A quantitative synthesis of mercury in commercial seafood and implications for exposure in the United States

An approach to assessing subsea pipeline-associated mercury release into the North Sea and its potential environmental and human health impact

Mercury is a naturally occurring heavy metal that has also been associated with anthropogenic sources such as cement production or hydrocarbon extraction. Mercury is a contaminant of concern as it can have a significant negative impact on organismal health when ingested. In aquatic environments, it bioaccumulates up the foodweb, where it then has the potential to impact human health. With the offshore hydrocarbon platforms in the North Sea nearing decommissioning, they must be assessed as a potential source for the environmental release of mercury. International treaties govern the handling of materials placed in the ocean. Studies have assessed the ecologic and economic benefits of (partial) in situ abandonment of the infrastructure as artificial reefs. This can be applied to pipelines after substantial cleaning to remove mercury accumulation from the inner surface. This work outlines the application of an approach to modelling marine mercury bioaccumulation for decommissioning scenarios in the North Sea. Here, in situ decommissioning of cleaned pipelines was unlikely to have a negative impact on the North Sea food web or human health. However, significant knowledge gaps have been determined, which must be addressed before all negative impacts on ecosystems and organismal health can be excluded.

Relationship of mercury and selenium in ocean fish frequently consumed in the Seychelles: A comparison to levels in ocean fish consumed in the US

We characterized mercury and selenium in the fish consumed in the Seychelles Islands to determine if their levels are similar to fish consumed in the US. A secondary aim was to examine whether fish weight and species predict mercury and selenium in fish consumed in the Seychelles. We measured total mercury (THg) and selenium (Se) content of 10 samples from each of the 19 most frequently consumed fish species in Seychelles and for each calculated the Se:Hg molar ratios and the Selenium Health Benefit Value Index (HBV Se). Linear regression models examined associations with weight and species. Average MeHg levels in fish ranged from less than 0.01 ppm (streamlined spinefoot) to 0.7 ppm (bludger trevally) with an overall mean of 0.21 ± 0.23 ppm. Average Se levels ranged from 0.34 ppm (blue-barred parrot fish) to 0.93 ppm (blue-lined large-eye bream) with a mean of 0.54 ± 0.23 ppm. All fish species had a mean Se:Hg molar ratio > 1 and positive mean HBV Se index values. Weight was strongly predictive of MeHg and Se:Hg molar ratio, both across and within most species, but was less predictive of Se and HBV Se. Our study demonstrated that fish consumed in Seychelles have mercury and selenium content similar to that of fish consumed in the US. Fish in both countries have favorable positive values for Se:Hg molar ratios and HBV Se indexes. Because mercury and selenium concentrations in fish are similar to those in the US but fish consumption is substantially higher in Seychelles, the Seychellois make an ideal population in which to determine if there are adverse effects of prenatal, postnatal, and lifetime low dose MeHg exposure from fish consumption.

An assessment of approaches and techniques for estimating water pollution releases from aquaculture production facilities

The rapid expansion of the aquaculture industry raises concerns about water pollution from aquaculture production facilities (APFs). APFs release pollutants, including fish feed and feces, threatening the environment. The United Nations has introduced regulatory tools like the National Baseline Budget of pollutants (NBB) and Pollutant Release and Transfer Registers (PRTRs) to monitor pollution. However, these tools lack specific capabilities for estimating aquaculture-related pollution, especially from mariculture non-point sources (NPS). The United Nations Programme for the Assessment and Control of Marine Pollution in the Mediterranean (UNEP/MAP) stresses the need for an inventory and guidance document. Our comprehensive literature review focused on (1) NPS discharges of specific pollutants from APFs, (2) methods for estimating potential pollution releases from aquaculture, and (3) compiling information into a guidance document summarizing estimation methods. The geographical coverage of our study includes Europe, Australia, the USA, Canada, and East/Southeast Asia.

Interaction of Naturally Occurring Phytoplankton with the Biogeochemical Cycling of Mercury in Aquatic Environments and Its Effects on Global Hg Pollution and Public Health

The biogeochemical cycling of mercury in aquatic environments is a complex process driven by various factors, such as ambient temperature, seasonal variations, methylating bacteria activity, dissolved oxygen levels, and Hg interaction with dissolved organic matter (DOM). As a consequence, part of the Hg contamination from anthropogenic activity that was buried in sediments is reinserted into water columns mainly in highly toxic organic Hg forms (methylmercury, dimethylmercury, etc.). This is especially prominent in the coastal shallow waters of industrial regions worldwide. The main entrance point of these highly toxic Hg forms in the aquatic food web is the naturally occurring phytoplankton. Hg availability, intake, effect on population size, cell toxicity, eventual biotransformation, and intracellular stability in phytoplankton are of the greatest importance for human health, having in mind that such Hg incorporated inside the phytoplankton cells due to biomagnification effects eventually ends up in aquatic wildlife, fish, seafood, and in the human diet. This review summarizes recent findings on the topic of organic Hg form interaction with natural phytoplankton and offers new insight into the matter with possible directions of future research for the prevention of Hg biomagnification in the scope of climate change and global pollution increase scenarios.

Risk-benefit assessment of methylmercury and n-3 polyunsaturated fatty acids through fish intake by pregnant women in Shanghai, China: Findings from the Shanghai Diet and Health Survey

BACKGROUND

Fish and shellfish contain nutrients essential for fetal health, especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The concern of mercury (Hg) pollution limits fish consumption among women in pregnancy, which could adversely affect child development. This study aimed to conduct risk-benefit assessment and provide recommendations for fish intake by pregnant women in Shanghai, China.

METHODS

Secondary analysis was conducted using cross-sectional data from a representative sample of the Shanghai Diet and Health Survey (SDHS) (2016-2017), China. Dietary intakes of Hg and DHA + EPA were calculated from the food frequency questionnaire (FFQ) on fish items and 24hr recall record. Raw fish samples (59 common species of fish in Shanghai) were purchased in local markets and their concentrations of DHA, EPA and Hg were measured. Net IQ points gain was used to evaluate the health risk and benefit at a population level by FAO/WHO model. Recommended fish (i.e., high- DHA + EPA and low-level MeHg) were defined, and then the proportion of those hit 5.8 IQ points were simulated with their consumption frequency for 1, 2 and 3 times per week.

RESULTS

The average consumption of fish and shellfish was 66.24 g/d among pregnant women in Shanghai. The mean concentrations of Hg and EPA + DHA in fish species most commonly consumed in Shanghai were 0.179 mg/kg and 0.374 g/100 g, respectively. Only 1.4% of the population exceeded the MeHg reference dose of 0.1 μg/kg·bw/d, whereas 81.3% of those who did not meet the recommended daily intakes of 250 mg EPA + DHA. In FAO/WHO model, the proportion of 28.4% reached the maximum IQ points gain. Along with the increase of "recommended fish" consumed, the simulated values of the proportion raised to 74.5, 87.3 and 91.9%, respectively.

CONCLUSION

The pregnant women in Shanghai, China had an adequate fish consumption with low-level Hg exposure, but balancing the benefits of fish intake and risk of potential Hg exposure was still a challenge. It is necessary to define a local level of "recommended fish" consumption for developing dietary recommendations for pregnant women.

