The Effects of Roundup® on Eisenia fetida

1. The Effects of Roundup® on Eisenia fetida Nathan Brownrigg Senior Capstone Spring 2005

2. Topics to be Discussed • Background Information • Materials and Methods • Results • Discussion of Results • Questions

3. Background Information • Roundup® is a common herbicide. • Glyphosate is the active chemical. It is also used in many other herbicides. • Ingredients: Glyphosate 18%, Diquat Dibromide 0.73%, Others 81.27%.

4. Background Information • Generally used to kill weeds and grasses. Tree stumps can also be killed by drilling holes into a fresh stump and applying the concentrated herbicide into the holes. • The herbicide is applied to the foliage of the plant and it systemically moves to the roots. • The chemical works by preventing the plant from producing certain amino acids. • This inhibits protein synthesis in the plant and eventually kills it.

5. Background Information • Glyphosate is generally not active in the soil (it is applied to foliage). • Strongly absorbed by the soil. • Half-life can range from 3-130 days. • Eventually broken down by soil microorganisms. • Effects on soil invertebrates not known.

6. Background Information • Eisenia fetida • Known as redworms. • Very important compost organism. • Commonly bred for use in compost heaps.

7. Background information • Earthworms in general are important soil invertebrates. Their burrowing and feeding activities enhance soil fertility by incorporating thatch throughout the soil. • Because so much soil passes through their bodies and they are in constant contact with the soil, there is a significant possibility of toxins becoming concentrated within them.

8. Background Information • Because of possible toxin build up, earthworms can be used as bioindicators of pollution in the soil.

9. Topics to be Discussed • Background Information • Materials and Methods • Results • Discussion of Results • Questions

10. Materials and Methods • Roundup® superconcentrate was obtained from local lawn and garden center. • Enough to treat 3,000 sq ft. (using recommended amount).

11. Materials and Methods • Containers were prepared by adding approximately 1,000 grams of soil. • Soil depth was about 3 cm, which was recommended by the Carolina Biological Supply Co.

12. Materials and Methods • In all, 12 containers were prepared this way. • One other container was filled with a little more soil to maintain the earthworms not to be used in the experiment.

13. Materials and Methods • Earthworms were then counted into groups of 50 and weighed using an electronic balance and placed in one of the 12 containers. • These numbers later serve as the initial biomass of the earthworms.

14. Materials and Methods • The recommended concentration for Roundup®: • 6.0 fl oz. per gallon of water. • Converted for experimental use; the recommended concentration: • 14.1 ml Roundup® per 300 ml solution (distilled H2O + herbicide.) (4.7%)

15. Materials and Methods • Concentrations were then determined for experimental use: • Control: 0.00 (distilled H2O) • Experimental groups: 7.05(2.4%), 14.1(4.7%), 28.2(9.4%), 42.3(14.1%), and 70.5(23.5%) ml Roundup® per 300 ml solution.

16. Materials and Methods • The concentrations were applied to each container. • One concentration per container, 6 concentrations, 12 containers = two experiments running concurrently.

17. Materials and Methods • The containers were then left to incubate for 30 days. • Day 14: Moist corn meal was applied to the soil for food (as instructed by Carolina Biological Supply Co. manual).

18. Materials and Methods • Worms removed and reweighed after 30 days. • Weight was compared to original biomass. • Number of dead worms was also recorded.

19. Topics to be Discussed • Background Information • Materials and Methods • Results • Discussion of Results • Questions

20. Results • Too many earthworms from trial 1 died to collect data. • Due to dehydration (no mortality was observed in other three trials). • The following tables and graphs show the results from trials 2-4.

21. Results

23. Results

25. Results

28. Topics to be Discussed • Background Information • Materials and Methods • Results • Discussion of Results • Questions

29. Discussion of Results • These numbers indicate that Roundup® has a negative effect on the biomass of Eisenia fetida. However, the herbicide is not fatal to the earthworms at these concentrations.

30. Discussion of Results • Concentrations above the recommended did not consistently decrease the biomass of the earthworms. • Experimental error may have had an effect on trial 2. However, this was corrected and results of trials 3 and 4 were relatively consistent.

31. Questions????????

32. References • Bauer C., Rombke J. 1996. Factors influencing the toxicity of two pesticides on three lumbricid species in laboratory tests. Soil Biol. Biochem. 29, 705-708. • Callahan C.A. 1984. Earthworms as ecotoxicological assessment tools. United States Environmental Protection Agency, EPA-600/D-48-272. • Mosleh Y.Y., Paris-Palacios S., Couderchet M., Vernet G. 2003. Acute and sublethal effects of two insecticides on earthworm (Lumbricus terrestris L.) under laboratory conditions. Environ. Toxicol. 18(1), 1-8. • Mosleh Y.Y., Paris-Palacios S., Couderchet M., Vernet G. 2002. Effects of the herbicide isoproturon on survival, growth rate, and protein content of mature earthworms (Lumbricus terrestris L.) and its fate in the soil. Applied Soil Ecology 23, 69-77. • Pendergrass W. 1980. Carolina Protozoa and Invertebrates Manual. Carolina Biological Supply Company. Burlington, NC. 34

33. Acknowledgements • Dr. McShaffrey • Dr. Pate