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BY-NC-ND 3.0 license Open Access Published by De Gruyter Open Access March 22, 2016

Environmental impact of the Midia Port - Black Sea (Romania), on the coastal sediment quality

  • Irina Catianis EMAIL logo , Constantin Ungureanu , Luca Magagnini , Elisa Ulazzi , Tiziana Campisi and Adrian Stanica
From the journal Open Geosciences

Abstract

The aim of the study was to evaluate the impact of potential pollution sources, mainly from the upstream anthropogenic sources and port-related activities. The in-vestigated area covered a wide range of anthropogenic im-pacts (e.g., industrial wastes, storm water runoff, acciden-tal oil spills, intentional discharges and shipping activities). The quality of water and Sediments was assessed us-ing Standard methods, as physical-chemical parameters, chemistry and biology (microbiology, ecotoxicology) aim-ing to figure the level of pollution and the effect of port-related activities. Seawater quality results agreed generally with environmental Standards. Though, in some samples the concentrations of sulphates (mg/1) and heavy metals (μg/1), as B, As and Se exceeded the recommended lim-its, without posing a serious environmental concern. Most of the surface sediment samples contain critical levels of hydrocarbons (C>12), (mg/kg), polycyclic aromatic hydrocarbons (ng/g) and polychlorobiphenyls (ng/g). For some heavy metals (mg/kg), exchangeable concentrations were found to be very close or above the regulations. The signifi-cance of this study is incontestable taking into account the lack of previous relevant historical data of this area. In this sense, it was possible to indicate, in general, good environmental conditions, despite the industrial and concentrated local port-related activities in the investigated area.

1 Introduction

During the history, the harbors have been gates towards the world, enhancing the trade, the cultural exchange, and the social development. Thus, they have played a considerable role in the global economy, and nowadays, they have concentrated around them a large population. Though, the coastal structures protecting the shipping activities in harbors (e.g., jetties and moles), have also created important problems in the coastal environment (locally or regionally), perturbing the normal water and sediment circulation patterns, leading further to the pollution of the coastal environment. Generally, the ports may be considered the fundamental nucleus regarding the regional economic activity from an area, but at the same time, they are major sources of pollution. The impact of the port-related industries is of significant importance concerning the environmental quality. However, the greatest anthropogenic disturbances originate from the effluent discharges composed of multiple combined components (e.g., Sediments, heavy metals, inorganic nutrients, pesticides) with serious consequences on marine environments [1]. Also, it is emphasized [2], that the indirect effects of chemical pollution have negative implications regarding the aquatic ecosystems.

The coastal sedimentary environments are affected not only by the anthropogenic Stressors; thereby the sediment management issues necessitate covering several aspects [3, 4]. Due to a series of potential contami-nant sources (e.g, industrial and agricultural discharges, sewages, accidental spill from the commercial ship traf-fic, atmospheric deposition), or from other diffuse sources (e.g, shipyards, rainfall, storm waters etc.), the water and Sediments from ports become vulnerable to quality environmental alterations. Considering their high capacity of accumulating anthropogenic pollutants from intensely industrialized sectors, the marine Sediments act as repositories for many contaminants in the aquatic Systems. Marine pollution involves a range of threats, including here, the two main categories of pollutants: heavy metals and organic contaminants that require a Special attention. The fate and behaviour of these pollutants are controlled by many different factors. In contrast to hydrocarbons that can be oxidized and decomposed as a result of bacterial activity, heavy metals, for example, do not decompose, so that they are assimilated into the Sediments. The heavy metals may damage the ecological aquatic balance for many communities and their ecosystems, finally, being considered harmful to humans due to their bioaccumulation and magnification capacity [5]. Lately, the heavy metal’s accumulation in various vegetal (e.g., aquatic plant species) and animal organisms (e.g., fish tissue) have been largely investigated in many parts of the world [6, 7]. The concentrations of heavy metals in aquatic environments (e.g., water and Sediments) can be used as indicators regarding the food chain magnification, the ecological background and the land use modifications in the catchment area [8-10]. Among other anthropogenic activities that cause marine pollution, dredging and dredged sediment disposal are possibly the most significant in terms of pollution dissemination. Dredging is a fundamental activity for the majority of ports contributing to a better development in terms of navigation, flood control, civil engineering works, beach nourishment and the removal of contaminated Sediments, especially where is a high environmental risk [11]. Nevertheless, the dredged Sediments are generally polluted and considered as residual waste.

In a general way, the sediment quality assessment is implemented to approach the risk of re-Suspension during dredging, disposal and beneficial use and/or treatment options [12]. Over the years, a Special attention was dedi-cated to the development of a sustainable dredging environmental management. A series of assiduous investigations along with field experiences performed in the states as the United States, Canada, Netherlands, Germany, Belgium, Japan etc., were the basis for the conception of integrated programs on the management of contaminated dredged Sediments [13-15]. In recent decades, all involved stakeholders around the world have joined their remarkable studies to integrate data regarding the assessment, management and remediation of contaminated Sediments [16], considering ecologic and socioeconomic issues. So, there have been established a series of sediment quality guidelines (SQGs), relates to the Interpretation of historical data, the planning of monitoring programs, the evaluation of sediment contamination, strategies to mitigate contami-nations, future remedial actions, predictability and trends of pollutant loads[1] [17-20]. Conventionally, the approach of contaminated Sediments envisages the assessment of distinct chemical compounds levels and their comparability with agreed environmental Standards. Lately, a number of SQGs have been elaborated for correlating different chemical concentrations in sediment to their potential for biological effects. The estimation of chemical contamination effects on sediment quality requires consideration of a number of issues, due to the laborious comprehension of the biological availability of chemicals in Sediments. Usually, the chemicals are present in the form of mixed chemical compounds so, their cumulative effects on sediment are difficult to anticipate [21]. Aquatic ecosystems must be investigated in a holistic and integrated manner for water and sediment quality assessment. The goal is to integrate several lines of investigation, in which all heterogeneous factors are considered to be evaluated (e.g, physical and chemical characterization of the habitat, biological surveys, ecotoxicological tests) by applying interspersed approaches [22].

This study aimed at assessing the water and sediment quality of the Midia Port using some specific physical-chemical and biological criterions. The results will constitute a reference for the current Situation and a baseline for future monitoring, tracking changes and trends over time in the water/sediment quality as a result of the anthropogenic activities on the port environment. The overall Performance achieved within this study will be presented within some limitations, being unable to cover the wide range of all anthropogenic Stressors that might affect the Midia Port environment. Here, we specify the difficulty of surely predicting changes due to anthropogenic activities, the lack of relevant historical data on water and sediment quality, Information gaps on the impact of the port operations on specific marine characteristics.

2 Study area and the environmental setting

The Midia Port is positioned at a major point of the Romanian coastal area (e.g, Cape Midia), at the junction between the northern and southern units of the Romanian Black Sea coastline (see Figure 1 a). The Midia Harbor is situated between the Northern Unit, a part of the Danube Delta Biosphere Reserve (an area around 6,000 km2), and the Southern Unit, which is strongly influenced by the human activities. Romania’s smaller Port of Midia is situated on the Black Sea coastline about 25 km north of Constanta Port (see Figure 1 a). It is one of the satellite ports of Constanta envisaged to ensure the various adjacent industrial and petrochemical facilities. The port was founded in the middle of the XXth Century, and its infrastructure was extended during the late 70’s, aiming to become one of the major commercial sea terminals for hydrocarbons along the Black Sea coastline. For a relatively long period, it has played an important role regarding the commercial activity in the area. Since the 90’s has gone through a period of low activity. Now, serves as petroleum and general merchandising terminals. To the north and south, the Midia Port is bordered by breakwaters, having a total length of 6.97 km (see Figure 1 b). The harbour Covers a total surface of 834 ha, of which 234 ha is represented by land, and 600 ha by water. Within the port, there are 14 berths (e.g., 11 operational and the other 3 belong to Constanta Shipyard), with a total length of 2.24 km.

Figure 1 The aerial image ofthe Romanian Black Sea coastal area, includingthe Midia Port location (a), and an image showingthe Midia Port zone (b), (Source images:On line at: http://www.google.com/earth/index/html.On line at: http://www.portofconstantza.com with addings and with some modifications
Figure 1

The aerial image ofthe Romanian Black Sea coastal area, includingthe Midia Port location (a), and an image showingthe Midia Port zone (b), (Source images:[2][3] with addings and with some modifications

The investigated area may be subjected to environmental disequilibrium. The possible polluting effects are not caused only by the industrial activities that occur in the Midia Port area, but also they can appear as a result of the Danube River impact upon the northwestern Black Sea environments. The marine pollution by hydrocarbons represents an alarming phenomenon, which has taken unprecedented amplitude since many years ago. Into the Black Sea are downloaded annually about 110.000 tonnes of oil, making the effects of pollution to manifest in the environmental balance of the entire basin. A high propor-tion of pollution to the marine environment comes through the Danube River (e.g., discharging a quantity of 53.000 tonnes of oil, annually), domestic sewages (e.g., 30.000 tonnes of oil), industrial wastewaters, oil industry (e.g, 15.000 tonnes of oil) and maritime transport (e.g, 12.000 tonnes of oil), [23]. Although during the recent decades, it has been noticed a decreasing trend of the Danube River sediment input (e.g, due to hydro-technical works along the Danube River and its distributaries), the Danube River is still carrying a considerable amounts of Sediments to-wards the Black Sea [24]. The Black Sea coastal area can be separated into two units: the northern unit situated in front of the Danube Delta, and the southern one, placed from the Mamaia Bay up to the Bulgarian border [25]. The two units are delimited by the Cape Midia, considered as an “impermeable limit” in the sediment circulation, as a result of the Midia Port breakwaters (see Figure 1 b). These structures have restricted the accumulation of Sediments derived from the Danube River, interrupting the longshore coastal transfer from north to south [26]. In the southern part of the Danube Delta coast, the environmental protection works (e.g, port defence, beach restoration, artificial pocket beach constructions) from the port area and the coastal zones have a considerable influence on the coastal current rates and directions [27]. As regards the Black Sea, this is one of the world’s enclosed seas, covering an area of about 4.2 x 105 km2; the maximum water depth reaches 2.212 m, and the total volume of seawater is 534.000 km3. The entire lower layer of the seawater (e.g, approximately 423.000 km3 below a depth of 150-200 m) is anoxic and contains large amounts of hydrogen sulphides. The water salinity is around 17%oat the surface, and 22%0at the bottom, decreasing up to 10-12%0in the Danube Delta front surroundings [28]. The unique hydrological and hydro chemical characteristics of the Black Sea confer the Status of the largest anoxic basin in the world. The Black Sea is subject to environmental variations due to the natural influences (e.g, climate change, global warming, sea level rising, coastal erosion), and also due to the anthropogenic factors (e.g, air, water and sediment pollution); during the last period, a State of worsening in the ecological capacity of the sea has been remarked [29]

Generally, the entire coastal area that includes the Midia Port is supplied with the Danube River alluvial sediment remobilized from north to south, through the littoral longshore current. The Danube River flows into the Black Sea through three principal arms (e.g, Chilia, Sulina and Sf. Gheorghe). The average water flow discharge of the Danube River is 6.300 m3/s [30]. The distribution of the water discharge relating to the three main branches is: Chilia 58%, Sulina 19%, and Sf. Gheorghe 23% [31]. The hydro technical works, performed along the Danube River and its branches, including the Danube Delta, too, have considerably changed the water flow and the sediment discharge, and consequently, the particle flux distribution in the northwestern Black Sea. Under these circumstances, the sediment discharge has decreased by approximately 30-40%, and presently, the Danube average total sediment discharge into the Black Sea does not exceed 35-40 million tonnes/year, from which 4-6 million tonnes/year are sandy materials [24, 32]. This is the only source of sandy sedi-ments that supply annually the littoral sediment budget, which has become quite imbalanced since the 70’s [28]. Midia Port receives two types of waters from two major sources: the Danube River freshwaters, Coming from the Danube-Black Sea Canal - at Navodari Lock, (see Figure 1 b), as well as the brackish Black Sea waters. The investigated perimeter may be the subject of the different chemical components brought by the Danube River fluvial input (e.g., influenced by the human activities in the upstream Danube watershed), as well as from the Black Sea environment.

3 Materials and methods

Samplingand sample preparation- The water and sedi-ment survey field, as well as laboratory methods, are decisive parts of this study whereabouts environmental quality assessment was considered by using GPS coordinates, field measurements and laboratory analysis.

An array of water and sediment samples were collected during two sampling campaigns, carried out in 2011 (24 samples) and 2012 (10 samples), (see Figure 2).

Figure 2 Sampling locations, including the informal delimitation of the investigated sectors in the Midia Port area based on port-related activities (Source image:On line at: http://www.aries-shipping.ro, with addings and modifications).
Figure 2

Sampling locations, including the informal delimitation of the investigated sectors in the Midia Port area based on port-related activities (Source image:[4], with addings and modifications).

The sampling stations have been chosen in relation to the sectors where the various port’s-related activities take place within the port area. In this sense an informal partition of some particular sectors has been performed according to the activities carried out in the port zone: The Cargo Terminal Area(e.g., general merchandise, shipyard), The Oil Terminal Enclosure Area(e.g., refining activities), The Ships Transit Area(e.g, shipping activities and working operations), The Waste Oil Buffer Area(e.g, a local point source of residual flow), and The Marine Area(e.g, shipping activities around the port), (see Figure 2).

The preliminary field observations, including various in situ measurements, as well as the sub-sampling procedures for laboratory analyses performed on water and Sediment samples were accomplished aboard the “Istros” Research Vessel (belonging to The National Institute of Marine Geology and Geoecology-GeoEcoMar, Romania).

The surface water samples were collected in a bücket in every Station, aiming to serve for in situ measurements and subsequent laboratory analysis (e.g, nutrients, heavy metals, organic compounds, microbiology and ecotoxicology). All the recipients were previously washed with a 5% hydrochloric acid solution and rinsed in distilled water.

The surface sediment samples from within the upper the 0-20 cm, were gathered for physical-chemical analysis and toxicity bioassays. The sediment sampling was performed using a Van Veen-type grab sampler, as well as a simple gravity corer. Then, the sub-samples were transferred in proper Containers (plastic boxes and glass jars).

The collectors with water and sediment samples were treated according to the protocol (e.g, labelled, covered with aluminium foil, placed in plastic bags and stored in cold conditions, at 0-4°C), until their delivery to different laboratories from Romania and Italy, for various analyses.

Reactants and Equipments- The present study has been prepared in the framework of the international project entitled SEDI. PORT. SIL (additional Information is available[5]). The analyses were performed in specialized laboratories in Romania (GeoEcoMar Institute) and Italy (CRSA-ISPRA-Med-IngegneriaS.r.l.).

All the reactants used in the analytical experiments were of high purity. The preparation of the Solutions was performed using very pure water (0.05 μS/cm).

