Exposure and Effect Assessment of Aerosolized Red Tide Toxins (Brevetoxins) and Asthma

Introduction: In previous studies, we demonstrated statistically significant changes in reported symptoms for life guards, general beach goers, and asthmatics, as well as statistically significant changes in pulmonary function tests in asthmatics, after exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols. In this study, we explored the use of different methods of intensive ambient and personal air monitoring to characterize these exposures to predict self-reported health effects in our asthmatic study population.

Methods: 87 asthmatic subjects with health effects measurements before and after 1 hour of exposure to Florida red tide aerosols were assessed for aerosolized brevetoxin exposure using personal and ambient samplers.

Results: After only 1 hour of exposure to brevetoxins in Florida red tide aerosols, asthmatics had statistically significant increases in self-reported respiratory symptoms and total symptom scores following exposure to aerosols containing brevetoxin concentrations above 57 ng/m3. However, we did not see the expected corresponding changes in pulmonary function test results. Significant increases in self-reported symptoms were also observed for those not using medication and those living > 1 mile from the coast.

Conclusions: These results provide additional evidence of health effects in asthmatics from ambient exposure to aerosols containing very low concentrations of brevetoxins, possibly the lower threshold for inducing a biologic response (i.e., toxicity). Consistent with the literature describing self-reported symptoms as an accurate measure of asthmatic distress, our results suggest that self-reported symptoms are a valuable measure of the extent of health effects from exposure to aerosolized brevetoxins in asthmatic populations.