Port Sediments Research Articles

Study of the rheological properties and nautical depth assessment of fine sediments in Iranian ports

Sediments containing more than 10% clay particles by mass can exhibit cohesive properties. Cohesive sediments are commonly found in coastal areas worldwide, including the southern shore of the Caspian Sea and the northern/northwestern beaches of the Persian Gulf. These cohesive sediments can form a layer of soft to extremely soft mud, known as fluid mud, covering the seabed. The study examined the properties of natural mud samples collected from different depths and locations within three Iranian ports: Anzali Port (Caspian Sea), and Khorramshahr and Bushehr Ports (Persian Gulf). The laboratory analyses included determining the sediment grain-size distribution, density, carbonate content, organic matter content, and rheological properties at different water content ratios. Disregarding the impact of variations in organic matter and carbonate contents in the samples, water content ratio was the main factor affecting the rheological properties of sediments.

Sediment organic matter predicts polycyclic aromatic hydrocarbon distribution in port sediments

We evaluated the influence of organic matter in polycyclic aromatic hydrocarbons (PAHs) in port sediments using multiple linear regression (MLR) and prediction models. Total sediment PAHs ranged between 45 and 3230 ng/g dw (average: 557 ± 962 ng/g dw), with PAHs primarily originating from river inputs, confined to areas near the estuaries. Coal/biomaterial combustion and petroleum mainly contribute to the presence of PAHs along estuaries, with medium-high to high ecological risks. MLR TPAHs prediction model included variables, namely, the marine-derived total organic carbon (TOCmar), terrestrial fraction of organic matter (Fterr), and carbon-to‑nitrogen ratio (CNR). Results indicate that mainly marine- followed by terrestrially-derived organic matter influenced sediment PAH distribution. Total organic nitrogen and CNR were variables in the toxic equivalent (TEQ) prediction model, demonstrating that terrestrial pollution sources primarily influenced TEQ. The study analyzes and predicts the impact of organic matter and its sources on the fate and transport of PAHs in port sediments.

Sediment source and dose influence the larval performance of the threatened coral Orbicella faveolata.

The effects of turbidity and sedimentation stress on early life stages of corals are poorly understood, particularly in Atlantic species. Dredging operations, beach nourishment, and other coastal construction activities can increase sedimentation and turbidity in nearby coral reef habitats and have the potential to negatively affect coral larval development and metamorphosis, reducing sexual reproduction success. In this study, we investigated the performance of larvae of the threatened Caribbean coral species Orbicella faveolata exposed to suspended sediments collected from a reef site in southeast Florida recently impacted by dredging (Port of Miami), and compared it to the performance of larvae exposed to sediments collected from the offshore, natal reef of the parent colonies. In a laboratory experiment, we tested whether low and high doses of each of these sediment types affected the survival, settlement, and respiration of coral larvae compared to a no-sediment control treatment. In addition, we analyzed the sediments used in the experiments with 16S rRNA gene amplicon sequencing to assess differences in the microbial communities present in the Port versus Reef sediments, and their potential impact on coral performance. Overall, only O. faveolata larvae exposed to the high-dose Port sediment treatment had significantly lower survival rates compared to the control treatment, suggesting an initial tolerance to elevated suspended sediments. However, significantly lower settlement rates were observed in both Port treatments (low- and high-dose) compared to the control treatment one week after exposure, suggesting strong latent effects. Sediments collected near the Port also contained different microbial communities than Reef sediments, and higher relative abundances of the bacteria Desulfobacterales, which has been associated with coral disease. We hypothesize that differences in microbial communities between the two sediments may be a contributing factor in explaining the observed differences in larval performance. Together, these results suggest that the settlement success and survival of O. faveolata larvae are more readily compromised by encountering port inlet sediments compared to reef sediments, with potentially important consequences for the recruitment success of this species in affected areas.

Pollution Characteristics and Ecological Impact of Screening Analysis of Fishing Port Sediments from Dalian, North China.