Total mercury, methylmercury, and selenium concentrations in blue marlin Makaira nigricans from a long-term dataset in the western north Atlantic

Mercury in seafood is a neurotoxicant that threatens human health. Dynamic rates of mercury emission, re-emission, and atmospheric deposition warrant studies into mercury concentrations in fish because many are consumed by humans and can serve as sentinels of mercury levels in the environment. We modeled trends in total mercury content in an apex marine fish predator, Atlantic blue marlin Makaira nigricans, whose muscle tissues were opportunistically sampled from North Carolina (USA) sportfishing tournaments over a discontinuous time period: between 1975 and 77 and 1998-2021 (n = 148). The model-estimated influence of marlin weight on total mercury concentration was constant across years (shared slope) allowing for comparisons of weight-corrected mercury concentrations among years. Weight-corrected total mercury concentrations revealed an inter-decadal decline of approximately 45 % between the 1970s and late 1990s and then variable but relatively stable concentrations through 2021. The mean (SD) wet weight concentration of total mercury was 9.47 (4.11) from 1975 to 77 and 4.17 (2.61) from 2020 to 2021. Methylmercury and selenium were measured on a subset of fish to address questions related to human health and consumption. Methylmercury levels (mean = 0.72 μg/g) were much lower than total mercury (mean = 4.69 μg/g) indicating that total mercury is not a good proxy for methylmercury in Atlantic blue marlin. Selenium, examined as a Se:Hg molar ratio and as a selenium health benefit value (HBV_Se), showed high protective value against mercury toxicity. Long-term trends in the concentration of mercury in blue marlin should continue to be monitored to determine whether policies to mitigate anthropogenic contributions to global mercury are achieving their intended goals and to provide information to inform safe human consumption.

Persistent and toxic chemical pollutants in fish consumed by Asians in Chicago, United States

Consumption of seafood brings health benefits but may increase the ingestion of contaminants. Compared with other ethnic groups in the U.S., Asians consume seafood more frequently. However, there is little information about how culturally specific fish consumption contributes to exposure to toxicants. In this work, we surveyed fish consumption among Chinese, Korean and Vietnamese communities and purchased 103 seafood samples from local markets in Chicago. Each sample was analyzed for mercury (Hg) and 92 organic chemicals including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and Dechlorane Plus and related compounds (DPs). The rank order of pollutant concentration in all samples was Hg ≫ Σ₆₆PCBs > Σ₁₇OCPs > Σ₈PBDEs > Σ₈DPs. Positive correlations were noted among most contaminant groups. Bluefish, pike and tuna steak had the highest mean Hg (>1 mg/kg). The mean Σ₆₆PCBs was highest in pike and bluefish (>100 ng/g) followed by pollock and mackerel (>40 ng/g). Overall, octopus, shrimp and tilapia were the least contaminated; while pike, bluefish, and pollock were the most contaminated. Omega-3 fatty acids were more strongly affiliated with the organic contaminants than mercury. A risk assessment identified seven types of fish that should have consumption limitations and six that should not be consumed. For these seafoods, consumption advice based on Hg levels would adequately protect health. In the survey participants, 17% of seafood mass consumed is from types of fish that should be limited to 1 or 2 meals/week, while 7% of the seafood mass consumed comes from types that should not be consumed at all. This work adds additional contaminants to the profile of health risks resulting from fish consumption among Asian Americans, which can be used in interventions aimed at conserving consumption of healthy fish while avoiding contaminants.

Risk assessment for seafood consumers exposed to mercury and other trace elements in fish from Long Island, New York, USA

We determined concentrations of Hg, Pb, Cd, Cr, As, Ni, Ag, Se, Cu, and Zn in muscle tissue of six commonly consumed Long Island fish species (black seabass, bluefish, striped bass, summer flounder, tautog, and weakfish, total sample size = 1211) caught off Long Island, New York in 2018 and 2019. Long-term consumption of these coastal fish could pose health risks largely due to Hg exposure; concentrations of the other trace elements were well below levels considered toxic for humans. By combining the measured Hg concentrations in the fish (means ranging from 0.11 to 0.27 mg/kg among the fish species), the average seafood consumption rate, and the current US EPA Hg reference dose (0.0001 mg/kg/d), it was concluded that seafood consumption should be limited to four fish meals per month for adults for some fish (bluefish, tautog) and half that for young children. Molar ratios of Hg:Se exceeded 1 for some black seabass, bluefish, tautog, and weakfish.

Compound-Specific Stable Isotope Analysis Provides New Insights for Tracking Human Monomethylmercury Exposure Sources

Monomethylmercury (MMHg) exposure can induce adverse neurodevelopmental effects in humans and is a global environmental health concern. Human exposure to MMHg occurs predominately through the consumption of fishery foods and rice in Asia, but it is challenging to quantify these two exposure sources. Here, we innovatively utilized MMHg compound-specific stable isotope analyses (MMHg-CSIA) of the hair to quantify the human MMHg sources in coastal and inland areas, where fishery foods and rice are routinely consumed. Our data showed that the fishery foods and rice end members had distinct Δ¹⁹⁹Hg_MMHg values in both coastal and inland areas. The Δ¹⁹⁹Hg_MMHg values of the human hair were comparable to those of fishery foods but not those of rice. Positive shifts in the δ²⁰²Hg_MMHg values of the hair from diet were observed in the study areas. Additionally, significant differences in δ²⁰²Hg versus Δ¹⁹⁹Hg were detected between MMHg and inorganic Hg (IHg) in the human hair but not in fishery foods and rice. A binary mixing model was developed to estimate the human MMHg exposures from fishery foods and rice using Δ¹⁹⁹Hg_MMHg data. The model results suggested that human MMHg exposures were dominated (>80%) by fishery food consumption and were less affected by rice consumption in both the coastal and inland areas. This study demonstrated that the MMHg-CSIA method can provide unique information for tracking human MMHg exposure sources by excluding the deviations from dietary surveys, individual MMHg absorption/demethylation efficiencies, and the confounding effects of IHg.

Regional variation in mercury bioaccumulation among NW Atlantic Golden (Lopholatilus chamaeleonticeps) and Blueline (Caulolatilus microps) Tilefish

Mercury (Hg) concentrations in fishes from the NW Atlantic Ocean pose concern due to the importance of this region to U.S. fisheries harvest. In this study, total Hg (THg) concentrations and nitrogen stable isotope (δ¹⁵N) values were quantified in muscle tissues sampled from Golden (Lopholatilus chamaeleonticeps) and Blueline (Caulolatilus microps) Tilefish collected during a fishery-independent survey conducted in the NW Atlantic to compare bioaccumulation patterns between these species. Total Hg concentrations averaged (±SD) 0.4 ± 0.4 μg/g dry weight (d.w.) for L. chamaeleonticeps and 1.1 ± 0.7 μg/g d.w. for C. microps with <2% of all sampled fish, those >70 cm fork length, exceeding the most restrictive USEPA regulatory guidelines for human consumption (THg > 0.46 μg/g w.w.), when converted to wet weight concentrations. The THg concentrations reported here for individuals from the NW Atlantic stock are comparable to those reported for similarly sized individuals collected from the SW Atlantic stock but notably lower than those reported for Gulf of Mexico L. chamaeleonticeps, indicating different Hg exposure and assimilation kinetics for fish from the NW Atlantic, and highlights the broad geographic variability of Hg bioaccumulation among Tilefish stocks. Caulolatilus microps had higher δ¹⁵N values relative to L. chamaeleonticeps and a pattern of decreasing THg concentrations was also present from south to north across the study range. It is concluded that this trophic difference and spatial pattern in Tilefish THg concentrations emphasizes the habitat and resource partitioning mechanisms described for these sympatric species that permits their coexistence in the continental shelf environment. Importantly, regional variability in THg concentrations accentuate the possible roles of fine-scale biotic and abiotic processes that can act to regulate Hg bioaccumulation among individuals and species.

Essential and toxic elements in sardines and tuna on the Colombian market

The presence of metals in canned fish has been associated with adverse effects on human health. The aim of this study was to evaluate risk-based fish consumption limits based on the concentrations of eight essential elements and four elements of toxicological concern in sardines and tuna brands commercially available in the Latin American canned goods market. One brand of canned sardines and six of canned tuna were collected and evaluated by ICP-MS and direct mercury analysis. The Hg content was much higher than that previously observed in scientific literature. According to the calculated hazard quotients, all brands may present some risk in terms of this element, especially brand F in which levels up to 3.1 µg/g were measured. Sardine samples surpassed the maximum limits of Mn and As. Stricter quality control in retail chains and industries should be implemented in order to guarantee safe levels in fishery products.

