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Background: Heavy metals and total petroleum hydrocarbons (TPHs) are important pollutants in the aquatic ecosystem, and their long-term resistance, bio-accumulation, and bio-magnification during the food chain may cause adverse ecological and health risks., Methods: In here, the distribution and risk assessment of six heavy metals Cd, Pb, Ni, Cu, Zn, Cr, and TPHs were performed in the sediments of 32 regions situated in two mangroves (Tiab and Azini estuaries, Hara Mangrove forest protected area) and coral habitats (Larak and Hengam Islands) in Northeast of the Persian Gulf during 2020-2021. An atomic absorption device was used to determine the concentrations of heavy metals. Ecological risk of heavy metals is assessed through indices contamination factor (CF), contamination degree (CD), modified contamination degree (MCD), pollution load index (PLI), potential ecological risk index (PERI), and geoaccumulation index (Igeo). The spatial distribution of heavy metals was mapped through the inverse distance weighting (IDW) method in ArcMap., Results: The concentration of heavy metals indicated significant differences in spatial distribution. The maximum concentration of Cd 1.64 ± 0.001, Cr 18.41 ± 0.41 and Cu 40.5 ± 0.28 µg/g was observed at the regions situated in the Hara Mangrove forest protected area. Azini estuary had the maximum value of Zn 94.61 ± 30.74 and TPHs 4.47 ± 1.93 µg/g and finally, the highest value of concentration Ni 135.22 ± 1.85 µg/g and Pb 17.87 ± 2.17 g/gµ was found in Tiab estuary. The studied regions in the Tiab estuary and Hara Mangrove forest protected area were more contaminated than others and had considerable risks of Ni and Cd. Average ecological indices indicated the sediments of these areas especially Tiab, Hara Mangrove forest protected area, and Azini are moderately to considerably contaminated with Cd and Ni. Tiab was identified as the most contaminated area and all stations except Hengam Island were exposed to considerable ecological risks. Cadmium was found to be the riskiest heavy metal in the investigated region. The distribution of TPHs indicated there is no pollution of TPHs in the region. In all studied stations, the PELq (Toxicity of TPHs) and CF values showed the absence of potential risks of TPHs in sediments., Conclusions: The findings indicated considerable contamination of Cd and Ni in the mangrove areas, especially Tiab, and it seems necessary to identify, manage, and control possible sources of 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 © 2024 Elsevier GmbH. All rights reserved.)

The significant increase in the pollution of heavy metals and organic pollutants, their stable nature, and their high toxicity are gradually becoming a global crisis. In a recent study, a comprehensive assessment of the spatial distribution of heavy metals and total petroleum hydrocarbons (TPHs), as well as an assessment of their ecological risks in the sediments of 32 stations located in commercial and industrial areas (Mainly focusing on petrochemical and power industries, desalination plants and transit Ports) of Hormozgan province (East and West of Jask, Bandar Abbas, Qeshm, and Bandar Lengeh) was performed during 2021-2022. The sediment samples were digested with HNO 3 , HCl and HF solvents. The concentration of heavy metals was determined with furnace and flame systems of atomic absorption spectrometer. The concentration of heavy metals showed significant spatial changes between stations. The ecological assessment indices between the regions indicated that the stations located in Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan had a higher intensity of pollution than other places and significant risks of pollution, especially in terms of Cr and Ni. The average contamination degree (CD) (14.89), modified contamination degree (MCD) (2.48), pollution load index (PLI) (2.32), and potential ecological risk index (PERI) (100.30) showed the sediments in the area of Shahid Bahonar Port, Suru beach and Khor gorsouzuan, experience significant to high levels of pollution, especially Cr and Ni. Using contamination factor (CF) and Geoaccumulation index (Igeo), Cr was considered the most dangerous metal in the studied areas. Based on the global classification of marine sediment quality for the concentrations of TPHs, the sediments of the studied stations were classified as non-polluted to low pollution. In all regions, indices of the PELq (General toxicity) and CF (Contamination factor) were much lower than 0.1 and 1 respectively, showing the absence of adverse biological effects caused by TPHs in sediments. It is necessary to consider comprehensive and impressive strategies to control and reduce pollution of heavy metals, especially in the areas of Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan, so that the sources of this pollution are required to be identified and managed., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The challenges of commercial species with the threats of climate change make it necessary to predict the changes in the distributional shifts and habitat preferences of the species under possible future scenarios. We aim to demonstrate how future climatic changes will affect the habitat suitability of three species of commercial fish using the predictive technique MaxEnt. The dataset used to extract geographical records included OBIS (54%), GBIF (1%), and literature (45%). The output of the model indicated accurate projections of MaxEnt (AUC above 0.9). Temperature was the main descriptor responsible for the main effects on the distribution of commercial fish. With increasing RCP from 2.5 to 8.5, the species would prefer saltier, higher temperatures and deeper waters in the future. We observed different percentages of suitable habitats between species during RCPs showing distinct sensitivity of each fish in facing climate changes. Negative effects from climate change on the distribution patterns of commercial fish were predicted to lead to varying degrees of reduction and changes of suitable habitats and movement of species towards higher latitudes. The finding emphasizes to implement adaptive management measures to preserve the stocks of these commercial fish considering that the intensification of the effects of climate change on subtropical areas and overexploited species is predicted., (© 2024. The Author(s).)

