Kent S. Murray

Yeast metallothionein in transgenic tobacco promotes copper uptake from contaminated soils

Metallothioneins (MTs) are metal‐binding proteins that confer heavy metal tolerance and accumulation in yeast. To augment higher plant metal sequestration, the yeast metallothionein (CUP 1) was introduced into tobacco plants. The CUP 1 gene expression and copper and cadmium phytoextraction were determined. To confirm transformation, selfed and kanamycin‐resistant third generation plants were subjected to DNA blot and polymerase chain reaction (PCR) analysis. A 4 mM CuSO4 stress for 7 days resulted in a decline in CUP 1 transcripts versus nonstress conditions. Despite low mRNA levels, CUP 1 transformants accumulated up to seven times more copper in older versus younger leaves during copper stress. Pooled leaves of transgenic plants grown in soils from copper stamp‐sands contained two to three times the copper content as that of the control plants. Unlike some previous reports featuring MT overexpression in plants, CUP 1 seedlings did not significantly sequester or demonstrate tolerance to CdCl2. Using this transgenic approach, yeast CUP 1 expression under nonstressed conditions contributed to copper metal phytoextraction during a subsequent copper challenge. This strategy could be incorporated into plants designed for enhanced phytoremediation of metal contaminants.

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.

Assessment and Use of Indicator Bacteria to Determine Sources of Pollution to an Urban River

Abstract Elevated levels of indicator bacteria within a river system represent a significant impairment to surface water quality in many urban areas within the Great Lakes watershed. Outfalls from combined sewer systems are assumed to be the major source of bacteria to streams in many of these urban areas, including the Rouge River of southeastern Michigan. Current remediation strategies largely disregard other potential sources, including water entering the river from its headwaters region, rural runoff, and contaminated groundwater. These other potential sources of bacterial pollution to the Rouge River were assessed and compared with bacteria contributed from combined sewer outfalls (CSOs). Fecal coliform (FC) and fecal streptococci (FS) densities were determined at 28 locations in the Rouge River Watershed during the spring and summer of 1997, 1998, and 1999. The mean levels of both indicator groups vary considerably along each branch of the river and show no correlation to CSO locations. The magnitude of both FC and FS levels are, in fact, frequently greater at sites upstream of the part of the river influenced by discharges from CSOs. The highest FC levels coincided with rainfall events, but FC levels at various sites along each branch of the Rouge River violated acceptable water quality standards (200 colonies/100 mL) at nearly 50% of the sites even during dry weather. Total suspended solids were moderately correlated with FC (rxa0=xa00.79) throughout the watershed, suggesting that solids may play a role in transporting bacteria into the Rouge River. The data depict a strong influence of upstream water and rural runoff on the water quality of the Rouge River. FC to FS ratios (FC/FS) suggest the primary source of bacteria throughout the watershed is from domesticated animals and wildlife and not from sewage derived from CSOs.

Groundwater Vulnerability, Brownfield Redevelopment and Land Use Planning

An understanding of groundwater vulnerability in urban watersheds is important for the prevention of both surface water and groundwater contamination and can therefore be a useful tool in brownfield redevelopment and land use planning. Although industrial activity in southeastern Michigan has historically been restricted to the urbanized sections of metropolitan Detroit, new industrial development is rapidly taking place in rural and undeveloped areas. Although environmentalists and urban planners agree that industrial site recycling in urban centres (a.k.a. brownfield redevelopment) is preferable to developing green areas, many older sites remain undeveloped due to real and perceived risks. Using a PC-based geographic information system, a conceptual model of solute transport in soil was developed to evaluate potential impacts to both groundwater and surface water quality resulting from industrial development. The model was used to create a map of groundwater vulnerability within the Rouge River watershed of southeastern Michigan. The map has been used to pin-point several rural and undeveloped areas where groundwater quality is threatened by proposed development. It has also clearly demonstrated that many older brownfield sites, within the City of Detroit, are located on materials that have a much lower vulnerability to groundwater contamination and may therefore be far less costly to redevelop than greenfield sites in undeveloped areas of the watershed.

