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The spatial distribution of total petroleum hydrocarbons (TPH) were analysed in the seawater and sediment samples collected from 27 locations along the Southeast coast of India. A first-time assessment was carried out on the distribution of TPH in both water and sediments for the entire coastline of Tamil Nadu. The concentration of TPH in seawater showed large spatial variation ranging from below detection level (BDL) to 47.5 μg/L and 0.01 to 53.12 μg/L in the surface and bottom waters, respectively. TPH levels exceeded the regulatory limits specified by FAO, China's Marine Monitoring Standards and the European Community in the seawater samples of Thoothukudi harbour (S2 station). The results showed that seawaters of southern stations were comparatively more polluted with TPH. TPH values in sediment were between 2.33 and 30.07 μg/g, and their levels remained below the Marine Sediment Quality Standard (500 μg/g). The spatial profile of TPH in sediments were contrasting to that observed for seawater. Higher TPH values were observed in sediments of the northern region than southern. TPH contents are strongly correlated with clay (R2 = 0.776; P < 0.001) and silt (R2 = 0.648; P < 0.001); conversely, there is a significant negative correlation between TPH and sand (R2 = 0.753; P < 0.001). ANOVA analysis demonstrated a significant difference (F = 11.75; p < 0.01) between the TPH concentrations of water and sediments. Non-metric multidimensional scaling (nMDS) was performed to determine the similarity among sampling stations that formed five crusted groups. Sediment along the southeast coast can be categorised as slightly polluted with respect to TPH as per the ATSDR standards. [ABSTRACT FROM AUTHOR]

Purpose: The environmental quality standards (EQSs) were defined by the Water Framework Directive (2000/60/EC) and daughter directives for hindering the chemical pollution of surface water bodies. For substances with poor solubility in water and/or the tendency to bioaccumulate along the food chain, member states could choose to define the EQSs on sediments and marine organisms if they guarantee the same level of protection of the EQSs derived for water. Also, Italy defined them on sediments without considering harbors because of their role as pressure sources. Considering the available environmental information, this study focused on verifying the applicability and possible limits of the EQSs in sediments from different Italian harbors. Materials and methods: A dataset with concentrations of metals and trace elements (MTEs) and organic compounds (OCs) from the sediments of 34 Italian harbors was assessed. Grain size parameters were also included for complete information on sediment characteristics. Data were processed through univariate statistics to identify the position of the EQSs within the whole distribution of concentration values. Moreover, a logistic model was applied to verify the probability of exceeding the EQSs for at least one parameter (susceptibility) in the harbor areas. Results and discussion: The EQSs of all MTEs were found close to the overall medians, demonstrating that they are suitable values for highlighting widespread metal contamination, also recognizable in the output of the logistic model, where wide areas with a homogeneous susceptibility were highlighted. The EQSs of most OCs resulted considerably higher than the overall medians, but a minor part of the data exceeded them by far, demonstrating that the contamination was characterized by patchy distribution, as also shown by the susceptibility maps. Conclusions: Applying a statistical approach, this study tried to compare the distribution of concentration data with the EQSs of sediments based on a specific dataset containing many records from many Italian harbors. The logistic model applied in this study, based on the excess of the EQSs for at least one parameter, represented a robust tool to define areas at high susceptibility in the harbors and confirmed their adaptability also in these highly impacted areas. [ABSTRACT FROM AUTHOR]

The study was performed in the Republic of Panama. Panama has a coastline of 2,988.3 km, of which 1,700.6 km corresponds to the Pacific coast. Most of the coast is flat, and several geomorphological features characterize the Panamanian coastal sector, such as the Gulf of Montijo, which is located towards the west of the Panamanian Pacific coast in the province of Veraguas. The Gulf is a remarkable ecosystem of mangroves well preserved and internationally recognized as a Ramsar area. It represents the buffer zone of Coiba Island (Coiba National Park). Sixteen sampling stations were established along the coast to analyze the vertical and spatial variability of physical and chemical parameters (temperature, salinity, dissolved oxygen, pH, and conductivity). The quality of unexposed marine sediment was evaluated in four samples from the western sector of the Gulf of Montijo. The marine sediment samples were collected with a Dietz-LaFond Snapper dredge, between 1.5 and 3.0 m depth. Physical and chemical observations and marine sediment sampling were carried out during high tide +4 to low tide +3, in negative syzygy phase tide. The analysis of the oceanographic conditions, especially the physical and chemical properties of the water along with the longitudinal profile, showed a conservative distribution increasing gradually towards the outer region in an approximately linear way due to the dilution and mixing processes, both in the surface layer and at the bottom, and a not very developed vertical gradient, with slight stratification. The results of heavy metal analyses in marine sediments report high cadmium concentrations along the west coast, with concentrations above the limit levels of the Canadian marine sediment quality guidelines. The study area requires continuous monitoring that is representative of seasonality (dry, intermediate, and rainy periods), including a more significant number of stations since it is evidence of an affectation of the environmental quality of the marine ecosystem due to possible anthropogenic activities. [ABSTRACT FROM AUTHOR]

Evaluating the elemental composition of sediment cores is essential for understanding environmental changes, including depositional variations, soil formation processes, and human influences. Such investigations offer insights into the biological, geochemical, and industrial impacts on sediment quality and the health of marine ecosystems. This study evaluates the pollution levels and their sources along the coast of Karachi, Pakistan, as well as the effects of pollution on human and ecological health. The core sediment's elemental composition was determined by Neutron Activation Analysis. The mean values in mg/kg of the elements are Al (34800), As (11.15), Ba (371), Br (18.40), Ca (118850), Ce (41.43), Co (10.29), Cr (62.41), Cs (5.27), Eu (0.80), Fe (22855), Hf (2.43), K (11210), La (20.84), Lu (0.26), Mg (21750), Mn (416), Na (8350), Nd (18.92), Rb (66.35), Sb (1.04), Sc (8.31), Se (8.23), Sm (3.88), Sn (17.05), Ta (0.77), Th (7.17), U (3.96), V (71.80), Yb (1.28) and Zn (581). Various pollution indices were used to assess the pollution level of these elements in the sediment core. Statistical tools like Pearson's correlation matrix and Factor analysis were utilized for source apportionment of these elements. Source apportionment showed the sources of heavy metals and rare earth elements are Ship breaking facilities, different types of refuse effluents carried by the Malir river into the sea and the geology of the area. Carcinogenic and non-carcinogenic health hazards associated with exposure to toxic metals were also calculated. The ecological risk factor and sediment quality index showed As and Zn may harm the marine environment. In conclusion, this study found that the sediment of Karachi's coast is polluted with high levels of As, Br, Ca, Cr, Sn, and Zn; with As, Cr and Zn posing a threat to the marine ecology as well as human health. [Display omitted] • NAA was used to quantify elemental composition of sediment from Karachi. • Pollution sources identified: Industrial effluents and ship breaking facilities. • Total lifetime cancer risk for As and Cr exceeds US-EPA standards for children. • Potential harm to marine ecosystem from As, Cr, and Zn. [ABSTRACT FROM AUTHOR]

The assessment of the sediment quality and degree of contamination of El-Dabaa region along the Mediterranean coast, which comprises an area selected for developing a nuclear power plant (NPP) in Egypt, is important to provide background contaminant levels of coastal sediments. Determination of 21 heavy metals concentrations (Th, U, Na, Mg, Al, K, Ca, V, Ag, Sb, Mo, Co, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), and geochemical analysis of bottom sediments collected from five selected stations along El-Dabaa area were studied. Contamination factor indices have been applied. Results of the correlation between the five stations reveal insignificant variations reflected homogenous environment, associated with similar terrestrial inputs and hydrodynamic systems. Grain size texture dominated by fine sand, suggested an active depositional process, influenced by longshore sediment transport, corresponding to the magnitude of wave energy. Sediments are characterized by carbonates structure, with significant high calcium carbonate, mainly pure oolitic carbonate, consistent with high Ca metal concentration, corresponding to the geologic composition of hydrographic basins, influenced by the carbonate natural geogenic sources of the area. Low total organic matter content is related mainly to the semi-arid climate of the region, the absence of Nile river input, and the strong hydrodynamic effect. In General, concentrations of heavy metals were low compared with the eastern Mediterranean coast of Egypt, it verified below the threshold effects level according to international sediment quality guidelines. The contamination factor reveals a high degree of Ag and Sb, anticipated to be traced from dense mining and rock processing activities nearby El-Dabaa region in the Western Desert. [ABSTRACT FROM AUTHOR]

