Mercury concentrations in seafood and the associated risk in women with high fish consumption from coastal villages of Sonora, Mexico

Distribution and health risk assessment of heavy metals in the octopus (Octopus hubbsorum) in the Mexican Pacific

Heavy metal (HM) concentrations in coastal marine species and the health risks (HR) for the consumption of these resources remain relatively unknown. We determined the concentrations of Cd, Cu, Hg, Pb, and Zn in the arm and mantle tissues of 150 Octopus hubbsorum specimens collected from seven sites in the Mexican Pacific in 2021. Samples were processed by microwave-assisted acid digestion, and concentrations were determined by anodic stripping voltammetry. The HR for adults and children exposed to HM through the consumption of O. hubbsorum was determined by the hazard quotient (HQ) and risk index (HI). Five HM were found in all samples. The concentrations followed the order of Zn > Cu > Cd > Pb > Hg, with most sites exhibiting Cd and Pb concentrations above the maximum permissible limit (MPL) established by national and international standards. However, the values of HQ and HI did not exceed one (<1) for any heavy metal, indicating that there is no HR due to consuming octopus. Nonetheless, O. hubbsorum exhibited concentrations of some HM above the MPL; therefore, caution should be taken when consuming this species considering the additive and/or potentiation effect that could occur, especially in coastal communities where consumption is higher.

Dietary mercury exposure through fish consumption in a coastal community in northwestern Mexico: a comparison of toxicokinetic models

Mercury (Hg) is a highly toxic heavy metal that presents a notable and worldwide threat to human health and the environment. The most direct method to evaluate the potential effects on human health due to Hg exposure is to monitor biological samples. When biological samples are limited, predictive models are valuable tools to estimate levels of Hg exposure. In this study, fish consumption data was used to compare two toxicokinetic models to predict Hg exposure in a coastal population in northwestern Mexico. To calculate daily Hg intake, 15 children, 42 women, and 18 men were surveyed regarding their fish consumption habits. The data were analyzed using deterministic and probabilistic models, and the results were validated by comparing them with the Hg levels in their hair. Fish consumption varied from 46 to 219 g·day-1. Notably, 6.7% of participants exhibited Hg levels that exceeded the oral reference dose (RfD) of 0.1 μg·kg-1 bw·day-1 and were thus considered to be at risk of adverse health effects. The average Hg concentration in hair among the sampled groups ranged from 1.59 to 4.42 μg·g-1 (with two outlier values of 16.96 and 54.07 μg·g-1). The Hg levels in 86.85% of the population surpassed the reference value of 1 μg·g-1. The predictions generated by the deterministic and probabilistic models based on the ingestion rate (CRj) closely mirrored the actual Hg levels in hair. We highlight the importance of mathematical models to predict the body burden of Hg, particularly when sampling resources are limited.

Human health risks assessment of the fluctuations in mercury levels in seafood from different key regions of Rio de Janeiro, Brazil

Mercury (Hg) contamination on the Brazilian southeast coast has been highlighted, especially in relation to species of commercial importance. This study aimed to quantify the Hg concentration in species of mussels, fish, and crabs obtained from fishing colonies on the beaches of the west and south of the city of Rio de Janeiro, investigate the possible effect of seasonality, sex, and location sampling, and finally, the risk to consumer health in four different age groups. The difference between cooked and raw commercially available mussel samples was also verified. The main results highlight that the fish presented higher levels of Hg and that the mussel samples sold cooked presented lower levels of Hg when compared to the raw ones. For Micropogonias furnieri, Sardinella brasiliensis, and Callinectes spp., the season variable influenced Hg concentrations, while only for Merluccius merluccius was a difference between the sexes identified, with males having the highest values. Although Hg concentrations in animals were below the permitted limit, consumption of all species exceeded the monthly intake limit for this metal. For the hazard quotient (HQ) calculation, most species presented HQ > 1, especially when ingested by the child population. These results are fundamental for designing consumption strategies for these animals, in order to prioritize the acquisition of some species over others, depending on the location and/or season, for each age group, with the aim of maintaining seafood consumption with minimal risk to the population's health.