Environmental pollution from synthetic chemical mixtures has significant adverse impacts on marine ecosystems. However, identifying the main constituents of chemical mixtures that pose ecological threats is challenging due to the necessity of an integrated workflow for comprehensive identification and toxicological prioritization of pollutants. Here, an all-in-one mass spectrometric strategy integrating target, suspect, and nontarget analysis was used to investigate organic pollutants of concern in fishing port sediments, with 355 pollutants (32 from target analysis, 118 from suspect screening and 205 from nontarget analysis) identified in 11 categories. The chemical classes of polycyclic aromatic hydrocarbons (PAHs), pesticides, and intermediates were the extensively detected chemical classes. The ecological risks of absolutely quantified pollutants (i.e., 16 parent PAHs, 7 organophosphate esters (OPEs), 10 pesticides and 4 benzotriazole ultraviolet absorbers) were assessed using toxicity-weighted concentration ranking, with o,p'-DDT being the major contributor. Under the toxicological priority index (ToxPi) framework, an extended ranking of all identified pollutants was achieved by combining instrument response and detection frequency, with a priority control list of 15 pollutants obtained, of which benzo[ghi]perylene (BghiP) and p,p'-DDE had the highest risk priority. Due to frequent detection rates and significant environmental risks, routine monitoring of petroleum pollutants is considered essential. This study presents a general workflow that includes comprehensive identification and prioritization of pollutants, facilitating chemical management and ecological risk assessment.

Controlling effects of terrestrial organic matter on metal contamination and toxicity risks in port sediments

The contents of metals, total carbon, total nitrogen (TN), total organic carbon (TOC), and stable isotope composition (δ13Corg and δ15N) of sediment organic matter (SOM) were investigated to explore the sources and spatial distribution of metals and SOM in the surface sediments (Kaohsiung Port, Taiwan). Results showed that TOC and metals in estuarine sediments are high, gradually decreasing toward the port entrances. The δ13Corg, δ15N, and TOC/TN ratios indicate that SOM comes mainly from terrestrial sources. This study proposes a befitting model between metal pollution and toxicity risk index and SOM sources in port sediments by combining stable isotope composition, correlation matrix, and multiple linear regression analysis. The model indicates that the degree of metal pollution and toxicity risk in sediments are mainly affected by TOCterr content and SOM source. The results help to understand the influence of organic matter sources in port sediments on metal concentration distribution.

Assessing the ecological risk of heavy metal sediment contamination from Port Everglades Florida USA.

Port sediments are often contaminated with metals and organic compounds from anthropogenic sources. Remobilization of sediment during a planned expansion of Port Everglades near Fort Lauderdale, Florida (USA) has the potential to harm adjacent benthic communities, including coral reefs. Twelve sediment cores were collected from four Port Everglades sites and a control site; surface sediment was collected at two nearby coral reef sites. Sediment cores, sampled every 5 cm, were analyzed for 14 heavy metals using inductively coupled plasma-mass spectrometry. Results for all three locations yielded concentration ranges (µg/g): As (0.607-223), Cd (n/d-0.916), Cr (0.155-56.8), Co (0.0238-7.40), Cu (0.004-215), Pb (0.0169-73.8), Mn (1.61-204), Hg (n/d-0.736), Mn (1.61-204), Ni (0.232-29.3), Se (n/d-4.79), Sn (n/d-140), V (0.160-176), and Zn (0.112-603), where n/d = non-detected. The geo-accumulation index shows moderate-to-strong contamination of As and Mo in port sediments, and potential ecological risk indicates moderate-to-significantly high overall metal contamination. All four port sites have sediment core subsamples with As concentrations above both threshold effect level (TEL, 7.24 µg/g) and probable effect level (PEL, 41.6 µg/g), while Mo geometric mean concentrations exceed the background continental crust level (1.5 µg/g) threshold. Control site sediments exceed TEL for As, while the reef sites has low to no overall heavy metal contamination. Results of this study indicate there is a moderate to high overall ecological risk from remobilized sediment due to metal contamination. Due to an imminent dredging at Port Everglades, this could have the potential to harm the threatened adjacent coral communities and surrounding protected habitats.

