ENV U6220 THURSDAY, 7/28/05 – LAB #3: EXPOSURE ASSESSMENT PAGE 1 Name: _____________________________________ Lab 3: Exposure AssessmentExposure assessment requires numbers for intake of media: air, water, soil. Your task in this lab is to assess the water intake of the members of your class and compare the values to those recommended by EPA. As before, each individual will hand in this set of pages as the lab report, reflecting both individual and group work. I. Gather in a group of 4 to 6 people for your initial work.II. Read section 3.1 BACKGROUND (page 3-1) of the EFH reference document (EFH sect 3 drinking water.pdf) and answer the following question: For a national drinking water standard, EPA uses total fluid intake, while for a site-specific risk assessment, EPA recommends tapwater intake. Explain why.III. You will be determining tapwater intake rather than total fluid intake to keep the scope of work more manageable. To decide what information you need to gather from the class to assess tapwater intake, first browse the entire EFH document, and as you do so, list factors below about each person’s characteristics and water drinking. As a group, decide whether and how to include them in a survey. In drafting survey questions, keep in mind both ease of answering and ease of analysis. Factor Include / why or why not Draft of question if included (with units)ENV U6220 THURSDAY, 7/28/05 – LAB #3: EXPOSURE ASSESSMENT PAGE 2 IV. Choose one person from your group as a representative to the class-wide group to finalize the survey. a.If you are the representative:1. make sure your table on the previous page is complete and represents the consensusof your group2. meet with the other representatives and develop a final survey 3. prepare an Excel spreadsheet to enter the data from the survey and select a person todo the data entry4. print out 30 copies of the surveyb. Others in the group: plan how you will analyze the data1. study Table 3-30 (page 3-26) in the EFH document because that is what you will compare your results to2. use the web for information such as conversion factors (lb to kg, oz to ml, etc.) and calculation of 90th percentile values V. Each individual will complete the survey and immediately give it to the person doing data entry. As soon as the data entry is complete, this person should email the results to the whole class. (The spreadsheet should only contain data; each individual will modify the spreadsheet to convert the data units and calculate means, percentiles, etc.) Each of the two lab sessions will be generating results that will be emailed to everyone; you are only responsible for analyzing the results from your lab session.VI. The final part of this lab is analyzing the results from your lab session and comparing them to the recommended values in Table 3-30 in the EFH document. Depending on how efficiently the survey was developed, you may have time during the lab, or you may have to finish later. You may work with others to do the calculations but the report below must be in your own words. Present your calculations in a table and discuss them in narrative form. Identify any limitations of the present lab exercise and how these limitations affect the comparison to EPA’s recommended values. Use the back or attach another sheet if you need more space.ENV U6220 THURSDAY, 7/28/05 – LAB #3: EXPOSURE ASSESSMENT PAGE