A Comparison of Pollution, Environmental Hazards, Sedimentology, and Geochemistry, in Five Economic Harbors Along the Egyptian Coast of Mediterranean Sea

Heavy metal pollution and its environmental and human risks have become one of the most important global environmental problems. In the current study, the potential heavy metals ecological risks and their pollution status were assessed in ve important harbors (Sidi Krir, Dekhila, Western, Damietta, and Port Said) along the Egyptian coast of the Mediterranean Sea. Twenty-six sediment samples were collected from ve harbors, where eight heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, Pb and Cd) were identied as well as their texture and geochemistry. To gain deeper insights into the human and ecological hazards of the heavy metals, thirteen ecological indices, sediment quality guidelines and multivariate analysis as well as two pathways of exposures to non- carcinogenic and carcinogenic risk of heavy metals for children and adults were evaluated. The data shown that Sidi Kriri harbor recorded the lowest values for heavy metals, for Cu, while Western Harbor had the highest average for Zn Multivariate analysis revealed the contribution of heavy metals to sediment contamination and the geochemical characteristics as well as nearby sources of pollution. Geo-accumulation index, Contamination factor, Toxic units, sum of toxic units, sediment modied hazard quotient, and sediment hazard quotients reected the signicant contribution of Cd to sediments along all harbors. Non-carcinogenic hazard risk index (HI) values along the harbors gave the order: Western> Port Said> Damietta> Dekhila> Sidi Krir. Also, TLCR values for children and adults indicated the irregularly high abundance of heavy metals in harbor sediments that may cause adverse public health effects. &Mean% (r= 0.8860, p ≤ 0.045), Zn&Mean% (r= 0.9673, p ≤ 0.007, Fe&A% (r= 0.9580, p ≤ 0.010), Mn&A% (r= 0.8957, p ≤ 0.040), and Zn&A% (r= 0.9560, p ≤ 0.011). Harbor the values of TP show high values ranging from 913 µg/g. IP are 482 and 882 µg/g and represented 82% the TP, while OP varies between 31 and 244 µg/g. Data reveal a signicant positive association between TP& Zn (r= 0.8994, p ≤ 0.015), IP&Ni (r= 0.9401, p ≤ 0.005) and OP&Pb (r= 0.8521, p ≤ 0.031) which reects the potential adsorption of phosphate forms with their compounds. Also, the relationship of TP and F (r= 0.893, p ≤ 0.017) indicates the formation of uorapatite (Ca 5 (PO 4 ) 3 F) (El-Said et al. 2015). p ≤ IP&Sit% -0.8837, p ≤ respectively and IP represents 90% of the TP. It is observed that TP and IP show a positive correlation with F (r 0.9249, p and r= 0.023, respectively). contents in surface sediments of all studied harbors are much signicantly higher than those of the Sidi Krir Harbor. this harbor relatively remote from the mainland with fewer human impacts such as agricultural activities, land-based of p ≤ 0.007), Cd-Ca (r=0.9798, p ≥ 0.003), and Cd-Mg (r=0.9748, p ≥ 0.005) are obtained. In Western Harbor, heavy metals accumulation in sediments due to pollution sources is demonstrate by the following correlations of Zn-Li (r=0.8430, p ≥ 0.035), Zn-F (r=0.8519, p ≥ 0.031), Cd-Cr (r=0.9934, p ≥ 0.000), and Pb-B (r=-0.9553, p ≥ 0.003). In Damietta Harbor, the relationships of Zn-Pb (r=0.9456 p ≥ 0.015), Zn-Cd (r=0.9406, p ≥ 0.017), Cd-Pb (r=0.9924, p ≥ 0.001), Zn-Ca (r=0.9024, p ≥ 0.036), Zn-Mg (r=0.9241, p ≥ 0.024), Zn-K (r=0.9487, p ≥ 0.014), Pb-K (r=0.9218, p ≥ 0.026), and Cd-K (r=0.9497, p ≥ 0.013) are obtained. In Port Said, there are many correlations between Ni-Fe (r=0.9468, p ≥ 0.015), Ni-Mn (r=0.9217, p ≥ 0.026), Zn- Cu (r=0.9902, p ≥ 0.001), Zn-Li (r=0.9349, p ≥ 0.020), Cr-Na (r=0.9211, p ≥ 0.026), Cd-Li (r=0.8879 p ≥ 0.044), Cd-F (r=0.9355, p ≥ 0.019), Cd-K (r=0.9673 p ≥ 0.007), and Cd-Cl (r=0.8916


