Assessment of parent and alkyl -PAHs in surface sediments of Iranian mangroves on the northern coast of the Persian Gulf: Spatial accumulation distribution, influence factors, and ecotoxicological risks.

Spatial patterns, potential origins, and ecotoxicological risk of alkylated (APAH) -and parent -(PPAH) polycyclic aromatic hydrocarbons (PAHs) were studied in mangrove surface sediments along the northern coasts of the Persian Gulf, Iran. The mean total concentrations (ngg-1dw) ∑32PAH, ∑PPAHs and ∑APAHs in sediments were 3482 (1689-61228), 2642 (1109-4849), and 840 (478-1273), respectively. The spatial variability was similar among these PAH groups, with the highest levels occurring in Nayband National Marine Park (NNMP). Physicochemical environmental factors, such as sediment grain size, and total organic carbon (TOC) contents, are significant factors of PAH distribution. These findings suggest that PAH pollution level is moderate-to-high, supporting the current view that mangrove ecosystems are under intensive anthropogenic impacts, such as petrochemical, oil and gas loads, port activities, and urbanization. Non-parametric multidimensional scaling (NPMDS) ordination demonstrated that NNMP mangrove is the critical site exhibiting high loading of PAH pollutants. Here, for the first time in this region, Soil quality guidelines (SQGs), Toxic equivalency quotient (TEQ), Mutagenic equivalency quotient (MEQ), and composition indices comprising Mean maximum permissible concentration quotient (m-MPC-Q), and Mean effect range median quotient (m-ERM-Q) methods were used to have a comprehensive risk assessment for PAH compounds and confirmed medium-to-high ecological risks of PAHs in the study area, particularly in the western part of the Gulf, highlighting the industrial impacts on the environment.

Insights into bioaccumulation and bioconcentration of potentially toxic elements in marine sponges from the Northwestern Mediterranean coast of Morocco.

The present research aimed to investigate the concentrations and patterns of six potentially toxic elements (PTEs) in three common sponge species collected along the Moroccan Mediterranean coast, as well as their levels in ambient seawater and sediments. Distinct inter-species variability in PTEs bioaccumulation was observed among the three species, suggesting that sponges have distinct selectivity for assimilating PTEs from the surrounding environment. C. crambe had a higher enrichment capacity for Cu, As, Cr and Ni, while P. ficiformis and C. reniformis exhibited the highest concentration of Cd and Pb, respectively. Interestingly, a similar spatial distribution patterns of PTEs was observed in the three media, with high values occurring in Tangier and Al-Hoceima locations. Overall, our results confirm that sponges reliably reflect the bioavailability of PTEs in their immediate environment, especially C. crambe, whose PTE tissue contents were highly and positively correlated with the contents of all PTEs in the sediments.

Ecotoxico Linking of Phthalates and Flame-Retardant Combustion Byproducts with Coral Solar Bleaching.

Persian Gulf coral reefs are unique biota communities in the global sunbelts in being able to survive in multiple stressful fields during summertime (>36 °C). Despite the high-growth emerging health-hazard microplastic additive type of contaminants, its biological interactions with coral-algal symbiosis and/or its synergistic effects linked to solar-bleaching events remain unknown. This study investigated the bioaccumulation patterns of polybrominated diphenyl ether (PBDE) and phthalate ester (PAE) pollutants in six genera of living/bleached corals in Larak Island, Persian Gulf, and their ambient abiotic matrixes. Results showed that the levels of ∑18PBDEs and ∑13PAEs in abiotic matrixes followed the order of SPMs > surface sediments > seawater, and the cnidarian POP-uptake patterns (soft corals > hard corals) were as follows: coral mucus (138.49 ± 59.98 and 71.57 ± 47.39 ng g-1 dw) > zooxanthellae (82.05 ± 28.27 and 20.14 ± 12.65 ng g-1 dw) ≥ coral tissue (66.26 ± 21.42 and 34.97 ± 26.10 ng g-1 dw) > bleached corals (45.19 ± 8.73 and 13.83 ± 7.05 ng g-1 dw) > coral skeleton (35.66 ± 9.58 and 6.47 ± 6.47 ng g-1 dw, respectively). Overall, findings suggest that mucus checking is a key/facile diagnostic approach for fast detection of POP bioaccumulation (PB) in tropical corals. Although studied corals exhibited no consensus concerning hazardous levels of PB (log BSAF < 3.7), our bleaching evidence showed soft corals as the ultimate "summer winners" due to their flexibility/recovering ability.

