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October, 2006
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Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

1Bioprocesses Department, Laboratory of Environmental Biotechnology, Unidad Profesional Interdisciplinaria de Biotecnología, Instituto Politécnico Nacional, 2Laboratory of Molecular Biology, Escuela Superior de Medicina, Instituto Politécnico Nacional

JoVE 52956


Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

1Department of Offshore, Process and Energy Engineering, Cranfield University, 2School of Applied Chemical and Environmental Sciences, Sheridan College Institute of Technology and Advanced Learning, 3School of Engineering, University of Guelph, 4Carbon Systems Engineering, Centre for Combustion, Carbon Capture and Storage, Cranfield University

JoVE 55062


Nutrients in Aquatic Ecosystems

JoVE 10023

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Nitrogen and phosphorus are essential plant nutrients found in aquatic ecosystems and both are monitored as a part of water quality testing because in excess amounts they can cause significant water quality problems. 

Nitrogen in water is measured as the common form nitrate (NO3-) that is dissolved in water and readily absorbed by photosynthesizers such as algae. The common form of phosphorus measured is phosphate (PO43-), which is strongly attracted to sediment particles as well as dissolved in water. In excess amounts, both nutrients can cause an increase in aquatic plant growth (algal bloom, Figure 1) that can disrupt the light, temperature, and oxygen levels in the water below and lead to eutrophication and hypoxia (low dissolved oxygen in water) forming a “dead zone” of no biological activity. Sources of nitrates and phosphorus include wastewater treatment plants, runoff from fertilized lawns and agricultural lands, faulty septic systems, animal manure runoff, and industrial waste discharge. Figu

 Environmental Science

Dissolved Oxygen in Surface Water

JoVE 10016

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Dissolved oxygen (DO) measurements calculate the amount of gaseous oxygen dissolved in surface water, which is important to all oxygen-breathing life in river ecosystems, including fish species preferred for human consumption (e.g. bluegill and bass), as well as decomposer species critical to the recycling of biogeochemical materials in the system. The oxygen dissolved in lakes, rivers, and oceans is crucial for the organisms and creatures living in it. As the amount of dissolved oxygen drops below normal levels in water bodies, the water quality is harmed and creatures begin to die. In a process called eutrophication, a body of water can become hypoxic and will no longer be able to support living organisms, essentially becoming a “dead zone.” Eutrophication occurs when excess nutrients cause algae populations to grow rapidly in an algal bloom. The algal bloom forms dense mats at the surface of the water blocking out two essential inputs of oxygen for water: gas exchange from the atmosphere and photosynthesis in the water due to the lack of light below the mats. As dissolved oxygen levels decline below the surface, oxygen-breathing organisms die-off in large amounts, creati

 Environmental Science

Quantifying Environmental Microorganisms and Viruses Using qPCR

JoVE 10186

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Bradley Schmitz

Quantitative polymerase chain reaction (qPCR), also known as real-time PCR, is a widely-used molecular technique for enumerating microorganisms in the environment. Prior to this approach, quantifying microorganisms was limited largely to classical culture-based techniques. However, the culturing of microbes from environmental samples can be particularly challenging, and it is generally held that as few as 1 to 10% of the microorganisms present within environmental samples are detectable using these techniques. The advent of qPCR in environmental microbiology research has therefore advanced the field greatly by allowing for more accurate determination of concentrations of microorganisms such as disease-causing pathogens in environmental samples. However, an important limitation of qPCR as an applied microbiological technique is that living, viable populations cannot be differentiated from inactive or non-living populations. This video demonstrates the use of qPCR to detect pepper mild mottle virus from an environmental water sample.

