Areas Of Enrichment Research Articles

Statistical comparisons of heavy-metal concentrations in river sediments

Statisticalt tests were used to determine lead, copper, and chromium enrichment in sediments from the Lower Branch of the Rouge River in southeast Michigan, USA. Both absolute metal concentrations and ratios of trace metal to conservative metal concentrations were used to compare sampled sites along the Lower Branch of the Rouge River to background sites in the headwaters region. Concentration ratios were used to reduce the effects of certain chemical and physical characteristics on the level of metal contained in a given sediment. Results from the comparison of sample sites to the background reveal metal enrichment at several sites, particularly along the highly urbanized, downstream section of the river. This section of the Lower Branch of the Rouge River exhibits significant lead and copper contamination, as well as measurable chromium enrichment when using either concentrations alone or ratios as methods of comparison. The areas of metal enrichment appear to coincide closely with areas of known anthropogenic activities. Of particular interest, however, is the enrichment of lead and copper at two upstream sites where the statistical tests suggest an anthropogenic source for the enrichment, but where no previously known cultural activities existed. These data prompted a historical search of records, which discovered several abandoned landfills immediately upstream of the metal enrichment sites.

Statistical comparisons of heavy-metal concentrations in river sediments

Statisticalt tests were used to determine lead, copper, and chromium enrichment in sediments from the Lower Branch of the Rouge River in southeast Michigan, USA. Both absolute metal concentrations and ratios of trace metal to conservative metal concentrations were used to compare sampled sites along the Lower Branch of the Rouge River to background sites in the headwaters region. Concentration ratios were used to reduce the effects of certain chemical and physical characteristics on the level of metal contained in a given sediment. Results from the comparison of sample sites to the background reveal metal enrichment at several sites, particularly along the highly urbanized, downstream section of the river. This section of the Lower Branch of the Rouge River exhibits significant lead and copper contamination, as well as measurable chromium enrichment when using either concentrations alone or ratios as methods of comparison. The areas of metal enrichment appear to coincide closely with areas of known anthropogenic activities. Of particular interest, however, is the enrichment of lead and copper at two upstream sites where the statistical tests suggest an anthropogenic source for the enrichment, but where no previously known cultural activities existed. These data prompted a historical search of records, which discovered several abandoned landfills immediately upstream of the metal enrichment sites.

Heavy metals and arsenic in sediments from the continental shelf of the Northern Tyrrhenian/Eastern Ligurian Seas

Arsenic, chromium, cobalt, copper, lead, nickel, vanadium and zinc distributions in surficial and core sediments of the marine basin between La Spezia and Livorno (Northern Tyrrhenian/Eastern Ligurian Seas, west-central Italy) have been investigated. Comparison of heavy metal distribution with grain size and mineralogical data allowed the identification of vast areas where the sediment fine fraction appears affected by heavy metal anthropogenic contamination. In the fine particulate As, Cr, Pb and Zn show the highest and most widespread enrichments with respect to natural background, while Cu and V have lower and more limited positive anomalies. Co and Ni distributions only exhibit few and small areas of moderate enrichment. For nearly all the analyzed elements the strongest positive anomaly is located off Livorno port, where the presence of the shallow Meloria Shoals induces slow circular water movements, which act as sediment sinks to the heavy-metal-bearing particulate. For some elements (particularly Cr), significant point anomalies also occur at the mouth of some streams, where flocculation phenomena cause near-shore deposition of contaminated silty clays.

A comparison of lithogeochemical and biogeochemical patterns associated with gold mineralization in mountainous terrain of southern British Columbia

Analyses of rock and tree tissue samples collected from an area surrounding gold mineralization at the inactive Carolin mine show geochemical distribution patterns with some striking similarities and significant differences. Lithogeochemical sampling outlines a zone, several hundred meters across, in which hydrothermally altered rocks are enriched in Na and depleted in K and Ba. Within this zone lies a 40 m wide area where the rocks are enriched sporadically in Au and As. The Au, As, and Na biogeochemical halos outlined by twigs and needles of the most common tree in the survey area, Pacific silver fir (Abies amabilis), are significantly larger in areal extent than the respective lithogeochemical halos of these elements. This is a result of physical and chemical downslope dispersion of these elements in the colluvium and ground water. Differences in the biogeochemical and lithogeochemical patterns of Ba and Cr are attributed to the availability of these elements to the plant roots: in the hydrothermally altered rocks, Ba and Cr are more readily released from the crystal structure of such minerals as sericite and fuchsite than in the nonaltered rocks where these elements are most likely contained in K feldspar and chromite. This comparative study indicates that the biogeochemical method is a valuable approach to gold exploration in the mountainous terrain of British Columbia, because trees can integrate and amplify the geochemical signatures of rocks, surficial deposits, and ground water and give rise to large and intense anomalies derived from narrow zones of mineralization. Sampling and analysis of tree tissues is a cost-efficient method to identify areas of metal enrichment. At the Carolin mine, reconnaissance-level sampling at a density of a few trees per square kilometer would have been sufficient to identify the area of anomalously high Au, As, and Na concentrations. Reconnaissance biogeochemical surveys at this sample density in rugged terrain may assist in identifying valleys hosting mineralization that subcrops beneath a veneer of surficial deposits, and thereby, provide a focus for followup prospecting by lithogeochemical or other methods of exploration.

