The LD50 of Common Household Toxins on Brine Shrimp Kailin Edgar May 17th, 2012
Brine Shrimp • Tolerate a salt content of between 25 and 35% salt • Can be found in salt flats • Important food source to many wildlife species • Indicators of pollution within water bodies
LD50 • 50% of an organism is killed by a specific concentration of a toxin • Higher threshold=withstand higher concentrations
Problem • What is the LD50 of common household toxins on brine shrimp?
Hypothesis • If Brine Shrimp are placed in various concentrations of common household toxins such as Lysol, bleach, and laundry detergent then the bleach will be the most harmful product and the laundry detergent will be less harmful (shrimp will have the highest tolerance for the laundry detergent).
Materials • 1000 ml beaker • Eye droppers • 10 ml pipettes • Graduated cylinders • Small petri dishes • Beakers • Stop watch • Live brine shrimp • Pipump • Lysol • Bleach • Washing Detergent
Procedure • Obtain brine shrimp • Label petri dishes 0%, 10%, 20%, 30%, 40%, and 50% • Place 10mL of water in the 0% petri dish • Place 9mL of water in the petri dish labeled 10% and then add 1mL of bleach • Place 8mL of water in the petri dish labeled 20% and then add 2mL of bleach • Place 7mL of water in the petri dish labeled 30% and then add 3mL of bleach • Place 6mL of water in the petri dish labeled 40% and then add 4mL of bleach • Place 5mL of water in the petri dish labeled 50% and then add 5mL of bleach
Procedure • Add 30 brine shrimp to each petri dish • Let shrimp sit in water for 5 minutes • Count how many shrimp are still alive in each concentration of the toxin • Record data and behavior • Compare results • Repeat steps 2-14 for each toxin
Data Number of Shrimp Alive after 5 minutes Concentration of Toxin (%)
Discussion • Hypothesiswassupported • Bleachwasthemostharmfultoxin killed more thanhalf of theshrimppopulation in a 10% concentration • Lysolwasverytoxicbutthresholdwashigher more than 50% werekilled in a 20% concentration • Washingdetergentwasleastharmful LD50 wasbetween 40-50%
Sources of error • LD50’s are not exact because concentrations were spread apart • Determining whether the shrimp were still alive was difficult and counting the same shrimp twice was very possible
Conclusion • Householdproducts can be verytoxic • Small marine animalsexposedtosmallconcentrations of a productmay be killedortheirswimmingseverlyaffected
Future Implications • Theeffect of householdtoxinsonlarger marine animals • New, environmentallysafeproducts can be inventedtotakethe place of thesetoxinswithoutcausingthesameeffects • Waystoexpose of thesetoxins keepthemout of thewater