due to both the documented toxicity of these metals at low concentrations and their accumulation by resident organisms. The elements of major concern are lead from gasoline engine exhsuts, nickel from both diesel fuel and lubricating oil, and cadmium and zinc from rubber tires. Lead has been correlated to traffic density in various components of the terrestrial ecosystem. Similar results were reported for nickel, cadmium, and zinc, as well as lead. Information concerning concentration of heavy metals in roadside aquatic ecosystems is very limited. To provide an initial assessment of contamination from this source, we determined seasonal concentrations of heavy metals in stream sediment as related to traffic density. Heavy metals entering the stream ecosystem in runoff are rapidly adsorbed to sediment, providing a stable indicator of local contamination. Analysis of seasonal change in the heavy metal load of the sediment provides insight concerning the importance of runoff relative to sediment-water interaction and uptake by other componenets of the system.