Naturally Occurring Radioactive Material (NORM) in seawater of the northern Arabian Gulf - Baseline measurements

Metagenomes from Coastal Sediments of Kuwait: Insights into the Microbiome, Metabolic Functions and Resistome

Coastal sediments in the proximity of wastewater and emergency outfalls are often sinks of pharmaceutical compounds and other organic and inorganic contaminants that are likely to affect the microbial community. The metabolites of these contaminants affect microbial diversity and their metabolic processes, resulting in undesirable effects on ecosystem functioning, thus necessitating the need to understand their composition and functions. In the present investigation, we studied the metagenomes of 12 coastal surface sediments through whole genome shot-gun sequencing. Taxonomic binning of the genes predicted about 86% as bacteria, 1% as archaea, >0.001% as viruses and Eukaryota, and 12% as other communities. The dominant bacterial, archaeal, and fungal genera were Woeseia, Nitrosopumilus, and Rhizophagus, respectively. The most prevalent viral families were Myoviridae and Siphoviridae, and the T4 virus was the most dominant bacteriophage. The unigenes further aligned to 26 clusters of orthologous genes (COGs) and five carbohydrate-active enzymes (CAZy) classes. Glycoside hydrolases (GH) and glycoside transferase (GT) were the highest-recorded CAzymes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) level 3 functions were subjugated by purine metabolism > ABC transporters > oxidative phosphorylation > two-component system > pyrimidine metabolism > pyruvate metabolism > quorum sensing > carbon fixation pathways > ribosomes > and glyoxalate and dicarboxylate metabolism. Sequences allying with plasmids, integrons, insertion sequences and antibiotic-resistance genes were also observed. Both the taxonomies and functional abundances exhibited variation in relative abundances, with limited spatial variability (ANOVA p > 0.05; ANOSIM-0.05, p > 0.05). This study underlines the dominant microbial communities and functional genes in the marine sediments of Kuwait as a baseline for future biomonitoring programs.

Temporal trend of polychlorinated biphenyls contamination in the northwestern Arabian Gulf - Evidence from sediment records

This study provides an insight into the polychlorinated biphenyls (PCBs) inventories in the sediments of the northwestern Arabian/Persian Gulf. PCBs can be used as chemical markers that correlate with historical events in the region, to estimate the sedimentation rates in the northern Gulf, and to determine the sources of pollutants in the study area. The concentrations of PCBs were generally patchy in sediments. At Station 1 the ΣPCB concentrations generally fluctuated between 0.100 and 0.400 ng g^-1 dw throughout the depositional history measured in a sediment core. There were four peaks in the ΣPCB profile corresponding to 1969, 1979, 1983 and 1991. Station 2 showed a prominent peak at depth of 25 cm. The concentrations of the ΣPCBs and ΣICE congeners at this depth were 28 and 12 ng g^-1 dw respectively. Concentrations then dropped dramatically thereafter by a factor of 4. The ΣPCB concentrations at Station 3 were very low compared to the concentrations measured at Stations 1 and 2. The PCB concentration in Core 4 which was taken from open waters was 2-3 orders of magnitude lower than those in the other coastal cores. However, a 1990-91 peak was omnipresent in these cores. There is no record of PCB production within the Gulf region, and PCB releases into the Kuwait marine environment are likely to originate from their use in products. These maxima in early-1990s can be correlated to inputs from war-related activities, including the reported destruction of PCB-containing transformers and military equipment during the occupation of Kuwait. None of the recent sediment core sections at the four stations had a ΣPCB concentration near the effects range-median (ERM) concentration of 180 ng g^-1, or permissible exposure limits (PEL) of 189 ng g^-1, or were above the effect range-low (ERL) values of 22.7 ng g^-1.

Baseline concentrations of pharmaceuticals in Kuwait's coastal marine environment

This study was carried out to provide baseline information on the concentrations of pharmaceuticals in Kuwait's coastal waters. Samples were collected over four sampling campaigns from various outfalls that occasionally discharged water into the marine environment and analyzed for a range of pharmaceuticals including analgesic/anti-inflammatories, antibiotics, anticoagulant, antidiabetic, antihelmintics, antihypertensives, antiplatelet agent, asthma medication, β-blocking agent, calcium channel blocker, diuretic, histamine H1 and H2 receptor antagonist, lipid regulators/cholesterol-lowering, prostatic hyperplasia, psychiatric drug, sedation and muscle relaxant, synthetic glucocorticoid, tranquilizer and x-ray contrast media. The levels varied between the detection limits of the method and a maximum of 28,183 ng/L for analgesics/anti-inflammatories. The highest pharmaceutical concentrations were in samples collected during the September campaign, possibly linked to the increased prescription of these medications to treat infectious diseases and flu prevalent in Kuwait during the winter months. The spatial variation is concentration is evident with KISR site being most polluted as hospital wastewater is discharged at the site. This study provides the first dataset on the concentrations of pharmaceuticals in the seawater in Kuwait and possibly the wider Arabian Gulf. Kuwait's coastal water pharmaceutical concentrations derived from this study exceed those reported from the Spanish coast, the Hong Kong harbour, the Bohai and the Yellow seas. More studies are needed to evaluate the environmental impact that these residues may have on non-target organisms.