Background: The increasing consumption of seafood may bring health risks. It will be especially important for the people living along the coasts who are highly dependent on seafood for food and income., Methods: In this research, a comprehensive health risk assessment was performed on 27 species of high-consumption commercial fish sampled from stations located in Hormozgan province within the Northeast Persian Gulf. Concentrations of trace metals and their health risk were investigated., Results: Spatial distribution of trace metals in commercial fish showed central stations including Kong and Greater Tonb have higher concentrations of all trace metals except Pb. Some metals showed a significant correlation between concentrations. Our finding indicated the average concentration of all trace metals except Ni in all species was below the concentrations proposed by WHO/FAO/USEPA. EDI for all metals in all species in both adult and child age groups was lower than its RfD (oral reference dose of trace metal) showing the daily consumption of these fish does not pose any health risk and implicates seafood consumption guidelines or policies. Values of THQ for each metal and HI for all metals were lower than 1 in all commercial fish indicating the lack of non-cancerous health risk through the long-term consumption of these fish. The research found potential health risks associated with the consumption of these fish, specifically related to the metals Cr, Ni, and Cd., Conclusion: In total, health risk indices proposed eight fish as bio-indicator species of the Persian Gulf. The findings emphasize the risk management of commercial fish consumption, especially bio-indicator species, in Hormozgan province, the Northeast Persian Gulf., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

The knowledge of the geographical distribution and habitat preferences of marine species is the key to protecting marine ecosystems. Modeling the distribution of marine species through environmental variables is an essential step to understanding and reducing climate change effects on marine biodiversity and related human populations. In this study, the present distributions of commercial fishes including Acanthopagrus latus, Planiliza klunzingeri, and Pomadasys kaakan were modeled using the maximum entropy (MaxEnt) modeling technique and a set of 22 environmental variables. In total, 1531 geographical records belonging to three species were extracted from online databases Ocean Biodiversity Information System (OBIS, 829 records, 54%), Global Biodiversity Information Facility (GBIF, 17 records, 1%), and literature (685 records, 45%) during September to December 2022. The findings showed the values of area under the receiver operating characteristic (ROC) curve (AUC) above 0.99 for all species indicating the high performance of this technique to reflect the actual distribution of species. Environmental factors such as depth (19.68%), sea surface temperature (SST) (19.40%), and wave height (20.71%) were the strongest environmental predictors determining the present distribution and habitat preferences of the three commercial fish species. The Persian Gulf, Iranian coasts of the Sea of Oman, North Arabian Sea, North-East areas of the Indian Ocean, and North coasts of Australia are among the areas with ideal environmental conditions for the species. For all species, the percentage of habitats with high suitability (13.35%) was higher compared to habitats with low suitability (6.56%). However, a high percentage of species occurrence habitats had unsuitable conditions (68.58%) showing the vulnerability of these commercial fishes. Significant management strategies are needed to protect preferred habitats to minimize the effect of fishery and climate change on the population stocks of these commercial fishes., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