(1) Background: As the chemical and physicochemical properties of marine sediments are closely related to natural and anthropogenic events, it is a real challenge to use their specific assessment as an indicator of environmental pollution discharges. (2) Methods: It is addressed in this study that collection with intelligent data analysis methods, such as cluster analysis, principal component analysis, and source apportionment modeling, are applied for the assessment of the quality of marine sediment and for the identification of the contribution of pollution sources to the formation of the total concentration of polluting species. A study of sediment samples was carried out on 174 samples from three different areas along the coast of the Varna Gulf, Bulgaria. This was performed to determine the effects of pollution. As chemical descriptors, 34 indicators (toxic metals, polyaromatic hydrocarbons, polychlorinated biphenyls, nutrient components, humidity, and ignition loss) were used. The major goal of the present study was to assess the sediment quality in three different areas along the Gulf of Varna, Bulgaria by the source apportionment method. (3) Results: There is a general pattern for identifying three types of pollution sources in each area of the coastline with varying degrees of variation between zone A (industrially impacted zones), zone B (recreational areas), and zone C (anthropogenic and industrial wastes). (4) Conclusions: The quantitative apportionment procedure made it possible to determine the contribution of each identified pollution source for each zone in forming the total pollutant concentrations. [ABSTRACT FROM AUTHOR]

BACKGROUND: The contamination of arsenic and mercury in intertidal sediments will lead to excessive levels of arsenic and mercury in the flora and fauna of the region, which will seriously affect the ecological environment of local vegetation and further affect the survival and safety of human beings. Therefore, it is of great practical significance to study the changes in the contents and spatial distribution of arsenic and mercury in intertidal sediments. OBJECTIVES: To investigate the contents of arsenic and mercury in sediments, so as to provide basic information on the pollution of arsenic and mercury in intertidal sediments. METHODS: The contents of arsenic and mercury in the sediments of the study area were determined by atomic fluorescence spectrometry (AFS), and iron was selected as the normalized element to establish the environmental background values of arsenic and mercury elements in different intertidal sediments. The geoaccumulation index method and potential ecological hazard index method were used to evaluate the pollution status of arsenic and mercury in the study area. RESULTS: Background value of arsenic content: Minjiang Estuary (2. 90mg / kg)

Comprehensive spatial and temporal data on sediment quality in the Adriatic Sea are lacking. Therefore, prior to planned anthropogenic interventions in the local marine environment, such as deepening of the Rovinj harbour, the results of physicochemical and ecotoxicological analyses of five local coastal sediments were compared with regional averages and SQGs of neighbouring countries. Analyses of sediment grain size, content of metals and heavy metals, PAHs and PCBs were performed according to standard protocols. Sediment quality was classified according to French legislation (N1 and N2 level) and sediment guidelines. The phytotoxicity of the eluates was studied by flax seed germination tests. The logistic regression models Pmax and Pavg were used to estimate the probability of toxic effects. Except for the open sea (S5), all other sediments had concentrations slightly higher than the N1 for some metals (Cu, Ni, Hg, Cr) or ΣPAHs, while the Rovinj harbour (S1) reached the N2 value for mercury. The phytotoxicity assay with sediment eluates showed inhibition of germination, root length and root biomass production, with an average phytotoxicity index (PI) ranging from 6.06% to 42.00%. Significant correlations of Pavg and Pmax values with phytotoxicity and other specific parameters were found. In general, according to the applied SQGs, there are no potential ecological impacts on the marine environment at any of the investigated sites, with the exception of site S1. [ABSTRACT FROM AUTHOR]

Mangrove forests are sources and sinks for various pollutants. This study analyzed the current status of heavy metal and arsenic (As) pollution in mangrove surface sediments in rapidly industrializing and urbanizing port cities. Surface sediments of mangroves at Wulishan Port on the Leizhou Peninsula, China, were analyzed using inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) for the presence of Cr, Pb, Ni, Zn, Cd, Cu, As, and Hg. The Pollution load index, Nemerow pollution index, and Potential ecological risk index were employed to evaluate the pollutant. Multivariate statistical methods were applied for the qualitative analysis of pollutant sources, and the APCS-MLR receptor model was used for quantification. This study indicated the following results: (1) The average content of eight pollutants surpassed the local background level but did not exceed the Marine Sediment Quality standard. The pollution levels across the four sampling areas were ranked as Ⅲ > Ⅳ > Ⅰ > Ⅱ. The area Ⅱ exhibited relatively lower pollution levels with the grain size of the sediments dominated by sand, which was not conducive to pollutant adsorption and enrichment. (2) The factor analysis and cluster analyses identified three primary sources of contamination. As, Cr, Ni, and Pb originated from nearby industrial activities and their associated wastewater, suggesting that the primary source was the industrial source. Cd, Cu, and Zn stem from the cement columns utilized in oyster farming, alongside discharges from mariculture and pig farming, establishing a secondary agricultural source. Hg originated from ship exhaust burning oil and vehicle emissions in the vicinity, representing the third traffic source. (3) The APCS-MLR receptor model results demonstrated industrial, agricultural, and traffic sources contributing 47.19 %, 33.13 %, and 13.03 %, respectively, with 6.65 % attributed to unidentified sources. • Pollution and ecological risks were evaluated, with area ranking obtained as Ⅲ>Ⅳ>Ⅰ>Ⅱ. • FA and CA qualitatively identified pollutant sources, and APCS-MLR quantified them. • Analyses suggest industrial, agricultural, and traffic as main pollution sources. • APCS-MLR model shows industrial (47.19 %), agricultural (33.13 %), and traffic (13.03 %). [ABSTRACT FROM AUTHOR]

The Haizhou Bay in eastern China, for a long time, is seriously polluted with heavy metals (HMs) due to intensive anthropic pressure. The river runoff is the dominant pathway of HM transport in the coastal region. However, the information on HM pollution in coastal rivers flowing into Haizhou Bay was still limited, and potential risks and possible sources raised by HMs in this area were neglected up to now. To fully understand the distribution and ecological risks of sediments in seven rivers along the bay, surface sediments were collected and seven HMs (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) were investigated. The results showed that HM concentrations generally met the primary standard criteria of China (marine sediment quality), except for Cu and Zn. On the other hand, Zn and Cu tended to exhibit probable adverse biological effects in the Shawang River comparison with some sediment quality guidelines (SQGs). Moreover, the enrichment factor and geo-accumulation index demonstrated that there was no or slight contamination to be found for Cr, Mn, Ni, Cu, Zn, and Pb and moderate pollution for Cd. The contamination factor (Cfi), integrated contamination degree (CF), modified degree of contamination (mCd), and modified pollution index (MPI) revealed individual metal contamination in localized areas. In these river sediments, the potential ecological risk (RI) was low to moderate, except Cd posted a considerable ecological risk because of its high enrichment. Furthermore, the Shawang River and Linhong River were seriously polluted with HMs among seven rivers. These results provided a new direction for controlling HM pollution in Haizhou Bay which suggested substantial measures should be implemented to alleviate the potential risk of HMs, to these rivers sediments. [ABSTRACT FROM AUTHOR]

Six heavy metals (As, Cu, Cd, Zn, Cr, and Pb) in surface sediments (0–5 cm) from the twenty selected sites of the coastal Pearl Bay (South China Sea) were analyzed to assess the distribution pattern and potential ecological risk. Overall concentrations (mg/kg, dw) in the sediment samples were: As (10.88 ± 6.50), Cu (24.16 ± 18.63), Cd (0.55 ± 0.78), Zn (48.53 ± 30.06), Cr (35.78 ± 28.66), Pb (31.28 ± 18.50). Results showed that the overall mean values of Cd concentrations exceeded the standard of China Marine Sediment Quality, caused by significantly high levels of Cd contents in five sites (S8, S11, S13, S16, and S17) at the offshore area of Pearl Bay. Generally, the metal concentrations showed a decreasing trend from the offshore area to the inner bay. Various index values such as the geo-accumulation index (Igeo), the ecological risk index (Eri), and the contamination factor (CF) demonstrated that the coastal Pearl Bay was not polluted by the examined metals except for Cd, which might cause contamination and ecological risk in the region. Principal component analysis (PCA) results indicated that Cu, Zn, and Cr might originate from natural sources inland, and Pb and As might come from the gasoline and diesel fuel from engine boats. It is recommended that further research should focus on detecting the acute source and transferring mechanisms of the toxic metal Cd. [ABSTRACT FROM AUTHOR]

Estuarine sediment quality is highly associated with anthropogenic activities in watersheds. This study attempts to couple socioeconomic patterns with estuarine sediment quality via legacy organochlorines in 14 Chinese coastal watersheds. Sedimentary concentrations of HCHs, DDTs, and PCBs showed a significant spatiality in estuary, up to 48.7 ± 15.1, 89.0 ± 46.4, and 54.5 ± 17.2 ng g−1, which were predominated by β-HCH, p,p′-DTs, and tri- to penta-PCBs, respectively. Ecological risk of organochlorines was negligible except few moderate risks for DDTs and PCBs against the first class quality of the marine sediment quality guidelines of China. Sedimentary DDT and PCB concentrations were significantly delineated by an environmental Kuznets curve model as a function of non-agricultural GDP per capita in watersheds, while HCHs by an increasing linear model. Findings of this study provide a tool to quantify the contribution of anthropogenic development in watershed to environmental change in estuary across the world. [ABSTRACT FROM AUTHOR]

