Methylmercury exposure assessment using dietary and biomarker data among frequent seafood consumers in France CALIPSO study

Characterizing the risk related to the exposure to methylmercury over a lifetime: A global approach using population internal exposure

Seafood products accumulate methylmercury throughout the food chain and are the main source of methylmercury exposure. Methylmercury may trigger a number of adverse health effects, such as neurodevelopmental or nephrotoxic effects, the risk of which cannot be ruled out for the French high consumers of seafood. The characterisation of methylmercury-related risks is generally based on short-term dietary exposure without considering changes in consumption and exposure over the lifetime. Additionally, focusing on short-term dietary exposure, the fate of methylmercury (especially its accumulation) in the organism is not considered. The present study proposes a methodology basing risk characterization on estimates of body burden over a lifetime. First, trajectories of dietary exposures throughout lifetime were constructed based on the actual concentrations of total diet studies for a fictive representative French population, taking into account the social, economic and demographic parameters of individuals. Next, the fate of methylmercury in the body was estimated, based on these trajectories, using a specific physiologically-based kinetic (PBK) model that generated a representative pool of body burden trajectories. Simulated hair mercury concentrations were closed to previously reported French representative human biomonitoring data. Results showed that at certain stages of life, concentrations of methylmercury in hair were higher than the human biomonitoring guidance value set at 2.5 μg/g of hair by JECFA. This study showed the added value, in the case of substances accumulating in the body, of estimating dietary exposure over a lifetime and using exposure biomarkers estimated by a PBK model characterize the risk.

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.

Consumption of Bivalve Shellfish in French Coastal Populations: Data for Acute and Chronic Exposure Assessment

Shellfish are a source of nutrients but are also a matter of concern in terms of food safety due to natural contaminants such as phycotoxins or anthropogenic contaminants including microbial agents and heavy metals. However, data related to consumption for each mollusk species are scarce and missing for appropriate exposure calculation. The objective of the study was to generate shellfish consumption data in the adult coastal population in France to assess exposure to health risks, the effects of determinants on the frequency of consumption and usual intake, and shellfish food risk perception. Our study, named the CONSOMER study, was carried out using an online survey in 2016 and 2017 and included a food frequency questionnaire. After validation, 2,479 individual questionnaires were available for statistical analysis. Our findings provide estimates of shellfish consumption frequency, portion sizes, weekly intake in g/week, and g/week/body weight that can be used for acute and chronic exposure calculations. For the acute risk, the 97.5th percentile of the portion size was found to be around 290 g for the adult coastal population. For chronic exposure, recreational shellfish harvesting activities were associated with higher weekly intakes. A non-negligible part of this subpopulation is not aware of food safety recommendations concerning harvesting areas. Results for shellfish harvester consumption in particular are consistent with other available data. Exposure calculations and safety recommendations should target shellfish harvesters.

Dietary exposure assessment of methylmercury and polyunsaturated fatty acids in saltwater fish and processed foods among Taiwanese women of child-bearing age and children: A novel core food-matching approach

Saltwater fish is rich in health-promoting polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Excessive fish intake may also cause health hazards due to methylmercury (MeHg). A novel dose estimation method was proposed in this study to improve the quality of food matching by considering the usage ratio of cooking and processing methods in sampling design. In total, 39 table-ready samples were specified according to 2-3 common cooking methods, and MeHg and total mercury (THg) were analyzed. The results showed that mercury was detected in 20 samples (LOD = 0.01 μg/g). High MeHg samples included fried-Spanish mackerel (1.23 μg/g), non-cooked shredded swordfish (0.325 μg/g), pan-fried Spanish mackerel (0.248 μg/g), and non-cooked shredded salmon (0.208 μg/g). Consumption data (n = 166,911) were obtained from 24-h recalls in the 2005-2008 Nutrition and Health Surveys in Taiwan (NAHSIT). The average whole-group estimated daily intake (EDI_WG) was 0.018 (7.9% tolerable daily intake, TDI) for women of child-bearing age and 0.031 μg/day per kg body weight (13.6% TDI) for children. However, 95th percentile values (P95) of 90.4% TDI and 185% TDI were estimated for the two consumer-only populations, which have raised public health concerns. The ratio of % TDI to % daily reference intake (% DRI) was used as a risk-benefit (R/B) indicator. The top 4 R/B foods were: tuna sashimi (0.089 and 0.14), non-cooked shredded swordfish (0.033 and 0.052), fried-Spanish mackerel (0.027 and 0.043) and deep-fried fish balls (0.022 and 0.035) in the two perspective populations.

Effects of seafood consumption on mercury exposure in Norwegian pregnant women: A randomized controlled trial

BACKGROUND

Seafood provides nutrients that are important for optimal development of the unborn child. However, seafood is also a source of contaminants including mercury (Hg) and methylmercury (MeHg) that may have adverse effects on neurodevelopment of the fetus. Humans are predominantly exposed to MeHg through seafood consumption, however, levels of MeHg vary considerably between species.

OBJECTIVES

Investigate, in a randomized controlled trial (RCT) during pregnancy, if an increased intake of Atlantic cod (Gadus morhua), a fish species with relatively low levels of MeHg contamination, influences total hair Hg (THHg) concentrations in humans.

METHODS

Pregnant women (n = 137) were enrolled in the RCT "Mommy's Food" (2016-2017), which was designed to increase iodine status. Participants were randomly assigned to intervention (400 g of cod fillets per week) or control (continued habitual diet) groups for 16 weeks (gestational week 20-36). THHg concentrations were measured at baseline and post-intervention using thermal decomposition, amalgamation, and atomic absorption spectrophotometry (US EPA method 7473). The trial is registered in ClinicalTrials.gov, NCT02610959.

RESULTS

Post-intervention, the intervention group had median (inter-quartile range) THHg concentrations of 554 (392-805) µg/kg, and the control group 485 (341-740) µg/kg (p = 0.186). When adjusting for baseline THHg concentrations, there was a significant difference between the groups in those participants with baseline THHg concentrations below 534 µg/kg. Post-intervention, 8% of the study population exceeded the US EPA reference dose in hair (1,000 µg/kg) (intervention group: n = 6, control group: n = 4).