Modeling the spatial variability of natural trace element concentrations in groundwater

A conceptual stochastic model is developed that describes the natural spatial variability of nonreactive solute concentrations in large groundwater systems. The spatial variation in aqueous concentration is associated with dissolution from source areas of high mineral enrichment in the aquifer matrix. The stochastic model considers randomly varying inputs of a solute species from source deposits that occur as a two‐dimensional spatial Poisson process. A steady state advective‐dispersive transport equation is utilized to predict the downgradient movement of the solute from the source areas. The total groundwater concentration at any location is calculated from the superposition of the individual contributions from each source area in the aquifer. A spatially varying concentration field results, described mathematically by a filtered Poisson process model. The theoretical concentration field is nonstationary, with the mean and variance increasing, and the coefficient of variation decreasing, in the direction of groundwater flow. Gaussian fields for abundant elements and highly skewed probability distributions for trace elements are indicated by the filtered Poisson process model. Evaluation of elemental concentration data from the Sherwood aquifer in England demonstrates how field data may be analyzed in the context of the stochastic model.

Distributions of proteins and lipids in the erythrocyte membrane.

Fluorescence digital imaging microscopy was used to characterize erythrocyte membrane domains. To investigate the role of specific proteins in forming lipid domains, erythrocyte ghosts were double-labeled with fluorescent phospholipids and a fluorescent label specific for band 3, the major integral membrane protein. Areas of enrichment, or domains, were observed for both the protein and lipid components. The size and enrichment of the protein and lipid domains in the membrane depended upon the ionic strength but not the temperature. Also, there was a higher correlation between the areas of band 3 and phosphatidylcholine enrichment than between band 3 and phosphatidylserine enrichment. This is consistent with band 3 playing a role in the formation of the phosphatidylcholine domains. Furthermore, areas of spectrin enrichment also were observed in immunofluorescently labeled ghosts, and the band 3 domains were found to coincide with the spectrin domains. Thus, the distribution of band 3 in ghosts is influenced by interactions with the cytoskeleton. Together, these experiments illustrate the type of membrane heterogeneity present in erythrocyte ghosts and the type of lipid and protein interactions that can affect the domains.

Talitrid amphipods (Crustacea) as biomonitors for copper and zinc

Data are presented on the copper and zinc concentrations of four talitrid amphipod species (standard dry weight 10 mg), i.e. Orchestia gammarellus (Pallas), O. mediterranea Costa, Talitrus saltator Montagu and Talorchestia deshayesii (Audouin), from 31 sites in S.W. Scotland, N. Wales and S.W. England. More limited data are also presented for cadmium in O. gammarellus (three sites) and T. deshayesii (one site). In S.W. Scotland, copper concentrations were raised significantly in O. gammarellus from Whithorn and Auchencairn (Solway) and Loch Long and Holy Loch (Clyde). In S.W. England, copper concentrations were highest at Restronguet Creek, Torpoint and Gannel (Cornwall). Samples of O. gammarellus from Islay (inner Hebrides) taken adjacent to the effluent outfalls of local whisky distilleries fell into two groups based on copper concentrations (presumably derived from copper stills), the higher copper levels deriving from the more productive distilleries. High copper levels were found in T. saltator and Tal. deshayesii from Dulas Bay (Wales). Zinc levels in O. gammarellus were high in Holy Loch and Auchencairn (Scotland), Gannel and Torpoint (England) but extremely elevated (as was Zn in O. mediterranea) at Restronguet Creek. Zinc was also high in T. saltator from Dulas Bay (Wales), but not in Tal. deshayesii. Cadmium levels in O. gammarellus from Kilve (Bristol Channel) were much raised. These differences (a) conform with expectations of elevated bioavailability of these metals from well researched areas (S.W. England & N. Wales), and (b) identify hitherto unappreciated areas of enrichment in S.W. Scotland. Orchestia gammarellus is put forward as a suitable biomonitor for copper and zinc in British coastal waters.

