Trace and Major Elements Concentration in Fish and Associated Sediment-Seawater, Northern Shores of the Persian Gulf

Elevated trace element concentrations in Arabian scallops, Natal rock oysters, and Intermediate clams in the Persian Gulf

BACKGROUNDS

This study aimed to quantify trace element concentrations in Arabian scallops (Mimachlamys sanguinea), Natal rock oysters (Saccostrea cucullata), and Intermediate clams (Tivela damaoides). These elements accumulate over time from water, food, and sediment, potentially leading to toxicity.

MATERIALS AND METHODS

Specimens were collected from coastal waters around Larak Island, processed, and analyzed for trace elements including copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), zinc (Zn), vanadium (V), magnesium (Mg), manganese (Mn), selenium (Se), nickel (Ni), and cobalt (Co). The samples were ashed, digested, and then analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

The findings revealed that Fe levels were highest in T. damaoides, significantly exceeding those in M. sanguinea (p < 0.05). Cd concentrations were significantly higher in M. sanguinea compared to S. cucullata and T. damaoides (p < 0.05). Zn, Mn, Ni, Pb, V, Co, Hg, Cu, As, and Se showed no significant interspecies differences (p > 0.05). However, significant variations were noted for Mg with T. damaoides showing the highest levels markedly more significant than those observed in M. sanguinea (p < 0.05). Comparison with WHO/FAO standards showed that Pb levels in the soft tissues of all three bivalve species exceeded permissible limits, though other metals were within safe consumption levels.

CONCLUSION

This study revealed that lead concentrations in the soft tissues of bivalves exceeded WHO/FAO safety limits, indicating a potential health risk. These findings emphasize the necessity of monitoring trace element contamination in bivalves to ensure seafood safety and protect public health.

Spatial distribution and the ecological risks posed by heavy metals and total petroleum hydrocarbons (TPHs) in the sediments of mangrove and coral habitats of Northeast Persian Gulf

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.

Risk assessment of heavy metals and total petroleum hydrocarbons (TPHs) in coastal sediments of commercial and industrial areas of Hormozgan province, Iran

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 HNO3, 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.

Lactational Exposure of Human Infants to Metal (loid)s: A Comparison of Industrial and Urban Inhabitants in North of the Persian Gulf

In this study, postnatal metal (loid)s (MLs) exposure was compared between the petrochemical and gas area of Asaluyeh (PGA) and urban area of Kaki (UA) in Bushehr province, Iran. Two hundred human breast milk (BM) samples from the industrial and urban areas were analyzed for MLs using Inductivity Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Boron (B), copper (Cu), iron (Fe), and nickel (Ni) were found at the highest levels in both study areas. Adjusted multiple linear regression models revealed that the mean concentration of total MLs in BM samples collected from the PGA was statistically significantly greater than that of the UA (655.85 vs. 338.17 µg/L). Also, the mean concentrations of all detected MLs in BM samples collected from the PGA were statistically significantly higher than those collected from the UA. The hazard index (HI) of combined MLs in the PGA and UA illustrated non-cancer risk for infants. Lead (Pb) and chromium (Cr) in the PGA and Cr in the UA showed the risk of cancer. So it can be concluded that nursing infants from an industrial area are most at risk for MLs exposure during entire lactation course than those from an urban area.

Potential toxic elements in costal sediment of the Persian Gulf: a systematic review-meta-analysis, non-dietary risk assessment and ecological risk assessment

