• Lab Report Format
• Air Sample Analysis Laboratory (including GC/MS Analysis of VOC's)
• How to take the air sample Using the Supelco Sampler
• Water Sample Analysis Laboratory
• HP 4500 ICP-MS Operation Manual
• Environmental Modeling and Evaluation Project
• The Project Assignment
• Presentation, Paper Organization, and Evaluation Elements Desired
• Grading of Presentation and Paper
• Model Abstracts
• Peer Evaluation Form

   

  Examples of Past Group Presentations - SPRING 2000

• TSCREEN: A Model for Calculating Toxic Air Pollutant Concentrations
• CAMEO: Special Report
• An Evaluation of BIOPLUME III - A Natural Attenuation Decision Support System
• BIOCHLOR - Natural Attenuation Decision Support System
• HSCTM-2D
  

Environmental Chemistry, 552
Laboratory Report

1. Laboratory reports are to be done collaboratively with your cooperative learning groups.

2. Combine both laboratories into a single report with two parts and hand both in together with each part independent of the other.

3. Some guidelines of what is expected in the laboratory reports are provided below. However, do not let this prevent you from including other points that you think are important or being creative in the presentation. The points provided are the minimum requirements to obtain all the points for these laboratories. You may however, include other points and concepts that you feel are important or contribute to your report. Length for the sake of mass is not one of the criteria. Use your collective group conclusions on what is appropriate and reach consensus and agreement as will be done when you are working in research group settings with your colleagues in your respective careers.

4. Summarize all procedures either on the boat, in the laboratory or in your data analysis methodology.

5. (see examples of creative suggestions below)

6. Try to imagine how these skills may be used or your understanding of these skills may be useful to you in your environmental careers.

7. An evaluation will be made of the comprehension of the concepts involved in the analytical process you used.

8. A self and peer evaluation form is required from each member of the group.

9. Enjoy the experience.

1. Introduction and Sampling. Objective: State the objectives of the experiment.
   Sample: Describe the samples in detail
   Sampling: Describe the data quality objectives and your sampling protocol
         DQO
         Protocol
         Methods of sample collection
         Specific descriptions of sampling equipment
         Other descriptions for clarity as necessary
   Describe the sampling for both the air and water sampling in the appropriate sections of the laboratory reports.

2. Instrument and fundamental theory behind its operation. What is the basis for its analytical qualitative and quantitative ability? How does it work? Describe how it functions and draw a diagram of the sample path through the instrument and what it (the sample) is doing and how it changes at each stage of processing.

3. Procedure. Describe the experiment whether on the boat or in the classroom. Describe the solutions prepared, instrument settings, and measurements taken and method for each type of sample or sub-sample. Reference standard procedures rather than repeating them. However, describe the equipment and any pertinent deviations from standard protocol and give rational for these.

4. Results. Present your raw data, calculations, and graphs. Include a copy of chart recordings or printouts obtained from instrumentation. Describe how you have transformed the data into information. Discuss in the discussion section the information you have learned.

5. Data work-up. What conclusions can you draw from the data? Are there other ways or alternatives to the data evaluation methods you have chosen? If so provide a short discussion of why your chose the data evaluation tools that you used. What observations can you make? What statistical evaluations are appropriate in your collective opinions?

6. Discussion. Did you get the expected results? If not, why not? Provide a discussion of what the data means. Include how you could further analyze the samples if more time, effort, money were expended. What was not evaluated due to time and resources and extending the effort? Other pertinent discussions may be appropriate.

7. Conclusion. What main points can you conclude from this experiment?

8. Additional Questions. Provide short agreed upon discussions of the following points.
         What did you learn from the experience?
         What would you do differently if you were doing it again?
         Was the experience valuable?
   

         Optional: Pose thoughtful questions and make suggestions for next year's laboratory.
   

   Note: I am very concerned with the quality of your presentation and with its appropriate documentation of field sampling and laboratory data. These are the overall general guidelines.

Suggestions for creativity in the laboratory:

1. A comparison could be made of the actual Fe concentration and a comparison with the Minteq model projection for that pH and a representative approximation for this type of water.

