TESTS EXPOLORING THE EFFECTIVENESS OF ELECTRON BEAM TREATMENT FOR BALLAST WATER MANAGEMENT

Abstract

This technical report presents findings from bench-scale tests evaluating the ability of electron beam treatment to inactivate aquatic organisms. This evaluation was the first attempt to assess the electron beam treatment as a potential treatment method for ballast water in the Laurentian Great Lakes. Researchers from the Lake Superior Research Institute (LSRI) of the University of Wisconsin-Superior (UWS) in Superior, Wisconsin, USA traveled to the Fermi National Accelerator Laboratory, hereafter Fermilab, to conduct the bench-scale evaluation in January 2022. The test apparatus is a stationary copper particle accelerator that supplies a radiation dose expected to cause mortality in standard test organisms. It has been previously demonstrated that electron beam treatment can cause direct damage by creating either single- or double-strand breaks in the DNA molecule beyond cell repair (Shehata, M.M.K. et al., 2011) or recovery (Lei, J. et al., 2020). All experimental exposures were conducted at Fermilab. The irradiation process was conducted by Fermilab staff in the Illinois Accelerator Research Center’s (IARC’s) Accelerator Applications Development and Demonstration (A2D2) machine. Doses ranged from 1 to 50 kGy. Dose effectiveness testing was completed in two water types using bacteria, algae, and zooplankton—Escherichia coli, Selenastrum capricornutum, Eucyclops spp., and Daphnia magna, respectively. The treatment caused complete mortality for E. coli in both water types at even the lowest dose employed. Eucyclops spp. and Daphnia magna also experienced complete mortality in both water types between 5 and 10 kGy. Selenastrum capricornutum was the most resistant to treatment effect in both water types, but did experience mortality at the highest doses. Algae examined a week after exposure for delayed mortality experienced high mortality rates at all doses.