Urban watersheds : geology, contamination, and sustainable development

The Watershed Approach Historical Transformation of Urbanized Watersheds by Industrial Development The Evolution of Industry and the Rouge Watershed Major Themes of the Watershed Approach Used in This Book Organization of This Book PART I: GEOLOGY Geology of Urban Watersheds Geological Processes Affecting Urban Watersheds Sedimentary Processes: From Removal to Rock Formation Identification and Classification of Sedimentary Deposits Sedimentary Depositional Environments Disturbance Water and the Hydrogeology of Watersheds Water Basics Surface Water in Watersheds Groundwater in Watersheds Fundamental Concepts of Groundwater Surface Water-Groundwater Interaction Anthropogenic Influences on Surface Water and Groundwater Conducting Subsurface Environmental Investigations in Urban Watersheds Types and Description of Subsurface Environmental Investigations, Studies, Plans, or Reports Common Environmental Sampling Methods Urban Geologic Mapping Geologic Mapping in an Urban Environment Geologic Vulnerability Subsurface Vulnerability and Vulnerability Map Development Methods Map-Building Example Demonstrating the Significance of Vulnerability Mapping PART II: CONTAMINATION Common Contaminants in Urban Watersheds Contaminant Toxicity Volatile Organic Compounds Polynuclear Aromatic Hydrocarbons Polychlorinated Biphenyls Semivolatile Organic Compounds Heavy Metals Other Contaminants Contaminant Fate and Transport Contaminant Releases into the Environment Principles of Contaminant Fate and Transport Fate and Transport of Contaminants Metal Contamination in Urban Watersheds Heavy Metals in Soil Case Study: Metals in Soil, Rouge River Watershed Case Study: Dissolved Metals in Shallow Groundwater, Rouge River Watershed Contaminant Risk Factors Surface Risk Factor Groundwater Contaminant Risk Factor Soil Contaminant Risk Factor Air Contaminant Risk Factor Discussion and Implications Remediation: Techniques and Cost Remediation Overview Common Soil Remediation Technologies Summary of Soil Remediation Technologies Common Groundwater Remediation Technologies Summary of Groundwater Remediation Technologies Sediment Remediation Surface Water Remediation Air Remediation Cost of Remediation PART III: SUSTAINABLE DEVELOPMENT Urbanization and the Disruption of Matter and Energy Flows within Watersheds Watershed Structure Watershed Function Urbanization and Watersheds: Disruption of Matter and Energy Flows Pollution Prevention Pollution Prevention in the United States Implementing Pollution Prevention Techniques: Industrial Point Sources Implementing Pollution Prevention Techniques for Nonpoint Sources in Urbanized Watersheds Case Studies: Successful and Unsuccessful Redevelopment of Contaminated Sites Case Study 1: Michigan Case Study 2: Illinois Case Study 3: Indiana Case Study 4: Wisconsin Case Study 5: California Case Study 6: New Jersey Science-Based Landscape Planning in Urban Watersheds The Science: Policy Gap Science-Based Landscape Planning Watershed Management Attaining Sustainable Urban Watersheds Sustainability and Sustainable Development A Framework for Beginning Urban Watershed Management Linking the First Step to the Big Picture Glossary of Terms Index

The use of soil Hg to delineate zones of upwelling in low-to-moderate temperature geothermal systems

A soil mercury survey was conducted near the town of Calistoga, California to identify and delineate a buried fault system that is thought to control the upwelling of low-to-moderate temperature geothermal fluids in the upper Napa Valley. Soil samples were collected at 100 m intervals along traverses that crossed hot springs and existing geothermal well sites. Strong mercury anomalies occur along a broadly-defined zone and in close proximity to surface thermal activity including active hot springs and silica sinter formations. In contrast, background mercury concentrations are present in locations with little or no indication of subsurface thermal activity, such as along the margins of the valley or near groundwater wells producing non-thermal water. Analysis of smoothed Hg values reveals a N65W-trending lineament of high Hg concentrations. These results suggest that soil mercury surveys can be a useful and cost-effective method for the identification and mapping of structures controlling subsurface fluid flow in low-to-moderate temperature geothermal systems.

