The varying concentrations of polycyclic aromatic hydrocarbons (PAHs) at remote islands is an important indicator, demonstrating the contributions from different regional combustion sources. In this study, gaseous and particulate PAHs were measured at Weizhou Island in the Gulf of Tonkin from 15th March to 14th April, 2015. The concentrations of PAHs ranged from 116.22 to 186.74 ng/m³ and from 40.19 to 61.86 ng/m³ in gas and particulate phase, respectively, which were much higher than those of some remote sites in Asia. Phenanthrene, fluoranthene, pyrene, and chrysene, which were mainly found in diesel vehicle emissions, had relatively high concentrations in both gas and particulate phases. According to the comprehensive results of back trajectory cluster analysis and diagnostic ratios, the local vessel emission was probably the main source of PAHs, which was much more important than the coal and biomass combustion sources from remoter regions. The toxicities represented by ∑PAH₇, benzo(a)pyrene-equivalent carcinogenic power, and 2,3,7,8-tetrachlorodibenzo-p-dioxin-based total toxicity potency are much higher in particulate phase than those in gas phase. However, the toxicities of gas phase should not be neglected from the point of view of indirect-acting mutagenicities due to the high contribution of fluoranthene.

Sonosensitizers play a crucial role in the efficacy of sonodynamic antitumor therapy (SDT) and sonodynamic antimicrobial chemotherapy (SACT), highlighting the necessity for the development of new compounds with good sonodynamic activity. In this study, three novel 3-substituted ciprofloxacin derivatives (CIPD1, CIPD2, and CIPD3) were designed and synthesized. Their sonodynamic activities were evaluated by assessing the damage to bovine serum albumin (BSA) and Escherichia coli (E. coli). Furthermore, the potential mechanism underlying their sonodynamic damage activities was investigated by detecting reactive oxygen species (ROS) under ultrasound irradiation (US). The results demonstrated that all three derivatives exhibited enhanced sonodynamic damage to BSA and E. coli under US, with CIPD1 and CIPD2 showing superior effectiveness compared to CIP. Both the concentrations of derivatives and the duration of ultrasound irradiation were found to significantly impact their sonodynamic effects. All three CIP derivates could be activated to produce ROS following ultrasound irradiation, primarily consisting of ¹O₂ and ·OH. The levels of ROS production were positively correlated with their sonodynamic activities, potentially explaining the mechanism underlying their sonodynamic damage activities.