Microbenthic community structure and trophic status of sediments in the Mar Piccolo of Taranto (Mediterranean,Ionian Sea)

This study aimed to assess the benthic ecosystem trophic status in a heavily polluted marine area and the response of the microbenthic community to multiple and diffuse anthropogenic impacts, integrating information coming from the active and resting (plankton’s cysts) components of microbenthos. Two sampling campaigns were carried out in the period 2013–2014 and four sampling sites at different levels of industrial contamination were chosen within the first and second inlet of the Mar Piccolo of Taranto. The chemical contamination affected to a higher extent the active microbenthos than the resting one. In the central part of the first inlet, characterised by more marine features, thrives a very rich and biodiverse microbenthic community. In contrast, at the polluted site near the military navy arsenal, extremely low densities (9576?±?1732 cells cm^?3) were observed for active microbenthos, but not for the resting community. Here, the high level of contamination selected for tychopelagic diatom species, i.e., thriving just above the surface sediments, while the other life forms died or moved away. Following the adoption of a 10 μm mesh, for the first time, resting spores produced by small diatoms of the genus Chaetoceros were found. Our results further indicate that although the Mar Piccolo is very shallow, the benthic system is scarcely productive, likely as a consequence of the accumulated contaminants in the surface sediments that probably interfere with the proper functioning of the benthic ecosystem.     

Sediment pollution and dynamic in the Mar Piccolo of Taranto (southern Italy): insights from bottom sediment traps and surficial sediments

Major and trace element, PAH, and PCB concentrations were measured in surface sediments and particles from sediment traps collected in the First and Second Basin of the Mar Piccolo (Gulf of Taranto) in two periods (June–July and August–September, 2013). The aim of the study was to evaluate pollution degree, sediment transport and particle redistribution dynamic within the area. Results confirm the higher contamination of sediments from the First Basin observed by previous researches, particularly for Cu, Hg, Pb, total PAHs, and total PCBs. Advective transport from the First to the Second Basin appears to be the leading transfer mechanism of particles and adsorbed contaminants, as evidenced by measured fluxes and statistical analyses of contaminant concentrations in surficial sediments and particles from sediment traps. Long-range selective transports of PAHs and microbial anaerobic degradation processes for PCBs have been also observed. These results are limited to a restricted time window but are consistent with the presence of transport fluxes at the bottom of the water column. This mechanism deserves further investigation and monitoring activities, potentially being the main responsible of pollutant delivering to the less contaminated sectors of the Mar Piccolo.     

‘End to end’ planktonic trophic web and its implications for the mussel farms in the Mar Piccolo of Taranto (Ionian Sea,Italy)

The Mar Piccolo is a semi-enclosed basin subject to different natural and anthropogenic stressors. In order to better understand plankton dynamics and preferential carbon pathways within the planktonic trophic web, an integrated approach was adopted for the first time by examining all trophic levels (virioplankton, the heterotrophic and phototrophic fractions of pico-, nano- and microplankton, as well as mesozooplankton). Plankton abundance and biomass were investigated during four surveys in the period 2013–2014. Beside unveiling the dynamics of different plankton groups in the Mar Piccolo, the study revealed that high portion of the plankton carbon (C) pool was constituted by small-sized (<2 μm) planktonic fractions. The prevalence of small-sized species within micro- and mesozooplankton communities was observed as well. The succession of planktonic communities was clearly driven by the seasonality, i.e. by the nutrient availability and physical features of the water column. Our hypothesis is that beside the ‘bottom-up’ control and the grazing pressure, inferred from the C pools of different plankton groups, the presence of mussel farms in the Mar Piccolo exerts a profound impact on plankton communities, not only due to the important sequestration of the plankton biomass but also by strongly influencing its structure.     