In this study, a total of 26 surface sediments samples are collected from the Liao River estuary wetland, China. The concentration, potential ecological risk, and source apportionment of potentially toxic metals including Sr, Zn, Cr, Ni, Pb, Cu, and As in different seasons are analyzed. The average concentrations of potentially toxic metals are below the first class of Chinese marine sediment quality standard. There is no significant difference in the concentrations of potentially toxic metals in the sediments collected in June and November. The concentrations of potentially toxic metals in the periphery of the nature reserve are higher than those in the core area of the nature reserve. The average enrichment factors of As, Pb, Cu, Ni, Zn, and Cr are about 1, classified as minimal enrichment. The average enrichment factor of Sr is >2, which corresponds to moderate enrichment. The individual (Er) and total potential ecological risks (RI) of potentially toxic metals are low. The positive matrix factorization model suggested that the potentially toxic metals in surface sediments in June are dominantly from atmospheric deposition, industrial discharges, natural sources, and traffic emission. However, the traffic emission source is replaced by agricultural production and metal smelting activities in November. [ABSTRACT FROM AUTHOR]

The present study emphasised the speciation and mobility of heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in sediments of the Yundang Lagoon catchment (YLC) at Xiamen in China. The maximum total metals concentrations of Cr, Cu, Zn, Cd, and Pb were higher than the class I pollution level of China Marine Sediment Quality values. Average total metals concentrations of Cu, Zn, Cd, and Pb were greater than world average shale values. The highest average percentages of Cr (68.01%), Mn (39.14%), Ni (61.32%), and As (74.09%) were found in the residual fraction, while Cu (50.69%) was the highest in the oxidisable fraction. Furthermore, the greater percentages of Zn (37.65%), Cd (48.98%), and Pb (47.52%) were bound in the reducible forms in YLC sediment. Total organic carbon (TOC) showed a strong correlation with heavy metal fractions, suggesting that TOC could be a carrier of heavy metals within alkaline urban sediment. The risk assessment code values for Cd, Mn, and Zn indicate that these metals could pose a medium to a high potential risk to the aquatic organisms. However, the present remediation strategy should be continued with more focus on reducing urban runoff and domestic discharge into the lagoon. [ABSTRACT FROM AUTHOR]

The Huangmao Island dumping area is adjacent to the Pearl River Estuary in the South China Sea. From its first dumping activity in 1986 to 2017, 6750 × 104 m3 dredged materials were dumped in this dumping area. Sediment pollution levels, ecological risk, and benthic communities in 2011–2017 were evaluated; the results showed that the concentrations of the heavy metals (HMs; except Hg) in surface sediments of the dumping area met the class I standard of marine sediment quality (GB 18668-2002). HMs in the surface sediments were relatively high in the northern and central areas but relatively low in the south of the dumping area. Speculation was that the spatial variation in HM concentrations might be caused by dumping activities. The Nemerow index implied that the contaminated area was mainly in the north of the dumping area (S1, S2, and S3), where the dumping amount was the largest. The potential ecological risk (Eir) indices of Zn, As, Cu, and Pb indicate that these metals posed a low risk to the ecosystem of the dumping area, whereas Cd and Hg posed a high risk at some stations. The geoaccumulation indices (Igeo) of Zn, As, Cu, and Pb specified no pollution or light pollution in the study area, whereas those of Cd and Hg in most years indicated mild contamination levels. Benthic organisms in the study area were arthropods, chordates, annelids, mollusks, echinoderms, nemertinean, coelenterate, and echiuran, among which arthropods were the most abundant. The abundance of taxa and density of benthic organisms had a little difference among the stations within the dumping area, but were significantly lower than those of the stations outside the dumping area. In addition, non-metric multidimensional scaling analysis confirmed that the observed patterns separated the stations within the dumping area from stations outside the dumping area. The evaluation results of the HMs revealed that the dumping area with a large dumping amount was more severely polluted. Dumping dredged materials seemed to have a negative impact on the benthic community in the dumping area. [ABSTRACT FROM AUTHOR]

Surface sediments collected from twelve stations in the Boka Kotorska Bay were analyzed for the level and distribution of twenty-six elements and ten oxides, grain sizes, organic matter, and carbonate content. Potentially toxic elements (Al, Fe, Mn, Cr, Zn, Ni, Cu, Pb, As, Co, U) were determined to assess the contamination status and potential environmental risk according to the single-element indices (enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF)), and combined index (pollution load index (PLI)). The single-element indices EF and CF revealed that the surface marine sediment was moderately polluted with Pb, Cu, and Cr, while Igeo indicated moderate pollution with Ni > Cr > Zn > Cu > As and moderate to heavy pollution with Pb, as a result of the anthropogenic factors. The method of the combined effect of toxic elements, PLI, showed the highest pollution rate at the shipyard location in the Bay of Tivat. Pearson's correlation coefficient (r), principal component analysis (PCA), and cluster analysis (CA) were applied to highlight similarities and differences in the distribution of the investigated elements in the Bay, confirming the claim obtained by the pollution indices. The sediment contamination with most heavy metals, such as Cr, Zn, Ni, Cu, Pb, and As, has been identified in the Tivat Bay area. [ABSTRACT FROM AUTHOR]

Background: With the continuous advancement of global urbanisation, humans have begun to overutilise or improperly utilise the natural resources of bay areas, which has led to a series of ecological and environmental problems. To evaluate the spatial distributions and potential ecological risks of heavy metals in sediments of Shenzhen Bay, China, an analysis of As, Cd, Cr, Cu, Pb, and Zn regarding their content, correlation (Pearson coefficient), pollution degree, and potential ecological risks was conducted. Results: The heavy metal contents in the sediments decreased in the order of Zn > Cu > Cr > Pb > As > Cd, with contents of 175.79 mg kg−1, 50.75 mg kg−1, 40.62 mg kg−1, 37.10 mg kg−1, 18.27 mg kg−1, and 0.20 mg kg−1, respectively. The results showed that the overall sediment quality in Shenzhen Bay generally met the China Marine Sediment Quality criteria, and the heavy metal contents were significantly lower than those reported in the same type of bay area worldwide. Furthermore, the order of grade of potential ecological risk of the heavy metals was as follows: As and Cd were found to pose moderate ecological risks, with their potential hazard indices reaching a high level, whereas the potential ecological hazard indices of Cu, Pb, Zn, and Cr were all at relatively low levels. Conclusions: The potential hazard indices of the heavy metals decreased from the inner bay toward the outside. The accumulation and content of the analysed heavy metals in the Shenzhen Bay sediments are mainly controlled by historical land-source pollution and land reclamation projects. This study presents the current state of sediment quality in Shenzhen Bay. The results may assist in the definition of future bay area management measures specifically targeted at monitoring heavy metal contamination. [ABSTRACT FROM AUTHOR]

The concentrations of major (Al, Fe, Mg, Mn, Na, K and Ca) and trace (Cr, Cu, Ni, Pb and Zn) elements have been determined in inter tidal and beach surface sediments samples collected from North east coast of Tamilnadu, India. Major element analysis showed that the sediments had low concentrations when compared with crustal average and upper continental crust. Using sediment quality guidelines and different types of indexes, current trace elements pollution status in the study area were assessed. Sediment quality guidelines suggest that nickel and lead must be considered as a chemically potential concern in the study area. The indexes used in this study were enrichment factor, geo-accumulation index and modified degree of contamination. Different indexes gave diverse status of inter tidal and beach sediment quality. The results are discussed in the context of the sources and pathways of trace elements in the North east coast of Tamilnadu, India. [ABSTRACT FROM AUTHOR]

Fuzzy comprehensive assessment was applied, for the first time, to investigate the sediment environmental quality and compare the historical variations of heavy metal pollution in Daya Bay and Jiaozhou Bay, which are representative for sub-tropical and temperate zone of China, respectively. Results shown the Daya Bay had undergone three contrasting stages in the past 100 years. Before 1980s, the sediment was not contaminated by metals and its quality generally conformed to class I of China National Standard for marine sediment quality. During from 1980s to 2000s, however, Daya Bay's environment had experienced significant deterioration. The metal concentrations were significantly higher than the background values, suggesting that there was a sharp increase of metal input. The category of sediment quality fell to class II and class III. Copper was the dominant pollutant during that time. The good thing is sediment quality of Daya Bay has improved to class I since 2000s, and chromium turned to be the major pollutant. As for the Jiaozhou Bay, enrichment of heavy metal was generally not detected and the sediment quality strictly conformed to class I during the recent 90 years. Chromium and zinc were the major pollutants in this bay. [ABSTRACT FROM AUTHOR]

