Coastal water is an important economic and recreational resource that is affected by human activities 1. Among the diversity of human activities and sources of pollution, one can distinguish three main ways in which pollutants enter the marine environment: direct discharge of effluents and solid wastes into the seas and oceans (industrial discharge, municipal waste discharge), land runoff into the coastal zone, mainly with rivers, and atmospheric fallout of pollutants transferred by the air mass onto the seas’ surface 2. Other recreational water activities such as marinas and boating activities may add to the pollution of recreational waters. Chemicals used to maintain and repair boats, including solvents, oils, paints, and cleansers, may spill into the water or seep into the water bodies through runoff. Sanitary wastewater from poorly maintained boats, or poorly maintained pump-out stations at marinas, can significantly increase the bacteria and nutrient levels in water 3.
The Mediterranean Sea is exposed to chemical pollution, bacterial contamination, and eutrophication, mainly from inputs from rivers, especially along the African shores. The problems are mainly in semienclosed bays, some of which still receive large amounts of untreated sewage 4.
Alamein Marina Lagoon is one of six lagoons lying on the Egyptian Mediterranean Coast (Fig. 1). It is located on the western coast stretch, 94 km west of Alexandria City. It was originally composed of several independent natural lakes, used to be prior 1988 as athalassic hyper-saline lakes, lying behind the coastline and separated from the sea by a narrow coastal ridge. Between 1988 and 1995, a large-scale recreation compound or center called the Alamein Marina Center was established to contain most of these historic Alamein lakes. The center extends 12 km along the shore at 1.0–2.0 km width 5.
The development of the recreational marina and the provision of a safe water body for bathing activities implied that the natural lakes became not only connected to each other but also to the Mediterranean Sea by four man-made inlets. In order to stabilize the four inlets and maintain continuous water exchange, five offshore jetties and eight groins were constructed. Of the five jetties, two are used to control the main navigational channel of the big elongated basin (EB) of the lagoon. In addition, the Alamein Marina Center has become fully occupied with houses and summer-related facilities. Such touristic activities could have an impact on the water quality of the recreational lagoon.
The aim of the study is to assess the quality of Alamein Marina Lagoon water in an attempt to evaluate the environmental impact of the touristic summer activities on the lagoon and to determine at what level this recreational lagoon stands as a healthy resort, among the other resorts around the Mediterranean Sea Basin.
Materials and methods
Description of the study area
The Alamein Marina Center, including the recreational Alamein Lagoon, extends 12 km along the Mediterranean shoreline at 1.0–2.0 km width. The lagoon is elongated, parallel to the sea coast, and is currently connected to the Mediterranean Sea through four inlets protected by six jetties. These jetties are perpendicular to the shoreline with lengths varying from 350 to 1250 m (constructed in the period from 1989 to 1993). In addition, eight short groins with lengths varying from 150 to 400 m with artificial nourishment have been constructed in the area between the lagoon outlets in the period from 2002 to 2003 6.
Sampling sites and timing
The lagoon under study consists of four connected sub-basins. The sub-basins have been given arbitrary local names. These are, from the east through the west, (a) small round basin (RB), (b) EB, (c) west basin (WB), and finally (c) the far-west basin (FWB). Their depths range from 1.8 to 6.5 m. The EB is the deepest whereas RB is the shallowest. The EB has the greatest surface area and RB has the smallest surface area.
Fourteen sampling stations were chosen to represent the four sub-basins of the lagoon and its outlets on the Mediterranean Sea. The number and position of the stations are shown in Fig. 2.
Four successive seasonal cruises representing the four seasons of the year were carried out in Alamein Marina Lagoon, in the period between April 2007 and February 2008, during which water samples were collected from the 14 sampling stations according to their depth: at sites where the water depth exceeded 2 m, surface and bottom water samples were collected, whereas one surface water sample was collected from shallow sampling sites.