Petroleum hydrocarbon pollution in sediments from the Gulf and Omani waters: Status and review

This review presents the spatio-temporal distribution of petroleum hydrocarbons including total petroleum hydrocarbon (TPH), total organic carbon (TOC), total aliphatics, unresolved complex mixture (UCM), polycyclic aromatic hydrocarbons (PAHs), and total aromatic hydrocarbons in marine sediments of the Gulf (Iraq, Iran, Kuwait, Saudi Arabia, Bahrain, Qatar, United Arab Emirates and Oman). The TPH ranged between 0.134 and 48,018 μg g^-1 dw where 10-15 μg g^-1 dw was considered as a background concentration. The TOC levels were between 0.04 and 14.96% with a mean concentration of 1.154 ± 0.523%. Total aliphatic hydrocarbon levels were reported between 0.1 and 76 μg g^-1, the 2005 levels that had the largest spatial coverage were between 0.1 and 4.4 μg g^-1. The unresolved complex mixture was very variable post Gulf War but by 2005 most of the Gulf War artifacts had decreased and the levels were between 1.5 and 73.5 μg g^-1. The ƩPAHs in bottom sediments by 2005 were between 0.3 and 3450 ng g^-1. The total aromatics were limited in spatial extent and varied between 1.0 and 14,000 μg g^-1. Most of the locations with elevated contamination levels were near point sources, e.g. oil facilities and ports, and these sites could be categorized as chronically contaminated by oil. This review highlights the paucity of the data both in terms of the spatial extent and temporal coverage, and with several Gulf states undergoing large-scale coastal developments and offshore oil exploration, it will be prudent to undertake regular monitoring of the petroleum hydrocarbons to ensure effective ecosystem functioning as well as seafood and drinking water safety in the Gulf region. The spatial distribution also highlights the lack of uniformity in assessments and the need to support marine pollution assessments in the Gulf countries.

A review of radioactivity in the Gulf region

The region around the Gulf is moving toward a nuclear energy option with the first nuclear power plant now operational in Bushehr, Iran. Others are soon to be commissioned in Abu Dhabi and in Saudi Arabia. For this reason, radiological safety is becoming a prime concern in the region. This review compiles published data on radionuclide concentrations in seawater, sediment, and biota that have been analyzed in the Gulf countries, along with spatial distribution patterns to enable a synoptic view of the available datasets. The seawater concentrations of ³H, ²¹⁰Po, ²¹⁰Pb, ¹³⁷Cs, and ⁹⁰Sr varied between 130 and 146, 0.48-0.68, 0.75-0.89, 1.25-1.38, 0.57-0.78 mBq L^-1, respectively. The ²²⁶Ra concentration in seawater varied between 0.26 and 3.82 Bq L^-1. Extremely high ⁴⁰K concentrations between 132 and 149 Bq L^-1 have been reported from the Iranian coast compared to 8.9-9.3 Bq L^-1 from the western side of the Gulf. Concentrations of ⁴⁰K, total ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ^239+240Pu, and ²³⁸Pu were determined in sediment and ranged between 353 and 445, 23.6-44.3, 1.0-3.1, 4.8-5.29, 17.3-20.5, 15-16.4, 28.7-31.4, 1.26-1.30, 29.7-30.0, 0.045-0.21 and 0.028-0.03 Bq kg^-1 dry weight, respectively. Significantly higher ¹³⁷Cs values have been reported from the Iranian coast compared to the western coast of the Gulf. Whole fish concentrations of ⁴⁰K, ²²⁶Ra, ²²⁴Ra, ²²⁸Ra, ¹³⁷Cs, ²¹⁰Po and ⁹⁰Sr ranged between 230 and 447, 0.7-7.3, <0.5-6.6, <0.5-15.80, <0.17, 0.88-4.26 and 1.86-5.34 Bq kg^-1 dry weight, respectively. ²¹⁰Po was found to be highly concentrated in several marine organisms with the highest ²¹⁰Po concentration found in the clam Marcia marmorata (193.5-215.6 Bq kg^-1 dry weight). The review highlights the overall paucity of data and inconsistencies in the measurement of radionuclides throughout the Gulf region. Further, since the region is moving toward nuclear energy to meet its increasing energy demand, and coupled with the environmental effects from offshore oil exploration and the heavy impact of climate change, there is a pressing need to undertake a comprehensive marine radioactivity monitoring and assessment effort by conducting a joint cruise in the Gulf with participation of all the adjoining countries. Several recommendations on sampling marine matrixes in the Gulf are given with the aim of improving comparability of radionuclide data from the various studies undertaken in the Gulf region.

