Jang Myoseon, Vuong Quang Tran, Madhu Azad, Kim Ganghan
PO Box 116450, Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, 32611, USA.
PO Box 116450, Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, 32611, USA.
Environ Pollut. 2025 Aug 6;384:126959. doi: 10.1016/j.envpol.2025.126959.
Harmful algal blooms (HABs) in lakes and estuaries, caused by cyanobacteria, pose various threats to humans and the environment. Cyanobacteria produce microcystins (MCs) that make animals and people sick. Once airborne, cyanobacterial aerosols are rapidly transformed through heterogeneous reactions with atmospheric oxidants, which tend to occur much faster in air than in water. The important aspects of these transformations include the degradation of MCs and the production of reactive oxygen species (ROS) from oxidized organic matter (OM) in cyanobacterial aerosol. In this study, MCs in aerosols and water samples, collected in lakes (Lake Okeechobee, Georges Lake, and Doctors Lake) of Florida during HABs, were measured using enzyme-linked immunosorbent assay kits. Organic hydroperoxides (OHP) and the oxidative potential (OP) associated with aerosols collected at Doctors Lake were measured with 4-nitrophenylboronic acid and dithiothreitol assays, respectively. The decay of MCs and the evolution of ROS in cyanobacterial aerosols were also demonstrated in an outdoor chamber under ambient sunlight. MC concentrations (0.4-2.1 μg/L) during HAB periods were higher than the US EPA guideline (0.3 μg/L for pre-school age and 1.6 μg/L for school-age and above). Airborne MC concentrations ranged from 0.2 to 5.7 ng/m. Regulations for airborne MC concentrations are yet to be established. In both field and chamber data, MCs decomposed but ROS substantially increased as aerosols atmospherically oxidized. Aerosolized OM concentrations during HABs were higher than those in dormant periods. OM in cyanobacterial aerosols was enriched at estuary Doctors Lake with high inorganic salt concentrations due to salting-out of water-soluble organics into lake-surface layers. Aerosolized OM concentrations were positively corelated to OP and OHP (r = 0.96 and 0.85, respectively) at Doctors Lake suggesting that cyanobacterial aerosols might adversely influence respiratory health. The longitudinal health impacts of aerosolized cyanobacteria emitted from HABs should be investigated in the future.
由蓝藻引起的湖泊和河口有害藻华（HABs）对人类和环境构成了各种威胁。蓝藻产生的微囊藻毒素（MCs）会使动物和人生病。一旦进入空气中，蓝藻气溶胶会通过与大气氧化剂的非均相反应迅速转化，这种反应在空气中往往比在水中发生得更快。这些转化的重要方面包括微囊藻毒素的降解以及蓝藻气溶胶中氧化有机物（OM）产生活性氧（ROS）。在本研究中，使用酶联免疫吸附测定试剂盒对佛罗里达州湖泊（奥基乔比湖、乔治斯湖和多ctors湖）在藻华期间采集的气溶胶和水样中的微囊藻毒素进行了测量。分别使用4-硝基苯硼酸和二硫苏糖醇测定法测量了多ctors湖采集的气溶胶中的有机氢过氧化物（OHP）和氧化电位（OP）。在室外环境阳光下的试验箱中也证明了蓝藻气溶胶中微囊藻毒素的衰减和活性氧的演变。藻华期间的微囊藻毒素浓度（0.4 - 2.1μg/L）高于美国环境保护局的指导标准（学龄前儿童为0.3μg/L，学龄及以上为1.6μg/L）。空气中的微囊藻毒素浓度范围为0.2至5.7 ng/m。空气中微囊藻毒素浓度的相关规定尚未制定。在野外和试验箱数据中，随着气溶胶在大气中氧化，微囊藻毒素分解，但活性氧大幅增加。藻华期间气溶胶化的有机物质浓度高于休眠期。由于水溶性有机物在湖面层盐析，河口多ctors湖蓝藻气溶胶中的有机物质在高无机盐浓度下富集。在多ctors湖，气溶胶化的有机物质浓度与氧化电位和有机氢过氧化物呈正相关（r分别为0.96和0.85），这表明蓝藻气溶胶可能对呼吸健康产生不利影响。未来应研究藻华排放的气溶胶化蓝藻对健康的长期影响。
