Experiment and Findings by Jordan Turner, Kayce Cook, and Lauren

LaganaHCOP PE 2008

The Effects of Rock Salt(Calcium Magnesium Acetate) on

Lumbriculus variegatus

Background of Chosen Solutions…

CMA, or Calcium magnesium acetate, is a form of rock salt used for deicing roads and highways. It affects the melting point of the ice, lowering it enough to melt in below-freezing weather.

The solution is extremely hypertonic, drawing water from animal cells to reach equilibrium.

Our chosen solutions for the pulsation test: Control (Spring Water), Group I (1% CMA and Spring Water solution), Group II ( 5% CMA and Spring Water solution).

HypothesesWe hypothesize that the CMA solution will

affect the L. variegatus ‘s pulsation rates by speeding them up because the solution is hypertonic, pulling water from the worms’ bodies and increasing their pulsation rate.

We hypothesize for the locomotion test that the CMA solution will decrease locomotion rate compared to the control group in spring water by drawing water from the worms into the hypertonic solution.

We hypothesize for the chemotatic test that L. variegatus will react to the CMA solution as a repellant, and will move away from it.

Pulsation Experimental Design

Control Group 1%

CMA

5% CMA

30 Worm

s

10 Worm

s10

Worms

10 Worm

s

Materials and Methods for Pulsation Test

• Control Group: 10 worms• 1% CMA Test Group: 10 worms• 5% CMA Test Group: 10 worms• Placed each test group in assigned solutions, allowing

the worms to be exposed for 10-15 minutes. Extracted the worms after allotted time period and measured their pulsation rates within 10 seconds, and multiplied by 6 to get pulsations per minute.

• Statistical analysis was performed using ANOVA (JMP v. 7 SAS). Model effect tested was treatment. Mean comparisons were determined using Student’s t-Test. Data are reported as means ± standard deviations.

• Calculated mean and standard deviation.

Locomotion Experimental Design

30 Worms

Control Group

0.5% CM A

1% CMA

10 Worms

10

Worms

10 Worm

s

Materials and Methods for Locomotion Test

Control Group: 10 worms0.5% CMA Test Group: 10 worms 1% CMA Test Group: 10 wormsPlace each group of worms into assigned

solutions, exposing them for 10-15 minutes.Build the track to measure the distance traveled

by each worm, marking in centimeters. Extracting the worms, place one by one into the track, measuring the distance for 30 seconds. Multiply by 2 to get distance traveled per minute.

We calculated the mean, standard deviation.

Chemotatic Experimental Design

30 Worms

Control Group

0.5% CM A

1% CMA

10 Worms

10 Worm

s

10 Worm

s

Materials and Methods for Chemotatic Test

Control Group: 10 worms0.5% CMA Test Group: 10 worms1% CMA Test Group: 10 wormsSeparating the test worms, place each

worm into a petri dish and apply one drop of the assigned solution to its tail, monitoring behavior for 30 seconds. Results depend on a positive response (moving back towards its tail) or a negative response (moving away from its tail) to the differing solutions.

Response to CMA solutions

02468

1012

Control 0.5%CMA

1% CMA

treatment groups

Num

ber o

f wor

ms

Positive

Negative

Chemotatic Test Chart

Summary of Results and Conclusions

Pulsation rates increased with the addition of 1% CMA solution. This supported our hypothesis. However, we also discovered that 5% CMA solution was too concentrated for our worms, resulting in death. We decided to create a weaker solution of 3% CMA.

There was a significant difference in the mean distances traveled by our two test groups. The group with 1% CMA solution traveled less distance, supporting our hypothesis. However, 3%CMA solution also caused death. We created a final solution of 0.5% CMA.

We hypothesized that the worms would be repelled by the CMA solution. For both CMA concentrations (0.5% and 1%), 70% of the worms reacted positively by moving toward the solution.

DiscussionAlthough we routinely use rock salt as a de-

icing agent on roadways and highways for safer travel, it was found to be lethal to California black worms at high concentrations. Harm to invertebrates could become evident on roadways near streams and rivers. In the laboratory, CMA was found to alter their physiology. By adding CMA to roadways, we are adding additional salt to the environment which could pose a risk to freshwater organisms.

Sources and CitationsSardo, Soares, Gerhardt. “Behavior, Growth, and

Reproduction of Lumbriculus Variegatus (Oligochaetae) in Different Sediment Types”. Human and Ecological Rich Assessment, 13:519-526, 2007.

http://www.informaworld.com/smpp/content~content=a778588780~db=all~order=page

Cushman, J.R.; Duff, V.A.; Butfau, G.H.;Aust, L.B.; Caldwell, N.; Lazer, W.. “Evaluation of CMA and Road Salt for Contact Hypersensitivity Potential and Dermal Irritancy in Humans”. Contact Dermatitis (01051873) Apr91, Vol. 24, Issue 4, p.289-292

http://www.ncbi.nlm.nih.gov/pubmed/1831107

Sources and Citations Continued

McFarland, B.L.; O’Reilly, K.T.. “Environmental Impact and Toxicological Characteristics of Calcium Magnesium Acetate”. Chemical Deicers and the Environment. Lewis Publishers, Boca Raton, Florida.1992. p 192-227. 9 fig, 6 tab, 50 ref.

http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=9306831