Toxic Tea Lab
Date completed: 11/04/2015
Group Members: Michael, Mitchell, and Daniel
Group Members: Michael, Mitchell, and Daniel
Purpose:
After this lab, one should be able to explain the concept of toxicity and LC50, understand how LC50 is calculated and it's importance, along with being able to identify causes of poisoning in nature.
Pre-Lab Questions
- Benzaldehyde -- 4.32 g
- THC -- 9.9 g
- Ethyl Acetate -- 549 g
- Propylene Glycol -- 1814.37 g
- Caffeine -- 11.8 g
- Malic Acid -- 145 g
- Methanol -- 506.52 g
- Nicotine -- 17.1 g
- Botulinum Toxin -- 2.7 x 10^-9 g
- Potassium Nitrate -- 17.1 g
- Sodium Fluoride -- 4.68 g
- Parathion -- .54 g
- Vx -- 2 x 10^-5 g
- Tetrodotoxin -- .0302 g
- Diazinon -- 6.90 g
- Gamma Hydroxybutyrate -- 181 g
2. The MSDS tells us that nicotine is dangerous because it has a low LD50 of 50 mg/kg on rats. Nicotine is highly toxic and exposure through skin, inhalation and ingestion can lead to liver, kidney, lung injury, and reproductive harm. If exposed to nicotine in the lab, then one should flush the area of exposure with water for 15-20 minutes. If inhaled, move to fresh air. If ingested, one should induce vomiting. (Toxic Tea Lab Sheet)
3. Ethanol has an LD50 of 7060 mg/kg. Therefore a person weighing 90 kg, the LD50 would be 635.4 g.
MSDS Source:
http://www.officedepot.com/pdf/msds/134941.pdf
3. Ethanol has an LD50 of 7060 mg/kg. Therefore a person weighing 90 kg, the LD50 would be 635.4 g.
MSDS Source:
http://www.officedepot.com/pdf/msds/134941.pdf
Procedures:
- Retrieve all the materials one will need for this lab
- Create the stock solution for 10x, 7.5x, 5x, 2.5x, 1x, .5x, .1x, and 0x.
- After this step has been complete, transfer 10 brine shrimp into the test tubes using a pipette. Then to make sure there isn't any left over brine in the test tube, take out the left over brine in the test tube without taking out any shrimp.
- Then add the tea extract in each test tube.
- Let the test tubes sit for 24 hours and then collect data on how many shrimp survived in each test tube.
- Record the data and share with the class.
Data:
The LC-50 on the graph would be close to 10x concentration because that is around the needed concentration to kill off half the population.
Analysis Questions
- There is evidence of background death rate independent of the addition of herbal teas because in the lower concentration of toxic tea there were high death rates. It is not common for the lower concentration to have high mortality rates so those deaths can be determined as background death.
- The LC-50 for the class data on brine shrimp is the concentration 10x. One can tell the LC-50 by looking at the graph and seeing where half of the brine shrimp population dies. At the concentration 10x, 21 out of 40 brine shrimp died. This is the lethal concentration needed to kill 50% of the population.
- Based off the class data in this lab, the safe concentration for brine shrimp or lowest observable effect concentration is at the concentration of 0x and .1x. Only 10 brine shrimp died in those concentrations combined. This means this is the safest environment for shrimp to survive in.
- If one were to pursue this investigation further in order to publish one's results in a scientific journal, the improvements that would make this a better lab would to test other solutions on the shrimp because they are very hardy animals and possibly using another organism living in the same environment as the brine shrimp to see how that organism gets affected by the tea extract.
- Because the brine shrimp are tolerant to many pollutants, the Daphnia would be a better choice for being an indicator species in an environment. The Daphnia would be a better choice because the Daphnia would first tell the scientists that there is a high concentration of a certain pollutant that is killing organisms and second the Daphnia is more relatable to other organisms because they all are around the same tolerance to pollutants, while the brine shrimp would tolerate more pollutants.
- The difference between Lethal Concentration and Lethal Dose is that the lethal dose is where 50% of the population is killed in a certain time period, while Lethal Concentration is the required concentration to kill 50% of the population. This is important because if a toxicologist were to mix the two up, then it could cause unnecessary deaths. (OSH Answers Fact Sheets)
Citations:
OSH Answers Fact Sheets. (n.d.). Retrieved November 9, 2015, from http://www.ccohs.ca/oshanswers/chemicals/ld50.html
(n.d.). Retrieved November 9, 2015, from http://kerajaancandragmail.blogspot.com/feeds/posts/default?orderby=updated
Toxic Tea: Determining LC50 of Herbal Tea. (n.d.). Retrieved November 4, 2015.
(n.d.). Retrieved November 9, 2015, from http://kerajaancandragmail.blogspot.com/feeds/posts/default?orderby=updated
Toxic Tea: Determining LC50 of Herbal Tea. (n.d.). Retrieved November 4, 2015.