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Major oxides concentrations (%) detected in the investigated sediments of Port of Koper and their basic statistics.
Source publication
Heavy metal abundance and potential environmental risks are reported for surface sediments (n = 21) from the Port of Koper area, Republic of Slovenia. The enrichment factor (EF) indicates minor enrichment in arsenic (As), cadmium (Cd), copper (Cu), molybdenum (Mo), lead (Pb), antimony (Sb), and zinc (Zn), moderately to severely enriched with nickel...
Contexts in source publication
Context 1
... concentrations of SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, TiO2, P2O5, MnO, and Cr2O3, detected in the sediment samples, are summarised in Table 3. The abundance of the major oxides in the sediment samples is very similar, especially for Na2O, K2O, TiO2, P2O5, MnO, and Cr2O3. ...Context 2
... flysch basin is composed of carbonates and clastic rocks, especially siltstones and mudstones [24,48]. Additionally, the obtained results were compared to consensus-based sediment quality guidelines (SQGs), defined by [43] (Table 3). A comparison of sediment heavy metal concentrations with the consensus-based TEC and PEC values revealed that only mean concentrations of Ni are higher than both the TEC and PEC special values. ...Context 3
... plagioclase, chlorite, and muscovite/illite originated from flysch geological background. Fe, K, and Al were found in the silt fraction, which is prevailing in location 3. Additionally, the obtained results were compared to consensus-based sediment quality guidelines (SQGs), defined by [43] (Table 3). A comparison of sediment heavy metal concentrations with the consensus-based TEC and PEC values revealed that only mean concentrations of Ni are higher than both the TEC and PEC special values. ...Citations
... Less attention was paid to recent sediment near the spring, and also to the amount and composition of organic matter in the sediment, which was the goal of our study. In general, the sedimentological, mineralogical, and geochemical composition of sediment around sulfur springs is consistent with all previous studies (Ogorelec et al. 1981(Ogorelec et al. , 1987(Ogorelec et al. , 1997Covelli et al. 2006;Rogan Šmuc et al. 2018;Žvab Rožič et al. 2022) and reflects the geological characteristics of the wider Gulf of Trieste area. ...
... The sediment of the studied depressions where the sulfur spring occurs is granulometrically classified as silty sand and sandy silt, with the largest grains (sand, gravel) represented by shell fragments and particles of organic matter. Sediments from previous studies in Bay of Koper are somewhat finer and were classified in the silty clay textural group, rich in bioclastic fragments (foraminifera and bivalves) (Ogorelec et al. 1987Rogan Šmuc et al. 2018). The coarser sediment in the vicinity of sulfur springs can be explained as "washed" due to the outflow of spring water from the sediment. ...
... The only alluvial sediments were studied in this way in a borehole V3, located in the mouth of the Rižana River (Ogorelec et al. 1987), which has exclusively flysch hinterland and cannot be directly compared with our study area, which is more inside the bay. The M05 depression with the sulfur spring is shallower (24.6 m bsl) and was probably formed entirely from marine Holocene sediments, which is why the characteristics of the sediment are comparable to those of the surface sediments of the Bay of Koper (Ogorelec et al. 1981(Ogorelec et al. , 1987(Ogorelec et al. , 1997Rogan Šmuc et al. 2018;Žvab Rožič et al. 2022). ...
Purpose
This work highlights the sedimentary characteristics and the role of submarine sulfur-rich karstic springs in the distribution of benthic foraminifera in the northern part of the Adriatic Sea (Bay of Koper). Little is known about how local conditions such as temperature and sulfur bursts may influence sediment properties, benthic habitat variability, and composition of foraminiferal assemblages. Here we compare the distribution of total and living benthic assemblages in surface sediment samples collected from a funnel-shaped depression created by submarine sulfur springs.
Materials and methods
Sampling was performed at water depths between 24.6 and 32.2 m in fine-grained sandy silt to silty sand (partially washed). Sedimentological, mineralogical, and geochemical analyses of the sediment were carried out and the distribution of benthic foraminifera living around the springs was studied.
Results and discussion
In general, sediment characteristics (i.e., mineralogical, geochemical, and organic content) around the sulfur springs do not show prominent deviations from the marine surface sediment of the area; however, some differences exist among depressions of different depths. Deeper depressions in the lower parts probably extend to older continental sediments of Late Pleistocene age with alluvial features, while shallower depressions were formed entirely in Holocene marine sediments typical of a wider area. Only one of the five samples (M05) contained living foraminifera in sufficient abundance for biocenosis research. The benthic foraminiferal assemblages of moderate diversity are composed of opportunistic species. Elphidium translucens, Ammonia ex gr. tepida, Haynesina depressula, and Porosononion granosum dominate, while A. neobeccarii, Reussella spinulosa, and Textularia bocki are subordinate.