The water physical-chemical parameters were mea-sured by the WTW Multiline P4 Multiparameter (e.g, dissolved oxygen, temperature, electrical conductivity, total dissolved salts, pH, redox potential) and HACH 5000-UV-Vis - Spectrophotometer (e.g, nitrates, nitrites, phosphates, sulfates), aboard the “Istros” Research Vessel-chemical laboratory. The turbidity was measured by the HACH 2100Q Portable Turbidimeter. The identification of the total amounts of organic compounds and heavy metals in water and Sediments was performed in Italy (CRSA-ISPRA-Med-Ingegneria S.r.l.). The heavy metals analysis was completed by inductively coupled plasma optical emission spectrometry (e.g., ICP-MS, Thermo-Scientific); the lighter organic compounds, as VOC’s and BTEX’s, were detected by GC-MS (e.g., Thermo-Scientific) with automatic extraction equipment. Oil and grease, as well as the Total Hydrocarbons (TH) concentration, were identified by gas chromatography, coupled by Flame Ionization Detector (e.g., GC-FID, Perkin Eimer). The percentage distribution of the main lithological components (e.g, total organic matter, carbonates and siliciclastic fraction) was conducted by SNOL 8.2/1100°C (high-temperature electric furnaces). The mineralogy and grain size distribution was performed by classic mineralogical techniques and respectively by the sieving method combined with the pipetting method. Microbiological susceptibility was tested in Fecal Enterococci, Escherichia coli, Sulphite reducing clostridia, Salmonella spp., Yeast and fungi. The ecotoxicological tests were performed on the Vibrio fischeri(e.g, light emission inhibition), Brachionus plicatilis(e.g, hatching of the cysts) and Phaeodactylum tricornutum(e.g, inhibition of the algal growth).

Procedures of Analyses- All sampling and laboratory protocols have been rigorously fulfilled to not contaminate the water and sediment samples.

Water- In the course of two sampling campaigns, a number of 22 water surface samples were analyzed. The measurement of the dissolved oxygen, temperature, electrical conductivity, total dissolved salts, pH, redox potential were performed in situ by direct immersion of a Special measuring Multi-Probe System (glass electrodes). The determinations of nitrate, nitrite, orthophosphate and sulphate levels (mg/1) in water samples were performed in less than 24 hours after the sampling; the water samples were filtered before analyzing. A colorimetric method using HACH DR/5000 model spectrophotometer was used. According to the protocols[6], the following methods were used: the Cadmium Reduction Method-Hach Method 8192 (nitrate concentration/0-0.40 mg/1NO3), the Diazotization Method-Hach Method 8507 (nitrite concentration/0-0.300 mg/1NO2), the PhosVer 3-Ascorbic Acid, Method-Hach Method 8048 (orthophosphate concentration/0-2.500 mg/1PO43) and the SulfaVer 4 Method - Hach Method 8051 (sulphate concentration/0-70 mg/1 SO42). The ICP-MS determinations of heavy metal concentrations expressed in μg/1 (e.g, AI, As, B, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sb, V and Zn) were conducted in surface water samples. Other inorganic determinations in seawater samples (e.g, free cyanide, fluoride, sulphur, sulphite, anionic surfactants, non-ionic surfactants), were executed spectrophotometrically, except for anions by ionic chromatography[7]. The identification and quantification of the aromatic hydrocarbons (BTEX’s) and other organic compounds were carried out in conformity with Standards[8]. The microbiological analysis takes into consideration the growth of Escherichia coli as the commonly used fecal indicator organism bacteria[9], the determination being performed by sample filtration and incubation on selective culture medium (at 44°C). The ecotoxicological assessment of water samples was completed using the bioluminescent bacteria test with Vibrio fischeri(the maximum effect % of the light emission inhibition), by AZUR Environmental instrument, accordingly with the protocols[10].

Sediment- The surface (0-20 cm) bottom sediment samples were collected inside and outside the port area during 2011 and 2012 (including core sediment, too). As regards to preliminary sediment preparation, the used pretreatment methods have included fractionation, homogenization, compositing, Splitting and the selection of a specific scale of particle size for different analysis. In the laboratory, the sediment samples were heated in a drying stove at 105°C, to remove their water content and reach a constant mass necessary for further determinations. The water content was determined by drying the sediment to constant mass and then measuring the sediment sample mass before and after drying. The water content represents the differences between the masses of the raw (wet) and dry sediment. The typical drying temperature is set at 105°C (100°C-110°C) being established in function of the boiling temperature of water, disregarding the physical and chemical sediment characteristics [33]. The measurement of particle size was performed using the sieve-pipette Standard method [34]. Prior to sieving the sediment samples were washed with distilled water in a 0,063 mm sieve and the fine material passed directly into glass cylinders. For the sieving method, it was used a set of sieves with con-figured mesh diameters varying between 0,063 and 2, 000 mm. The Separation of the sand fraction was executed by vibrating the sieves over a 15-minute period followed by weighing. The pipetting was accomplished with a 1-liter capacity cylinders and a 50 ml pipette. The percentages were estimated by combining the values of each fraction obtained through the two techniques. The particle size analysis results are in accordance with the Wentworth dimensional scale [35], and the sediment distribution was performed in conformity with the Shepard’s diagram [36]. The percentage distribution of the main lithological components (organic matter, carbonates and siliciclastic fraction) in superficial Sediments was done by theLoss on Ignition Method [37, 38]. The method is based on the sequential heating of the sediment samples using high-temperature electric furnaces SNOL 8.2/1100°C. The raw sediment samples are precisely weighed, dried at 105°C (to remove all free water), re-weighed, and then heated at 550°C (the organic matter is oxidized to carbon dioxide and ash), re-weighed again, and finally heated at 950°C (the carbon dioxide is released from carbonate, leaving the oxides). The mineralogical characteristics were performed in reference to the microscopic mineralogical determination guide [39]. The sediment samples were sieved, followed by the extraction of the arenitic granoclasts - fine and very fine sand (e.g., class 0.250-0.063 mm). The carbonates and silici-clasts along with oxides and sulfides contents of the selected arenitic class were estimated from the data resulted by weighing the samples, before and after the removal of the carbonate by treatment with hydrochloric acid (16% concentration). The bromoform (density 2.9 g/cm[3]) was used to separate the decarbonated granoclasts, generally silici-clasts, and have been deferentially investigated, on heavy and respectively light subfractions [40]. The hydrocarbons (C>12) expressed as min-eral oils, polycyclic aromatic hydrocarbons (PAH’s) and polychlorinated biphenyl (PCB’s) were detected by Perkin-Elmer gas-chromatograph, conform to Standards[11][12]. The acid digestion of sediment samples, prior to analyses by ICP-MS, was necessary for the majority of heavy metals. The ICP-MS determinations of the heavy metals, expressed in mg/kg (e.g., As, Ba, Cd, Cr, Cu, Fe (%), Hg, Mn, Ni, Pb, Zn) were investigated in recently deposited sediment samples, accordingly to procedures[13]. The analysis of the light organic compounds in Sediments as, the aromatic hydrocarbons (BTEX’s), volatile hydrocarbons (VOC’s), aliphatic chlorinated carcinogenic/non-carcinogenic organics and aliphatic halogenated carcinogenic hydrocarbons, were detected by the purge and trap extraction of the sediment accordingly with normative[14]. The microbiological quality of Sediments was assessed by: Fecal Enterococci, Escherichia coli, Sulphite-reducing clostridia, Salmonella spp., Yeast andfungi, resorting to Standard methods[15][16]-Line D and Line E), aliphatic halogenated hydrocarbons (see [15][17][18][19]. The ecotoxicity of sediment samples were evaluated employing the test organisms as Vibrio fischeri (e.g., light emission inhibition on the whole sediment), Brachionus plicatilis(e.g., hatching of the cysts on 1:4 water extrac-tion) andPhaeodactillum tricornutum(e.g., inhibition of al-gal growth on 1:4 water extraction), applying the Standard methods[20][21][22].