CONCLUSION

THHg concentrations were generally low in both study groups of pregnant women, despite the relatively high seafood intake. While the intervention with 400 g of cod per week slightly increased THHg concentrations, it did not lead to an increase in number of subjects exceeding the US EPA reference dose; a dose level at which no adverse effects are expected to occur over a period of lifetime exposure.

Concentration of mercury species in hair, blood and urine of individuals occupationally exposed to gaseous elemental mercury in Asturias (Spain) and its comparison with individuals from a control group formed by close relatives

Between November 19th, 2012 and December 3rd, 2012, 50 workers were intoxicated with gaseous Hg in San Juan de Nieva (Asturias, Spain) during the maintenance of a heat exchanger of a zinc manufacturer. We have quantified the concentration of methylmercury (MeHg), ethylmercury (EtHg) and Hg(II) in blood, hair and urine samples of those individuals taken three years after the accident. Blood, hair and urine of their closest relatives were also analyzed to assess whether the mercury burden present in the intoxicated individuals was due to the occupational exposure or to environmental or lifestyle-related factors. The determination of the mercury species in the samples was carried out applying multiple spiking Isotope Dilution GC-ICP-MS. This procedure corrects for possible interconversion reactions between the Hg species during the sample preparation procedure. Linear correlations were observed for both groups when plotting MeHg in blood vs MeHg in hair, and MeHg in hair vs Hg (II) in urine. The concentrations of Hg species in the intoxicated individuals were not significantly different from those obtained in the control group except for MeHg in blood. Significantly higher levels of MeHg in blood were obtained in some of the intoxicated individuals who had not consumed fish or seafood since the accident. A different correlation between MeHg in hair and MeHg in blood was obtained for these individuals compared to the control group who showed a hair-to-blood ratio consistent with the reported value for people exposed to Hg via fish consumption. Our results suggest that ingested MeHg followed the same pathway of deposition in hair in exposed and non-exposed individuals. However, the exposed individuals with high MeHg levels in blood showed a significantly different extent of MeHg deposition in hair compared to the control group.

Risk tradeoffs associated with traditional food advisories for Labrador Inuit

The traditional Inuit diet includes wild birds, fish and marine mammals, which can contain high concentrations of the neurotoxicant methylmercury (MeHg). Hydroelectric development may increase MeHg concentrations in traditional foods. Consumption advisories are often used to mitigate such risks and can result in reduced intake of traditional foods. Data from a dietary survey, MeHg exposure assessment and risk analysis for individuals in three Inuit communities in Labrador, Canada (n = 1145) in 2014 indicate reducing traditional food intake is likely to exacerbate deficiencies in n-3 polyunsaturated fatty acids and vitamins B12 and B2. Traditional foods accounted for < 5% of per-capita calories but up to 70% of nutrients consumed. Although consumption advisories could lower neurodevelopmental risks associated with an increase in MeHg exposure (90th-percentile ∆IQ = - 0.12 vs. - 0.34), they may lead to greater risks of cardiovascular mortality (90th-percentile increase: + 58% to + 116% vs. + 25%) and cancer mortality (90th-percentile increase + 2% to + 4% vs. no increase). Conversely, greater consumption of locally caught salmon mostly unaffected by hydroelectric flooding would lower all these risks (90th-percentile ∆IQ = + 0.4; cardiovascular risk: - 45%; cancer risk: - 1.4%). We thus conclude that continued consumption of traditional foods is essential for Inuit health in these communities.

A likely placental barrier against methylmercury in pregnant rats exposed to fish-containing diets

Methylmercury (MeHg) taken up through fish consumption can be transferred from the mother to the fetus during pregnancy. In the present study, pregnant rat mothers were contaminated with environmentally relevant doses of 36 and 76 ng MeHg/g of food using diets containing naturally mercury-containing fish. Young female rats fed with fish-containing food after weaning showed decreased locomotion in Y maze for accumulated concentrations in brain as low as 75 ng Hg/g dry weight (15 ng Hg/g wet weight). Young female rats fed the control diet after weaning yet borne by mothers fed the diet containing 76 ng MeHg/g, presented a 58% reduced activity in the open-field labyrinth, meaning that the maternal exposure to fish-containing food exerted an effect in utero that lasted several weeks after birth. Newborns were protected against Hg exposure by the placental barrier since in newborns from mothers fed the diet containing 76 ng MeHg/g of food, the concentrations of Hg in brain, kidney, liver and skeletal muscles represented 12, 3, 21 and 18% of those of their mother's tissues, respectively. These results suggest the existence, at least in rats, of a threshold level in terms of MeHg exposure above which the placental barrier collapses.

Quantitative estimation of mercury intake by toxicokinetic modelling based on total mercury levels in humans

Mercury is a toxic metal that can be disseminated into the environment from both natural and anthropogenic sources. Human exposure to the metal stems mainly from food, and more particularly from the consumption of fish and other seafoods. Examining dietary exposure and measuring mercury levels in body tissues are two ways of estimating exposure to mercury. In this study, we utilized a modelling system consisting of three linear toxicokinetic models for describing the fate of methyl mercury, inorganic mercury, and metallic mercury in the body, in order to estimate daily intake of mercury as measured through total mercury concentrations in the blood. We then compared the results stemming from our modelling system to those of the detailed semi-quantitative food frequency questionnaire (FFQ) of the Norwegian Fish and Game (NFG) Study, a project that focused on dietary mercury exposure. The results indicate that toxicokinetic modelling based on blood levels gave higher daily intake values of mercury compared to those of the FFQ. Furthermore, the former had a wider range of estimates than the latter. The properties of the toxicokinetic model or limitations in the dietary exposure assessment could be posited as reasons for the differences between the respective methods. Moreover, the results may have been influenced by sources of mercury exposure that cannot be described as dietary, such as amalgam fillings.