Purpose: Multidisciplinary research was carried out to verify the best approach for a reliable assessment of sediment quality in marine areas affected by strong metal enrichment. The study was carried out on Sulcis-Iglesiente marine coastal areas (Sardinia, Italy), where a long-lasting past mining operation strongly contaminated marine sediments with heavy metals (Cd, Pb and Zn). Materials and methods: Surface sediments were analysed for grain size and mineralogical content, total organic carbon, total metal concentrations and sequential extractions. Additionally, ecotoxicological bioassays were performed using Vibrio fischeri (Microtox®) on the solid phase and elutriate, Dunaliella tertiolecta on elutriate and Brachionus plicatilis on elutriate. Results and discussion: Analysed sediments were nearly exclusively sand (98.5–100%) with a very low TOC content; their texture and mineralogy indicated a N-S drift affecting the dispersion of mining contributions. The total concentrations of Cd, Pb and Zn, which are positively correlated, exceeded background and Environmental Quality Standards (EQS) values by up to two orders of magnitude, while sequential extractions revealed their high mobility because Cd and Pb were mainly extracted in the first phase (up to 77 and 82%, respectively) and Zn in the second phase (up to 99%). In spite of this, bioassays recorded the absence of toxicity in all the samples. Conclusions: These apparently conflicting results suggest that ecotoxicological tests cannot replace chemical analyses in sediment quality assessments because they could fail to provide reliable information on the bioavailability of contaminants over time. [ABSTRACT FROM AUTHOR]

Sedimentary dissolved organic matter (DOM) is an important pool of intermediates produced and consumed during early diagenesis of organic matter in the anoxic subseafloor. Rapid degradation of organic matter in the coastal sediment results in stratification of redox zones. However, to date little is known about the selectivity with respect to organic matter of the initial microbially mediated anaerobic degradation processes under contrasting redox conditions and how these affect the composition of DOM. In order to study the effect of sulfate reducing vs. methanogenic conditions on DOM quality and degradation, sediments (0–18 cm) from the Rhône River Delta were incubated, with redox conditions being controlled by sulfate amendment. The progress of incubation was monitored by H 2 , CH 4 , sulfate, DIC, DOC and acetate production. DOM composition was determined by 3D Fluorescence Spectroscopy, i.e., Excitation Emission Matrix Spectroscopy (EEMs), and ultra-high-resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS). Parallel factor analysis (PARAFAC) of EEMs was used to distinguish different groups of DOM (humic-like and protein-like compounds) to evaluate composition, conjugation and size of DOM. Prior to incubation, humic-like sedimentary DOM predominated; nearly half of the molecular formulae (>5000) identified by FT-ICR-MS were CHO and one third were CHNO compounds. During incubation, protein-like DOM and CHNO formulae with 3 and 4 N atoms formulae were rare under both sulfate reducing and methanogenic conditions. Incubation under sulfate reducing conditions resulted in rapid release and net accumulation of dissolved organic carbon (DOC). Protein-like DOM was rapidly cycled and humic-like DOM accumulated. Consistently, CHNO formulae with 3 and 4 N atoms decreased faster, whereas formulae with one N and oxygen-rich unsaturated compounds became more concentrated. In contrast, during incubation under methanogenic conditions, there was no net accumulation of DOC; blue-shift of humic-like peaks suggest the transformation possibly associated with loss of oxygen-bearing functional groups in conjugated structures of humic substances. This interpretation is consistent with the relative decrease of oxygenation and carbon number in the pool of aromatic and highly unsaturated compounds observed by FT-ICR-MS analysis. Approximately 90% of molecular formulae that were lost under methanogenic conditions were accumulated under sulfate reducing conditions. Our results suggest that under sulfate reducing conditions degradation of organic matter results in the accumulation of highly oxidized DOM, while protein-like compounds are selectively consumed. When the redox regime changes to methanogenic conditions, microbes apparently utilize the humic-like and oxygen-rich compounds of the oxidized DOM pool that accumulated under sulfate reducing conditions. Consequently, redox regimes and the associated biogeochemical processes influence rate and fractions of DOM released by and consumed in the deep biosphere, which could ultimately shape the composition of the preserved sedimentary organic matter and the DOM released to the ocean. [ABSTRACT FROM AUTHOR]

Abu Dhabi, the capital of the United Arab Emirates, has a coastline that occupies 76% of the country's Arabian Gulf coastline. The pressures accompanying the economic development that the country is undergoing ultimately affected the marine ecosystem including water and sediment quality. In order to protect the marine ecosystem and public health, the Environment Agency- Abu Dhabi developed ambient marine water and sediment quality standards using the long-term data collected along the coast of Abu Dhabi. Along with the data collected on 39 marine water quality and sediment parameters (hydrography, nutrients, and heavy metals), a review of best practices from jurisdictions whose approach was scientifically based and whose physical conditions were as similar as possible to those found in Abu Dhabi were used for the establishment of marine water and sediment quality limits. These promulgated ambient limits were then used to develop the marine water and sediment regulation that establish two uses of marine waters (protected and general) and an anti-degradation policy. In addition, the ambient water and sediment limits provide a bench mark to both assess trends that may indicate stress to marine flora and fauna and support the work of environmental permitting and enforcement. [ABSTRACT FROM AUTHOR]

The environmental quality of a Ramsar wetland site located at the Cananéia-Iguape-Peruíbe Protected Area (CIP-PA), in São Paulo, Brazil, was assessed by geochemical analyses and biomarker assessments (GPx, GST, GSH, GST, MT, LPO, DNA damage) performed in swimming crab Callinectes danae Smith, 1869 organs (posterior and anterior gills and hepatopancreas) to estimate sediment contaminant bioavailability. The results indicated that two sampling stations, PT and PM, exhibited the worst environmental conditions, as sediments collected at both points contained metal contamination, while crabs exhibited significant responses for GPx, GST, and LPO (mostly during winter). Sediment contamination tended to be associated to fine sediments (both seasons) and organic matter (winter). During the summer survey, Pb concentrations in sediments of station PT exceeded the Brazilian Sediment Quality Guidelines (SQGs) and the Canadian Interim Marine Sediment Quality Guidelines. Metal concentrations in sediments sampled in winter were higher compared with summer, with Co, Ni, and Pb exceeding SQGs levels at PT, whereas Co, Ni, Hg, Zn, and Pb exceeded SQGs at PM. Biomarker induction during summer appeared to be caused by natural variables (water salinity and temperature, and molting cycle), whereas oxidative stress and tissue damage during winter appeared to be more clearly linked to metal contamination. Anterior gills presented the clearest signs of seasonal variability, being more responsive to sediment contamination. The results suggest that metals originated from the upper Ribeira de Iguape River are transported toward the estuarine system, causing effects on C. danae individuals. Additionally, seasonality is a strong factor concerning CIP-PA toxicity, since the rainfall regime significantly modifies the freshwater flow and, consequently, estuarine water salinity, suspended particle and metal inputs, as well as the location of depositional areas. Thus, efforts to mitigate CIP-PA contamination should be based on the control of upstream pollution sources. [ABSTRACT FROM AUTHOR]

Purpose: Contaminated marine sediment can be treated to satisfy the concentration-based chemical criteria, but the treated sediment could still not be appropriate for reuse. This study used ecotoxicity tests to determine the reusability of treated marine sediment on terrestrial land. Materials and methods: Changes in the toxicity of sediment contaminated with a mixture of total petroleum hydrocarbons (TPH) and heavy metals after treatment were investigated using both terrestrial (earthworm and wheat) and aquatic organisms (Daphnia magna, Allivibrio fischeri). Results and discussion: The contaminant concentrations were reduced to meet the remedial goal of this study. As a result, the toxic effects on the tested organisms were reduced. The toxic effects of the reference sediment sample (RSS) that represents the background sediment toxicity were greater on wheat and earthworms than the treated sediment samples (TSSs). This was attributed to factors such as salinity and sediment texture. By comparing the toxicities of the sediment samples with that of the RSS, it was found that not only the contaminant concentrations, but also the sediment physicochemical properties such as pH, salinity, particle size distribution, and nutrient contents need to be considered from the step when the treatment processes are selected. Conclusions: In conclusion, different aspects of the treated marine sediment quality, apart from the level of contaminants regulated, could be tested using ecotoxicity tests to determine the reusability of the treated marine sediment on land. [ABSTRACT FROM AUTHOR]

