Contamination Of Bottom Sediments Research Articles

Metals Associated with Suspended Sediments in Lakes Erie and Ontario, 2000–2002

Sediment traps were deployed in the three major basins of Lake Erie, and the central (Mississauga) basin of Lake Ontario, and refurbished seasonally over the period 2000-2002. In Lake Ontario, sediment down-flux rates and corresponding contaminant down-flux rates were highest in winter during periods of unstratified thermal conditions, and generally increased with depth due to the influence of resuspended bottom sediments during all sampling periods. Lake Ontario suspended sediments exhibited the highest concentrations of metals; concentrations of mercury and lead frequently exceeded guideline values for bottom sediments. Contaminant levels in Lake Ontario suspended sediments were similar to concentrations in bottom sediments in the same area. There was a spatial trend toward higher suspended sediment metals concentrations from the eastern basin to the western basin of Lake Erie, which is similar to the trend in bottom sediment contamination. In the eastern basin of Lake Erie, which is the deepest area of the lake, there was no trend in down-flux rate with depth in 2001; however, down-flux rates increased with depth in 2002. Suspended sediments in the western basin of Lake Erie were determined to be largely resuspended bottom sediments; all western basin samples collected in the study exceeded the guideline value for mercury (0.486 microg/g).

Polychaete taxocenes variability associated with sediment pollution loading in the peter the great bay (the East Sea/Japan Sea)

Variations in species diversity and abundance of polychaete taxocenes that occurred in 1980–1989 under different contamination levels of bottom sediments were studied in three areas of Peter the Great Bay. The most polluted area was shown to be the Golden Horn Inlet where contaminant contents in the bottom sediments exceed the threshold values of negative biota alterations. Amursky Bay is characterized by a moderate level of contamination, while Ussuriysky Bay has the lowest level of contamination. Pollutant contents vary considerably within the same areas and their separate patches are polluted differently. An integral index characterizing the contamination of bottom sediments is proposed. This index is an average grade of the rank value of contaminant contents in sediments. The index was used to compare the contamination level and data on polychaete species diversity and abundance. The highest species diversity of polychaetes is found in the least affected zones. Monotonous decrease of the species number, as well as decrease in the indices of diversity and evenness, is correlated with pollution level increases. Significant growth of the average polychaete biomass and polychaete density is observed in the case of an increase of contamination from low to moderate levels. Conversely, the biomass and abundance of polychaetes decline following an increase in contamination.

Sediment quality guidelines and assessment: overview and research needs

Under the Clean Water Act (CWA), the EPA is responsible for protecting the chemical, physical, and biological integrity of the nation’s waters. Toxic contaminants in bottom sediments of the nation’s lakes, rivers, wetlands and coastal water create the potential for continued environmental degradation, even where water column contaminant levels comply with established water quality criteria. In response, EPA has developed an Agency-wide Contaminated Sediment Strategy to address the problem of contaminated sediments. One key feature of this strategy is the development of Sediment Quality Guidelines (SQGs). SQGs would be used to assess the extent of sediment contamination, or to implement measures designed to limit or prevent additional contamination. A number of specific technical approaches for the development of SQGs that are based on theoretical and empirical foundations have been proposed, including effects-based correlative approaches, equilibrium partitioning, and consensus using a combination of approaches. While each have their own advantages and limitations, any SQG must consider the bio-availability of contaminants in the sediment and the ecological realism associated with the implementation. Therefore, it is clear that the implementation of any SQG will incorporate biological testing. Based on the current state of the science, EPA will likely proceed with the establishment of formal SQGs which will rely heavily on the equilibrium partitioning (EqP) approach. There are a number of significant research needs that will need to be addressed as the EqP approach is implemented, including sediment quality modeling, sediment toxicity identification evaluations, studies that address bio-availability, studies that address the relative importance of exposure via sediment ingestion or ingestion of contaminated benthos, toxicological demonstrations of applicability of any SQGs, field verification, extension of the non-ionic mixture models to non-PAH compounds, and the establishment of toxicological databases (with benthic organisms) for standard toxicity endpoints.

Invertebrates as Monitors of Polymetal Contamination of Bottom Sediments

Invertebrates as Monitors of Polymetal Contamination of Bottom Sediments

Contamination of bottom sediments in kola bay, Russia

A team of Russian and Norwegian scientists investigates contamination of Kola Bay in the Barents Sea as a result of industrial and military activity and other causes. The sources and levels of concentration of petroleum products, chlororganic pesticides, and heavy metals in the bottom deposits of the bay are described and analyzed.

