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Diving and ROV
Published in Sukumar Laik, Offshore Petroleum Drilling and Production, 2018
Breathing extremely high partial pressures of oxygen can lead to a reaction known as oxygen toxicity. Experimental evidence indicates that divers may suffer from two different forms of oxygen toxicity. The first and most serious kind affects the central nervous system (CNS), causing convulsions similar to those brought about by an epileptic seizure. Total loss of muscle control occurs, and the diver suffering from the effects of CNS oxygen toxicity may become unconscious. These dangers eliminate the use of pure oxygen as a breathing medium below 50 ft in commercial operations.
Titanium dioxide nanoparticles: synthesis, characterisations and aquatic ecotoxicity effects
Published in Chemistry and Ecology, 2018
Amine Mezni, Samir Alghool, Badreddine Sellami, Nesrine Ben Saber, Tariq Altalhi
In order to protect themselves from the damaging effects of activated free radicals, various organisms can stimulate their antioxidant enzyme activities. Among the common antioxidant enzyme, SOD is considered as the vital first-line defense against oxygen toxicity [21]. SOD catalyses the dismutation of the superoxide anion (O2−) produced in peroxisomes and mitochondria [22]. In the present study, the effects of acute exposure to TiO2 NPs on the SOD activity of M. galloprovincialis were analysed in digestive glands and gills. The data indicated that the concentrations used in the treatments might be insufficient for the induction of SOD in digestive glands even at high concentrations. These observations can be explained by the modest level of oxidative stress caused by TiO2 at this concentration in these organs. In contrast, SOD activity in gills increased after exposing mussels to 100 mg/L of TiO2. This demonstrates that M. galloprovincialis has an increased oxidative defense capacity in its gills for the elimination of excess O2−. Other reports have suggested that TiO2 increased SOD at high concentrations and related this modification to the oxidative stress induced by ROS.
Long term bioassessment multiple stressors study in a residential California stream
Published in Journal of Environmental Science and Health, Part A, 2021
Lenwood W. Hall, William D. Killen, Ronald D. Anderson, Raymond W. Alden
The key result from this multiple year study is that physical habitat and not contaminants (pyrethroids or metals) is the most important stressor shaping benthic communities in Pleasant Grove Creek. Unfortunately, this key stressor shaping benthic communities in this waterbody is not listed as an impairing agent in the 303 d listing process as only low dissolved oxygen, toxicity and pyrethroids were identified as impairing constituents. The omission of physical habitat as a significant impairing agent in Pleasant Grove Creek is a flaw in the environmental regulatory system that is designed to identify impairment in waterbodies, determine stressors responsible for impairment and design regulatory actions that can eliminate stressors causing impairment.
Oxidative responses of macro-invertebrates in relation to environmental variables in rivers of East Kalimantan, Indonesia
Published in Chemistry and Ecology, 2020
Fatmawati Patang, Agoes Soegianto
SOD and CAT are the vital first-line defenses against oxidative damage oxygen toxicity. They are essential for the conversion of ROS to harmless metabolites [29]. The dismutation of O2−2 is scavenged to H2O2 and O2 by SOD, and H2O2 is decomposed to non-toxic H2O and O2 by CAT [29–33]. The higher levels of SOD and CAT in Chironominae and Gomphus in Karang Mumus River confirm that these animals able to decompose the high amount of ROS by producing high quantity of SOD and CAT as the antioxidant defense system. While Lestes showed indifferent levels of SOD and CAT both in more turbid and clearer rivers.