Conclusions
The distribution and diversity of foraminifera in the sediment near sulfur springs can be explained by several factors and their interactions. The intensity of the spring discharge affects the mixing/oxygenation of the sediment, the shape of spring depressions, and the granulometry of the coarser sediment around the springs. Sediment characteristics indicate different types of sediment origin. This is related to and can be explained by the depth of spring depressions.
... The complex biogeochemical processes that occur in coastal transitional environments are best understood in small and semi-enclosed systems. Accordingly, recent studies in the Adriatic coastal zone, based on a comprehensive investigation of sedimentological, mineralogical and geochemical properties of sediments, provided a better understanding of the various processes responsible for the distribution of metals in recent sediments (Apitz et al., 2009;Cukrov et al., 2011;Fiket et al., 2018;Ivanić et al., 2018;Jurina et al., 2015;Petranich et al., 2018;Pignotti et al., 2018;Rogan et al., 2018;Sondi et al., 2017;Surricchio et al., 2019;Zonta et al., 2020). ...
The history of metal pollution in the semi-enclosed and human-influenced marine system of the Boka Kotorska Bay (Southern Adriatic) was studied considering geological composition of the surrounding catchment, the sedimentation rate and the mineralogical and early diagenetic processes in the recent sediments. The determination of background concentrations of metals, undertaken for the first time in this environment, proved to be particularly important for Ni and Cr, which are naturally enriched in the sediments of the southern Adriatic. The results showed widespread moderate contamination with Pb and Sn since the 1970s, while the upper layers of sediments near shipyards, marinas and urban areas were more contaminated with Sn, Cu, Pb, Zn, Cd, As, Sb and Mo. The transport of material through the narrow straits separating different parts of Boka Kotorska Bay resulted in a different geochemical composition of the smaller bays and a limited distribution of contaminated sediments from local sources.
... Reducing conditions leads to the dissolution of Fe/Mn secondary oxide minerals and releases their sorbed metals into the water column Häusler et al., 2018), which are more easily bioavailable (Rogan Šmuc et al., 2018). Under anoxic conditions, sulfide minerals of many metals are formed, remaining stable (Łukawska-Matuszewska et al., 2019). ...
... The hypoxic and anoxic zones in the bottom water affect the fate of metals soluble in water or locked in secondary mineral phases (Myllykangas et al., 2017;Shahabi-Ghahfarokhi et al., 2021b). In the case of the shift from anoxic to oxic, solubilized metals are transported into its water column, which is readily bioavailable and thus can enter the food web and cause metal bioaccumulation in aquatic ecosystems (Filgueiras et al., 2003;Rao et al., 2008;Rogan Šmuc et al., 2018). The binding and chemical forms that influence metals' bioavailability could be studied with sequential chemical extraction (SCE) schemes (Rogan Šmuc et al., 2018). ...
... In the case of the shift from anoxic to oxic, solubilized metals are transported into its water column, which is readily bioavailable and thus can enter the food web and cause metal bioaccumulation in aquatic ecosystems (Filgueiras et al., 2003;Rao et al., 2008;Rogan Šmuc et al., 2018). The binding and chemical forms that influence metals' bioavailability could be studied with sequential chemical extraction (SCE) schemes (Rogan Šmuc et al., 2018). Water-soluble fraction compounds are mostly bioavailable and pose direct and high risks to the ecosystems (Filgueiras et al., 2003;Rao et al., 2008;Rogan Šmuc et al., 2018). ...