Introduction
Heavy metals are the main man-made pollutants in the global coastal and marine environment. Due to potential toxicity, multiple sources, and cumulative pollution, pollution of the coastal environment is one of the environmental issues that arouse the attention of the scienti c community (El Barjy et al. 2020). It was pointed out that more than 99% of the heavy metals entering the marine water system are stored in the sediment in various ways, that is, the sediment can be used as a large heavy metal storage pool (Shen et al. 2019). Sediment's heavy metals originate from both natural and human sources (Deng et al. 2020). Heavy metals in marine systems can be released into the water column under appropriate parameters and affect the ecosystem. Over time, the further development of human activities has increased the toxicity of heavy metals and integrated them into the food chain by transferring them from sediments to the marine environment. Thus, the accumulation of heavy metals in marine organisms and nally in human consumers has become an issue of concern in modern society as they threaten their health.
Several conventions and international organizations have been established heavy metals-based indices to assess marine sediment pollution, and a variety of methods have been used to evaluate heavy metal pollution and its potential environmental hazards in sediments. These methods include the enrichment factor (EF), contamination factor (C F ), and geoaccumulation index (I geo ), Enrichment factor (EF), Contamination factor (C f ), degree of contamination (C d ) and pollution load index (PLI) methods. Although these methods cannot provide information about the toxicity of heavy metals, they cannot fully re ect the overall toxicity of heavy metals (Liu et al. 2019). Therefore, a potential ecological risk index (PERI) method was proposed to compensate for this shortcoming, and it has become a popular method for evaluating heavy metal pollution in marine sediments.
The Sediment Quality Guidelines (SQGs) is necessary to detect contaminated sediment hotspots and the potential impact of contaminated sediments on benthic organisms (Enuneku 2018). By comparing the concentration of sediment pollutants with the criteria for quality matching, sediment pollution can be estimated . These guidelines can also help clarify sediment quality.
Two criteria were developed: the low and median range effects (ERL/ERM) and the threshold/probable effect level (TEL/PEL). The low range (ERL or TEL) values were reported as a pollutant contaminant with a relatively low impact on biological communities. Under this concentration, there would be rare adverse effects upon on sediment-dwelling animals. On the other hand, ERM and PEL values represent contaminant concentrations above which adverse effects are likely to occur Long and MacDonald 1998). These SQGs were developed based on sediment toxicity information collected for freshwater and saltwater sediments throughout the USA and were developed in a manner consistent with the TELs and PELs for freshwater sediments (Smith et al. 1996). Human health risk assessment of potentially toxic heavy metals provides an indication of the risk level due to pollutant exposure, and it is based on the characterization or quanti cation of the risk level either as carcinogenic or a non-carcinogenic risk (Cherf et al. 2016).
The current research plan was to sample sediments from ve harbors, which are named: Sidi Krir Harbor, Dekhila Harbor, Western Harbor, Damietta Harbor, and Port Said Harbor(1) to identify the spatial distributions of some heavy metals in the sediments; (2) to state the metal pollution status using some established guidelines and pollution indices; (3) to follow heavy metals ecotoxicity by different ecological indices; (4) to estimate the impact of heavy metals on human health; (5) to estimate the potential sources of heavy metal contamination by using the multivariate statistical analysis. Sidi Krir Harbor (A) is located on the west coast of Alexandria City. It is a typical carbonate province with an open coastal environment. It lies between Latitudes 31.05º and 31.09º N and Longitudes 29.58º and 29.70º E (Fig. 1). The near shore seabed is characterized by a relatively gentle slope, while the seabed is steep and the continental shelf is very narrow or missing (Abdel-Halim et al. 2016). The shore is mostly sandy, with a relatively wider beach. There are various activities in the area such as: a power plant that use tar instead of natural gas for a long time, the Arab Petroleum Pipe Company SUMED (Suez, Mediterranean pipeline), and some tourist villages that may dispose of waste directly into the sea without treatment, resulting in serious pollution in the area.