Offshore fish farms have been active inside the Monastir Bay, Hammemet Gulf for over 10 years, but their environmental impact is still unknown. This study focuses on the evaluation of the fish farming activity impact in the Monastir Bay as revealed by geochemical and benthic foraminiferal data. Samples were collected around three fish cages at different water depths. Total organic carbon (TOC) and total phosphate (TP) in the sediment show higher values beneath the fish cages and decrease proportionally with distance from the cages. Living foraminiferal assemblages around fish farms are dominated by stress-tolerant species with higher abundances of Ammonia tepida, Rosalina bradyi, Elphidium crispum, and Peneroplis planatus. On the basis of our results, A. tepida and Quinqueloculina seminula are confirmed to be tolerant to elevated nutriment content, while Ammonia parkinsoniana seems to be more sensitive to organic enrichment. We also test the Foram-AMBI that is revealed to be a very promising tool by which evaluating the ecological quality status of marine sediment. The results of the present study confirm the suitability of living benthic foraminifera as bioindicators of organic enrichment induced by aquaculture activities. [ABSTRACT FROM AUTHOR]

A comprehensive study was carried out to evaluate the occurrence, significance of concentrations and spatial distribution of heavy metals (Cr, Cd, Ni, Cu, Pb, Hg, Zn and As) in sediments along the Valencia coastline (Spain). The sampling campaign covered 476 km of the coastline in a 4-year period. The highest concentrations of metals in the sediments were mainly Cr, Ni, Zn and Cd (up to 28.93 mg Cr kg−1 dw, 15.80 mg Ni kg−1 dw, 57.13 mg Zn kg−1 dw and 0.293 mg Cd kg−1 dw), obtained in the northern areas, some central areas and in an isolated area on the southern coastline. The Sediment Quality Guidelines applied reveal that for all metals studied, none of them reached, or exceed, the "effects of median range" or the "probable effect level". The pollution index reveals that 75% of the stretch coastline has a low priority risk level and the rest "medium-low priority risk level". And, lastly, Potential Ecological Risk Index shows that all but one zone have low ecological risk. [ABSTRACT FROM AUTHOR]

Abstract Spatiotemporal (2001–2017) characterization of sediment metal concentrations were assessed in 31 small craft harbours (SCHs) in Nova Scotia, Canada by analyzing secondary data from government sediment assessment reports. Surficial sediment samples (n = 576) were collected prior to routine maintenance or constriction dredging activities. Sediment metal concentration ranges were 0.5–62 (As), 0.05–3.8 (Cd), 1–305 (Cr), 0.5–220 (Cu), 0.003–1.85 (Hg), 0.73–583 (Pb) and 5–2300 (Zn) mg/kg (dw), respectively. Most sediment metal concentrations (>56% of samples) were below low effect level and >96% were below high effect level sediment quality guidelines, suggesting limited ecological impairment to marine biota. Despite wide temporal coverage (16 years), large variation in sediment concentrations across SCHs were likely due to regular dredging activities preventing long-term accumulation of contaminants. Spatial distribution and enrichment factor results revealed that Canso was most impacted by metals, followed by Clarks Harbour. Graphical abstract Unlabelled Image Highlights • Small craft harbours (SCHs) are crucial to the Canadian fishing industry. • Metal concentrations were assessed in 31 SCHs in Nova Scotia from 2001 to 2017. • Metal concentrations were compared to Canadian and US sediment quality guidelines. • Few SCHs exceeded high effect SQG thresholds indicating limited risk to aquatic biota. [ABSTRACT FROM AUTHOR]

Impacts from oil exploration, development, and production in the Beaufort Sea, Alaska, USA are assessed using concentrations of metals in sediments collected during 2014 to 2015, combined with a large data set for 1985 to 2006. Concentrations of 7 (1980s) or 17 (1999–2015) metals in 423 surface sediments from 134 stations, plus 563 samples from 30 cores were highly variable, primarily as a function of sediment granulometry with naturally greater metals concentrations in fine‐grained, Al‐rich sediment. Metals versus Al correlation plots were used to normalize metals concentrations and identify values significantly above background. Barium, Cr, Cu, Hg, and Pb concentrations were above background, but variable, within 250 m of some offshore sites where drilling occurred between 1981 and 2001; these areas totaled <6 km2 of 11 000 km2 in the total lease area. Random and fixed sampling along the coastal Beaufort Sea from 1985 to 2015 yielded 40 positive anomalies for metals in surface sediments (∼0.8% of 5082 data points). About 85% of the anomalies were from developed areas. Half the anomalies were for the 5 metals found enhanced near drilling sites. No metals concentrations, except As, exceeded accepted sediment quality criteria. Interannual shifts in metals values for surface sediments at inner shelf sites were common and linked to storm‐induced transitions in granulometry; however, metal‐to‐Al ratios were uniform during these shifts. Sediment cores generally recorded centuries of background values, except for As, Fe, and Mn. These 3 metals were naturally enriched in sediments from deeper water (>100 m) via diagenetic remobilization at sediment depths of 5 to 15 cm, upward diffusion, and precipitation in surface oxic layers. Minimal evidence for anthropogenic inputs of metals, except near some exploratory drilling sites, is consistent with extraction of most oil from land or barrier islands in the Alaskan Arctic and restricted offshore activity to date. Integr Environ Assess Manag 2019;15:209–223. © 2018 SETAC Key Points: Concentrations of 17 metals in sediments collected from 1985 to 2015 in coastal Beaufort Sea are highly variable as a function of sediment granulometry with naturally higher concentrations in fine‐grained aluminum‐rich sediment.Meaningful identification of spatial trends and sediment contamination for metals required normalization of total metal concentrations to total aluminum.Limited observations of metal contamination (<1% of 5082 data points) in sediments from the coastal Beaufort Sea are consistent with recovery of essentially all Alaskan Arctic oil from land or barrier islands; offshore activity has been limited to date.Sediment cores recorded centuries of background metal concentrations. [ABSTRACT FROM AUTHOR]

Abstract Cartagena Bay, one of the Caribbean's hot spots of pollution, is an estuarine system connected to the Caribbean Sea by two straits. Large freshwater discharges from the Dique Canal into the south of the bay produce estuarine conditions strongly related to the seasonal variability of runoff from the Magdalena River watershed. The bay's seasonal conditions may be characterized by three seasons: strong winds/low runoff (Jan.–April), weak winds/intermediate runoff (May–Aug.), and weak winds/high runoff (Sept.–Dec.). This coastal zone is known to be impacted by land-based sources of pollution, including continental runoff, industrial effluents and domestic wastewater. However, previous studies have not sufficiently ascertained the spatio-temporal extent of this pollution. This study addresses the following research question: What is the current extent of water and sediment pollution in Cartagena Bay and which factors control its seasonal variability? Monthly seawater samples (Sept.2014–Aug.2015) were taken from surface and bottom depths at 16 stations in and around Cartagena Bay and analyzed for physical, chemical, and biological parameters. Surface sediments were sampled from the bay's bottom every three months and analyzed for various trace metals. Seasonal variability was observed in nearly all of the water quality parameters, with higher concentrations usually coinciding with the high runoff season. Potential pollution impacts are shown by wet-season averages of total suspended solids (45.0 ± 89.5 mg/l), turbidity (26.1 ± 59.7 NTU), biological oxygen demand (1.20 ± 0.91 mg/l), chlorophyll- a (2.47 ± 2.17 μg/l), nitrate (171.1 ± 112.6 μg/l), phosphate (43.1 ± 63.5 μg/l), total phosphorus (85.3 ± 77.2 μg/l), phenol (2.9 ± 17.4 mg/l), faecal coliforms (798 ± 714 MPN/100 ml) and enterococci (32 ± 30 CFU/100 ml) in excess of recommended threshold values for marine conservation and recreational adequacy. The bay's hypoxic conditions are evident with low dissolved oxygen concentrations (<4 mg/l) found at bottom depths during the wet season, moderate concentrations in the windy season, and low concentrations approaching surface waters during the transitional season, showing a seasonality related to the variability of water circulation and vertical stratification. Lower chlorophyll- a levels found in the water column during the wet season suggest that primary productivity in this eutrophic system is not limited by nutrients, which are abundant due to land-based effluents, but rather by water transparency which is significantly reduced during the wet season due to large sediment loads discharged from the Dique Canal. Sediments from the bay's bottom were found to have concentrations of mercury, cadmium, chromium, copper and nickel in excess of the Threshold Effects Levels (TEL) used as an indicator of potential impacts on marine life. Highlights • We present the bay's first monthly monitoring program of water and sediment quality. • Potential pollution impacts are shown as most parameters exceed threshold values. • Seasonal variability shows most parameters have higher concentrations in wet season. • Hypoxia worsens in the transition season when the bay's water circulation is reduced. • Chlorophyll data suggest that primary productivity is limited by water transparency. [ABSTRACT FROM AUTHOR]

Abstract Sundarban along with its networks of rivers, creeks and magnificent mangroves form a unique ecosystem. Acid sulphate soils have developed in this ecosystem under anoxic reducing conditions. In the present study, we have investigated the distribution of acid sulphate soils along with its elemental characterization and possible sources in four reclaimed islands of Indian Sundarban like Maushuni (I1), Canning (I2), Bally (I3) and Kumirmari (I4). Elements show moderate to strong correlation with each other (P < 0.01; P < 0.05). Except Si, Ca and Pb, a higher enrichment factor was observed for K, Cr, Mn, Fe, Ni, Cu and Zn. Geo-accumulation index values of all sampling locations reveal that Cr, Fe, Cu and Zn are in I geo class 1. The pollution load index value of the reclaimed islands of Indian Sundarban varies between 1.31 and 1.48. The observation of this study could help to strategize policies to mitigate and manage acid sulphate soils in Indian Sundarban. Highlights • First ever report of the presence of acid sulphate soil in reclaimed islands of Indian Sundarban. • Accumulation and distribution of major elements and trace metals in acid sulphate soils were studied. • A higher enrichment factor was observed for K, Cr, Mn, Fe, Ni, Cu and Zn. • The enrichment of Al, Si, K, Ca, Ni, Mn, and Pb were found not to be geologic in origin. • The pollution load index value was maximum at Bally Island. [ABSTRACT FROM AUTHOR]

The microbial community assembly processes and underlying mechanisms in response to heavy metal accumulation in coastal sediments remain underexplored. In this study, the heavy metal concentration in samples were found below the marine sediment quality standards. Through partial Mantel tests and linear regression analysis, Cd was identified as the major influencing factor, displaying strongest correlation with the bacterial community in the sediments. The class Desulfuromonadia was identified as a biomarker which showed enrichment in the sediments with high Cd content. Additionally, the results of null model and the neutral community model demonstrated the prominent role of stochastic processes in the assembly of bacterial community. However, with the increase in Cd concentration, the influence of selection processes intensified, resulting in a decline in species migration rate and subsequent reduction in ecological niche width. Furthermore, the intensified competition and an increase in keystone species among bacterial populations further enhanced the stability of the microbial co-occurrence network in response to high Cd concentration. This study offers an insight into the effects of heavy metal on microbial assembly and coexistence, which are conducive to marine ecosystem management and conservation. [Display omitted] • Cd is the major factor with the strongest correlation to bacterial richness/diversity. • Class Desulfuromonadia exhibited enrichment in high-Cd sediment environments. • Stochastic assembly key to maintaining stable bacterial diversity. • The prominent stochastic assembly process decreases with Cd accumulation. • Cd accumulation intensifies competition among bacterial populations. [ABSTRACT FROM AUTHOR]

This work is the first systematic quantitative analysis of the heavy metal situation along the Zhejiang coastal region focusing on the integrative assessment of the concentrations of seven heavy metals (Cu, Cd, Hg, Zn, Pb, Cr, and As) in surface sediments during the 2012–2015 period. Different heavy metal contamination indices were used for surface sediment quality assessment purposes. The numerical results revealed a noticeable spatial fluctuation of the degree of contamination throughout the region during the four years considered. Higher contamination levels and ecological risks were detected in the southern part of the Zhejiang coastal region. It was found that the Cu, Cd and Hg were the predominant contaminants along the Zhejiang coast with mean regional concentrations varying between 29.1 and 34.2, 0.12–0.17, and 0.044–0.052 mg/kg, respectively. The Cr and Pb exhibited lower contamination levels than the other metals during each one of the years 2012–2015. Stochastic site indicators of heavy metal contamination were used to assess regional uncertainties and obtain useful physical interpretations of the state of contamination of the Zhejiang coast. These indicators can be expressed explicitly in terms of probabilities of heavy metal contamination (either at a global scale or spatially distributed over the coastal region), and therefore they can be considered as risk indicators. It was found that the fraction of the coastal region where excess contamination occurred could never exceed the ratio of the mean heavy metal contamination over the selected threshold. In half of the coast study region, the degree of heavy metal contamination was higher than the median spatial contamination values during the month of August of the years 2012–2015. The spatial means of excess contamination and excess differential contamination increased as the relative area of over-contamination increased. Within the substantially contaminated sub-region of the Zhejiang coast, stronger contamination correlations were observed between locations separated by shorter distances. These correlations were higher when smaller thresholds were considered. As regards the spatial connectivity of the corresponding contamination risks, it was found that 44%, 31%, 39% and 63% of the location pairs in the Zhejiang coast simultaneously experienced moderate risks during the years 2012, 2013, 2014 and 2015, respectively. The ratio of the probability of excess contamination at both locations separated by distances < 20 km over the probability of excess contamination at either one of these two locations was high even for large thresholds, indicating that locations with high contamination are concentrated rather than being dispersed along the Zhejiang coast. Lastly, another interesting finding is that the characterization of the Zhejiang coastal region as over-contaminated is very sensitive to the DC threshold considered, that is, a small increase in the threshold selected can reduce significantly the probability that region is characterized as over-contaminated. [ABSTRACT FROM AUTHOR]

This study aimed to determine sediment contamination in the Beidagang Wetland Nature Reserve to describe atmospheric deposition of trace metals. We analyzed Hg, Cd, Pb, TOC, TN, TP, δ13C, and δ15N, and studied their variations in surface sediments and in the vertical profiles of sediment cores collected from the reserve. Evaluation of environmental trace metal contamination using sediment quality guidelines and geochemical background values indicated that the risk of metal pollution in the reserve sediments was relatively low. Concentrations of Hg, Cd, and Pb in the sediments were much lower than concentrations in sediment samples from Bohai Bay and polluted rivers in Tianjin. Enrichment factors indicate that samples are moderately contaminated with Hg, Cd, and Pb; whereas the geo-accumulation index results classify the sediments as uncontaminated to moderately contaminated with Hg, Cd, and Pb. The distribution patterns of trace metal concentrations in the three core samples were uniform. δ13C and δ15N were used to track the sources of TOC and TN in sediments. Results show that TOC mainly originated from the residue and decaying matter of aquatic plants (e.g., algae, reeds, and Typha), while TN was derived from soil N and elevated atmospheric N deposition. Because domestic and industrial waste is not discharged into the Beidagang Wetland Nature Reserve, trace metals found in sediments mainly originate from atmospheric deposition. The results provide baseline data for analysis of trace metal accumulation in Beijing-Tianjin-Hebei, a region subject to atmospheric deposition in northern China. [ABSTRACT FROM AUTHOR]

Abstract The distribution, sources and potential ecological risk of priority polycyclic aromatic hydrocarbons (PAHs) in sediment from the Amazon River Estuary (Macapá and Santana, Amapá, Northern Brazil) were investigated. The total PAHs concentration (∑PAH) ranged from 22.2 to 158.9 ng g−1 dw (mean value 49.4 ng g−1 dw). PAHs levels in the study area were relatively low than those in nearby areas and other coastal zones worldwide, and could be considered as baseline for PAHs in Amazonic sediments. PAHs ratios and the statistical analysis showed that fossil fuel and biomass combustions, primarily from local sources, were the dominant PAHs origins. The potential ecological risk was assessed on the basis of the sediment quality guidelines, and it was found that PAHs in the sediments of the Amazon River Estuary do not cause adverse effects on living organisms; however, the abundance of naphthalene and the presence of dibenzo[ a , h ]anthracene and benzo[ a ]pyrene deserve more attention. Highlights • Sampling sites exhibited low PAH levels. • Naphthalene was the most abundant PAH in the studied area. • PAH were primary from pyrogenic processes related emissions from local sources. • Mobility of PAH seems to be highly influenced by heavy tropical rains. • PAH in the sediments should not cause adverse effect on organisms. [ABSTRACT FROM AUTHOR]

Abstract Sediment geochemical characteristics were analyzed to assess how anthropogenic activities affected the Daya Bay, a subtropics bay adjacent to the most economically developed region of China. Vertical profiles of heavy metal contents and their enrichment factors indicated the development of Daya Bay environment in the past 100 years basically experienced three stages, which were closely consistent with the economic development. Before 1980s, the concentration of heavy metals was basically at the background level. Contamination of metals, particularly for Cr, Ni, Cu, Zn, Cd, and Pb, generally began in mid-1980s and became serious in 2000s. However, after late-2000s, the sediment quality had been radically improved. Heavy metals in nearshore sediment of Daya Bay were all closely related with import of anthropogenic and/or terrestrial material, whereas those in offshore were likely to be related with joint influence from the anthropogenic activities and the natural processes. Highlights • The evolution of Daya Bay environment in the past 100 years basically experienced three stages. • Before 1980s there was no record of heavy metals pollution. • Contamination of metals generally began in mid-1980s and became very serious in 2000s. • After late-2000s the sediment quality had been radically improved. • Contributions of anthropogenic and natural metals in sediment varied with heavy metal types and regional position. [ABSTRACT FROM AUTHOR]

Abstract Five stations (≤250 m from the well heads) from three exploration wells of different ages from the SW Barents Sea were studied to investigate the spreading of drill cuttings and sediment quality. Two of the wells were drilled before the restriction of use of oil-based drilling fluids (1993). Elevated concentrations of Ba were found in sediments near all the wells with the highest concentrations at ≤60 m from the well head. The thickness of drill cutting layers was between >20 cm (well head) and 2 cm (250 m from the well head). The sediment quality varied from very bad (oldest well) to background (normal) (newer wells). Regulations led to better sediment quality. Metal concentrations from the oldest well suggested that the top 4 cm of the core represents sediment recovery. However, Ba concentrations of the top sediment layer at all the stations of the three wells indicate no physical recovery. Highlights • Drill cuttings were studied in sediments <250 m away from different age wells. • Elevated concentrations of Ba are found in all of the wells ≤60 m from the wellhead. • The drill cutting layers are from >20 cm (wellhead) to 2 cm (250 m from wellhead) thick. • The sediment quality varies from very bad (oldest well) to background (newer wells). • Regulations in 1993 and after led to improving effect on the sediments quality. [ABSTRACT FROM AUTHOR]

Gondwana deposits are extensively found across the continents. Here we study the Middle Permian Barakar Formation from the marginal Gondwana Basin, eastern India, being deposited in a normal fault setting. Availability of extensive cores as well as geophysical log suites (gamma-resistivity-density from drilled wells) from the study area helped us achieving high resolution interpretation. Core study identifies fluvial sedimentary architectures, which were correlated with the geophysical logs and modeled field-wide to understand vertical and horizontal facies disposition. The facies analysis has been used to establish a sequence stratigraphic model of the cyclic Barakar deposition. Four major fining upward depositional sequences were identified, each sequence comprises of low accommodation system tract (LAST) at base and high accommodation system tract (HAST) at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterizes HAST, reflecting a gradual shift from braided to meandering depositional system from bottom to top of each cycle. Study reveals depocenter to be in the western part, supported by eastward thinning of sediment packets, all being deposited in a half-graben setting. [ABSTRACT FROM AUTHOR]

This review of 19 chemical approaches used in assessing sediment quality are classified into empirical, mechanistic and sediment quality indices (SQI) groups. Empirical sediment quality guidelines (SQGs), based on matching chemical and biological-effects data and the mechanistic techniques, founded on equilibrium partitioning principals (EqP), are well established and most used. Empirical SQGs provide a useful screening tool to initially identify locations and chemicals of most concern, but are not regulatory criteria. The EqP approach is causally linked however, the scheme assumes porewater chemistry largely controls sediment toxicity. SQIs are not based on matching chemical-biological data and combine schemes with multiple narrative intents. The 41 SQGs reviewed show a considerable range in upper and lower guideline values. Grain size and organic content should be included into SQGs, however inclusion of suspended sediment into SQGs raises concerns. SQGs are built into decision-tree schemes with other lines-of-evidence and evaluated in a weight-of-evidence framework. [ABSTRACT FROM AUTHOR]

Thirty bottom sediment samples were collected from northern Hurghada coast, Red Sea, Egypt to evaluate the level of anthropogenic pollutants, using enrichment factor (EF), potential ecological risk index (PERI), soil pollution index (SPI), potential contamination index (Cp) and multivariate statistical analysis (correlation analysis, principal component analysis, and hierarchical cluster analysis). Fe, Mn, Zn, Pb, Ni, Cu, Co and Cd were analyzed by Atomic Absorption Spectrophotometer. Results indicated that the average values of Pb and Cd were greater than the ones recorded from many other worldwide coastal areas. The studied sediments are extremely severe enrichment with Pb and Cd (EF > 50), severe enrichment with Zn (EF = 10–25), very high risk with Cd (PERI ≥ 320), high risk with Pb (160 ≤ PERI ˂ 320), highly contaminated with Pb (SPI > 3), a severe contamination with Pb (Cp > 3). The accumulation of pollutants is associated with the muddy and fine sediment; especially the studied area is a semi-closed bay, characterized by long time of water retention. Possible sources of metals pollution in the studied area are shipment operations and anticorrosive and antifouling paints, dredging and land filling, municipal wastewater from tourist centers and fishermen cargo boats. [ABSTRACT FROM AUTHOR]

Abstract: Controls governing the speciation and accumulation of Se in a 3.7‐ha marsh influenced by mine drainage were assessed through examination of water balance, water quality, sediment, and plant tissue components. Over the 8‐mo study period (April through November, 2009), mean monthly flows ranged from 1600 to 2300 m3 d−1 (hydraulic retention time of 1–3 d). Total Se concentrations in the marsh outflow were lower than the inflow by 0.4 to 6.2 μg L−1 (mean difference = 3.3 μg L−1), illustrating Se removal. The Se accumulation pathways are illustrated by elevated concentrations of Se in sediments (3–35 mg kg−1 dry wt) as well as in below‐ground (2–41 mg kg−1 dry wt; mean = 10 mg kg−1 dry wt) and above‐ground (0.8–6.3 mg kg−1 dry wt; mean = 2 mg kg−1 dry wt) emergent plant tissues. Redox stratification in the shallow water column had a marked effect on Se speciation and behavior, illustrating bottom water removal of dissolved selenate in suboxic horizons and increased mobility of dissolved organo‐Se. Mass balance data yielded inflow and outflow loading rates for Se of 27 and 23 g d−1, respectively (net accumulation rate of 4 g d−1 or 0.11 mg m2 d−1). The rate of accumulation as calculated from the mass balance agrees with independently measured rates of Se accumulation in sediments for the site (3.6–8.1 g d−1 or 0.10–0.22 mg m−2 d−1). Environ Toxicol Chem 2018;37:1824–1838. © 2018 SETAC [ABSTRACT FROM AUTHOR]

Complexity of anthropogenic influences on coastal ecosystems necessitates use of an integrated assessment strategy for effective interpretation and subsequent management. In this study a multiple lines of evidence (LOE) approach for sediment assessment, that combined use of chemistry, toxicity, and benthic community structure in the sediment quality triad was used to assess spatiotemporal changes and potential risks of persistent toxic substances (PTSs) in sediments of Masan Bay highlighting “long-term changes” between 1998 and 2014. Specific target objectives encompassed sedimentary PTSs (PAHs, alkylphenols (APs), and styrene oligomers), potential aryl hydrocarbon receptor (AhR; H4IIE- luc assay)- and estrogen receptor (ER; MVLN assay)-mediated activities, and finally several ecological quality (EcoQ) indices of benthic community structure. Concentrations of target PTSs in Masan Bay sediments were generally less by half in 2014 compared to those measured in 1998. Second, AhR-mediated potencies in sediments also decreased during this time interval, whereas ER-mediated potencies increased (+3790%), indicating that there has been substantial ongoing, input of ER agonists over the past 16 years. Potency balance analysis revealed that only 3% and 22% of the AhR- and ER-mediated potencies could be explained by identified known chemicals, such as PAHs and APs, respectively. This result indicated that non-targeted AhR and ER agonists had a considerable presence in the sediments over time. Third, EcoQ indices tended to reflect PTSs contamination in the region. Finally, ratio-to-mean values obtained from the aforementioned three LOEs indicated that quality of sediments from the outer region of the bay had recovery more during the period of 16-years than did the inner region. Overall, the results showed that even with the progress supported by recent efforts from the Korean governmental pollution control, PTSs remain a threat to local ecosystem, especially in the inner region of Masan Bay. [ABSTRACT FROM AUTHOR]

The red king crab invaded Norwegian coastal waters in the early 1990s after having been introduced from the northern Pacific to the Russian Barents Sea coast. The crab stock increased rapidly in NE northern Norway in the latter half of the 1990s, and since 2002 there has been a commercial fishery in the eastern invaded areas. The crab is an active predator on benthic fauna especially feeding in deep soft-bottom environments. The present study is a follow-up of previous studies (2007–09) to assess the effects of the king crab predation on soft bottom species composition, ecological functioning and sediment quality. Macroinfauna (> 1 mm) was investigated in three fjord areas in the Varanger region with low, moderate and very high crab abundances, respectively. Compared with data from 1994, most benthic species were markedly reduced in abundance, in particular non-moving burrowing and tube-dwelling polychaetes, bivalves and echinoderms. However, a few species appeared to recover from 2007–09 to 2012. Changes in ecological functioning were assessed using ‘biological traits analysis (BTA)’. Following the crab invasion there was a relative reduction of suspension and surface deposit feeding species, an increase in mobile and predatory organisms and an increase in those with planktotrophic larval development. From low to high crab abundances functioning changed from tube-building, deep deposit feeding and fairly large size to free-living, shallow burrowing and rather small size. With regard to sediment reworking, downward and upward conveyors were reduced whereas surficial modifiers increased. The changes imply that sediment biomixing and bioirrigation were reduced leading to a degraded sedimentary environment. It is suggested that establishing relationships between ecosystem functioning and crab abundances may form the basis for estimating ecological costs of the crab invasion. Such knowledge is important for managing the crab in the Barents Sea area being both a non-indigenous species affecting native ecosystems as well as a valuable resource for commercial fishery. [ABSTRACT FROM AUTHOR]