Contaminants from dredged sediments alter the transcriptome of Manila clam and induce shifts in microbiota composition

BackgroundThe reuse of dredged sediments in ports and lagoons is a big issue as it should not affect the quality and the equilibrium of ecosystems. In the lagoon of Venice, sediment management is of crucial importance as sediments are often utilized to built-up structures necessary to limit erosion. However, the impact of sediment reuse on organisms inhabiting this delicate area is poorly known. The Manila clam is a filter-feeding species of high economic and ecological value for the Venice lagoon experiencing a drastic decline in the last decades. In order to define the molecular mechanisms behind sediment toxicity, we exposed clams to sediments sampled from different sites within one of the Venice lagoon navigable canals close to the industrial area. Moreover, we investigated the impacts of dredged sediments on clam’s microbial communities.ResultsConcentrations of the trace elements and organic chemicals showed increasing concentrations from the city of Venice to sites close to the industrial area of Porto Marghera, where PCDD/Fs and PCBs concentrations were up to 120 times higher than the southern lagoon. While bioaccumulation of organic contaminants of industrial origin reflected sediments’ chemical concentrations, metal bioaccumulation was not consistent with metal concentrations measured in sediments probably due to the activation of ABC transporters. At the transcriptional level, we found a persistent activation of the mTORC1 signalling pathway, which is central in the coordination of cellular responses to chemical stress. Microbiota characterization showed the over-representation of potential opportunistic pathogens following exposure to the most contaminated sediments, leading to host immune response activation. Despite the limited acquisition of new microbial species from sediments, the latter play an important role in shaping Manila clam microbial communities.ConclusionsSediment management in the Venice lagoon will increase in the next years to maintain and create new canals as well as to allow the operation of the new mobile gates at the three Venice lagoon inlets. Our data reveal important transcriptional and microbial changes of Manila clams after exposure to sediments, therefore reuse of dredged sediments represents a potential risk for the conservation of this species and possibly for other organisms inhabiting the Venice lagoon.

Effects of marine sediment as agricultural substrate on soil microbial diversity: an amplicon sequencing study

BackgroundThe soil microbiota has a direct impact on plant development and other metabolic systems, such as the degradation of organic matter and the availability of microelements and metabolites. In the context of agricultural soils, microbial activity is crucial for maintaining soil health and productivity. Thus, the present study aimed to identify, characterize, and quantify the microbial communities of four types of substrates with varying proportions of marine port sediment used for cultivating lemons. By investigating microbial diversity and relative abundance, the work aimed to highlight the importance of soil microbial communities in agriculture when alternative culture media was used.ResultsThe composition and structure of the sampled microbial communities were assessed through the amplification and sequencing of the V3-V4 variable regions of the 16 S rRNA gene The results revealed a diverse microbial community composition in all substrate samples, with a total of 41 phyla, 113 classes, 266 orders, 405 families, 715 genera, and 1513 species identified. Among these, Proteobacteria, Bacteroidota, Planctomycetota, Patescibacteria, Chloroflexi, Actinobacteriota, Acidobacteriota, Verrucomicrobiota, and Gemmatimonadota accounted for over 90% of the bacterial reads, indicating their dominance in the substrates.ConclusionsThe impact of the substrate origin on the diversity and relative abundace of the microbiota was confirmed. The higher content of beneficial bacterial communities for plant development identified in peat could explain why is considered an ideal agricultural substrate. Development of “beneficial for plants” bacterial communities in alternative agricultural substrates, regardless of the edaphic characteristics, opens the possibility of studying the forced and specific inoculation of these culture media aiming to be agriculturally ideals.

Investigating the presence of organophosphate esters in sediments from a typical fishing port agglomeration in Dalian, North China

The presence of 14 organophosphate esters (OPEs) in surface sediments from a typical fishing port agglomeration in Dalian, North China was investigated for the first time. Tris(2-ethylhexyl) phosphate (TEHP), triphenylphosphine oxide (TPPO), and tris(2-chloroethyl) phosphate (TCEP) dominated 12 detectable OPEs (∑OPEs), with concentrations ranging widely from 0.56 to 352 ng/g (dry weight basis). The ∑OPE levels in sediments varied significantly across fishing harbors of various grades, and within the same grade, highlighting uneven distribution of OPE sources and inputs to harbors. The first- and second-class fishing harbors had higher geometric mean of ∑OPE contents compared to center and natural harbors, reflecting higher OPE pollution in these areas. Although there were significant correlations among the OPE congeners with high detection frequencies, the composition patterns of sediment OPEs varied considerably among fishing ports. The sediments in the center and first-class harbors had higher abundance of non-chlorinated OPEs (non-Cl-OPEs), suggesting heterogeneity in source strength and pollution characteristics of Cl- and non-Cl-OPEs in fishing ports. The distribution of OPEs in sediments was weakly associated with sediment organic carbon, but not socioeconomic variables, indicating complex controlling factors of their distributions in port sediments. The ecological risks of sediment OPEs were evaluated, and while OPE accumulations ranged broadly (7–684 ng/cm2), exposure hazards were negligible. The sediments in first- and second-class fishing harbors, which had greater OPE accumulation, were identified as reservoirs of OPEs in port aquatic environments.