The Mar Piccolo of Taranto: an interesting marine ecosystem for the environmental problems studies

The National Project RITMARE (la Ricerca ITaliana per il MARE—Italian Research for the sea) started from 1 January 2012. It is one of the national research programs funded by the Italian Ministry of University and Research. RITMARE is coordinated by the National Research Council (CNR) and involves an integrated effort of most of the scientific community working on marine and maritime issues. Within the project, different marine study areas of strategic importance for the Mediterranean have been identified: Among these, the coastal area of Taranto (Ionian Sea, Southern Italy) was chosen for its different industry settlements and the relative impact on the marine environment. In particular, the research has been concentrated on the Mar Piccolo of Taranto, a complex marine ecosystem model important in terms of ecological, social, and economic activities for the presence also of extensive mussel farms. The site has been selected also because the Mar Piccolo area is a characteristic “on field” laboratory suitable to investigate release and diffusion mechanisms of contaminants, evaluate chemical–ecological risks towards the marine ecosystem and human health, and suggest and test potential remediation strategies for contaminated sediments. In this context, within the project RITMARE, a task force of researchers has contributed to elaboration a functioning conceptual model with a multidisciplinary approach useful to identify anthropogenic forcings, its impacts, and solutions of environmental remediation. This paper describes in brief some of the environmental issues related to the Mar Piccolo basin.     

Recent evolution of the physical–chemical characteristics of a Site of National Interest—the Mar Piccolo of Taranto (Ionian Sea)—and changes over the last 20 years

The Mar Piccolo of Taranto, classified as a ‘Site of National Interest’ (SIN), is a semi-enclosed basin divided into two inlets with lagoon features and sea influences, seriously affected by anthropic activities. In the framework of the RITMARE project, a study has been carried out to evaluate the functionality of this ecosystem. As part of this work, measurements of the water abiotic parameters were performed in order to assess the physical–chemical features of this area after the activation, in the last decade, of treatment plants for various urban and industrial dumping. Seawater intrusions and continental inputs, as well as several submarine freshwater springs, clearly affect physical–chemical characteristics of the water column in the two inlets. This finding suggests that small-scale patterns in water circulation have the potential to influence the chemical properties of the seawater. The comparison with a 20-year dataset reveals a drastic decrease in nutrient concentrations after the year 2000, validating the functionality of the treatment plants. The reduction of nutrient inputs into the basin (up to ?90 % in the first inlet characterized by lower hydraulic residence time) has changed the biogeochemical characteristics of the Mar Piccolo from being relatively eutrophic to moderately oligotrophic.     

Mar Piccolo of Taranto: Vibrio biodiversity in ecotoxicology approach

Microorganisms play an indispensable role in the ecological functioning of marine environment. Some species are sensitive while others are insensitive for a specific pollutant. The aim of this work is a preliminary study of the quantitative and qualitative distribution of cultivable vibrios in sediments and water samples characterized by different toxicity levels. For 1 year, in three suitably selected sampling stations of Mar Piccolo in Taranto (Ionian Sea, Italy), we have evaluated the toxicity level by Microtox® system, vibrios, total, and fecal coliform densities. The results of the Microtox® tests showed sediments characterized by an elevated level of toxicity, while the interstitial water of the same sites always showed biostimulatory phenomenon. The quantitative results show that vibrios and coliforms are more abundant in water than in sediment samples. The most often isolated strains were: Vibrio alginolyticus, Vibrio mediterranei, Vibrio metschinkovii, and Vibrio splendidus II. This work is the first example of study on the distribution of Vibrio species related to toxicity evaluation conducted by the Microtox® bioassay. The results show the different distribution of Vibrionaceae in two environmental matrices analyzed and characterized by different levels of toxicity.     

On the geotechnical characterisation of the polluted submarine sediments from Taranto

This paper reports the results of the first geomechanical laboratory experiments carried out on the polluted submarine clayey sediments of the Mar Piccolo in Taranto (South of Italy). The study had to face with extreme difficulties for the very soft consistency of the sediments and the contaminants. The mineralogy, composition and physical properties of the sediments were analysed, along with their compression and shearing behaviour. The investigation involved sediments up to about 20 m below the seafloor, along three vertical profiles in the most polluted area of the Mar Piccolo, facing the Italian Navy Arsenal. The experimental results were used to derive a preliminary geotechnical model of the site, necessary for the selection and design of the most sustainable in situ mitigation solutions. Moreover, the experimental data reveal that the clayey sediments of the most polluted top layer do not follow the classical geotechnical correlations for normally consolidated deposits. This seems to open interesting perspectives about the effects of pollutants on the geotechnical behaviour of the investigated sediments.     

