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 Stop watch Eye droppers Live brine shrimp 10 ml pipettes Pipump Graduated cylinders Lysol Small petri dishes Bleach Beakers 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

Data

Data Number of Shrimp Alive after 5 minutes Concentration of Toxin (%)

Discussion Hypothesis was supported Bleach was the most harmful toxin killed more than half of the shrimp population in a 10% concentration Lysol was very toxic but threshold was higher more than 50% were killed in a 20% concentration Washing detergent was least harmful LD50 was between 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 Household products can be very toxic Small marine animals exposed to small concentrations of a product may be killed or their swimming severly affected

Future Implications The effect of household toxins on larger marine animals New, environmentally safe products can be invented to take the place of these toxins without causing the same effects Ways to expose of these toxins keep them out of the water

Questions?