To bring life back to anoxic coastal and sea basins, reoxygenation of anoxic/hypoxic zones has been proposed. This research focuses on the metals released during the oxidization of sediments from two locations in the anoxic Eastern Gotland Basin under a laboratory-scale study. Triplicate experimental cores and reference cores were collected from the North and South Eastern Gotland Basins. The oxygenation of the water column took place over a 96-hour experiment in a dark and 5 °C environment. In 12 and 24 hour intervals, the surface waters were exchanged and, over time, analyzed for pH, electroconductivity (EC), total organic carbon (TOC), near-total metal concentrations, and the top samples (0–10 cm) were analyzed with 3-step (E1: water-soluble, E2: exchangeable, and E3: organic-bound) sequential chemical extraction (SCE). Results show stable pH and decreasing EC in the column waters. The EC indicates that metals are released in the initial phases (12 h) of reoxygenation for both sites. Arsenic, Ba, Co, Mn, Rb, U, K, Sr, and Mo are released into the water column during the 96 hour experiment, and based on the calculations for the entire East Gotland Basin, would mean 8, 50, 0.55, 734, 53, 27, 347,178, 3468, and 156 μg L⁻¹ are released, respectively. Elements Mn, Mo, U, and As are released in higher concentrations during the experiment than previously measured in the Eastern Gotland Basin, which provides vital information for future proposed remediation and natural geochemical processes with their known environmental impacts. The SCE results show that redox-sensitive metals (Mn, U, and Mo) are released in the highest concentrations into the solution. The relationship between the highest released metals (beside redox-sensitive) into solution over the oxygenation and their initial abundant phase is noticed, where the smallest released concentrations belong to K < Rb < Sr in E2, and As<Ba in E3, respectively.
... With its activities, the port represents a potential source of pollution for different environmental matrices: air, water, sediments, and soil. Therefore, several studies have been carried out on this issue (Žitnik et al., 2005;David et al., 2007;Cepak and Marzi, 2009;Zuin et al., 2009;Mladenović et al., 2013;Zupančič and Skobe, 2014;Rogan Šmuc et al., 2018). The results of above mentioned studies show that the ecological quality status of the seafloor sediments and water is better than in other ports of the Eastern Adriatic, that the accumulation of pollutants in the sediments is less significant due to the sedimentological characteristics (i.e., mineralogy, grain size) and the advective transport of particles. ...
... and Bulimina spp.) and increased concentrations of Ni, Zn, and As (Frontalini and Coccioni, 2008;Melis et al., 2019). Sediment from Bay of Koper were classified as silty clay, rich in foraminiferal and molluscan fragments (Ogorelec et al., 1987Rogan Šmuc et al., 2018). The grain-size of the sediment increases toward the central part of the bay (Ogorelec et al., 1987). ...
... The statistical grouping of the sites (Figure 5) can be explained by the geogenic origin, the different basic mineralogical characteristics of the sediment (carbonates at REF and siliciclastic at KPF1-KPF3) and the higher inflow of river water into the bay (between KPF3 and other sites). Although the minor positive signal of trace element concentrations might be recognized in the inner part of the port of Koper (KPF1 and KPF2), the values are generally within the background geological levels, which is in accordance with analyses previously published on the Bay of Koper (Ogorelec et al., 1987Rogan Šmuc et al., 2018). Contrary some trace elements (i.e., As, Cd, Cr, Cu, Ni, Zn) show higher concentrations compared to other locations in the Adriatic Sea (Adami et al., 1996;Aquavita et al., 2010). ...
The Bay of Koper is influenced by agricultural, urban, and port activities, therefore pollution from trace metals is a concern. A total of 20 sediment samples obtained from four 10-cm sediment cores were analyzed. Element concentration in the sediment of the bay was determined spatially and temporally from the recent surface to depth. The results were correlated with the composition and diversity of the benthic foraminiferal assemblages. Major element concentrations indicate natural lithogenic origin (which is also confirmed by mineralogical features). The benthic foraminiferal assemblages in sediment samples, although mainly composed of representatives of the Rotaliida, show moderate to high species diversity and are dominated by the pollution tolerant species Ammonia pakinsoniana, Haynesina sp., Valvulineria bradyana and the non-keel Elphidium sp. and subordinated by Ammonia tepida and Haynesina depressula. Canonical correspondence analysis (CCA) on foraminiferal species and trace element concentrations shows a possible control of some potential toxic elements (i.e., Cu, Ni, Pb, Zr, Cr, As) on the diversity and taxonomic composition of foraminiferal assemblages. Nevertheless, foraminiferal diversity and dominance in the bay are related to sediment characteristics such as sediment grain size, and the amount of terrigenous inflow rather than to the element concentrations of sediments. This study evaluated ecological conditions by using the Foram-AMBi and EcoQS indices. The values of the Foram-AMBI index reflect the good to moderate quality of ecological conditions, whereas high to poor ecological statuses were interpreted by calculating EcoQS.
