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
1.
Obtain brine shrimp
2.
Label petri dishes 0%, 10%, 20%, 30%, 40%, and 50%
3.
Place 10mL of water in the 0% petri dish
4.
Place 9mL of water in the petri dish labeled 10% and then add 1mL of bleach
5.
Place 8mL of water in the petri dish labeled 20% and then add 2mL of bleach
6.
Place 7mL of water in the petri dish labeled 30% and then add 3mL of bleach
7.
Place 6mL of water in the petri dish labeled 40% and then add 4mL of bleach
8.
Place 5mL of water in the petri dish labeled 50% and then add 5mL of bleach
Procedure
9. Add 30 brine shrimp to each petri dish
10. Let shrimp sit in water for 5 minutes
11. Count how many shrimp are still alive in each
concentration of the toxin
12. Record data and behavior
13. Compare results
14. Repeat steps 2-14 for each toxin
Data
Data
Data
Number of Shrimp Alive after 5 minutes
35
30
25
20
Detergent
Lysol
15
Bleach
10
5
0
0%
10%
20%
30%
40%
Concentration of Toxin (%)
50%
60%
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?