Marine pollution is one of the most serious problems of environment that poses
a major threat to the human health. Marine pollution is closely coupled to human
demographics. Around the world, pollution has increased in prevalence by the
growing industrialization and the population explosions (Kennish,
1997). During the past three decades, the protection and preservation of
the marine environment has become a primary goal for the international community
and important results have been achieved in controlling the traditional sources
of marine pollution (Frank, 2007).
Marine pollution involves the destruction of the quality of water by contamination.
The major source of contemporary marine pollution, accounting for >80% of
all pollution is land based activities such as industrial discharges, factory
effluents, agricultural wastes and sewage. National Turkish
Bathing Water Directive (TBWD, 2006); Turkish Water Pollution Directive
(TWPD, 2008) and European Community Bathing Water Directive
(ECBWD, 2006) has contributed significantly to the improvement of the quality
of sea water and considered that total coliforms, fecal coliforms, fecal streptococci
and Salmonella sp. are the principal microbiological parameters to be
evaluated. Total coliforms, fecal coliforms and fecal streptococci are bacteria
whose presence indicates that the water may be contaminated with human or animal
wastes. These pathogens can cause diarrhea, cramps, nausea and headache that
may pose a special health risk for infants, young children and people with severely
compromised immune systems. Salmonella sp. is a prime example of water
and shellfish transmitted human pathogen, which is frequently isolated from
the marine environment, where it can remain viable for several hours. A large
percentage of the gastrointestinal symptoms occurring in the general population
of the developed world are attributable to infection (Efstratiou,
The determination of chemicals and trace metals concentrations in sea water
may also useful tool to evaluate the quality of the marine environment and can
elucidate the mechanisms of pollutants (Manfra and Accornero,
2005). Investigations of chemicals such as nitrate, phosphate and toxic
heavy metals such as Arsenic (As), Chromium (Cr), Cadmium (Cd) have special
importance in environmental samples. Their effects range from cancer to neuropathy
to a diarrhea that is potentially harmful, especially in infants. In the past
quarter century, a considerable incidence of bathing water contamination by
hazardous and carcinogenic organic compounds was reported in the United States
The Dardanelles is a narrow strait in northwestern Turkey connecting the Aegean
Sea to the Sea of Marmara. Like the Bosporus, it separates Europe and the main
land of Asia. The Thracian sea is a poorly investigated area located in northeastern
part of the Aegean Sea. Thracian Sea receives the fresh waters from many of
the rivers draining the Balkan Peninsula, as well as large amounts of brackish
water from the Black Sea and Sea of Marmara. Therefore, knowledge of the biogeochemical
process occurring there is of great importance in order to understand the interactions
between the Mediterranean and Black Sea ecosystems (Zeri
and Voutsinou-Taliadouri, 2003).
In this study, microbiological and physico-chemical parameters with trace metal concentration were investigated coastal bathing water in Dardanelles and Thracian Sea.
MATERIALS AND METHODS
Sample collections: The total numbers of 74 bathing water samples were
obtained from Dardanelles (Site 1) and Thracian Sea (Site 2) (Fig.
1). Sampling procedure was carried out according to the methods specified
in TBWD (2006), TWPD (2008) and EC BWD (2006). Briefly, samples were taken 30
cm below the surface of the water. All water samples were collected in sterile
brown bottle (3 L) for microbiological, physico-chemical and toxicological analysis.
All samples were stored and transported in a cold box kept below 4 °C. Analysis
was performed within 6 h of sampling.
Microbiological analysis: A total of 74 samples were examined by using
the Membrane Filter (MF) Technique (Sartorius, 3 branch manifolds) for total
coliforms (100 mL), fecal coliforms (100 mL), fecal streptococci (100 mL) and
Salmonella sp. analyzed in 1000 mL marine water according to American
Public Health Association (APHA, 1998), Slanetz
and Bartley (1957) and United States Pharmacopeia (USP)
(1995) (Table 1).
