The precautionary principle in public health emergency regime: Ethical and legal examinations of Vietnamese and global response to COVID-19.

Responses to the COVID-19 pandemic have been widely criticized for being too delayed and indecisive. As a result, the precautionary principle has been endorsed, applauded, and proposed to guide future responses to global public health emergencies. Drawing from controversial issues in response to COVID-19, especially in Vietnam, this paper critically discusses some key ethical and legal issues of employing the precautionary principle in public health emergencies. Engaging with discussions concerning this principle, especially in environmental law where the precautionary principle first appeared as a guiding principle with objective content(s), this paper formulates the precautionary principle as 'in dubio pro salus', which is about advising, justifying and demanding states to proactively prepare for scenarios arising out of any public health emergency. It distinguishes the precautionary principle into moderate and hard versions. A moderate version largely takes a holistic approach and fulfils a series of criteria specified in this paper, while a hard version either permits restrictive measures to be deployed primarily on a hypothetic basis or expresses an instrumental mentality. The hard version should be rejected because of the ethical and legal problems it raises, including risk-risk tradeoffs, internal paradoxes, unjustified causing of fear and unreasonable presupposition. Ultimately, this paper defends the moderate version.

Monitoring sublethal changes in fish physiology following exposure to a light, unweathered crude oil.

Biomarkers are frequently used to determine the exposure of fish to petroleum hydrocarbons following an oil spill. These biomarkers must be chosen carefully if they are to be used to determine sublethal toxic impacts as well as oil exposure. Many commonly used biomarkers relate to the metabolism of high molecular weight, typically pyrogenic, polycyclic aromatic hydrocarbons (PAHs), which are not abundant in unweathered crude oil. The goal of this study was to compare the efficacy of different biomarkers, including histological examination and transcriptomic profiling, in showing exposure to oil and the potential for sublethal toxic impacts. To achieve these goals, subadults/adults of the spotted dragonet (Repomucenus calcaratus) were exposed to a representative light, unweathered Australian oil for 96 h, so that the physiological changes that occur with exposure could be documented. Fish were then transferred to clean sediment for 90 h to quantify recovery. Biomarker changes, including PAH metabolites, 7-ethoxyresorufin O-deethylase (EROD), and histopathology, are presented in this work. In addition, a de novo transcriptome for the spotted dragonet was assembled, and differential transcript abundance was determined for the gill and liver of petroleum-exposed fish relative to a control. Increased levels of some biliary phenanthrene metabolites were seen throughout the exposure period. EROD levels showed modest, but not significant, increases. Transcriptomic differences were noted in the abundances of transcripts with a role in inflammation, primary metabolism and cardiac function. The patterns of transcript abundance in the gill and the liver changed in a manner that reflected exposure and recovery. The histology showed elevated prevalence of lesions, most notably vacuolization in liver and heart tissue, multi-organ necrosis, and lamellar epithelial lifting and telangiectasia in the gill. These findings suggest that short-term exposures to low molecular weight PAHs could elicit changes in the health of fish that are well predicted by the transcriptome. Furthermore, when light oil is released into the environment, exposure and subsequent risk would be better estimated using phenanthrene metabolite levels rather than EROD. This study also adds to the weight of evidence that exposure to low molecular weight PAHs may cause cardiac problems in fish. Further study is needed to determine the impact of these changes on reproductive capacity, long-term survival, and other population specific parameters.