Amyotrophic Lateral Sclerosis Risk, Family Income, and Fish Consumption Estimates of Mercury and Omega-3 PUFAs in the United States

Most amyotrophic lateral sclerosis (ALS) cases are considered sporadic, without a known genetic basis, and lifestyle factors are suspected to play an etiologic role. We previously observed increased risk of ALS associated with high nail mercury levels as an exposure biomarker and thus hypothesized that mercury exposure via fish consumption patterns increases ALS risk. Lifestyle surveys were obtained from ALS patients (n = 165) and n = 330 age- and sex-matched controls without ALS enrolled in New Hampshire, Vermont, or Ohio, USA. We estimated their annual intake of mercury and omega-3 polyunsaturated fatty acid (PUFA) via self-reported seafood consumption habits, including species and frequency. In our multivariable model, family income showed a significant positive association with ALS risk (p = 0.0003, adjusted for age, sex, family history, education, and race). Neither the estimated annual mercury nor omega-3 PUFA intakes via seafood were associated with ALS risk. ALS incidence is associated with socioeconomic status; however, consistent with a prior international study, this relationship is not linked to mercury intake estimated via fish or seafood consumption patterns.

Effects of methylmercury on the early life stages of an estuarine forage fish using two different dietary sources

Marine fish accumulate methylmercury (MeHg) to elevated concentrations, often higher than in freshwater systems. As a neurotoxic compound, high MeHg tissue concentrations could affect fish behavior which in turn could affect their populations. We examined the sublethal effects of MeHg on larvae of the Sheepshead minnow (Cyprinodon variegatus), an estuarine fish, using artificial or natural diets with varying MeHg concentrations (0-4.8 ppm). Larvae were fed control and MeHg-contaminated diets at low or normal (10% of their body mass) daily food rations from 7 to 29 days when they reached juvenile stage. Growth, respiration, swimming activity and prey capture ability were assessed. Food ration affected Hg toxicity in our study. Natural diets containing 3.2 ppm MeHg had no impacts on growth and swimming in fish that were fed normal food rations but depressed growth and swimming at low food rations. MeHg toxicity did not differ between artificial and natural foods, however fish accumulated more MeHg from the former. Artificial food containing 4.8 ppm MeHg only affected prey capture after 21 days of exposure. Sheepshead minnows, a forage fish species occupying a low trophic level in coastal waters, can be MeHg tolerant, especially when food is abundant, and can serve as an enriched Hg source for higher trophic level predators.

A synthesis of patterns of environmental mercury inputs, exposure and effects in New York State

Mercury (Hg) pollution is an environmental problem that adversely affects human and ecosystem health at local, regional, and global scales-including within New York State. More than two-thirds of the Hg currently released to the environment originates, either directly or indirectly, from human activities. Since the early 1800s, global atmospheric Hg concentrations have increased by three- to eight-fold over natural levels. In the U.S., atmospheric emissions and point-source releases to waterways increased following industrialization into the mid-1980s. Since then, water discharges have largely been curtailed. As a result, Hg emissions, atmospheric concentrations, and deposition over the past few decades have declined across the eastern U.S. Despite these decreases, Hg pollution persists. To inform policy efforts and to advance public understanding, the New York State Energy Research and Development Authority (NYSERDA) sponsored a scientific synthesis of information on Hg in New York State. This effort includes 23 papers focused on Hg in atmospheric deposition, water, fish, and wildlife published in Ecotoxicology. New York State experiences Hg contamination largely due to atmospheric deposition. Some landscapes are inherently sensitive to Hg inputs driven by the transport of inorganic Hg to zones of methylation, the conversion of inorganic Hg to methylmercury, and the bioaccumulation and biomagnification along food webs. Mercury concentrations exceed human and ecological risk thresholds in many areas of New York State, particularly the Adirondacks, Catskills, and parts of Long Island. Mercury concentrations in some biota have declined in the Eastern Great Lakes Lowlands and the Northeastern Highlands over the last four decades, concurrent with decreases in water releases and air emissions from regional and U.S. sources. However, widespread changes have not occurred in other ecoregions of New York State. While the timing and magnitude of the response of Hg levels in biota varies, policies expected to further diminish Hg emissions should continue to decrease Hg concentrations in food webs, yielding benefits to the fish, wildlife, and people of New York State. Anticipated improvements in the Hg status of aquatic ecosystems are likely to be greatest for inland surface waters and should be roughly proportional to declines in atmospheric Hg deposition. Efforts that advance recovery from Hg pollution in recent years have yielded significant progress, but Hg remains a pollutant of concern. Indeed, due to this extensive compilation of Hg observations in biota, it appears that the extent and intensity of the contamination on the New York landscape and waterscape is greater than previously recognized. Understanding the extent of Hg contamination and recovery following decreases in atmospheric Hg deposition will require further study, underscoring the need to continue existing monitoring efforts.

An assessment of temporal trends in mercury concentrations in fish

The importance of fish consumption as the primary pathway of human exposure to mercury and the establishment of fish consumption advisories to protect human health have led to large fish tissue monitoring programs worldwide. Data on fish tissue mercury concentrations collected by state, tribal, and provincial governments via contaminant monitoring programs have been compiled into large data bases by the U.S. Environmental Protection Agency's Great Lakes National Monitoring Program Office (GLNPO), the Ontario Ministry of the Environment's Fish Contaminants Monitoring and Surveillance Program (FMSP), and many others. These data have been used by a wide range of governmental and academic investigators worldwide to examine long-term and recent trends in fish tissue mercury concentrations. The largest component of the trend literature is for North American freshwater species important in recreational fisheries. This review of temporal trends in fish tissue mercury concentrations focused on published results from freshwater fisheries of North America as well as marine fisheries worldwide. Trends in fish tissue mercury concentrations in North American lakes with marked overall decreases were reported over the period 1972-2016. These trends are consistent with reported mercury emission declines as well as trends in wet deposition across the U.S. and Canada. More recently, a leveling-off in the rate of decreases or increases in fish tissue mercury concentrations has been reported. Increased emissions of mercury from global sources beginning between 1990 and 1995, despite a decrease in North American emissions, have been advanced as an explanation for the observed changes in fish tissue trends. In addition to increased atmospheric deposition, the other factors identified to explain the observed mercury increases in the affected fish species include a systematic shift in the food-web structure with the introduction of non-native species, creating a new or expanding role for sediments as a net source for mercury. The influences of climate change have also been identified as contributing factors, including considerations such as increases in temperature (resulting in metabolic changes and higher uptake rates of methylmercury), increased rainfall intensity and runoff (hydrologic export of organic matter carrying Hg^II from watersheds to surface water), and water level fluctuations that alter either the methylation of mercury or the mobilization of monomethylmercury. The primary source of mercury exposure in the human diet in North America is from the commercial fish and seafood market which is dominated (>90%) by marine species. However, very little information is available on mercury trends in marine fisheries. Most of the data used in the published marine trend studies are assembled from earlier reports. The data collection efforts are generally intermittent, and the spatial and fish-size distribution of the target species vary widely. As a result, convincing evidence for the existence of fish tissue mercury trends in marine fish is generally lacking. However, there is some evidence from sampling of large, long-lived commercially-important fish showing both lower mercury concentrations in the North Atlantic in response to reduced anthropogenic mercury emission rates in North America and increases in fish tissue mercury concentrations over time in the North Pacific in response to increased mercury loading.