Determination of Mercury Daily Intake and Hair-to-Blood Mercury Concentration Ratio in People Resident of the Coast of the Persian Gulf, Iran

The objectives of this study were to understand the mercury daily intake and hair-to-blood mercury ratio in fishermen and non-fishermen families in the coast of the Persian Gulf in Iran. The mean mercury concentration in the hair of fishermen and non-fishermen families was 5.76 and 2.27 μg/g, respectively. The mean mercury concentrations of RBCs were obtained for fishermen families and non-fishermen families: 35.96 and 17.18 μg/L, respectively. Hair mercury concentrations in 17% of people were higher than 10 μg/g, the No Observed Adverse Effects Level set by the World Health Organization. 78% of people had a blood mercury value > 5.8 μg/L, the standard level set by the U.S. Environmental Protection Agency. A significant correlation (r = 0.94, p = 0.000) was seen between log hair and RBCs mercury concentrations. The mean mercury daily intake for fishermen and non-fishermen families was 0.42 and 0.20 µg/kg BW per day, respectively. The mean mercury daily intake of fishermen families was higher than the provisional tolerable daily intake (0.23 µg/kg BW per day) suggested by the Joint Expert Committee on Food Additives. Mercury daily intake significantly correlated with fish consumption (r = 0.50, p = 0.000) and log hair mercury (r = 0.88, p = 0.000). The total mean of hair-to-blood mercury concentration ratio was 306. We conclude that the use of mercury concentrations in the hair and RBCs could have been suitable biomarkers for predicting mercury exposure of people with a high rate of fish consumption.

[Socioeconomic status, eating patterns, and heavy metals exposure in women of childbearing age in Cali, Colombia]

INTRODUCTION

Global increase in food and water pollution is associated with health risk, which depends on the concentration, the dose, and the exposure time. This has raised concerns about the possible long-term effects of chronic exposure to low concentrations of heavy metals, such as lead, cadmium and mercury.

OBJECTIVE

To explore the relationship among socioeconomic status, eating patterns, and exposure to heavy metals among a population of women in Cali, Colombia.

MATERIALS AND METHODS

A total of 233 non-pregnant women of childbearing age living in the Aguablanca district of Cali, Colombia, were enrolled in the study. We gathered sociodemographic data, as well as information on housing conditions, exposure to heavy metals, frequency of food intake, and anthropometric measurements. Samples of lettuce, cabbage and fish (tilapia and butterfish) were collected to determine lead, cadmium, and mercury concentrations. Descriptive and multiple correspondence analyses were performed to establish eating patterns.

RESULTS

Fish was served in each of the three main meals of the day, with a bigger serving at lunch time. Cadmium was found in three samples of butterfish at levels below the acceptable. Of those who ate fish more than once a week, 11.1% bought the product at a cadmium-positive store. The multiple correspondence analysis showed a positive relationship between being black and consuming butterfish and tilapia more than once per week.

CONCLUSIONS

The findings showed that the studied population had access to heavy metal-contaminated food, which combined with the women's cultural eating patterns, socioeconomic status, and metabolic characteristics led to a greater vulnerability to the effects of heavy metals exposure.

Mercurial exposure of residents of Santarém and Oriximiná cities (Pará, Brazil) through fish consumption

A survey of the mercurial exposure of residents of Santarém and Oriximiná showed a differential mercurial impregnation between men and women. At the level of both cities, the mean hair mercury concentrations were 1.5 ± 0.5 (90th and 95th percentiles: 2.8 and 4.3) and 2.52 ± 0.09 μg g Hg/g (90th and 95th percentiles: 4.7 and 8.1) for women and men, respectively. The mercurial contamination appeared significantly closely linked to the daily amount of consumed fish. Carnivore species pescada branca (Plagioscion squamosissimus) and apapá (Pellona castelnaeana) and non-carnivore species pacú (Mylossoma duriventre) and aracú (Schizodon fasciatus) were consumed by 22, 19, 55 and 25% of people, respectively, and the mean mercury concentrations within fish flesh were 1.44 ± 0.11, 1.66 ± 0.19, 0.48 ± 0.09 and 0.49 ± 0.06 μg/g dry weight, respectively. Men aged above 35 were significantly more contaminated than those below. The mean hair concentrations of men were 5.20 ± 1.25 and 1.50 ± 0.22 μg/g, for those aged above 35 and below, respectively. The probability for women of childbearing age from both cities to present a hair mercury concentration above 1 μg Hg/g (corresponding to the US Environmental Protection Agency reference dose) was equal to 0.30 (95% confidence interval of 0.24-0.36). The probability of hair mercury concentration to be above the lowest observable adverse effect level (LOAEL) (0.3 μg Hg/g) was equal to 0.79 (95% confidence interval: 0.73-0.86).

Prenatal mercury exposure, autism, and developmental delay, using pharmacokinetic combination of newborn blood concentrations and questionnaire data: a case control study

BACKGROUND

Methylmercury (MeHg), known for well over a century as a neurotoxin in adults, has more recently been studied for potential detrimental effects during early brain development. While several studies have estimated mercury exposure, they usually rely on either a single biomarker or questionnaire data, each of which has limitations. The goal of this paper was to develop a toxicokinetic model that incorporates both biomarker and questionnaire data to estimate the cumulative exposure to MeHg through seafood consumption using data collected from the Childhood Autism Risks from Genetics and the Environment (CHARGE) study.

METHODS

We utilized a previously described discrete-time model that estimates blood MeHg concentration given a piecewise-constant ingestion rate and single-compartment pharmacokinetics. We measured newborn bloodspot Hg concentrations and obtained information pertaining to maternal fish consumption using a questionnaire. Using MeHg concentration estimates from the toxicokinetic model, cumulative MeHg exposure was estimated in children with autism, children with developmental delay, and typically developing children. Median estimated cumulative MeHg was compared among diagnostic groups using the Kruskal-Wallis Test. Multinomial logistic regression models were constructed to assess the association between cumulative MeHg concentration and the risk of autism and developmental delay (vs. typical development).

RESULTS

The estimated average MeHg concentration of for all fish species consumed by mothers was 42 ppb. Median cumulative MeHg over gestation was similar across diagnostic groups (p-values raged from 0.91 to 0.98). After adjusting for potential confounding, we found no association between cumulative MeHg exposure and the risk of autism (OR = 0.95, 95% CI: 0.95, 1.12) or developmental delay (OR = 1.00, 95% CI: 0.89, 1.13).