Comprehensive assessment of metals and organic pollutants in pelagic fishing port sediments

Fishing ports are among the environments that accumulate pollutants along the coast but often lack environmental data and scientific research. This study investigated 8 metals, 16 polycyclic aromatic hydrocarbons (PAHs), 10 phthalate esters (APs), and 2 alkylphenols (APs) in the surface sediments of Qianzhen Fishing Port, the largest pelagic fishing port in Taiwan. Indicator compounds, pollution hotspots, potential ecological risk levels, and pollution sources were evaluated. Results showed that copper, zinc, and bis(2-ethylhexyl) phthalate (DEHP) in surface sediments were pollution indicators posing potential toxicological risks. Metals and PAHs in sediments were mainly from ship-related sources, while PAEs and APs were related to dockland activities. Combining metal and organic pollutants, the sediments had a moderate potential ecological risk, with metals higher than organic pollutants. Cluster analysis and color geographic map of risks indicate sediment pollution hotspots and areas requiring immediate intervention. In the future, sustainable operation and management can be carried out by using metal-free antifouling paint, improving sewage treatment rate, and regular environmental dredging of fishing port.

Metabolomic Approach to Study the 'Purple Queen' Pomegranate Cultivar Response to Alternative Culture Media and Phenological Stages.

The increasingly evident threat of depletion of world peat bogs is encouraging the search for and study of alternative agricultural substrates that can fully or partially replace peat, guaranteeing food supply (quality and quantity). On the other hand, the identification of the potential for the reuse of waste from relevant economic activities has increased in recent years, mainly motivated by the change to a sustainable circular economy, as is the case of port sediments. Taking into account that significant volumes of dredged port sediments are generated annually so that ports can maintain their economic activity, it is necessary to find objective, sustainable and safe reuse alternatives. In this sense, the objective of this study was to study the response of the "Purple Queen" pomegranate when grown with dredged port sediment. For this, the fruit production (kg), number of fruits (fruits tree-1), fruit weight (g), and seed yield (%) aiming to verify the correct tree development were evaluated. In addition, a 1H-NMR foliar metabolomic study for the three most relevant phenological phases was performed (flowering, fruit development, and post-harvest) to identify metabolic changes in trees. In total, 29 metabolites were identified; among them, 11 were amino acids, 6 organic acids, 5 sugars, and 7 secondary metabolites. The good agronomical development of the trees and fruits indicated the potential for using the dredged sediment as an agricultural substrate. On the other hand, the results revealed that the greatest variability in the metabolomic study occurred between the phenological phases and a lower variability is explained by the substrates used.

Response of macrofaunal assemblages to different pollution pressures of two types of ports

Pollution status and benthic ecological quality of the two types of ports were assessed based on heavy metals and macrofaunal assemblages. Macrofaunal abundance and biomass in the industrial port were significantly higher than those in the fishing port. The dominant species of the two ports were Echinocardium cordatum and Nephtys oligobranchia. The AZTI marine biotic index (AMBI), multivariate AMBI, and Shannon-Wiener diversity index demonstrated that the benthic ecological quality of the two ports was moderate to good. The benthic ecological quality of the distant port sites was better than those of the nearby port sites. The geoaccumulation index and the Hakanson potential ecological risk index indicated that mercury posed a serious threat to port sediment pollution. AMBI, multivariate AMBI, and Shannon-Wiener diversity index were not good indicators for heavy metal pollution. The dominant species and Pielou’s evenness index were significantly correlated with heavy metal pollution and were good biological indicators.

Life Cycle Assessment (LCA) of Substrate Mixes Containing Port Sediments for Sustainable 'Verna' Lemon Production.

