Marine aerosol as a possible source for endotoxins in coastal areas Naama Lang-Yona a , Yoav Lehahn a , Barak Herut b , Noa Burshtein a , Yinon Rudich a, ⁎ a Department of Earth and Planetary Sciences, Weizmann Institute of Science, Israel b Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa, Israel HIGHLIGHTS • Comparison of endotoxin content in sampled marine aerosols in two sites: on-shore and coastal-inland. • Endotoxin annual distribution as well as bacterial genome content is ana- lyzed. • Cyanobacteria are suggested as a source for endotoxins at coastal areas. • Satellite images and back trajectory analyses provide supporting evidence. GRAPHICAL ABSTRACT abstract article info Article history: Received 19 March 2014 Received in revised form 12 July 2014 Accepted 19 August 2014 Available online xxxx Editor: Dr. Lidia Morawska Keywords: Endotoxin Cyanobacteria Marine aerosols Filter sampling Health effects genomic analysis Marine aerosols, that are very common in the highly populated coastal cities and communities, may contain bi- ological constituents. Some of this biological fraction of marine aerosols, such as cyanobacteria and plankton de- bris, may influence human health by inflammation and allergic reactions when inhaled. In this study we identify and compare sources for endotoxins sampled on filters in an on-shore and more-inland site. Filter analysis in- cluded endotoxin content, total bacteria, gram-negative bacteria and cyanobacteria genome concentrations as well as ion content in order to identify possible sources for the endotoxins. Satellite images of chlorophyll-a levels and back trajectory analysis were used to further study the cyanobacteria blooms in the sea, close to the trajec- tory of the sampled air. The highest endotoxin concentrations found in the shoreline site were during winter (3.23 ± 0.17 EU/m 3 ), together with the highest cyanobacteria genome (1065.5 genome/m 3 ). The elevated endo- toxin concentrations were significantly correlated with cyanobacterial levels scaled to the presence of marine aerosol (r = 0.90), as well as to chlorophyll-a (r = 0.96). Filters sampled further inland showed lower and non-significant correlation between endotoxin and cyanobacteria (r = 0.70, P value = 0.19), suggesting de- crease in marine-originated endotoxin, with possible contributions from other sources of gram-negative non- cyanobacteria. We conclude that marine cyanobacteria may be a dominant contributor to elevated endotoxin levels in coastal areas. © 2014 Elsevier B.V. All rights reserved. Science of the Total Environment 499 (2014) 311–318 Abbreviations: Cl-, Chloride; chl-a, Chlorophyll-a; cyano/Na, Cyanobacteria concentrations/Na + content; HCl, Hydrochloric acid; LAL, Limulus amebocyte lysate; LPS, Lipopolysaccharids; MDL, Method detection limit; MODIS, Moderate Resolution Imaging Spectro-radiometer (MODIS); NFW, Nuclease free water; LRW, Pyrogen-free water; qPCR, Quantitative PCR; Na+, Sodium; CSE, Standard endotoxin; DECOS, The Dutch Expert Committee on Occupational Safety and Health. ⁎ Corresponding author. Tel.: +972 8 943 4237. E-mail address: yinon.rudich@weizmann.ac.il (Y. Rudich). http://dx.doi.org/10.1016/j.scitotenv.2014.08.054 0048-9697/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv