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In this study, the sources of nine heavy metals (Cd, As, Hg, Cu, Pb, Ni, Cr, Zn, and Co) in the sediments of the Bohai Sea were quantitatively identified through a positive factor matrix to provide better advice for marine and coastal management. In Bohai Sea sediments, most metals fell below detectable contamination levels, including As, Cu, Pb, Ni, Cr, Zn, and Co. Unfortunately, Bohai Sea sediments were moderately to significantly enrich with Cd and Hg, posing potentially adverse ecological risks to aquatic ecosystems. Our modeled results showed three factors representing natural, anthropogenic, and atmospheric deposition sources. Enriched Cd and Hg were likely derived from anthropogenic activities through river runoff and atmospheric deposition due to adjacent Zn smelting and chlor-alkali production, respectively. The other metals were mainly derived from natural sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Background metal concentrations are important in assessing pollution level of marine sediments; however, they can be significantly altered by local depositional environments, resulting in significant errors in regional pollution assessment. This study was based on the investigation of the background levels of heavy metals in the Bohai Sea sediments using sediment core, 2-sigma outlier, and regression methods. We also estimate the ecological risks of heavy metals for surface sediments collected from the Bohai Sea using the three methods mentioned above. Ecological risks of heavy metals calculated using the regression method show wide disparities and significant differences from those calculated using the sediment core and 2-sigma methods, indicating that the regression method is not suitable for the Bohai Sea, likely as a result of its complex sources. Conversely, the estimated ecological risks using the sediment core method are moderate, and most heavy metals, except for Hg and Cd, have negligible contamination., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

The heavy metal contents (Cr, Cu, Zn, Cd, Pb, Hg, and As) of 88 surface sediment samples from the western Sunda Shelf were analyzed to determine their spatial distribution patterns and contamination status. The results demonstrated that high enrichment regions of heavy metals were focused in the Kelantan, Pahang, and Ambat river estuaries, and deep water regions of the study area. These high enrichment regions were mainly controlled by riverine inputs and their hydrodynamic conditions. The enrichment factor (EF), geoaccumulation index (I geo ), and potential ecological risk index (PERI) were used to assess heavy metal accumulation. The results indicated that the study area was not significantly contaminated overall at the time of the study; however, Cd, As, and Hg were at levels corresponding to moderate contamination at many stations located in the Pahang River estuary, Kelantan River estuary, and north-eastern region of the study area, primarily because of anthropogenic activities., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, we analyzed heavy metals in 404 surface sediment samples from the Bohai Sea to measure contamination status and distribution. We found Zn levels to be the highest, whereas Hg concentrations were the lowest of measured heavy metals. We found that the samples containing the most heavy metals were those collected from Fuzhou Bay, Jinzhou Bay, central Bohai Sea mud area, and the Yellow River Delta. Further analyses suggest that these heavy metals in surface sediments in the Jinzhou Bay and Fuzhou Bay pose a serious ecological risk, with substantial Cd and Hg accumulation in the Jinzhou Bay and Yellow River Delta regions being indicative of intense human activities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

The present study aims to examine the distribution, sources and potential risks of toxic metals in the northern Bay of Bengal, Bangladesh. We found Cu, Pb, Zn and Hg exhibited similar spatial distribution pattern. Influenced by the Ganges-Brahmaputra River and the Karnafuli River, there were higher concentrations of these metals associated with the finer sediment and higher TOC in the northeastern portion of the study area. Moreover, coal transportation was assumed to account for the distinctive spatial distribution of As with higher concentration down the Port of Chittagong in the eastern boundary. Chemical-screening level assessment demonstrated the majority of the metals exceeded the threshold effect values, indicating certain possibility of adverse effect. The concentrations of Ni were higher than the possible hazardous values, suggesting high possibility of harmful consequences. The uncontaminated sediments mainly distributed in northwestern and the central portions affected by the delta erosion and marine transported sediments., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Magnetic iron-titanium binary oxide as an effective adsorbent for arsenic contaminant is a challenge primarily because of their bulk structure and agglomeration effect. Herein, a novel and uniform sandwich-like magnetic Fe 3 O 4 @TiO 2 sheets were synthesized by utilizing a facile strategy involving amorphous-to-crystalline transformation and reduction in H 2 , to achieve dispersed anatase TiO 2 nanoparticles with a small size of ∼8 nm anchored on Fe 3 O 4 sheets. The resultant Fe 3 O 4 @TiO 2 sheets nanocomposite possessing a high specific surface area of ∼89.4 m 2  g -1 and available magnetic susceptibility of ∼20.0 emu g -1 , significantly enhanced the photocatalytic oxidation property of arsenite and considerable adsorption capability for arsenic removal. The adsorption capacities of As(V) and As(III) with UV-assisted from adsorption experimental results were 36.36 and 30.96 mg g -1 , respectively, while the residual concentrations for both As(V) and As(III) were lower than the strict limit of 10 μg L -1 . Adsorption equilibriums were almost reached within 45 min. In addition, the adsorbent exhibited excellent stability over a broad pH range of 3-9 and still maintained great removal efficiency after five time regeneration cycles. Furthermore, except for silicate and phosphate, the extremely weak inhibiting influences of common co-existing ions in arsenic removal process, demonstrated that the developed magnetic Fe 3 O 4 @TiO 2 sheets with unique nanostructure could be a promising efficient adsorbent for arsenic removal., (Copyright © 2019 Elsevier Ltd. All rights reserved.)