Mercury accumulation in selected tissues of shrimp Penaeus merguiensis from Musa estuary, Persian Gulf: variations related to sex, size, and season

Heavy metal concentration according to shrimp species and organ specificity: Monitoring and human risk assessment

This study assessed heavy metal levels (lead (Pb), cadmium (Cd), total arsenic (tAs), arsenite (As (III)), arsenate (As (V)), monomethyl arsenic acid (MMA), dimethylarsinic acid (DMA), total mercury (tHg), and methylmercury (MeHg)) in six organs (total portion, head, body, shell, muscle, and intestine) of 11 shrimp species distributed in Korea. Shrimp exhibited significant variability in heavy metal accumulation, with Alaskan pink and dried shrimp (Lesser glass, Southern rough, and Chinese ditch prawn) showing the highest metal concentrations. Notably, the intestine having the highest overall metal content, while Cd was most prominent in the head, tHg was highest in the muscle. The Hazard Quotient values of 11 shrimp species in South Korea were below the European Food Safety Authority's allowable limits for heavy metals. This study illuminates the heavy metal profiles of distributed shrimp in Korea and emphasizes the ongoing need for monitoring heavy metals on seafood to ensure consumer safety.

A Systematic Review on Metal Dynamics and Marine Toxicity Risk Assessment Using Crustaceans as Bioindicators

Metals, many of which are potentially toxic, are present in the aquatic environment originated from both natural and anthropogenic sources. In these ecosystems, these elements are mostly deposited in the sediment, followed by water dissolution, potentially contaminating resident biota. Among several aquatic animals, crustaceans are considered excellent bioindicators, as they live in close contact with contaminated sediment. The accumulation of metal, whether they are classified as essential, when in excessive quantities or nonessential, not only cause damage to the health of these animals, but also to the man who consumes seafood. Among the main toxic elements to animal and human health are aluminum, arsenic, cadmium, chromium, copper, lead, mercury, nickel and silver. In this context, this systematic review aimed to investigate the dynamics of these metals in water, the main bioaccumulative tissues in crustaceans, the effects of these contaminants on animal and human health, and the regulatory limits for these metals worldwide. A total of 91 articles were selected for this review, and an additional 68 articles not found in the three assessed databases were considered essential and included, totaling 159 articles published between 2010 and 2020. Our results indicate that both chemical speciation and abiotic factors such as pH, oxygen and salinity in aquatic environments affect element bioavailability, dynamics, and toxicity. Among crustaceans, crabs are considered the main bioindicator biological system, with the hepatopancreas appearing as the main bioaccumulator organ. Studies indicate that exposure to these elements may result in nervous, respiratory, and reproductive system effects in both animals and humans. Finally, many studies indicate that the concentrations of these elements in crustaceans intended for human consumption exceed limits established by international organizations, both with regard to seafood metal contents and well as daily, weekly, or monthly intake limits set for humans, indicating consumer health risks.

Tracing the heavy metals zinc, lead and nickel in banana shrimp (Penaeus merguiensis) from the Persian Gulf and human health risk assessment

Seafood has long been considered a unique source of nutrition. However, increasing trends in consumption of marine products must be considered, especially in potentially polluted environments such as the Persian Gulf. This study was undertaken to analyse the level of heavy metal contamination of nickel (Ni), zinc (Zn), and lead (Pb) in shrimp (Penaeus merguiensis) captured from the northern Persian Gulf. The concentration of heavy metals in the muscle of shrimp followed the order Zn > Ni > Pb. The content of Zn and Ni was higher than recommended standard limits by the FAO/WHO. The combined impact of all metals was lower than the acceptable limit of 1 in shrimp. The carcinogenic risk for Ni was higher than the unacceptable value. In total, our finding indicated no potential health risk from the daily consumption of this species. However, long-term consumption of shrimp can pose a risk of carcinogenic effects of nickel. Continuous monitoring of these trace metals in seafood is necessary to ensure the quality of seafood and food safety.