A potential threat to the coral reef environments: Polybrominated diphenyl ethers and phthalate esters in the corals and their ambient environment (Persian Gulf, Iran).

Pollution of the surrounding habitat poses one of the biggest threats to the coral health and even survival. This study focuses on the occurrence, distribution, bioaccumulation and bioconcentration of polybrominated diphenyl ethers (PBDEs) and phthalate esters (PAEs) in corals, their zooxanthellae and mucus, as well as in their ambient environment in Larak coral reef (Persian Gulf) for the first time. The highest concentrations of the pollutants were recorded in mucus, followed by zooxanthellae, tissue and skeleton. Soft corals with higher lipid content contained more PBDEs and PAEs. Pollutants were both efficiently bioconcentrated from water and bioaccumulated from the ambient sediment, albeit bioconcentration played the most prominent role. Elevated PBDEs and especially PAEs concentrations were detected in the skeletons of the bleached corals if compared to the skeleton samples of the non-bleached individuals.

Chlorinated paraffins (SCCPs and MCCPs) in corals and water-SPM-sediment system in the Persian Gulf, Iran: A potential global threat for coral reefs.

Swift degradation of the coral reef ecosystems urges the need to identify the reef decline drivers. Due to their widespread use, bioaccumulative and toxic characteristics, chlorinated organic compounds, such as chlorinated paraffins (CPs), are regarded as specific pollutants of concern. Yet little is known about the occurrence of CPs in the coral reef ecosystems. This study focuses on the short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs). Their distribution and congener pattern were investigated in the water-SPM-sediment system and in the corals of the Larak coral reef for the first time. Chlorinated paraffins were detected in all the coral species. Their total loadings ranged from 42.1 to 178 ng g-1 dw in coral tissue, from 6.0 to 144 ng g-1dw in the skeleton, and from 55.0 to 240 ng g-1dw in zooxanthellae. Soft corals were found to accumulate more CPs than Scleractinian corals. Zooxanthellae and mucus accumulated more CPs than tissue and skeleton. In most cases, congener group patterns were dominated by C13 (for SCCPs) and C17 (MCCPs) groups, respectively. The congener patterns of CPs altered to some extent between mucus and the remaining coral compartments. High loadings of CPs were detected in the skeleton of the bleached corals. Moreover, a significant negative correlation between the levels of CPs and the symbiodinium density was observed.

Emerging POPs-type cocktail signatures in Pusa caspica in quantitative structure-activity relationship of Caspian Sea.

