In this study, coral soft tissue, skeleton and zooxanthellae, as well as their ambient sediment and seawater were analyzed for polycyclic aromatic hydrocarbons (PAHs) with a special focus on perylene. Samples were collected from two different environments: the Kharg Island, which is affected by numerous anthropogenic stressors and Larak Island, which is mainly used for recreational and fishing activities and is characterized by dense vegetation. The heaviest loadings of PAHs were observed on Kharg Island, yet higher concentrations of perylene were detected on Larak Island and it was identified as the prevailing compound in this area. Pyrogenic perylene sources were prevailing on Kharg Island, whereas the perylene on Larak Island was determined to be of natural origin. After analyzing the biological samples, higher perylene concentrations were observed in zooxanthellae than in tissue and skeleton. The lowest and the highest perylene loadings were found in the tissue and skeleton of Platygyra daedalea and Porites lutea, respectively. This applies to both reefs. We found that perylene distribution in the corals and their ambient environment follows an irregular pattern, demonstrating remarkable effects from the local inputs. The lipid content in the coral tissue and the location of the coral colony were deduced to be the main factors affecting perylene distribution in corals. On Larak Island, a significant correlation between perylene loadings in sediment and corals was observed. On Kharg Island, a strong interaction between the water column and the corals was detected. The symbiotic relationship between the corals and zooxanthellae might play the most significant role in bioconcentration and bioaccumulation of perylene. Due to the insolubility of PAHs, they could be transferred through a food chain to zooxanthellae and eventually deposited in the coral bodies.

Pollution in the Arabian Gulf has risen in recent decades due to rapid development in the region. We studied 21 elements in the liver, gastrointestinal (GI) tract and muscles of the Indian anchovy (Stolephorus indicus) to characterize bioaccumulation in this abundant forage fish. Mean concentrations (μg/g wet weight) of elements ranged as follows: Cd: 0.1–8.0; Cr: 0.1–24.0; Cu: 1.2–24.0; Ni: 0.3–76.5; Ca: 1237.0–15,270.0; S: 2966.0–7467.0; Zn: 7.1–247.0; V: 0.1–27.0; Hg: 0.04–0.18 and Sr: 8.1–191.0. Zn, Cu, Cr, and Cd in the tissues exceeded the maximum permissible limit recommended by FAO, WHO and EC. We suggest that bioaccumulation in fish could be a hazard for human consumption. Therefore, further monitoring is needed to better characterize pollutant levels in fish of higher trophic levels in the Arabian Gulf.

Musa estuary and its tributaries, located northwest of the Persian Gulf, host many industrial complexes, high-density ports, and urban areas along their coastal regions and are, therefore, constantly threatened by chemical contamination. The present study is the first to have investigated the surface sediments in six stations of the Musa estuary tributaries. The mean variations in BPA concentrations in the dry sediments of these stations ranged from 2.22 to 16.71 ng/g. Fairly high levels of BPA were found in Durragh station and its neighboring industrial sites. The lowest BPA level (2.22 ng/g) was observed in the station at the mouth of the Persian Gulf. Based on the EU risk-assessment system, the concentration levels of BPA in the sediments are in the low-risk range. Only in certain areas of the estuary were the sediments of moderate risk, and prolonged contact between ecological populations and them could cause toxicity in aquatic organisms.

Microplastics (MP), the debris that collectively refers to plastic fragments and particles of <5 mm in size within marine environments, has been the subject of interest within the past decade. Evidence of its occurrence and abundance, has been recorded in this communication after examining gastrointestinal specimens of eight commercially available fish species common to the Arabian (Persian) Gulf acquired locally from the State of Kuwait. The species studied belonged to different trophic levels, and the specimens were subjected to Micro Raman and Micro Fourier Infrared Spectroscopy (FTIR) in Attenuated Reflective Mode (ATR) to determine the presence and type of polymer of the MP. The detected MP set a president for the first time in the examined fish species within the State of Kuwait, which are of immense commercial importance. Various particles were detected, and three MP particles (fragments) were detected within the guts of Acanthopagrus latus, Eleutheronemaa tetradactylum and Lutjanus quinquelineatus. Based on the nature and behaviour of these particular fish types which prefer to stay in muddy waters and sheltered lagoons, it is suspected that common primary sources of MP (i.e. waste fragmentation) have led to passive/active intake (e.g. detritus ingestion) of these particles (fragments) by these species of fish in Kuwait.

Bilateral asymmetry is presumed to reveal the developmental variability of the fish in polluted aquatic environments. In these habitats, high-level asymmetry develops, and these fish expend more energy to balance their growth than fish that are not under an impact. A total of 210 specimens of Acanthopagrus bifasciatus, A. latus and Sparidentex hasta were collected from the marine waters of Iraq in the northwest part of the Arabian Gulf. The asymmetry was calculated for the sagittal otolith characters of length and width. Otolith width has lower asymmetry than otolith length for the three sparid fish species investigated. An increase in the value of fluctuating asymmetry with fish length was observed. This could be a pertinent indicator of pollution in the habitat.