2. Identification of major air contaminants and the relationship to indoor air quality can be evaluated. Concentration levels and limits for outdoor air can be compared from regulatory sources and conclusion can be drawn.
3. Comparisons between the three different rivers and the relationship of the Ohio to its two tributaries could be a theme that could be of interest to a group.
4. Integration of the data taken on board ship with the analytical data could be done even though this was not specifically asked for. The pH has specific influences on the concentration data of other elements.
5. The sources of specific indoor air components could be hypothesized and follow-up experiments could be devised and suggested to validate these hypotheses.

Sample Preparation:

Sampling Tube Information:
First you must extract the Volatile Hydrocarbons from the activated carbon from the collector tube so that it can be analyzed by the GC/MS.

Sampling Tubes Used:
These are Supelco ORBO - 100 absorbent tubes with 350 and 175 mg activated carbon chambers.

The 175 mg chamber is only for backup and will not be analyzed.
The 350 mg chamber is the primary chamber and was the one first encountered by the VOC contaminants in the air you sampled.

I. Break the glass vial that contains the carbon and remove the carbon to a filter for elution.

Use a file to score the tube at the dividing glass wool plug between the longer and shorter carbon sections (see figure 1.). Consult the laboratory instructor for additional tips on safety and technique. You will be using the larger portion so break the vile in the larger portion not the smaller portion.

Figure 1. Breaking the ORBO - 100 activated carbon tube.

II. Eluting the volatile organic carbon form the activated carbon with a solvent (hexane).

Pour the activated carbon from the tube into a small filter paper mounted in the funnel of the suction apparatus that has been assembled similar to Figure 2. Elute off the volatile organic carbon (VOC) sample with about 2-ml of hexane.

Use a pipette to add hexane to the sample. Add 1 ml of hexane at a time to elute the sample into the GC/MS vile.

Remove the GC/MS auto-sampler vile from the vacuum apparatus.

Screw on the auto-sampler vile and septum.

Take the sample to the GC/MS

Figure 2. Filter assembly for removing the VOCs from the activated carbon with solvent.

III. GC/MS Analysis

GC/MS Varian Saturn II is equipped with a 3410 Gas Chromatograph.

GC/MS Analysis of VOC's from Indoor Air Samples

Spring 2000

Prepared by Sejal (Shah) Iyer

GC/MS is a synergistic combination of two powerful analytic techniques, viz., Gas Chromatography, which separates the components of a mixture in time, and the Mass Spectrometry, which provides information that aids in the structural identification of each component.

GC/MS in MH 353 is a Varian Saturn II equipped with a 3410 Gas Chromatograph and a Varian 8200 Autosampler. The instrument has been autotuned by the lab instructor.

Procedure Outline (specific to Varian Saturn II):

After filtration, cap the autosampler vial with the septum. This labeled vial is then placed in the autosampler. The computer screen is now showing what is known as the Main Executive Page.

1.0 Creating Analysis List

1.1 Click on Analysis.

1.2 In the analysis window click on File. Choose "Retrieve Analysis List".

1.3 Type "C:\KINGSTON\SEJAL. Hit "OK."

1.4 Click on an existing file and hit "Add" (Bottom left hand corner of the screen). Highlight (by single left click of the mouse) the added file. Click "Edit" (Next to the "Add" button).

1.5 Type "C:\KINGSTON\SEJAL"

1.6 Type ESM552S1 in the DataFile field (for ESM 552 Sample 1).

1.7 Put in a sentence in the Comment field that describes the sample in more detail.

1.8 Click on vial. Click <Edit> and change to appropriate number as (Rack number, Vial number).

1.9 Click <File>. Select "Save Analysis List As". Type in ESM 552.

2.0 Creating a GC Method

2.1 While on Analysis Page, highlight (i.e., left single click) GC Method followed by <Edit>

2.2 Click "Start temperature" of the first segment. Change figure to 80 degrees C. Hold at this temperature for 3 minutes. (Starting temperature will depend on the solvent used. Please consult lab instructor for a decision on the start temperature.). Change the figure in the "Rate" column to 0 degrees C/minute.

2.3 Start temperature of the subsequent segment should be the same as the "End Temperature" of the previous segment. (In this example, Segment 2 Start temperature will be 80 degrees C. Final temperature should never exceed 270 degrees C. Enter the Rate as 10 degrees C/minute.