Mercury contamination in seafood from an aquatic environment impacted by anthropic activity: seasonality and human health risk

Petroleum activity and the dumping of domestic and industrial sewage are important sources of mercury (Hg) contamination in the aquatic environment. Thus, this article aimed to biomonitor the Hg concentration in fish, mussels, and swimming crabs of commercial importance in southeastern Brazil. The quantifications were carried out over a year to verify the influence of seasonality. Finally, a risk assessment was applied to identify whether the concentrations found could lead to long-term damage to the population. Our results indicate that the contaminations were higher in spring, summer, and winter than in autumn, mainly among fish and swimming crabs. The results of quantification in the animal and estimated monthly intake, despite being below the limit established nationally and internationally, were indicative of risk for these two animals after calculating the Hazard quotient. The highest risk values were attributed to the infant population. Based on the data generated by this work, the consumption of mussels is encouraged throughout the year, to the detriment of the other types of seafood studied, especially during summer, spring, and winter. Our work reinforces the importance of risk assessment for a more reliable understanding of the impact of contaminants in seafood on the population's health.

Human health risk assessment of metals and arsenic via consumption of commercial bivalves in the Gulf of California, Mexico

Although various studies have reported the bioaccumulation of metals in bivalves of commercial interest from the Gulf of California (GC), the risk associated with their consumption remains poorly understood. In this study, our own and bibliographic concentrations of 14 elements in 16 species of bivalves from 23 locations were used to investigate (1) the species-specific and regional accumulation of metals and arsenic in bivalves, (2) the human health risks by age and sex, and (3) the maximum allowable consumption rates (CRlim). The assessments were done according to the US Environmental Protection Agency guidelines. The results indicate that the bioaccumulation of elements varies markedly between groups (oysters > mussels > clams) and localities (higher on Sinaloa due to intense anthropogenic activities). However, consuming bivalves from the GC remains safe for human health. To prevent health effects for residents or consumers on the GC, we recommend (1) following the CRlim proposed herein; (2) monitoring levels of Cd, Pb, and As (inorganic) in bivalves, as the elements of top concern, mainly when are consumed by children; (3) calculating CRlim for more species and locations, including at least: As, Al, Cd, Cu, Fe, Mn, Pb, and Zn; and (4) determine the regional consumption rates of bivalves.

Toxic metal and metalloid contamination in seafood from an eutrophic Brazilian estuary and associated public health risks

Guanabara Bay (GB) is a highly contaminated estuarine system and an important fishing area in Southeastern Brazil. In this regard, knowledge concerning the association of certain contaminants in seafood to abiotic factors and human health risk assessments is still understudied. Therefore, this study aimed to quantify nine toxic elements in highly consumed crabs, shrimp, and squid, and associate the results with abiotic factors. A human health risk assessment was also performed. Our findings indicate that crabs are the main bioaccumulators. Transparency and depth were noteworthy for all three taxonomic groups. In general, contaminant concentrations were below the limits established by different international agencies, except for As, which was higher than the Brazilian limit (1 mg kg^-1). However, the Hazard Index identified risks to consumer health for the ingestion of seafood. This study emphasizes the importance of jointly evaluating different toxic elements, for a more accurate health risk assessment.

Organotin contamination in seafood from the Yucatán Peninsula, Mexico: Is there a potential risk for the health of consumers?