The aim of this study is an assessment of metal pollution levels in Aegean Sea sediment. Sediment samples collected from 7 different locations (Yeniköy, Edremit, Ayvalık, Dikili, Aliağa, Hekimadası, and Ildır) along the northern Mediterranean region of Turkey were investigated for 11 elements (Cu, Fe, Zn, V, Cd, Ni, As, Pb, Mn, Co, and Cr). Graphite furnace atomic absorption spectrophotometry (GFAAS) and flame atomic absorption spectrophotometry (FAAS) were used for elemental analysis. The findings were evaluated with sediment assessment methods by taking two different values as a reference and then investigating the adverse biological effects of elemental profiles on living organisms. Pb, Mn, As, Cd, and Cr concentrations were within a moderate to significant range in terms of contamination factor (Cfi), albeit varying according to reference and location. The most problematic region and elements regarding the enrichment factor (EF) was Ayvalık and As, Ni, Cu, Pb, Co, and Cd. However, according to the EF, the anthropogenic effect was not at an alarming level. This was further supported by the results of the geoaccumulation index (Igeo). The findings of the modified degree of contamination (mCd) and the pollution load index (PLI) suggested that the accumulation was greatest in Ayvalık, and the least in Hekimadası and Ildır. The location with the highest elemental total toxic unit (ΣTU) was Edremit. The effect of the existing element profile on organisms was 21% in this location when the mean effect range-median quotient (m-ERM-q) was considered. As and Ni concentrations in all stations were found to be higher than threshold effect level (TEL) and Effect Range Low (ERL). Ni levels in Edremit exceeded the probable effect level (PEL) and Effect Range Median (ERM). Toxic unit (TU) values of these two elements in all stations ranged from 59.30 to 80.43%. [ABSTRACT FROM AUTHOR]

Jeong, H.; Ra, K.; Kim, K.-T.; Kim, E.-S.; Lee, S.-Y., and Choi, M.-S. 2018. Tracing the pollution source using Pb isotopes in sediments of the coastal region surrounding the national industrial complex, Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1456–1460. Coconut Creek (Florida), ISSN 0749-0208. 166 sediment samples from Ulsan Bay and Shihwa Lake that is special management sea area were collected in 2014 not only to study the spatial distribution and pollution assessment of Pb but also to identify anthropogenic pollutions for Pb isotopes. The mean Pb concentrations of road-deposited sediments were higher than those of stream and coastal sediments in the study area. In all sediment samples, Ulsan showed an average concentration of 2 to 4 times higher than that of Shihwa. Pb concentrations in coastal sediments of more than 50 % were below the threshold effect level (TEL) of Korean marine sediment quality guidelines. The high exceedance of probable effect levels (PEL) showed in large harbors and near industrial facilities. Road-deposited sediments in Ulsan and Shihwa exceeded the class 2 (potentially toxic to benthic organisms) of Korean freshwater sediment quality guidelines. For both study areas, Pb isotope ratios tend to decrease with increasing Pb concentrations in sediments. In the case of Ulsan, high concentrations and low 206Pb/207Pb isotopic ratios were observed nearby the smelter and lead ore import harbor, indicating that Pb was released into the road surface during transportation using the vehicle and then moved to the marine area through the stream. However, Shihwa has a lot of small facilities (>19,000), it is difficult to clearly identify Pb pollution sources. [ABSTRACT FROM AUTHOR]

Surface sediment samples were collected from the Pacific sector of the Arctic Ocean during the 6thChinese National Arctic Research Expedition (CHINARE), 2014. Concentrations and extractabilities of six toxic metals (Cd, Cr, Cu, Ni, Pb, and Zn) were determined using a modified sequential extraction procedure as described by the European Community Bureau of Reference (BCR). A new analytical hierarchy approach to risk assessment, involving sediment quality guidelines and risk-assessment codes, is described for metals in marine sediments from the Arctic Ocean. Results indicate a mobility order of Pb > Cd > Cu > Zn > Ni > Cr with mean liable fraction (F1+F2+F3) being 83.0%, 81.6%, 62.0%, 47.1%, 42.1%, and 15.6%, respectively. Ni presents the most serious ecological risk in the study area, with most samples (93.9%) indicating medium risk, followed by Cu (54.5%) and Zn (27.3%). For Ni and Zn, there are also samples showing high ecological risk (Ni at site NB02, northern Bering Sea; Zn at R07, northern Chukchi Sea). The ecological risk for Cr indicates low ecological risk (93.9%) and some medium risk (6.1%). All Cd assessments indicate low ecological risk, while most Pb assessments indicate zero (33.3%) to low risk. The new ecological risk assessment method improves on assessments based on metal mobility or concentration alone. [ABSTRACT FROM AUTHOR]

The copepod Acartia tonsa was used as a model species to assess marine sediment quality. Acute and chronic bioassays, such as larval development ratio (LDR) and different end-points were evaluated. As a pelagic species, A. tonsa is mainly exposed to water-soluble toxicants and bioassays are commonly performed in seawater. However, an interaction among A. tonsa eggs and the first larval stages with marine sediments might occur in shallow water environments. Here we tested two different LDR protocols by incubating A. tonsa eggs in elutriates and sediments coming from two areas located in Tuscany Region (Central Italy): Livorno harbour and Viareggio coast. The end-points analyzed were larval mortality (LM) and development inhibition (DI) expressed as the percentage of copepods that completed the metamorphosis from nauplius to copepodite. Aims of this study were: i) to verify the suitability of A. tonsa copepod for the bioassay with sediment and ii) to compare the sensitivity of A. tonsa exposed to different matrices, such as water and sediment. A preliminary acute test was also performed. Acute tests showed the highest toxicity of Livorno's samples (two out of three) compared to Viareggio samples, for which no effect was observed. On the contrary, LDR tests with sediments and elutriates revealed some toxic effects also for Viareggio's samples. Results were discussed with regards to the chemical characterization of the samples. Our results indicated that different end-points were affected in A. tonsa , depending on the matrices to which the copepods were exposed and on the test used. Bioassays with elutriates and sediments are suggested and LDR test could help decision-makers to identify a more appropriate management of dredging materials. [ABSTRACT FROM AUTHOR]

In this study, analysis results reveal two main deposition zones are located at the flank of upper Gaoping Submarine Canyon and Lower Fangliao Basin offshore SW Taiwan. The non-event related sediments deposited in past 150 years (i.e., 632 Mt km-2) was delivered and transported from Gaoping River by suspension process with tides and coastal currents and gradually spread out offshore. M eanwhile, the total mass of accumulation sediments is 1922 Mt km-2, accounting for 40% Gaoping River's sediment load and suggesting that the deposition process is mainly controlled by natural hazards. Sedimentation rates in much of the study area, except in the main deposition zones, are less than 0.5 cm yr-1 (5 m kyr-1). Compared with the studies at the instability seafloor caused by high sedimentation rates (~30 m kyr-1), the offshore southwestern Taiwan is relatively stable. In this study, we also discovered a series of sediment waves located on the upper continental slope between Gaoping and Fangliao Submarine Canyons, which is related to the creeping process on seafloor. In summary, our results reveal the fluid activities, existence of weak layers and earthquake triggering are potential factors which might induced seafloor failures offshore southwestern Taiwan. [ABSTRACT FROM AUTHOR]

Sediment quality guidelines vary wildly across nations. The approaches to derive these guidelines range from crude percentile rankings of total concentrations of single chemicals to theoretical approaches that are driven by biological available effect levels. This results in a range of orders of magnitude for “safe” or threshold levels by chemical. Even the more scientifically advanced approaches using theoretical approaches are problematic in that they do not consider chemical mixtures, alternate routes of exposure, and other ligands that limit bioavailability. In the end, all that matters is that desirable resident biota are protected and with no significant ecological impacts. Complicating this determination is the role of habitat, flow, sedimentation, and nutrients—all of which are common in human-dominated waterways. A possible effective way forward is to consider the common, relevant stressors that may influence biotic communities associated with sediments. This approach would consider relevant sensitive species in terms of their ecological context and dominant exposure pathway (considering habitat, overlying water, sediment, periphyton, and hyporheos). In addition, the sum of water column (and pore water) and sediment probable effect concentration vs probable no effect concentrations ratios would be summed and considered for mixtures. Since this non-scientific mixture effect assessment may be overly conservative, in situ caged toxicity tests with benthic and water column organisms exposed to sediments, pore waters, and overlying water would be conducted for field validations along with comparisons of indigenous biota to BioCriteria. [ABSTRACT FROM AUTHOR]