With the development of industries and excessive use of petroleum compounds, petroleum pollution has become a serious threat to the environment. The aim of this study was to the effect of petroleum levels on the biological activities of soil affected by phytoremediation and bioaugmentation. A surface soil sample was collected from the polluted areas around Bandar Abbas Oil Refinery Company, and the petroleum-degrading bacteria were isolated. M. yunnanensis (native) was selected among the isolated colonies for further experiment. The used soil in this study was a surface soil collected from Baghu region of Bandar Abbas, Sothern Iran, and treatments were added to soil samples. To evaluate removal of petroleum levels (0, 4, and 8%) from the soil by phytoremediation (control, sorghum, barley, and bermudagrass) and bioaugmentation (control, A. brasilense (non-native) and M. yunnanensis) and bioaugmented phytoremediation, a factorial pot experiment with completely randomized design and three replications was performed. The results demonstrated that sorghum and bermudagrass were more resistant than barley to the toxic effects of petroleum. Positive effect of bacteria on dry weight in polluted soil was greater than in the non-polluted soil. The degradation of petroleum reaches 77% in sorghum + M. yunanesis + 4% petroleum. Plants had stronger ability to degrade total petroleum hydrocarbon (TPH), while bacteria could better degrade polyaromatic hydrocarbons (PAHs). Application of bacteria and plants stimulated soil biological characteristics (dehydrogenase, arylsulfatase, lipase, bacterial population, and respiration) in polluted soil. Among measured enzymes, dehydrogenase exhibited a stronger response to petroleum levels. Four-percent level had greater irritating effect on soil biological properties. Plants and bacteria rely on differences in biological properties to attain synergy in petroleum degradation. Results indicated that M. yunnanensis has a high ability to remove petroleum from soil, and plants enhance the efficiency of this bacterium., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Bioaccumulation of trace metals in the food web demands continuous monitoring of seafood safety. Here, the food safety of commercial fish bluespot mullet Crenimugil seheli, deep flounder Pseudorhombus elevates, and Jinga shrimp Metapenaeus affinis was assessed from commercial and industrial region of the West Bandar Abbas, the North Persian Gulf, for the first time., Methods: For this purpose, concentrations of trace metals Ni, Zn, Cu, Cr, Cd, and Pb, and their health risks were investigated., Results: Results showed the average concentration of all trace metals in all species was below concentrations proposed by WHO/FAO/USEPA. The finding on risk assessment of three species indicated three species are safe for daily consumption. Long-term consumption of three species would not pose potential non-carcinogenic health risk. However, it would result in carcinogenic effects from the ingestion of trace metals Ni, Cr, and Cd., Conclusions: The data emphasizes the need for the continuous monitoring in this industrial region in the future to manage and control pollutant sources and to ensure the quality of seafood., (Copyright © 2022. Published by Elsevier GmbH.)

Harmful algal blooms (HABs) have been serious environmental problems in the Persian Gulf and Oman Sea in recent years. There has been an increase in occurrence of HABs in coastal waters of Hormuzgan Province (to the north of the Persian Gulf and Oman Sea) in recent decade, due to eutrophication as a result of human activities. In this review, HAB phenomena in coastal waters of Hormuzgan Province are summarized, including, causative species, timing and the location of blooms during a 35-year time span from 1980 to 2015. This review illustrates that 436 algal blooms have been recorded in the north of the Persian Gulf, formed by 17 species of phytoplankton; 270 of harmful dinoflagellate (Margalefidinium polykrikoides) blooms have led to huge catastrophic impacts on the economy, environment, and society. In addition, most algal blooms (49%) have occurred in the coasts of Bandar Abbas. The data in this review suggest supporting the establishment of an algal bloom monitoring and control program in the coastal waters of the northern part of the Persian Gulf and Oman Sea (Hormuzgan Province)., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

In this study, the removal of 17 selected PCB i congeners was assessed in a transformer oil-contaminated soil amended with bentonite clay powder applied at the three levels of 0, 2, and 4% and cultivated by Zea mays L. or Alternanthera sessilis L. in a pot experiment. Results showed that Z. mays and A . sessilis were able to reduce the residual concentrations of the PCB i congeners in the contaminated soil significantly ( p  < 0.05). The average reductions in the ƩPCB i due to Z. mays or A . sessilis cultivations were 34.3 and 21.4%, respectively, depending on initial soil ƩPCB i loading and plant growth period. Moreover, addition of bentonite led to significant ( p  < 0.05) enhancements in plant growth and dissipation of residual soil PCB i congeners under Z. mays and A . sessilis cultivations. Addition of 4% bentonite to the soil was found to have the greatest positive impact on PCB i removal so that average PCB i dissipations in the soil were 56.1 and 51.8% after growing Z. mays and A . sessilis , respectively. It might be concluded that the combined phytoremediation and bentonite addition is an effective technique for removing PCB i and remediating transformer oil-contaminated coarse-textured soils.