 Environmental Microbiology

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

1Division of Physical Therapy, Department of Orthopedics & Rehabilitation, University of New Mexico, 2Department of Ecosystem Science and Management, University of Wyoming, 3School of Pharmacy, University of Wyoming, 4Department of Environmental and Radiological Health Sciences, Colorado State University, 5Center for Environmental Medicine, Colorado State University, 6College of Pharmacy, California Northstate University

JoVE 52715


Water Quality Analysis via Indicator Organisms

JoVE 10025

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Luisa Ikner

Water quality analysis monitors anthropogenic influences such as pollutants, nutrients, pathogens, and any other constituent that can impact the water’s integrity as a resource. Fecal contamination contributes microbial pathogens that threaten plant, animal, and human health with disease or illness. Increasing water demands and strict quality standards require that water being supplied for human or environmental resources be monitored for low pathogen levels. However, monitoring each pathogen associated with fecal pollution is not feasible, as laboratory techniques involve extensive labor, time, and costs. Therefore, detection for indicator organisms provides a simple, rapid, and cost effective technique to monitor pathogens associated with unsanitary conditions.

 Environmental Microbiology

Detection of Bacteriophages in Environmental Samples

JoVE 10190

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Alex Wassimi

Viruses are a unique group of biological entities that infect both eukaryotic and prokaryotic organisms. They are obligate parasites that have no metabolic capacity, and in order to replicate, rely on host metabolism to produce viral parts that self-assemble inside host cells. Viruses are ultramicroscopic—too small to be viewed with the light microscope, visible only with the greater resolution of the electron microscope. A viral particle consists of a nucleic acid genome, either DNA or RNA, surrounded by a protein coat, known as a capsid, composed of protein subunits or capsomers. In some more complex viruses, the capsid is surrounded by an additional lipid envelope, and some have spike-like surface appendages or tails. Viruses that infect the intestinal tract of humans and animals are known as enteric viruses. They are excreted in feces and can be isolated from domestic wastewater. Viruses which infect bacteria are known as bacteriophages, and those which infect coliform bacteria are called coliphages (Figure 1). The phages of coliform bacteria are found anywhere coliform bacteria are found.

 Environmental Microbiology

The Portable Chemical Sterilizer (PCS), D-FENS, and D-FEND ALL: Novel Chlorine Dioxide Decontamination Technologies for the Military

1United States Army-Natick Soldier RD&E Center, Warfighter Directorate, 2Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 3Lawrence Livermore National Laboratory, 4Children's Hospital Oakland Research Institute

JoVE 4354


A Hybrid DNA Extraction Method for the Qualitative and Quantitative Assessment of Bacterial Communities from Poultry Production Samples

1Egg Safety and Quality Research Unit, USDA-Agricultural Research Service, 2Poultry Microbiological Safety and Processing Research Unit, USDA-Agricultural Research Service, 3Department of Biochemistry and Biophysics, Oregon State University, 4College of Public Health, University of Georgia, 5Department of Biological Sciences, Center for Microbial Genetics and Genomics, Northern Arizona University

JoVE 52161


Total Internal Reflection Absorption Spectroscopy (TIRAS) for the Detection of Solvated Electrons at a Plasma-Liquid Interface

1Department of Chemical and Biomolecular Engineering, University of Notre Dame, 2Department of Aerospace and Mechanical Engineering, University of Notre Dame, 3Department of Chemistry and Biochemistry, Notre Dame Radiation Laboratory, University of Notre Dame

Video Coming Soon

JoVE 56833

 JoVE In-Press

Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples

1Department of Pathology and Laboratory Medicine, Faculty of Medicine, The University of British Columbia, 2Coastal Genomics, 3British Columbia Public Health Microbiology and Reference Laboratory

JoVE 52685


Developing a Salivary Antibody Multiplex Immunoassay to Measure Human Exposure to Environmental Pathogens

1National Exposure Research Laboratory, U.S. Environmental Protection Agency, 2National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 3Oak Ridge Institute for Science and Education, 4Department of Biological Sciences, McMicken College of Arts and Sciences, University of Cincinnati