CONCLUSIONS

The toxicokinetic model described in this paper yielded fish MeHg concentration estimates that are consistent with fish species containing lower levels of MeHg. Overall, cumulative MeHg exposure does not appear to detectably elevate the risk of autism or developmental delay. Based on the regression standard error for the association between ASD and TD, we would have reported statistical significance for an adjusted odds ratio of 1.09 or larger. This method can easily be extended to other epidemiologic studies in which there is a biomarker measurement and questionnaire data regarding exposure.

Relationship between dietary mercury intake and blood mercury level in Korea

This study was performed to evaluate the effect of dietary factors for mercury exposure by comparing with blood mercury concentration. Study population consisted of 1,866 adults (839 men and 1,027 women) in randomly-selected 30 districts in southeast Korea. Dietary mercury intake was calculated from food frequency questionnaire (FFQ) on seafood items and 24 hr recall record. Blood mercury concentration was measured with atomic absorption spectrometry. Mean age of the subjects was 43.5 ± 14.6 yr. The FFQ showed that mercury-laden fish (tuna, shark) and frequently-eating fish (squid, belt fish, mackerel) were important in mercury intake from fish species. The recall record suggested that fish and shellfish was a highest group (63.1%) of mercury intake and had a wide distribution in the food groups. In comparison with the blood mercury concentration, age group, sex, household income, education, drinking status and coastal area were statistically significant (P < 0.001). In multiple regression analysis, coefficient from the FFQ (β = 0.003) had greater effect on the blood mercury than the recall record (β = 0.002), but the effect was restricted (adjusted R(2) = 0.234). Further studies with more precise estimation of dietary mercury intake were required to evaluate the risk for mercury exposure by foods and assure risk communication with heavily-exposed group.

Plasma mercury levels in Hong Kong residents: in relation to fish consumption

Mercury exposure is of particular concern since mercury is a neurotoxin and the developing fetus is most sensitive to its adverse effect. Human blood is routinely used as an indicator for the evaluation of human exposure to Hg. To investigate Hg species in human plasma for Hong Kong residents and the relationship between fish consumption and Hg species in plasma, 151 plasma samples were analyzed for Hg species. The mean values of total Hg (THg) and methyl-mercury (MeHg) concentration in plasma were 0.62 and 0.28 μg/L, respectively. No significant differences were observed between females and males as well as among age groups. Fish consumption rate was significantly positively correlated with MeHg concentrations in plasma, which demonstrated that plasma could be a biomarker for human MeHg exposure. Two methods were used to estimate human MeHg exposure. One was based on fish MeHg content and fish consumption rate (EDI(Fish)), another was employed by converting MeHg concentration in blood to MeHg exposure amount (EDI(Blood)). A significant positive correlation was observed between EDI(Blood) and EDI(Fish), and no significant difference was found between EDI(Blood) and EDI(Fish). These results demonstrated that fish consumption was the major source of MeHg for humans.

Dietary mercury exposure in a population with a wide range of fish consumption--self-capture of fish and regional differences are important determinants of mercury in blood

Human, low level, chronic exposure to mercury (Hg) from fish is of concern because of potential neurodevelopmental and cardiovascular toxicity. The purpose of the study was to 1) measure total mercury (THg) in blood and estimate dietary exposure in a population group with a wide range of seafood consumption, 2) assess the intake and blood concentration in relation to tolerable intake values, 3) characterise dietary sources, and 4) to investigate the relationship between dietary THg with THg in blood (BTHg), including factors that can explain the variance in BTHg concentrations. The participants (n=184) filled in an extensive food frequency questionnaire which was combined with a database on THg concentrations in Norwegian food, and donated blood and urine. Median consumption of seafood was 65 g/day (range 4 to 341 g/day). The calculated mean dietary THg exposure was 0.35 (median 0.30) μg/kg body weight/week. Seafood contributed on average 95% to the exposure. The JECFA Provisional Tolerable Weekly Intake (PTWI) of 1.6 μg MeHg/kg bw/week was not exceeded by any of the participants. BTHg ranged from 0.6 to 30 μg/L, with a mean of 5.3 (median 4.0 μg/L). There was a strong relationship between total seafood consumption and BTHg concentrations (r=0.58 95%CI: 0.48, 0.67) and between estimated THg dietary exposure and BTHg (r=0.46 95%CI: 0.35, 0.57). Fish consumption, sex, catching >50% of their seafood themselves, and living in coastal municipalities were significant factors in linear regression models with lnBTHg. Including urinary Hg in the regression model increased the explained variance from 54% to 65%. In a toxicokinetic model, the calculated dietary intake appeared to moderately underestimate the measured BTHg among the participants with the highest BTHg. Only two of the participants had BTHg slightly above a value equivalent to the JECFA PTWI, but none of them were women in fertile age.

The relationship between the fish consumption and blood total/methyl-mercury concentration of costal area in Korea

The purpose of this study was to evaluate the relationship between fish consumption and blood THg/MeHg concentration in Korean adults by measuring MeHg concentration in blood directly. The study subjects consisted of 400 adults aged 20 or older from 30 subareas in Busan, Ulsan and Gyeongsangnam-do province in Korea from August to October, 2010. We tried to recruit the same number of male and female participants in different age groups (20s, 30s, 40s, 50s and 60s) and allocated 13-16 subjects by district to represent Hg concentration in the research areas. The geometric means of THg and MeHg concentration in blood were 5.27 μg/L (5.00-5.57) and 4.05 μg/L (3.81-4.32), respectively. The proportion of MeHg/THg concentration was 78.53% (77.09-79.97). MeHg concentration was higher in coastal areas (4.26 μg/L) than in inland areas (3.52 μg/L) and was higher in men (4.68 μg/L) than in women (3.52 μg/L). In male participants, blood MeHg concentration increased with increasing annual fish consumption, and the proportion of MeHg/THg concentration showed an upward trend as THg concentration increased. However, none of the measures of the proportion of MeHg/THg showed significant differences. This is the first report in Korea about the relationship between blood MeHg concentration and related factors. Our findings suggest that MeHg concentration is affected by fish consumption as well as by gender difference and drinking status. Since the pathological mechanism has not been clarified, additional studies are needed for explaining the biological and lifestyle differences in the risk of adverse health effects by Hg exposure.

A restricted cubic spline approach to assess the association between high fat fish intake and red blood cell EPA + DHA content

BACKGROUND AND AIMS

Fish, especially fatty fish, are the main contributor to eicosapentaenoic (EPA) and docosahexaenoic (DHA) intake. EPA and DHA concentrations in red blood cells (RBC) has been proposed as a cardiovascular risk factor, with <4% and >8% associated with the lowest and greatest protection, respectively. The relationship between high fat fish (HFF) intake and RBC EPA + DHA content has been little investigated on a wide range of fish intake, and may be non-linear. We aimed to study the shape of this relationship among high seafood consumers.

METHODS AND RESULTS

Seafood consumption records and blood were collected from 384 French heavy seafood consumers and EPA and DHA were measured in RBC. A multivariate linear regression was performed using restricted cubic splines to consider potential non-linear associations. Thirty-six percent of subjects had an RBC EPA + DHA content lower than 4% and only 5% exceeded 8%. HFF consumption was significantly associated with RBC EPA + DHA content (P [overall association] = 0.021) adjusted for sex, tobacco status, study area, socioeconomic status, age, alcohol, other seafood, meat, and meat product intakes. This relationship was non-linear: for intakes higher than 200 g/wk, EPA + DHA content tended to stagnate. Tobacco status and fish contaminants were negatively associated with RBC EPA + DHA content.

CONCLUSION

Because of the saturation for high intakes, and accounting for the concern with exposure to trace element contaminants, intake not exceeding 200 g should be considered.

Methyl mercury exposure from fish consumption in vulnerable racial/ethnic populations: probabilistic SHEDS-Dietary model analyses using 1999-2006 NHANES and 1990-2002 TDS data

NHANES subjects self-identified as "Asian, Pacific Islander, Native American, or multiracial" (A/P/N/M) have higher levels of blood organic mercury than other racial/ethnic groups; however, the reasons for this have been unclear. This research uses exposure modeling to determine the reasons for elevated blood methylmercury (MeHg) levels, and also extends previous analyses of observed NHANES blood levels. The probabilistic SHEDS-Dietary model was applied, using MeHg fish residue data from FDA's Total Diet Study (1990-2002) combined with NHANES/WWEIA (1999-2006) fish consumption data, to generate exposure estimates by race/ethnicity, age group, and fish type. Statistical analyses of blood methylmercury levels in the (6 times larger) 1999-2006 NHANES data were compared against previous published results for 1999-2002 data. The A/P/N/M group has higher fish intake, modeled MeHg exposures, and blood levels than the general population and other racial/ethnic groups. Tuna, other saltwater fish, and other freshwater fish are key food types driving dietary MeHg exposure. The 1-<3 years-old A/P/N/M group has the highest mean dietary MeHg intake per body weight (0.06 μg/kg/day; ~2.3 times higher than the rest of the population). Fish intake and modeled exposure predictions correlate well with NHANES blood biomarker levels. This study, using the SHEDS-Dietary model with national data, reinforces and expands upon previous observations that dietary exposure via fish consumption is an important route for methylmercury intake by the general population, and especially for racial/ethnic groups with higher fish consumption. These probabilistic dietary modeling approaches could be applied for local populations (e.g., tribes) and other chemicals and foods, if data are available.

A risk–benefit analysis approach to seafood intake to determine optimal consumption

Seafood provides n-3 long-chain PUFA (n-3 LC-PUFA), vitamins and minerals, which are essential to maintain good health. Moreover, seafood is a source of contaminants such as methylmercury, arsenic and persistent organic pollutants that may affect health. The aim of the present study was to determine in what quantities seafood consumption would provide nutritional benefits, while minimising the risks linked to food contaminants. Seafood was grouped into clusters using a hierarchical cluster analysis. Those nutrients and contaminants were selected for which it is known that seafood is a major source. The risk–benefit analysis consisted in using an optimisation model with constraints to calculate optimum seafood cluster consumption levels. The goal was to optimise nutrient intakes as well as to limit contaminant exposure with the condition being to attain recommended nutritional intakes without exceeding tolerable upper intakes for contaminants and nutrients, while taking into account background intakes. An optimum consumption level was calculated for adults that minimises inorganic arsenic exposure and increases vitamin D intake in the general population. This consumption level guarantees that the consumer reaches the recommended intake for n-3 LC-PUFA, Se and I, while remaining below the tolerable upper intakes for methylmercury, Cd, dioxins, polychlorobiphenyls, Zn, Ca and Cu. This consumption level, which is approximately 200 g/week of certain fatty fish species and approximately 50 g/week of lean fish, molluscs and crustaceans, has to be considered in order to determine food consumption recommendations in a public health perspective.

Comparison of a toxicokinetic and a questionnaire-based approach to assess methylmercury intake in exposed individuals

Methylmercury (MeHg) is a neurotoxic contaminant and one of the main sources of exposure in humans is seafood consumption. It is thus of interest to assess precisely MeHg exposure. The objective of this study was to estimate MeHg daily intake in exposed individuals using two different approaches, a food questionnaire and toxicokinetic modeling, and compare the complementary and use of each method. For this purpose, a group of 23 fishermen from northern Quebec provided blood and hair samples and answered a standard food questionnaire focusing on seafood consumption. A published and validated toxicokinetic model was then used to reconstruct MeHg daily intakes from mercury (Hg) measurements in biological samples. These intakes were compared to those estimated using a standard food questionnaire on seafood consumption. Daily intakes of MeHg from seafood (mean/median (range)) estimated from hair concentrations with the toxicokinetic-based approach were 6.1/5.2 (0.0-19) μg/day. These intake values were on average six times lower than those estimated using a food questionnaire, that is, 49/32 (7.2-163) μg/day. No correlation was found between the toxicokinetic-based and the questionnaire estimates of MeHg daily intakes. Most of the MeHg intakes estimated with the food questionnaire (21/23) exceeded the US EPA RfD of 0.1 μg/kg bw/day, whereas only a small proportion (6/23) of modeled estimates exceeded the RfD. This study shows that human health risk estimates strongly depend on the chosen approach.

Prenatal mercury exposure in a multicenter cohort study in Spain

BACKGROUND

Mercury is a ubiquitous heavy metal that may negatively affect human health. It is desirable to investigate mercury exposure in vulnerable populations.

