Engaging the Student (Entry Task) 

Checking for Understanding (exit ticket)

~2 class periods 

•  As an entry ticket, ask students where they think sewer water goes after it is treated at a Waste Water Treatment Plant.
• Pass out a copy of the Bioassay Lab Instructions to each student and a copy the sample permit per  table group.
• Read through the beginning of the Bioassay lab as a class, then let students perform the "Turn & Talk" activity to explore the sample permit. 

• Bioassay Lab Instructions
• Sample Permit
• Bioassay Data Sheet
• Measuring volume with a syringe 

View the full lesson here:

Lesson 5-3 Conducting a Bioassay

If time allows, show students the following PowerPoint that describes their test organism, Daphnia magna, and why it is commonly used in Bioassay studies. NOTE: It's extremely important that students use the smallest daphnids possible as they do asexually reproduce!

• About Daphnia magna PPT

NOTE: The Reference Toxicant tests are more challenging, so you may want to assign students that are particularly good at following directions and attention to detail to the Reftox test. Often, students do not know how to properly measure volume with a syringe, so it's good to do a small tutorial with the Reftox groups (using the student handout provided) and have them draw out how they'll measure their quantity before they actually do it for the lab. Also, they need to be very careful when moving their test that the water doesn't slosh into the other test chambers. It only takes a little copper to kill the Daphnia.

For Class to Share:

• pH probes
• Thermometers
• DO Probes 

For each group conducting an "Effluent Test":

• Bioassay Lab Instructions
• Bioassay Data Sheet 
• 500 mL Final Effluent (can obtain from a local WWTP)
• 2 L Spring Water 
• Dissecting microscope
• 250 mL graduated cylinder
• 1 to 2 large plastic cups
• Sharpie
• 6 small test cups (small condiment cups are perfect)
• 1 mL plastic pipette (with tip cut off)
• Masking tape
• Test holder (a 6-cup egg crate works great)
• Cup of young (>24hr old) Daphnia magna 

For each group conducting a "RefTox Test":

• Bioassay Lab Instructions
• Bioassay Data Sheet 
• Measuring Volume with a syringe handout 
• 2 L Spring Water 
• Copper Sulfate (concentration of 200,000 ug/L) 
• 1 mL syringe
• Dissecting microscope
• 250 mL graduated cylinder
• 1 to 2 large plastic cups
• Sharpie
• 6 small test cups (small condiment cups are perfect)
• 1 mL plastic pipette (with tip cut off)
• Masking tape
• Test holder (a 6-cup egg crate works great)
• Cup of young (>24hr old) Daphnia magna