Materials And Methods
Dekhila Harbor (B) is located on the western side of El-Mex Bay (Fig. 1). It is a semi-enclosed basin constructed in 1986 for the export of manufactured iron and steel and the import of coal (Heneash 2015). It also plays an important role in the export and import of other goods such as minerals, ores, fertilizers, salts and grain. The surface area of the harbor is about 12.5 km 2 and the water depth ranges from 4 to 20 m. The harbor's water is exposed to several sources of wastewaters coming from the El-Mex Bay through El-Umoum drain.
Western Harbor (C) is considered one of the most important and largest harbors in the Mediterranean (Fig. 1). The length of the Western Harbor is 7 km and the maximum width is 2 km (Saad et al. 2003). The depth of its water ranges from 5.5 to 14.0 m and its region is divided into internal and external mouths of 200 acres and 600 acres respectively. It is a shallow and semi-enclosed basin that directly receives variable volumes of drainage from the Nubariya Canal (≈ 9000 m 3 /day) and El-Umoum drainage. Due to the prevailing winds the drainage waters of Nubariya Canal and El-Umoum drain enters WH area. The harbor also suffers from intense marine activities, including the import of fertilizers, coal, cement, and export of oil. Harbor (C) is under pressure from various pollutants from different external and internal sources. The external pollution originates from household, industrial and agricultural waste. In addition, a large amount of untreated sewage and industrial waste are also dumped directly into Western Harbor from multiple outlets. The internal pollution originates from different shipping wastes other than discharges generated during the loading and unloading of imported and exported industrial raw materials.
Damietta Harbor (D) is a marine harbor located west of Damietta City on the coast of Nile Delta in Egypt (El-Gharabawy et al. 2011). It was constructed in 1982 for about 10 km west to Damietta outlet of the Nile River. It is semi-closed water body with an area of about 11.8 x 10 6 m 2 , and it is situated between Latitudes 31.29º N and Longitudes 31.45º E (Fig. 1). The harbor is mainly affected by loading/unloading operations, municipal and agricultural waste from Damietta Governorate. It is mainly affected by human activities including shing.
Port Said Harbor (E) is located on the northern entrance of the Suez Canal and is considered one of the most important Egyptian ports. Due to its privileged location at the entrance of the largest international shipping corridor (Suez Canal) and in the middle of the largest commercial shipping line connecting Europe to the east and the largest transit port in the world. Its total area about 3,000,800 m 2 , with water surface is 1.733.800 m 2 and land surface area is 1.267.095 m 2 . It is situated between Latitudes 31.15˚ N and Longitudes 32.18˚ E (Fig. 1). Most of the days of the year and the prevailing winds are moderate to moderate northwesterly winds, with 50 cm tides. Damietta and Port Said are exposed to agricultural drains contaminated with hazardous industrial wastes, domestic sewage, organic matter, fertilizers and pesticides, in addition to oil pollution from ships and oil terminal (Soliman et al. 2015).
Sampling and elemental analysis 26 surface sediments samples were taken from A (Sites 1-5), B (Sites 6-10), C (Sites11-16); D (Sites 17-21) and E (Sites 22-29) using Ekman grab sampling tool during winter 2018 (Fig. 1). The collected sediment samples were transported to the National Institute of Oceanography and Fisheries in an ice box. In the laboratory, samples were stored in polypropylene bags and kept in the freezer at (-20 ºC) processing and analysis. Each of the frozen sediments were spread separately on glass plates and dried at room temperature. Each of the sediment samples was frozen dried, then grind with a pestle and mortar and sift to pass a 63 µm mesh sieve. A portion of each sediment sample was washed and dried at 105 ºC for mechanical analysis (Folk 1974). The total organic carbon (TOC) content was determined by oxidation (Loring and Rantala 1992). Total carbonates were estimated as described by Molnia (1974). The total, inorganic, and organic phosphorus contents (TP, IP and OP) were determined (Murphy and Riley 1962;Aspila 1976). Fine powder sediment samples were digested in closed Te on vessels with a mixture of concentrated HNO 3 , HClO 4 , and HF acids (3: 2: 1 v/v, respectively; Oregioni and Aston 1984). Heavy metals concentrations were measured in the sediment solution digested using a Flame-Atomic Absorption Spectrophotometer (FAAS, Shimadzo 6800, with Autosampler 6100). Na, K, and Li concentrations were measured using a ame photometer (JENWAY PEP7). Calcium and magnesium levels were volumetrically determined (APHA-AWWA-WPCF 1999). Total boron concentration was determined by curcumin colorimetric method (Bingham 1982). Fluoride was extracted following the fusion procedure (Jeffery 1975). Fluoride ion concentration was determined by a colorimetric procedure for zirconium alizarin red S. (Anselm and Robinson 1951;Masoud et al. 2004). Colorimetric determination of both boron and uoride was performed by UNICO UV-2000 spectrophotometer.