Physico-chemical analysis: Marine water analyzed for pH, conductivity,
nitrate, phosphate, As, Cd, Cr and CN elements. The pH and conductivity were
measured with a pH meter and ion-selective meter (Sartorius PP 50, Germany).
of water sampling points in Dardanelles and Thracian Sea
incubation conditions and microbiological medias that are used in microbiological
As (Merck, Merckoquant 1.17927) concentration was determined by using visual
test strips. Nitrate (Merck, Spectroquant 1.14942), phosphate (Merck, Spectroquant
1.14543), Cr (Merck, Spectroquant 1.14758) and CN (Merck, Spectroquant 1.14800)
concentration was measured photometrically at 520 nm wavelength (Thermospectronic
Aquamate 2000E UV visible spectrophotometer, USA) by using test kits. According
to the manual descriptions, the minimum detection limits for As, nitrate, phosphate,
Cr and CN were 0.005, 0.2, 0.05, 0.01 and 0.002 mg L -1, respectively.
Statistical analysis: To compare the physico-chemical analysis and heavy
metal concentrations of Site 1 and 2, independent samples t-test was performed
using SPSS 8.0 program package (Anonymous, 1999).
RESULTS AND DISCUSSION
About 5 of 74 (6.75%) marine water samples were of unacceptable quality based on recommended criteria of microbiological (3 of 74, 4.05%) and physico-chemical with trace metal concentration (2 of 74, 2.70%) by TBWD (2006), TWPD (2008) and EC BWD (2006). The dispersions of microbiological analysis of marine water samples are shown in Table 2.
Total coliforms and fecal coliforms are used universally as microbiological
indicators of water quality and are commonly used for determining the quality
of bathing waters. The fecal streptococci, members of the genus Enterococcus
are considered as to be a good indicator because they are more resistant than
coliforms and environmental stress (Gleeson and Gray, 2004).
In this study, total coliforms were isolated from 9 (12.16%), fecal coliforms
from 7 (9.45%) and fecal streptococci from 7 (9.45%) samples. Similar prevalence
rates of total coliforms and fecal coliforms were reported in Belgium, France
and Italy (Figueras et al., 1997). In a study
that was conducted by Arvanitidou et al. (2002)
in Northern Greece, 68.5, 45.2 and 58.4% of 197 bathing water samples were positive
for total coliforms, fecal coliforms and fecal streptococci, respectively. In
another study, the incidence of total coliforms, fecal c oliforms and fecal
streptococci was isolated from 87.1, 80.0 and 97.5% of samples (Efstratiou
et al., 2009). The present study also demonstrated that the mean
load of indicators in Dardanelles (2.1 x102, <101,
<101 cfu 100 mL -1) were lower than Thracian Sea (5.6
x102, 1.5 x101, 2.5 x101 cfu 100 mL -1).
These may be due to the large population producing sewage and strong tourism
Salmonella sp. is not routinely examined in water samples. The efficiency
of indicators to predict the presence of Salmonella sp. has been examined
in several countries. In Greece, Papadakis et al.
(1997) correlated Salmonella sp. detection percentages to coliform
groups. In Spain, Morinigo et al. (1990) recorded
better correlation of fecal coliforms with Salmonella sp. isolation.
In UK, Public Health Laboratory Service (PHLS), 1959
demonstrated significant correlation between the occurrences of total coliforms
and Salmonella sp. Efstratiou et al. (2009)
assessed, the value of total coliforms and fecal coliforms in predicting the
presence of Salmonella sp. The findings showed approximately similarity
with these results. In this study, Salmonella sp. was detected in samples
which had high counts of total coliforms and fecal coliforms. Two of the total
samples examined (2.70%) were found positive for Salmonella sp. The study
which has higher result (13.8%) than ours was done by Efstratiou
et al. (2009). Contrary, according to the annual report of EU in
1991 and 1994, Salmonella sp. was not detected in the seawater of Greece,
Denmark and Luxembourg (Figueras et al., 1997).
The mean concentration of physico-chemical parameters and heavy metals measured in Site 1 and 2 during summer season are presented in Table 3.
Coastal zones are important ecological systems that are facing many problems
with sudden increase of population and rapid economic development (Bald
et al., 2000). In order to solve these problems, physico-chemical
parameters such as pH, conductivity, nitrate and phosphate concentration are
used for an indicator of quality loss. pH may fluctuate rapidly over the day
depending on biological activities in the surrounding environment (Beer
et al., 2006). In this study, all samples had pH levels below the
permitted limits. The highest pH levels were 8.62, 8.33 and the lowest were
7.19, 7.42 in Site 1 and 2, respectively. Similar (Perez
et al., 2008) and lower (Ohline et al.,
2007; Ayon et al., 1999) results were detected
in previous studies.