The Caspian seal Pusa caspica is the only endemic mammalian species throughout the Caspian Sea. This is the first report on risk assessment of persistent organic pollutants (POPs) in Caspian seals by age-sex and tissue-specific uptake, and their surrounding environment (seawater, surface sediments, and suspended particulate matters, SPMs) in the Gorgan Bay (Caspian Sea, Iran). Among the quantified 70 POPs (∑35PCBs, ∑3HCHs, ∑6CHLs, ∑6DDTs, ∑17PCDD/Fs, HCB, dieldrin, and aldrin), ∑35PCBs were dominant in abiotic matrices (48.80% of ∑70POPs), followed by HCHs > CHLs > DDTs > PCDD/Fs > other POPs in surface sediments > SPMs > seawater, while the toxic equivalent quantity (TEQWHO) exceeded the safe value (possible risk in this area). In biota, the highest levels of ∑70POPs were found in males (756.3 ng g-1 dw, p < 0.05), followed by females (419.0 ng g-1 dw) and pups (191.6 ng g-1 dw) in liver > kidney > muscle > blubber > intestine > fur > heart > spleen > brain. The positive age-related POPs declining correlation between mother-pup pairs suggested the possible maternal transfer of POPs to offspring. The cocktail toxicity assessment revealed that Caspian seals can pose a low risk based on their mixed-TEQ values. Self-organizing map (SOM) indicated the non-coplanar PCB-93 as the most over-represented functional congener in tissue-specific POPs bioaccumulation. Quantitative toxicant tissue-profiling is valuable for predicting the state of mixture toxicity in pinniped species.

Positive matrix factorization receptor model and dynamics in fingerprinting of potentially toxic metals in coastal ecosystem sediments at a large scale (Persian Gulf, Iran).

Effective pollution control and remediation strategies are the key to providing a major progress in conservation of coastal and marine biodiversity. For the development of such strategies, quantitative assessment of potentially toxic metals (PTMs) and the accurate identification of the pollutant sources are essential. In this study, we seek to find out spatial PTMs distribution in the coastal sediments of the Persian Gulf (Iran), to assess the potential eco-environmental risks and to identify the metal pollution sources. Total and fraction analysis indicated considerable metal (Zn, Cu, Mn, Fe, Al, Hg, Pb, Cd, As, Cr, Co, Ni and V) pollution levels, albeit in most cases PTMs were predominantly associated with the oxidizable and residual fractions. The obtained PTMs concentrations were in the range of 22.8 - 156.3, 16.6 - 161.9; 2.7 - 88; 10.4 - 107.3; 1.1 - 35.8; 0.8 - 27.9; 0.1 - 1.3; 1.1 - 21.3; 0.04 - 1.9 mg.kg-1 for V, Ni, Cu, Zn, Cr, Co, Hg, Pb, and Cd, respectively. The combined PTM-PCA-PMF modeling approach identified four main metal sources (anthropogenic, vehicle-related, agricultural and lithogenic) in the study area. Several recognizable 'hot-spots' with extremely high metal concentrations were observed in the spatial metal pollution patterns. Some of those locations were predominantly affected by the nearby industrial activities, while others have demonstrated contributions from several sources - not only anthropogenic, but also agricultural and vehicle-related. The same spots of elevated pollution were found to demonstrate higher potential eco-environmental risk. Various indexes indicated more or less similar trends: the eco-environmental risk was gradually increasing towards the northwestern part of the study area with several peaks in the central and eastern parts directly affected by the nearby industrial activities.

Biomonitoring of perylene in symbiotic reef and non-reef building corals and species-specific responses in the Kharg and Larak coral reefs (Persian Gulf, Iran): Bioaccumulation and source identification.

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.

Large-scale evaluation of deposition, bioavailability and ecological risks of the potentially toxic metals in the sediment cores of the hotspot coral reef ecosystems (Persian Gulf, Iran).

Coral reefs of the Persian Gulf are vulnerable to the potentially toxic metals (PTMs) accumulated in the ambient sediments. Nonetheless, few studies have investigated the PTMs pollution and risk in the hotspot coral ecosystems of the Persian Gulf at a large-scale. Hereupon, this study focused on the PTMs contamination, their potential ecological risks, historical depositions, geochemical controls and the plausible pollution sources in the core sediments (0-40 cm) collected from the ten coral ecosystems of the Persian Gulf, Iran. Both total and fraction analysis indicated considerable metal pollution levels. Contamination was steadily decreasing towards the bottom of the sediment core, revealing the impact of a recent anthropogenic input. High metal association with the exchangeable and other mobile fractions was observed, indicating their high bioavailability. Of all the elements analyzed, toxic metals Cd, Hg and As exhibited the highest potential ecological risk (RI). Site rank index (SRI), modified degree of contamination (mCd), and contamination severity index (CSI) based approaches identified stations ST5, ST9 and ST10 as the most contaminated sites of the study area. The same stations were also found to possess considerable ecological risk. Principal component analysis (PCA) revealed that the stations located in the zone of the highest anthropogenic impact contain pollution sources for all the metals analyzed, whereas areas with low anthropogenic activity are mainly affected by the river runoff and urban emissions.