Algal bloom as a common phenomenon in the Persian Gulf and the Sea of Oman had catastrophic effects on environmental, social, economic, and human health aspects from 2008 to 2009. Since 2008, the Persian Gulf and the Sea of Oman Ecological Research Institute (PGSOERI) has monitored and managed algal blooms in the Hormuzgan coast along the northern Persian Gulf and the Sea of Oman. Management strategies have included regular monitoring of chlorophyll, water quality, and remote sensing. In this regard, relevant departments and the Regional Organization for Protection of Marine Environment (ROPME) collaborated with each other to prevent and forecast algal blooms. We reviewed historical and current monitoring, mitigation, and management systems of algal blooms in the Hormuzgan coast. In addition, complications and challenges of algal bloom monitoring and management were also discussed. Documenting algal bloom monitoring and research, improving forecasting and modeling of blooms, educating the public and fishermen, developing a cooperative monitoring framework, and controlling pollution input entering the ROPME region are the main challenges of algal bloom management in the Hormuzgan coast.

We isolated an actinobacterium, Streptomyces sp. strain SP 85 from the marine sponge Dysidea avara. Polyphasic identification of the microorganism showed that the strain SP 85 had high 16S rRNA gene similarity (99%) with Streptomyces olivaceus strain NBRC 12805, while some physiological and biochemical differences were observed. A cytotoxic compound, SP 85 was isolated from the active culture extract of the strain SP 85 by bioassay-guided purification over silica gel column chromatography, preparative TLC, and HPLC. The structure elucidation based on the spectroscopic analysis, including UV, ESI-MS, and 13 C NMR data revealed that SP 85 compound is an analog of anti-tumor drug, "olivomycin A". The SP 85 compound showed high cytotoxic activity against three human cancer cell lines, including SW480, HepG2, and MCF7 with IC 50 values of 16, 93, and 78 nM, respectively. SP 85 exhibited significantly (2-10 times) higher cytotoxicity against the tumor cell lines in comparison with HUVECs as the normal cell line, which also induced apoptosis in the tested cancerous cell line. This is the first report on the production of an "olivomycin A" derivative by a sponge-associated Streptomyces , showing the great potential of sponge-associated actinobacteria in producing cytotoxic natural products., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© King Abdulaziz City for Science and Technology 2019.)

Portable high-resolution gamma-ray spectrometry was carried out to determine the natural radioactivity levels in high volume surface water samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz strait to Goatr seaport, for the first time. The water samples from 36 coastal and near shore locations were collected for analysis. Analyses on the samples collected were carried out to determine (226)Ra, (232)Th and (40)K contents. The concentration of (226)Ra, (232)Th and (40)K in surface water samples ranged between 2.19 and 2.82 Bq/L, 1.66-2.17 Bq/L and 132.6-148.87 Bq/L, respectively. The activity profile of radionuclides shows low activity across the study area. The study also examined some radiation hazard indices. The external hazard index was found to be less than 1, indicating a low dose. The results of measurements will serve as background reference level for Oman Sea coastlines., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

This study aims to establish a managed sampling plan for rapid estimate of natural radio-nuclides diffusion in the northern coast of the Oman Sea. First, the natural radioactivity analysis in 36 high volume surface water samples was carried out using a portable high-resolution gamma-ray spectrometry. Second, the oceanic currents in the northern coast were investigated. Then, the third generation spectral SWAN model was utilized to simulate wave parameters. Direction of natural radioactivity propagation was coupled with the preferable wave vectors and oceanic currents direction that face to any marine pollution, these last two factors will contribute to increase or decrease of pollution in each grid. The results were indicated that the natural radioactivity concentration between the grids 8600 and 8604 is gathered in the grid 8600 and between the grids 8605 and 8608 is propagated toward middle part of Oman Sea., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Refrigerated storage is the simplest method of preserving for short time handling and storage of fish. The objective of this study was to investigate the effects of refrigerated storage on the microstructure, physicochemical (proximate composition, pH, TVB-N, LHC), microbial (total mesophilic count, TMC and total psychrotrophic count, TPC) and sensory changes of grouper (Epinephelus coioides) fillets during a 14-day period at +4 °C. The estimated TVB-N value was significantly different in all days of storage. TPC value reached to a limiting level for human consumption (10(7) micro-organism/g) after the 10th day of storage while TMC remained under the limited acceptability until 14 days. Cellular tissue damage was observed after 7 days of storage. The shelf life of grouper was approximately ~8-9 days according to the results of sensory, chemical and microbial analysis.