An assessment of microplastics threat to the marine environment: A short review in context of the Arabian/Persian Gulf

Microplastics are recognised as a (persistent) pollutant and are believed to be ubiquitous in the marine environment. The importance of this issue is evident from the large number of technical publications and research efforts within the past decade. However, the Arabian (Persian) Gulf region has few reported datasets in spite of being an area with excessive plastic use and a hefty generation rate of plastic solid waste. This communication aims at stimulating a discussion on this topic focusing on the available regional and international datasets, along with the environmental conditions that are likely to contribute to the disintegration and transport of the plastic debris rendering it as microplastic. This work also highlights some of the constraints in sampling techniques, identification methods, and the reported units of microplastics. Most studies employ neuston nets of variable dimensions that samples different thicknesses of surface water, which also posses a major constraint in standardising field sample collection. Extrapolation of a trawl to units such as particles.km^-2 without considering the fact that neuston nets collect three-dimensional samples, is also another aspect discussed in this communication. This study also intends to initiate a discussion on standardising the practices across the region to enable an intercomparison of the reported data. In addition, it calls for a comprehensive assessment using the standardized methodology for putting a mitigation plan for microplastics as a potential threat detected in environmental sinks.

Microplastic particles in the Persian/Arabian Gulf - A review on sampling and identification

Microplastics are ubiquitous, persistent pollutants that are reported in abundance within the marine environment. Their presence in seawater and marine sediments poses a legitimate environmental and ecological concern for toxicity and food chain transfer via marine organisms. Their capability for sorption of other hydrophobic contaminants and the inability of the wastewater treatment plants to completely remove them pose additional risks. This review highlights the methodologies for sampling, sample preparation, and identification used in the Persian/Arabian Gulf region, which is possibly one of the least studied marginal seas with only sixteen papers published on microplastics. The review highlights the several orders of magnitude variations in microplastic concentrations among different studies; e.g. in seawater, only 12 microplastic particles were reported from 40 transects of one km length in Kuwait to 0.71 microplastics m^-3 in Qatar. Concentrations in beach sediments also show the significant difference between the northern and southern Gulf coasts, with 13 particles in 24 samples reported in Qatar, and 15 particles within 44 samples across Kuwait, to 3252 ± 2766 particles m^-2 from Bandar Abbas, Iran. The biota samples also show similar variances, with only three particles identified from 87 gut samples in Kuwait to 828 particles in 58 samples that include 46 fish and 12 shrimps from Iran. Some extremely high concentrations in biota are also reported from Iran, with concentrations as high as 0.251 particles g^-1 of muscle and 0.931 particles g^-1 in gills. It is evident that there is no consensus in the Gulf region on the sampling techniques (mesh size of plankton nets and sieves), use of fluidization solutions and very different units used in data reporting such as particles m^-3 and particles m^-2 in water samples. In sediments units like particles g^-1 and particles m^-2 have been used, and for biota it is the number of particles present in the sample, while others have quantified data as particles g^-1 of tissue. Considering the higher densities of PET, PVC, nylon and polyester than seawater, they are likely to migrate downwards into marine sediments, a transfer process that has not been studied in detail. Thus the review underscores the need to adopt harmonized protocols for microplastic studies in the region, and identifies certain aspects of microplastics that require further study.

Establishment of a NORM baseline for selected seafood in the Gulf of Mexico

Naturally occurring radioactive material was characterized in selected seafood samples from three areas in the Gulf of Mexico. Relatively desirable and abundant fish such as Red Snapper, Red Drum, Northern Whiting, and Spotted Trout as well as oysters were collected and analyzed using gamma spectroscopy to determine the concentration of ²²⁸Ra, ²²⁶Ra, and ⁴⁰K. Average total activity concentration from these radionuclides were 0.9 ± 0.6, 1.6 ± 1.2, and 132 ± 57 Bq kg^-1 respectively, in the edible portion of wet weight samples. The results were consistent with previous studies for other bodies of water. A small but statistically significant increase in ²²⁶Ra was found in comparison to similar research performed 20 years prior. These measurements provide a reasonable baseline for the examined species from the Gulf of Mexico.

Concentrations of selected radionuclides and their spatial distribution in marine sediments from the northwestern Gulf, Kuwait

This study focuses on creating a baseline for ⁴⁰K, ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ^239+240Pu and ²³⁸Pu in marine sediments in the northwestern Gulf. The respective measured concentration ranges were 386-489, 32.3-48.8, 1.5-2.9, 4.53-5.42, 18.3-23.1, 18.8-23.0, 22.3-30.5, 0.99-1.33, 25.6-34.8, 0.30-0.93, and 0.0008-0.00018Bqkg^-1. The levels of these radionuclides are generally comparable to values reported for other marine waters in the northern hemisphere. The ¹³⁷Cs activity in the Gulf sediments offshore Kuwait is an order of magnitude lower compared to sediments from northeastern Iran. Other than that finding, no hot spots were observed in sediments adjacent to power and desalination plants, oil and gas industrial activities or wastewater treatment facilities. These data will serve as a baseline to gauge possible future inputs of radionuclides in the northern Gulf. The calculated average ratio of ²³⁵U/²³⁸U activity in the area is in agreement with the reported figure of the natural uranium ratio, suggesting the absence of depleted uranium (DU) at all the stations. The low concentration of ^239+240Pu suggests that there is no significant source of plutonium except that from atmospheric fallout from weapon testing and possible dry deposition via long-range dust transport.