Dietary intake of polycyclic aromatic hydrocarbons (PAHs) from coral reef fish in the Persian Gulf - Human health risk assessment.

The present study investigated accumulation of petrogenic polycyclic aromatic hydrocarbons (∑39PAHs) in the livers and muscles of three coral-reef fish (50 specimens) from the Persian Gulf, Kharg Island (Iran), specifically Lethrinus microdon (n = 18), Lutjanus argentimaculatus (n = 17), and Scomberomorus guttatus (n = 15). For all fish, PAHs originated mostly from petroleum and combustion sources. Concentrations of ∑39PAHs were 1004 ngg-1 freeze-dried weight (fdw) and 1390 ngg-1 fdw for liver and muscle, respectively. The biota-sediment accumulation factor of 20,181 and equivalent concentrations of ∑PAHs (liver) were highest for L. argentimaculatus. Most of the abundant PAHs identified were low molecular weight (LMW-PAH) (liver > muscle) with 2-3 aromatic ring. Results for the human health risk assessment concluded the probability of PAHs intake via fish consumption was considerable in this area (lifetime cancer risk (ILCR) > 1 × 10-5; hazard quotients (HQs) > 1; hazard index (HI) ≈6; the excess cancer risk (ECR) > 1 × 10-6) and, therefore, comprehensive management and long-term monitoring is needed.

Steroid Fingerprint Analysis of Endangered Caspian Seal (Pusa caspica) through the Gorgan Bay (Caspian Sea).

The profile of steroid congeners was evaluated in Caspian seals Pusa caspica by age, sex, and tissue-specific bioaccumulation, and compared with that of abiotic matrices (seawater, surface sediment, and suspended particulate materials, SPMs) from Miankaleh Wildlife/Gorgan Bay, (Caspian Sea, Iran). To identify the level of human fecal contamination, ∑25 sterol congeners were measured in all abiotic/biotic samples, revealing coprostanol, a proxy for human feces, as the most abundant sterol (seawater: 45.1-20.3 ng L-1; surface sediment: 90.2-70.3 ng g-1 dw; SPMs: 187.7-157.6 ng g-1 dw). The quantification of ∑25 sterols in seals followed the order of brain > liver > kidney > heart > blood > spleen > muscle > intestine > blubber > fur, and in both sexes coprostanol level (8.95-21.01% of ∑25s) was higher in blubber and fur, followed by cholesterol in brain, liver, kidney, heart, and blood, cholestanone in intestine and muscle, and ß-sitosterol in spleen. Though no age/sex differentiation was observed, the mean concentration of ∑25s was higher in male than females and pup. Different diagnostic ratios revealed sterols originating from human and nonhuman sewage sources. Findings pinpoint the urgent necessity to investigate the ecotoxicity of fecal sterols in mammals, and consequent implications for human health.

First report on polybrominated diphenyl ethers in the Iranian Coral Islands: Concentrations, profiles, source apportionment, and ecological risk assessment.