The increase in maritime trade and its global economic importance have forced port management actors to carry out the periodic dredging of their sediments to maintain an adequate depth for the passage of large ships to maintain their operation and competitiveness. During the dredging process, large volumes of port sediment are generated. Dredged port sediment is currently considered a waste material and its disposal is regulated. Finding ways to safely reuse port sediments is necessary for sustainable development. In this study, a life cycle assessment (LCA) methodology was applied to identify the environmental impact of port sediments when used as a culture medium for lemon trees. A total of 90 lemon trees (Citrus limon L. Burm var ‘Verna’) were used in the trial. The trees were grown under controlled conditions using three substrates, with different portions of peat and port sediment (25%, 50%, and 75%) to identify the real impacts of the culture media on the growth process. The LCA was calculated and analyzed according to the ISO 14040:2006 standard, using the SimaPro v. 9.3 software (PRé Sustainability B.V, Amersfoort, The Netherlands). The functional unit defined for the three-culture media was 1 kg of lemons. The LCA results showed a significant increase in the environmental impact of lemon cultivation proportional to port sediment content (75%), due to the decrease in fruit production caused by the sediment. However, the least impact was identified for the culture medium at 50% peat and 50% port sediment. The greatest impacts were more related to crop management rather than the port sediment content. The results showed that the use of the port sediment, mixed with other substrates as an agricultural medium amendment, is a viable option for lemon growers.

Mobility of trace metals and microbiological pollution from dredged sediments to the Gulf of Gabes, Tunisia.

Sediments are periodically dredged from the major ports in the Gulf of Gabes (GG) during maintenance operations. These sediments are dumped near the coats of Sfax and Gabes cities. In the present study, 6 trace metals (Cd, Cu, Cr, Ni, Pb, and Zn) concentrations were assessed in both sediments and column water taken from the different basins of Sfax port. This study is the first to focus on the microbial and microalgae contaminations of Sfax port sediments. The spatial distributions of trace metals in dredged sediments from the different basins of Sfax port show that the maximum concentrations of Cd (13.75µg/g), Cu (892.5µg/g), and Zn (1447µg/g) exceeded the Geode standard thresholds. The same elements, also detected in the water column, exceeded the toxicity thresholds for phytoplankton, shellfish, and algae (Cd 0.095µg/l, Cu 4.52µg/l, and Zn 37µg/l). The presence of coliforms, indicators of sewage pollution, as pathogenic germs (Pseudomonas), was shown through microbiological examinations of the sediments and water column. The microalgae enumeration showed the abundance of dinoflagellate cysts (stressed form) which attests to the presence of severe conditions in Sfax port. Different toxic species were identified as Prorocentrum lima and Alexandrium minutum. The same trace metal sources and abundance in Sfax port and GG sediments suggest the hypothesis of their transfer from their disposal sites in coastal areas to deeper depths in the GG and until Boughrara lagoon (BL). As trace metals, microalgae species were also transferred by hydrodynamic currents inside the GG where they found suitable conditions to their proliferation causing the seawater coloration phenomenon, eutrophication, and degradation of the aquatic system.

Assessment and geographical prediction of sediments origin based on hydrocarbons content: application to the Gulf of Aqaba and Port of Tripoli

ABSTRACT In this study, quantitative and qualitative chromatographic analysis for the content measurements of sediments collected from the Gulf of Aqaba/Jordan-Red Sea and Tripoli Port/Lebanon-Mediterranean Sea, were carried out. Sediment hydrocarbon contents were examined by GC-FID. The outcomes showed that 16 hydrocarbons were quantified and identified. Dotriacontane, tritriacontane, hentriacontane, octacosane, heptacosane, pentatriacontane, docosane, tetracosane, and hexatriacontane displayed the major contents at the Gulf of Aqaba. Regarding Tripoli Port sediments; nonacosane, pentatriacontane, pentacosane, dotriacontane, heptacosane, docosane and tetratriacontane were detected. GC-FID data were exposed to PCA and HCA to reveal: the variations of sediment chemical profiles as a result of geographical areas, to show the hydrocarbons that were responsible for clustering, and finally, to facilitate the future profile prediction and areas clustering of unknown sediments based on their chemical profile. By HCA and PCA, the six sediment-origin samples of Aqaba were classified into three clusters; Industrial area alone due to the distinct content of dotriacontane, tritriacontane, hentriacontane and octacosane, Central Power Station, Tala Bay and Hotel Areas in one cluster which was related to the close content of heptacosane and finally the National Tourist Camp and Marine Science in one cluster since they have pentatriacontane with close levels. Regarding Tripoli Port sediment samples, the two clusters revealed that the Current Waste Dump along with the Wastewater Treatment Plant were grouped together, where the Fishing Port, Tripoli Harbour and the Closed Waste Dump areas were clustered in one group. Nonacosane and pentatriacontane were dominant to separate the Tripoli Harbour, Fishing Port area and the Closed Waste Dump, where pentacosane, dotriacontane, heptacosane, docosane and tetratriacontane were responsible to isolate the Wastewater Treatment Plant and the Current Waste Dump together. Classification of sediments based on GC-FID profile will accelerate the future profile prediction and origin-clustering of unknown sediment based on their profile.