... In this study, water and sediment quality were below the ranges found in other ports worldwide where much higher concentrations of nutrients, metals, and PAHs have been measured recently [61][62][63][64] while similar conditions have been observed in Australian ports [65] and in Port of Koper in the Northern Adriatic Sea [66]. It is worth noting that there are almost no recent scientific studies on the water and sediment conditions in terms of pollution in the ports of the North Sea. ...
The Port of Rotterdam is a heavily man-modified estuarine system, Europe's major seaport and home to a large number of chemical and petrochemical plants, many of which are supplied with distilled water from two demineralized water plants in Botlek and Maasvlakte. In this study, we assessed the ecological conditions near the brine outfalls and at a reference site unimpacted by brine focusing on the benthic macrofaunal composition. Overall, the analysis of the communities and species revealed a similar macrobenthic composition, although with lower abundance and diversity compared to the nearby North Sea environment. The outfall area of the Botlek demineralized water plant, which is a dead-end entirely marine waterway with no to little currents in contrast to the well flushed brackish environment of the outfall of the Maasvlakte demineralized water plant, was characterized by the lowest abundance of benthic macroinvertebrates, species richness and Shannon diversity index. Higher biodiversity values at the Maasvlakte demineralized water plant compared to the reference site were also associated with the presence of a large biogenic reef of the Pacific oyster Crassostrea gigas with specimens of over 8 years estimated age being observed, however with many dead individuals recorded at the time of surveys. The outfall area of the Botlek demineralized water plant also had the highest disturbance levels according to the results of AZTI's Marine Biotic Index (AMBI)in conjunction with Benthos Ecosystem Quality Index (BEQI). Its community was dominated by the opportunistic native species Capitella capitata and Varicorbula gibba, and species typical for organic matter enrichment such as Alitta succinea (native), Streblospio cf shrubsolii (native) and Theora lubrica (invasive), which correlates well with higher levels of anthropogenic pollution in this area. Generalized linear model (GLM) and distance-based multivariate linear model (DistLM) showed that the distance from the outfalls was an important factor in terms of brine impacts however explaining a small part of the variation observed. Similarity percentage analysis (SIMPER), multivariate analysis and permutational multivariate analysis (PERMANOVA) showed low similarity between and within study sites, confirming that high levels of heterogeneity exist within the estuarine system in terms of natural conditions and anthropogenic stress.
... In particular, heavy metal pollution in ADRION Region originates from sources such as land mining activities, like mercury mine of Idrija, Slovenia (Horvat et al., 2014;Gallmetzer et al., 2017), metallurgic industries, like Taranto industrial plants (Di Leo et al., 2013), oil refinery plants (Cukrov et al., 2011;Traven et al., 2015), old-type chlor-alkali plants (Mikac et al., 2006;Kljaković-Gašpić et al., 2006;Acquavita et al., 2012), municipal-sewage outflows (Cozzi et al., 2008;Cukrov et al., 2011;Joksimovic et al., 2020), harbors (container terminals, Cukrov et al., 2011), cruise tourism (Carić and Mackelworth, 2014;Joksimovic et al., 2019), by means of produced water discharge in offshore oil and gas extraction plants (Igwe et al., 2013). The presence of metals in the coastal environment of the Adriatic-Ionian basin is also due to natural, geogenic sources: the metals contained in the eroded rocky material are transported through rivers, as observed, for example, in the case of nickel in Koper Bay, Slovenia (Rogan Šmuc et al., 2018), or in the case of chromium and nickel in the lagoon area of Amvrakikos Gulf, Greece (Vasileiadou et al., 2016). ...
... The abundance of minerals, major oxides, and trace elements in the sediments of aquatic ecosystems (like lakes, rivers, and drains) is generally dependent upon a number of interior and exterior environmental factors. Most often the interior factors include a series of in-situ chemical, physical and biological processes such as sorption, bioturbation, waves, and currents as well as dredging, and shipping actions (Chiou and Kile, 2000;Point et al., 2007;Š muc et al., 2018). The exterior factors usually include the discharge of various anthropogenic contaminants (agricultural, industrial, mine, and municipal wastewater effluents) into the lakes (Szefer et al., 1996;Bessa et al., 2018;Shalby et al., 2020). ...
