Effects of Water Types on

Copper Sulfate’s Toxicity on Duckweed

Brian Crofoot

Mount Union College Department of Biology

April 20, 2010

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photographs, Copyright 2010 Brian Crofoot.

This work, excluding all photographs, is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/ .

Photographs used for Commentary, Research, and Non-Profit Educational uses.

Overview1. Background information

a. Copper Sulfate b. Duckweed c. Water types

2. Experimenta. Introductionb. Experimentalc. Resultsd. Conclusion

3. Questions & Answers

First things first

Copper SulfateWhat is Copper Sulfate?

A. It’s a fungicide and herbicideB. Copper as an element is essential for

plant lifeC. A substance with many uses

Source: Alibaba.com

Source: practicalphysics.org

Why Copper Sulfate?Why is copper sulfate used?How does it affect plants?

Its an oxidantIt targets the chloroplasts in plants

Why do we need to understand its toxic effects?To better understand how it affects fish, birds,

plants, and other organismsWe need to know if organisms exposed to it will

be affected by it

Why Duckweed?

What is Duckweed? A member of the Lemna genus A small and very common plant

Why is it used in ecotoxicological research? It can be used as a model organism

in toxicological research Easy to find and cultivate

Source: Bonniesplants

Source: Alberto Godoy

Water TypesNatural Water

From a natural environmentTreated Waste Water

Has lots of nutrientsTap Water

It is drinking water and I wanted to learn about how it affects copper sulfate’s toxicity on duckweed

Spring WaterTo redo a previous experiment

Results from a Previous Bioassay

00.1

110

100

0

5

10

15

20

25

30

35

Duckweed Mortality in Spring Water on Day 7

Concentration of Copper Sulfate (g/L)

Number of Deaths

Effectsof

Water Types on

Copper Sulfate’s Toxicity on Duckweed

HypothesesCopper sulfate is harmful to Duckweed if it is

placed in treated waste water, natural water, and tap water, and in spring water in concentrations of more than 1.0g/L.

Copper sulfate acts as a nutrient for Duckweed if it is placed in spring water of concentrations of no more than 1g/L CuSO4

Duckweed will survive the best if it is placed in treated waste water

Experiment

BioassayWhat is a Bioassay?

Its an experimental method used to study the effects of toxins on organisms

It is an EPA approved technique

Why is this type of experiment important?Its purpose is to study how chemicals affect

organisms

EcotoxicologyEcotoxicology

A field of biology that tries to understand how toxins and pollutants affect organisms and ecosystems.

Tries to find ways to help organisms cope with pollutants and toxins

Bioassays are just one tool used in ecotoxicology

ProcedureSummary

1. Acclimate Duckweed for 1 week

2. Amounts of copper sulfate and waters were measured

3. Solutions were mixed

4. 10 duckweed were placed into each beaker

• Bioassay techniques were followed

• Each beaker had 200mL of the specific water type

• Each beaker had a certain concentration of copper sulfate

Copper (II) Sulfate pentahydrate was used

EPA Guidelines were followed

4 water types-Natural Water from Deer Creek Reservoir-Spring Water-Tap Water-Treated Waste Water

Concentrations of Copper Sulfate0g/L (control groups)0.1g/L1.0g/L10g/L100g/L

Results

LC 50

Spring Water Tap WaterNatural Water

Treated Waste Water

Day 1 1 g/L CuSO4 100 g/L None None

Day 3 1g/L 1g/L 10 g/L 10 g/L

Day 5 1 g/L 1 g/L 1 g/L 1 g/L

Day 7 0.1 g/L 0.1 g/L 0.1 g/L 0.1 g/L

LC 50 Values

ANOVA Analysis

Day 1's 2 Way ANOVA Results

Source of Varience df F P-value

Concentration 4 76.23 0

Water Types 3 23.62 0Interaction of Water types and concentration 12 5.43 0

Results Summary Initial

All duckweed are green and alive Day 1

Many Duckweed died in the higher concentrations of 10g/L & 100g/L, while as they survived in the lower concentrations

Day 3 All water types had almost no deaths in the two lowest concentrations of 0.0g/L

& 0.1g/L All duckweed in the 100g/L had died in all water types

Day 5 All duckweed in the 10g/L solutions had died in all of the water types Started to notice something weird about the duckweed

Day 7 Generally more than half of the duckweed in the 0.1g/L had died in all of the

water types All duckweed in the 1g/L solutions had died in all water types

Results Summary All p-values are significant and are below

0.01 after an ANOVA analysis of the dataOnly 1 duckweed died out of all of the control

groupsLC50s increased as time passedDuckweed survived the best in treated waste

waterDuckweed fared the worst in Spring Water

ConclusionsThe types of water significantly affect

Duckweed’s survivability when exposed to copper sulfate

The concentration of copper sulfate significantly affects Duckweed

There is a relationship between the concentration of copper sulfate and Duckweed’s survival

There is a significant interaction between copper sulfate and water types on Duckweed’s mortality rate

Duckweed’s ResponsesDuckweed tries to combat copper sulfate by

using antioxidants and proteinsCopper sulfate affects duckweed by causing

oxidative stressIt affects duckweed’s chloroplasts

In the Future…Redo this experiment to get a bigger data setTry using other types of waterTry using another organismTry using another concentration of copper

sulfate

RecapCopper sulfate is a toxic chemicalDuckweed is a useful organism to study

toxins in aquatic environmentA bioassay is an EPA approved experimental

procedure

Did you know?Alliance’s water is obtained from Deer Creek

Reservoir.

Copper Sulfate is not very toxic to humans unless ingested or inhaled.

Waste Water Treatment in the US is regulated by the EPA and State governmentsThe government has set tough regulations on

the quality of the water we use everyday

Important ReferencesHopkin, Steve P., D.B. Peakall, R.M. Sibly, and

C. H. Walker. Principles of Ecotoxicology, Third Edition. 3 ed. Boca Raton: CRC, 2005. Print.

Razinger J, Dermastia M, Drinovec L, Drobne D, Zrimec A, Koce JD (2007): Antioxidative Responses of Duckweed (Lemna minor L.) to Short-Term Copper Exposure. Env Sci Pollut Res 14 (3) 194–20

Wu, Lin. Class Lecture. Introduction to Ecotoxicology. Mount Union College, Alliance, Ohio. 2009

Special ThanksAlliance Water Treatment Facility and its

employeesDr. Lin WuMount Union College

The EndAny Questions?