Quality assurance
The accuracy of the chemical analysis was veri ed with a sediment reference material (IAEA-405, International Atomic Energy Agency, Austria), which was analyzed with sediment samples during analysis. Results indicated good agreement between the reference material and analytical levels with recovery rates for heavy metals selected from the standard reference material of 95.5-100.2%.
Environmental risk assessment of heavy metals Some indices (EF, I geo , CF, C d , mC d , PLI, RI, TRI, TUs, mPELQ, mERMQ, HQ sed and mHQ sed ) were applied to verify the geological and anthropogenic sources of heavy metals in the different harbors examined (Table 1). Variation in pollution and ecological risk indices results from the difference in the applicability of these indices to sediment pollutants (Omran 2016). Table 1 The applied risk assessment indices Human health risk assessment Exposure to toxic heavy metals may be of great concern to humans who live near polluted aquatic ecosystems. There are two pathways of exposure to heavy metals in sediments, called ingestion (Ing), and dermal (Derm). These exposures can be calculated using equations below equations (Kusin et al. 2018): The exposure factors used in the calculation of chronic daily intake (CDI) are given ( Table 2). The potential non-carcinogenic risk of heavy metal concentrations in sediments is characterized by the use of the hazard quotient (HQ). According to US Environmental Protection Agency, the hazard quotient (HQ) is de ned as the ratio of the chronic daily intake or dose (CDI; mg/kg/day) to reference dose (RfD; mg/kg/day; USEPA 2012) as shown (Kusin et al. 2018;): According to HI values, no signi cant risk of non-carcinogenic will be expected if the value is less than one (HI < 1). However, if HI value exceeds one (HI > 1), there is a possibility of non-carcinogenic risk effects that tend to increase as the HI value increases.
On the other hand, the health risk for carcinogenic heavy metals expressed through incremental excess lifetime cancer risk (IELCR) was determined by estimating the total value of cancer risks for each of the exposure pathways (Table 2)