Determination of Alamein Marina Lagoon water characteristics
Some parameters were determined in situ such as pH and temperature and others were determined after transport of the samples to the laboratory. These include dissolved oxygen (DO), biochemical oxygen demand (BOD), total nitrates, total phosphates (TP), and bacteriological parameters including heterotrophic plate count (HPC), fecal coliform (MPN/100 ml), and Streptococcus faecalis (MPN/100 ml). All analyses and measurements were carried out according to the methods described in the Manual of Seawater Analysis by Strickland and Parsons 7, except BOD and bacteriological analyses, which were carried out according to the method described in Standard Methods for the Examination of Water and Wastewater8.
All statistical parameters were determined on Excel Version 2007 (Microsoft, USA).
Results and discussion
The pH range in Marina Lagoon was almost constant throughout the study period and across all the different sampling stations of the entire lagoon (Table 1). It fluctuated between 6.8 and 7.9, indicating a neutral state in the lagoon. Neither a seasonal nor a regional change was observed. In terms of the vertical distribution of water, the pH ranges in the surface samples and the bottom samples were also almost the same.
Water temperature is a measure of the intensity of heat stored in a volume of water. The heat content of any water body reflects the instantaneous balance among inputs, storage, and outputs 9.
The lagoon has a normal distribution pattern of water temperature with time. The general trend is the same as that in the overlying air. The lowest temperature was in winter (15°C) and the highest one was detected in summer (31°C).
In terms of the vertical distribution, the mean surface and bottom values were similar to each other and a low negative mean difference of −0.1 was recorded (surface=21.7 and bottom=21.6). This indicates the presence of homothermal water columns for the entire lagoon and in each of its four regions individually.
The average values of water temperatures in each basin showed that RB was slightly warmer, and this could be attributed to its shallowness (Table 1). According to Walling and Webb 10, the water temperature within a water body is influenced by latitudes, altitude, season, and time of day. It can also vary in response to air circulation, wind energy, cloud cover, currents and other water movements, and ground water seepage. Moreover, the morphometry of the channel and depth, shape, orientation, in addition to substratum conditions, and silt content of water also affect the water temperature 10.
The distribution of DO in inland waters is governed by a balance between inputs from photosynthesis in addition to the physical processes of gas exchange from the atmosphere. Water depths, time of the day, and vegetation cover are among the factors identified as affecting oxygen concentration 11.
The average DO concentration in Alamein Marina Lagoon throughout the study period was 6.35 mg O2/l for the surface samples and 6.63 mg O2/l for the bottom samples. This indicates that the lagoon resembles an orthograde curve, which is a characteristic of the ultraoligotrophic lakes 9.
In terms of the minimum DO level (3.36 mg/l), this was determined in the summer season in four sampling stations from the EB and the WB. The maximum DO level (11.46 mg/l) was determined in one of the stations of the EB in the autumn season. A negative correlation was found between DO and water temperature (r= −0.74 and −0.54 for surface and bottom water samples, respectively). It seems likely that the presence of DO in the lagoon is mainly controlled by physical factors (temperature reducing the solubility of the gas in water) rather than biological factors.
The local averages of DO in each of the four basins of the Alamein Marina Lagoon during 2007–2008 were very close to each other, showing no regional variation in the mean level of DO throughout the entire lagoon (Table 2). They were in the following order: RB (6.6 mg/l)>FWB (6.54 mg/l)>EB (6.5 mg/l)>WB (6.3 mg/l).
Biochemical oxygen demand
The average BOD in the Alamein Marina Lagoon throughout the study period was 1 mg/l (0.97 mg/l for the surface samples and 1.11 mg/l for bottom samples). Consequently, the lagoon water was of very good quality, on the basis of the classification of Chapman 12 , as water has BOD values less than 2 ppm.
In terms of the minimum BOD concentration, it was found that BOD was not detected during the summer season in two surface water sampling stations in the WB as well as in a bottom station in the EB. The maximum BOD concentration (2.51 mg/l) was determined in one of the stations of the FWB in the winter season. According to Goel 13, the lagoon is almost free from pollution with oxygen-consuming matters including sewage resulting from anthropogenic activities.