Coral reefs are challenged by multiple stressors due to the growing industrialization. Despite that, data on their environment are still scarce, and no research is yet performed on polybrominated diphenyl ethers in the Persian Gulf area. Seeking to fill in this gap, the present study aims to determine spatio-vertical distributions, source apportionment and ecological risk of polybrominated diphenyl ethers in the sediment cores and seawater samples from ten coral reef Islands in the Persian Gulf, Iran. Σ12PBDEs concentrations ranged from 0.42 ± 0.04 to 47.14 ± 1.35 ng g-1 dw in sediments, and from 1.17 ± 0.06 to 7.21 ± 1.13 ng L-1 in seawater. The vertical polybrominated diphenyl ethers distribution varied significantly among the sampling stations and different depths with a decreasing trend towards the surface and peaks around 12-20 cm. Both in the seawater and sediment samples, elevated polybrominated diphenyl ethers loadings were observed in highly industrialized areas. Deca-bromodiphenyl ether-209 was the predominant congener along the sediment cores, whereas Tetra-bromodiphenyl ether-47 and Penta-bromodiphenyl ether-100 dominated in seawater samples. Commercial Deca-bromodiphenyl ether mixture was found to be the major source of polybrominated diphenyl ethers. Penta-bromodiphenyl ether was revealed to be the major ecological risk driver in the study area: it posed medium to high-risk quotient to sediment dwelling organisms. This study indicated that coral reefs are playing an important role in retaining polybrominated diphenyl ethers and highlighted the need to manage polybrominated diphenyl ethers contamination in the coral reef environment.

Historical sedimentary deposition and ecotoxicological impact of aromatic biomarkers in sediment cores from ten coral reefs of the Persian Gulf, Iran.

The present study determines the levels, vertical distributions, source apportionment and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in ten sediment cores of coral reef in the Persian Gulf, Iran, one of the important oil polluted marine areas in the world. The main purpose of this study was to determine the spatio-vertical distribution pattern of PAHs pollution at the four hot spot zones on the Gulf: dense industrial, medium industrial, urbanized and non-impacted zones over the past few years. Sediment quality and ecological risk were also assessed in order to determine the pollutants of concern. In detail, 23 parent (PPAHs) and 16 alkylated PAHs (APAHs), along with retene and perylene, were determined in sediment cores (0-40 cm depth). The vertical distribution of all PAHs showed a wide variation among sampling stations and depths, with a decreasing trend of concentration from surface to bottom, and a peak at 12 cm. Total concentrations of PPAHs and APAHs ranged from 35 to 1927 ng g-1 dw and 19 to 1794 ng g-1 dw respectively, with the highest concentrations at the industrial zone. The diagnostic ratio for PAHs and perylene (3 to 1277 ng g-1 dw) indicated mixed sources of PAHs, with dominance of petrogenic origins at the industrial zone and natural diagenetic inputs, respectively. The PAH concentration depicted a significant decreasing trend along the length of the core with an abrupt increase within the core length 12-20 cm. Temporal variations in contaminants can be linked to economic, coastal developments and industrial growth. Overall, the baseline data on geographical distribution, congener profiles, sources and vertical deposition of PAHs in the Persian Gulf area would be useful to establish proper monitoring plans for this sensitive ecosystem.

First polychlorinated biphenyls (PCBs) monitoring in seawater, surface sediments and marine fish communities of the Persian Gulf: Distribution, levels, congener profile and health risk assessment.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that, due to their high toxicity, lipophilic property and widespread dispersal in the global environment, present a danger for human health and ecological systems. Although the inventory and use of PCBs are extensively reported worldwide, the status of PCBs in Iran is still unknown. In this study, the concentrations of PCBs were determined in the environmental matrices and in five commercially important fish species from Larak coral Island, Persian Gulf, Iran, in winter and summer 2015. A positive correlation was found among PCBs levels and congeners profiles in seawater (0.97-3.10 ng L-1), surface sediments (2.95-7.95 ng g-1dw) and fish samples (7.20-90.19 ng g-1dw), indicating fish as suitable bioindicator of environmental PCBs contamination. In all matrices, a high contribution of light and medium chlorinated congeners was detected in both seasons. In fish, the higher PCBs levels were found for both sexes in both seasons in liver and kidney than other tissues (skin, gonad, muscle) due to their high lipid content and PCBs lipophilicity. More importantly, the risks for human health associated with fish consumption were also evaluated, and it was found that all the toxicity indices measured for PCBs were within the World Health Organization (WHO) permissible limit of food consumption. However, it is highly recommended to inform the local population about potential risks attributable to dietary incorporation of locally caught fish, and establish a surveillance monitoring programme on PCBs in this region.

