Current status and recommendations toward a virus standard for ballast water

Abstract

Ballast water contains and transfers a variety of biological and non-biological materials between biomes. This study aimed to summarize published literature on the viruses found in ballast water, to evaluate ultrafiltration and plaque assay as methods for concentrating and enumerating viruses, and to assess the efficacy of UV irradiation in the inactivation of infectious viruses in ballast water. Previous studies reported high virus concentrations in ballast tanks, ranging from 109 to 1014 viral particles/L. The ultrafiltration and plaque assay were efficient in concentrating and enumerating four types of phages: MS2, PhiX174, P22, and PP7. The UV dose (radiant fluence) necessary to achieve a 4-log reduction of the four phages ranged from 6.1 to 77.7 mJ/cm2 with MS2 being the most UV-resistant phage. The results illustrated the applicability of ultrafiltration and plaque assay techniques for quantifying viruses in ballast waters and pointed to the need for additional test microorganisms for assessing ballast water quality.