Sediment characterization
The grain size data reveal that the sediments in Sidi Krir Harbor (A) composed of different types of sand fractions (coarse, medium, ne). The mean size ranges between 0.45 Ф and 2.59 Ф with average value 1.54 Ф ( Table 3). The mean size in Dekhila Harbor (B) uctuates from 3.33 Ф (very ne sand) to 6.19Ф ( ne silt) with an average value 4.68 Ф. The occurrence of ne sediments here may be due to the dominance of terrigenous ne grain size sediments. The inclusive graphic mean size (MZФ) of the Western Harbor (C) ranges between 2.08 Ф ( ne sand) and 6.22Ф ( ne silt) with the average value 4.34 Ф. It was found that, the majority of sediments consist mainly of silt fractions covering the bottom. In Damietta Harbor (D), the mean size ranges from 5.75 to 6.17 Ф. In this harbor the majority of sediments covering the bottom are silt ( ne, and medium). The mean size in Port Said Harbor (E) varies between 3.00 (very ne sand) and 7.04 (very ne silt). However, the differences in grain size distribution can be attributed to the bottom con guration and dominant current regime.    In Sidi Krir Harbor (A), the classi cation of sediments varies from moderately to poorly sorted Ф (Table 3) The percentage of water content (A %) well re ects the sediment texture of the examined sediment samples, and the variation in all different samples is relatively slight, while there is signi cant variation between the ve studied harbors studied ( Sorting(Ø) of the sediment indicates the uctuation in the degree of kinetic energy and the effect of sedimentation system on the grain size characteristics (El-Said et al. 2014). It ranges from poorly sorted to very poorly indicating troubled conditions. Most of the sediments are observed from poorly sorted in Sidi Krir to very poorly locate in Western Harbor, Damietta and Port Said Harbor (Table 3).
Skewness values give information about the symmetry or asymmetry of the frequency distribution of the sediment, and the sign of skewness correlates with environmental energy (Bhattacharya et al. 2016).
Kurtosis plays a vital role in sediment characterization in different environments as explained by Duane (1964) It is also working as on internal sorting or distribution. Friedman (1962) suggested that very high or low values of kurtosis mean that a portion the sediment has achieved sorting elsewhere in a highenergy environment. Almost all studied samples are leptokurtic. It has been suggested that carbonate sands tend to be exclusively leptokurtic or peaked (Pikey et al. 1967). This is related to the dominance of the carbonate sands (El-Said et al. 2014).
Among the examined harbors sediments, the organic carbon content (TOC%) show high values in both the Dekhila and Western harbors (Table 3). TOC% at Dekhila Harbor ranges between 2.4 and 4.0%, while, the higher value is limited to station 3, which includes agricultural drainage, sewage, and industrial wastewater from Lake Mariout through El Umoum drain, heavy ship tra c, export, and import activities. And the high values of TOC% (1.74 -5.63%) are recorded in most of the Western Harbor stations, which are severely affected by agricultural runoff from the El-Mahmoudiya and Noubaria canals and are also affected by household waste. Generally, the low organic carbon content in most harbor sediments is due to reduced bioactivity and good aeration of bottom sediments, as most of the sediment organic matter is oxidized and washed out. The distribution of total organic carbon in the studied harbor sediments is strongly in uenced by the amount of CaCO 3 .
The total silicate content ranges between the maximum (84.0%) value in Damietta and the minimum in Sidi Krir Harbor (8.0%;

Heavy metals distribution
The average concentration of heavy metals along the harbors examined indicates that their regions are predominantly Fe and Mn, with the exception of the Sidi Kriri Harbor which is predominantly Fe and Cu (   The cluster of heavy metals grouping and the geochemical parameters analyses also demonstrate the great coordination of these among themselves and with other parameters in each harbor (Fig. 2). The main processes affecting the distribution of heavy metals in sediments are dispersion, precipitation and sedimentation and chemical reactions (Amankwaa et al. 2021 Box Whisker plots for the various detected heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, Pb and Cd) in the sediments of the investigated harbors are represented (Fig.  4). However, the box represents the minimum (Q 0 or 0%, lowest data point excluding any outliers), maximum (Q 4 or 100%, highest data point excluding any

Geo-accumulation index ( I geo )
Almost all harbors examined show that 100% of their stations are uncontaminated by all examined heavy metals (I geo ≤0), except for Cd (Table 6). Cd appears to contribute signi cantly to the sediment pollution in all stations in the studied harbors and I geoCd ranges from moderately to severe to severely polluted. High I geoCd values are observed in the sediments at Dekhila, Western, Damietta and Port Said harbors.

Mean ERM ( m-ERM-Q ) and mean PEL ( m-PEL-Q ) quotients
Amongst the harbors studied, Sidi Krir shows the lowest quotient values of m-ERM-Q (0.07-0.13) and m-PEL-Q (0.12-0.25), representing 9-21% being bio toxic with least potential adverse effects marine on the environment (Table 6). Given the m-ERM-Q values, most of the stations in the harbors examined have 21% of adverse biotoxic effects on the marine ecosystem, whereas, the high m-PEL-Q quotients re ect that about 49% of the potential biotoxicity may occur in Damietta and Port Said harbors. The variability of biotoxicity from one harbor to another may be related to the sediment texture; i.e., the high sediment contamination with heavy metals especially in silty clay sediments as previously reported (Long et al. 2000). However, the highest m-ERM-Q and m-PEl-Q quotients are recorded in the harbors of lower carbonate and higher sand, silt and clay % (Table 3).