Distributions and compositional patterns of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in three edible fishes from Kharg coral Island, Persian Gulf, Iran.

This is the first report on bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and their derivatives (oxygen, nitrogen, sulfur, hydroxyl, carbonyl and methyl-containing PAHs) in three edible marine fishes, namely Lutjanus argentimaculatus, Lethrinus microdon and Scomberomorus guttatus, from Kharg Island, Persian Gulf, Iran. The concentrations (ng g-1dw) of Σ39PAHs resulted significantly higher in fish liver than muscle, with the PAH composition pattern dominated by low molecular weight compounds (naphthalene, alkyl-naphthalenes and phenanthrene). The highest mean concentrations of ∑9 oxygenated and ∑15 hydroxylated PAHs (ng g-1dw) were found ound in L. microdon and L. argentimaculatus, respectively, while the lowest values in S. guttatus. Additionally, the highest mean concentrations of Σ5 carbonylic PAHs (ng g-1dw) were found in L. argentimaculatus, followed by L. microdon. The PAHs levels and distribution in fish liver and muscle were dependent on both the Kow of PAHs congeners and fish lipid contents. Overall, the present findings provide important baseline data for further research on the ecotoxicity of PAHs in aquatic organisms, and consequent implications for human health.

First report of geochemical fractionation distribution, bioavailability and risk assessment of potentially toxic inorganic elements in sediments of coral reef Islands of the Persian Gulf, Iran.

Metal contamination is a serious environmental concern in the Middle East. Herein, geochemical fractionation distribution and potential sources of thirteen metals (Fe, Al, Mn, Zn, Cu, Co, Cr, Ni, V, As, Hg, Pb and Cd) were investigated in sediments from ten coral reef Islands in the Persian Gulf, Iran. To properly assess availability and mobility of elements, enrichment factor (EF), pollution load index (PLI), pollution index (PI), contamination index (CI), sediment pollution index (SPI) and ecological risk assessment were provided. Sediment grain size showed an outstanding role in controlling the levels of potentially toxic inorganic elements (PTIEs). The highest values of total organic matter (TOM) were detected in Kharg and Lavan Islands. Different metals fractionation distribution was found across sites. As was noticed in carbonate (F2), exchangeable (F1), Fe-Mn oxy-hydroxide (F3), organic (F4) and residual (F5) fractions, Hg primarily associated with F2 and F1, whereas Pb and Cd with F2, followed by F1, F3, F5 and F4. Conversely, Ni and V accumulated in F1, suggesting their high mobility and bioavailability, and thus environmental risk to aquatic biota. All metals (except Al, Fe and As) had geological and anthropogenic sources. Based on modified risk assessment analysis, the sediments from Kharg, Lavan, Siri and Lark Islands showed medium adverse effects. Overall, results from this study corroborate that petroleum industry is the main source of pollution of PTIEs in the Persian Gulf, and offer a scientific basis for monitoring and preventing metal pollution in the environment.

First record of bioaccumulation and bioconcentration of metals in Scleractinian corals and their algal symbionts from Kharg and Lark coral reefs (Persian Gulf, Iran).