Minor effects of dietary methylmercury on growth and reproduction of the sheepshead minnow Cyprinodon variegatus and toxicity to their offspring

Methylmercury (MeHg) is a neurotoxic compound that is found in virtually all fish and biomagnifies in aquatic food webs. Although MeHg concentrations in marine and estuarine fish are often elevated, the impacts of MeHg on marine and estuarine fish have largely been understudied. To evaluate the impact of dietary MeHg on marine fish reproduction and effects on their offspring, female juvenile sheepshead minnows (Cyprinodon variegatus) at three months of age were experimentally exposed to MeHg-contaminated diets for two months and then paired with Hg-free males for spawning. Egg production, hatching success of embryos, time to hatching, survival of larvae, growth of larvae and swimming behavior of larvae were determined. Selenium (Se) was also measured and Se/Hg molar ratios were calculated to assess whether Se reduced MeHg toxicity. MeHg had no significant impact on fish reproduction or on survival and growth of larvae. Larvae produced by MeHg-exposed mothers had concentrations of Hg about 1 ppm (dry wt), or about 12% of that in the muscle of their mothers and consistently displayed 6-15% increased swimming speed relative to controls; the ecological significance of this moderate effect on swimming speed requires further study. The Se/Hg molar ratios in these fish, which were >1 in controls (adults and larvae) and MeHg-exposed larvae but <1 in Hg-exposed adults, did not correlate with MeHg effects. The sheepshead minnow, at a low trophic level, appears to have a high tolerance of MeHg; however, it can pass MeHg to higher trophic levels in marine ecosystems where upper level predators have MeHg concentrations sometimes exceeding US FDA safety limits of 1 ppm wet wt.

Risk-Benefit Assessment for Total Mercury, Arsenic, Selenium, and Omega-3 Fatty Acids Exposure from Fish Consumption in Jamaica

Fish is important in the traditional diet of Jamaicans, and the fishing industry contributes to social and economic development, as well as food security in Jamaica. However, there are associated health risks from contaminant exposure. The aim of this paper was to use risk-benefit analysis methods to determine the best fish species for consumption. Composite samples consisting of 14 fish species were collected from major fishing villages in 2016 and measured for total mercury, arsenic, selenium, and omega-3 fatty acids (EPA and DHA). Food frequency questionnaires were randomly distributed to 400 participants from different locations on the island. Participants were asked to identify the types of fish, portion size, and the frequency of consumption. An estimate of their weight was also recorded. Total mercury concentrations in fish samples ranged from 0.003 to 0.215 μg/g. The range of arsenic concentrations was 0.11 to 7.8 μg/g. The range of selenium concentrations was 0.302 μg/g to 1.08 μg/g. The mean omega-3 fatty acid concentration was 123.1 ± 93.6 mg/100 g. The fish consumption rates range from 3.2 to 1132.8 g/day. Cod fish was the most consumed species at 23.2 g/day. Four risk-benefit analysis methods were able to recommend four fish species that were best for consumption based on the levels of mercury, arsenic, selenium, and omega-3 fatty acids. They were doctorfish, parrotfish, snappers, and cod fish. The results of this study concluded that there was a low risk of mercury exposure from fish consumed in Jamaica.

Mercury concentrations in store-bought shrimp

Most mercury exposure to humans comes from consumption of fish and shellfish; however, mercury concentrations are not known for all available seafood, particularly shrimp. Our objective was to estimate the concentration of mercury in a variety of store-bought shrimp and then to compare total mercury concentrations to other information such as brand, harvest type, and total fat. We sampled a total of n = 159 shrimp from 10 different brands. Across 10 brands of shrimp, there was a significant effect of brand, with mean mercury concentrations among brands varying by up to an order of magnitude. We found no significant differences comparing shrimp between two capture types (wild-caught and farm-raised), which was perfectly collinear to whether shrimp were domestic or foreign. We did detect significant differences in mercury levels among different amounts of total fat in shrimp, with the lowest fat shrimp (1 g) having significantly more mercury than the highest fat shrimp (2 g). Although our results confirm that shrimp contains relatively low levels of mercury and is generally considered a good choice for consumers, this study is the first to report significant differences in mercury among both brands of shrimp and total fat content in shrimp.

Mercury bioaccumulation in Tilefish (Lopholatilus chamaeleonticeps) from offshore waters of South Carolina, USA

Mercury (Hg) concentrations in Tilefish (Lopholatilus chamaeleonticeps) have been reported to be one of the highest of all fish species, resulting in advisories that, historically, have recommended zero consumption. The current study assesses Hg bioaccumulation in Tilefish targeted by the commercial fisheries operating off the coast of South Carolina, USA. We provide results for an under-sampled region and explore how life history potentially impacts Hg uptake in Tilefish. Mercury concentration in Tilefish muscle tissue ranged from 0.10 to 0.99 ppm, with a mean of 0.23 ppm (n = 63). The majority of Tilefish samples (95%) were within the "Good Choices" range for consuming at least one serving per week, with 62% being within the range considered best for eating two meals a week", per suggestion by the US EPA and US FDA (2017). The present study of Tilefish from the western Atlantic further substantiates the importance of monitoring Hg in commercial fish species regionally.

Significant elevation of human methylmercury exposure induced by the food trade in Beijing, a developing megacity

Methylmercury (MeHg) poses health risks to humans worldwide. The investigation of a longer chain of biogeochemical MeHg transport from production to consumption than that addressed in previous studies could provide additional scientific foundation for the reduction of risks. The main objective of this study is to identify the impacts of the interregional food trade along with the age, gender and socioeconomic status of people on human MeHg exposure in a developing megacity. Based on a field investigation, sampling and measurements, we provide experimental evidence regarding the substantial displacement of human MeHg exposure from production areas to consumption areas induced by the food trade. In 2018, 20% and 64% of the exposure in Beijing originated from the international and interprovincial food trade, respectively. Meanwhile, the ingestion of fish contributed 79% to the total exposure, followed by rice (4.4%), crab (3.8%) and shrimp (2.7%), and the exposure risk in urban districts was higher than that in rural areas by a factor of 2.2. A significantly higher contribution of imported deep-sea species to exposure among young people than among older people was observed (P < 0.01**), and a larger contribution of the international food trade to the MeHg exposure risk for women of childbearing age (average: 27%) than that among other groups (average: 10%) was found. Overall, our efforts demonstrate the dramatic impact of the food trade on MeHg exposure in a developing megacity, and we suggest that MeHg-susceptible populations in China should choose indigenous fish species (e.g., hairtail, yellow croaker and carp species) rather than imported deep-sea species as their dietary protein source.

Sustainable Seafood and Vegetable Production: Aquaponics as a Potential Opportunity in Urban Areas

Global population growth will increase pressures on current food systems in order to supply adequate protein and produce to the increasingly urban world population. The environmental impact of food production is a critical area of study as it influences water and air quality, ecosystem functions, and energy consumption. Aquaponics (in which seafood and vegetables are grown in a closed-loop system) has the potential to reduce the environmental impact of food production. A review of the current environmental and economic considerations is provided in order to identify current research gaps. Research gaps exist with respect to 1) diversity of aquatic and plant species studied; 2) inconsistent bounds, scope, and lifetime across studies; 3) diverse allocation of the environmental and economic impacts to the coproducts; 4) scale of systems considered; 5) transportation of produced food; and 6) presence of heavy metals, pests, and pathogens with human health implications. These aspects require increased attention to close the existing gaps prior to widescale deployment of these systems for increased sustainable food production toward satisficing human needs. Integr Environ Assess Manag 2019;00:1-12. © 2019 SETAC.

Fish, Shellfish, and Children's Health: An Assessment of Benefits, Risks, and Sustainability

American children eat relatively little fish and shellfish in comparison with other sources of animal protein, despite the health benefits that eating fish and shellfish may confer. At the same time, fish and shellfish may be sources of toxicants. This report serves to inform pediatricians about available research that elucidates health risks and benefits associated with fish and shellfish consumption in childhood as well as the sustainability of fish and shellfish harvests.