Leaching Remediation of Dredged Marine Sediments Contaminated with Heavy Metals

There are more than 150 ports in China and a considerable proportion of dredged sediments in ports and waterways are contaminated with heavy metals as the typical contaminants. It is mandatory to remediate the contaminated dredged sediments prior to further resource utilization. The over-arching objective of this study was to use natural organic acids (oxalic acid, citric acid, tartaric acid, and malic acid) as leaching agents to remove heavy metals (Cu, Cd, and Pb) from contaminated dredged sediments. Batch experiments were conducted to investigate the factors governing the removal rate of heavy metals and leaching kinetics. Citric acid had the best leaching effect on heavy metals Cu, Cd, and Pb with an optimal leaching concentration of 20 mmol/L and a solid-to-liquid ratio of 1:20. The average removal rates of Cu, Cd, and Pb were 85%, 73%, 56%, and 35% for citric acid, malic acid, tartaric acid, and oxalic acid, respectively. The leaching kinetics showed that the removal of heavy metals increased rapidly with time and then gradually reached the maximum value which was best described by the Elovich equation model. The outcomes of this study suggest that citric acid is an effective and environmentally friendly leaching agent for removing heavy metals from marine dredged sediments.

Impacts of Fishing Vessels on the Heavy Metal Contamination in Sediments: A Case Study of Qianzhen Fishing Port in Southern Taiwan

Routine maintenance of fishing vessels and wastewater discharges are primary sources of heavy metals in fishing ports. Sediment pollution assessment is necessary in fishing port management, including sediment dredging and disposal, sewage treatment facility construction, and pollution source control. In this study, sediment heavy metal contents in Qianzhen Fishing Port, the largest pelagic fishery port in Taiwan, were investigated to assess the contamination levels and related potential ecological risks using multiple sediment pollution indices. Normalization methods were applied to identify the potential sources of heavy metals in fishing port sediments. Results showed that Cu, Zn, Pb, and Cr contents in the sediments of the inner fishing port (averages of 276, 742, 113, and 221 mg/kg, respectively) were 3–5 times greater compared to those along the port entrance and outside, indicating the strong impacts of anthropogenic pollution (EFCu: 5.6–12.5; EFZn: 2.8–4.3; EFPb: 2.4–5.4; EFCr: 1.1–3.2). Copper pollution was more severe, with high maxima contamination factor (CFCu: 15.1–24.8), probably contributed by copper-based antifouling paints used in fishing vessels. The sediments in the inner fishing port are categorized as having considerable ecological risk and toxicity (mERMq: 0.61–0.91; ΣTU: 7.5–11.7) that can potentially cause adverse effects on benthic organisms. Qianzhen Fishing Port sediments can be characterized as high Cu/Fe and Pb/Fe, moderate Zn/Fe, and high total grease content, indicating that the potential sources of heavy metals are primarily antifouling paints and oil spills from the fishing vessels. This study provides valuable data for pollution control, remediation, and environmental management of fishing ports.