4 Results and discussion

The water and sediment quality analysis performed in this study has been used to identify the factors influencing the environmental quality and to establish if the samples in question are within the acceptable environmental Standards. The assessment of the results was related to the Romanian and Italian environmental Standards for water and sediment quality.

Water analyses- A synthesis of the physical, chemical and biological properties of the surface water samples is presented hereinafter. The results of the physical-chemical parameters registered during field campaigns were compared to the normative available at the national level[23], and are included in the Table 1-Line A. The physical-chemical parameters varied among stations. Sea-water quality is not constant, fluctuating with the temper-ature, time of the day, season, weather conditions, water sources, coastal and sedimentological characteristics etc. A close examination of the results exposes different trends that are discussed below:

Table 1

Summary of the physical, chemical and biological indicators investigated on the Midia Port surface water samples.

Line APhysical-chemical Parameters; (n=22)
ValuesO2(mg/l)O2 (%)T°CCND(mS/cm)TDS (mg/l)EH(mV)Turbidity (NTU)pH
Min7.2284.796.564.41352.527.71
Max14.86186.126.826.417.6915810.89.26
Mean9.5±1.64110.0±20.0419.18±6.2723.31± 4.4715.62±3.00143.8±7.874.73±2.658.28± 0.27
ValuesSS (mg/l)Sal (‰)N-NO3 (mg/l)N-NO2(mg/l)PO43SO42(mg/l)SS (mg/l)Sal (‰)
Min13.60.010.0030.0121513.6
Max10216.20.040.0130.556510216.2
Mean11.45±20.5414.01±2.830.020±0.0080.008±0.0030.077±0.10401.3±95.5411.45±20.5414.01±2.83
Line BHeavy metals content (jug/l); (n=13)
ValuesAISbAsB CdCr (total)Cx(Vl)Fe
Min3.20.542.75320.550.520
Max6.91.361.116980.550.520
Mean4.9±0.90.6±0.356.±4.51474.5±324.30.550.520
ValuesHgMnNiPbCuSeNaVZn
Min0.1511100612800.330
Max0.751.81.91002336753.930
Mean0.2±0.251.5±0.31.2±0.310014.9±4.82938.8±725.10.7±1.030
Line CInorganic compounds content; (n=13)
ValuesFree Cyanide (μg/l)Fluoride (mg/l)Sulphate (mg/l)Sulphur (as H2S) (mg/l)Sulphite (as SO3) (mg/l)Anionics Surfactants (MBAS) (mg/l)Non ionic surfactants (BIAS) (mg/l)
Min131503620.010.110.1
Max4036012160.863.81.50.2
Mean24.7±7.0175.4±62.01008±232.990.65±0.291.4±1.51.1±0.10.1
Line DOrganic compounds content (mg/l); (n=13)
ValuesGrease and oilsMineral Oil (C10-C40)Phenol totalAldehydesNitrogenous organic solventsPhosphorus pesticidesTotal pesticides (except phosphorus)Chlorinated Solvents
Min0.090.070.20.10.10.10.10.1
Max0.250.210.92.10.10.10.10.1
Mean0.16±0.050.13±0.040.7±0.203±0.60.10.10.10.1
Line EMicrobiological analysis (n/100 ml); (n=13)Ecotoxicological analysis (maxim effect %); (n=13)
ValuesEscherichia coliVibrio fischeri
Min10-24.8
Max7225
Mean25.77±24.2810.58±19.38

The oxygen regime- Generally, the levels of the dis-solved oxygen throughout all the sampling stations lie within the Standard stipulated by the environmental legislation. The dissolved oxygen concentration varied from 7.22 to 10.96 mg/1; the concentration of dissolved oxygen Saturation fluctuates from 84.7 to 120.2%. An exception of this trend is related to the sample MDA 11-17, collected from The waste Oil Buffer Area, an area containing a local point source of residual flow (see Figure 2, for sample site), that shows the highest concentration of oxygen, e.g, 14.86 mg/1. Such inconsistencies may be common in the restricted marine waters, where the effects of discharges in fluctuation of dissolved oxygen mostly depend on many factors as the degree of water movement, the dominant drainage course, the volume of mixing, submerged aquatic Vegetation etc.

The regime acidification(pH) - The majority of the pH results was found in the domain of most natural waters that falls in the 6 to 8.5 range [41]. The pH was found to have slight variations between stations corresponding to an interval between 7.71-8.50, excepting, one water sample (MDA 11-17), that records a pH value of 9.26. Otherwise, there were not registered lower or higher pH values. Generally, it can be said that the Midia Port water pH presents a very slightly alkaline character, not indicating the exis-tence of eloquent sources of acidic or alkaline compounds in the investigated area.

The salinity regime (the electrical conductivity - EC; sulfates) - The values of electro-conductivity are quite high, as compared to water quality Standard, varying from 18.72 to 26.4 ms/cm, excepting the same sample, MDA 11-17, for which the EC has a low value of 6.56 ms/cm. An explanation for the EC high values could be the fact that the measurement was performed in a mixture of waters (the higher density of the brackish water insufficiently combined with the freshwater), which is also certified by the fluctuating values of salinity; the salt water incorporates an indisputable amount of salts, which confer a higher conductivity to the water. The sulphates remark values above the maximum allowable limits, ranging from 300 mg/1 to 565 mg/1, with the exception of the sample MDA 11-17 (215 mg/1).

The high sulphate content identified in this sector is most likely due to the industrial wastes, Coming from the Midia port-related activities. In the investigated samples, the values measured for the salinity fluctuate from 10.8 to 16.2%.

The turbidity regime- The turbidity measurements performed in 2012 show some values exceeding the current regulations, as for example the samples MDA 12-30 (5.12 NTU), MDA 12-32 (6.94 NTU) and MDA 12-34 (10.8 NTU). These sampling stations are located in areas with intense port-related activities (see the location of the sampling sites in Figure 2). Another possible cause of high turbidity levels in these investigated waters may be due to the re-suspended Sediments (dissolved organic matter or in-organic particles) from the bottom of the harbour caused by the movement of vessels inside the port.

The nutrient regime- The N-NO3, N-NO2 and the PO43 concentrations, also agreed, for the most sampling sites with the environmental Standards. No exceedances were recorded for these chemical parameters in any water samples. The fluctuation range of the nitrates (N-N03) is between 0.01-0.04 mg/1, for nitrites (N-N02) is comprised between 0.003-0.013 mg/1, and for orthophosphates (PO43), fluctuates within 0.01-0.50 mg/1. The acquired results did not show any potential sources that may advance the accumulation and intensification of the nutrients in the investigated area.

The heavy metals content- The surface water samples were investigated for: AI, As, B, Cd, Cr, Cu, Fe, Hg, Mn, Na, Ni, Pb, Sb, Se, V and Z, to figure, if possible a correlation between the levels of heavy metals and water contamination.

