Alena Mudroch

Manual of physico-chemical analysis of aquatic sediments

Introduction, A. Mudroch, J.M. Azcue, and P. Mudroch Measurement of Physical Properties of Sediments, J.B. Percival and P.J. Lindsay Measurement of Eh and pH in Aquatic Sediments, P. Brassard Rapid and Cost-Effective Analysis for Aquatic Sediment Samples by X-Ray Fluorescence Spectrometry, K.F. Maley Determination of Trace Elements in Sediments, G.E.M. Hall Neutron Activation Analysis, J.M. Godoy Determination of Nutrients in Aquatic Sediments, H. Agemian Supercritical Fluid Extraction of Organic Contaminants in Sediments, H.-B. Lee and D.R. Gere Each chapter includes a list of references.

Effects of abandoned gold mine tailings on the arsenic concentrations in water and sediments of jack of clubs lake, B.C.

Abstract From 1933 to 1964 gold was extracted by underground mining at the northeast shore of Jack of Clubs Lake. At present, tailings and waste rock 4.5 m thick covers approximately 25 hectares of land adjacent to the lake. Arsenic concentrations (>2,000 μg.g‐1) were found in the tailing materials. Two simultaneous processes are controlling the elevated As concentrations in the lake sediments (up to 1,104 μg.g‐1), deposition of suspended particles enriched with As and subsequent diagenetic cycling of sedimentary As. Arsenic concentrations (as high as 556 μg.L‐1) in water samples adjacent to the tailings indicate mobilization of As. However, dissolved As is readily scavenged or coprecipitated with iron hydroxides. The greatest proportion of As in the sediment cores is associated with iron oxides and sulphides. Under oxic conditions the high concentrations of Fe in the tailings is actually beneficial and very effective at limiting the migration of undesirable elements.

The effect of particle size, chemistry and mineralogy of river sediments on phosphate adsorption

Abstract Sediment samples were collected from two Lake Erie tributaries and separated into ten particle size fractions. The concentrations of major elements, organic and inorganic carbon, mineralogical composition and the capacity for adsorption/ desorption of inorganic P were determined for each particle size fraction. The results indicated that the chemical composition and mineralogy were parameters controlling adsorption of phosphates on sediment particles.

Summary of Surface and Background Concentrations of Selected Elements in the Great Lakes Sediments

Abstract A literature survey was carried out to obtain recent and background concentrations of selected elements (As, Cd, Cu, Cr, Fe, Ni, Pb, Zn, and Hg) in the sediments from different areas of the Great Lakes. This information was required for the revision of the guidelines for the disposal of dredged material at the Canadian side of the Great Lakes. Surveyed literature included articles published during the past 15 years in different scientific journals and governmental and U.S. and Canadian universities reports. Large differences in concentrations of selected elements reported in the Great Lakes sediments reflected different sampling localities and techniques, and methods used for sediment analyses. Concentration ranges reported for surveyed elements were wider for the surface sediments of the depositional basins than those for the pre-colonial sediments. The results of the literature search indicated the need for development of a standard sediment sampling protocol and standard analytical procedures for the assessment of contamination of the sediments at different areas of the Great Lakes.

Trace elements in water, sediments, porewater, and biota polluted by tailings from an abandoned gold mine in British Columbia, Canada

Abstract The concentrations of major and trace elements in different environmental compartments (e.g., water, suspended and bottom sediments, sediment porewater, and biota) of Jack of Clubs Lake (JCL), Wells, British Columbia (Canada), were determined to assess the biogeochemical effects of abandoned gold mine tailings on the aquatic ecosystem of JCL in the Fraser River drainage basin. Arsenic and Pb were transported from the tailings to the lake, where they accumulated in bottom sediments in concentrations up to 1104 and 281 μ/g, respectively. Although the benthic community in the lake was only partially affected, there was evidence that the tailings inhibited a variety of microbial activities in the lake sediments. The concentrations of As, Cd, Cu and Pb in invertebrates collected from streams flowing through mine tailings, and from vegetation growing on the tailings, suggest a potential for contamination of the food chain of the surrounding ecosystems.

Nepheloid Layer in Lake Ontario

A study was designed to investigate the existence and extent of a nepheloid layer in Lake Ontario. A transmissometer profile of the entire water column was obtained monthly from 94 stations in Lake Ontario during the period of August to December, 1981. The profiles indicated that a turbid layer at the lake bottom existed over the entire lake at water depths greater than 60 meters. The thickness of the layer averaged 22 meters in August and September, but doubled to 45 meters in October. In addition, the average transmission was lowered from 60 percent in August and September to 45 percent in October. A significant increase in soluble reactive phosphorus (SRP) and reactive silica (RSiO2) in the nepheloid layer was observed. Quartz and calcite were the major mineral constituents of the suspended matter present in the layer. The particles in the nepheloid layer in the western basin of Lake Ontario consisted of many diatoms and some calcite particles and clay minerals. In the central and eastern basins the number of calcite particles significantly increased. Concentrations of Pb and Zn in the suspended matter sampled from the nepheloid layer at the Niagara River mouth were similar to those found in the 1-cm surface sediment at the same station (124 μg g−1 Pb, 318 μg g−1 Zn,and139 μg g−1 Pb and 356 μg g−l Zn, respectively).

