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
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 plants and animals 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.” Methanol is naturally occurring and performs biodegradable traits if present in 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.” This reaction minimizes toxicity to human health and the environment because the isopropanol and ethanol are easily disposed.
How does measuring ecotoxicity using a lettuce seed assay relate to organic chemistry?
Bio-fuels-The alcohols used in this experiment are commonly used in the preparation of bio- diesel.
Measurement/Analysis-This experiment provides quantitative/qualitative data of the effects of varying concentrations has on lettuce seed assays.
Toxicology- Is the branch of science that studies nature, effects and detection of poisons. In this experiment the concentrations of alcohols used on the lettuce seeds were very poisonous at higher concentrations. Interestingly enough methanol was the least toxic to the lettuce seed assays.
Environmental Chemistry- Studies the biochemical effects that occur in nature. It’s important we understand what chemicals are toxic to the environment so we can make better environmental choices
Various alcohol concentrations were distributed among the petri dishes which contained 15 seeds each.
Each petri-dish was sealed with parafilm in an undisturbed area with no additional supplemental light at room temperature.
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 dish’s root length in centimeters was averaged and recorded.
Ecotoxicity refers to the potential biological, chemical or physical stressors that effect 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.
Experimental alcohol concentrations
Seeded petri-dishes covered with parafilm
Root length being measured
Background
Results
References
Germination results in different experimental containers after five days
Ecotoxicity involves the effects of toxic chemicals on biological organisms, especially at the population, community, ecosystem level
A common assay is an investigative procedure used in a lab to access qualitative or quantitative measures of functional activity of a target entity (analyte) in the experiment.
The assay typically aims to measure an intensive property of the analyte and expresses it in a relevant unit of measurement (for ex. the effects of concentration has in comparison to the control etc.)
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 in water and sediments, including heavy metals, pesticides and other organic toxicants.
E. (1992, April). Methanol. Retrieved from 
Environmental Impact - METHANOL INSTITUTE. (n.d.). Retrieved November 09, 2016, from  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.
Levy, Irv (10/24/16). Professor at Gordon College. Phone interview.
The American Heritage dictionary of the English language (4th ed., Ser. 4). (2006). Boston, MA: Houghton Mifflin 12 Principles of Green Chemistry - American Chemical Society. (n.d.). Retrieved November 09, 2016,fromhttps://
Alcohol
Petri dish
(control)
(0%)
(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%)
(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