Radiochemical contamination of bottom sediments of some natural and artificial lakes of Middle East Poland

An investigation of the presence of some radioactive isotopes in the bottom sediments of two lakes, Piasecmo and Magluchowskie (Middle East of Poland) has been performed. Similar measurements were done at the Zalew Zemborzycki artificial water reservoir, filled up few years after the most intensive period of atmospheric nuclear explosions. It was estimated, that the concentration of radionuclides, especially of aaificial origin was much greater in natural lakes than in examined artificial one. That testifies for an accumulation of radioactive substances on the bottom of the water tanks. The confirmation of this thesis may be the fact, that 85% of 137Cs detected in Zalew Zembor'zycki comes from Chemobyl fallout while in natural lakes this isotope amounts only to 56-60%. Other isotopes, such as 210pb, 226Ra, and 224Ra'were detected in significant amounts. The radioactivity of 239'240pu isotopes reaches 2.2-2.6 Bq/kg for the lakes and 0.7 for Zalew Zemborzycki. The 238pu to 239,240pu ratio suggests, that detected plutonium comes from world fallout.

Ground-water, surface water, and bottom-sediment contamination in the O-field area, Aberdeen Proving Ground, Maryland, and the possible effects of selected remedial actions on ground water : D. A. Vroblesky, M. M. Lorah & J. P. Oliveros, US Geological Survey Water-Supply Paper, 2399, 1995, 95 pp

Ground-water, surface water, and bottom-sediment contamination in the O-field area, Aberdeen Proving Ground, Maryland, and the possible effects of selected remedial actions on ground water : D. A. Vroblesky, M. M. Lorah & J. P. Oliveros, US Geological Survey Water-Supply Paper, 2399, 1995, 95 pp

Particle pathways of Niagara river water in Lake Ontario affecting bottom sediment contamination

Particle pathways of Niagara river water in Lake Ontario affecting bottom sediment contamination

Desorption during resuspension events: Kinetic v. equilibrium model

The spills and release of hydrophobic organic chemicals (HOCs) into waterbodies have resulted in the contamination of bottom sediments. When these sediments are resuspended by runoff events or by dredging, particulate-phase contaminants desorb to the water phase. Equilibrium between the particulate phase and the dissolved phase is usually assumed for most modelling applications regardless of time scale. For well mixed systems in which chemical transport is not limited by mass transfer between the bulk water phase and sediment aggregates, an intraparticle diffusion model can be applied to estimate the time required for various HOCs to reach an equilibrium state between dissolved and particulate-phase concentrations. Calculations from this model show that total equilibrium time scales cover a wide range, from less than a day to a few hundred days. This study compares predicted suspension times for sediments of various sizes with expected equilibration times for desorption. This comparison indicates that the equilibrium assumption is not valid for a wide range of parameter values typical of natural systems. In particular, compounds with high partition coefficients, greater than about 104 mL g-1, will have minimum equilibration times of at least one to ten days. This is likely to be greater than the expected resuspension time.

Heavy metal transport in the Acarí‐São João de Merití River System, Brazil

Abstract Discharge of heavy metals from the Acari‐Sao Joao de Meriti River System into Guanabara Bay and the physico‐chemical mechanisms involved in the transport of these pollutants to the sea are evaluated. Determination of Hg, Cd, Pb, Zn, Mn, Fe, Cr, Cu and Ni concentrations by atomic absorption spectrophotometry were carried out for water, suspended particulate matter and bottom sediment samples. Transport of heavy metals occurs primarily via the particulate phase where mobile forms of metals prevail. Contamination of bottom sediments are indicated for Hg, Cd, Pb, Zn, Cu and Cr.

Setting of ecological standards for radioactive contamination of bottom sediments

Setting of ecological standards for radioactive contamination of bottom sediments

Bottom sediment contamination in the Bay of Naples, Italy

The nearshore sediments in the Bay of Naples show a buildup of organic carbon and increased levels of lead, copper and chromium as a result of discharge of domestic and industrial waste water. Twenty to twenty-five square kilometres of bottom area have been contaminated by the buildup of anoxic muds with elevated heavy metal concentrations.