2.4 Hold at this temperature for 2 minutes (Rate 0 degrees C/minute)

2.5 Injector port and transfer line should be changed to (if they are not already showing) 260 degrees C each.

2.6 Click <File>. Select "Save GC Method As". Type ESM 552

2.7 Click <Exit> (top right hand corner of the screen).

3.0 Creating an Aquisition Method

3.1 In the Analysis Page, highlight MS method. Click <Edit>.

3.2 Enter 45-400 as values for mass range.

3.3 Scan Rate should be entered as 1 sec/scan

3.4 Enter a value in minutes for Filament Delay Time (minimum six minutes). This value will depend on the solvent and start temperature of the first segment in the GC Method created in the previous step. Please consult the lab instructor for a correct value.

3.5 Enter a value in minutes for the Filament Length. (This is the total time taken by the GC Method in the previous step-24 minutes in this particular case).

3.6 Background Mass should be set at 45 amu.

3.7 Click <File>. Select "Save MS Method As". Type ESM 552

3.8 Click <Exit> (top right hand corner of the screen).

4.0 Creating an AutoSampler (AS) Method

4.1 In the Analysis Page, highlight AS method. Click <Edit>.

4.2 Click on "User-Defined" in Sampling Mode

4.3 Sample volume (if different) should be changed to 1.0ml

4.4 Set the Needle Penetration Depth at 85% (for vials with inserts, do not exceed 75%)

4.5 Click <File>. Select "Save AS Method As". Type ESM 552

4.6 Click <Exit> (top right hand corner of the screen).

5.0 Expanding the Analysis List

5.1 (Analysis List can be expanded to include a total of 200 entries). In the main display of the Analysis Page, click the first file to highlight it.

5.2 Click on <Expand> on the bottom of the display. A dialog box appears.

5.3 Enter a number equal to the total number of samples.

5.4 Click on OK to return to the main display. This list will now show as many entries as you have entered for expansion of the list. The datafiles will be named "ESM552S1, ESM552S2, ESM552S3, ƒwhich have identical GC, AS and Acquisition Methods, but have different rack and/or vial numbers.

6.0 Creating End Method

6.1 (This is to put the instrument in stand-by after your run is complete.) Click on the last datafile and <Add> followed by <Edit>. Name this last data file as "End".

6.2 Change the GC temperature to read the following: Oven temperature in the first segment: 150 degrrees C for one minute. Injector 250 degrees C, Transfer Line 250 degrees C.

6.3 Leave your valid Autosampler program. Delete entry for rack and vial number.

6.4 Change MS Method to read Acquire Time: 0 minutes, Filament Delay 0 minutes, Cal Gas Off and a valid mass range and scan time.

7.0 Starting Acquisition

7.1 In the main display of the Analysis Page, click <Utilities>. Select "Check All Entries". The software will go through all the datafiles you have created and check them for any potential errors or for overwriting. The program will detect an existing "End" File. Click on Overwrite. If all entries are valid, you will get a message, "Successful Entries". It is safe to begin the run now!

7.2 Click <Control>. Select "Start AutoSampler Run". The instrument will start the acquisition on its own.

8.0 Data Analysis

8.1 After Acquisition is complete, the screen will return to the main display of the Executive Page. Click on File Manager. Click on Kingston, Sejal and finally ESM 552. Select the file from the right hand column that you wish to analyze.

8.2 Hit F2 once and the Return Key twice to bring up the chromatogram.

8.3 Move the cursor with the arrow keys to the desired peak in the chromatogram. Hit F5. This will bring up the mass spectra of that point in the peak where the cursor is. Hitting Enter now will commence a Library Search.

8.4 Hitting <R> after the Library Search is over will bring up the report with the matches and identification of your compound.

Sample Preparation:

Sampling Information:

River water samples were taken and cooled to preserve prior to analysis. In general there are four types of water analysis:

• Total elemental content
• Dissolved elemental
• Particulate elemental, and
• Leachable elemental

This analytical exercise will focus on the dissolved portion which is most like the text evaluations we studied of classical water systems.

10 ml of each samples will be cold filtered through a 0.45 µm syringe filters.

Figure 1. generalizes the filtration equipment consisting of a syringe, filter and beaker.

ICP-MS analysis procedures for instrumental operation will be discussed in a separate portion of the laboratory documentation.

If total or leachable solids was also desirable or necessary, EPA RCRA Method 3015A microwave sample preparation would also be performed

ICP-MS analysis will be discussed in the laboratory.

Ye Han (laboratory instructor for ICP-MS)
The instrument will be run in the semi-quantitative measurement mode by your laboratory instructor and by you. The semi-quantitative mode will permit a measurement of most elements to within 10-20%.

