The Gulf of Suez is a relatively young rift basin, dating back 40 million years. It stretches some 280 km to north, terminating at the City of Suez which is the entrance to the Suez Canal (Figure 1). It is relatively shallow, with a maximum depth of about 64 m; outside its mouth the depth drops sharply to about 1255 m. It has a relatively flat bottom with a depth ranging between 55 and 73 m. Hence, the Gulf spreads a shallow basin filled with the surface water of the Red Sea. The climate is arid, with a yearly average net evaporation of 10 mm/day. Winds blow mainly from the north-northwest direction throughout the year. Rainfall in the region is extremely sparse and localized.

The sources and causes of water pollution in Suez Gulf Region can be categorized into: sewage, persistent organic solids, radioactive material, heavy metals, oils (hydrocarbons), nutrients, sediment mobilization, and litter. The mid-western side is locating under the direct effect of sewage wastes and petrochemical effluents of Ras Gharib city. Whereas, the human impact on the eastern (Sinai Peninsula) and southern (El Tour city) sides are still insignificant due to the low population there. For this reason great and rapid development were taken place on these two sides as natural recreational areas

for tourist trades and consequently national income.

Within the framework of EIMP, 12 field campaigns were carried out in 3 years (2011- 2013). A total of 108 coastal water samples were seasonally collected, in duplicate, during March, May, August and October of 2011-2013. Eight coastal sampling stations were selected to represent the different locations situated under the direct effect of human activities, public resort beaches, some protected and reference sites (Figure 1). The latitude and longitude of each station is given in Table 1. Duplicate water samples from each stations were collected at 50 cm depth below the water surface to avoid the floating materials using a high quality and Purified PVC Niskin’s bottle to estimate hydrochemical parameters, i.e., water temperature, salinity, pH, dissolved oxygen etc., eutrophication parameter, i.e., chlorophyll-a, nutrient salts, heavy metals, i.e., Zn, Mn, Ni,

Cu, Cd, Co, Pb, etc., and total petroleum hydrocarbons.

Calibration curves for each variable of nutrient salts and heavy metals were constructed of a blank and four or more standards (Merck Germany). Accuracy and precision were confirmed using synthetic samples and/or reference materials of different nutrient salts and metals and measured every five samples as quality control tools.

A stepwise multiple linear regression to give insight about the relationships between the independent variables and the dependent variables were calculated (n = 106, p ≤ 0.05) to test the relationship between variables. The correlation coefficient is significant at r ≥ 0.195. Analysis of variance (ANOVA) was applied to test significant differences in the measured variables and correlation matrices were constructed from the resulting coefficients with the aid of STATISTICA 10 program. Cluster analysis was applied to organize the observed data into meaningful structures and general categories with the aid of STATISTICA 10 program. Moreover, principle component analysis (PCA) and factor analysis as Varimax normalization rotated were applied with SPSS program version 15.0 for Windows. The number of factors was determined by the total variance explained, i.e. communality, usually more than 85% was necessary.

Beach litter of lumps of new and old tar, oil, feces, sewage disposal, general and harmful liters as well as seaweeds of coastal beach zones especially those used for recreational purposes including pollution index and the magnitudes of pollution for respective items [15] are assessed by eyes according to: none, light, moderate and heavy, allocating respective scores ranging from “0” to “3” (Table 2).

The results of Table 3 of respective years and annual average monitoring for the density, composition, and distributions at different stations cleared out that the shoreline of the Suez Gulf, especially, Ras Gharib (SU06) area was subjected to many factors

which undoubtedly affected the rate of man-made litter accumulation including heavy shipping traffic, intensive commercial fishing, settlement and fast growing communities, etc. [20] [22] [23] [28] [49] [50] . Despite of that the northern parts of the Gulf were still more affected (0.84) by human impacts compared to the southern area (0.73). In fact, the beach tar has been found to be a good estimator of levels of oil contamination and an effective means of evaluating the potential threat of oil on coastal resources [26] - [29] . Stations with a higher pollution index are largely consistent with the areas of oil or natural gas field. In general, the most abundant visible items were general litter as they represented 30.64% of the total items encountered. Oil, seaweeds as well as old and new tar constituted 15.41%, 14.85% and 11.84%, respectively. On contrast, sewage, faces, and harmful litter represented 9.77%, 8.08%, and 3.70%, respectively. Besides affecting the fishing industry and scuba diving tourism, beach litter cause a destruction of living resources and reduces the recreational utility of coastal waters, especially the beaches through shore damage [20] [22] [23] [28] [29] .

