Characterization of Red Tide Aerosols

佛罗里达赤潮是由甲藻凯伦/a brevis产生的，几乎每年都发生， 对经济和健康的不利影响。人暴露于含有雾化钾的海水喷雾中。短原因 对眼睛、鼻子和喉咙的刺激，以及某些个体的支气管收缩。前5年 在该计划的项目中，我们已经开发了表征赤潮气溶胶和评估个人健康状况的方法。 exposure.我们已经获得了关于K.在海滩上的brevis， 暴露和非暴露期间的粒度分布。我们已经制定了剂量估计 研究显示，空气中的短尾藻毒素与所观察到的 呼吸影响。 我们还表明，PbTx是由波能发电产生的海洋气溶胶的一个组成部分。 气泡机制在红潮发生期间，PbTx气溶胶的浓度通常低于100 ng/m3，足以增加职业接触中人类受试者的呼吸道症状 研究和研究涉及哮喘患者中所描述的项目由火焰。测得的红潮 气溶胶颗粒大小为粗颗粒模式（直径>1 μ m），空气动力学质量中值 直径在6至9.6 μ m之间。根据测量的颗粒大小进行的剂量估计显示， 在人呼吸道中的沉积分数为82%至89%。大部分吸入的红潮气溶胶 沉积在上呼吸道（鼻、口、咽和喉区域），沉积量较小但并非不显著 （3 - 7%）在下气道。吸入的赤潮气溶胶在呼吸道中沉积效率高， 呼吸道和沉积模式将有助于解释观察到的呼吸道症状。我们的剂量 估计表明，在人类呼吸道的某个区域中沉积的几ng PbTx可能是 与上呼吸道和/或下呼吸道系统中观察到的症状相关。我们的剂量估计显示 暴露于低至3至5 ng/m3空气浓度可能足以与上呼吸道相关 可能需要30-40 ng/m3的较高PbTx浓度才能引起下呼吸道症状 治疗哮喘它还表明，短杆菌毒素是与人类相关的最有效的物质之一， 呼吸影响。 我们在毒素探针和分析的同事继续从K中分离和鉴定化合物。brevis 具有与短吻蝮蛇毒素相关的结构的培养物。这些包括新的短尾毒素（PbTx-11，12）， Brevenals（呼吸作用拮抗剂）。随着这些新化合物的鉴定，我们还需要 并从实地研究所得的红潮气溶胶样本中量化。此外，我们的研究结果表明， 在采样周期内，PbTx曲线随环境条件变化而发生变化。因此会 有助于改善对个人暴露和上呼吸道局部沉积模式的评估， 将观察到的呼吸道症状与个人接触联系起来。 基于这些新的资料，我们建议继续研究，以进一步表征赤潮气溶胶 并探讨预测及减低红潮气溶胶暴露量的方法。我们的总体目标 建议的研究包括：（1）鉴定可能影响呼吸系统健康的红潮气溶胶成分 影响，包括PbTxs、拮抗剂和同系物，（2）改善个人暴露评估， 暴露的生物标志物，（3）提高对海洋气溶胶形成和传输的认识 （4）建立一个赤潮气溶胶模式。从以下来源获得的信息： 这些研究有助评估人体吸入红潮气溶胶的风险，并提供 预测赤潮气溶胶事件的方法，这可能有助于减少未来对赤潮气溶胶的暴露。

The Florida red tide, produced by the dinoflagellate Karen/a brevis, occurs almost annually and has adverse economic and health effects. Exposure of people to sea spray containing aerosolized K. brevis causes irritation of the eyes, nose, and throat, as well as bronchoconstriction in some individuals. In the first 5 years of the program project, we have developed methods to characterize red tide aerosol and to assess personal exposure. We have obtained information on the brevetoxin level produced by K. brevis on the beach and particle size distribution during exposure and non-exposure periods. We have developed dose estimates of the inhaled red tide aerosol and have showed an association of airborne brevetoxins to the observed respiratory effects. We also have shown that PbTx is a component of the marine aerosol generated from a wave-powered bubble mechanism. The concentration of PbTx aerosol during the red tide episodes is usually below 100 ng/m3, which is sufficient to increase respiratory symptoms in human subjects in an occupational exposure study and studies involving asthma patients as described in the the Project by Flaming. The measured red tide aerosol particle size is in the coarse particle mode (>1 mu m in diameter) with a mass median aerodynamic diameter between 6 to 9.6 (mu m. The dose estimate based on the measured particle size showed a total deposition fraction of 82 to 89% in the human respiratory tract. The majority of inhaled red tide aerosol deposited in the upper airway (nasal, oral, pharynx and larynx region) with small but not insignificant deposition (3 to 7%) in the lower airways. The inhaled red tide aerosol has high deposition efficiency in the respiratory tract and the pattern of deposition would help to explain the observed respiratory symptoms. Our dose estimate indicates that several ng of deposited PbTx in a certain region of the human respiratory tract could be associated with observed symptoms in upper airway and/or lower airway systems. Our dose estimate shows that exposure to air concentrations as low as 3 to 5 ng/m3 may be sufficient to relate to upper airway symptoms, and higher PbTx concentrations of 30-40 ng/m3 may be required to cause lower airway symptoms for asthmatics. It also shows that brevetoxin is one of the most potent substances associated with human respiratory effects. Our colleagues at the Toxin Probes and Assays continue to separate and identify compounds from K. brevis cultures with structures related to the brevetoxin. These include the new brevetoxins (PbTx-11,12), and brevenals (antagonists of respiratory effects). As these new compounds are identified, we also need to quantify them in red tide aerosol samples obtained in the field study. In addition, our results show temporal variation of the PbTx profile during the sampling period as environmental conditions change. Therefore, it will be useful to improve the assessment of personal exposure and local deposition pattern in the upper airway to relate the observed respiratory symptoms with individual exposure. Based on this new information, we propose to continue studies to further characterize red tide aerosol and to investigate the means to predict and minimize red tide aerosol exposure. The overall objectives of our proposed study are (1) to identify red tide aerosol components that may have implications for respiratory heath effects including PbTxs, antagonists, and congeners, (2) to improve assessment of personal exposure and biomarkers for exposure, (3) to improve the understanding of marine aerosol formation and transport processes, and (4) to develop a model of the red tide aerosol in the affected area. Information gained from these studies will aid in evaluation of human risk associated with inhalation of red tide aerosols, and provide a means to predict red tide aerosol events, which may help to minimize future exposures to red tide aerosol.