In vivo visualization assay to evaluate the effects of maternal exposure to mercury on offspring bioaccumulation in the oriental river prawn (Macrobrachium nipponense)

Mercury (Hg) is a persistent pollutant that accumulates in aquatic animals. However, studies related to understand how gonad tissue of this species responds to mercury exposure and elucidation of mercury bioaccumulation in crustacean offspring by cross-generational, are still sparse. The present study aimed to assess the bioaccumulation of Hg²⁺in vivo in prawn offspring by a specific aggregation-induced emission fluorogen (AIEgen). The 96 h median lethal concentration (LC₅₀) values of mercury to the juveniles were 0.072 mg/L. Hg²⁺ reduced growth performance, damaged oocyte quality, and inhibited ovary maturation, thus inhibiting gonadal maturation in intact prawns. F1 offspring were exposed to Hg²⁺ by direct transfer from their F0 parents, as shown by the distribution of mercury in gonads and fertilized eggs. In the medium containing oriental river prawn larvae, the Hg²⁺ concentration decreased rapidly, indicating fast initial larval uptake of Hg²⁺. Due to metal ion triggered AIE activity, analysis of fluorescence images showed that prawn offspring accumulated Hg²⁺ via maternal transfer, and there was a relationship among the photoluminescence intensity, the AIEgen concentration, and mercury levels. The quantitative detection of Hg²⁺ absorption from prawn larvae by the AIEgen represents a novel analytical technique to understand the dynamics of Hg²⁺ between maternal and offspring.

Cadmium-induced oxidative stress, metabolic dysfunction and metal bioaccumulation in adult palaemonid shrimp Palaemon macrodactylus (Rathbun, 1902)

The Palaemonid shrimp Palaemon macrodactylus is widely distributed in coastal areas and estuaries which are easily contaminated by various pollutants. However, the responses of this species to environmental toxicants are not well described. In the present study, adult individuals of P. macrodactylus were exposed to gradient concentrations of Cadmium (Cd) to evaluate its acute toxic effects, including bioaccumulation, induced oxidative stress and changed energy metabolism in this species. The medium lethal concentration (LC₅₀) of Cd at 24 h, 48 h, 72 h, and 96 h were 2.60, 0.88, 0.49 and 0.37 mg/L, respectively. Cd bioaccumulations in tissues of shrimp increased in a concentration-dependent manner, and higher concentration (50% 96 h-LC₅₀, 0.185 mg/L) of Cd exposure led to a maximum increase of Cd concentration by 14.8, 145.5 and 15.8 folds in gill, hepatopancreas and abdominal muscle. Cd exposure caused a significant inhibition on the activity of catalase (CAT), and total superoxide dismutase (T-SOD), decrease in the total antioxidant capacity (T-AOC), and an increase of malonadehyde (MDA) content, which indicated a damage to the antioxidant system of shrimp. Meanwhile, Cd exposure also led to a significant up-regulation in the expression level of metallothionein gene (MT), and down-regulations at the mRNA level of heat shock protein 70 (HSP70) and CAT. Moreover, Cd exposure significantly inhibited the oxygen consumption rate (22%), and increased the ammonia excretion rate (43%), hence lead to a significant decrease of the O:N ratio (45%) in shrimp. The results indicated that Cd exposure could induce obvious oxidative stress, energy metabolic dysfunction and bioaccumulation of Cd in P. macrodactylus. The data obtained from the present study would provide useful information for further understanding on the toxicological mechanism of Cd to crustaceans in coastal areas and estuaries.

Studying absorbance properties and mercury remediation capabilities of gold-graphene oxide-iron oxide (Au-GO-Fe3O4) nanoparticle systems

Mercury pollution is a rampant problem in many economically significant Philippine freshwater ecosystems. Communities dependent on these freshwater sources are therefore at risk for exposure to harmful levels of mercury. Various formulations of a novel gold-graphene oxide-iron oxide (Au-GO-Fe₃O₄) hybrid nanoparticle system were created and subjected to UV-Vis spectroscopy to determine optimal formulations that would best serve as potential substrates for Surface-Enhanced Raman Spectroscopy (SERS) detection of mercury. Optimal formulations of Au-GO-Fe₃O₄ were also introduced into mercury-polluted environments to evaluate its ability to remove mercury from both water and biological tissues. Spectroscopic analysis revealed that Fe₃O₄-rich formulations of Au-GO-Fe₃O₄ had the greatest potential to boost Raman signal intensities of mercury due to red shifting of absorbance peaks and overall increased absorbance across visible wavelengths resulting in the inclusion of greater areas underneath absorbance peaks. Mercury remediation experiments likewise demonstrated Au-GO-Fe₃O₄ to significantly reduce average concentrations of mercury from 1.67 to 0.82 ppm in polluted water samples - corresponding to a mercury removal efficiency of 50.9% and a mercury adsorption capacity of 5.89 mg/g. The results highlight the viability of Au-GO-Fe₃O₄ to function as both substrate for SERS detection of mercury and as effective adsorbent for mercury remediation.

