On a daily basis, aquatic ecosystem is exposed to heavy metals, drugs, and chemicals; the continuous exposure results in a toxic effect, depending on the dose and duration of exposure. Studies have confirmed tardigrade to be highly tolerant to very high temperature, pressure, gravity, etc. This study aimed at confirming various toxic damages caused by exposure to cadmium solution and the antioxidative effect of selenium in the amelioration of the effects. To model the environmental route of exposure, toxicants were added to tardigrade (H. exemplaris) culture done in deionized water to remove non-bioavailability of cadmium caused by culturing tardigrades in agar medium. As was observed in pure tardigrades, with no exposure to cadmium, there was no alteration in the metabolism of tardigrades. However, when solutions of cadmium were added to the tardigrade culture (at concentrations of 0.5 ppb, 1.0 ppb), increased sensitivity to oxidative stress as well as significantly reduced metabolism was observed. More specifically, after 6 h of exposure, the metabolism dropped relative to the control organism. The produced reactive oxygen species was confirmed with fluorescence microscopy. Finally, treating the exposed tardigrades with deionized water did not ameliorate the toxic effects of the cadmium to the tardigrades; instead, the effects were reduced, and this is due to water only diluting the toxicants. However, with 0.5 ppm of selenium, using sodium selenite counteracted the cadmium-induced reactive oxygen species produced over a 6-h period from the point of exposure through the exposure period. The antioxidative enzymes (catalase (CAT), superoxide dismutase (SOD), and acetylcholine (Ach)) produced were quantified using various assay methods. In conclusion, from an environmental perspective, selenium is a relevant antioxidant using the appropriate dosage.

水生生态系统每天都暴露于重金属，药物和化学物质中。连续暴露会产生毒性作用，具体取决于暴露的剂量和持续时间。研究已经证实了缓凝剂对非常高的温度，压力，重力等具有高度的耐受性。该研究旨在证实暴露于镉溶液引起的各种毒性损害以及硒在改善作用中的抗氧化作用。为了模拟暴露的环境途径，将有毒物质添加到缓凝剂中（H.示范。）在去离子水中进行培养，以去除由于在琼脂培养基中培养缓坡剂引起的镉的非生物利用度。如在纯净的兽脚类动物中所观察到的，没有暴露于镉的情况下，兽脚类动物的代谢没有改变。但是，将镉溶液添加到缓坡培养物中（浓度为0.5 ppb，1.0 ppb）时，观察到对氧化应激的敏感性增加，并且代谢明显降低。更具体地说，在暴露6小时后，新陈代谢相对于对照生物体下降。通过荧光显微镜确认产生的活性氧种类。最后，用去离子水处理暴露的缓坡生物并不能改善镉对缓坡的毒性作用。相反，效果降低了，这是因为水只会稀释有毒物质。但是，在硒含量为0.5 ppm的情况下，使用亚硒酸钠可以抵消从暴露到暴露期间6小时内产生的镉诱导的活性氧。使用各种测定方法对产生的抗氧化酶（过氧化氢酶（CAT），超氧化物歧化酶（SOD）和乙酰胆碱（Ach））进行定量。总之，从环境角度看，硒是使用适当剂量的一种相关抗氧化剂。使用各种测定方法对产生的乙酰胆碱和乙酰胆碱（Ach）进行定量。总之，从环境角度看，硒是使用适当剂量的一种相关抗氧化剂。使用各种测定方法对产生的乙酰胆碱和乙酰胆碱（Ach）进行定量。总之，从环境角度看，硒是使用适当剂量的一种相关抗氧化剂。