JoVE 54415

 Immunology and Infection

Proton Exchange Membrane Fuel Cells

JoVE 10022

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

The United States consumes a large amount of energy – the current rate is around 97.5 quadrillion BTUs annually. The vast majority (90%) of this energy comes from non-renewable fuel sources. This energy is used for electricity (39%), transportation (28%), industry (22%), and residential/commercial use (11%). As the world has a limited supply of these non-renewable sources, the United States (among others) is expanding the use of renewable energy sources to meet future energy needs. One of these sources is hydrogen. Hydrogen is considered a potential renewable fuel source, because it meets many important criteria: it’s available domestically, it has few harmful pollutants, it’s energy efficient, and it’s easy to harness. While hydrogen is the most abundant element in the universe, it is only found in compound form on Earth. For example, it is combined with oxygen in water as H2O. To be useful as a fuel, it needs to be in the form of H2 gas. Therefore, if hydrogen is to be used as a fuel for cars or other electronics, H2 needs to be made first. Thusly, hydrogen is often called an “energy carrier” rather than a “fuel.”

Safety Precautions and Operating Procedures in an (A)BSL-4 Laboratory: 1. Biosafety Level 4 Suit Laboratory Suite Entry and Exit Procedures

1Integrated Research Facility at Frederick, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 2Environmental Health and Safety, Biological and Chemical Safety Program, University of Texas Medical Branch

JoVE 52317

 Immunology and Infection

Introduction to Titration

JoVE 5699

Source: Laboratory of Dr. Yee Nee Tan — Agency for Science, Technology, and Research

Titration is a common technique used to quantitatively determine the unknown concentration of an identified analyte.1-4 It is also called volumetric analysis, as the measurement of volumes is critical in titration. There are many types of titrations based on the types of reactions they exploit. The most common types are acid-base titrations and redox titrations.5-11 In a typical titration process, a standard solution of titrant in a burette is gradually applied to react with an analyte with an unknown concentration in an Erlenmeyer flask. For acid-base titration, a pH indicator is usually added in the analyte solution to indicate the endpoint of titration.12 Instead of adding pH indicators, pH can also be monitored using a pH meter during a titration process and the endpoint is determined graphically from a pH titration curve. The volume of titrant recorded at the endpoint can be used to calculate the concentration of the analyte based on the reaction stoichiometry. For the acid-base titration presented in this video, the titrant is a standardized sodium hydroxide solution and the analyte is domestic vinegar. Vinegar is an acidic liquid that

 General Chemistry

Turbidity and Total Solids in Surface Water

JoVE 10015

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Turbidity and total solids are related measurements addressing clarity of surface waters. Turbidity is an indirect measure of water clarity that determines the amount of light that can pass through the water. Total solids is a direct measurement of solid particles suspended in water determined by weight. High levels of turbidity and total solids are caused by soil erosion, waste discharge, runoff, or changes in ecological communities including algal growth or abundance of benthic organisms that can disrupt sediments up into the water. Higher levels of turbidity and suspended solids can lower water quality by absorbing heat causing an increase in water temperature and a decrease in oxygen levels (warm water holds less oxygen). These conditions can also cause a decrease in photosynthesis as less sunlight penetrates the water, making the water unable to support some aquatic life. Suspended solids can also clog gills, smother eggs, reduce growth rates, and disrupt microhabitats of many aquatic organisms. One method of measuring turbidity includes using a Secchi disk. A Secchi disk is a metal disk with alternate black and white quarters (Figure 1). It is attached to a rope that

 Environmental Science

Using a pH Meter

JoVE 5500

Source: Laboratory of Dr. Zhongqi He - United States Department of Agriculture

Acids and bases are substances capable of donating protons (H+) and hydroxide ions (OH-), respectively. They are two extremes that describe chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic nor basic is neutral. The values of proton concentration ([H+]) for most solutions are inconveniently small and difficult to compare so that a more practical quantity, pH, has been introduced. pH was originally defined as the decimal logarithm of the reciprocal of the molar concentration of protons , but was updated to the decimal logarithm of the reciprocal of the hydrogen ion activity . The former definition is now occasionally expressed as p[H]. The difference between p[H] and pH is quite small. It has been stated that pH = p[H] + 0.04. It is common practice to use the term 'pH' for both types of measurements. The pH scale typically ranges from 0 to 14. For a 1 M solution of a strong acid, pH=0 and for a 1 M solution of a strong base, pH=14. Thus, measured pH values will lie mostly in the rang

 General Chemistry

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