The results of water temperature, salinity dissolved oxygen and pH (Table 4), measured at each station by using the CTD (YSI-6000) revealed that the maximum water temperature was 32.21˚C in August, 2012 at Mena Sukhna (Su04); while the minimum

temperature was 17.56˚C in March, 2011 at Ras Gharieb (Su06). Water temperatures showed slightly higher values in the northern parts (25.18˚C) than southern parts (24.18˚C) of the Gulf (Figure 2(A)). Seasonal variations revealed higher temperatures in summer (27.61˚C) compared to their corresponding values (20.38˚C) (Figure 2(B)) suggesting more pronounced variability. In general, variations in water temperature was normal and changed according to many variables such as season, day time, depth, tide, wind, current, water inflow and turbidity [6] [8] [51] [52] . Pronounced variations in the water salinity of Suez Gulf was noticed (Table 4). Regionally, the salinity, in general, showed noticeable local variations according to the distance of the different sites from the effluents [17] [19] [53] - [55] . Based on the distribution of surface salinity in the investigated area, the maximum regional value (42.23 ppt) was observed at Suez North (Su01), while the minimum one (37.65 ppt) was measured at Suez Middle (Su 02). No significant increase in the water salinity of the gulf area from the entrance of the Gulf in the south (40.36 ppt) towards the North (41.51 ppt) revealing a water mass with salinity > 40 ppt and occupying the whole Gulf area (Figure 2(A)). Moreover, seasonal variations showed no differences between winter (41.04 ppt) and summer values (41.34 ppt) of salinity (Figure 2(B)). The distribution of pH values at the surface water in summer showed values ranging from 7.60 to 8.22. In winter, pH values were more or less comparable to that measured in summer with a variation range of 8.09 to 8.24,

reflecting less variation. The observed higher pH values at surface water in summer (8.14) and winter (8.17) seasons could be attributed to the photosynthetic activity and long light span [3] [4] [52] . No obvious variations in the pH values were observed between the southern (8.17) and northern (8.17) parts of the Suez Gulf which is mainly associated with water temperature, dissolved oxygen, organic matter, chlorophyll-a, etc. [7] [17] [51] [53] [54] . It seems that the relative high pH-value, especially at Suez middle (Su02) which is affected by waste waters could be attributed to the phytoplankton bloom and was accompanied by an increase in dissolved oxygen [7] [17] [52] . Dissolved oxygen concentration in the surface water of the Suez Gulf showed concentrations ranging from 4.56 to 7.58 mg/l with an average value of 6.36 mg/l in summer. However, oxygen distribution in winter showed significantly higher values (5.64 to 10.82 mg/l) with an average value of 8.13 mg/l than that of summer which may probably attributed to lower temperatures [16] - [18] [34] . Horizontal distribution of dissolved oxygen concentrations showed higher concentrations in Northern parts (7.44 mg/l) compared to southern parts (6.83 mg/l) of the Gulf (Figure 2(A)) probably due to the higher photosynthetic activity [51] [52] [54] [56] , and consequently indicated a well oxygenated condition (7.14 mg/l) in the whole investigated area. The saturation values are in the range of 72.85% to 171.0% of oxygen depending on temperature and salinity values (Table 4) revealing that the Gulf is nearly super-saturated by oxygen with some tendency towards a slight decrease in oxygen contents with increasing depth. The results of BOD, DOM and COD (mg/l) showed remarkable regional variations (0.64 - 4.72), (0.64 - 3.60), and (9.16 - 12.75) with more or less similar patterns of distribution (Table 4) and revealing higher concentrations depending on the amounts of biodegradable organic matter and impacts of land based sources and/or human activities [16] - [18] [51] [53] [54] [56] . Figure 2(A) cleared out that BOD, DOM and COD levels were higher in Northern parts (2.35, 1.56, and 10.97 mg/l, respectively) compared to southern parts (1.68, 1.14, and 9.71 mg/l, respectively) of the Gulf. Seasonal variations showed concentrations ranging from 0.32 to 4.72, with an average value of 1.75 mg/l, from 0.32 t0 3.2, with an average value of 1.29 mg/l, and from 8.21 to16.82 mg/l with an average value of 9.42 mg/l, respectively in summer (Figure 2(B)). However, BOD, DOM, and COD distribution in winter showed significantly higher values (1.52 - 6.48) with an average value of 3.27 mg/l, (0.64 - 3.84) with an average value of 2.04 mg/l, and (4.54 - 12.27) with an average value of 9.52 mg/l, respectively than that of summer. DOM and COD seasonal variations in coastal surface waters of Suez Gulf were mimic to their corresponding of BOD (Figure 2(B)). According to the Environmental Egyptian law (92/2013), the permissible COD discharge limits (100 mg/l) are much higher than the measured concentrations.

