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The Results Of Bacteriological Examinations 
Carried Out During The Flood Period On The Gulf Of Gdansk Waters 
Malgorzata Michalska& Maria Krolska 
Institute of Maritime and Tropical Medicine 
ul. Powstania Styczniowego 9B 
81355 Gdynia 
Abstract 
The purpose of the study was to establish the impact of pollution load from flood waters, 
carried into the Gulf of Gdansk, on the level of bacteriological pollution in the coastal zone of 
the Gulf. 
The scope of research, materials and methods 
The investigations were conducted from July 18, 1997, until August 8, 1997, and consisted of 
13 sets of measurements. Each set comprised eight parameters, that is, total number of bacteria 
at 20 and 37°C, most probable number (MPN) of coliform bacteria, MPN of faecal coliforms, 
number of staphylococci in 1 ml, number of faecal streptococci in 1 ml, the presence of 
Pseudomonas fluorescens, Pseudomonas aeruginosa and Salmonella. The investigations were 
conducted at 12 sampling sites located along the coastline between Komary and Gdynia, and in 
the mouth of the Vistula River. Overall, 302 samples were collected. 
The measurements were performed in accordance with a prescribed methodology established 
by the Marine Environment Protection Commission (MEPC). 
Results of bacteriological study 
The analysis of bacteriological data was difficult because of high variation of the obtained 
values as well as highly diverse pollution levels at particular sites. In addition, the lack of 
correlation among the measured parameters has made the analysis even more challenging. 
MPN of faecal coliform bacteria was assumed to be the main parameter on which the 
evaluation had been based because, according to legal regulations, MPN of faecal coliforms 
constitutes the indicator of suitability of surface waters for recreational use. The obtained data 
show that a sanitary condition of coastal waters at particular sites was changing with high 
variability, rendering the interpretation of the results difficult. The only noticeable trend was 
the peak pollution during the period July 24-28, 1997, and a gradual decrease of the pollution 
level afterwards (particularly after July 31, 1997). 
The collected data indicate a pronounced impact of flood waters on the overall level of 
bacterial pollution in sea water as pointed out by: 
• high total bacteria number (TBN) ranging up to tens of thousands, whereas the average 
abundance is about couple hundred. 
• a visibly increased index of faecal streptococci reaching its maximum at 700, and averaging 
from 40 to 160. 
• a high number of staphylococci amounting, on average, to several bacteria with a 
maximum of 200, whereas its value never exceeded 10 during earlier studies conducted in 
the same area. 
It should be stressed that never before has the presence of Staphylococcus aureus been 
detected, however, some saprophitic staphylococci had been found. During the period of