In addition, the results of the present study do not differ from those obtained from a study carried out 45 years ago, in 1966, in the Arab Bay in Mediterranean coastal water in front of Marina Lagoon. The maximum value of BOD reported in the previous study was 2.4 mg/l, and it was recorded in winter 14. This shows that the recent construction of the recreational resort around the lagoon did not impact its water quality.
The local averages of BOD in each of the four basins of Alamein Marina Lagoon during 2007–2008 were very close to each other, showing no regional variation in the mean level of BOD throughout the entire lagoon (Table 2). They were in the following order: FWB (1.15 mg/l)>RB (1.04 mg/l)>WB (0.98 mg/l)>EB (0.9 mg/l).
Similarly, on the vertical scale, there was no significant difference in the BOD concentration: the mean value of surface water samples was 0.97 ppm and that of the bottom samples was 1.28 ppm.
The average TP concentration in Alamein Marina Lagoon throughout the study period was 0.5 μg/l (0.47 μg/l for the surface samples and 0.68 μg/l for bottom samples), indicating a state of unproductive unpolluted water of the lagoon.
The minimum TP concentration (0.06 μg/l) was detected during the autumn season in both the EB and the WB. The maximum TP concentration (7 μg/l) was determined in one of the stations of the EB in the summer season. This drastic increase in the TP concentration in summer could be attributed to summer activities of the inhabitants of Marina Resort. Nevertheless, this high TP concentration was still far below the acceptable concentration of phosphates in natural unpolluted waters, which is 20 μg/l 15.
The local averages of TP in each of the four basins of Alamein Marina Lagoon during 2007–2008 were very close to each other, showing no regional variation in the mean level of TP throughout the entire lagoon (Table 3). They were in the following order: EB (0.94 μg/l)>RB (0.44 μg/l)>FWB (0.4 μg/l)>WB (0.32 μg/l).
In terms of the vertical scale, the mean bottom values were slightly higher than the surface values (mean surface TP=4.32 μg/l and mean bottom TP=6.18 μg/l). This could be because of sedimentation of the nondissolved phosphate suspended in the lagoon water.
The average nitrates-N concentration in Alamein Marina Lagoon throughout the study period was 3.8 μg/l (4 μg/l for surface samples and 3.6 μg/l for bottom samples). The minimum nitrates-N concentration (0.15 μg/l) was detected during the autumn season in the EB. The maximum nitrates-N concentration (20 μg/) was determined in one of the stations of the FWB in the winter season.
The local averages of total nitrates in each of the four basins of Alamein Marina Lagoon during 2007–2008 were very close to each other, showing no regional variation in the mean level of nitrates throughout the entire lagoon (Table 3). They were in the following order: RB (7.33 μg/l)> FWB (6.7 μg/l)> WB (2.8 μg/l)> EB (1.85 μg/l).
In terms of the vertical scale, the mean surface nitrate concentration was slightly higher than the bottom (mean surface=4.01 μg/l and bottom=3.66 μg/l).
Such low concentrations of nitrate-N in Marina Lagoon are in agreement with those of Wetzel 9, who reported that the nitrate concentration is highly variable seasonally, regionally, and spatially within lakes, and that it could range from undetectable levels to almost 10 mg/l in unpolluted waters. They were also in agreement with those reported in previous studies on the Mediterranean Coastal water. Examples include the study carried out by Fahmy et al. 16,17, which reported an annual mean concentration of nitrate-N in Arabs Bay of 0.86 and 0.25 μg/l, respectively. A third study (Fahmy, 2001) reported an annual mean concentration of nitrate-N in the North of Sallum of 0.2 μg/l 18.
The bacteriological analysis carried out during the present study yielded total and fecal coliform/100 ml, streptococci/100 ml, and HPC/ml (Table 4).
In the winter season, all bacteriological parameters were not detected at all stations of the lagoon.
