The Effectiveness of Bromine as a Method to Stop Microbial Invasions via Ballast Water

By: Sarah Chmielewski

Department of Biological Sciences, York College of Pennsylvania

Introduction:What is ballast water?• Water held within tanks that stabilize a ship during transit•The water is collected at the starting port, then released at the destination What is the potential impact of ballast water?•Ballast water can bring invasive species • The invasive species could take over because they could have no predators in their new environment•If the native and invasive species have similar diets, the invasive species may outcompete the native species •Methods to eradicate invasive species are very time consuming and expensive Current methods to limit the transport of organisms in ballast water and their downsides•Chlorination (Azanza 2001)

oToxic at very low levels / these toxins are released into the environment

•UV treatment (Azanza 2001)oExpensive

oNot effective unless solids are removed•Deoxygenation (Tamburri 2002)oExpensiveoRequires a minimum of 96 hours of being held•Filtration (Waite 2003)oVery slow Why use bromine?•Chlorine and bromine are very similar chemically•Ballast water tanks are located near the ship’s engines and the water is heated to 37 C. •Bromine is more stable at higher temperatures then chlorine (Rogby 2000)•Bromine can be detoxified by adding sodium thiosulfate (Na2S2O3)

Hypothesis:H1 Bromine will have a higher efficiency than chlorine at removing microbes in ballast water.H2 In the samples treated with both chemicals, the sodium thiosulfate will detoxify the bromine, and the treatments will show no differences from the control.Question:Q1 What was the lowest concentration of bromine that would remove microbes from ballast water?

Acknowledgements:

I’d like to thank Dr. Nolan for all her help and input throughout these many years.

Dr. Mathur for her help in making batches of saltwater agar.

My friends and family for being supportive during the extent of this project.

And everyone that has helped me along the way.

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Conclusion:•Bromine at 10 ppm and 30 ppm inhibits microbial growth just as well as chlorine does.•The sodium thiosulfate did not detoxify the bromine.•After examining the outcome of the three tests the concentration that was consistently effective was the bromine at 10 ppm. This concentration did the best job at inhibiting both bacterial growth and relative fluorescence, and maintained a healthy pH level

•Bromine seems to be a promising method for treating ballast water but more research is needed on the matter before anything definite can be said.

Literature cited:•Azanza, M.P.V., R.V. Azanza, A.I. Gedaria, H.G. Sententa, and M.V. Idjao. "Decimal Reduction Times of Pyrodium bahamense Var. compressum and Escherichia coli in Chlorine and Ultraviolet-Treated Seawater." The Society for Applied Microbiology 33 (2001): 371-376. •Rogby, Geoff. "From Ballast to Bouillabaisse." Science 289 (2000): 241. •Tamburri, Mario N., Kerstin Wasson, and Masayasu Matsuda. "Ballast Water Deoxygenation Can Prevent Aquatic Introductions While Reducing Ship Corrosion." Biological Conservation 103 (2002): 331-341. •Waite, T D., J Kazumi, P.v.z. Lane, L.l. Farmer, S.g. Smith, S.l. Smith, G. Hitchcock, and T.r. Capo. "Removal of Natural Populations of Marine Plankton by a Large-Scale Ballast Water Treatment System." Marine Ecology Progress Series 258 (2003): 51-63.

Results:•Bromine at a level of 10ppm when compared to chlorine is as effective at preventing bacterial growth•Sodium thiosulfate (Na2S2O3) addition did not significantly inhibit or facilitate growth when added.

•Bromine at both 10 ppm and 30 ppm is as effective as chlorine at reducing phytoplankton growth.•Na2S2O3 does not affect the concentration of phytoplankton.

•Bromines at levels 1 and 10 ppm and the controls all lower the pH to the same level•Chlorine at 10 ppm and bromine at 30 ppm lowered the pH a significantly different amount•Na2S2O3 had no effect on the raising or lowering of the pH

Figure 2. Relative fluorescence of the samples collected from Sandy Point State Park and treated with concentrations of either bromine, chlorine, or a combination of bromine and sodium thiosulfate. Mean +/- standard deviation. Statistical analysis was performed with 2 way ANOVA and a bonferroni post-test. Letters indicating significant differences

Figure 3. pH levels of the samples collected from Sandy Point State Park and treated with concentrations of either bromine, chlorine, or a combination of bromine and sodium thiosulfate. Mean +/- standard deviation. Statistical analysis was performed with 2 way ANOVA and a bonferroni post-test. Letters indicating significant differences

Figure 1. The number of bacteria colonies grown on salt water medium of the samples collected from Sandy Point State Park and treated with concentrations of either bromine, chlorine, or a combination of bromine and sodium thiosulfate. Mean +/- standard deviation. Statistical analysis was performed with 2 way ANOVA and a bonferroni post-test. Letters indicating significant differences

http://americancargoline.com/ship1.jpg

Future Research:•Testing the effects of bromine on larger organisms like zoo plankton, fish larvae and fish•Investigate other ways to detoxify bromine before it exits the ballast water tank