Potential toxic element (PTE) contamination in the Persian Gulf has become an important health concern in recent decades. This investigation aimed to meta-analyses of potential toxic elements including lead (Pb), inorganic arsenic (As), cadmium (Cd), nickel (Ni), and mercury (Hg) in the coastal sediment of the Persian Gulf. In this study, an attempt was made to retrieve papers conducted on the concentration of PTE in the coastal sediment of the Persian Gulf by searching in international databases including Web of Science, Scopus, Embase, and PubMed. Meta-analysis concentration of PTE in the coastal sediment of the Persian Gulf was conducted using random effects model based on the country subgroup. Additionally, non-dietary risk assessment including non-carcinogenic and carcinogenic risks from ingestion, inhalation and dermal contact routes and ecological risk assessment was estimated. Seventy-eight papers with 81 data-reports (1650 sample size) were included in our meta-analysis. The rank order of heavy metals in coastal sediment of the Persian Gulf based on pooled concentration was Ni (65.44 mg/kg) > Pb (58.35 mg/kg) > As (23.78 mg/kg) > Cd (1.75 mg/kg) > Hg (0.77 mg/kg). The highest concentration of As, Cd, Pb, Ni, and Hg was observed in the coastal sediment of Saudi Arabia, Arab Emirates, Qatar, Iran, and Saudi Arabia, respectively. Although the I_geo index in coastal sediment of the Persian Gulf was in grade 1 (uncontaminated) and grade 2 (slightly contaminated) but total target hazard quotient (TTHQ) of adults and adolescent was higher than 1 value in Iran, Saudi Arabic, United Arab Emirates, and Qatar. Total cancer risk (TCR) for adults and adolescent due to As was higher than 1E-6 in Iran, United Arab Emirates, and Qatar but TCR for adolescents due to As was higher than 1E-6 in Saudi Arabic. Therefore, it is recommended to monitor the concentration of PTE and implementation of programs to reduce the emission of PTE from resources in the Persian Gulf.

Using empirical negative cumulative extropy and image quality assessment to determine the accumulation of elements in marine organisms

In this study, the assessment of metals absorption capacity by macroalgae using image analysis was investigated for the first time and compared with fish bioaccumulatio. Empirical cumulative entropy (ECE), and also empirical negative cumulative extropy (ENCEX) were used as a newly introduced (information-based) indices. The regression equation was obtained between fish tissue-seawater in muscle of Sphyraena putnamiae (ENCEX=0.2001BAF; R²=0.96); In the case of muscle of Liza subviridis, the regression model was as (ENCEX=0.1950BAF; R²=0.93). The regression equation was obtained between algae-sediment (ENCEX_{H. hamulosa}=0.2695BAF; R²=0.97). The studied indices showed a high accumulation of Hypnea hamulosa compared to the other algae (ECE=0.2601; ENCEX=0.3995). IQA method showed the same result exhibiting that the algae can be evaluated as a bio-indicator of element accumulation using image analysis. Image analysis can help us find macro algae with high absorption capacity without laboratory examinations.

Metals bioaccumulation, possible sources and consumption risk assessment in five Sillaginid species, a case study: Bandar Abbas (Persian Gulf) and Chabahar Bay (Oman Sea), Iran

In this study, the concentrations of 10 metals (As, Al, Cd, Cr, Cu, Fe, Hg, Ni, Pb and Zn) in different tissues (gill, muscle and otolith) of five sillaginid species (Sillago arabica, S. attenuata and S. sihama from the Persian Gulf and S. indica, S. sihama and Sillaginopodys chondropus from the Oman Sea) were analyzed using ICP-MS, and the potential human health risk assessment for local consumers was also conducted using standard indices. The concentration of trace metals (μg g^-1 dw) in fish ranged from 0.24 to 16.09 (As), 7.88 to 167.51 (Al), 0.005 > -0.866 (Cd), 0.006 > -7.95 (Cr), 1.02-5.58 (Cu), 24.86 to 390.85 (Fe), 0.005 > -1.93 (Hg), 0.021 > -7.80 (Ni), 0.33-4.41 (Pb) and 4.78-170.43 (Zn). The levels of trace metals varied significantly among sampling sites, fish species and their tissues. Gill tissues accumulate higher concentrations of the analyzed elements, except for As and Hg, whose higher concentrations were found in muscle tissues. Among the species, S. sihama in the Persian Gulf showed the highest levels of toxic metals compared to the other species. The dendrogram of metal association in fish muscle tissues revealed that Ni, Cr, Cd, Pb and Hg in muscles mainly originated from anthropogenic sources, especially petroleum activities. A second dendrogram based on the association of these five metals in the muscle tissue separated the sillaginid species of the Persian Gulf from the Oman Sea. The mean concentrations of the analyzed metals in the edible tissues were lower than international standards of maximum permissible limits (MPL), except for inorganic As (_iAs) and Pb. The index of estimated daily intake (EDI) for Cr and Hg in all sillaginid species, and _iAs, Pb and Ni only in the Persian Gulf's sillaginid species was higher than the recommended values. The value of the target hazard quotient (THQ) indicated that the intake of individual heavy metals due to the consumption of sillaginid species was safe for human health (except Hg in S. arabica) whereas combined heavy metals' intake revealed potential health problems in the case of increased consumption for all three sillaginids in the Persian Gulf. Target cancer risk (TR) for _iAs in all species and Cd, Cr and Ni in Persian Gulf species was higher than the acceptable range. The results indicated the health issues associated with high consumption, especially for sillaginids in the Persian Gulf, which should be considered in food safety monitoring for local people in the area.