Qaroun Lake (El-Fayoum, Egypt) is a saline endorheic basin within the northern arid zone of El-Fayoum, Egypt. Mineralogical and geochemical investigations were conducted on 32 samples from the Holocene sediments of the lake and relevant drains to get information on the sediment type and maturity, source rocks, weathering, environments of deposition, and tectonic settings. The lithology of sediment samples consists of pelites and sandstones with low compositional maturity degree characterizing first cycle deposits. The sediments are mainly composed of quartz and calcite, with minor phases including feldspar, dolomite, saponite, kaolinite, hematite, goethite, gypsum, and halite minerals. The lake's sediments are enriched in Cr, Mo, Hf, Pr, and Nd and depleted in Ni, Zn, As, Rb, Y, Sn, Sb, Ba, and La, while the drain's ones are enriched in V, Sr, Zr, Cr, Mo, Hf, Pr and Nd and depleted in Co, Zn, As, Rb, Y, Sn, Sb, Ba, Pb, and La, compared to the earth's crust shale. These sediments are mainly sourced from intermediate and felsic igneous rocks, as well as, calcareous and sandstone materials incorporated in the nearby geologic formations and soils. The high SiO2 and the low Fe2O3 and MgO concentrations reflects the acidic nature of rocks in the source area. The SiO2 and (Al2O3+K2O+Na2O) binary plot indicates the prevailing semiarid to arid climatic conditions during the sedimentation. High values of CIA and PIA and low values of ICV as well as the relationship between K2O/Na2O and K2O+Na2O contents reveal relatively moderate to a high degree of chemical weathering in the source area. The elemental ratios and geochemical discrimination diagrams show that the sedimentary environments are fluviatile-deltaic environments that experienced oxic to dysoxic conditions. The geochemical characteristics of the lake sediment samples point to a transitional tectonic setting from oceanic island arc to active continental and passive continental margins, while those of the drains samples indicate an active continental tectonic setting. The obtained data can be meaningful for the development of Qaroun lake environment.
... Sediment quality assessment guidelines (SQGs) represent a common approach and the first step for assessing the quality of sediments, i.e. heavy metal contamination in sediment (MacDonald et al. 2000;Violintzis et al. 2009). The SQGs are useful for sediment quality control to identify which chemicals can contribute most to toxicity and for assessing the degree to which the chemical composition of sediment could adversely affect aquatic organisms (Pejman et al. 2015;Šmuc et al. 2018). Two data sets of SQG for marine sediments were applied in this study (Table 2): effects range lows (ERLs)/effects range medians (ERMs) (Long et al. 1995) and threshold effect levels (TELs)/probable effect levels (PELs) . ...
Concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn, and Fe measured at forty locations in the Boka Kotorska Bay were used to monitor the spatial and temporal quality of sediment and to assess surface sediment contamination over the last 15 years. This ecological geochemistry assessment was made using two classes of pollution indices: single indices concerning the investigated elements (contamination factor (Cf)) and integrated indices concerning the locations (pollution load index (PLI), potential ecological risk index (RI), mean effects range median quotient (MERMQ), toxic risk index (TRI), contamination severity index (CSI)). The distribution of all indices was geostatistically mapped and several hotspots were identified. Based on the indices applied in the risk assessment, the mean contribution of individual metal species to the total risk was determined and presented in the following order: Cd > Hg > As > Pb > Ni > Cu > Cr > Zn. This study revealed that Cd and Hg were at the top of the risk list among the examined elements. The temporal distribution of Hg has shown a decreasing trend during the period 2005–2019, while the presence of Cd in the Bay environment is of major concern. The results revealed that the most polluted part of the investigated area was Tivat bay within the Boka Kotorska Bay. Multivariate statistical analysis of pollution indices resulted in multicollinearity, which enabled the use of a reduced number of indices with an acceptable risk estimation.
... Extreme concentrations of certain elements occasionally occur at some locations, so this is one of the reasons for the increased values compared to the average concentrations of surface sediment in the South Adriatic. Compared to the results from other parts of the Adriatic Sea, our results were in the same range as the results obtained for the different parts of the Adriatic [11,13,[47][48][49][50][51][52][53][54][55][56][57][58]. The Montenegrin coastal waters are still under the influence of anthropogenic eutrophication (sewage, domestic, and agricultural wastes, effluents from industry, ports and shipping area, nautical tourism) and the repercussions of industrial pollution, which are still visible [13,59,60]. ...