The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine (235)U, (238)U, (232)Th, (40)K and (137)Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of (235)U, (238)U, (232)Th, (40)K and (137)Cs in sediment samples ranged between 1.01 and 2.87 Bq/kg, 11.83 and 22.68 Bq/kg, 10.7 and 25.02 Bq/kg, 222.89 and 535.07 Bq/kg and 0.14 and 2.8 Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The relationship between sex, size (length and weight) and metal concentrations in the tissues of two commercially valuable fish species (silver pomfret, Pampus argenteus and tiger tooth croaker, Otolithes ruber) from Persian Gulf were evaluated. Concentrations of the metals in fish species ranged as follows: Mn 0.743-11.279; Cd 0.175-2.375; Pb 2.406-11.297; Zn 10.837-80.389; Fe 2.263-86.110; Cu 1.503-6.333 μg/g dry weight, respectively. Metal content in both fish varied with type of metals, organ, and sex. Results showed that, except in a few cases, significant relationships between metal concentrations and fish size were negative.

This study aims to investigate the pollution rate of heavy metals on the western seaboard of Bandarabbas in southeast Iran using a new pollution index. The bulk of the analysis was conducted on sediments, followed by selection of a few samples to perform experiments on chemical partitioning studies as well as biological accessibility. On this basis, the proportions of natural and anthropogenic elements were calculated. Finally, with regard to chemical separation results, the pollution rate was calculated based on Muller's geo-chemical index, enrichment factor, pollution index, and a new "Risk" index. Chemical separation showed the anthropogenic origin of elements are as follows: Ni(27.5%) > Zn(6.5%) > Pb(2%) > Al (0.2%). The newly developed pollution index is indicative of "low environmental pollution "for Ni.

Concentrations of cadmium, copper, and lead were determined in surficial sediments and the soft tissues (foot and gills) of swan mussel Anodonta cygnea from two sampling sites in Anzali wetland, which is an internationally important wetland registered in the Ramsar Convention. The metal contents in the mussel species from the studied region were comparable to other world areas. In most cases, the levels of the metals either fell within the range for other areas or were lower. There were significant differences between the tissues for the accumulation of Cd and Pb. Only in the case of Pb accumulation in gills significant differences between the specimens from the selected sampling sites could be observed. Age-related correlations were found in the case of Cu accumulation in foot and Cd levels in gills. No weight-dependent trend could be observed for the accumulation of the three elements. There was significant negative width-dependent relationship in the case of Cu. A significant negative correlation was also found between the maximum shell height and Cu accumulation in the gills. The only association among the elements in the selected soft tissues was found between Cd and Pb. Highly significant differences could be found between the sampling sites from the concentration of the elements in sediments point of view. The pattern of metal occurrence in the selected tissues and sediments exhibited the following descending order: Pb, Cu>Cd for gills, Cu>Pb, Cd for foot, and Cu>Pb>Cd for sediments. The mean concentrations of Cd and Pb in the sediments from the study area were higher than the global baseline values and world average shale. In the case of Cu, our results were somewhat higher than the baseline values but well below the world average shale.

Introduction: Sodium hypochlorite (NaOCl) is an effective antimicrobial irrigant, however its toxic effects and deterrent odor are not ideal. Carvacrol is an edible plant extract with anti-inflammatory and anti-bacterial properties that is effective against Enterococcus (E) faecalis. The aim of this study was to evaluate Carvacrol's antibacterial efficacy against E. faecalis bacteria as a final irrigant., Materials and Methods: Forty extracted single-rooted human teeth were utilized. After mechanical preparations, samples were randomly divided into three experimental (A, B and C) and two control groups. E. faecalis was cultured in both experimental and positive control groups. After bacterial counting in all canals, 5.25% NaOCl, 0.6% Carvacrol emulsion and MTAD were used as final irrigants in groups A, B and C respectively. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests., Results: There was no meaningful difference in bacterial reduction between groups A and B; however, group C showed significantly lower efficacy compared to other groups (P<0.05)., Conclusion: The 0.6% Carvacrol disinfects root canals effectively. It also has anti-inflammatory qualities and therefore may be an acceptable alternative for NaOCl.