Since seafood is considered an important source of organotin compounds (OTCs), the present study assessed the potential risk to human health of ingesting butyltins (BTs) and phenyltins (PhTs) along with this type of food. Seafood samples were collected at five fishing sites in the Yucatán Peninsula (Mexico) during February and March 2018. In general, organotins were detected in all samples, suggesting a widespread occurrence of these compounds in the investigated region. The average concentration of total organotins in the muscle of demersal fish (Lutjanus synagris, Lutjanus campechanus, Calamus pennatula, Haemulon plumierii, Rhomboplites aurorubens), pelagic fish (Euthynnus alletteratus, and Opisthonema oglinum), gastropods (Melongena bispinosa and Strombus pugilis), oyster (Crassostrea virginica) and shrimp (Penaeus duorarum) was 146.7 ± 76.2, 93.1 ± 92.6, 61.0 ± 53.0, 76.7 ± 2.6, and 28.8 ± 2.7 ng Sn g-1 dry weight, respectively. Overall, MPhT among PhTs was the dominant compound in fish, while TBT among BTs was the dominant compound in shellfish. Regarding the toxic OTCs, TBT followed by DBT were the predominant compounds in all seafood species, while TPhT was below the quantification limit in most samples. The estimated daily intake values were lower than the tolerable daily intake (TDI) for the sum of organotins established by the European Food Safety Authority (EFSA). Furthermore, the hazard quotients (HQ) and hazard indices (HI) values were all lower than 1, suggesting that daily exposure to these levels of organotins is unlikely to cause any harm to the human health of seafood consumers at the Yucatán Peninsula. Thus, consumers may not be at risk through the inclusion of these investigated seafood species in their normal diet. However, due to the increasing coastal urbanization, maritime activities, and the likely illegal use of tin-based paints in Mexico, additional monitoring is needed to assess organotin levels in other regions along the Mexican coastal zone and using other seafood species.

Baseline titanium levels of three highly consumed invertebrates from an eutrophic estuary in southeastern Brazil

Titanium (Ti) is considered a contaminant of emerging interest, as it displays toxic potential and has been increasingly employed in everyday products, pharmaceuticals, and food additives, mainly in nanoparticle form. However, several knowledge gaps are still noted, especially concerning its dynamics in the water. In this context, this study aimed to quantify total Ti concentrations in highly consumed swimming crabs, squid, and shrimp from an important estuary located in southeastern Brazil. Ti concentrations were higher than those reported in most studies carried out worldwide. Animal length and weight, as well as, depth, transparency, dissolved oxygen, and salinity, significantly influence Ti concentrations in the animals. Human health risks were also noted after calculating a simulated exposure to titanium dioxide, especially considering the uncertainties regarding the effects of this element and the absence of regulatory limits.

Risk and Benefit Analysis of Fish Consumption in NW Mexico: Mercury, Selenium, and Fatty Acids

To balance the risks and benefits of fish consumption, selenium, fatty acids (DHA + EPA), and mercury in fishery products were determined. Analyzed products were canned tuna, frozen tuna (Thunnus albacares), smoked striped marlin (Tetrapturus audax), fresh Pacific sierra (Scomberomorus sierra), fresh dolphinfish (Coryphaena hippurus), fresh tilapia (Gerres cinereus), and fresh bullseye puffer (Sphoeroides annulatus). Mercury (μg g^-1 wet weight) ranged from 0.01 (dolphinfish) to 0.23 (bullseye puffer); Se ranged from 0.12 to 0.25. EPA + DHA ranged from 1.16 to 10.72 mg g^-1. Intake of EPA + DHA was comparable or above the recommended daily intake; Hg intake was below the reference dose but Se intake was below than recommended values for the different population groups. Considering the HBV_Se, fishery products had positive values; i.e., they are healthy food items. According to the interaction of Hg and Se and the rate of fishery product consumption, the risk for consumers is below one percent.

Chemical Content of Five Molluscan Bivalve Species Collected from South Korea: Multivariate Study and Safety Evaluation

Bivalves are a good source of nutrients but also a potential source of environmental contaminants, which could pose a risk for consumers. The aims of this study were: the determination of 16 elements by ICP-MS in 48 samples of five bivalve species purchased from market in Korea; the identification of elements useful for species classification using multivariate analyses; and the benefit-risk evaluation associated to the consumption of these bivalves. The highest difference among content of elements between species was found for Cd, Mn, Ni, Zn, and Fe. Partial last squares discriminant analysis revealed elements with a VIP score >1 which were considered as the most relevant for explaining certain species. As, Cd, Co, and Ni were found as taxonomical markers of V. philippinarum; Mn, Zn, Mg, and Na of A. irradians; and Cd, Ni, and Fe of M. yessoensis. These species could serve as good dietary sources of essential elements. Cd exposure by consumption of Manila clams is not representing a health risk for the Korean population; however, through consumption of Yesso scallops, 5.3% of the Korean population has a potential health risk. Removal of the digestive gland before eating will drastically reduce the amount of Cd ingested.