How to conduct a diagnostic activity analysis: Five steps to a more effective organization

National Productivity ReviewVolume 7, Issue 2 p. 152-160 Article How to conduct a diagnostic activity analysis: Five steps to a more effective organization Philip Janson, Philip Janson Philip Janson is a consultant at the New York City office of Organization Resources Counselors, Inc., an international management and employee relations consulting firm. He has consulted in the areas of manufacturing, financial services, and health care. Previously, he was a senior consultant at Roy W. Walters and Associates, where he consulted in the areas of job enrichment, productivity improvement, and job satisfaction.Search for more papers by this authorMurray E. Bovarnick, Murray E. Bovarnick Murray E. Bovarnick is vice president of Organization Resources Counselors, Inc., working out of its New York City office. He manages client engagements in the areas of organization design, management practices, compensation management, and employee-relations policies.Search for more papers by this author Philip Janson, Philip Janson Philip Janson is a consultant at the New York City office of Organization Resources Counselors, Inc., an international management and employee relations consulting firm. He has consulted in the areas of manufacturing, financial services, and health care. Previously, he was a senior consultant at Roy W. Walters and Associates, where he consulted in the areas of job enrichment, productivity improvement, and job satisfaction.Search for more papers by this authorMurray E. Bovarnick, Murray E. Bovarnick Murray E. Bovarnick is vice president of Organization Resources Counselors, Inc., working out of its New York City office. He manages client engagements in the areas of organization design, management practices, compensation management, and employee-relations policies.Search for more papers by this author First published: Spring 1988 https://doi.org/10.1002/npr.4040070207 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume7, Issue2Spring 1988Pages 152-160 RelatedInformation

Field effects of platform discharges on benthic macrofauna

Although there were originally no statutory obligations for North Sea oilfield developers to monitor the environmental impact of their activities, many companies undertook such studies voluntarily. The central and northern North Sea is principally a level-bottom habitat and can be broadly considered as being dominated by variations of the classicalAmphiurabenthic community. Early approaches to monitoring studies involved the use of grids of sampling stations extending several kilometres in every direction from the proposed site of the installation. More recently it has been found that the major impact on the environment is from the discharge of oil-based drilling cuttings at the platforms and drilling rigs. Efforts are now concentrated closer to the installations, using transects starting as near to the source of the discharge as possible. By using community parameters such as diversity and equitability, it has been shown that the fauna responds with a dramatic drop in values of these measures close to the platform. However, in most surveys, background values are regained between 500 and 1000 m from the installation. This seems to be the case regardless of whether diesel or low toxicity oil-based drilling fluids are used. Numbers of individuals and biomass responded in a similar way at some installations using ‘low toxicity’ oil-based drilling muds but increased at others using diesel oil-base. The latter response is similar to that of areas of great organic enrichment while the drop in numbers is more indicative of disturbed or toxic conditions. The markedly patchy distribution of drilling cuttings around the production platforms calls into question the sampling strategies that have been adopted for offshore surveys in the past. The extreme variation of figures, particularly oil levels in sediments, makes it almost impossible to establish firm connections between cause and effect. The effects of the discharge of cuttings on the benthic environment has been shown to be very severe, but only in a very localized area around the installations. It is suggested that attention is now focused on the persistence of the oil in the cuttings and that future monitoring strategies should include this in their scope.

Genetic transformation with cell wall-associated deoxyribonucleic acid in Bacillus subtilis.

Cell walls from bacillus subtilis 168 were prepared by conventional methods and found to contain deoxyribonucleic acid (DNA). In transformation assays, after autolysis, it was found that two major regions of the chromosome were selectively enriched in the wall preparations. One region clustered around the replication origin and is represented by the markers purA16, ts8132, thiC5, sacA321, and hisA1. The other region included the replication terminus with representative loci metB10, citK5, gltA292, and pyrA1. All other (internal) loci which were examined showed no statistical enrichment. The two areas of enrichment were similar to but more extensive than those reported for membrane-DNA complexes. The wall preparations also contained protein and lipid, indicating a possible membrane involvement. Analyses of the cell walls revealed that the fatty acid composition of the membrane component was not typical of the for B. subtilis protoplast membranes or for lipoteichoic acids. In addition, radioiodination of cell wall autolysates, followed by gel electrophoresis and autoradiography, demonstrated the presence of proteins not readily detectable in bulk protoplast membranes or on the surfaces of intact cells. These data suggest that a unique component of the membrane and regions of the B. subtilis genome involved in DNA replication events are tightly associated with cell walls. The binding of DNA-membrane complexes to the "rigid" cell wall and the replication of the wall could be a mechanism by which the segregation of growing chromosomes occurs.