The spring season was the only season in which the total coliform group was detected. It was detected only at five stations out of the 14 stations under study, namely 5 and 6 in the RB, 3 and 7 in the elongated basin, and 16 in the FWB. The WB was the only basin free from this indicator organism. Total coliform showed a surface general mean of 3.76/100 ml and bottom general mean of 4.33/100 ml. Fecal coliform and streptococci were not detected in the spring season in any of the samples collected from the stations. HPC was detected at all stations, except in the surface water samples of stations 5 and 7. It ranged between complete absence and 370 CFU/ml, and showed a mean concentration of 54.3 CFU/ml for surface water and a mean concentration of 22.2 CFU/ml for bottom water. No statistically difference significant was observed between the results of analysis of surface and bottom water samples in the lagoon for HPC (P=0.98) at a 95% confidence limit.
During the summer season, the total coliform group of organisms was not detected. However, streptococci were detected in all stations, except four, namely, station 6 in the RB, 8 in the elongated basin, 11 in the WB, and 15 in the FWB. Streptococci ranged between complete absence and 460/100 ml, and had a mean concentration of 63.52/100 ml for surface water and a mean concentration of 13.58/100 ml for bottom water. RB was the most polluted basin with streptococci (58/100 ml). HPC was detected at all stations and was ranging between 40/ml up to 4000/ml. It showed the highest general mean for surface and bottom water samples (3138.1 and 2996.1 CFU/ml, respectively). All basins were close to each other in the degree of bacteriological pollution from bathers’ excreta. Similar to the spring season, no statistically significant difference was observed in the summer between the results of analysis of surface and bottom water samples in the lagoon (P=0.69 for streptococci and P=0.73 for HPC) at a 95% confidence limit.
Finally, in autumn, total coliform, fecal coliform, and streptococci were not detected. HPC was found to fluctuate between complete absence and 460/ml. It decreased to a mean concentration of 359.3 CFU/ml for surface water and a mean concentration of 388.9 CFU/ml for bottom water. No statistically significant difference was found between the results of analysis of surface and bottom water samples in the lagoon (P=0.82) at a 95% confidence limit.
The absence of streptococci in all seasons except the summer season could be attributed to the absence of swimmers. This was in agreement with previous studies reporting that the important sources of contamination for both treated and untreated recreational waters were the bathers themselves and that this contamination depends on the density of bathers, the surface area of swimming pools, and the width of outlets where water exchange occurs 19,20.
Public health aspect of the Alamein Marina Lagoon
National and international standards and guidelines
According to the WHO, swimmers are exposed to the risk of many diseases in polluted beaches. These risks include enteric, respiratory, skin, and eye and ear infections. They may be caused by sewage, combined sewer overflows, animal fecal wastes, and bather load 21. Other health risks include sports injuries during diving, falling (slipping), and boating accidents 22.
WHO guidelines for recreational water quality state only one bacteriological parameter, which is an MPN of 40/100 ml for enterococci, besides the neutral pH and the normal water color 23. Australian guidelines have set fecal coliform and enterococci MPN to be 150/100 and 35/100 ml, respectively 24. Egyptian standards for recreational waters set by the Egyptian Environmental Affairs Agency state that water color should be normal, its pH should be neutral (6–9), and BOD, phosphate, and nitrate-N should not exceed 60, 5, and 40 mg/l respectively. In addition, it is stated that fecal coliform should be less than 5000/100 ml 25.
There exist other international regulatory agencies for recreational waters, but the most well-known one is the Blue Flag Organization. The main criterion for the Blue Flag Campaign for beaches is compliance with the minimum seawater quality monitoring requirements for the Bathing Water Directive of European Commission. Blue Flag regulations require the total coliform concentration to be less than 10/100 ml and fecal coliform to be less than 2/100 ml 26.
In the present study, as shown in Table 5, it is was clear that the characteristics of Alamein Marina water complied with the standards set by Egyptian standards during the entire study period. In addition, they also complies with the levels set by different international organizations such as the WHO and Blue Flag. Usually, the reasons for bacterial pollution and sources of contamination of seawater include sewage, industrial effluents, and agricultural runoff (including manure, fertilizers, and pesticides). Other sources of pollution include urban storm runoff, animal feces, infected bathers, and oils and gasoline spills from boats and marinas 27. The absence of all these contaminating factors – except the presence of bathers during the summer season – in the region examined in the present study was reflected in the high water quality of the lagoon and its open sea.