OBJECTIVE

To determine the concentrations of total mercury (T-Hg) in cord blood and to evaluate the role of maternal fish consumption in a Spanish mother and child cohort.

METHODS

A total of 1883 mother and child pairs from a population-based cohort were included between 2004 and 2008. T-Hg concentrations were measured in whole cord blood and maternal seafood consumption was ascertained by means of a food-frequency questionnaire. Linear regression was used in stratified analyses, while a joint model was adjusted using a mixed-effects linear model.

RESULTS

Maternal daily seafood consumption was 78g/d and the geometric mean for T-Hg was 8.2μg/L. Maternal fish intake during pregnancy, mother's age, country of origin, educational level, employment status and parity, as well as area of study and season of delivery, were associated with cord blood T-Hg levels. A doubling in consumption of large oily fish was associated with an increase of 11.4% (95%CI: 3.8 to 19.6%) in cord blood T-Hg levels, followed by an increase of 8.4% (95%CI: 5.7 to 11.2%) in the case of canned tuna and 8.3% (95%CI: 5.5 to 11.1%) in that of lean fish.

CONCLUSION

A high proportion of newborns had elevated concentrations of cord blood T-Hg according to the current US-EPA reference dose (5.8μg/L for methylmercury). Mercury concentrations were related to maternal fish consumption, with large oily fish being the main contributor.

Determination of 20 trace elements in fish and other seafood from the French market

The levels of 20 essential or toxic trace elements in 159 fish, other seafood and seafood products on the French coastal market collected between January and April 2005 were measured by ICP-MS. The concentration ranges (mg/kg of fresh mass) for the elements determined were compared with previous studies. The contents of Co, Cu, Fe, Li, Mn, Se, Zn and Pb found in fish are close to or often lower than previous studies. For other seafood, comparison is difficult due to the lack of data on a more global scale. However, it should be noted that the contents of Ag were found considerably higher in this study.

Shellfish and residual chemical contaminants: hazards, monitoring, and health risk assessment along French coasts

In this review, we address the identification of residual chemical hazards in shellfish collected from the marine environment or in marketed shellfish. Data, assembled on the concentration of contaminants detected, were compared with the appropriate regulatory and food safety standards. Moreover, data on human exposure and body burden levels were evaluated in the context of potential health risks.Shellfish farming is a common industry along European coasts. The primary types of shellfish consumed in France are oysters, mussels, king scallops, winkles,whelks, cockles, clams, and other scallops. Shellfish filter large volumes of water to extract their food and are excellent bioaccumulators. Metals and other pollutants that exist in the marine environment partition into particular organs, according to their individual chemical characteristics. In shellfish, accumulation often occurs in the digestive gland, which plays a role in assimilation, excretion, and detoxification of contaminants. The concentrations of chemical contaminants in bivalve mollusks are known to fluctuate with the seasons.European regulations limit the amount and type of contaminants that can appear in foodstuffs. Current European standards regulate the levels of micro-biological agents, phycotoxins, and some chemical contaminants in food. Since 2006, these regulations have been compiled into the "Hygiene Package." Bivalve mollusks must comply with maximum levels of certain contaminants as follows:lead (1.5 mg kg-1), cadmium (1 mg kg-1), mercury (0.5 mg kg-1), dioxins (4 pg g-1 and dioxins + DL-PCBs 8 pg g-1), and benzo[a]pyrene (10 μp.g kg-1).In this review, we identify the levels of major contaminants that exist in shellfish(collected from the marine environment and/or in marketed shellfish). The follow-ing contaminants are among those that are profiled: Cd, Pb, Hg, As, Ni, Cr, V,Mn, Cu, Zn, Co, Se, Mg, Mo, radionuclides, benzo[a]pyrene, PCBs, dioxins and furans, PAHs, TBT, HCB, dieldrin, DDT, lindane, triazines, PBDE, and chlorinated paraffins.In France, the results of contaminant monitoring have indicated that Cd, but not lead (< 0.26 mg kg-1) or mercury (< 0.003 mg kg-1), has had some non-compliances. Detections for PCBs and dioxins in shellfish were far below the regulatory thresholds in oysters (< 0.6 pg g-l), mussels (< 0.6 pg g-1), and king scallops (< 0.4 pg g-1). The benzo[a]pyrene concentration in marketed mussels and farmed shellfish does not exceed the regulatory threshold. Some monitoring data are available on shellfish flesh contamination for unregulated organic contaminants.Of about 100 existing organo stannic compounds, residues of the mono-, di-, and tributyltin (MBT, DBT, and TBT) and mono-, di-, and triphenyltin (MPT, DPT,and TPT) compounds are the most frequently detected in fishery products. Octyltins are not found in fishery products. Some bivalve mollusks show arsenic levels up to 15.8 mg kg-1. It seems that the levels of arsenic in the environment derive less from bioaccumulation, than from whether the arsenic is in an organic or an inorganic form. In regard to the other metals, levels of zinc and magnesium are higher in oysters than in mussels.To protect shellfish from chemical contamination, programs have been established to monitor water masses along coastal areas. The French monitoring network(ROCCH) focuses on environmental matrices that accumulate contaminants. These include both biota and sediment. Example contaminants were studied in a French coastal lagoon (Arcachon Bay) and in an estuary (Bay of Seine), and these were used to illustrate the usefulness of the monitoring programs. Twenty-one pesticidal and biocidal active substances were detected in the waters of Arcachon Bay during the summers from 1999 to 2003, at concentrations ranging from a few nanograms per liter to several hundred nanograms per liter. Most of the detected substances were herbicides, including some that are now banned. Organotin compounds have been detected in similarly semi-enclosed waters elsewhere (bays, estuaries, and harbors).However, the mean concentrations of cadmium, mercury, lead, and benzo[a]pyrene,in transplanted mussels, were below the regulatory limits.In 2007, the mean daily consumption of shellfish in the general French population was estimated to be 4.5 g in adults; however, a wide variation occurs by region and season (INCA 2 study). Tabulated as a proportion of the diet, shellfish consumption represents only 0.16% of overall solid food intake. However, the INCA 2 survey was not well suited to estimating shellfish consumption because of the small number of shellfish consumers sampled. In contrast, the mean consumption rate of bivalve mollusks among adult high consumers of fish and seafood products, i.e., adults who eat fish or seafood at least twice a week, was estimated to be 153 g week-1 (8 kg yr-1). The highest mean consumption is for king scallops (39 g week-1), followed by oysters (34 g week-1) and mussels (22 g week-1). Thus, for high seafood consumers, the contribution of shellfish to inorganic contaminant levels is 1-10% TWI or PTWI for Cd, MeHg, and Sn (up to 19% for Sn), and the arsenic body burden is higher for 22% of individuals studied.The human health risks associated with consuming chemical contaminants in shellfish are difficult to assess for several reasons: effects may only surface after long-term exposure (chronic risk), exposures may be discontinuous, and contamination may derive from multiple sources (food, air, occupational exposure, etc.).Therefore, it is not possible to attribute a high body burden specifically to shellfish consumption even if seafood is a major dietary contributor of any contaminant, e.g.,arsenic and mercury.The data assembled in this review provide the arguments for maintaining the chemical contaminant monitoring programs for shellfish. Moreover, the results presented herein suggest that monitoring programs should be extended to other chemicals that are suspected of presenting a risk to consumers, as illustrated by the high concentration reported for arsenic (in urine) of high consumers of seafood products from the CALIPSO study. In addition, the research conducted in shellfish-farming areas of Arcachon Bay highlights the need to monitor TBT and PAH contamination levels to ensure that these chemical pollutants do not migrate from the harbor to oyster farms.Finally, we have concluded that shellfish contamination from seawater offers a rather low risk to the general French population, because shellfish do not constitute a major contributor to dietary exposure of chemical contaminants. Notwithstanding,consumer vigilance is necessary among regular shellfish consumers, and especially for those residing in fishing communities, for pregnant and breast-feeding women,and for very young children.

