The Lethality of Hot Water and Ozone on Aquatic Invasive Species: Data

The spread of Aquatic Invasive Species (AIS) between the Great Lakes and Mississippi River Basin by way of the Chicago Area Waterway System (CAWS) is a pressing concern to resource managers in the Midwest region. Augmenting this spread are watercrafts traveling though the CAWS locks and dams. AIS are able to attach to boat hulls, equipment, or are present in the surrounding water during lock transfers. It has been proposed that chemically treating boats during lock transfers would be an effective way to reduce the spread of AIS. Of a range of treatments identified as candidates to do this, hot water and dissolved ozone ranked high as effective treatments causing the least amount of environmental impact. This study assessed the lethality of hot water and dissolved ozone, separately and in combination, on select AIS in a laboratory setting. Species were exposed to water temperatures ranging from 18 to 50°C, ozone concentrations ranging from 0 to 920 ORP (Oxidation-Reduction Potential), and exposure durations ranging from 10 to 60 min to find treatments capable of inducing 100% mortality. Results indicated that water at 45°C achieved 100% mortality in all species tested with a 10 min exposure. Ozone concentrations induced significant mortality to all species tested, particularly when combined with elevated temperatures.水生入侵物种（Aquatic Invasive Species, AIS）通过芝加哥地区航道系统（CAWS）在五大湖与密西西比河流域之间的传播，是美国中西部地区资源管理者面临的紧迫议题。往来于CAWS船闸与大坝的船舶进一步加剧了这一传播态势：AIS可附着于船体、船舶设备之上，或在船闸过闸过程中留存于周边水域内。有研究提出，在船闸过闸阶段对船舶进行消杀处理，是降低AIS传播风险的有效手段。在经筛选的候选消杀方案中，热水与溶解臭氧因消杀效果显著且环境影响极小，位列优选方案之列。本研究在实验室环境下，分别测试了热水、溶解臭氧及其组合方案对选定AIS的致死效果：受试物种分别暴露于18至50℃的水温、0至920 ORP（氧化还原电位, Oxidation-Reduction Potential）的臭氧浓度环境中，暴露时长覆盖10至60分钟，以筛选可实现100%致死率的处理方案。实验结果显示，水温45℃、暴露10分钟即可对所有受试物种实现100%致死率；特定臭氧浓度即可对所有受试物种造成显著致死效果，尤其当与高温环境联用时效果更为突出。