Metal pollution is nowadays a serious threat worldwide for ecosystem and human health. Despite that, there is still a paucity of data on metal impact on coral reef ecosystems. Herein, the levels of eleven metals (Mn, Zn, Cu, Cr, Co, Ni, V, As, Cd, Hg, Pb) were assessed in surface sediments, seawater samples, Scleractinian corals (tissue and skeleton) and their algal symbionts collected from Kharg and Lark coral reefs in the Persian Gulf, Iran. At Kharg, surface sediments and seawater showed higher concentrations of metals than Lark, attributable to the higher metal loads and petrochemical activities in the area. Sediment quality guidelines indicated Hg as a serious threat to biota both at Kharg and Lark. Accordingly, metals bioaccumulation and bioconcentration was higher in corals from Kharg relatively to Lark Island. Interestingly, as supported by values of BCFs and BSAFs, metal accumulation was higher in coral tissues in respect to skeletons, and in zooxanthellae relatively to coral tissues at both coral reefs. Differential metal bioaccumulation was found among Scleractinian species, indicating that corals have distinct selectivity for assimilating metals from ambient sediments and seawater. Overall, metal accumulation in corals and zooxanthellae is an appropriate tool for environmental monitoring studies in coral reefs. Noteworthy, the use of Porites lutea, among Scleractinian corals, seems to be as a good bioindicator in monitoring studies of metal pollution.

Spatio-temporal variability, distribution and sources of n-alkanes and polycyclic aromatic hydrocarbons in reef surface sediments of Kharg and Lark coral reefs, Persian Gulf, Iran.

Environmental pollution, particularly oil pollution, has been a long-standing problem in marine areas. With the aim to assess the pollution status in the Persian Gulf, Iran, herein surface sediments were collected from Kharg and Lark coral reefs, in summer (dry season) and winter (wet season), to evaluate the spatio-temporal variations of n-alkanes and PAHs. The mean total organic carbon (TOC) contents of sediments showed a significantly dramatic variation (p < 0.05) in both seasons at both Islands, with high values recorded at sites located near pollutant inputs. The total mean percent of clay grain-sized sediments at Kharg were 26.57% and 28.86% in dry and wet seasons, respectively, while in Lark were 26.73% in summer and 24.57% in winter. Additionally, at Kharg the mean ∑25n-alkanes and ∑30PAHs ranged from 81.35 to 573 µg g-1 dw and 60.25-491 ng g-1 dw in dry season, and 171-754 µg g-1 dw and 41.61-693 ng g-1 dw in winter, respectively. At Lark, the average ∑25n-alkanes and ∑30PAHs varied from 31.18 to 272 µg g-1 dw and 41.25-196 ng g-1 dw in summer, whilst oscillated from 57.99 to 332 µg g-1 dw and 16.56-487 ng g-1 dw in wet season, respectively. The lowest mean level of the examined pollutants were spanned in offshore sites, while the highest average concentrations indicated that contaminated sediments were at onshore stations at both Islands in both seasons. Significant seasonal variations (p < 0.05) were observed at most sampling sites for all pollutants. Molecular Diagnostic Ratio (MDR) and Principal Component Analysis (PCA) indicated that n-alkanes and PAHs had mostly a petrogenic source. The compositional profile of PAHs showed that 2 and 3-ring PAHs were abundant at both sampling sites. Significant positive correlation (r > 0.76) was observed between ∑25n-alkanes and ∑30PAHs at Kharg and Lark sediments with TOC content, especially for the sites with high total pollutant concentrations. Based on the potential impact and ecological risk of n-alkanes and PAHs in surface sediments, it is, therefore, necessary in future studies to focus on their effects on corals and other marine organisms within this ecosystem.

First report of bioaccumulation and bioconcentration of aliphatic hydrocarbons (AHs) and persistent organic pollutants (PAHs, PCBs and PCNs) and their effects on alcyonacea and scleractinian corals and their endosymbiotic algae from the Persian Gulf, Iran: Inter and intra-species differences.

