Dredging in St. Paul watershed

http://www.watersheddistrict.org/
html-newsletters/2005/march/Wade.htm

Should we try to remove contaminated sediments and risk polluting the water?

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Grade Level	7-12
Subject Area	Earth systems, chemistry, geology, biology, environmental issues
Standards	This activity satisfies portions of the following National Science Education Standards for grades 7 through 12. Additional information about the NSES can be found at the following web address: http://www.nap.edu/html/nses/ Science as Inquiry [grades 6-8] Different kinds of questions suggest different kinds of scientific investigations. Technology used to gather data enhances accuracy and allows scientists to analyze and quantify results of investigations. Scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories. Science and Social Perspectives [grades 6-8] Human activities can induce hazards through resource acquisition, urban growth, land-use decisions, and waste disposal. Such activities can accelerate many natural changes. RISKS AND BENEFITS Risk analysis considers the type of hazard and estimates the number of people that might be exposed and the number likely to suffer consequences. The results are used to determine the options for reducing or eliminating risks. Students should understand the risks associated with chemical hazards (pollutants in air, water, soil, and food). Individuals can use a systematic approach to thinking critically about risks and benefits. Examples include applying probability estimates to risks and comparing them to estimated personal and social benefits. Important personal and social decisions are made based on perceptions of benefits and risks. Science and Technology [grades 9-12] ABILITIES OF TECHNOLOGICAL DESIGN IDENTIFY A PROBLEM PROPOSE DESIGNS AND CHOOSE BETWEEN ALTERNATIVE SOLUTIONS IMPLEMENT A PROPOSED SOLUTION EVALUATE THE SOLUTION AND ITS CONSEQUENCES COMMUNICATE THE PROBLEM, PROCESS, AND SOLUTION Science and Social Perspectives [grades 9-12] Humans use many natural systems as resources. Natural systems have the capacity to reuse waste, but that capacity is limited. Materials from human societies affect both physical and chemical cycles of the earth. Natural and human-induced hazards present the need for humans to assess potential danger and risk. Ohio Science Education Standards: The activity meets the following Benchmarks for academic content. For specific standards visit the web site http://www.ode.state.oh.us/academic_content_standards/ Earth System Science Grades 6-8. C. Describe interactions of matter and energy throughout the lithosphere, hydrosphere and atmosphere. Grades 11-12. B. Describe how Earth is made up of a series of interconnected systems and how a change in one system affects other systems. C. Explain that the choices humans make today impact natural systems in the future. Life Science. Grades 11-12. B. Explain how humans are connected to and impact natural systems. E. Explain the interconnectedness of the components of a natural system. F. Explain how human choices today will affect the quality and quantity of life on earth. Science and Technology. Grades 11-12. A. Predict how human choices today will determine the quality and quantity of life on earth. Scientific Inquiry Grades 6-8. B. Analyze and interpret data from scientific investigations using appropriate mathematical skills in order to draw valid conclusions. Grades 11-12. A. Make appropriate choices when designing and participating in scientific investigations by using cognitive and manipulative skills when collecting data and formulating conclusions from the data. Scientific Ways of Knowing Grades 6-8. A. Use skills of scientific inquiry processes.
Earth Systems Understandings [click HERE for explanation]	#2 -- Human activities, collective and individual, conscious and inadvertent, affect planet Earth #3 -- The development of scientific thinking and technology increases our ability to understand and utilize Earth and space #4 -- The Earth system is composed of interacting subsystems of water, rock, ice, air and life #7 -- There are many people with careers that involve study of Earth’s origin, processes and evolution.
Length of Activity	Activity 1: one class period Activity 2: one - two class periods
Materials Needed	Computer access, Internet connection, podium
Prior Knowledge Needed	Part 1 Students should have a prior understanding of pollution and how pollution enters the environment. It may also be beneficial for students to know about concepts such as turbidity, water column, sedimentation, and habitat remediation. Part 2 Students should have an understanding of the process of bioaccumulation and the effects it can have on higher level consumers in the food chain. It would also be beneficial for students to know how to make concept maps and work cooperatively in groups.
Objectives	When students have completed these activities they will be able to: * Describe methods for removing contaminated sediments from the environment * Model the process of dredging contaminated sediments * Evaluate data to determine the success of dredging * Make a decision based on scientific data * Develop a concept map
Data Sets	Downloadable pages of data: Tables of PAH change over time in river sediments, and percentage of brown bulleads with liver lesions. To understand the data, students will need to examine the key words in their Part 2 Worksheet.
Introduction	This lesson has two activities. Each activity can be used separately as a supplement to existing curricula on bioaccumulation and environmental pollution, or can be used together as a complete curriculum insert. The following text will describe the lesson in detail and will provide the student activity sheets and data necessary to utilize these activities in your science classroom. It may be helpful for you to read the EPA report on how dredging of the Black River affected the prevalence of fish tumors: http://www.epa.gov/glnpo/sediment/Bullhead/report.html
Background	Toxins are threatening the fauna (including humans) in many aquatic ecosystems. Efforts are underway to reduce the amount of toxins being released into the environment, however, the problem of what to do with toxins already in the environment has become a pressing issue. The student Worksheets contain background information for each activity.
Procedure	Activity 1 Student Procedure handout. Activity 1 Teacher Notes: Show the Dredging Sediments Powerpoint introduction for student orientation to the task. Show the Dredging Sediment Powerpoint (317kb ppt file) introduction for student orientation to the task. You will need to set up the lab the day before so that the soil has time to settle in the dissecting pans. If advance preparation is not possible then use sand. It settles out in a few minutes, but dredging is not dramatic. Instruct students to be careful when moving the pans so they do not disturb the clay sediment on the bottom. Jigsaw: Students could be divided into expert groups where each group models a different type of dredging then returns to a base to group to share the results. It may be easier to have a general class discussion after the activity in lieu of doing the lab questions. Activity 2 Student Procedure handout Activity 2 Teacher Notes: This may be an activity for which you will want to have students remain in their expert groups to evaluate the data. It may be necessary to provide students with more information on the PROACT method for decision-making Students may need more guidance is this will be their first attempt at developing a concept map.
Conclusion	Answers to Activity Questions
Evaluation	Create a concept map for dredging toxic sediments based on the information in these activities. Make sure to include connections between the hydrosphere (water), lithosphere (sediments), and biosphere (living organisms). Rubric for concept map
Extension	Students could do a web search for more data on the effects of dredging in Ohio rivers and lakes to see if the new data would influence their decision-making process. Check for information about the Hudson River dredging controversies.
References and Resources	Baumann, P. and Harshbarger, J. (1996). Decline in liver neoplasms in wild brown bullhead catfish after coking plant closes and environmental PAH’s plummet. Environmental Health Perspectives. 103(2):168-170. Ashtabula River report updating toxin information: http://www.fws.gov/midwest/AshtabulaNRDA/ 2004 update on PCBs and HCBs in the Ashtabula River, from US Fish and Wildlife Service [pdf file]. Ohio EPA Website: http://www.epa.gov/glnpo/aoc/ashtabula.html
Author	Jeremy King, High School Science Teacher, Ohio Web assistance by Ann Froschauer and Rosanne Fortner

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From Decision Making Activities for the Great Lakes, Contaminated Sediments.
Developed by the Ohio Sea Grant Education Program, The Ohio State University. © 2003