Butyltin Contamination in Fishing Port Sediments after the Ban of Tributyltin Antifouling Paint: A Case of Qianzhen Fishing Port in Taiwan

This study investigated the concentrations of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in the sediments of the Qianzhen Fishing Port (Taiwan) in 2020. Further, the pollution status, composition, and potential ecotoxicity of BTs were evaluated. This case study provides a reference for the benefits of the ban of TBT-based antifouling paint to date. Results showed that the total butyltin (ΣBTs, sum of TBT, DBT, and MBT) concentrations measured in the sediments of the Qianzhen Fishing Port ranged between 14.2–807 ngSn·g−1 dw, with an average of 356 ± 305 ngSn·g−1 dw. TBT was the most dominant species, with an average concentration of 303 ± 287 ngSn·g−1 dw. This average TBT concentration is about 4.3 times lower than in 2003, showing the progress of gradual degradation of TBT in the sediments. Still, the degradation is rather slow, with a half-life of about 8.09 years. An analysis of the effects of TBT on organisms in the sediments of the Qianzhen Fishing Port was carried out according to the TBT toxicity guidelines of the US Environmental Protection Agency and the assessment class criterion for imposex (ACCI) of the Oslo and Paris Commission (OSPAR). The results showed that TBT levels in 80% of the sediments may pose negative effects on sensitive gastropods, and half of the sediments may even have an impact on gastropod reproduction. These show that marine life is still affected and threatened by TBT compounds, despite the decline of TBT concentrations since the ban of TBT-containing antifouling paints on ships in 2008. Therefore, it is necessary to continue paying attention to the changes of TBT concentrations and their potential ecological risks in the marine environment, and to formulate TBT management plans and strategies to mitigate their impacts in marine ecosystems.

Reuse of harbour and river dredged sediments in adobe bricks

Dredged sediments from ports and rivers are treated as waste material. The disposal of waste sediments has environmental concerns and requires financial resources. Dredged sediments reuse in building material such as adobe bricks can provide an alternate solution to valorize and handle this waste material. Adobe bricks are eco-friendly construction materials manufactured with clayey soil and fibers. Natural fibers addition improves mechanical and thermal characteristics of adobe bricks.In this research, a pilot study was conducted to manufacture adobe bricks from harbor dredged sediments and replicate the procedure to manufacture adobe bricks for river dredged sediments. Harbor sediments were taken from Dunkirk port, France. The physical and chemical characteristics of these sediments were analyzed. Sediments suitability for adobe bricks with grains size and Atterberg limit was discussed with different approaches. Bricks were manufactured by mixing Dunkirk sediments and saturated hemp shiv at different hemp shiv content. Sediments and fibers were mixed with a mortar mixer and molded into specimens of 4*4*16 cm3. Dynamic compaction was opted to compact the bricks. Drying of bricks was done in the oven at 40 °C. Finally, sediments mixing, molding and compaction procedures were derived and problems encountered during were discussed.The procedure derived from Dunkirk sediments was implemented on Usumacinta River sediments to make adobe bricks with the addition of palm oil flower fibers (POFl). Characteristics of Usumacinta River sediments and palm oil flower fibers were found to use in adobe bricks. Palm oil flowers fibers were cut with a knife mill of grid-2 cm and grid-3 cm. Dunkirk sediments bricks manufacturing process was repeated to make bricks from Usumacinta sediments.Laboratory scale manufacturing and testing of bricks from Dunkirk port sediments and Usumacinta River sediments allows to observe the valorization of dredged sediments in adobe bricks with mechanical perspectives. In this study, properties of bricks manufactured by both harbor and river dredged sediments such as tensile strength, toughness and fibers distribution inside the bricks were studied and compared.

Effect of Phytoremediated Port Sediment as an Agricultural Medium for Pomegranate Cultivation: Mobility of Contaminants in the Plant

Although the dredging of ports is a necessary management activity, it generates immense quantities of sediments, that are defined by the European Union as residues. On the other hand, the relevant peat demand for plant cultivation compromises its availability worldwide. In this context, the present work wanted to find an alternative substrate in order to replace and/or reduce the use of peat in agriculture, through the study of the suitability, concerning the exchange of substrate–plant–water pollutants, of the dredged remediated sediments as a fruit-growing media. Forty-five pomegranate trees (Punica granatum L. cv “Purple Queen”) were cultivated in three types of substrates (100% peat as a control, 100% dredged remediated sediments and 50% both mixed). The metal ion content and pesticide residues were analysed in the different plant parts (root, stem, leaves and fruits) and in drainage water. The results showed a limited transfer of pollutants. All the pollutants were below the legal limits, confirming that the dredged sediments could be used as a growing media, alone or mixed with other substrates. Thus, the results point out the need to open a European debate on the reuse and reconsideration of this residue from a circular economy point of view.