Generally, all the analysed water samples, investigated for the heavy metal concentration, show values that are situated below the maximum allowable limits. A summary of the heavy metals content is shown in Table 1-Line B. The relative uniformity of the results does not suggest the existence of any unregulated discharges from point or diffuse sources containing high concentrations of heavy metals. Although there is an intense port-related activity, there is no evidence of strong heavy metal contamination of waters. However, some exceptions are given by As, B and Se that show very high values, found in most investigated samples. For As, exchangeable levels in most samples with the mean values of 56.7±4.5 μg/1, were found to exceed the recommended limit, which is 10μg/1. All of the exchangeable concentrations encountered for B, with the mean values of 1474.5±324.5μg/1, were above the maximum recommended which is 1000 μg/1. High levels of Se, with the mean values of 14.9±4.8μg/1, exceed the recommended limit that is 10 μg/1. The presence of these elements in higher concentrations may be due to the intensive human activities (past or current), which involve operations with various compounds Coming from chemicals, petroleum products, fertilizers, scrap metals, electronic wastes, industrial wastes, shipyards etc.

The inorganic compounds content- The level of free cyanide, fluoride, sulphur, sulphite, anionic and non-ionic surfactant concentrations also agreed for most investigated samples, with the environmental Standards. The results are presented in Table 1-Line C. Instead, the sulphates analyses show higher values, ranging from 1003 to 1216 mg/1 (with the mean values of 1008±232.9 mg/1), in contrast to regulation limits, which is 1000 mg/1.

The organic compounds content- The recorded data show that the concentrations of the aromatic hydrocarbons-BTEX’s, grease and oils, mineral oils, phenol total, aldehydes, nitrogenous organic solvents, phosphorus pesticides, chlorinated solvents, etc., identified in the investigated water samples, do not present higher levels in comparison with the maximum allowable concentrations set by the regulation limits. The acquired results are shown in Table 1-Line D.

Biological testing- The microbiological tests were performed to identify the level of the microbial content in water. The microbiological examination of water samples was performed by using the Escherichia coli bacteria as the principal indicator organism. The ecotoxicological analyses were used to identify the harmful effects of the potential toxic contaminants. The toxicity of the water samples was tested with the bioluminescence inhibition of the Vibrio fischeri bacteria and the results show a slight toxicity effect in some samples, even if it was less than 50% (anyway, EC-half maximal effective concentration-50% values were not detectable). So, the microbiological and ecotoxicological tests performed for water samples do not reveal significant overruns for the investigated parameters. The results are presented in Table 1-Line E. The microbiological alterations in water may be as a result of the inadequate water filtration and purification Systems of vessels, or eise, due to accidental spills occurred during the different ship operations and repairing works.

The results of the water samples investigations indicate a satisfactory water quality of the Midia Port aquatory in relation to the different physical-chemical and biological parameters, despite the local development in terms of port activities and port-related industrial activity. The investigated water samples correspond to a normal environmental quality Status[23]. Based on Visual field observations, it can be appreciated that the port waters can sustain the aquatic life. However, it has been revealed an anomalous water sample (MDA 11-17), collected during the year 2011 that present inconsistencies, relating to the regulations. These anomalies may be due to The Waste Oil Buffer Area, an area containing a local point source of residual flow, (see Figure 2). It is worth mentioning that the analysis of the water samples presents a temporary perspective of the port environmental condition. For example, most trace metals, do not exist in soluble forms for a long period in water, therefore the results should be correlated with other morphological and chemical sediment parameters [[23]], to obtain an arguing assessment on water pollution caused by trace elements.

Sediment analyses- This sediment quality analyses goal was to identify if the specific indicators are in accordance with reference Standards at the sampling sites, as well as the identification of potential anthropogenic Stressors. This approach is intended to assess the sediment condition related to potential for exposure to contaminants in Sediments. The exposure to contaminants at risk levels causes an evident increment concentration of contaminants in sediment. The whole range of specific indicators was considered to figure the sampling stations level assessment. The results will be transposed through terms of assessing the degree of impact. The assessment category indicates the magnitude and extent of contaminated Sediment, investigated at each sampling Station.

Structural and textural characterisation ofthe sediments- A short characterisation ofthe sediment samples in terms of structural and textural aspects applied to surficial Sediments will be presented, further on.

Grain-size- The surface Sediments within the Midia Port and the explored surrounding zones are characterized by the predominance ofthe sand (particle size > 0.063 mm), followed by silt (diameter varying between 0.063-0.004 mm), and small amounts of clay (diameter < 0.004 mm). According to the Shepard’s diagram, the most sediment belongs to the specific category of “silty sand”, followed by “sand”, “sandy silt” and “clayey silt”. The investigated sediment samples contain also fine particles, probably, accumulated due to the suspended Sediments.

Relating to the sectors of investigations, delimited in the Midia Port area (see [22]), we report the grainsize categories, as follows ([21]):

Figure 3 The distribution of the grain-size categories considered for the surficial sediments collected from the Midia Port area (Source image:APAT CNR IRSA Man 29 2003., with some addings and modifications). Note: For a better understanding regarding the horizontal distribution, an empirical representation of the grain-size areal variation is delineated above. The colors have been chosen aleatory.
Figure 3

The distribution of the grain-size categories considered for the surficial sediments collected from the Midia Port area (Source image:[20], with some addings and modifications). Note: For a better understanding regarding the horizontal distribution, an empirical representation of the grain-size areal variation is delineated above. The colors have been chosen aleatory.

  1. The Cargo Terminal Area - an association of different group types, including “sandy silt”, “silty sand” and “clayey silt”;

  2. The Oil Terminal Enclosure Area - a mixture of various group types, for example, “silty sand” and “sandy silt”;

  3. The Ships Transit Area - a combination of distinctive group types, of which some are represented by “silty sand”, “sandy silt” and “clayey silt”;

  4. The Waste Oil Buffer Area - a group type such as “silty sand”;

  5. The Marine Area - an assemblage of different group types, as “sand”, “sandy silt” and “silty sand”.

Bottom organic matter- Aiming the estimation of the organic content, as debris of plants and organisms, that are good adsorbents of heavy metals and organic pollutants too, and relating it to adsorptive capacity, the port sediment samples were analyzed for the percentage distribution of the main lithological components (total organic matter, total carbonates and siliciclastic fraction). Referring to the total organic matter, content, expressed as the weight percentage, a “mineral sediment” group was distinguished; the investigated sediment samples having values between 5 to 53 wt% (with an average of 29.70±17.64) of organic matter content. The carbonate content varies from 1.41 to 5.65 wt% (with an average of 3.88±1.05). In this respect, the investigated sediment samples couldbe categorized as “calcareous” having more than 1 wt% carbonate content. The minerogenic clastic fraction show values between 13.03 to 88.82 wt% (with an average of 66.42±16.66).

Mineralogy- The mineralogical composition of the Midia Port superficial Sediments is rather heterogeneous and concerns a large spectrum of mineral species. Overall, the dominant aspect of quartz in the detritus fraction spectrum was noticed. The heavy minerals are present in a small percentage in the detritus fraction and vary around 1% in the sand fraction. The mineralogical analysis reveals that the sandy fraction ofthe Sediments is mainly occupied by quartz (77-88%), followed by feldspar (7-14%), mica minerals (1-12%), chlorite (0.5-7%), heavy minerals (0.02-1%) etc. The aspect of grains and the grainsize, including the heavy minerals too, presume the predominant eolian origin for most of the sediment particles within the perimeter.

Sediment chemistry- The survey ofthe sediment pollutants and the evaluation of the sediment quality are mainly performed to show if the Sediments represent either a source or a sink for contaminants, and subsequently, to estimate the contaminating effects upon the aquatic environmental System [[19]]. The investigation of the distribution of the heavy metals and organic compounds within the sediment samples aims to explain their dispersion associated with the natural inputs (geological background), and with the anthropogenic activities (e.g., industrial and agricultural works, including also port activities and port-related industrial activity). Sediment chemistry refers to the measurement ofthe concentrations of chemicals of concern in Sediments.