Inter-species differences of total mercury and methylmercury in farmed fish in Southern China: Does feed matter?

China is now the largest producer of marine farmed fish and there is a considerable concern of seafood safety due to potential mercury contamination. We analyzed both the total mercury (THg) and methylmercury (MeHg) concentrations in nine species of commercial fish from two marine-cage farms in Southern China. ¹³C and ¹⁵N stable isotopes were concurrently analyzed to identify the artificial feed sources and the trophic levels of farmed fish. Mercury concentrations of all species were much lower than the human health screening values and safety limits established by different countries. Mercury levels in artificial pellets were the main determinants of Hg accumulation in fish between two sites, while somatic growth dilution and size also played an important role. Among the different fish tissues, muscle was a major reservoir for Hg and contained the highest ratio of MeHg/THg, and liver was the second important organ for Hg accumulation in most fish species. Intestine was a critical organ for Hg biotransformation with its %MeHg differing greatly among different fish species. δ¹⁵N analysis could not be used to determine the trophic levels in culturing systems where artificial practices were involved. Based on the δ¹³C signatures, five species of fish were identified to solely feed on the artificial pellets, yet the Hg bioaccumulation differed significantly among these species. We therefore concluded that Hg bioaccumulation in different fish species may be dependent on their internal Hg biotransformation as well as their biokinetics.

Tracking Declines in Mercury Exposure in the New York City Adult Population, 2004-2014

Mercury is a toxic metal that can be measured in human blood and urine. Population-based biomonitoring from 2004 guided New York City (NYC) Department of Health and Mental Hygiene (DOHMH) efforts to reduce exposures by educating the public about risks and benefits of fish consumption-a predominant source of exposure in the general population-and removing mercury-containing skin-lightening creams and other consumer products from the marketplace. We describe changes in exposures over the past decade in relation to these local public health actions and in the context of national changes by comparing mercury concentrations measured in blood (1201 specimens) and urine (1408 specimens) from the NYC Health and Nutrition Examination Survey (NYC HANES) 2013-2014 with measurements from NYC HANES 2004 and National Health and Nutrition Examination Surveys (NHANES) 2003-2004 and 2013-2014. We found that NYC adult blood and urine geometric mean mercury concentrations decreased 46% and 45%, respectively. Adult New Yorkers with blood mercury concentration ≥ 5 μg/L (the New York State reportable level) declined from 24.8% (95% CL = 22.2%, 27.7%) to 12.0% (95% CL = 10.1%, 14.3%). The decline in blood mercury in NYC was greater than the national decline, while the decline in urine mercury was similar. As in 2004, Asian New Yorkers had higher blood mercury concentrations than other racial/ethnic groups. Foreign-born adults of East or Southeast Asian origin had the highest prevalence of reportable levels (29.7%; 95% CL = 21.0%, 40.1%) across sociodemographic groups, and Asians generally were the most frequent fish consumers, eating on average 11 fish meals in the past month compared with 7 among other groups (p < 0.001). Fish consumption patterns were similar over time, and fish continues to be consumed more frequently in NYC than nationwide (24.7% of NYC adults ate fish ten or more times in the past 30 days vs. 14.7% nationally, p < 0.001). The findings are consistent with the hypothesis that blood mercury levels have declined in part because of local and national efforts to promote consumption of lower mercury fish. Local NYC efforts may have accelerated the reduction in exposure. Having "silver-colored fillings" on five or more teeth was associated with the highest 95th percentile for urine mercury (4.06 μg/L; 95% CL = 3.1, 5.9). An estimated 5.5% of the adult population (95% CL = 4.3%, 7.0%) reported using a skin-lightening cream in the past 30 days, but there was little evidence that use was associated with elevated urine mercury in 2013-14.

Expression of Genes Involved in Stress, Toxicity, Inflammation, and Autoimmunity in Relation to Cadmium, Mercury, and Lead in Human Blood: A Pilot Study

There is growing evidence of immunotoxicity related to exposure to toxic trace metals, and an examination of gene expression patterns in peripheral blood samples may provide insights into the potential development of these outcomes. This pilot study aimed to correlate the blood levels of three heavy metals (mercury, cadmium, and lead) with differences in gene expression in 24 participants from the Long Island Study of Seafood Consumption. We measured the peripheral blood mRNA expression of 98 genes that are implicated in stress, toxicity, inflammation, and autoimmunity. We fit multiple linear regression models with multiple testing correction to correlate exposure biomarkers with mRNA abundance. The mean blood Hg in this cohort was 16.1 &micro;g/L, which was nearly three times the Environmental Protection Agency (EPA) reference dose (5.8 &micro;g/L). The levels of the other metals were consistent with those in the general population: the mean Pb was 26.8 &micro;g/L, and the mean Cd was 0.43 &micro;g/L. The expression of three genes was associated with mercury, four were associated with cadmium, and five were associated with lead, although none were significant after multiple testing correction. Little evidence was found to associate metal exposure with mRNA abundance for the tested genes that were associated with stress, toxicity, inflammation, or autoimmunity. Future work should provide a more complete picture of physiological reactions to heavy metal exposure.

Mercury, omega-3 fatty acids, and seafood intake are not associated with heart rate variability or QT interval

Mercury (Hg), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) concentrations differ across seafood types. Our aim was to investigate the association of Hg, EPA, and DHA, as well as avid consumption of diverse seafood types, with cardiovascular variables heart rate variability (HRV) and QT interval duration (QTc) in a contemporary population. We measured HRV and QTc by Holter monitor, EPA and DHA in plasma, total Hg in whole blood, and possible confounders in 94 avid seafood consumers from Long Island, NY. Participants had mean Hg of 8.4 mcg/L, mean EPA of 1.2%, and mean DHA of 3.7% of total fatty acids. Adjusted for possible confounders, EPA+DHA, Hg, and total seafood consumption were not associated with HRV or QTc. Associations with consumption of specific seafood types were suggested (eg, tuna steak with QTc and anchovies with HRV) but require verification.

Mercury Stable Isotopes Reveal Influence of Foraging Depth on Mercury Concentrations and Growth in Pacific Bluefin Tuna

Pelagic ecosystems are changing due to environmental and anthropogenic forces, with uncertain consequences for the ocean's top predators. Epipelagic and mesopelagic prey resources differ in quality and quantity, but their relative contribution to predator diets has been difficult to track. We measured mercury (Hg) stable isotopes in young (<2 years old) Pacific bluefin tuna (PBFT) and their prey species to explore the influence of foraging depth on growth and methylmercury (MeHg) exposure. PBFT total Hg (THg) in muscle ranged from 0.61 to 1.93 μg g^-1 dw (1.31 μg g^-1 dw ±0.37 SD; 99% ± 6% MeHg) and prey ranged from 0.01 to 1.76 μg g^-1 dw (0.13 μg g^-1 dw ±0.19 SD; 85% ± 18% MeHg). A systematic decrease in prey δ²⁰²Hg and Δ¹⁹⁹Hg with increasing depth of occurrence and discrete isotopic signatures of epipelagic prey (δ²⁰²Hg: 0.74 to 1.49‰; Δ¹⁹⁹Hg: 1.76-2.96‰) and mesopelagic prey (δ²⁰²Hg: 0.09 to 0.90‰; Δ¹⁹⁹Hg: 0.62-1.95‰) allowed the use of Hg isotopes to track PBFT foraging depth. An isotopic mixing model was used to estimate the dietary proportion of mesopelagic prey in PBFT, which ranged from 17% to 55%. Increased mesopelagic foraging was significantly correlated with slower growth and higher MeHg concentrations in PBFT. The slower observed growth rates suggest that prey availability and quality could reduce the production of PBFT biomass.