Food and nutrient intakes of French frequent seafood consumers with regard to fish consumption recommendations: results from the CALIPSO study

Besides providing n-3 fatty acids with nutritional and health benefits, seafood consumption may contribute to the reduction of nutrient prevalences of inadequacy. To evaluate the contributions of seafood and other food groups to nutrient intakes of frequent seafood consumers, food consumption was evaluated through an FFQ on 991 French men and women (18–81 years) consuming seafood at least twice a week. Intakes, prevalence of inadequacies, risks of upper limit excess and food contributions to intakes were assessed for thirty-three nutrients. Mean fat contributions to total energy intakes (38·3 and 39·0 % for men and women, respectively) met French recommendations, but mean carbohydrate intakes (40·9 and 39·7 %, respectively) were insufficient. Micronutrient inadequacies were lower than in the French general population, the highest being for vitamin C (41·3 and 40·1 % for men and women, respectively), vitamin E (35·0 and 35·3 % for men and women, respectively) and Mg (37·5 and 25·5 % for men and women, respectively). Upper safety limits (USL) were exceeded mostly for Zn (6·2 %), Ca (3·7 %), retinol (2·0 %) and Cu (0·9 %). Mean contributions of seafood to vitamin D, B12, I and Se intakes ranged 40–65 %. Molluscs and crustaceans significantly contributed to vitamin B12 (13·7 %), Cu (11·4 %), Fe (11·5 %), Zn (8·4 %) and I (6·1 %) intakes, and canned fish contributed to vitamin D intake (13·4 %). Besides fish, contributions of mollusc and crustacean consumption to nutrient intakes should be considered from a public health viewpoint. Consuming seafood at least twice a week induces moderate inadequacies and risks of exceeding USL for some micronutrients, whereas macronutrient intakes remained imbalanced.

Blood concentration of methylmercury in relation to food consumption

OBJECTIVE

Dietary fish is the main source of methylmercury (MeHg) for man, and fish consumption has been used as a measure of MeHg exposure. However, other dietary sources of exposure exist and MeHg metabolism may also be modified by nutritional factors. The aim of the present study was to examine the association between blood MeHg concentration and consumption of different foods in a Finnish population with high fish consumption.

DESIGN

Blood samples, a detailed FFQ and additional frequency data on fish consumption were collected. MeHg was analysed from whole blood by the isotope dilution method with high-resolution MS. The consumption of different foods was calculated by MeHg quartiles and tested for linear trend.

SETTING

Finnish southern and south-western coast of the Baltic Sea.

SUBJECTS

Two hundred and ninety-nine professional fishermen, their spouses and other family members.

RESULTS

Mean (range) blood MeHg concentration was 4·6 (0·21-22) μg/l among men and 2·8 (<0·15-20) μg/l among women. Fish had the strongest positive association with MeHg (P for linear trend <0·001 among both men and women). Among men, positive associations were also observed for fruit vegetables, wheat and wine. Among women, positive associations were observed for root vegetables, legumes, potato and game, but adjustment for fish consumption attenuated these trends.

CONCLUSIONS

The study shows that, besides fish, MeHg may have other dietary sources that should be taken into account in risk assessment studies. Due to the observed high blood MeHg concentration, a thorough exposure assessment among the general Finnish population is recommended.

Estimation of risk assessment of some heavy metals intake through black scabbardfish (Aphanopus carbo) consumption in Portugal

The intake of Cd, methyl-Hg, and Pb through consumption of black scabbardfish (BSF) (Aphanopus carbo) in Portugal as well as the associated probability of exceeding the respective provisional tolerable weekly intakes (PTWIs) was estimated. For this purpose, the contamination levels of heavy metals in this fish species were combined with constructed consumption scenarios or with a hypothesized consumption distribution. Whereas Cd and Pb posed no serious risk, the consumption of at least one portion of BSF per month as well as the hypothetical study in the Portuguese population produced nonnegligible probabilities of surpassing the PTWI for Me-Hg. Risk assessment for Portuguese consumers revealed a higher risk regarding Me-Hg, 1.19% and 1.81% with the plug-in (PI) and the tail estimation (TE) estimators, respectively. On the other hand, the risk for Cd and Pb was less than 1 in 100,000. TE was more realistic and accurate for Cd and Pb. Concerning Me-Hg, TE and PI estimators produced similar results. Furthermore, the limitations of a deterministic approach were shown.

