Int Marit Health 2010; 61, 1: 41–43 www.intmarhealth.pl Copyright © 2010 Via Medica ORIGINAL PAPER ISSN 1641–9251 Bioaerosols on Tri-city (Gdańsk–Sopot–Gdynia) beaches
Małgorzata Michalska, Maria Bartoszewicz, Monika Cieszyńska, Jacek Nowacki
Medical University of Gdańsk The Interdepartmental Institute of Maritime and Tropical Medicine in Gdynia Department of Environmental Protection and Hygiene of Transport
ABSTRACT Bioaerosol formation is an important process of mass and energy exchange between the sea and the atmosphere by means of droplets of marine dust. Studies of marine aerosol activity developed in the last decades of the 20th century. Those studies revealed that concentrations of bacteria in aerosol droplets were hundreds of times higher than were those measured in superficial marine waters. Moreover, it was determined that aerosol activity at sea can influence the sanitary condition of the air, especially in seaside areas. Examinations of air composition in coastal regions were performed on the beaches of the Tri-city, Sobieszewo, and Komary. Airborne microorganisms were also investigated in the marine zone at the Vistu- la river mouth. The air samples were collected by a filtration method using Sartorius apparatus. The ex- posed filters were then placed onto agar media in Petri dishes and incubated. All measurements are expressed in CFU/m3, i.e. colony forming units per cubic metre of examined air. Meteorological parame- ters such as temperature, humidity, and wind speed and direction were also measured. The obtained results revealed statistically significant trends between the total number of bacteria and fungal spores, and the sampling season. The greatest number of microorganisms was noted in spring and autumn. Cor- relation analysis showed that a statistically significant relationship exists between the microbial abun- dance and the wind direction, wind speed, and the sampling site location. The maximum number of fungal spores was detected in the areas of Gdynia and Gdansk Brzeźno when south-west winds were blowing from the land. The highest number of bacteria was observed at the sampling stations located closest to the Vistula river mouth (Sobieszewo and Komary). Key words: bioaerosol, mesophilic bacteria, psychrophilic bacteria, fungi
INTRODUCTION measured under laboratory conditions the number of bac- Wind, wave action, and physicochemical processes result teria of the species Serratia marcescens that were present in the formation of aerosols at the water-air interface. In ge- in aerosol droplets emitted via gas bubbles travelling through neral, aerosol formation is connected with the mechanisms of an aqueous medium of known bacterial concentration. Du- air bubble bursting due to wind-induced wave breaking, sno- ring the experiment the number of bacteria in the first drop- wfall, rain, and the creation of splatter droplets. Air bubbles let generated from a single bubble that had travelled through can also form on the water surface because of abrupt war- the water column was measured. The obtained results indi- ming in the spring period or increased biological production. cated that the bacterial enrichment coefficient increases The phenomenon of bacterial enrichment of aerosols with the increasing distance travelled by a bubble through was discovered by Blanchard and Syzdek. In a number of the water column. For the suspension of Serratia marce- laboratory studies they demonstrated the existence of the scens, the bacterial enrichment coefficient was 1000 times potential for the occurrence of aerosols enriched with both higher than the bacteria concentration in the water column. bacteria and viruses [1–5]. The above-mentioned authors This phenomenon is explained by the propensity of gas bub-