The ranges and mean concentrations of the studied heavy metals, namely, Fe, Zn, Mn, Ni, Cu, Cr, Cd, Pb, and Hg are given in Table 6. The results of the present study (Table 6) indicated that concentrations of most studied metals were quite high especially in the

northern parts of the Gulf. Figure 5(A) cleared out that dissolved metals, i.e. Zn (17.48 μg/l), Mn (2.04 μg/l), Ni (1.66 μg/l), Cu (6.78 μg/l), Cr (1.32 μg/l), Cd (0.88 μg/l), Pb (4.50 μg/l), and Hg (0.112 μg/l) concentrations were higher in Northern parts compared to southern parts (15.60, 1.86, 1.34, 4.38, 1.18, 0.44, 4.07, and 0.050 μg/l, respectively) of the Gulf. Fe exhibited more or less comparable concentrations (39.40 μg/l) in the northern and southern parts (40.78 μg/l) of the Gulf. Generally, concentrations of most dissolved metals exhibited the highest concentrations in the area surrounding Suez City where the bay is subjected to industrial run-off from oil refineries, fertilizer plants, and power station in addition to sewage and garbage [21] [24] [62] [63] . Based on the mean annual values, the concentrations of dissolved metals in the northern and southern Suez Gulf followed the following order: Fe (39.40 ± 4.78 μg/l) Zn (16.46 ± 14.75 μg/l) Cu (6.93 ± 4.34 μg/l) > Pb (4.66 ± 4.16 μg/l) > Mn (2.30 ± 2.53 μg/l) >

Ni (1.66 ± 1.31 μg/l) > Cr (1.38 ± 1.21 μg/l) > Cd (0.67 ± 0.40 μg/l) Hg (0.12 ± 0.046 μg/l). In general, Hg, Cd, Cu, Ni, Zn, Cr, Mn, and Pb concentrations were almost 2.24, 2.00, 1.60, 1.24, 1.12, 1.12, 1.10, 1.10 times, respectively higher in the northern parts compared to the southern ones (Figure 5(A)). Fe concentrations, on the other hand, were 1.04 times higher in the southern parts compared to the northern ones. The high values of most metals in the northern parts are mainly due to allochthonous huge amounts of domestic and drainage effluents from El-Kabanon drain in addition to the fertilizer waste from El-Nasr fertilizer factory [3] [6] [7] . However, the relatively higher concentrations of Fe in the southern parts are due to the more oxic conditions in the southern area of the Gulf. Seasonal variations showed concentrations of Fe ranging from 21.779 to 64.115, with an average value of 44.1 μg/l, Zn ranging from 10.783 to 49.406, with an average value of 22.46 μg/l, Cd ranging from 0.467 to 4.816, with an average value of 1.06 μg/l, and Hg ranging from 0.006 to 0.489, with an average value of 0.095 μg/l, which were significantly higher in winter compared to their corresponding values (19.79 - 75.56, 41.82 μg/l), (3.992 - 21.569, 11.60 μg/l), (0.146 - 0.75, 0.34 μg/l), and (0.028 - 0.1772, 0.064 μg/l), respectively in summer (Figure 5(B)). On contrast, seasonal distributions of Mn (0.256 - 17.25, 1.92 μg/l), Ni (1.013 - 2.204, 1.58 μg/l), Cu (1.72 - 23.587, 6.32 μg/l), Cr (0.326 - 3.900, 1.29 μg/l), and Pb (2.823 - 9.99, 3.74 μg/l) exhibited significantly higher values in summer compared to their corresponding values (0.047 - 4.36, 1.45 μg/l), (0.894 - 1.825, 1.34 μg/l), (1.684 - 5.07, 3.16 μg/l), 0.64 - 1.341, 1.08 μg/l), (2.613 - 4.002, 3.60 μg/l), respectively in winter (Figure 5(B)). Except for SU 01 & Su 02, the present study revealed that all water samples exhibited dissolved heavy metals concentrations in the international acceptable ranges [64] . Stations (SU 01 & SU 02) attained Hg concentrations slightly higher than the permissible levels.

Total petroleum hydrocarbons in Suez Gulf ranged from 0.56 and 2.38 µg/l with an average of 1.35 µg/l (Table 6). The maximum concentration in all studied locations was measured for Suez north (SU01) and the minimum one was observed at Suez south (SU03). The coastal waters at the northern parts are more suffered from oil pollution (2.06 µg/l) compared to the southern parts (1.60 µg/l) of the Gulf (Figure 5(A)). The higher concentrations are mainly attributed to accidental, deliberate or operational discharges and spills of oil from ships, especially tankers. Offshore platforms and pipelines are additional reasons for the increase of total petroleum hydrocarbons in the northern Suez Gulf. Stations of SU02 and SU06 in the Gulf of Suez (2.88 & 2.47 µg/l, respectively) were found to suffer from extensive chronic petroleum pollution inputs compared to other areas of the Gulf. The impacts of oil pollution land-based sources and/or offshore sources are the main reasons for such increase [20] [22] [23] [26] [27] . Furthermore, seasonal variations showed concentrations of petroleum hydrocarbons ranging from 0.18 to 9.0 µg/l, with an average value of 1.70 µg/l which were significantly higher in winter compared to their corresponding values (0.56 - 3.57, av. 1.52 µg/l) in summer (Figure 5(B)). The lower concentrations of petroleum hydrocarbons in summer are mainly attributed to the increase in the rate of evaporation for petroleum hydrocarbons in summer season due to the increase in water temperature and water salinity [20] [22] [23] [26] [27] . In general, the maximum concentration was much lower than the harmful concentrations reported for seawater. On the other hand, the reported concentrations are very far below the accepted level given by EEAA of Egypt and that recorded by the International level of 500 µg/l.