Geochemistry of the Detroit River Sediments

The objectives of the investigation were to provide information on the concentration and distribution of metals in bottom sediments of the Detroit River and to study the association of metals with various sediment components. Concentrations of major elements (Si, Al, Ca, Mg, Na, K, Fe, Mn, and P) and metals (Co, Cr, Cu, Ni, Pb, and Zn), particle size distribution, and mineralogical composition were determined in 20 surficial sediment samples collected along the Detroit River in 1983. Significantly higher concentrations of metals in the Detroit River sediments than those reported in Lake St. Clair and Lake Erie sediments indicated input from sources in the rivers drainage basin. Poor relationships exist between the metals and organic C and the metals and the silt-clay size fraction ( 63 μm. Zn, Ni, Cr, and Pb were accumulated in the 63 μm fraction. Dolomite, feldspars, and quartz were in the 13 to 63 μm fraction and the clay minerals illite, chlorite, and kaolinite were in the < 13 μm fraction. Concentrations and relationships among major elements reflected the mineralogical composition of different particle size fractions.

Effects of mine effluent on uptake of Co, Ni, Cu, As, Zn, Cd, Cr and Pb by aquatic macrophytes

Concentrations of Ni, Co, Cu, Pb, Zn, Cd, Cr and As were determined in aquatic sediments, water and macrophytes collected from a fluvial system, contaminated by mine effluents. Myriophyllum verticillatum collected in May below the trace element point source accumulated 169 µg/g of Ni, 860 µg/g of Co, 37 µg/g of Cu, 31 µg/g of Pb, 92 µg/g of Zn, 6.9 µg/g of Cr and 1,200 µg/g of As (concentrations in dry weight). The aquatic macrophytes Nymphaea odoratae and Pontederia cordata accumulated the investigated trace elements to a much lesser extent. The concentrations of trace elements in Myriophyllum verticillatum decreased from May to August. Correlations were found between the concentrations of total Ni, Co and Cu in the bottom sediment and in the submerged macrophytes. However, there was no correlation between the amounts of these trace elements extractable by 0.5 N HCl from the sediments and the concentrations in the macrophytes.

Transport of arsenic and mercury from gold mining activities through an aquatic system

Abstract Past gold mining pracerties in the Waverley area of Nova Scotiaa, Canada, have left wastes containing arsenic and mercury which are affecting water and sediment in the Shubenacadie River headwater lakes. The concentrations of arsenic and mercury in sediments decreased gradually from 1500 μg g −1 near the Waverley mine site to 120 μg g −1 and 0.5 μg g −1 , respectively, in a downstream lake. The concentrations of arsenic and mercury were determined in water from the lakes and connecting streams and in suspended solids collected from the connecting streams in the spring, summer and fall of 1983 to investigate means of transport within the headwater lakes. The greatest quantity of arsenic (7.1 kg) was transported by suspended solids in November, while most of the mercury was transported by suspended solids during spring and fall, although the concentration of mercury in all water samples was below the detection limit of 0.0005 mg 1 −1 . A significant increase of dissolved iron and manganese concentration was found during summer anoxic conditions in lake bottom waters and in the water of connecting streams. Calculations show that arsenic is most likely associated with iron oxides precipitated after the mixing of iron-rich hypolimnetic water with oxygenated surface lake water, and is transported further downstream by suspended solids.

Geochemical Composition of the Nepheloid Layer in Lake Ontario

Abstract The origin, characteristics, and geochemical composition of suspended matter in the nepheloid layer was investigated in the western, central, and eastern basins of Lake Ontario to evaluate the role of the nepheloid layer in transport of contaminants across the lake. Suspended matter was collected from the nepheloid layer by means of continuous flow centrifuges at eleven stations in the lake in August 1987, 1988, and 1989. The nepheloid layer formation in Lake Ontario commenced in July and its thickness increased gradually up to about 40 m in September. Silica, calcite, and organic matter were the major components of the suspended matter in the nepheloid layer, particularly in the central and eastern basins. The concentrations of Pb, Zn, and Cu in the suspended matter in the nepheloid (up to 683, 1,180, and 396 μg/g, respectively) were greater than those in the bottom sediments (up to 203, 665, and 298, respectively). The concentrations of As, Co, Ni, Cr, V, and Hg were similar or lower than those in the sediments. The concentrations of PCBs in the suspended matter in the nepheloid layer ranged from 151 to 728 ng/g, and were greater than those in most of the sediments. Further, the suspended matter in the nepheloid layer contained more lower chlorinated biphenyls, particularly tetra- and pentachlorobiphenyls, than the sediments. The results of the study indicated that the suspended matter in the nepheloid layer is an important medium in accumulation, recycling, and transport of contaminants in Lake Ontario.