Assessing Human Health Risks Associated with Consumption of Metal Content in Shrimp from NW Mexico

Shrimp of Farfantepenaeus californiensis (78 groups) and Litopenaeus stylirostris (14 groups) were caught in the northwestern fishing zones in Mexico during the 2014-2015 fishing season (September-February); both shrimp species have high commercial value. Muscle, hepatopancreas and exoskeleton were analyzed to determine their metal contents. For F. californiensis, the highest Cd, Pb and Zn contents were determined in specimens caught off the State of Baja California Sur (BCS) with 22.4 ± 8.9 (hepatopancreas), 2.83 ± 4.63 (muscle), and 748.5 ± 1567 (muscle) µg/g, in the regions off Mulegé, Los Cabos and Los Cabos, respectively. For L. stylirostris, the fishing zone of Comundú (BCS) showed higher Cd (12.3 ± 11.5 µg/g), Cu (569.1 ± 646.5 µg/g) and Zn (549.7 ± 400.7 µg/g) contents; all values were determined in the hepatopancreas. Regarding the hazard quotient and total hazard quotient calculated in this study, the consumption of marine shrimp caught off NW Mexico does not represent a risk to human health (both < 1).

The comparison of selenium and lead accumulation between contaminated muddy and sandy sediments from four estuaries along the Persian Gulf: effect of grain size

Persian Gulf is one of the most important water sources in the economically developed south part of Iran, and metal pollution is a major concern for the Gulf. The bioavailability and distribution of selenium (Se) and lead (Pb) between muddy and sandy sediments from four estuaries along the Persian Gulf were analyzed. The geoaccumulation index and enrichment factor for metals and correlation between particles size with metals concentration were studied. The average concentration of metals in sediment was ranged 0.08-1.14 µg/g for Se and 0.32-4.37 µg/g for Pb in all estuaries, with the highest concentrations in Musa estuary. The results showed there was positive correlation between particles size of sediment with metals concentration. The highest of metal concentration was absorbed in silt (< 63 μm) sediment, followed by extremely fine sand (63-125 μm), fine sand (125-250 μm), medium sand (250-500 μm) and coarse sand (500-1000 μm), respectively. The organic matter and carbonate in the muddy sediment are higher than sandy sediment, and they had high specific storage capacity for accumulation of heavy metals. The result of Pearson correlation (r) for organic matter and metal was 0.78 for Se and 0.67 for Pb, and for carbonates and metal was 0.54 for Se and 0.61 for Pb. The values of EF in all estuaries show that the enrichment of sediment by heavy metals was by anthropogenic activities such as discharge of petrochemical and oil industrial. Geoaccumulation index indicates that the sediment in the Ahmadi and Ghanam estuaries was unpolluted to moderately polluted, while in the Arvand river is moderately to strongly polluted, and in the Musa estuary is extremely polluted.

Acute toxic effects of zinc and mercury on survival, standard metabolism, and metal accumulation in juvenile ridgetail white prawn, Exopalaemon carinicauda

Ridgetail white prawn (Exopalaemon carinicauda) is widely distributed in Chinese coastal zones, especially in the Yellow Sea and Bohai Sea. It is not only considered as an important economic species in China, but also taken as a potential indicator species for the environmental pollution in the estuaries. At present, the responses of this species to environmental toxicants, including trace metal are not well understood. In this study, the acute toxic effects of zinc (Zn) and mercury (Hg) on the survival, oxygen consumption, ammonia-N excretion, and metal accumulation were investigated in the juveniles of E. carinicauda. The median lethal concentrations (LC₅₀) of Zn were 76.4, 44.0, 30.2, and 17.2mg/L, respectively, after the juveniles were exposed in for 24, 48, 72, and 96h, and the LC₅₀ of H_g was 0.212, 0.096, 0.084, and 0.065mg/L under the same exposure duration. The juveniles decreased the oxygen consumption by 51.4%, and increased ammonia-N excretion by 129% when they were exposed in Zn at the concentration of 76.4mg/L compared with their controls without Zn exposure, therefore the O:N ratio decreased by 82.9% compared with the control. Hg exposure with the concentration of 0.212mg/L caused the inhibition of oxygen consumption by 48.1% and increasement of ammonia-N excretion by 161%, and the atomic ratio of consumed oxygen to excreted ammonia-nitrogen (O:N ratio) decreased by 80.6% in the juveniles in comparison with the control. A concentration-dependent accumulation of heavy metals was observed in the gills, hepatopancreas and muscles of the experimental animals, with a maximum accumulation of 16.3 folds for Zn and 72.8 fold for Hg in the gills of the juveniles after 24h exposure. The data obtained from the present study would provide useful information for help further understanding on the toxicological responses of this species to trace metals.