Phytoplankton dynamics with a special emphasis on harmful algal blooms in the Mar Piccolo of Taranto (Ionian Sea,Italy)

The response of phytoplankton assemblages to the closure of urban sewage outfalls (USOs) was examined for the Mar Piccolo of Taranto (Mediterranean Sea), a productive semi-enclosed coastal marine ecosystem devoted to shellfish farming. Phytoplankton dynamics were investigated in relation to environmental variables, with a particular emphasis on harmful algal blooms (HABs). Recent analyses evidenced a general reduction of the inorganic nutrient loads, except for nitrates and silicates. Also phytoplankton biomass (chlorophyll a) and abundances were characterized by a decrease of the values, except for the inner area of the basin (second inlet). The phytoplankton composition changed, with nano-sized species, indicators of oligotrophic conditions, becoming dominant over micro-sized species. If the closure of the USOs affected phytoplankton dynamics, however, it did not preserve the Mar Piccolo from HABs and anoxia crises. About 25 harmful species have been detected throughout the years, such as the potentially domoic acid producers Pseudo-nitzschia cf. galaxiae and P seudo-nitzschia cf. multistriata, identified for the first time in these waters. The presence of HABs represents a threat for human health and aquaculture. Urgent initiatives are needed to improve the communication with authorities responsible for environmental protection, economic development, and public health for a sustainable mussel culture in the Mar Piccolo.     

Benthic ecosystem functioning in the severely contaminated Mar Piccolo of Taranto (Ionian Sea,Italy): focus on heterotrophic pathways

The benthic ecosystem functioning is a rarely applied holistic approach that integrates the main chemical and biological features of the benthic domain with the key processes responsible for the flux of energy and C through the system. For the first time, such conceptual model, with an emphasis on the heterotrophic pathways, has been applied to the sediments at four stations within one of the most polluted coastal areas in Italy: the Mar Piccolo of Taranto. The functioning of the benthic ecosystem was different according to the investigated site. Nearby the military arsenal, i.e., the main source of organic contaminants and heavy metals, the system seemed inhibited at all the investigated structural and functional levels. Slow microbial processes of C reworking together with very limited densities of benthic fauna suggested a modest transfer of C both into a solid microbial loop and to the higher trophic levels. On the other hand, the ingression of marine water through the “Navigabile” channel seemed to stimulate the organic matter degradation and, consequently, the proliferation of meiofauna and macrofauna. In the innermost part of the basin, the system functioning, to some extent, is less impacted by contaminants and more influenced by mussel farms. The organic matter produced by these bivalves fueled faster C reworking by benthic prokaryotes and enhanced the proliferation of filter feeders.     

Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto’s Mar Piccolo (Ionian Sea,Southern Italy)

In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment–water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m^?2 day^?1) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area.     

Oxygen,carbon, and nutrient exchanges at the sediment–water interface in the Mar Piccolo of Taranto (Ionian Sea,southern Italy)

In the shallow environment, the nutrient and carbon exchanges at the sediment–water interface contribute significantly to determine the trophic status of the whole water column. The intensity of the allochthonous input in a coastal environment subjected to strong anthropogenic pressures determines an increase in the benthic oxygen demand leading to depressed oxygen levels in the bottom waters. Anoxic conditions resulting from organic enrichment can enhance the exchange of nutrients between sediments and the overlying water. In the present study, carbon and nutrient fluxes at the sediment–water interface were measured at two experimental sites, one highly and one moderately contaminated, as reference point. In situ benthic flux measurements of dissolved species (O₂, DIC, DOC, N-NO₃ ^?, N-NO₂ ^?, N-NH₄ ⁺, P-PO₄ ^3?, Si-Si(OH)₄, H₂S) were conducted using benthic chambers. Furthermore, undisturbed sediment cores were collected for analyses of total and organic C, total N, and biopolymeric carbon (carbohydrates, proteins, and lipids) as well as of dissolved species in porewaters and supernatant in order to calculate the diffusive fluxes. The sediments were characterized by suboxic to anoxic conditions with redox values more negative in the highly contaminated site, which was also characterized by higher biopolymeric carbon content (most of all lipids), lower C/N ratios and generally higher diffusive fluxes, which could result in a higher release of contaminants. A great difference was observed between diffusive and in situ benthic fluxes suggesting the enhancing of fluxes by bioturbation and the occurrence of biogeochemically important processes at the sediment–water interface. The multi-contamination of both inorganic and organic pollutants, in the sediments of the Mar Piccolo of Taranto (declared SIN in 1998), potentially transferable to the water column and to the aquatic trophic chain, is of serious concern for its ecological relevance, also considering the widespread fishing and mussel farming activities in the area.     