Mercury concentrations in Baja California Sur fish: Dietary exposure assessment

Total mercury concentrations ([THg]) in muscle were determined in commercial finfish and elasmobranchs from Baja California Sur (BCS), Mexico to evaluate dietary Hg exposure for BCS communities, including the relationship of trophic ecology, length and mass with [THg] that might drive future consumption advice (e.g., recommend limited consumption of large fish for some species). The [THg] ranged from 0.06 to 528.02 μg kg^-1 ww in finfish and 17.68-848.26 μg kg^-1 ww in elasmobranchs. Relative to the consumption threshold set for predatory fish in Mexico, all species had a concentration below 1000 μg kg^-1 ww. As expected, 16 (4.02%) and 75 (18.84%) individual fish were above advisory thresholds of 500 and 200 μg kg^-1 ww, respectively. The hazard quotients (HQs) in most species were significantly <1.0, only banded guitarfish showed a significant median HQ > 1.0. Thus, the relative level of risk of high Hg exposure is low for most species.

Assessment of the ecological and human health risks from metals in shrimp aquaculture environments in Central Java, Indonesia

The occurrence and contamination level of seven important toxic metals (Cd, Cu, Co, Cr, Hg, Pb, and Zn) and three additional metals (Al, Fe, and Mn) in the water, sediment, and shrimp muscle in aquaculture areas located in Central Java, Indonesia, were investigated. The results suggest that the majority of metals have higher concentrations in the inlet followed by the outlet and ponds. Cd dissolved in the waters exhibited the highest level in Pekalongan (3.15 ± 0.33 μg L^-1). Although Pb was not detected in the water, it was detected in the sediment, and the concentration ranged from 7.6 to 15.40 mg kg^-1 dw. In general, the heavy metal concentrations in the sediments were found to decrease in the sequence Al > Fe > Mn > Zn > Cr > Cu > Co > Pb. Concentrations below the effects range low level based on the Canadian sediment quality guidelines were found for Cr, Cu, Pb, and Zn, whereas moderate sediment pollution (25-75 mg kg^-1 dw) was observed for Cr (all regions), Cu (except in the Pekalongan region), and Zn (Brebes and Tegal regions) according to the US EPA standard. The status of the waters was evaluated by calculating a pollution index derived mostly from Mn and Zn. The ecological risk (geoaccumulation index (I_geo), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (ERI)) determined in the sediments indicated that all studied areas had low to moderate contamination. The concentrations of all metals in shrimp were generally below the maximum limits for seafood, except for Zn (in all stations), Pb, and Cr (Tegal and Pekalongan). The hazard index values for metals indicated that consuming shrimp would not have adverse effects on human health.

Concentrations of heavy metals in muscle and edible offal of pork in Nanjing city of China and related health risks

The concentrations of heavy metals, such as chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb), in different muscles and edible offal of consumed pork from the city of Nanjing and related health risks were evaluated. The results showed that the detected Hg concentrations from 6 of 80 samples exceeded the maximum allowable concentration (GB 2762-2017). Moreover, most of the edible offal, especially the kidneys, contained more heavy metals than the other parts, although the concentrations among the samples were significantly different (P < 0.05). In addition, the health risk evaluation revealed that the estimated daily intake of all the samples was far below the recommended limit, and all the target hazard quotients and total target hazard quotients were less than 1, which is considered safe for human health. Nevertheless, the Hg concentrations over the acceptable limit should receive sufficient attention, considering the long-term consumption of pork. PRACTICAL APPLICATION: Currently, no reports have been available on the heavy metal assessment of pork, though pork is widely consumed in many non-Muslim communities. In this study, the concentrations of heavy metals in different muscles and edible offal of consumed pork were determined and their related health risks were evaluated. This study will provide a significant reference to understand the quality and safety of pork in China or other similar developing countries.

