MICROBIOLOGICAL ANALYSIS AND ASSESSMENT OF COASTAL BATHING WATERS IN REGION VARNA

Water contaminated by human and animal excreta may contain a range of pathogenic microorganisms such as viruses, bacteria and protozoa. During the bathing season, water samples are taken and analyzed for Escherichia coli and intestinal enterococci . The aim of these study is to assess the quality of bathing waters along Black Sea Coast in Varna Region from 2012 to 2016. Materials and Methods: The information about microbiological monitoring of coastal bathing waters in Region Varna is received from Regional Health Inspection – Varna. Results and discussion: From May 2012 to August 2016, 1117 water samples were collected and analyzed in the Laboratory of Sanitary Microbiology of Regional Health Inspection – Varna. In the region of Varna, there is a tendency to increase the number of bathing areas with excellent water quality. In Avren Municipality, bathing water was classified as good and excellent. In Shkorpilovtsi – Tsentralen plazh, the bathing water was excellent quality. In Byala Municipality there was a deterioration in the quality of the seawater. During 2012-2016 two of these 17 sites – Riviera, located in resort Golden Sands and St. Elias located in St. St. Konstantin and Elena had excellent bathing water quality. The water indicators of Ofitserski plazhVarna and Tsentralen plazh, Zlatni pyasatsi PSVO were poor, while the indicators of Varna -Yuzhen plazh were satisfying or good. Conclusion: According to the European Environment Agency, the development and improvement of community water supply and collecting system will have a positive effect on the quality of bathing water.


BACKGROUND
Water contaminated by human and animal excreta may contain a range of pathogenic microorganisms such as viruses, bacteria and protozoa.When water is used for swimming and other high-contact activities these organisms may cause infections in the respiratory and gastrointestinal tract.In most cases, the health effects from exposure to contaminated water are minor and shortterm but there is a potential risk for more serious diseases such as hepatitis A, salmonellosis and cryptosporidiosis (1).It is difficult and impractical to measure the levels of all possible pathogens and therefore indicator microorganisms which indirectly tell us the levels of pathogens are commonly used.During the bathing season, water samples are taken and analyzed for Escherichia coli and intestinal enterococci which are indicators for the presence of contamination with sewage, livestock waste, bird faces etc.
The aim of these study is to assess the quality of bathing waters along Black Sea Coast in Varna Region from 2012 to 2016.

MATERIALS AND METHODS
The information about microbiological monitoring of coastal bathing waters in Region Varna is received from Regional Health Inspection -Varna.
In Varna Region, there are four municipalities along the Black Sea coast -Varna, Avren.Dolni Chiflik, Byala and there are 23 bathing areas with one point for sampling included in the monitoring program (Table 1).Microbiological monitoring of bathing waters was made following the indicators included in Ordinance No. 5 for the quality management of bathing water (SG, Issue 53/2008) (2).This Ordinance reflects the EU Bathing Water Directive (2006/7/EC) (3).
One pre-season sample (taken shortly before the starting of the bathing season) and two samples per every month of the active touristic season (June, July, August) were collected from each area.Three samples per month were collected only from Varna-Ofitserski plazh, Varna Zentralen plazh, Varna Yuzhen plazh.Water samples were taken from 30 cm below the surface in sterile bottles of 300-500 ml.
For the microbiological measurements were used the micro plate methods for statistical analysis of the taken water samples.The calculation of the most probable number (MPN) was detected with the help of tables and allowed the detection of the MPN within a confidence interval of 95% with a lower and upper limit.The method was certified after the Bulgarian State Standard BDS EN ISO7899-1 and the BDS EN ISO 93-08-3.For the isolation and enumeration of Escherichia coli, the microtiter technique with MUG (4-Methylumbelliferyl-β-D-glucuronide) has been used.For the isolation and enumeration of enterococci, the microtiter technique with MUD (4-methylumbelliferyl-β-D-glucoside) has been used.
The units used in the Bathing Water Directive are cfu (colony forming units).The MPN gives the statistically expected number of bacteria in the sample.Under real circumstances, the number of bacteria is higher than the colony forming units because they may adhere together.The unit cfu takes this phenomenon into account.The bathing water quality assessment is based on the data obtained for each bathing season and the three preceding bathing seasons.As result bathing waters are classified as "poor", "sufficient", "good" or "excellent" by EEA (Table 2).

Municipality
Bathing

RESULTS
From May 2012 to August 2016, 1117 water samples were collected and analyzed in the Laboratory of In Avren Municipality there is only one bathing area.In 2013 bathing water was classified as good and excellent during the remaining years of the surveyed period.Sanitary Microbiology of Regional Health Inspection -Varna.In the region of Varna, for the period 2012-2016, there is a tendency to increase the number of bathing areas with excellent water quality (Table 3).
In the Municipality of Dolen Chiflik with a sampling point Shkorpilovtsi -Tsentralen plazh the bathing water was of excellent quality during the entire study period (Table 4).In Byala Municipality there was a deterioration in the quality of the seawater.During 2016 at three of the four sampling points the water quality was good, and only in the Luna camping, it was excellent (Table 5).

Table 2 .
Quality of coastal bathing water

Table 3 .
Coastal bathing water quality in Varna Region

Table 4 .
Classification of bathing waters' quality in Municipality of Avren and in Municipality of Dolni Chiflik

Table 5
Classification of bathing waters' quality in Byala Municipality