Mercury transport and human exposure from global marine fisheries

Human activities have increased the global circulation of mercury, a potent neurotoxin. Mercury can be converted into methylmercury, which biomagnifies along aquatic food chains and leads to high exposure in fish-eating populations. Here we quantify temporal trends in the ocean-to-land transport of total mercury and methylmercury from fisheries and we estimate potential human mercury intake through fish consumption in 175 countries. Mercury export from the ocean increased over time as a function of fishing pressure, especially on upper-trophic-level organisms. In 2014, over 13 metric tonnes of mercury were exported from the ocean. Asian countries were important contributors of mercury export in the last decades and the western Pacific Ocean was identified as the main source. Estimates of per capita mercury exposure through fish consumption showed that populations in 38% of the 175 countries assessed, mainly insular and developing nations, were exposed to doses of methylmercury above governmental thresholds. Our study shows temporal trends and spatial patterns of Hg transport by fisheries. Given the high mercury intake through seafood consumption observed in several understudied yet vulnerable coastal communities, we recommend a comprehensive assessment of the health exposure risk of those populations.

Modulators of mercury risk to wildlife and humans in the context of rapid global change

Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like infectious disease incidence, which can affect Hg exposures and health outcomes. However, the success of global Hg-reduction efforts depends on accurate assessments of their effectiveness in reducing health risks. In this paper, we examine the role that key extrinsic and intrinsic drivers play on several aspects of Hg risk to humans and organisms in the environment. We do so within three key domains of ecological and human health risk. First, we examine how extrinsic global change drivers influence pathways of Hg bioaccumulation and biomagnification through food webs. Next, we describe how extrinsic socioeconomic drivers at a global scale, and intrinsic individual-level drivers, influence human Hg exposure. Finally, we address how the adverse health effects of Hg in humans and wildlife are modulated by a range of extrinsic and intrinsic drivers within the context of rapid global change. Incorporating components of these three domains into research and monitoring will facilitate a more holistic understanding of how ecological and societal drivers interact to influence Hg health risks.

Environmental and Body Concentrations of Heavy Metals at Sites Near and Distant from Industrial Complexes in Ulsan, Korea

BACKGROUND

Industrial pollution may affect the heavy metal body burden of people living near industrial complexes. We determined the average concentrations of atmospheric heavy metals in areas close to and distant from industrial complexes in Korea, and the body concentrations of these heavy metals in residents living near and distant from these facilities.

METHODS

The atmospheric data of heavy metals (lead and cadmium) were from the Regional Air Monitoring Network in Ulsan. We recruited 1,148 participants, 872 who lived near an industrial complex ("exposed" group) and 276 who lived distant from industrial complexes ("non-exposed" group), and measured their concentrations of blood lead, urinary cadmium, and urinary total mercury.

RESULTS

The results showed that atmospheric and human concentrations of heavy metals were higher in areas near industrial complexes. In addition, residents living near industrial complexes had higher individual and combined concentrations (cadmium + lead + mercury) of heavy metals.

CONCLUSION

We conclude that residents living near industrial complexes are exposed to high concentrations of heavy metals, and should be carefully monitored.

Decadal Changes in the Edible Supply of Seafood and Methylmercury Exposure in the United States

BACKGROUND

Methylmercury (MeHg) exposure is associated with adverse effects on neurodevelopment and cardiovascular health. Previous work indicates most MeHg is from marine fish sold in the commercial market, but does not fully resolve supply regions globally. This information is critical for linking changes in environmental MeHg levels to human exposure in the U.S. population.

OBJECTIVES

We used available data to estimate the geographic origins of seafood consumed in the United States (major ocean basins, coastal fisheries, aquaculture, freshwater) and how shifts in edible supply affected MeHg exposures between 2000-2002 and 2010-2012.

METHODS

Source regions for edible seafood and MeHg exposure in the United States were characterized from national and international landing, export and import data from the Food and Agricultural Organization of the United Nations and the U.S. National Marine Fisheries Service.

RESULTS

Our analysis suggests 37% of U.S. population-wide MeHg exposure is from mainly domestic coastal systems and 45% from open ocean ecosystems. We estimate that the Pacific Ocean alone supplies more than half of total MeHg exposure. Aquaculture and freshwater fisheries together account for an estimated 18% of total MeHg intake. Shifts in seafood types and supply regions between 2000-2002 and 2010-2012 reflect changes in consumer preferences (e.g., away from canned light meat tuna), global ecosystem shifts (e.g., northern migration of cod stocks), and increasing supply from aquaculture (e.g., shrimp and salmon).

CONCLUSION

Our findings indicate global actions that reduce anthropogenic Hg emissions will be beneficial for U.S. seafood consumers because open ocean ecosystems supply a large fraction of their MeHg exposure. However, our estimates suggest that domestic actions can provide the greatest benefit for coastal seafood consumers. https://doi.org/10.1289/EHP2644.

Toenail mercury Levels are associated with amyotrophic lateral sclerosis risk

INTRODUCTION

Mercury is a neurotoxic metal that is potentially a risk factor for amyotrophic lateral sclerosis (ALS). Consumption of methylmercury contaminated fish is the primary source of US population exposure to mercury.

METHODS

We used inductively coupled plasma mass spectrometry to measure levels of mercury in toenail samples from patients with ALS (n = 46) and from controls (n = 66) as a biomarker of mercury exposure.

RESULTS

Patients with ALS had higher toenail mercury levels (odds ratio 2.49, 95% confidence interval 1.18-5.80, P = 0.024) compared with controls, adjusted for age and sex. We also estimated the amount of mercury consumed from finfish and shellfish and found toenail mercury levels elevated overall among patients with ALS and controls in the top quartile for consumption (P = 0.018).

DISCUSSION

Biomarker data show that ALS is associated with increased with mercury levels, which were related to estimated methylmercury intake via fish. Replication of these associations in additional populations is warranted. Muscle Nerve, 2018.

Calls to Florida Poison Control Centers about mercury: Trends over 2003-2013

OBJECTIVE

The aim of this analysis was to contrast trends in exposure-report calls and informational queries (a measure of public interest) about mercury to the Florida Poison Control Centers over 2003-2013.

MATERIALS AND METHODS

Poison-control specialists coded calls to Florida Poison Control Centers by substance of concern, caller demographics, and whether the call pertained to an exposure event or was an informational query. For the present study, call records regarding mercury were de-identified and provided along with daily total number of calls for statistical analysis. We fit Poisson models using generalized estimating equations to summarize changes across years in counts of daily calls to Florida Poison Control Centers, adjusting for month. In a second stage of analysis, we further adjusted for the total number of calls each day. We also conducted analyses stratified by age of the exposed.

RESULTS

There was an overall decrease over 2003-2013 in the number of total calls about mercury [Ratio per year: 0.89, 95% CI: (0.88, 0.90)], and calls about mercury exposure [Ratio per year: 0.84, 95% CI: (0.83, 0.85)], but the number of informational queries about mercury increased over this time [Ratio per year: 1.15 (95% CI: 1.12, 1.18)]. After adjusting for the number of calls of that type each day (e.g., call volume), the associations remained similar: a ratio of 0.88 (95% CI: 0.87, 0.89) per year for total calls, 0.85 (0.83, 0.86) for exposure-related calls, and 1.17 (1.14, 1.21) for informational queries.

CONCLUSION

Although, the number of exposure-related calls decreased, informational queries increased over 2003-2013. This might suggest an increased public interest in mercury health risks despite a decrease in reported exposures over this time period.