Pollution zoning on the southern shores of the Caspian Sea by measuring metals in Rutilus kutum tissue

The aim of this study was to bio monitor the status of heavy metals on the southern shores of the Caspian Sea by determining the concentration of these metals in the tissue of Rutilus kutum. Sampling of kidney tissue, liver, muscle, skin, and gonad of this fish was performed in 5 sites. Sampling was performed in Anzali, Kiashahr, Astara, Farahabad, and Bandar Torkaman from September 2017 to January 2018. In this study, the concentration of elements in different tissues was determined. Contamination zonation was determined by the concentration of metals in fish tissues. The highest amount of Pb accumulation (0.73 ppb) was determined in Astara and Anzali regions and in liver tissue. The highest amount of Cd (0.23 ppb) was reported in Astara region and in fish liver. Zoning showed that the concentration of most elements in the west of the Caspian Sea is higher than in the east; in other words, the west of the Caspian Sea is more polluted than the east. Existence of polluting sources such as ports, customs, agricultural lands, and tourism industry are important factors of pollution in these areas. Annual biological monitoring along with accurate identification of pollutant sources can help reduce this pollution, especially in the western part of the Caspian Sea. This study showed that the use of zoning technique in environmental studies as an effective management tool can be very useful in providing appropriate ways to identify and control sources and pollutants in the coast.

Health risk assessment of commercial fish and shrimp from the North Persian Gulf

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.

Food safety of the green tiger shrimp Penaeus semisulcatus from the Persian Gulf

Seafood is a rich source of essential compounds for human health, but the consumption of aquatic products that are exposed to environmental pollutants, especially trace metals, comes with risk. Therefore, in this study, the levels of nickel, zinc, and lead in the muscle of shrimp Penaeus semisulcatus caught from the north of the Persian Gulf as a polluted environment were measured, and the health risks were assessed. The results showed that the level of Zn (300.88 ± 2.76 µg/g) in the muscle of shrimp was higher than Ni (6.82 ± 0.10) and Pb (1.10 ± 0.09 µg/g), and the amount of accumulation of all three metals is higher than the allowable limit proposed by the FAO/WHO. According to values of estimated daily intake (EDI) and target hazard quotient (THQ), the consumption of shrimp has no or minimal risk for health. However, the target cancer risk (TR) of Ni (adult, 0.00294; child, 0.00196) indicated that Ni accumulation is associated with carcinogenic risks. These findings may be helpful in the proper management of seafood quality and public health in the Persian Gulf.

A systematic review of the concentration of potentially toxic elements in fish from the Persian Gulf: A health risk assessment study

Fish as a critical food source is responsible for supplying nearly 20% of the average per capita animal protein for 3.2 billion people worldwide. However, oral exposure to potentially toxic elements (PTE) such as mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) through marine fish consumption can cause health risks in consumers. This study aimed to collect information among databases (2000-2020), including ScienceDirect, PubMed, SCOPUS, EMBASE, and Google Scholar, regarding the concentration of PTEs in different types of fish from the Persian Gulf. In this regard, thirty articles containing 266 samples were included in the current systematic review. In addition, the non-carcinogenic risk caused by ingestion of PTEs via consumption of fish was calculated. The average PTE concentrations in fish muscles were presented in the following order: As (0.37 mg/kg ww) > Pb (0.20 mg/kg ww) > Cd (0.17 mg/kg ww) > Hg (0.13 mg/kg ww). However, the mean concentration of PTEs was below the defined level by the World Health Organization, and the findings revealed that the calculated average daily dose (ADD) for Cd and Pb in Iranian children and adult consumers was lower than the reference dose (RfD), whereas the ADD of Hg was higher than the RfD for children consumers. The total target hazard quotient for Iranian and children consumers was >1. The excess lifetime cancer risk values for Pb were safe, unlike those for Cd, which were in an unsafe range (>10^-4) for consumers.