Sediment modi ed hazard quotient ( mHQ sed )
According to the mHQ sed , Western Harbor is shown to be highly hazardous for contamination (2.5> mHQ sed > 3) with values of Cu, Ni, and Cd ( HQ values of children are higher than those for adults and show amounts of less than 0.2, re ecting no risk of ingestion and dermal contact with sediment (Fig. 6). THQ values appear approximately below unity except for the harbors of Western (2.6), Port Said (2.5), and Damietta (2.3). Non-carcinogenic hazard risk index (HI) for children and adults shows amounts more than unity and the harbors are said to be not polluted with heavy metals, except for children in the Western (3.2), Port Said (2.9), Damietta (2.6) harbors (Fig. 7). Non-carcinogenic hazard risk index (HI) values along the harbor take the order: Western> Port Said> Damietta> Dekhila> Sidi Krir.
CTR Ing and CTR Derm values for children and adults show values beyond 1.0E-04 ( Figure 7). Also, TLCR values for children and adults indicate the nonuniformly high abundance of heavy metals in the harbors sediments that possibly cause adverse public health effects. This explores that it is necessary to monitor heavy metals involving many industries, agriculture, and wastewaters for exposure risks.

Conclusions
The impact of anthropogenic heavy metal pollution in the sediments of ve economic harbors along Egyptian Mediterranean Sea, was evaluated using multivariate statistical analysis techniques and ecological indices (EF, I geo , CF, C d , mC d , PLI, RI, TRI, TUs, mPELQ, mERMQ, HQ sed and mHQ sed ) to investigate negative environmental impact as well as the geological and anthropogenic sources of heavy metals in the examined harbors. Sediment properties were identi ed by grain size, sorting, skwenes, Kurtosis, water content, besides their geochemistry by determining TOC %, TCO 3 %, TSiO 3 %, TP, IP, OP, Ca, Mg, Na, K, Li, B, SO 4 , Cl, and F. The results re ected that the distribution of total organic carbon in the studied harbor sediments was strongly in uenced by the amount of CaCO 3 .
Sediment quality guidelines (SQGs) indicated that most of the identi ed heavy metals (Cu, Ni, Cr, Pb and Cd) in the studied harbors ranged between TEL and PEL values, except for average the Ni in the harbors of Dekhila and Port Said, which was more than ERM values and Cd contents which were relatively similar to the ERM. Heavy metals contamination was associated with the evacuation of wastewater from phosphate fertilizers and untreated industrial pollutants, along with shipping activities.
The statistical analyses re ected those sediments with smaller grain sizes (clay and silt) had a greater capacity to adsorb P and indicated the formation of HQ values of children were higher than those for adults and showed amounts of less than 0.2, re ecting the lack of risk of ingestion and dermal contact with sediment. While, values of THQ were less than unity except for Western, Port Said and Damietta harbors which re ect expected pollution.
Therefore, it is critical to identify the differences in heavy metals in harbor sediments and their potential environment and public health risks, which allow the management makers to review, assess, manage and provide information, and make a better decision on environmental management of harbors.

Declarations
Declaration of interest

Declarations of interest: none
Funding sources This research did not receive any speci c grant from funding agencies in the public, commercial, or not-for-pro t sectors.

Figure 2
Tree diagram clusters analysis of studied heavy metals among themselves and with geochemical parameters along studied stations in the investigated harbors Figure 3 Factor loadings of the principle components for the studied harbors Box Whisker plots of the examined heavy metals in the studied harbor sediments  Cumulative target risk (a) of ingestion (b) of dermal contact (c) total lifetime cancer risk for adults and children of different heavy metals.