Characterization of Atmospheric Processes of Brevetoxins in Sea Spray Aerosols from Red Tide Events

BTXs removals by modified clay during mitigation of Karenia brevis bloom: Insights from adsorption and transformation

Harmful algal blooms (HABs), especially those caused by toxic dinoflagellates, are spreading in marine ecosystems worldwide. Notably, the prevalence of Karenia brevis blooms and potent brevetoxins (BTXs) pose a serious risk to public health and marine ecosystems. Therefore, developing an environmentally friendly method to effectively control HABs and associated BTXs has been the focus of increasing attention. As a promising method, modified clay (MC) application could effectively control HABs. However, the environmental fate of BTXs during MC treatment has not been fully investigated. For the first time, this study revealed the effect and mechanism of BTX removal by MC from the perspective of adsorption and transformation. The results indicated that polyaluminium chloride-modified clay (PAC-MC, a typical kind of MC) performed well in the adsorption of BTX2 due to the elevated surface potential and more binding sites. The adsorption process was a spontaneous endothermic process that conformed to pseudo-second-order adsorption kinetics (k2 = 6.8 × 10-4, PAC-MC = 0.20 g L-1) and the Freundlich isotherm (Kf = 55.30, 20 °C). In addition, detailed product analysis using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) indicated that PAC-MC treatment effectively removed the BTX2 and BTX3, especially those in the particulate forms. Surprisingly, PAC-MC could promote the transformation of BTX2 to derivatives, including OR-BTX2, OR-BTX3, and OR-BTX-B5, which were proven to have lower cytotoxicity.

Acute Effects of Brevetoxin-3 Administered via Oral Gavage to Mice

Brevetoxins (BTXs) constitute a family of lipid-soluble toxic cyclic polyethers mainly produced by Karenia brevis, which is the main vector for a foodborne syndrome known as neurotoxic shellfish poisoning (NSP) in humans. To prevent health risks associated with the consumption of contaminated shellfish in France, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) recommended assessing the effects of BTXs via an acute oral toxicity study in rodents. Here, we investigated the effect of a single oral administration in both male and female mice with several doses of BTX-3 (100 to 1,500 µg kg-1 bw) during a 48 h observation period in order to provide toxicity data to be used as a starting point for establishing an acute oral reference dose (ARfD). We monitored biological parameters and observed symptomatology, revealing different effects of this toxin depending on the sex. Females were more sensitive than males to the impact of BTX-3 at the lowest doses on weight loss. For both males and females, BTX-3 induced a rapid, transient and dose-dependent decrease in body temperature, and a transient dose-dependent reduced muscle activity. Males were more sensitive to BTX-3 than females with more frequent observations of failures in the grip test, convulsive jaw movements, and tremors. BTX-3's impacts on symptomatology were rapid, appearing during the 2 h after administration, and were transient, disappearing 24 h after administration. The highest dose of BTX-3 administered in this study, 1,500 µg kg-1 bw, was more toxic to males, leading to the euthanasia of three out of five males only 4 h after administration. BTX-3 had no effect on water intake, and affected neither the plasma chemistry parameters nor the organs' weight. We identified potential points of departure that could be used to establish an ARfD (decrease in body weight, body temperature, and muscle activity).

A scoping review of waterborne and water-related disease in the Florida environment from 1999 to 2022

Florida's environments are suitable reservoirs for many disease-causing agents. Pathogens and toxins in Florida waterways have the potential to infect mosquito vectors, animals, and human hosts. Through a scoping review of the scientific literature published between 1999 and 2022, we examined the presence of water-related pathogens, toxins, and toxin-producers in the Florida environment and the potential risk factors for human exposure. Nineteen databases were searched using keywords relating to the waterborne, water-based toxins, and water-related vector-borne diseases which are reportable to the Florida Department of Health. Of the 10,439 results, 84 titles were included in the final qualitative analysis. The resulting titles included environmental samples of water, mosquitoes, algae, sand, soil/sediment, air, food, biofilm, and other media. Many of the waterborne, water-related vector-borne, and water-based toxins and toxin-producers of public health and veterinary importance from our search were found to be present in Florida environments. Interactions with Florida waterways can expose humans and animals to disease and toxins due to nearby human and/or animal activity, proximal animal or human waste, failing or inadequate water and/or sanitation, weather patterns, environmental events, and seasonality, contaminated food items, preference of agent for environmental media, high-risk populations, urban development and population movement, and unregulated and unsafe environmental activities. A One Health approach will be imperative to maintaining healthy waterways and shared environments throughout the state to protect the health of humans, animals, and our ecosystems.