Methylmercury risks and EPA + DHA benefits associated with seafood consumption in Europe

The intake of methyl-Hg and EPA + DHA through consumption of seafood in Europe as well as the associated probability of exceeding the provisional tolerable weekly intake (PTWI) and the recommended daily intake (RDI), respectively, were estimated by combining methyl-Hg and EPA + DHA contents in the five most consumed seafood species with hypothesized consumption distributions for eight European countries, chosen on the basis of size and representative significance. Two estimators were used: plug-in (PI) and tail estimation (TE). The latter was based on the application of the extreme value theory to the intakes distribution curves. Whereas contents data were collected from own database and published scientific papers, consumption data were obtained from statistical sources of the various countries. Seafood consumption levels varied considerably between countries, from 140 in the United Kingdom to 628.5 g/(person.week) in Iceland. The main consumed species were also different between countries. The probability of exceeding the methyl-Hg PTWI ranged from 0.04% in the United Kingdom to 9.61% in Iceland. Concerning the probability of exceeding the RDI of EPA + DHA, Iceland was third, after Portugal (66.05%) and Spain (61.05%) and the United Kingdom was the last (0.32%). While TE was most accurate for small probabilities, PI yielded best estimates for larger probabilities.

Pesticide exposure of pregnant women in Guadeloupe: ability of a food frequency questionnaire to estimate blood concentration of chlordecone

CONTEXT

Chlordecone, an environmentally persistent organochlorine insecticide used intensively in banana culture in the French West Indies until 1993, has permanently polluted soils and contaminated foodstuffs. Consumption of contaminated food is the main source of exposure nowadays. We sought to identify main contributors to blood chlordecone concentration (BCC) and to validate an exposure indicator based on food intakes.

MATERIAL AND METHODS

We used a food frequency questionnaire (FFQ) completed by a sample of 194 pregnant women to estimate their dietary exposure to chlordecone and compared it to blood levels. In a first approach, chlordecone daily intake was estimated as the product of daily eaten quantity of 214 foodstuffs, multiplied by their chlordecone content, and summed over all items. We then predicted individual blood chlordecone concentration with empirical weight regression models based on frequency of food consumption, and without contamination data.

RESULTS

Among the 191 subjects who had BCC determination, 146 (76%) had detectable values and mean BCC was 0.86 ng/mL (range < LOD-13.2). Mean per capita dietary intake of chlordecone was estimated at 3.3 microg/day (range: 0.1-22.2). Blood chlordecone levels were significantly correlated with food exposure predicted from the empirical weight models (r=0.47, p<0.0001) and, to a lesser extent, with chlordecone intake estimated from food consumption and food contamination data (r=0.20, p=0.007). Main contributors to chlordecone exposure included seafood, root vegetables, and Cucurbitaceous.

CONCLUSION

These results show that the Timoun FFQ provides valid estimates of chlordecone exposure. Estimates from empirical weight models correlated better with blood levels of chlordecone than did estimates from the dietary intake assessment.

Estimated intake levels of methylmercury in children, childbearing age and pregnant women in a Mediterranean region, Murcia, Spain

Methylmercury (MeHg) is a bioaccumulable toxin in the trophic chain and a powerful neurotoxin during fetal and child development. Consumption of contaminated fish and shellfish is a principal environmental source of MeHg exposure. This study was designed to assess the Hg and estimated MeHg intake in vulnerable groups of the Murcia region, a Mediterranean part of Spain, compared with international regulations. A validated food frequency questionnaire was used to assess seafood consumptions in 320 children younger than 10 years, 301 women of childbearing age, and 537 pregnant women. Hg concentrations were measured in the most consumed fish products by cold vapor generation-atomic fluorescence spectrometry. The weekly intake of MeHg (microg/kg bw/week) was 2.60 (95% CI = 2.10-3.10) in children 1-5 years, 2.65 (95% CI = 2.26-3.03) in children 6-10 years, 0.98 (95% CI = 0.89-1.07) in women of childbearing age, and 0.88 (95% CI = 0.81-0.95) in pregnant women. The main exposure to MeHg, especially in young children, is related to intake of bluefin tuna and swordfish. Fifty-four percent of children aged 1-10 years, 10% of pregnant women, and 15% of women of childbearing age exceed the Joint Expert Committee on Food Additives provisional tolerable weekly intake of MeHg. In the Murcia region, where fish is a central component of the diet, the focus should be on educating vulnerable populations to reorient fish consumption in order to lower the amount of Hg incorporated with the diet as well as to reduce Hg emissions into the environment.

Dietary exposure and biomarkers of arsenic in consumers of fish and shellfish from France

Seafood, especially fish, is considered as a major dietary source of arsenic (As). Seafood consumption is recommended for nutritional properties but contaminant exposure should be considered. The objectives were to assess As intake of frequent French seafood consumers and exposure via biomarkers. Consumptions of 996 high consumers (18 and over) of 4 coastal areas were assessed using a validated food frequency questionnaire. Seafood samples were collected according to a total diet study (TDS) sampling method and analyzed for total As, arsenite (AsIII), arsenate (AsV), arsenobetaïne (AsB), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The average As dietary exposure is 94.7+/-67.5 microg/kg bw/week in females and 77.3+/-54.6 microg/kg bw/week in males (p<0.001) and the inorganic As dietary exposure is respectively 3.34+/-2.06 microg/kg bw/week and 3.04+/-1.86 microg/kg bw/week (p<0.05). Urine samples were collected from 382 of the subjects. The average urinary As concentration is 94.8+/-250 microg/g creatinine for females and 59.7+/-81.8 microg/g for males (p<0.001). Samples having an As concentration above 75 microg/g creatinine (n=101) were analyzed for inorganic As (As(III), As(V), MMA(V) and DMA(V)) which was 24.6+/-27.9 microg/g creatinine for males and 27.1+/-20.6 microg/g for females. Analyses do not show any correlation between dietary exposure and urinary As. These results show that biological results should be interpreted cautiously. Diet recording seems to be the best way to assess dietary As exposure. Seafood is a high source of As exposure but even among high consumers it is not the main source of toxic As. From a public health point of view these results should be interpreted carefully in the absence of international consensus on the health-based guidance value.