The potential for exposure to aerosolized algal toxins during harmful algal blooms has not been well studied. A fundamental question about the longevity of algal toxins in the aerosol phase remains. In this study, the influence of environmental factors such as sunlight and atmospheric oxidants (e.g., ozone and OH radicals) on the lifetime of microcystin-LR (MC-LR), which is known to be the most toxic of the MCs produced by cyanobacteria, was investigated. A cyanobacterial culture aliquot (Microcystis aeruginosa and Dolichospermum sp.) spiked with MC-LR was nebulized into a large outdoor photochemical chamber and atmospherically aged in the presence and absence of sunlight or ozone. The concentrations of MC-LR in aerosol were measured using liquid chromatography/tandem mass spectrometry and the enzyme-linked immunosorbent assay (ELISA) for atmospheric aging of aerosols. With 61.5 nm³ m^–3 gaseous ozone, the second-order rate constant of ELISA-based MC-LR in M. aeruginosa aerosol was approximately (3.91 ± 0.17) × 10⁵ M^–1 s^–1 (54 min lifetime). Because of the involvement of OH radicals, the daytime degradation of MC-LR was significantly faster than that at night with the same amount of ozone in the chamber air. We conclude that under natural sunlight, MC-LR in cyanobacterial aerosols quickly decays through heterogeneous chemistry with atmospheric oxidants but can still impact neighboring communities.

中文翻译：

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蓝藻气溶胶中微囊藻毒素-LR的大气进展

有害藻华期间暴露于雾化藻毒素的潜力尚未得到很好的研究。关于在气溶胶相中藻毒素的寿命的基本问题仍然存在。在这项研究中，环境因素（例如阳光和大气氧化剂（例如，臭氧和OH自由基））对微囊藻毒素-LR（MC-LR）的寿命的影响，该毒素是蓝细菌产生的MC最具毒性的，进行了调查。蓝藻培养液等分试样（铜绿微囊藻和Dolichospermum将掺有MC-LR的溶液喷雾到一个大型室外光化学室中，并在有无阳光或臭氧的情况下进行大气老化。使用液相色谱/串联质谱法和酶联免疫吸附测定法（ELISA）测定气溶胶在大气中的老化，以测定气溶胶中MC-LR的浓度。在61.5 nm ³ m ^–3气态臭氧下，基于ELISA的MC-LR在铜绿假单胞菌气溶胶中的二级速率常数约为（3.91±0.17）×10 ⁵ M ^–1 s ^–1（终身54分钟）。由于OH自由基的参与，在室内空气中存在相同数量的臭氧的情况下，MC-LR的白天降解明显快于夜间。我们得出的结论是，在自然阳光下，蓝藻气溶胶中的MC-LR通过与大气氧化剂的异质化学迅速衰减，但仍会影响邻近社区。