1. Abstract Method Discussion Background Results References
The Dose Makes the Poison:
Measuring Ecotoxicity Using Lettuce Seed Assay
Elizabeth Pellerin
University of New Hampshire
Abstract
Method
Discussion
Ecotoxicity refers to the potential biological, chemical or physical stressors that affect an ecosystems. The purpose of this study was
to compare the toxicity of methanol, ethanol and isopropanol to see if these alcohols effect the germination and root elongation of a lettuce seed assay. Methanol is very toxic to human beings but interestingly enough it’s the least toxic to the lettuce seeds.
Various alcohol concentrations were distributed among the petri dishes which contained 15 seeds each.
The germination and root elongation period was five days
After five days the root length and the amount of seeds germinated were counted and recorded.
Each petri dishes root length in centimeters was averaged and recorded in the results section.
The results showed that methanol was the least toxic alcohol to the lettuce seeds.
Although methanol is least toxic to plants it is the most toxic of the three alcohols to humans.
Methanol occurs naturally during the decomposition of different plant and animal life in our environment.
When methanol is released into the environment it quickly biodegrades.
How does Measuring Ecotoxicity Using a Lettuce Seed Assay Relate to Green Chemistry?
Design Less Hazardous Chemical Syntheses
"Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.“
Use Safer Solvents/Reaction Conditions
"The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used."
Background
Results
References
Ecotoxicity involves the effects of toxic chemicals on biological organisms, especially at the population, community, ecosystem level
Common assays are available for aquatic and terrestrial ecotoxicity.
This experiment introduced terrestrial ecotoxicity of different alternative starting materials commonly used for the preparation of biodiesel.
In this experiment lettuce seed assays were used to compare ecotoxicity of a variety of concentration of methanol, ethanol and isopropanol.
The reason lettuce seeds were used is because they have proven to be an easy and inexpensive means of testing the toxicity of certain of contaminants of concern in water and sediments, including heavy metals and some pesticides and other organic toxicants.
E. (1992, April). Methanol. Retrieved from 
Environmental Impact - METHANOL INSTITUTE. (n.d.). Retrieved November 09, 2016, from 
Levy, Irv (10/24/16). Professor at Gordon College. Phone interview. Kwon, S. Y.; Levy, I. J.; Levy, M. R.; Sargent, D. V.; Tshudy, D. J.; Weaver, M. A. (2008)The dose makes the poison: Measuring ecotoxicity using a lettuce seed assay, Chemistry, Gordon College. 12 Principles of Green Chemistry - American Chemical Society. (n.d.). Retrieved November 09, 2016,fromhttps://
Germination results in different experimental containers after five days
Alcohol
Petri dish
(control)
(0.06%)
(1.3%)
(2.5%)
(5%)
(10%)
Methanol 15 11 13 10
Ethanol
Isopropanol 12 4
Mean root elongation for
germinated seeds after five days
Alcohol
Petri dish
(control)
(0.06%)
(1.3%)
(2.5%)
(5%)
(10%)
Methanol
1.95cm
1.62cm
1.26cm
0.4cm
0cm
Ethanol
1.66cm
0.50cm
Isopropanol
1.92cm
1.20cm
1.05cm