Before your experiment, the ICP-MS instrument has been tuned and calibrated using a 10 ppb Li, Y, Ce, Tl solution.

Procedure Outline Specific to HP 4500 Software Prompts and Commands:

1. Edit specified method

1.1 In ICP-MS Top window, choose "Method" >> "Edit Entire Method" then click "OK"

1.2 In "Edit Method" window, select "Method Information" and "Acquisition", then click "OK"

1.3 In "Method Comment" window Type the method information you want to input Select "Data Acquisition" and "Data Analysis", leave others un-selected Click "OK"

1.4 In "Interference Equation", leave every item unchanged, then click "OK"

1.5 In "Acquisition Mode', only select "Spectrum", then click "OK"

1.6 In "Spectrum Acquisition Parameters",
Input "Integration time per Point" as "1" [sec] and "Repetition" as "1"
Leave "set every mass" blank
Click "Semi Quant (6)"
Click "Period Table"
The period table will appear. Click "Clear All" then select the 26 metals that list in Method 3052, as well as Scandium, by clicking the each element icon( turns red).
After select all of the 27 elements, click "OK"
click "Check parameters", if NO error, click "OK"
click "OK"

1.7 Set "Uptake Speed" as "0.5"rps, "Uptake Time" as "10" sec and "Stabilization Time" as "30" sec. Click "OK"

1.8 Save the Method as "Riversmp.m"

Now, you are ready to run your blank (for blank subtraction). When you analysis the filtered river water, the blank is pure DDI water. When you analysis the digested river water, the blank is digested mix-acids (5ml HNO3 + 1ml HCl in 45ml DDI H2O) which are used to digest water sample.

2. Insert sample uptake tubing into your blank solution

3. Acquire Blank Data

3.1 In the "ICP-MS Top" window, choose "Instrument >> Instrument Control"

3.2 In "ICP-MS Instrument Control" window, Choose "Plasma" >> "Plasma ON", then click "Yes"
        It will take about 2 minutes to settle the vacuum and
        ignite the plasma. You will find the instrument changes
        to "Analysis Model" from the "Standby Model".
        Close the "ICP-MS Instrument Control" window by clicking "x"
        at the upper-right corner of the window.

3.3 In the "ICP-MS Top" window, choose "Acquire Data" >> "Main Panel"

3.4 In the "ICP-MS Acquisition" window, choose "Acquire Data" >> "Acquire Data"

3.5 In the "Acquire Data" window,
Input "Data File Name" as "C:\EMS\group1\blank.d"
(for group2, save file as "C:\EMS\group2\blank.d")
Input "Sample Name" as "blank, DDI water"
(for group2, input "blank, mix-acids")
Input"Operator Name" if you like
Input "Dilution" as "1.00"
Leave "Misc. Info" blank
Click "Acquire".

Your blank will be run. It will take about 4 min.

4. Acquire Sample Data

4.1 When "Acq has finished", remove the sample uptake tubing from the blank solution and put it into the river water sample #1.

4.2 Choose "Acquire Data" >> "Acquire Data" again

4.3 In "Acquire Data" window
Input "Data File Name" as "C:\EMS\group1\sample1.d"
(for group2, save file as "C:\EMS\group2\sample1.d")
Input necessary sample information in "Sample Name"
Input "Operator Name" if you like
Input "Dilution" as "1.00"
Leave "Misc. Info" blank
Click "Acquire"

4.4 When "Acq has finished", remove the sample uptake tubing from the sample solution and put it into the 2% HNO₃ rinsing solution.

5. Blank Subtraction and Data Analysis

5.1 In "ICP Data Acquisition" window, click "Data Analysis" icon. The "ICP-MS Data Analysis" window will appear.

5.2 Choose "SemiQuant" >> "Blank Subtraction"
Select "Blank Conc. Subtraction"
Click "Browse"
Type "C:\ems\group1\blank.d" (for group2, type "C:\ems\group2\blank.d")
Click OK
Click OK again

5.3 Choose "SemiQuant" >> "Generate report"

5.4 In "SemiQuant Report Option" window, select "Screen" and "Printer", then click OK It will take 1 or 2 minutes to generate your final report and print out.