The Persian Gulf, the most important marine ecosystem, and its islands are negatively impacted by development and pollution. Different types of pollution, especially heavy metals in these habitats, may create risks to birds, influencing reproductive performance, survival, and behaviors.Heavy metals (Cd, Pb, Cr) were analyzed in two long-lived and top food web–level sea birds, Lesser (Thalasseus bengalensis) and Greater Crested Tern (Thalasseus bergii). The research was carried out during 2018 on Nakhiloo Island, located in Dayyer-Nakhiloo Marine National Park, northeastern Persian Gulf, Iran. The nests were selected randomly, and 40 eggs of colonially-nesting terns (20 eggs T. bengalensis and 20 eggs T. bergii; a single egg per nest) were collected. The concentration of heavy metals in eggshells and egg contents was studied to investigate whether bioaccumulation varies between the eggshells and egg contents and also varies in both species. There were significant differences in the amounts of Cd between eggshell and egg content in the Greater and Lesser Crested Tern. This difference was not significant in the concentrations of Pb between the eggshell and egg content in the Tern species. Concentration of Cr did not appear to accumulate in the egg content and was below detection limit. There were significant differences in the concentrations of Cd in the eggshells and egg content between the Greater and Lesser Crested Tern. The results serve to improve understanding and to evaluate the dynamics of heavy metals in eggshells and egg content in various avian species.

Currently, microplastics are a major challenge threatening marine environment. Given little information on their prevalence in the Persian Gulf, the present study as the first comprehensive study was conducted to evaluate microplastics abundance in surface waters. Neustonic samples were collected from 15 stations along the Persian Gulf. Visually separated microplastics were categorized according to their size, shape, and color. ATR-FTIR method was used to identify the composition of polymers. Microplastics were found in all sampling stations and their density varied from 1.5 × 10³ to 4.6 × 10⁴ particle.km⁻² with a mean density of 1.8 × 10⁴ particle.km⁻². Fibers were the most dominant shape of microplastics (44.1%). Approximately 76% of the analyzed microplastics were polyethylene and polypropylene and the predominant colors of the microplastics were white and blue. Results of the study confirmed prevalence of microplastics in the Persian Gulf, and findings suggested a pressing need to investigate their effects on marine life and human health.

The Arabian or Persian Gulf is recognized as one of the warmest estuaries globally. The sea surface temperature (SST) has been utilized in several studies to gauge the global warming associated with climate change. In the current investigation we present detailed in situ SST measurements for five consecutive years (2016, 2017, 2018, 2019, 2020) in the northwest of the Gulf, specifically in Kuwait Bay. Results of data analyses were compared with the historical records for the region, revealing that the SST reached an extreme level never previously recorded either in the Gulf. The extreme SST in Kuwait Bay reached 37.6 °C, recorded by the offshore station KISR01 located in the middle of the Bay. The event was associated with heatwave, neap tides, and an extended period of Kous winds which are characterized by high humidity levels and accompanied by large-scale intermittent fish kill incidents that extended the full length of the Kuwait coastline. Several fish kill incidents were reported also at the northern edge of the Gulf along Shatt Al Arab stretch in Iraq. The species found dead during the incident varied considerably, unlike those found in the frequent summer incidents. The records presented in this study may provide evidence to the effects of global warming, aid further research, and encourage the concerned international government bodies to deliver urgent environmental policies.

Monthly mean satellite derived Chl-a, aerosols, wind, SST, PAR, and turbidity datasets were used to investigate the possible factors regulating phytoplankton variability in the Persian Gulf. The spatial correlation analysis revealed two distinct regions of SST and PAR, and a relatively uniform spatial correlation pattern of the other parameters. The cross correlation between aeolian dusts and Chl-a was significantly positive with 1–3 months offset. The pattern of spatial correlation between Chl-a and SST was positive in the shallow regions without time lag, and was negative with time offset of 3–5 months in deeper regions. The cross correlation between Chl-a and north-ward winds were positive with time lags of 1–3 months. Vertical mixing under the influence of north-ward winds in the deeper region, availability of light and nutrients in the shallow regions, and dust fertilizations over the whole area were suggested to be the major controlling factors regulating phytoplankton growth.

The presence of chemicals in marine organisms is an important issue for human health due to the growing rate of seafood consumption. Potential exposure to seven bisphenol analogues through seafood consumption was investigated in some popular seafood from the Persian Gulf. Bisphenols were analyzed by gas chromatography–mass spectrometry. Bisphenol A (BPA) and bisphenol B (BPB) were the first and second most common bisphenols in the studied samples, respectively. The highest levels of BPA (mean 13.58 ± 5.70 μg/kg.dw) and BPB (mean 10.30 ± 7.98 μg/kg.dw) were found in E.coioides species. Bisphenol F and bisphenol AF were detected only in P. armatus and L. klunzingeri, respectively. Trophic transfer investigation demonstrated that BPA and BPB were biomagnified in the studied organisms through their diet. The eco-toxicity and estrogenic risk assessment indicated that seafood consumption does not pose a health threat to consumers. However, routine monitoring of bisphenols in seafood seems to be necessary to ensure food safety.