Chemical analysis of Hg0-containing Hindu religious objects

Parad items used in Hindu practices and Ayurvedic medicines contain elemental mercury (Hg⁰) and have traditionally been used in prayer and to treat a variety of diseases including diabetes, heart conditions, and sexual dysfunction. These items are often referred to as amalgams of silver, and take the form of shivlings, statues of gods, necklaces, and other jewelry. Fourteen parad items were purchased from online vendors in India and the United States and analyzed. All items produced copious amounts of Hg⁰ vapor, with Hg⁰ concentrations exceeding 1,000,000 ng/m³ as measured using a Mercury Instruments Mercury Tracker 3000 IP atomic absorption spectrometer. Measured concentrations were highly variable, so a simple qualitative experiment employing a UV-C light source and a thin-layer chromatography plate impregnated with a fluorescent dye that glows green when irradiated at 254 nm allowed for the indirect visualization of the Hg⁰ being evolved. In addition, all items were screened using a hand-held X-ray fluorescence analyzer to estimate the concentration of Hg, Sn, Pb, As, and Cd on the surface of the item. Select samples were then digested in aqua regia and analyzed for Hg content using a direct mercury analyzer. All samples were found to exceed 20% by mass Hg. The digestates were analyzed using inductively-coupled plasma–optical emission spectrometry and were determined to be between 10–55% by mass Pb and contain up to 0.3% by mass As. While Article 4 of the Minamata Convention on Mercury specifically requires parties to stop importing, exporting, and manufacturing Hg-added products, products used in traditional and religious practices are excluded.

Heavy metal concentrations in commercial marine organisms from Xiangshan Bay, China, and the potential health risks

Commercial marine organisms were collected from the coast of Xiangshan Bay to investigate the concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and evaluate the potential health risks. The results indicated considerable variations in the heavy metal concentrations among six species groups, of them mollusks (seasnail, benthic bivalve, and oyster) generally contained relative high levels of most metals, followed by crustaceans (crab and shrimp), by contrast, fish had low concentrations of all metals, except Hg. Three heavy metal groups were identified to interpret the accumulative characteristics in the marine organisms. Spatial distributions illustrated the geographical variations of heavy metal concentrations in the sampling areas. Moreover, maricultured organisms demonstrated lower heavy metal concentrations than did the wild. Health risks of most heavy metals exposed from marine organism consumption were safe, except for As which is associated with the high target cancer risk values.

Methylmercury's chemistry: From the environment to the mammalian brain

Methylmercury is a neurotoxicant that is found in fish and rice. MeHg's toxicity is mediated by blockage of -SH and -SeH groups of proteins. However, the identification of MeHg's targets is elusive. Here we focus on the chemistry of MeHg in the abiotic and biotic environment. The toxicological chemistry of MeHg is complex in metazoans, but at the atomic level it can be explained by exchange reactions of MeHg bound to -S(e)H with another free -S(e)H group (R¹S(e)-HgMe + R²-S(e)H ↔ R¹S(e)H + R²-S(e)-HgMe). This reaction was first studied by professor Rabenstein and here it is referred as the "Rabenstein's Reaction". The absorption, distribution, and excretion of MeHg in the environment and in the body of animals will be dictated by Rabenstein's reactions. The affinity of MeHg by thiol and selenol groups and the exchange of MeHg by Rabenstein's Reaction (which is a diffusion controlled reaction) dictates MeHg's neurotoxicity. However, it is important to emphasize that the MeHg exchange reaction velocity with different types of thiol- and selenol-containing proteins will also depend on protein-specific structural and thermodynamical factors. New experimental approaches and detailed studies about the Rabenstein's reaction between MeHg with low molecular mass thiol (LMM-SH) molecules (cysteine, GSH, acetyl-CoA, lipoate, homocysteine) with abundant high molecular mass thiol (HMM-SH) molecules (albumin, hemoglobin) and HMM-SeH (GPxs, Selenoprotein P, TrxR1-3) are needed. The study of MeHg migration from -S(e)-Hg- bonds to free -S(e)H groups (Rabenstein's Reaction) in pure chemical systems and neural cells (with special emphasis to the LMM-SH and HMM-S(e)H molecules cited above) will be critical to developing realistic constants to be used in silico models that will predict the distribution of MeHg in humans.