5.5 In "Tmpqutrp.txt" window,
Select "File" >> "Save"
Click "Save"
Close "Tmpqutrp.txt" window by clicking "Ç" at the upper-right corner of the window

6. Minimize "Data Analysis" window by clicking "_" at the upper-right corner of the window

7. Remove the sample uptake tubing from the 2% HNO₃ Rinsing solution and put it into next river water sample. Repeat step 4.2, 4.3, 4.4, 5.1, (skip 5.2), 5.3, 5.4, 5.5 and 6

8. Repeat step 8 for the rest of samples.

9. Congratulations! Experiment is finished.

Environmental Modeling and Evaluation Project

This is a "Cooperative Learning Project"

An overview of environmental Modeling will be covered in class but familiarization with these modeling concepts will primarily be gained through your cooperative learning group projects. Your use and testing of the model specific to your project.

Because of the complexity of environmental chemistry these are very important tools that you will need to learn to use, evaluate and demonstrate. You are permitted to take a computer copy of all of these models as they are government models and not subject to copyright. These are tools you will use in your careers and having and knowing how to use them will be a definite advantage in your job search or your employment. RiskPro is the only except - a commercial version, to which there are several EPA versions that are not copyright protected.

Specific topics in environmental modeling and evaluation will be covered through the participation and presentation in the class by these cooperative learning groups. Projects will be assigned/chosen to(by) groups of student (6-9 students per group) who will work cooperatively to develop the concepts as a class presentation and as a research paper.

This is a self and group directed study and you will learn as much as you desire and work at these concepts. Extend yourself and your group as a professional in the area of environmental science and make the most of this learning opportunity.

Choose a cooperative learning groups of 6-9 members (depending on the class size) based on interest in the roughly 5-7 types of models that are recommended to the class. There are others available but these have been chosen as the most appropriate and most cooperative with standard computer platforms and common computer skill levels.

You will evaluate each others participation and you will assign each other portions of the grade factor based on you quality of participation.

The Project Assignment

Your entire group will be responsible for the group project.

You may break the task down into sub-tasks for subgroups if your project lends itself to this approach.

Everyone must learn to run the model and participate in preparation of the paper and class presentation but you may specialize other portions of the project. This does not mean that everyone should participate in the presentation in class except for questions and answers.

a. Integration of fundamental concepts related to the model:

You will coordinate the pertinent text subject matter with the modeling parameters to demonstrate how the model adequately or inadequately or in a defined way represents the area of environmental chemistry. You should assign additional reading in the text and identify the concepts that the model covers. Give page numbers and text sections that relate. Provide other concepts that are not covered in the text that are key aspects of the model theory.

Give specific equations that related to specific parameters and concepts and describe how they adequately or inadequately describe the parameter. Describe the limits of useful parameter range and situation.

Students should use the literature and find other significant references that discuss the concepts and the algorithms that are used to represent them if possible. These should be referenced in a scholarly scientific manner.

b. Evaluation of the model:

Evaluate the models effectiveness at predicting the parameters in environmental chemistry. Provide examples that were tested by the group. You should evaluate the model providing output data form model tests developed by the group to test the capability, accuracy, effectiveness or limitations of this model.

A set of test situations should be programmed by the group and evaluated. These should be well designed to test the models capability to evaluate and handle real world scenarios. These data should be reported on as part of the class presentation. The class will evaluate the thoroughness of the evaluation and appropriateness of the test.

Your group should evaluate and describe the limitations of the model and provide understanding of how these limitations are related to fundamental parameters the model is trying to emulate and describe.

c. Class presentation

The group (or selected members of the group) will present a presentation on the model featuring a. Integration of fundamental concepts in the model and b. Evaluation of the model. You will also integrate how the model conforms to model concepts that have been discussed in class including key features of importance and relevance as decided by the group and in consultation with the instructor. The group will design the lecture to be instructive to the class and to bring them into familiarity with the concepts of your groups model.

The groups will have approximately 30 minutes for this organized presentation and will entertain questions from the class and instructor. The presentation should be organized, use multimedia (such as PowerPoint multimedia). Approximately 10 -15 minutes of questions by the class will follow and in-depth understanding of the concepts covered by the model will be expected by the group. The PowerPoint presentations and paper should be handed in on disk in addition to a hard copy. These presentations will be mounted on the Web if they are of appropriate quality.

A handout should be prepared for the presentation for the class. Literature references will be sighted to provide the origin of the information and extent and scope of evaluation.