Geochemistry and mercury contamination in receiving environments of artisanal mining wastes and identified concerns for food safety

Artisanal small-scale gold mining (ASGM) using mercury (Hg) amalgamation has been occurring on Buru Island, Indonesia since early 2012, and has caused rapid accumulation of high Hg concentrations in river, estuary and marine sediments. In this study, sediment samples were collected from several sites downstream of the Mount Botak ASGM site, as well as in the vicinity of the more recently established site at Gogrea where no sampling had previously been completed. All sediment samples had total Hg (THg) concentrations exceeding Indonesian sediment quality guidelines and were up to 82 times this limit at one estuary site. The geochemistry of sediments in receiving environments indicates the potential for Hg-methylation to form highly bioavailable Hg species. To assess the current contamination threat from consumption of local seafood, samples of fish, molluscs and crustaceans were collected from the Namlea fish market and analysed for THg concentrations. The majority of edible tissue samples had elevated THg concentrations, which raises concerns for food safety. This study shows that river, estuary and marine ecosystems downstream of ASGM operations on Buru Island are exposed to dangerously high Hg concentrations, which are impacting aquatic food chains, and fisheries resources. Considering the high dietary dependence on marine protein in the associated community and across the Mollucas Province, and the short time period since ASGM operations commenced in this region, the results warrant urgent further investigation, risk mitigation, and community education.

Mercury and selenium concentrations in marine shrimps of NW Mexico: health risk assessment

We determined total Hg and Se contents of hepatopancreas, exoskeleton, and muscle, and the Se:Hg molar ratios in the muscle of shrimps Farfantepenaeus californiensis and Litopenaeus stylirostris caught in NE Pacific Mexican waters. Total Hg mean values in muscle, hepatopancreas, and exoskeleton were 0.31 ± 0.26, 0.28 ± 0.29, and 0.24 ± 0.06 μg g^-1, and 0.46 ± 0.46, 0.41 ± .034, and 0.24 ± 0.06 μg g^-1 for F. californiensis and L. stylirostris, respectively. In all tissues, the mean concentrations of Se tended to be close to one order of magnitude higher than the respective Hg values. In F. californiensis, the hepatopancreas of the larger commercial size had significantly (p < 0.05) higher Hg content than smaller sizes, but correlations size-Hg concentration calculated for each tissue of either species were not significant. The Hg content of the muscle of all commercial sizes of both species was lower than the permissible limit and their Se:Hg ratios in all sizes were higher than 1, indicating low risk for human consumption.

Bioaccumulation of polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbon (PAH), mercury, methyl mercury, and arsenic in blue crab Portunus segnis from Persian Gulf

Bioaccumulation of polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbon (PAH), mercury (Hg), methyl mercury (MMHg), and arsenic (As) in the hepatopancreas and muscle of blue swimming crab Portunus segnis from Bushehr shore, north Part of Persian Gulf, were investigated. In addition, the relationships between crab size (carapace width) and PCBs, PAH, Hg, MMHg, and As levels in tissues were investigated by linear regression analysis. There were significant correlation between pollutants levels and crab size which were positive. The pollutants' concentrations were highest in hepatopancreas whereas lowest in the muscle of all crab species. The mean concentrations were 0.51 ng g(-1)PCB 16, 0.64 ng g(-1) PCB 99, 1.2 μg g(-1) Hg, 0.81 μg g(-1) MMHg, and 0.14 μg g(-1) As. Also, mean concentrations of different PAHs were 0.31 ng g(-1) Acenaphthylene, 0.51 ng g(-1) Acenaphthene, and 0.71 ng g(-1) Anthracene. Comparison between male and female indicated that the average PCBs, PAH, Hg, MMHg, and As concentrations in tissues of male crab were found to be significantly higher than those found in the female crab.