Concentration and distribution of organic compounds- The superficial sediment samples were assessed for many organic compounds (e.g., aromatic hydrocarbons-BTEX’s, total volatile hydrocarbons-VOC’s, aliphatic chlorinated carcinogenic/non-carcinogenic organics, aliphatic halogenated carcinogenic hydrocarbons, hydrocarbons-C > 12, expressed as mineral oils, poly-cyclic aromatic hydrocarbons-PAH’s and polychlorinated biphenyl-PCB’s.

In general, the differences in the concentration related to the distribution of the organic compounds performed between different sediment samples were not so elevated, although in some cases the increased concentrations were established.

In this respect, the majority of the sediment samples investigated for aromatic hydrocarbons-BTEX’s (see [18]-Line A), total volatile hydrocarbons-VOC’s (see [17]-Line B), aliphatic chlorinated carcinogenic/non-carcinogenic organics (see [16]-Line D and Line E), aliphatic halogenated hydrocarbons (see [15]-Line F) were below the recommended limit stipulated by the environmental standards.

Table 2

Summary of the organic compounds indicators probed on the Midia Port sediment samples.

Line AAromatic Hydrocarbons (BTEX’s) (mg/kg); (n=24)
ValuesBenzeneEthylbenzeneStyreneTolueneXylene
Min0.010.010.010.010.01
Max0.010.010.010.010.15
Mean0.010.010.010.010.02
Line BVolatile Hydrocarbons (VOC’s) (mg/kg); (n=24)Line CHydrocarbons C=12 (mg/kg); (n=24)
ValuesTotal Volatile Hydrocarbons (C<12)Values(expressed as mineral oils)
Min1Min20
Max197Max12083
Mean15.79±50Mean671±2463.121
Line DAliphatic Chlorinated carcinogenic Organics (mg/kg); (n=24)
ValuesChloromethaneDichloromethaneTrichloromethaneVinylchloride1,2 Dichloroethane1,1–DichloroetihyleneTrichloroethyleneTetrachloroethylene (PCE)
Min0.010.010.010.010.010.010.010.01
Max0.010.010.010.010.010.010.010.01
Mean0.010.010.010.010.010.010.010.01
Line EAliphatic Chlorinated non carcinogenic Organics (mg/kg); (n=24)
Values1,1 –Dichloroethane1,2 –Dichloroethylene1,1,1 Trichloroethane1,2 Dichloropropane1,1,2 Trichloroethane1,2,3 Trichloropropane1,1,2,2 Tetrachloroethane
Min0.010.010.010.010.010.010.01
Max0.010.010.010.010.010.010.01
Mean0.010.010.010.010.010.010.01
Line FAliphatic halogenated carcinogenic Hydrocarbons (mg/kg); (n=24)
ValuesTribromomethane1,2 DibromoethaneDibromochloromethaneBromodichloromethane
Min0.010.010.010.01
Max0.010.010.010.01
Mean0.010.010.010.01
Line GPAHs (ng/gss); (n=24)
ValuesNaftaleneAcenafteneFluoreneFenan-treneAntraceneFluorantenePireneBenzo (a) antracene
Min0.50.51.537.770.50.50.50.5
Max66.6970.92435.474506.75249.74606.45467.06738.59
Mean14.49±15.825.90±14.2529.32±89.77280.52±928.3521.34±56.8288.55±136.87341.24±1125.6465.03±167.85
ValuesCriseneBenzo(b)- fluoranteneBenzo(k)- fluoranteneBenzo (a)pireneDibenzo (a,h) antraceneBenzo(g,h,i) perileneIndeno (1,2,3,c,d)pireneƩPAH tot
Min1.851.850.50.770.560.890.9618.75
Max1314.79908.18108.5339883.12323.46175.9515441.88
Mean129.60±339.9191.95±200.4221.50±29.7357.66±106.836.09±16.8835.51± 66.7825.17± 39.081213.65±3254.67
Line HPCBs (ng/gss); (n=24)
ValuesPCB 28PCB 52PCB 101PCB 81PCB 77PCB 123PCB 118PCB 114PCB 153PCB 105PCB 138
Min0.050.090.080.10.10.080.070.10.090.080.06
Max0.751.083.850.10.10.130.960.115.32.919.23
Mean0.20±0.160.26±0.231.04±1.180.10.10.10±0.010.23±0.200.12.64±3.400.45±0.631.72±2.13
ValuesPCB 126PCB 128PCB 167PCB 156PCB 157PCB 180PCB 170PCB 169PCB 189PCB 209Ʃ PCB tot
Min0.10.080.060.050.050.10.060.10.070.050.28
Max0.11.440.271.350.1114.146.030.10.310.1256.79
Mean0.10.26±0.300.11±0.040.20±0.260.10±0.012.37±3.180.96±1.310.10.12±0.060.09±0.0210.72±13.01

Instead, the hydrocarbons (C>12) expressed as mineral oils (see [14]-Line C), presents higher values in two samples collected from the Waste Oil Buffer Area, namely, MDA11-17 (12083 mg/kg) and respectively, MDA11-18 (1974 mg/kg), in contrast to regulation limits which is 50 mg/kg (for sampling site location, see [13]). Probably, these exceedances may be associated with the accidental oil spills from the petrochemical complex (Petromidia Refinery). In other probed sediment samples exchangeable concentrations of hydrocarbons (expressed as mineral oils) -C>12, were encountered to be very close, relatively close or above to the environmental standards.

The polychlorobiphenyls-PCB’s and the polycyclic aromatic hydrocarbons-PAH’s compounds, which are mainly produced by the industrial activity, also represent a great environmental risk.

The PCB’s are still widely used in the industry (e.g., manufacture of transformers, capacitors, paints, plastics, foils, inks etc.). The PAH’s are formed by the incomplete combustion of the organic materials in various industries (e.g., steel or aluminium factories, asphalt, tar preparation stations, and petroleum refineries). For the majority of the investigated sediment samples, the contents of the PAH’s and PCB’s overrun the maximum content level shown by the regulations. The summary of results is shown in [12]-Line G and Line H.

The majority of sediment samples collected from the bottom of the harbour revealed levels of PAH’s, which are higher than the maximum allowed by environmental legislation. For some specific organic compounds, the exchangeable concentrations were found to be above the stipulations, as follows: pirene(mean values of 341.24±1125.64 ng /g compared to recommendation which is 5 ng/g), benzo(a) antracene(mean values of 65.03±167.85 ng/g, opposed to recommendation, which is 0.5 ng/g), crisene(mean values of 129.60±339.91 ng/g, contrasting to recommendation, which is 0.1 ng/g), benzo (b) fluorantene(mean values of 91.95±200.42 ng/g, opposed to recommendation, which is 0.04 ng/g), benzo (k) fluorantene(mean values of 21.50±29.73 ng/g, compared to recommendation, which is 0.02 ng/g), benzo (a) pirene(mean values of 57.66±106.83 ng/g versus recommendation, which is 0.03 ng/g), dibenzo (a,h) antracene(mean values of 6.9±16.88 ng/g, in contrast to recommendation, which is 0.1 ng/g), benzo (g,h,i) perilene(mean values of 35.51±66.78 ng/g, opposing to recommendation, which is 0.05 ng/g), indeno (l,2,3,c,d) pirene(mean values of 21.17±39.08 ng/g, versus recommendation, which is 0.07 ng/g), and ∑ PAH tot (mean values of 1213.65±3254.67 ng/g, compared to recommendation, which is 0.2 ng/g).