The concepts covered in the group presentation will be included into the course material and will also appear on exams.

d. Group paper organizing the parameters a., b., & modeling concepts

The paper will be approximately 8-12 pages double spaced text (not counting table, figures, table of content, references or approved appendices) discussing the conceptual topics and related theory and chemistry and the evaluation. The specific model(s) will be evaluated. Its scope, relevance and limitations that have been evaluated and tested will be clearly discussed.

Photo copies of the three primary references (other than the assigned texts and computer models) will be handed in with the paper.

Computer modeling data taken with the model in its evaluation and demonstration will also be submitted.

First Class modeling Assignment - done in class

Choose your cooperative learning group and partners.

Choose your specific computer model(s) and begin familiarity

Presentation, Paper Organization,
and Evaluation Elements Desired

Prepared as if this presentation were a lecture and report to an environmental group for instructional purposes on environmental scientific issues.

Additional instructions:

Assignments of related textbook material will be made by cooperative learning groups relating your concepts.

Where a portion of the textbook is necessary for a complete understanding of the concepts you will be describing. You with the consensus of your cooperative learning group will assign this portion of the textbook (or paper if necessary) the week prior (or tow weeks if possible) to your presentation. You will be directing your classmates to chapters and sections of chapters they need to read prior to your presentation. Everyone will familiarize themselves with these concepts to assist with understanding. They will then ask intelligent, insightful and probing questions demonstrating understanding of the topic you have presented and they have read about. All assignments will be considered covered for purposes of discussion, questions and for the final exam. Be specific in your assignments giving page numbers and chapter sections. Then describe how these topics and concepts relate to your model or why they were important as background material.

Elements to be considered in making the presentation and paper preparation

• Thoroughness of evaluation of the models

• Comparison and contrast of appropriate aspects of models

• Clarity of issues identified and appropriateness of issues identified in the evaluation

• Appropriate sampling of chosen environmental medium proposed and evaluated

• Demonstration of the most appropriate model and appropriate scenario derived by group

• Awareness of issues that are important

• Scope of issue of problem
  Appropriate identification of key issues, problems, resources, methods etc.

• Depth
  Case facts and data effectively marshaled, developed, and related to argument

• Breadth
  Argument is thorough and comprehensive

• Analysis
  Evaluation of interrelationships and concepts

• Structure
  Argument is well-ordered. Clear and apparent logic. Key relationships identified within and between topics

• Recommended approach for solution
  Compiled solutions with analysis for solving the identified problem areas

• Presentation Mechanics
  Transparencies, are simple, clear and effective -- and are effectively used.

• Presence
  Presenter(s) lends vitality, enthusiasm, and force to the argument.

• Overall evaluation
  Excellent, persuasive, convincing or Poor, weak, unconvincing.

• Support documentation and references
  Appropriate use of literature, documentation and opinions

• Outside literature should be consulted
  Outside literature should be consulted and used to support opinions if they are available and appropriate

• Textbook Coordination
  Investigate the topics from the text that relate to your model
  Coordination these into your instruction of your model
  A Key and Appropriate paper may also be recommended
  

Grading of Presentation and Paper

• Criterion

• Content

• Organization

• Quality Factor

• Other criteria as listed above

• Presentation & Neatness (electronic presentation and professionalism)

• Example printed out for each model tested and evaluated, Power Point Presentation with outline and model examples

paper due at your presentation

The individual grade will be weighted according to your contribution. Peer evaluations will be used

Group decides who presents; entire group is responsible for the final product and the final grade one or more may present all will handle questions from the class and the instructor