Results of a national survey of high-frequency fish consumers in the United States

Exposure to contaminants in fish may be associated with adverse health outcomes even as fish consumption is generally considered beneficial. Risk assessments conducted to support regulatory analyses rely on quantitative fish consumption estimates. Here we report the results of a national survey of high-frequency fish consumers (n = 2099) based on a survey population statistically representative of ~17.6 million U.S. individuals consuming three or more fish meals per week. The survey was conducted during 2013 using an on-line survey instrument. Total fish consumption averaged 111g/day from market, restaurant and self-caught sources. Depending on the season, the incidence of individuals reporting consumption of self-caught species ranged between 10-12% of our high-frequency fish consuming demographic, averaging approximately 30g/day and comprising 23% of total fish consumption from all sources of fish. Recreational or self-caught consumption rates vary regionally and are poorly understood, particularly for high-frequency consumers, making it difficult to support national-scale assessments. A divergence between sport-fishing and harvesting of fish as a food-staple is apparent in survey results given differences in consumption patterns with income and education. Highest consumption rates were reported for low income respondents more likely to harvest fish as a food staple. By contrast, the incidence of self-caught fish consumption was higher with income and education although overall consumption rates were lower. Regional differences were evident, with respondents from the East-South Central and New England regions reporting lowest consumption rates from self-caught fish on the order of 12-16g/day and those from Mountain, Pacific and Mid-Atlantic regions reporting highest rates ranging from 44 to 59g/day. Respondent-specific consumption rates together with national-level data on fish tissue concentrations of PCBs, MeHg, and PFOS suggest that 10-58% of respondents reporting self-caught fish consumption are exposed to concentrations of these contaminants that exceed threshold levels for health effects based on a target hazard index of one, representing 2.3M to 19M individuals. The results of this nationwide survey of high-frequency fish consumers highlights regional and demographic differences in self-caught and total fish consumption useful for policy analysis with implications for distributional differences in potential health impacts in the context of both contaminant exposures as well as protective effects.

Mercury exposure, serum antinuclear antibodies, and serum cytokine levels in the Long Island Study of Seafood Consumption: A cross-sectional study in NY, USA

Mercury (Hg) is a well-known neurotoxin, and has been more recently studied specifically as an immunotoxin. In experimental and a few epidemiologic studies, Hg has been associated with distinct cytokine profiles and antinuclear antibody (ANA) positivity, though patterns at lower levels of exposure, typical of seafood consumers with a western diet, are not well characterized. Seafood consumers (n=287) recruited on Long Island, NY completed food frequency and health questionnaires and provided blood for analysis of Hg, poly-unsaturated fatty acids (omega-3 and omega-6 fatty acids), selenium (Se), ANA, and several cytokines (IL-1β, IL-4, IL-10, TNF-α, IL-17, IFN-γ, and IL-1ra). Logistic and linear regression analyses were conducted to evaluate associations between serum Hg and cytokines and ANA. Adjusted models accounted for gender, age, ethnicity, income, education, smoking, BMI, selenium, omega-3 fatty acids, omega-6 fatty acids, omega-6/omega-3 ratio, and fish intake. Sex-stratified models were also generated with the expectation that immune profiles would differ between women and men. Median blood Hg was 4.58µg/L with 90th %ile =19.8µg/L. Nine individuals displayed ANA positivity at serum titers above 1:80; many of the cytokines were below detection limits, and the ability to detect was used in the logistic regression analyses. In linear and logistic regression analyses, Hg was not significantly associated with any of the seven investigated cytokines or with ANA-positivity. Therefore, Hg was not associated with altered immune profiles in this population of seafood consumers.

Mercury in tunas and blue marlin in the North Pacific Ocean

Models and data from the North Pacific Ocean indicate that mercury concentrations in water and biota are increasing in response to (global or hemispheric) anthropogenic mercury releases. In the present study, we provide an updated record of mercury in yellowfin tuna (Thunnus albacares) caught near Hawaii that confirms an earlier conclusion that mercury concentrations in these fish are increasing at a rate similar to that observed in waters shallower than 1000 m. We also compiled and reanalyzed data from bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans) caught near Hawaii in the 1970s and 2000s. Increases in mercury concentrations in bigeye tuna are consistent with the trend found in yellowfin tuna, in both timing and magnitude. The data available for blue marlin do not allow for a fair comparison among years, because mercury concentrations differ between sexes for this species, and sex was identified (or reported) in only 3 of 7 studies. Also, mercury concentrations in blue marlin may be insensitive to modest changes in mercury exposure, because this species appears to have the ability to detoxify mercury. The North Pacific Ocean is a region of both relatively high rates of atmospheric mercury deposition and capture fisheries production. Other data sets that allow temporal comparisons in mercury concentrations, such as pacific cod (Gadus macrocephalus) in Alaskan waters and albacore tuna (Thunnus alalunga) off the US Pacific coast, should be explored further, to aid in understanding human health and ecological risks and to develop additional baseline knowledge for assessing changes in a region expected to respond strongly to reductions in anthropogenic mercury emissions. Environ Toxicol Chem 2017;36:1365-1374. © 2017 SETAC.

National estimation of seafood consumption in Mexico: Implications for exposure to methylmercury and polyunsaturated fatty acids

BACKGROUND

Seafood is a good source of Omega-3 polyunsaturated fatty acids (ω3-PUFA) but also contains the toxic contaminant methylmercury (MeHg). National estimates of exposure to both compounds through seafood intake in Mexico are not known. The objective of the current study was to describe national seafood consumption habits and to estimate seafood-based exposure to ω3-PUFAs and MeHg.

METHODS

We analyzed data from a 24-h dietary recall extracted from the 2012 National Health and Nutrition Survey of Mexico (n = 10,096 subjects aged 1y and older). National per capita seafood intake as well as information on age, sex, socioeconomic status, and geographic region was obtained. The contribution of each seafood item to the total MeHg exposure was estimated, as was the balance between estimated exposures to ω3-PUFAs and MeHg.

RESULTS

A mean daily seafood intake of 10 g/day was estimated. The top species consumed in decreasing order were: canned tuna, sunfish, shrimp, mullet, carp and schoolshark (constituted 60% of seafood intake). Canned tuna and schoolshark contributed 75% of the population's estimated exposure to MeHg. The best balance of population-level exposures to ω3-PUFAs and MeHg was found in salmon, sardine, trout and anchovies.

CONCLUSION

Environmental dietary exposure to MeHg is a public health concern and thus a good understanding of seafood consumption is needed to create national consumption guidelines. The current study provides nationally-representative data in Mexico from which decisions can be made (e.g., UN Minamata Convention) and future studies conducted.

Factors associated with mercury levels in human placenta and the relationship to neonatal anthropometry in Jamaica and Trinidad & Tobago

The aim of this study was to investigate the mercury levels in human placenta and its relationship to neonatal anthropometry for a group of selected pregnant women in Kingston and Manchester in Jamaica and St. Joseph in Trinidad & Tobago. The participants were interviewed on their fish intake. Neonatal anthropometric data were also recorded. The placental mercury concentrations ranged from 0.64±0.5μg/kg to 1.4±0.6μg/kg. The most significant associated factor for prenatal mercury exposure was maternal fish intake. Those pregnant women who regularly ate shark recorded the highest placenta mercury concentrations. Their neonates also had slightly smaller mean head circumference and lower birth weight. The mean placental mercury concentrations in this study were found to be lower than the literature values. Therefore it was difficult to detect any significant changes in neonatal anthropometry. This type of study can contribute to the extent of mercury exposure in the region.

Scientific foundations of fish-consumption advice for pregnant women: Epidemiological evidence, benefit-risk modeling, and an integrated approach

BACKGROUND

Pregnant women need fish consumption advice that increases seafood intake and simultaneously reduces methylmercury (MeHg) exposure. Two disciplines, epidemiology and benefit-risk modeling, can support such advice. Some current models suggest that fish consumption during pregnancy has only net beneficial effects. In contrast, many recent epidemiological studies have associated adverse effects on cognitive development with ordinary fish intake and MeHg doses routinely encountered by up to one in six US women of childbearing age. Proposed federal fish-consumption advice is based solely on a benefit-risk model. A more complete assessment integrating both types of evidence is needed.