The higher values were encountered in areas significantly impacted by the port-related activities as The Cargo Terminal Area, The Oil Terminal Enclosure Area, The Ships Transit Area and The Oil Buffer Area(see [11]).

The same tendency is also valid for the PCB’s levels in measured samples, with troubling values that are above the allowable content established by the regulations. High levels of ∑ PCB tot, with the mean values of 10.72±13.01 ng/g, exceed the recommended limit that is 0.004 ng/g.

The obtained results show high contamination levels for PAH’s and PCB’s in sediment samples of the Midia Port Area. So, the sediments have been assessed as “low” quality status. In this context, the fact that a large number of samples were identified as being contaminated with PAH’s and PCB’s leads to the idea of a historical pollution in the area. Their distribution in the marine environment is mainly due to industrial activities through wastewater discharges, from oil refining industries, accidental oil spills and leakages, shipping activity and maneuvering operations or atmospheric transport.

Concentration and distribution of heavy metals- The historical sediment data regarding the heavy metal input in one specific area are ensured by the heavy metal concentrations and distributions in surface sediments. The surface sediment samples are also used as environmental indicators to express the current quality status of marine systems for many pollutants [[10]].

The distribution of some trace metals (e.g., As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Rb, Sr, Zn, Zr and V) relating to the heavy metal pollution was investigated in both campaigns. The heavy metal concentrations were determined in grab/core sediment samples to evaluate their levels and spatial distribution in the port area. The trace element contents were investigated in the siltyclay fraction of the marine sediments. The average and fluctuations of the heavy metals content in all investigated sediment samples are listed in [9]. From the investigations performed in 2011 we noticed that the heavy metal contents are below the maximum allowable limits, and only incidentally, are found some relatively higher values, not involving, however, any environmental risk (see [8]-Line A and, respectively, [7]). For some elements the exchangeable concentrations in some sediment samples were found to be very close or above the allowable limits: Cr (mean values of 44.17±17.15 mg/kg, compared to 50 mg/kg), Ni (mean values of 28±7.54 mg/kg, versus 30 mg/kg), Pb (mean values of 22±19.68 mg/kg, opposed to 30 mg/kg) and As mean values of 13±9.84 mg/kg, contrasting to 12mg/kg). These relatively elevated values could be associated with the natural geological background (rock particles, minerals, soils) of these elements in the sediments, or most probably, as a result of the anthropogenic impact (the existence of some discharges containing high levels of Cr, Ni, Pb and As, or superadded quantities from artificial sources). Based on the areal distribution of the heavy metal contents within the surface sediments ([6]), generally, it was noticed that the lowest values are registered in the southeastern part of the Midia Port, at the mouth entrance from the sea. The tendencies for the minimum values are also observed in The Cargo Terminal Area, and in the central part of The Oil Terminal Enclosure Area(see [5], for the site location). Even if it was not exceeded the maximum content level, the highest values for the heavy metal contents were generally identified in the surface sediments sampled into the following zones: The Danube - Black Sea Canal Lock, The Ships Transit Area and Waste Oil Buffer Area(see [4], for these site locations). However, it has been observed that the trend of the heavy metals distribution that was investigated in the stations (e.g., MDA 11-11, e.g., MDA 11-12, e.g., MDA 11-14 and e.g., MDA 11-14) gathered from the Marine Area, namely, in the eastern and southern external part of the Midia Port, (see [3], for site locations) shows a much lower level compared to the sediment samples collected within the aquatory. The decreasing trend may be probably associated with the longitudinal marine coastal current, oriented from north to south, coming from the Danube Delta. So, the possible elevated concentrations of the heavy metals could be driven away further seaward through transport and could be diluted by the “uncontaminated” water flow. The waters coming from this area are much “cleaner” compared to the natural and anthropogenic background that characterizes the Midia Port area.

Table 3

Summary of the heavy metal indicators tested on the Midia Port sediment samples.

Line AHeavy metals content in surfcial sediment samples collected in 2011; (n=24)
ValuesCr (mg/kg)Cu (mg/kg)Fe (%)Mn (mg/kg)Ba (mg/kg)Ni (mg/kg)
Min21513072312
Max85145356524544
Mean44±17.1540±34.112±0.62434±7791±55.0928±7.54
ValuesZn (mg/kg)Pb (mg/kg)Cd (mg/kg)As (mg/kg)Hg (mg/kg)
Min212030.02
Max222922431.09
Mean87±46.4222±19.680±0.4913±9.840.21±0.26
Line BHeavy metals content in surficial sediment samples collected in 2012; (n=10)
ValuesCaCO3 ( %)Fe2O3 (%)TiO2 (%)Zr (mg/kg)Ba (mg/kg)Sr (mg/kg)Rb (mg/kg)Zn (mg/kg)
Min15.853.330.571681761977248.18
Max17.064.990.7723867623096155.99
Mean16.45±0.434.17±0.680.67±0.07205.90±23.92 335.10±153.40218.80±9.85 81.50±8.8688.68±37.61
ValuesNi (mg/kg)MnO (%)Cr (mg/kg)V (mg/kg)Co (mg/kg)Pb (mg/kg)Cu (mg/kg)
Min15.390.0532514.5819.714.54
Max32.020.0811312810.4573.99110.6
Mean24.11± 5.820.07± 0.0179.70± 21.4992.10± 22.347.33± 1.9737.91± 20.4243.52± 32.55
Line CHeavy metals content in core sediment samples collected in 2012; (n=5)
ValuesCaCO3 (%)Fe2O3 (%)TiO2 (%)Zr (mg/kg)Ba (mg/kg)Sr (mg/kg)Rb (mg/kg)Zn (mg/kg)
Min16.533.170.531701902416427.74
Max22.824.610.682543074159774.29
Mean19.28± 2.293.94± 0.510.61± 0.06200.60± 33.89246.20± 5193 316.60± 85.7678.40± 11.8454.05± 17.27
ValuesZn (mg/kg)Ni (mg/kg)MnO (%)Cr (mg/kg)V (mg/kg)Co (mg/kg)Pb (mg/kg)
Min27.7415.510.0740375.4819.3
Max74.2927.990.098210010.5336.53
Mean54.05± 17.2722.71± 5.000.08± 0.0159.20± 15.1675± 5.938.60± 2.0429.69± 6.72
Figure 4 Areal distribution of the heavy metal contents considered in the surface sediments, from the Midia Port area (Source image:On line at: http://www.google.com/earth/index/html., with addings). Note: the heavy metal contents are expressed in mg/kg; the colour scale ranges from blue (low values) to red (high values); even if, in the investigated perimeter the results agreed with the environmental standards, it is interesting to notice the spatial distribution pattern of the heavy metal concentrations in the Midia Port sediments.
Figure 4

Areal distribution of the heavy metal contents considered in the surface sediments, from the Midia Port area (Source image:[2], with addings). Note: the heavy metal contents are expressed in mg/kg; the colour scale ranges from blue (low values) to red (high values); even if, in the investigated perimeter the results agreed with the environmental standards, it is interesting to notice the spatial distribution pattern of the heavy metal concentrations in the Midia Port sediments.

Nevertheless, in the marine area, there are obvious differences between the investigated samples. The sources of these differences are mainly due to the continuous exchange of waters, between the port area and surroundings, and backwards, being also connected with the natural background and the industrial inputs. Thus, the surrounding sea water current circuit could bring and put into permanent motion the different inputs from the Danube-Black Sea canal and from the harbour mouth, as well as from the aquatory, towards the sea and backwards.

A series of other complementary heavy metal analyses were performed in 2012 to complete the investigated areas with new data, and also to figure the vertical distribution of the heavy metals in core sediments.