Predicting the Trace Element Levels in Caspian Kutum (Rutilus kutum) from South of the Caspian Sea Based on Locality, Season and Fish Tissue

Elements are the shared result of the erosion of rocks in the catchment area and human activities. Nutritional habits, ecological needs, heavy metal concentrations in water and sediment, duration of fishing in the aquatic environment, fishing season, and physicochemical properties of water (salinity, pH, hardness, and temperature) are among the effective factors in the accumulation of heavy metals in various fish organs. In this study, 150 specimens of Rutilus kutum were collected from the southern shores of the Caspian Sea including Astara, Anzali, and Kiashahr in Guilan Province, Farahabad in Mazandaran Province, and Bandar Torkaman in Golestan Province from December 2018 through October 2019. It is possible to predict the metal concentrations using the variables such as fish tissue, sampling region, and season. Akaike information criterion (AIC) was used to select the best regression model. We used fish muscle tissue and Anzali sampling site which were considered reference variables in the regression model. For some elements, a better model is obtained by considering all variables (AIC criterion is its lowest value). The best model obtained for Cu, Mn, and Si was only with region (as a variable). The best model obtained for Sn and Sr only concerns the region and tissue variables. The best model obtained for Sb only related to tissue variable. Using these models, environmental monitoring becomes easier and cheaper. We suggest further studies to be carried out in the shortest possible time along with the least laboratory cost.

Metals in tissues of marine fish from the Thermaikos Gulf, Eastern Mediterranean Sea: Detection of changes with trophic level

Concentrations of 27 metals and elements were investigated in the tissues of 28 demersal and pelagic marine fish species from the Eastern Mediterranean Sea. The analysis indicated highest concentrations of accumulation for the majority of elements in the gills, liver, and scales; whereas, lowest assimilation of elements was reported in the muscle. Pelagic fish accumulated higher concentrations of elements than demersal fish. An inverse correlation due to the growth dilution effect was revealed among element concentrations in the gills, liver, muscle, and skin tissues, and fish size. Patterns of biomagnification for Cs solely were recorded in the muscle and patterns of biodilution for most elements were evident in the gills, liver, muscle, and skin tissues. A positive correlation was determined between trophic level and element concentrations in the scales which could not only be associated with fish diet, but also with metal concentrations in the ambient environment and scales size.

Bioaccumulation of heavy metals in fish species of Iran: a review

Accumulation of heavy metals (HMs) in fish tissues is an important factor in monitoring the health and safety of aquatic ecosystems. Furthermore, fish are important parts of aquatic food chains and play a significant role in human health. Considering the significant role of fish in the diet of humans and their ability to transfer and biomagnify HMs, it is necessary to determine and study these contaminants in fish tissues, especially in the edible parts of the fish. In addition to the other ecological and economic services of aquatic ecosystems, water bodies, especially the Persian Gulf in the south and the Caspian Sea in the north of Iran, are the main sources of seafood for people in nearby areas, as well as people living farther away who have gained access to seafood due to the extensive trade of aquatic organisms. This study provides an overview of the health conditions of the aquatic ecosystems in Iran by monitoring HM bioaccumulation in fish species. For this purpose, we reviewed, summarized, and evaluated papers published on HM concentrations in fish species from different aquatic ecosystems, including the Persian Gulf, the Caspian Sea, wetlands, rivers, qanats, water reservoirs, lakes, and dams, with emphasis on species habitats, feeding habits, and target organs in accumulation of HMs. Generally, the highest concentrations of HMs were observed in fishes collected from the Persian Gulf, followed by species from the Caspian Sea. Species inhabiting the lower zone of the water column and carnivorous and/or omnivorous species showed the highest levels of HMs. Moreover, liver was the main accumulator organ for HMs.