Influence of trophic status on PCB distribution in lake sediments and biota

We investigated the relationship between trophic status and polychlorinated biphenyl (PCB) distribution in 19 Swedish lakes. We analyzed PCB in water, phytoplankton, zooplankton, fish and sediment during two sampling periods, in spring and summer. The mass of sigma PCB in the lake sediments was positively related to lake trophy, i.e. more PCBs were accumulated and buried in the sediment of eutrophic lakes than in oligotrophic lakes. In the oligotrophic lakes a greater fraction of the total PCB load was dissolved in water. We conclude that this is a result of higher sedimentation rates in eutrophic lakes and relatively lower turnover of organic carbon in the water column of the shallow, eutrophic lakes. In the stratified lakes, the amount of PCB per cubic meter in the epilimnion decreased from spring to summer. We suggest that sedimentation of plankton beneath the thermocline during stratification act as a sink process of PCBs from the epilimnion.     

Ecotoxicological effects of sediments from Mar Piccolo,South Italy: toxicity testing with organisms from different trophic levels

The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.     

Batch and column studies of the stabilization of toxic heavy metals in dredged marine sediments by hematite after bioremediation

The management of dredged sediments is an important issue in coastal regions where the marine sediments are highly polluted by metals and organic pollutants. In this paper, mineral-based amendments (hematite, zero-valent iron and zeolite) were used to stabilize metallic pollutants (As, Cd, Cu, Mo, Ni, Pb, and Zn) in a contaminated marine sediment sample. Mineral-based amendments were tested at three application rates (5 %, 10 %, and 15 %) in batch experiments in order to select the best amendment to perform column experiments. Batch tests have shown that hematite was the most efficient amendment to stabilize inorganic pollutants (As, Cd, Cu, Mo, Ni, Pb, and Zn) in the studied sediment. Based on batch tests, hematite was used at one application rate equal to 5 % to conduct column experiments. Column tests confirmed that hematite was able to decrease metal concentrations in leachates from stabilized sediment. The stabilization rates were particularly high for Cd (67 %), Mo (80 %), and Pb (90 %). The Microtox solid phase test showed that hematite could decrease significantly the toxicity of stabilized sediment. Based on batch and column experiments, it emerged that hematite could be a suitable adsorbent to stabilize metals in dredged marine sediment.     

Study of spatial and temporal distribution of antimicrobial in water and sediments from caging fish farms by on-line SPE-LC-MS/MS

An on-line solid phase extraction liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method for the determination of 12 antimicrobials in sediment and surface water was developed and validated. Furthermore, the spatial and temporal antimicrobials distributions in the sediment and in the water of four fish farms located in the hydroelectric dam of Ilha Solteira Reservoir in Brazil were investigated over four seasons in three sampling sites: at the fish cages, 100 and 1,000 m downstream far from the cages. The method was performed using an Agilent Zorbax 80 SB-C8 column (9.4 × 15 mm, 5 µm) as the loading column, and the Agilent Zorbax Eclipse Plus C18 column (3.0 × 100 mm, 3.5 µm) as a separation column within a run time of 13 min. The limits of quantification were less than 9 ng·L^?1 for the antibiotics in water and 16 µg·kg^?1 in sediment; the recovery ranged from 80 to 119%, with a variation coefficient less than 11%, and the repeatability was lower than 15%. Oxytetracycline was found in the water in all sample seasons. However, florfenicol was identified in April and October 2013 and January 2014, and tetracycline was present in July 2013. Regarding the sediment, oxytetracycline and tetracycline were found in all sampling periods, but chlortetracycline was only identified in January 2014. The spatial distribution of antimicrobials showed that the main pollution source came from the fish farms. This study demonstrated that the proposed method is reliable for the monitoring of antimicrobials in water and sediments and it showed contamination in both matrices from Ilha Solteira Reservoir.     