This study presents a review of available data on heavy metal contents in sediments collected along the Montenegrin coast, starting from 2005 to recent years. The aim was to evaluate the pollution level of Montenegrin coastal sediments by determining the concentrations of heavy metals (Fe, Mn, Zn, Cu, Ni, Pb, Cr, Cd, As, and Hg). The pollution status was evaluated using the contamination factor, pollution load index, and geo-accumulation index, as well as the statistical methods, such as cluster analysis (CA). This study showed that concentrations of individual metals at some locations were extremely high. Mean metal concentrations (mg/kg) in sediment samples during whole investigated period were in the following order: Fe > Mn > Zn > Cr > Ni > Pb > Cu > As > Hg > Cd. The calculated contamination factor and pollution load index values indicated enrichment by either natural processes or anthropogenic influences. According to contamination factor (CF), the contents of Zn, Pb, Ni, Cr, and Hg are responsible for very high contamination. Extreme Igeo values were found for Zn, Cu, Pb, and Cd (strongly or strongly to extremely polluted) for the sediment samples from the location Port of Bar in 2011. Also, the location Ada Bojana was characterized as strongly to extremely polluted with Ni in 2019, and Porto Montenegro was extremely polluted with Hg during 2016 and 2019 with the Igeo values of 6.18 and 6.28, respectively. Locations with the highest PLI values in surface sediments were Porto Montenegro (2018–2019) and Port of Bar (2011, 2014). Cluster analysis grouped the examined metals into two main clusters, indicating possible similar origins of the elements within the same cluster.
... Anoxic conditions release adsorbed metals from the surface of iron (Fe)/manganese (Mn) hydroxides, and they instead form metal sulfides (Neff 2002c;Beldowski et al. 2010). However, contrary to the assumptions of Borg andJonsson (1996) andRogan Šmuc et al. (2018) report higher concentrations of Pb from reduced (anoxic) sediments related to the formation of stable Fe and Mn complexes. Cadmium and Zn are also under the influence of oxic/anoxic conditions (Pohl and Hennings 1999;Neff 2002a;b). ...
... Cadmium and Zn are also under the influence of oxic/anoxic conditions (Pohl and Hennings 1999;Neff 2002a;b). Under oxic conditions, Cd is released when organic matter (OM) is mineralized (Neff 2002a;Rogan Šmuc et al. 2018), while Zn is adsorbed to Fe/Mn oxides and OM (Neff 2002b). Overall, Cd, Zn, and Pb are reported to be more abundant in oxic than anoxic waters (Öztürk 1995;Pohl and Hennings 1999); additionally, the foremost soluble Cd, Zn, and Pb species in anoxic waters originate from the bisulfide complexes of these metals (Öztürk 1995;Neff 2002c). ...
... Image is developed in Affinity Designer Software version 1.7.3.481. References (Öztürk 1995;Borg and Jonsson 1996;Pohl and Hennings 1999;Neff 2002a;b;Ingri et al. 2014;Rogan Šmuc et al. 2018;Beldowski et al. 2010). ...
The unsustainable settlement and high industrialization around the catchment of the Baltic Sea has left records of anthropogenic heavy metal contamination in Baltic Sea sediments. Here, we show that sediments record post-industrial and anthropogenic loads of Cd, Zn, and Pb over a large spatial scale in the Baltic Sea. We also demonstrate that there is a control on the accumulation of these metals in relation to oxic/anoxic conditions of bottom waters. The total concentrations of Cd, Zn, and Pb were obtained with the near-total digestion method in thirteen cores collected from the Bothnian Bay, the Bothnian Sea, and the west and central Baltic Proper. The lowest average concentrations of Cd, Zn, and Pb were observed in Bothnian Bay (0.4, 125, 40.2 mg kg⁻¹ DW, respectively). In contrast, the highest concentrations were observed in the west Baltic Proper (5.5, 435, and 56.6 mg kg⁻¹ DW, respectively). The results indicate an increasing trend for Cd, Zn, and Pb from the early nineteenth century until the 1970s, followed by a decrease until 2000–2008. However, surface sediments still have concentrations above the pre-industrial values suggested by the Swedish EPA (Cd is 0.2, Zn is 85, and Pb is 31 mg kg⁻¹ DW). The results also show that the pre-industrial Cd, Zn, and Pb concentrations obtained from 3 cores with ages < 1500 B.C. were 1.8, 1.7, and 1.2 times higher, respectively, than the pre-industrial values suggested by the Swedish EPA. To conclude, accumulations of metals in the Baltic Sea are governed by anthropogenic load and the redox conditions of the environment. The significance of correct environmental governance (measures) can be illustrated with the reduction in the pollution of Pb, Zn, and Cd within the Baltic Sea since the 1980s.