OBJECTIVES AND METHODS

The goal of this paper is to use a model to rank seafood items by their relative benefits and risks, producing consumer seafood choice recommendations that are also consistent with epidemiological observations. Recent epidemiological studies and benefit-risk models are reviewed, and model results are compared with one another and with epidemiological observations to identify commonalities that support inter-calibration.

RESULTS AND CONCLUSIONS

Both approaches quantify MeHg doses at which harm slightly exceeds benefit. A model from the US Food and Drug Administration (FDA) predicts adverse effects at fish intakes containing, on average, more than 16 times the the US Reference Dose (RfD) for MeHg. Epidemiological results indicate that the RfD itself approximates a minimal adverse dose. This conceptual similarity allows FDA's model to be calibrated with the epidemiological results to generate fish intake recommendations that both the model and the epidemiology suggest should have substantially positive public health impacts.

Declining Mercury Concentrations in Bluefin Tuna Reflect Reduced Emissions to the North Atlantic Ocean

Tunas are apex predators in marine food webs that can accumulate mercury (Hg) to high concentrations and provide more Hg (∼40%) to the U.S population than any other source. We measured Hg concentrations in 1292 Atlantic bluefin tuna (ABFT, Thunnus thynnus) captured in the Northwest Atlantic from 2004 to 2012. ABFT Hg concentrations and variability increased nonlinearly with length, weight, and age, ranging from 0.25 to 3.15 mg kg^-1, and declined significantly at a rate of 0.018 ± 0.003 mg kg^-1 per year or 19% over an 8-year period from the 1990s to the early 2000s. Notably, this decrease parallels comparably reduced anthropogenic Hg emission rates in North America and North Atlantic atmospheric Hg⁰ concentrations during this period, suggesting that recent efforts to decrease atmospheric Hg loading have rapidly propagated up marine food webs to a commercially important species. This is the first evidence to suggest that emission reduction efforts have resulted in lower Hg concentrations in large, long-lived fish.

Assessment of fish consumption and mercury exposure among pregnant women in Jamaica and Trinidad & Tobago

BACKGROUND

Fish is an essential and traditional element in the diet of most Caribbean people. However it also contains methylmercury which can have severe effects on fetal neurodevelopment. The objective of this study was to assess the fish intake of a selected group of pregnant women from Jamaica and Trinidad & Tobago and evaluate prenatal mercury exposure, using the placenta as a biomarker.

METHOD

Food frequency questionnaires and placental samples were obtained from participating parturients at the time of delivery at the University Hospital of the West Indies in Kingston, Jamaica (N = 100, from November 2012 to March 2013) and the Mt Hope Women's hospital in St Joseph, Trinidad & Tobago (N = 30, in June 2015). The participants were asked to identify the species of fish and the frequency of consumption. Placental samples were analysed for mercury using cold vapour atomic absorption.

RESULTS

The fish consumption preferences for pregnant women, varies based on the marine fish catch production of each country. The main fish species that contributed to the highest estimated methylmercury exposure in Jamaica and Trinidad & Tobago were cod and shark, respectively. There was a weak association between maternal fish intake and placental mercury concentrations. The mean placental mercury concentrations in Jamaica and Trinidad & Tobago were 0.74 ± 0.5 μg/kg and 1.46 ± 0.6 μg/kg, wet weight respectively.

CONCLUSION

The results from this study showed an influence of Caribbean fish intake preferences on mercury exposure and thus a recommendation for continuous bio-monitoring for public health purposes.

Mercury, eicosapentanoic acid and docosahexaenoic acid demonstrate limited effect on plasma paraoxonase-1 activity and blood pressure among avid seafood consumers in the Long Island Study of Seafood Consumption, NY, USA

BACKGROUND AND AIM

Moderate fish consumption is recommended for prevention of coronary heart disease (CHD) as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have known beneficial effects on risk factors such as reducing blood pressure (BP) and increasing paraoxonase-1 (PON-1) activity. However concomitant methylmercury (MeHg) exposure from fish consumption may mitigate these benefits and the net effect on BP and PON-1 activity has not been extensively studied in western populations consuming diverse seafood types. We studied the correlation between EPA, DHA and Hg levels with BP and PON-1 activity in a population of avid seafood consumers.

METHODS

Two hundred and eighty-eight avid seafood consumers from Long Island, NY had blood samples drawn for total blood mercury (THg), plasma EPA and DHA levels, and plasma PON-1 activity. Average systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP) were measured.

RESULTS

Subjects' mean EPA+DHA was 4.9% total fatty acids, mean THg was 7.6mcg/L. Mean SBP was 122.5mmHg, mean DBP 70.3mmHg, mean PP 52.2mmHg and mean PON-1 activity 421.2U/L. THg was not associated with any of the BP measures in adjusted linear regression models; EPA+DHA was significantly inversely associated with PP (p=0.02). THg was associated with a significant increase in PON-1 activity (p=0.04), while EPA+DHA was associated with a significant decrease in PON-1 activity (p=0.007); although the size of the effects was small.

CONCLUSIONS

Our findings suggest blood THg and serum DHA+EPA levels have limited relationship to BP and PON-1 activity, and may not be important modulators of these known CHD risk factors in this population of avid seafood consumers.

Comparing nearshore benthic and pelagic prey as mercury sources to lake fish: the importance of prey quality and mercury content

Mercury (Hg) bioaccumulation in fish poses well-known health risks to wildlife and humans through fish consumption. Yet fish Hg concentrations are highly variable, and key factors driving this variability remain unclear. One little studied source of variation is the influence of habitat-specific feeding on Hg accumulation in lake fish. However, this is likely important because most lake fish feed in multiple habitats during their lives, and the Hg and caloric content of prey from different habitats can differ. This study used a three-pronged approach to investigate the extent to which habitat-specific prey determine differences in Hg bioaccumulation in fish. This study first compared Hg concentrations in common nearshore benthic invertebrates and pelagic zooplankton across five lakes and over the summer season in one lake, and found that pelagic zooplankton generally had higher Hg concentrations than most benthic taxa across lakes, and over a season in one lake. Second, using a bioenergetics model, the effects of prey caloric content from habitat-specific diets on fish growth and Hg accumulation were calculated. This model predicted that the consumption of benthic prey results in lower fish Hg concentrations due to higher prey caloric content and growth dilution (high weight gain relative to Hg from food), in addition to lower prey Hg levels. Third, using data from the literature, links between fish Hg content and the degree of benthivory, were examined, and showed that benthivory was associated with reduced Hg concentrations in lake fish. Taken together, these findings support the hypothesis that higher Hg content and lower caloric content make pelagic zooplankton prey greater sources of Hg for fish than nearshore benthic prey in lakes. Hence, habitat-specific foraging is likely to be a strong driver of variation in Hg levels within and between fish species.

Fish Consumption and Hair Mercury Among Asians in Chicago

OBJECTIVES

The aim of the study was to characterize the risk for elevated mercury (Hg) from fish consumption among Asians in Chicago. Consumption of fish contaminated with methyl Hg (MeHg) can affect the neurodevelopment in children and cardiovascular disease risk in adults.

METHODS

We collected fish consumption information and hair samples for Hg at two health fairs. We purchased fish from Asian fish markets.

RESULTS

Geometric mean hair Hg from 71 participants was 0.58  μg/g, with 28% overall and 29% of women of childbearing age having hair Hg levels at least 1  μg/g; 20% ate fish 4 or more times/wk. Tuna consumption and non-Chinese Asian ethnicity were associated with elevated Hg. Hg levels in purchased fish were generally low.

CONCLUSIONS

Our study confirms other findings that, compared with estimates of the general US population, Asians are at higher risk of elevated MeHg because of frequent fish consumption.