Coastal hydrogeological system of Mar Piccolo (Taranto,Italy)

The Mar Piccolo basin is an internal sea basin located along the Ionian coast (Southern Italy), and it is surrounded primarily by fractured carbonate karstic environment. Because of the karstic features, the main continental water inflow is from groundwater discharge. The Mar Piccolo basin represents a peculiar and sensitive environment and a social emergency because of sea water and sediment pollution. This pollution appears to be caused by the overlapping effects of dangerous anthropogenic activities, including heavy industries and commercial and navy dockyards. The paper aims to define the contribution of subaerial and submarine coastal springs to the hydrological dynamic equilibrium of this internal sea basin. A general approach was defined, including a hydrogeological basin border assessment to detect inflowing springs, detailed geological and hydrogeological conceptualisation, in situ submarine and subaerial spring measurements, and flow numerical modelling. Multiple sources of data were obtained to define a relevant geodatabase, and it contained information on approximately 2000 wells, located in the study area (1600 km²). The conceptualisation of the hydrogeological basin, which is 978 km² wide, was supported by a 3D geological model that interpolated 716 stratigraphic logs. The variability in hydraulic conductivity was determined using hundreds of pumping tests. Five surveys were performed to acquire hydro-geochemical data and spring flow-yield measurements; the isotope groundwater age was assessed and used for model validation. The mean annual volume exchanged by the hydrogeological basin was assessed equal to 106.93 10⁶ m³. The numerical modelling permitted an assessment of the mean monthly yield of each spring outflow (surveyed or not), travel time, and main path flow.     

Investigations into the differential reactivity of endogenous and exogenous mercury species in coastal sediments

Stable isotopic tracer methodologies now allow the evaluation of the reactivity of the endogenous (ambient) and exogenous (added) Hg to further predict the potential effect of Hg inputs in ecosystems. The differential reactivity of endogenous and exogenous Hg was compared in superficial sediments collected in a coastal lagoon (Arcachon Bay) and in an estuary (Adour River) from the Bay of Biscay (SW France). All Hg species (gaseous, aqueous, and solid fraction) and ancillary data were measured during time course slurry experiments under variable redox conditions. The average endogenous methylation yield was higher in the estuarine (1.2 %) than in the lagoonal sediment (0.5 %), although both methylation and demethylation rates were higher in the lagoonal sediment in relation with a higher sulfate-reducing activity. Demethylation was overall more consistent than methylation in both sediments. The endogenous and exogenous Hg behaviors were always correlated but the exogenous inorganic Hg (IHg) partitioning into water was 2.0–4.3 times higher than the endogenous one. Its methylation was just slightly higher (1.4) in the estuarine sediment while the difference in the lagoonal sediment was much larger (3.6). The relative endogenous and exogenous methylation yields were not correlated to IHg partitioning, demonstrating that the bioavailable species distributions were different for the two IHg pools. In both sediments, the exogenous IHg partitioning equaled the endogenous one within a week, while its higher methylation lasted for months. Such results provide an original assessment approach to compare coastal sediment response to Hg inputs.     

Volatilization of contaminants from suspended sediment in a water column during dredging

Remedial dredging of contaminated bed sediments in rivers and lakes results in the suspension of sediment solids in the water column, which can potentially be a source for evaporation of hydrophobic organic compounds (HOCs) associated with the sediment solids. Laboratory experiments were conducted in an oscillating grid chamber to simulate the suspension of contaminated sediments and flux to air from the surface of the water column. A contaminated field sediment from Indiana Harbor Canal (IHC) and a laboratory-inoculated University Lake (UL) sediment, Baton Rouge, LA, were used in the experiments, where water and solids concentration and particle size distribution were measured in addition to contaminant fluxes to air. A transient model that takes into account contaminant desorption from sediment to water and evaporation from the water column was used to simulate water and sediment concentrations and air fluxes from the solids suspension. In experiments with both sediments, the total suspended solids (TSS) concentration and the average particle diameter of the suspended solids decreased with time. As expected, the evaporative losses were higher for compounds with higher vapor pressure and lower hydrophobicity. For the laboratory-inoculated sediment (UL), the water concentrations and air fluxes were high initially and decreased steadily implying that contaminant release to the water column from the suspended solids was rapid, followed by evaporative decay. For the field sediments (IHC), the fluxes and water concentrations increased initially and subsequently decreased steadily. This implied that the initial desorption to water was slow and that perhaps the presence of oil and grease and aging influenced the contaminant release. Comparison of the model and experimental data suggested that a realistic determination of the TSS concentration that can be input into the model was the most critical parameter for predicting air emission rates.     