This was in accordance with the findings in the Al-Khiran Area in Kuwait, wherein all the results of the bacteriological analysis of Al-Khiran seawater complied with the Blue Flag Criteria and the National Bathing Water Quality Standards. The high quality of seawater was an indicator of successful wastewater treatment and disposal 28.
Similar findings were obtained in Lake Bardawil, situated on the Egyptian coast of the Mediterranean Sea, where bacteriological analyses showed that fecal indicator bacteria were at acceptable levels according to the Egyptian and European standards 29.
However, in Lake Edku (Egypt) the number of fecal coliform was found to be in violation of the Egyptian Standards and European Commission Standards, especially for the stations near the drains. This could be attributed to the discharge of raw domestic sewage of Edku City and the runoff from agricultural fields and other human activities 30.
Streptococci MPN/100 ml is not a part of the Egyptian Standards for recreational waters either in the WHO guidelines or in the Blue Flag criteria. The WHO uses the enterococci standards instead of the fecal streptococci. Throughout the study period, Marina Lagoon was found to be free from streptococci, except in the summer season, during which collected samples were positive for such indicator organisms. This was in agreement with the Egyptian Coastal Water Monitoring Program, which found a seasonal pattern in the streptococci concentration, with increased levels in July–August because of the high recreational use of the coastal area in this period 31.
According to regions, the study found that the most polluted region of the lake was the RB, with 1117.5 CFU/ml. It also showed the highest local average of streptococci (58.33/100 ml) as shown in Table 4. This could be attributed to the fact that it is a small basin, semi-closed, and has a limited water circulation, where less water exchange takes place. However, the least polluted basin was the EB, with the least local average of streptococci (2.5/100 ml), because of the wider outlets that facilitate water exchange.
In Lake Oswin, close to the Russian border, an investigation was carried out and it was discovered that the number of indicator bacteria ranged from several tens of CFU/ml to several thousands of CFU/ml. On the basis of these numbers, the water examined could be considered as nonpolluted or negligibly polluted. These results varied in the samples examined depending on the research station. In the present study, the lowest numbers were recorded in samples collected from the bay and the highest numbers were recorded in samples collected from the river that drains into the lake 32.
Water quality index
The National Sanitation Foundation (NSF) created and designed a standard index called the water quality index (WQI). It can be used to determine whether a particular stretch of river is healthy. It is a 100-point scale that summarizes the results of nine different measurements when complete: they are presented in Table 6 together with their relative weights. The results of analysis of a particular water body are recorded and transferred to a weighted curve chart, where a numerical value is calculated. For each test, the numerical value or the Q value is multiplied by the relative weighted factor.
The mathematical expression for NSF WQI is given by
where Ii is the subindex for ith water quality parameters, Wi is the weight (in terms of importance) associated with ith water quality parameters, and P is the number of water quality parameters 33.
By calculating the WQI for Alamein Marina Lagoon and its four sub-basins, Table 7 is obtained. Comparing the values obtained with the WQI ranges set by the NSF (90–100 excellent, 70–90 good, 50–70 medium, 25–50 poor, and 0–25 very poor water quality), it is obvious that Alamein Marina Lagoon water has an excellent quality relative to the entire lagoon (93%) and every basin separately as well.
Conclusion and recommendation
The characteristics of Alamein Marina Lagoon water are compliant with the National and International Standards set for recreational water quality. This could be because of proper environmental management within the Alamein Marina Recreational Center. This includes prohibiting disposal of oil from boat maintenance in the lagoon water, sewage collection and disposal in a separate wastewater treatment plant, and good management practices for solid waste generated from Marina inhabitants.
The study recommends the implementation of a routine monitoring program by a continuous analysis of samples collected from many stations in the entire lagoon in order to detect any form of pollution as soon as it occurs, and to take corrective actions to restore the excellent quality of the lagoon water.
Conflicts of interest
There are no conflicts of interest.