Abstracts for the Models for Environmental Chemistry Course 552

Air Models

Toxic Air Pollution Screening Model (TSCREEN). The continuing involvement in the Superfund toxic/hazardous pollutant impact activities has created a need for easy to use air quality screening modeling techniques. Pacific Environmental Services, Inc. (PES) has developed TSCREEN, A Model for Screening Toxic Air Pollutant Concentrations. This computer program implements the procedures in the workbook and is a screening model that can be easily used by State and local agencies. To correctly analyze toxic emissions and their subsequent dispersion from one of many different types of possible releases from Superfund sites, the computer program TSCREEN should be used in conjunction with the workbook. With the use of these tools one can determine the type of release and what steps are to be followed so that the release can be simulated via an applicable computer model and then the dispersion characteristics and pollutant concentrations of the resulting plume calculated. The air toxics dispersion screening models imbedded in TSCREEN that are used for the various scenarios are SCREEN, RVD, and PUFF. Using TSCREEN, a particular release scenario is selected via input parameters, and TSCREEN automatically selects and executes the appropriate dispersion model to simulate that scenario. The model to be used and the appropriate worst case meteorological conditions are automatically selected based on criteria given in the workbook. TSCREEN has a front-end control program to the models that also provides, by use of interactive menus and data entry screen, the same steps as the workbook. The correct release scenario and associated characteristics of a toxic emissions release are selected with the help of on-screen text; graphics and data input is performed in a full-screen edit mode. TSCREEN saves the input data for each release scenario to a file that can be retrieved and later edited or executed. TSCREEN also provided a method of easily viewing and saving the modeling results for each modeled scenario.

The Industrial Source Complex Model (ISC) is a steady-state Gaussian plume model which can be used to assess pollutant concentrations from a wide variety of sources associated with an industrial source complex. This model can account for the following: settling and dry deposition of particles; downwash; area, line and volume sources; plume rise as a function of downwind distance; separation of point sources; and limited terrain adjustment. ISC is appropriate for the following applications: industrial source complexes; rural or urban areas; flat or rolling terrain; transport distances less than 50 kilometers; one-hour to annual averaging times; and continuous toxic air emissions. It operates in both long-term (ISCLT) and short-term (ISCST) modes. ISCLT is included as a part of EPA's PC Graphical Exposure Modeling System (PCGEMS) [the same program as the comercial version, RISKPRO, by General Sciences Corporation (GCS)].

Groundwater and Soil Models
Unsaturated/Vadose Zone

VLEACH (1-D Finite Difference Vadose Zone Leaching Model) is a one-dimensional finite difference model designed to simulate the leaching of a volatile, sorbed contaminant through the vadose zone. (Although the term "contaminant" is used throughout this guide, VLEACH could be used to model the transport of any non-reactive chemical that displays linear partitioning behavior). It models four main processes: liquid-phase advection, solid-phase sorption, vapor-phase diffusion, and three-phase equilibration. In its current version, VLEACH is subject to a number of major assumptions:

• Contaminant partitioning between phases follow linearrelationships, i.e., both KD and KH are constants.
• The three phases present (liquid, vapor, sorbed) are in astate of equilibrium in each cell.
• The moisture content profile within the vadose zone is constant , i.e., the vadose zone is in a steady state with respect to water.
• Liquid-phase dispersion is neglected.
• No "free product" is present.
• The contaminant is not subject to in situ production or degradation.
• The vadose zone soil within a particular model polygon is completely homogeneous, and behaves as a uniform porous medium, with no preferential pathways to flow.
• Volatilization from the soil surface is either completely unimpeded or completely restricted. Some of these limitations may be relaxed in future versions of VLEACH.

CHEMFLO (1-D Water and Chemical Movement in Unsaturated Soils) was developed to simulate the movement of water and chemicals in unsaturated soils. Water movement is modeled using Richard's Equation. Contaminant transport is modelled using the convective-dispersion equation. These equations are solved numerically for one-dimensional flow and transport using finite differences. Results of the modelling can be displayed as graphs of water content, matrix potential, driving force, conductivity, flux density, or chemical concentration over distance and time. Soil profiles are assumed to be homogeneous.

The Regulatory and Investigative Treatment Zone Model (RITZ) simulates the movement and fate of hazardous chemicals during land treatment of oily wastes. The model incorporates the influence of oil in the sludge, water movement, volatilization, and degradation upon the transport and fate of a hazardous chemical. The model assumes that the waste is uniformly mixed in the plow zone, and that the oil in the waste is immobile. It is also assumed that soil properties are uniform from the soil surface to the bottom of the treatment zone. Water flux is also assumed to be uniform throughout the treatment site and through time. Hydrodynamic dispersion is assumed to be insignificant. The model accounts for first order degradation of the pollutant and oil.