Application of the electron microprobe to two particular problems in medical research

In two areas of medical research, the electron microprobe has proved to be a useful tool. The most attractive feature of a scanning electron microprobe quantometer in medicine is the possibility of simultaneous observation and X-ray analysis of domains in their original environment of cells and tissue. In the present study, microprobe analysis was used to identify foreign elements not normally present in the human body. Thorium has been found previously in the liver by chemical methods, but the usefulness of the microprobe was to locate the areas of thorium enrichment within the connective tissue.

Dispersal of Mississippi Sediment in the Gulf of Mexico

ABSTRACT Pleistocene and Recent Mississippi sediments possess a distinctive heavy mineral assemblage which retains its identity between Cairo, Illinois and the Gulf of Mexico Abyssal Plain. Thus this assemblage may be used to trace the Mississippi contribution to the Gulf of Mexico from fluvial, through deltaic, neritic and bathyal, to abyssal environments. Significant changes in the heavy mineral assemblage of sediments in the Gulf are related to source changes and not to the reworking or selective sorting of Mississippi sediments. As a result, three distinct sediment input sources may be recognized for detrital sediments in the Gulf of Mexico Abyssal Plain, 1) The Mississippi, 2) the Rio Grande, and 3) the rivers of north-east Mexico. The Mississippi contribution is dominant and is only repl ced by other inputs in the northwest and southwest corners of the abyssal plain. On the Louisiana-Texas Inner Continental Shelf, Mississippi sediment forms a veneer which extends between the present delta and the Sabine River. Dredge samples reveal that underlying sediments were derived from the central Texas rivers to the west, probably during a period of regression which occurred between 10,000 and 7,000 B.P. The interaction of a high zircon content and intense selective sorting in the Inner Continental Shelf sediments has resulted in two areas of zircon enrichment which may be of economic significance. Because of the insensitivity of the heavy mineral assemblage of the Mississippi contribution to processes of selective sorting and reworking, only 200 non-opaque grains from one size fraction of one sample are needed to characterize this contribution.

Precipitates from hydrothermal exhalations on the East Pacific rise

On the very crest of the East Pacific rise, in equatorial latitudes--particularly 12 degrees to 16 degrees South, the sediments are enriched in Fe, Mn, Cu, Cr, Ni, and Pb. The correlation of these areas of enrichment to areas of high heat flow is marked. It is believed that these precipitates are caused by ascending solutions of deep-seated origin, which are probably related to magmatic processes at depth. The rise is considered to be a zone of exhalation from the mantle of the earth, and these emanations could serve as the original enrichment in certain ore-forming processes. Ba and Sr are enriched on the flanks of the rise.

Review of the oceanographic programs of the Pacific Oceanic Fishery Investigations

The Pacific Oceanic Fishery Investigations (POFI), U.S. Fish and Wildlife Service, has, since early 1950, been engaged in oceanographic surveys of the tropical and subtropical central Pacific, and since last year the northern temperate central Pacific. These studies support POFI's exploratory fishing program, stressing the location of areas of enrichment and increased productivity in the upper layers. The tabulated data from the cruises, together with vertical sections of the measured fields and brief descriptive texts, are published as Special Scientific Reports of the U.S. Fish and Wildlife Service. In the tropical central Pacific, standard oceanographic work is nearing completion, with reports published on seven cruises crossing and defining the equatorial current system (lat. 15°N–10°S, long. 140°W–180°). Similar reports on seven cruises in Hawaiian Islands offshore waters and three cruises to temperate waters north of Hawaii (lat. 25°N–40°N, long. 140°–170°E.) are in preparation. Plans for 1955 include a reconnaissance oceanographic cruise to the equatorial eastern Pacific in cooperation with Scripps Institution of Oceanography and the Peruvian Hydrographic Office, and participation in NORPAC, a joint survey of the entire Pacific north of 25°N. latitude during July, August, and September by POFI, SIO, the State of California, University of Washington, Pacific Oceanic Group of Canada, and Japanese agencies.