results of microbiological analysis of marine water samples (n = 74)
1EU Bathing Water Directive 2003; 2Turkish
Bathing Water Directive (TBWD), 2006; 3Turkish Water Pollution
Directive (TWPD), 2008; *Mandatory level is not specified
results of physico-chemical and toxicological analysis of marine water
samples (n = 74)
1EU Bathing Water Directive 2003; 2MAC:
Maximum Acceptable Concentration; 3Turkish Bathing Water Directive
(TBWD), 2006; 4Turkish Water Pollution Directive
(TWPD), 2008; a, bMeans with different letters in a same
line are significantly different from one another (p<0.05); *These
parameters must be checked by the competent authorities when there is
a tendency towards the eutrophication of the water; **The values which
were determined under minumum detection limit, calculated as 0
These differences may be originated from detection methods, sampling procedures,
geographical conditions and climatic factors. On the other hand, significant
differences in pH were found between the Site 1 and 2 (p<0.05). The results
were consistent with the conductivity measurements. Conductivity, the ability
of water to conduct on electrical current, is directly related to the amount
of inorganic substances (salts and minerals). The concentration of Nitrate (NO3)
and Phosphate (PO4) increase the conductivity of the water. It is
also useful measurement to determine the salinity which is the main variable
regulating the concentrations of dissolved materials (Gianguzza
et al., 2002). In the present study, the conductivity of samples
were found with the range of 8410-9310 μS cm -1 in Site 1 and
8000-9250 μS cm -1 in Site 2 (p>0.05). Likewise, Site 1 has
higher nitrate and phosphate concentrations than Site 2 (p>0.05).
In coastal waters, trace metal concentrations tend not the correlate well with
nutrients. Due to the biogeochemical and sedimentological process, coastal zone
may introduce amounts of pollutants including trace metals (Zeri
and Voutsinou-Taliadouri, 2003). Investigations of As, Cr and CN have special
importance in environmental samples. In the present study, As concentration
in Site 1 and 2 was detected 0.010 and 0.009 mg L -1, respectively.
As and its compounds have been used as agricultural pesticides. As coming from
pesticide application is quickly absorbed onto soil particles in treated areas
and lingers for years after treatments has ceased. Due to the high volatility
of As and its compounds, they can be easily delivered to the coastal waters.
On the other hand, lower (Byrd, 1988) and higher (De
Boer et al., 2001; Tornes et al., 2002)
results were detected in previous studies. The difference between the results
may be due to the industrial facilities ranging from bronzing of material, hardening
of shots to laser material and nature of the pesticides applied in agricultural
Cr is a widespread aquatic environmental pollutant which is used in various
industries such as in the galvanization, steel, leather and paint industries
(Hirata et al., 2000). In this study, all samples
were in acceptable levels and ranges belong to Site 1 was found less high (p>0.05).
This range can be explained that there are seven large leather industrial establishments
along the coast in Canakkale city. Moreover, a study performed in the five stations
in Iskenderun Bay in Turkey showed that significant correlation was found between
the metal concentration and temperature, pH, salinity parameters (Turkmen
et al., 2004). In previous studies, higher (Hirata
et al., 2000), lower (Dahab and Al-Madfa, 1997)
and in similar (Yaymtas et al., 2007) concentrations
were reported. The differences may be due to the settlement areas, deep of sampling
point and determination method.
CN, natural compound found in plants and animals, most commonly inputs the
marine waters via the commercial fishing (McClintock and Baker,
2001). The findings were slightly similar to the study obtained by Guven
et al. (2001) and Dzombak et al. (2006).
During next 25 years, world population expected to exceed 7 billion people
by the turn off the century and the coastal population anticipated doubling.
Therefore, marine pollution problems must be effectively addressed at local,
national and international levels in order to avert further habitat and ecological
destruction. In conclusion, it is necessary cleaning of waste waters by infiltration
of effluent from sewage treatment plants, controlling industrial factors and
maintaining water quality controls because aquatic organisms (especially fish
and mussels) accumulate heavy metals in their tissues or organs in higher quantities.
This affects all ecosystems and human health by directly and indirectly as in
food chain (Yaymtas et al., 2007). This study
is a first in Dardanelles and Thracian Sea that the results supply valuable
information about the microbiological and physico-chemical of coastal bathing
water quality. Also the results may help as background reference concentrations
in evaluating the water quality for next studies.