The results of the analyses have shown that the heavy metal contents in most samples are within the allowable limits concerning the environmental contamination evaluation24. The average and fluctuations of the heavy metals content in surface sediment samples are listed in Table 3-Line B. Only some sediment samples registered values that were found to be very close or above the natural background levels (e.g., Ba, Zn, Cr, Pb and Cu) compared to other investigated stations. These exchangeable levels could be linked probably to man-made sources. It is worth mentioning that these concentrations no pose any potential environmental hazards.

The concentrations of the heavy metals analyses performed on core samples are shown in Table 3-Line C. The informal interpretation related to the vertical profiles of the heavy metals in the sediment core (e.g., MDA 12-25) display a non-uniform pattern distribution. For instance, Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Zn and Zr, exhibit a series of fluctuations along the core, with content values that gradually increase in the median part. Along the core, the heavy metals content also changed perceptibly, with apparent variations. Starting with the median part of the core that is characterised by noticeable changes in the heavy metals content, it was figured a decrease upward.

Based on the mean concentration of the heavy metals in core sediment, the levels of most investigated sediments are slightly higher (very close or above the natural background levels), being concentrated in the median part of the core (e.g., between 30-79 cm), compared to the deeper layers (e.g., between 88-95 cm) and respectively, surface layers (e.g., between 1-8 cm). For all that, the heavy metal concentrations have not shown up values that could be considered threatening. Taking into consideration that the heavy metal investigations, both in the surface sediments and along the core, sampled in 2011 and 2012, were performed on samples gathered from an area quite strongly influenced by various port activities and port-related industrial activities it can be estimated that the Midia Port sediments are not severely polluted with heavy metals. These investigated sediment samples have been assessed as part of “moderate” quality status and, respectively “good” quality status.

Biological testing- The microbiological assays applied to sediment samples involved a series of tests with Fecal Enterococci, Escherichia coli, Sulphite-reducing clostridia, Salmonella spp., as well as Yeast and fungi. It is worth mentioning that from all of these, only Salmonella spp. indicates a negative feedback for some sediment samples. Other sediment samples were tested positive for Salmonella spp.(e.g., MDA 11-01, MDA 11-02, MDA 11-09 and MDA 11-18), implying the presence of a contamination level. A variety of sources could be responsible for these pathogens in the marine ecosystem, but more likely, in this case, the contamination could be linked to the inadequate water filtration and purification systems of vessels. An ecotoxicological assessment of marine sediments was performed using standardised laboratory bioassays with Vibrio fischeri, Brachionus plicatilis and Phaeodactillum tricornutum. Through the medium of the specific bio test with Vibrio fischeri, some of the sediment samples were classified as highly toxic (e.g., MDA 11-02, MDA 11-21) and toxic (e.g., MDA 11-18, MDA 11-24). The others are considered to belong to very low toxicity, slightly toxic, moderately toxic or nontoxic category.

In the issue, the results of the chemical analysis of some specific organic compounds and heavy metals carried on marine sediments allow their separation in three groups in consonance with the identified level of contamination and appropriately to environmental standards.

So, the following categories have been considered:

  1. “red” class - represented by highly contaminated sediments with organic compounds, that are assigned to “low” quality status. The increment of hydrocarbons (expressed as mineral oils) - C>12, PAH’s and PCB’s concentrations were noticed in most samples collected from the investigated perimeter (e.g., The Cargo Terminal Area, The Oil Terminal Enclosure Area The Ships Transit Area, The Waste Oil Buffer Area and the Marine Area).

  2. “yellow” class - represented by moderately contaminated sediments with organic compounds (e.g., hydrocarbons (expressed as mineral oils) - C>12, PAH’s and PCB’s), as well as heavy metals (e.g., Cr, Ni, Pb, As, Ba, Cu etc.), that are designated to “medium” quality status. To some extent, elevated values were found to be very close, relatively close or above to the stipulations. The content levels in question were encountered in sediment stations gathered from the all investigated zones, as The Cargo Terminal Area, The Oil Terminal Enclosure Area, The Ships Transit Area, The Waste Oil Buffer Area and the Marine Area.

  3. “green class” - represented by no contaminated sediments that are attributed to “good” quality status.

5 Conclusions

The emphasis of this study is on the potential impact of the Midia Port and its effects in and around the surrounding marine water and sediment environments. This is a very important issue due to the increased input of contaminants into the coastal environments in the recent past and current port-related industrial and commercial activities. The results of this study clearly indicate that the research goals have been achieved. More importantly, a general overview about the Midia Port environmental diagnosis has been appropriately asserted, taking into account the lack of relevant historical data for this area.

The analyses of water and sediment samples from the Midia Port area denoted generally, good environmental conditions related to the different physical-chemical and biological parameters even with the local expansion in terms of port-related activities.

The investigated parameters in measured water samples related slight fluctuations based on station locations. Some of the parameters show inconsistent values at some stations due to anthropogenic sources related to the particularities of the each investigated water sector. In this case, the water deterioration may be linked to a potential contamination from the diffuse sources of industrial origin, which impact the study area (port activities and port-related industrial activities). The results provided an overall viewpoint of the current situation of water quality status showing that the port waters have a lower level of contamination, as the water quality is slightly impaired. Based on visual field observations, it can be noticed that the port waters can sustain the aquatic life.

As regards the sediment, the analysis of the physical properties (compositional, textural and structural attributes) shows that these are consistent with the coastal geomorpholgical features of the marine investigated area. In particular, each of the delineated perimeters show particularities, different lithological contents and describes various particle size characteristics. The measured chemical parameters in sediment samples showed wide variations depending on site location. Some of the parameters can be considered critical, at some stations, probably as a result of different activities that impact the investigated sites. For the sediment quality, the investigated sediment samples were assessed as uncontaminated (“green” class), moderately contaminated (“yellow” class) and highly polluted (“red” class). Most of the surface sediment samples are highly polluted and contain significant enrichment of organic compounds as hydrocarbons (expressed as mineral oils)-C>12, PAH’s and PCB’s. The moderately polluted sediment samples displayed notable quantities of hydrocarbons (expressed as mineral oils)-C>12, PAH’s, PCB’s and exchangeable levels of heavy metals encountered to be very close or relatively close to the recommendations. The presence of higher levels of these organic compounds it was expected, taking into consideration the diversified industrial activities of the local area. The concentrations of the heavy metals in the sediment samples were quite variable and no patterns of distribution were established.

The results obtained from the analyses of water and sediments suggested that the enrichment levels of some chemical compounds from the investigated perimeter could generally reflect the past and current anthropogenic inputs as responsible for the environmental quality in the investigated area.

Finally, the results of this study provide a reference for the recent situation in the Midia Port area, as well as for future investigations related to the medium and long-term evolution of the environmental conditions.

Acknowledgements

The work of this paper was accomplished with the scientific and technical assistance provided by the National Institute for Research and Development - GeoEcoMar (Romania), during the SEDI.PORT.SIL.-Project, Life 09ENV/IT/000158. In this sense, we wish to express our appreciation to Italian team who contributed to the achievement of this study by conducting various analyses of water and sediment in their laboratories. Also, this work was partially supported by strategic grant POSDRU/89/1.5/S/58852; Project “Postdoctoral program for training scientific researchers” co-financed by the European Social Found within the Sectorial Operational Program Human Resources Development 2007-2013. The authors would like to thank the Managing Editor and anonymous reviewers, for their valuable comments and suggestions that help improve the quality of this paper notably.

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Received: 2013-8-7
Accepted: 2015-10-17
Published Online: 2016-3-22
Published in Print: 2016-3-1

© 2016 I. Catianis et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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