SOILCS, SOILSS, SOILUS, and TRANS1D are EXCEL 5.0 programs which determine transport and fate of organic chemicals in soil and groundwater. These models are screening-level models, which, because of their facility of use, can provide rapid assessment of the behavior of organic chemicals in contaminated soil and groundwater. SOILCS, SOILSS, and SOILUS simulate the behavior of organic chemicals in soil. The programs calculate chemical partitioning within the soil compartment and losses of the chemical from the soil due to degradation, leaching, vapor extraction, or volatilization. The soil phases considered are air, water, and solids (consisting of mineral matter and organic matter). Equilibrium relations are used to calculate the partitioning of the organic chemical into the soil vapor phase, the soil aqueous phase, and solid organic matter in the soil. Additionally, the organic chemical may be present as a non-aqueous phase liquid (NAPL). The three programs provide the capability of modeling a closed soil system-no reaction, leaching, vapor extraction, or volatilization (SOILCS), an open soil system at steady state (SOILSS), or an unsteady, open soil system (SOILUS). TRANS1D is a one-dimensional groundwater soulte transport program. The processes considered include advection, dispersion, degradation, and sorption of organic solutes.

Groundwater Models

BIOPLUME II (2-D Contaminant Transport Under the Influence of Oxygen Limited Biodegradation in Ground Water) is a two-dimensional model which simulates the transport of dissolved hydrocarbons under the influence of oxygen- limited biodegradation. BIOPLUME II also simulates reaeration and anaerobic biodegradation as a first order decay in hydrocarbon concentrations. The model is based on the USGS 2-D solute transport program. The model computes the change over time due to convection, dispersion, mixing, and biodegradation. BIOPLUME II solves the solute equation twice: once for hydrocarbon and once for oxygen. As a result, two plumes are computed for every time step. The model assumes an instantaneous reaction between oxygen and hydrocarbon to simulate biodegradation processes. The two plumes are combined using the principle of superposition. The model can simulate natural biodegradation processes, retarded plumes, and in-situ biorestoration schemes. The model also allows injection wells to be specified as oxygen sources into a contaminated aquifer.

EPA-WHPA is a modular, semi-analytical groundwater flow model designed to assist with the task of Wellhead Protection Area (WHPA) delineation. The model consists of four independent computational modules that are used to delineate capture zones. Three modules contain semi-analytical solutions, applicable to homogeneous aquifers that exhibit two-dimensional steady groundwater flow in an areal plane. Multiple pumping and injection wells may be present. Barrier or stream boundary conditions which exist over an entire aquifer depth may be simulated. One of these three modules is a Monte Carlo simulation which allows the effect of uncertain input parameters on the delineated capture zone(s) to be assessed quantitatively. The fourth module is a general particle tracking simulation which can be used as a postprocessor for two-dimensional numerical models of groundwater flow.

Surface Water Model

The object of the expert system is to provide the analyst with accurate and reliable predictions of the discharge mixing process. The expert system should be easy to use and should allow for preliminary mixing zone analysis of a typical design in perhaps 20 minutes if all necessary input data is available. Emphasis is placed on the geometry and initial mixing of the discharge, along with prediction of concentration (or dilution) values and the shape of the regulatory mixing zones. The expert system should provide the analyst with detailed hydrodynamic information and recommendations for discharge design including sensitivity studies.

Since its emphasis is on initial mixing mechanisms with their short time scales, CORMIX assumes a conservative pollutant or tracer in the effluent. Thus any physical, chemical, or biological reaction or decay processes are neglected. However, if first-order processes are assumed the predictive results can be readily adjusted to include such processes. It seems impossible, and probably unnecessary, to develop a system that works reliably for every conceivable mixing zone and discharge configuration. The present philosophy, however, was to develop an expert system that works for the large majority (better than 95%) of typical discharges, ranging from simple to fairly complex cases. The remaining cases may require separate analyses, perhaps using sophisticated numerical modeling or a detailed hydraulic model study.

Nonpoint Source Model

Response Model

Peer Evaluation Form

Important note: this rating is confidential. Dr. Kingston is the only person other than you who will see it and he will not reveal any individual's rating to anyone.

Instructions: List and rate every member of your group, including yourself, on overall contribution to the group projects. Use the following rating scale:

5.         Contributed much more than her/his share.

4.         Contributed a little more than her/his share.

3.         Contributed her/his share (neither more nor less).

2.         Contributed much less that her/his share.

Group Members....................Rating....................Assigned Group #

Person filling out this evaluation (self-evaluation):

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Other group participants names.....Circle the appropriate category

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The topic of our group project was _______________________________

Comments are optional; write them below or on the back of this sheet.

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Revised 4/15/99