Study of effectiveness of UV irradiation of single-cellular organisms transported with ballast waters of ships

Abstract

The technology of seawater decontamination from single-celled organisms with the use of ultraviolet (UV) radiation was investigated to prevent the introduction of alien organisms into local aquatic ecosystems with ballast water (BW) of ships. Experiments were carried out on the effects of low-pressure (LPL) and medium-pressure (MPL) mercury arc lamps on single-celled green algae, halophilic alga Dunaliella terricola and euryhaline alga Asteromonas gracilis, and also on the salt-resistant bacterium Nocardia sp. Doses of UV irradiation were determined for a tenfold decrease in the number of mobile algal cells and colony-forming units of the bacterium. For the first time, differences in the degree of damage with irradiation of LPL and MPL were found by example of the phytoplankton representatives. It was found that, during MPL irradiation, in contrast to LPL, except the cross-linking of the nitrogenous bases of DNA, other mechanisms are involved in the inactivation of microorganisms.