Toxicity of ozonated seawater to marine organisms

Abstract

Ballast water transport of nonindigenous species (NIS) is recognized as a significant contributor to biological invasions and a threat to coastal ecosystems. Recently, the use of ozone as an oxidant to eliminate NIS from ballast while ships are in transit has been considered. We determined the toxicity of ozone in artificial seawater (ASW) for five species of marine organisms in short-term (< or = 5 h) batch exposures. Larval topsmelt (Atherinops affinis) and juvenile sheepshead minnows (Cyprinodon variegatus) were the most sensitive to oxidant exposure, and the mysid shrimp (Americamysis bahia) was the most sensitive invertebrate. Conversely, benthic amphipods (Leptocheirus plumulosus and Rhepoxinius abronius) were the least sensitive of all species tested. Mortality from ozone exposure occurred quickly, with median lethal times ranging from 1 to 3 h for the most sensitive species, although additional mortality was observed 1 to 2 d following ozone exposure. Because ozone does not persist in seawater, toxicity likely resulted from bromide ion oxidation to bromine species (HOBr and OBr-), which persist as residual toxicants after at least 2 d of storage. Total residual oxidant (TRO; as Br2) formation resulting from ozone treatment was measured in ASW and four site-specific natural seawaters. The rate of TRO formation correlated with salinity, but dissolved organic carbon and total dissolved nitrogen did not affect TRO concentrations. Acute toxicity tests with each water over 48 h using mysid shrimp, topsmelt, and sheepshead minnows yielded results similar to those of batch exposure. Addition of sodium thiosulfate (Na2S2O3) to ozonated waters resulted in TRO elimination and survival of all organisms. Our results provide necessary information for the optimization of an efficacious ozone ballast water treatment system.

Recent Technologies for Ballast Water Treatment

“…A treatment method under consideration is ozonation, which is being proposed as options for the management of ballast water (Herwig et al, 2006;Jones et al, 2006;Oemcke and van Leeuwen, 2004;Perrins et al, 2006Perrins et al, a, 2006b. Ozone is potentially a convenient disinfectant for shipboard treatment of ballast water as no chemicals need to be stored on ships or made available at ports for ships to use.…”

“…According to some authors (Bai et al, 2004;Champ, 2002;Gavand et al, 2007;Gregg and Hallegraeff, 2007;Herwig et al, 2006;Holm et al, 2008;Jones et al, 2006;Perrins et al, 2006b;Smit et al, 2008;Tang et al, 2006a,b;Veldhuis et al, 2006) new future ballast water treatment technologies under development include: (i) mechanical processes/methods: filtration and separation; (ii) physical processes/methods: sterilization by ozone, ultra-violet light, pulsating strobe lights, pressure, ultrasonic's, electric currents, acoustics, heat treatment, mixing, cyclone or hydrotech-drum settling, etc. ; (iii) chemical processes/methods: biocides (menadione, glutaraldehyde, peroxyacetic acid), and advanced oxidants or oxidizing chemicals (ozone by-products as bromine, sodium hypochlorite, and related chlorine compounds, hydrogen peroxide), nitrogen, oxygen depletion, pH, flocculation, etc.…”

“…However, this generally is viewed as a "stop-gap" measure to reduce the risk of invasions, because it may not be adequate as a control strategy. Structural and safety risks exist when conducting BWE in bad weather and/or high seas, and the limited data available call into question the effectiveness of the procedure (Brickman and Smith, 2007;Jones et al, 2006).…”

“…The human-mediated transfer of harmful organisms via shipping, specifically via ballast water transport, leading to the loss of biodiversity, alteration of ecosystems, negative impacts on human health and in some regions economic loss, has raised considerable attention especially in the last decade (Barry et al, 2008;Bolch and Salas, 2007;Brickman and Smith, 2007;Burkholder et al, 2007;David and Perkovic, 2004;Doelle et al, 2007;Eames et al, 2008;Endresen et al, 2004;Flagella et al, 2007;Gavand et al, 2007;Gray et al, 2006;Herwig et al, 2006;Holm et al, 2008;Jones and Corona, 2008;Jones et al, 2006;McCollin et al, 2007a,b;McGee et al, 2006;Murphy et al, 2006;Murphy et al, 2008;Niimi, 2004;van Leeuwen, 2004, 2005;Perrins et al, 2006ab;Roberts and Tsamenyi, 2008;Sano et al, 2005;Smit et al, 2008;Tang et al, 2006ab;Veldhuis et al, 2006;Wright et al, 2007a,b). Aquatic bio-invasions that have caused major impact to the host ecosystem are presented in Table 1, which also provides an overview of some known cases, but there are hundreds of other invasions, which have been reported around the world (IMO, 2004).…”

Hematological and histological changes of black porgy Acanthopagrus schlegeli in ozonated recirculating systems

“…Cooper (2002) indicated that ozone toxicity closely corresponded to total residual oxidants (TRO) rather than residual ozone itself in toxicity tests with various marine microalgae, invertebrates, and vertebrates. Ozone toxicity in seawater is mostly referred to as a function of total residual oxidants rather than as ozone itself (Crecelius 1979;Jones et al 2006).…”