Grain-Size Heterogeneity and Subsurface Stratification in Air Sparging of Dissolved-Phase Contamination: Laboratory Experiments–Field Implications

Air sparging (AS) laboratory experiments were performed to assess the effects of grain-size heterogeneity and sediment stratification on air-flow geometry and area of impact. Results were interpreted in terms of the three air-flow geometries described in the literature: chamber flow, channelized flow, and pervasive/bubbly flow. Compared to sparging experiments in monostratigraphic layers, AS of coarsening-upward sequences can increase the extent of the sediment column affected by air because of changes in air-flow geometry and/or sparge angle at strata transition boundaries. AS of fining-upward sequences can also increase the extent of sediment affected in an overlying unit in which channelized flow occurs by generating multiple air-source points. Laboratory simulations of the AS injection interval, representative grain size, and stratified saturated zone of a field site were also performed. These experiments indicated the potential occurrence of chamber flow at the site and revealed the effect of pulsed AS. The effect is to fill in areas of the sedimentary column between air-flow chambers that otherwise would not be affected by air during continuous sparging. This phenomenon, observed in the laboratory, is a likely explanation for remediation performance at the site.

Improving Environmental Risk Management through Historical Impact Assessments

Abstract A historical contaminant impact assessment was conducted at 48 heavy manufacturing facilities located in 20 different states for a U.S.-based company. The facilities evaluated were industrial manufacturing sites that operated for as long as 100 yr and used several types of hazardous substances, including solvents and degreasers, oils and other petroleum products, paints and pigments, and heavy metals. The purpose of conducting the impact assessment was to provide direction and guidance on future environmental objectives and pollution prevention initiatives. The impact assessment involved examining historical investigative and remediation costs since 1985, types of contaminants, sub-surface geology, hydrology, and regulatory requirements. The results reveled that 85% of the historical environmental costs were associated with hexavalent chromium and chlorinated solvents. Other contaminants, such as oils and other petroleum products and other heavy metals, were far more commonly detected but only accounted for the remaining 15% of costs. The results also indicated that the costs are also strongly associated with the type of geologic environment to which the chemicals were released. As a result of these findings, an aggressive pollution prevention program has been initiated to eliminate the use of those contaminants that are especially expensive to remediate and to develop stronger and more effective engineering controls at facilities located in sensitive ecological areas.

Broadening Diversity in the Geosciences Through Teacher-Student Workshops That Emphasize Community-Based Research Projects

ABSTRACT The Geosciences Institute for Research and Education at the University of Michigan–Dearborn has been an example of a successful and effective model in increasing the participation of underrepresented groups in the geosciences. The program emphasizes involving middle school and at-risk high school students from the Detroit area public schools, along with their teachers in geoscience research projects, through a series of spring and summer workshops. The workshops introduce students to the geosciences by emphasizing how geology can be used as a tool to solve community-based environmental problems. Students work alongside their teachers and university faculty on projects ranging from an assessment of brownfield sites in southwestern Detroit to the installation of groundwater monitoring wells to the evaluation of how former land use is impacting groundwater and surface water quality. Spring workshops focused on students from three African-centered middle schools in Detroit, while the summer workshops focused more on middle school and high school teacher training, but included a small group of middle school and high school students. Instruments used to evaluate the effectiveness of the workshops included the Science Teaching Efficacy Belief Instrument, the Geoscience Concept Inventory, and survey questions from the Watershed Task. Pre- and postworkshop questionnaires and separate teacher–student focus groups demonstrate that we have not only increased student awareness of the geosciences, but we have also motivated students to pursue career opportunities in science. For example, more than half of the students completing the workshop (boys and girls alike) have expressed a strong interest in pursuing a career in the geosciences. Since its inception in 2005, we have reached over 100 middle and high school students, and 75 teachers. During this same period, the Earth Science major at the University of Michigan–Dearborn has tripled in size, and we have quadrupled the number of minority students taking introductory geology courses.

Computer-Assisted Mineral Identification for Introductory Geology Courses

Mineral Database is an interactive computer program that allows students to quickly identify minerals by their physical properties. The program incorporates color images and a physical-properties database, called Mineral KnowledgeBase, which includes individual histories and backgrounds of the common rock-forming minerals. The program was written by one of the authors (Yavine) in Visual BASIC and runs under Microsoft Windows. The package currently includes over 150 of the most common minerals although additional minerals, or mineral categories, such as oxides, sulfides, phosphates, and so forth could easily be added to customize the program for use in upper-level courses. A search/match module allows students to use the program to identify minerals if physical properties are known or conversely to look up physical properties of a particular mineral. Use of the program in an introductory physical-geology class to aid in the identification of minerals was enthusiastically received by students when used in c...