Development of freshwater sediment management standards for organic matters, nutrients, and metals in Korea

Korean water quality managers are required to promptly develop national assessment standards for freshwater sediment quality due to the Four Major River Restoration Project in Korea in 2009. We conducted this study to develop sediment management standards (SMSs), determining obviously and severely polluted sediment, which could have adverse impacts on water quality and aquatic ecosystem. The SMSs values were derived from the 95th percentile of concentration distribution for organic matter and nutrients in sediment quality database. For the SMSs of metals, foreign sediment quality guidelines (SQGs) were adopted. As a result, 13 % for loss on ignition (LOI), 1,600 mg/kg for total phosphorus (TP), and 5,600 mg/kg for total nitrogen (TN) were set as the SMSs for freshwater sediment in Korea. These values were higher than the range of heavily polluted sediment from USEPA Region 5 guideline derived by the similar approaches for the Great Lakes harbor sediments, and similar or lower than the severe effect level (SEL) from provincial sediment quality guideline (PSQG) of Ontario, Canada by screening level concentration (SLC) approach. However, SMSs in the present study are appropriate considering the concentration ranges and the Korean SMSs’ definition for freshwater sediments in Korea. The Puget Sound marine sediment cleanup screening level (CSL) in Washington State, USA were adopted as the Korean SMSs for As (93 mg/kg), Cd (6.7 mg/kg), Cr (270 mg/kg), Cu (390 mg/kg), Pb (530 mg/kg), and Zn (960 mg/kg) in freshwater sediments. Hg concentration (0.59 mg/kg) of CSL was too low to determine the polluted freshwater sediments in Korea, and the SEL of Ontario, Canada for mercury concentration (2 mg/kg) was selected as the SMS for Hg. These values were found reasonable through the assessment of applicability with the datasets from locations directly affected by obvious point sources. These results indicate that SMSs for organic matter, nutrient, and metals derived within the present study can successfully determine obviously and severely polluted sediment in Korea. However, the SMSs have limits to specifically determine the effects of polluted sediment on water quality and aquatic ecosystem in Korea. Thus, we will revise and specify SMSs considering those effects and further sediment quality assessment framework in the near future.     

Monitoring of PCDD/Fs and dioxin-like PCBs and seasonal variations in mussels from the Mar Grande and the Mar Piccolo of Taranto (Ionian Sea,Southern Italy)

The levels and specific profiles of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in Mytilus galloprovincialis from the Mar Grande and the Mar Piccolo of Taranto were determined during the extensive monitoring plan of Local Health Authority to assess PCDD/Fs and DL-PCBs contamination in food and farm products, within 20 km from the industrial areas of Taranto, between March and December 2011. The average Total Toxicity Equivalence (TEQ) values for the sum of PCDD/F and DL-PCBs ranged from 1.61 to 5.63 pg WHO₂₀₀₅-TEQ g^?1 wet weight basis, with the highest in the first inlet of the Mar Piccolo. In particular, DL-PCBs were the dominant chemicals in all samples, followed by PCDFs and PCDDs. Congener patterns in mussels were similar, indicating a homogeneous behavior in studied areas and, probably, the same type of source. The seasonal concentrations trend showed a relevant increase of dioxin and dioxin-like PCBs TEQs during the summer months, exceeding the limits set by the European Community for food and foodstuff. Reducing PCDD/Fs and PCBs is necessary to decrease contamination levels in order to safeguard marine ecosystem and human health in the Taranto area.