The coral reefs of the Persian Gulf are the most diverse systems of life in the marine environment of the Middle East. Unfortunately, they are highly threatened by local and global stressors, particularly oil pollutants. This is the first quantitative and qualitative study aimed at assessing the concentration and sources of n-alkanes and POPs (PAHs, PCBs and PCNs) in coral tissues, symbiotic algae (zooxanthellae), reef sediments and seawaters in coral reefs of Lark and Kharg in the Persian Gulf, Iran. This work was conducted on eight species of six genera and three families of hard corals and one family of soft coral. A significant variation in the concentration of ∑30n-alkanes and POPs (∑40PAHs, ∑22PCBs and 20PCNs) was found in the decreasing order: zooxanthellae > coral tissue > skeleton > reef sediment > seawater. The bioaccumulation of these compounds was 2-times higher in ahermatypic than in hermatypic corals, among which significant variations were observed in both sites. In Kharg, Porites lutea had the highest mean concentration of ∑30n-alkanes and ∑40PAHs in soft tissue, whereas the lowest values were in Platygyra daedalea. A contrasting trend was documented for ∑22PCBs and 20PCNs, with the highest level reported in soft tissue of P. daedalea and the lowest in P. lutea at Kharg. Compositional pattern of AHs and PAHs demonstrated the predominance of LMW-PAHs and n-alkanes. In skeleton and reef sediments, tetra, penta and tri-CBs were the most abundant PCBs congeners followed by di-CB > hexa-CB > hepta-CB > octa-CB,whiletri-CB > di-CB > tetra-CB > penta-CB > hexa-CB > hepta-CB > octa-CB was observed for soft tissue, zooxanthellae and seawater. The results of RAD test indicated significantly negative correlation between total concentration of these compounds with zooxanthellae density, the chlorophyll-a and C2 in corals at both reefs. This is the first report on levels, health assessment and source apportionments of POPs in zooxanthellae and a first step in the implementation of specific coral reef management measures.

Spatial distribution, ecological and health risk assessment of heavy metals in marine surface sediments and coastal seawaters of fringing coral reefs of the Persian Gulf, Iran.

Concentrations of 13 heavy metals (Al, Fe, Mn, Zn, Cu, Cr, Co, Ni, V, As, Cd, Hg, Pb) in 360 reef surface sediments (0-5 cm) and coastal seawater samples from ten coral Islands in the Persian Gulf were analyzed to determine their spatial distribution and potential ecological risks. Different sediment quality indices were applied to assess the surface sediment quality. The mean concentrations of metals in studied sediments followed the order: Al > Fe > Ni > V > Mn > Zn > Cu > Cr > Co > As > Cd > Pb > As. Average Cd and Hg exceeded coastal background levels at most sampling sites. With the exception of As, concentrations of heavy metals decreased progressively from the west to the east of the Persian Gulf. Based on the Enrichment Factor (EF) and Potential Ecological Risk Index (RI), concentrations of V, Ni, Hg and Cd indicated moderate contamination and is of some concern. The mean values of heavy metals Toxic Units (TUs) were calculated in the following order: Hg (0.75)> Cr (0.41)> Cd (0.27)> As (0.23)> Cu (0.12)> Zn (0.05)> Pb (0.009). Furthermore, the mean contributing ratios of six heavy metals to Toxic Risk Index (TRI) values were 79% for Hg, 11.48% for Cd, 6.16% for Cr, 3.27% for Cu, 0.07% for Zn and 0.01% for Pb. Calculated values of potential ecological risk factor, revealed that the risk of the heavy metals followed the order Cd > Pb > Ni > Cr > V > Cu > Zn. The results reflected that the level of heavy metals, especially Hg and Cd, are on rise due to emerging oil exploration, industrial development, and oil refineries along the entire Gulf. Fe, Mn, Cu, Zn, V and Ni concentrations in seawater were significantly higher (p < 0.05) than the other detected dissolved heavy metals in the sampling sites. A health risk assessment using the hazard quotient index (HQ) recommended by the USEPA suggests that there is no adverse health effect through dermal exposure, and there is no carcinogenic and non-carcinogenic harm to human health.