Impact of consumption of freshwater fish on mercury levels in hair, blood, urine, and alveolar air

Selecting the best non-invasive matrix to measure mercury exposure in human biomonitoring surveys

Exposure to mercury, even at low doses, can affect human health, well-being and life quality at a broad scale. Human biomonitoring is the most straightforward approach to measure and quantify mercury exposure in humans. The objective of the present study is to compare and discuss the relationships between Hg levels in the most used matrices, hair, urine and blood, with the aim to ascertain to what extent mercury exposure and internal mercury levels could be predicted by monitoring non-invasive matrices. The study population (n = 527) is a subsample from Spanish BIOAMBIENT. ES study (18-65 y, both sexes), with data of Hg levels in blood, hair, and urine from the same individuals. We found strong inter-matrix Spearman correlations between blood and hair mercury (r² = 0.84), while the correlations for urine and blood mercury (r²⁼0.64) and urine and hair mercury (r²⁼0.65) were weaker. The geometric mean of the ratios between matrices were (GM, 95%CI): Hair/Blood 280 (271-290), Urine/Blood 0.174 (0.163-0.186) and Hair/Urine 2070 (1953-2194) and Urine/Blood 0.135 (0.128-0.144) for urine corrected by creatinine. High individual variation was observed particularly in those ratios involving urine. Considering the wide range of values observed in the ratios, we do not recommend applying them at individual level. The predictive models indicate that hair Hg was a more accurate predictor than urine. The inclusion of urine values did not increase the predictive accuracy, so, we recommend a cautious interpretation of urine mercury levels. Our study presents clear evidence that in a population highly exposed to food-borne mercury, a large portion of urinary mercury primarily emanates from methylmercury demethylation. We conclude that urine, as a non-invasive matrix, can be used as a reliable qualitative biomarker for Hg exposure when hair measurements not are available. For quantitative individual assessments, still blood measurements are to be preferred.

Hair to blood mercury concentration ratios and a retrospective hair segmental mercury analysis in the Northwest Territories, Canada

Concentrations of total mercury were measured in blood and hair samples collected as part of a human biomonitoring project conducted in First Nations communities of the Mackenzie Valley, Northwest Territories, Canada. Hair (n = 443) and blood (n = 276) samples were obtained from six communities in the Dehcho region and three communities in the Sahtú region of the Mackenzie Valley. The aim of this paper was to calculate hair to blood mercury ratios (for matched samples) and determine if: 1) ratios differed significantly between the two regions; 2) ratios differed from the 250:1 ratio proposed by the WHO; and, 3) point estimates of hair to blood mercury ratios could be used to estimate blood mercury concentrations. In addition, this paper aims to determine if there were seasonal patterns in hair mercury concentrations in these regions and if so, if patterns were related to among-season variability in fish consumption. The majority of mercury levels in hair and blood were below relevant health-based guidance values. The geometric mean hair (most recent segment) to blood mercury ratio (stratified by region) was 619:1 for the Dehcho region and 1220:1 for the Sahtú region. Mean log-transformed hair to blood mercury ratios were statistically significantly different between the two regions. Hair to blood ratios calculated in this study were far higher (2-5 times higher) than those typically reported in the literature and there was a large amount of inter-individual variation in calculated ratios (range: 114:1 to 4290:1). Using the 250:1 ratio derived by the World Health Organisation to estimate blood mercury concentrations from hair mercury concentrations would substantially over-estimate blood mercury concentrations in the studied regions. However, geometric mean site-specific hair to blood mercury ratios can provide estimates of measures of central tendency for blood mercury concentrations from hair mercury concentrations at a population level. Mercury concentrations were determined in segments of long hair samples to examine exposure of participants to mercury over the past year. Hair segments were assigned to six time periods and the highest hair mercury concentrations were generally observed in hair segments that aligned with September/October and November/December, whereas the lowest hair mercury concentrations were aligned with March/April and May/June. Mean log-transformed hair mercury concentrations were statistically significantly different between time periods. Between time periods (e.g., September/October vs. March/April), the geometric mean mercury concentration in hair differed by up to 0.22 μg/g, and the upper margins of mercury exposure (e.g., 95th percentile of hair mercury) varied by up to 0.86 μg/g. Results from self-reported fish consumption frequency questionnaires (subset of participants; n = 170) showed total fish intake peaked in late summer, decreased during the winter, and then increased during the spring. Visual assessment of results indicated that mean hair mercury concentrations followed this same seasonal pattern. Results from mixed effects models, however, indicated that variability in hair mercury concentrations among time periods was not best explained by total fish consumption frequency. Instead, seasonal trends in hair mercury concentrations may be more related to the consumption of specific fish species (rather than total wild-harvested fish in general). Future work should examine whether seasonal changes in the consumption of specific fish species are associated with seasonal changes in hair mercury concentrations.

A population approach for the estimation of methylmercury ToxicoKinetics in red mullets

It is known that, as the vast majority of the anthropogenically emitted mercury can be found in aquatic ecosystems, where several methylating bacteria are present, fish consumption represents the most critical intake source of the most toxic form of mercury, the methylmercury (MeHg). The aim of this work is to predict MeHg levels in the fish muscles which, being the edible portion, are part of the human diet. A physiologically based toxicokinetics model was developed to evaluate the kinetics of MeHg in red mullets. Fishes were described by means of a multi-compartment model including stomach, gut, blood, muscles and an additional compartment virtually encompassing all the remaining organs. Absorption, distribution and excretion were modelled considering different MeHg routes of administration and excretion: intake by ingestion of contaminated food, intake and elimination through inhalation-exhalation and excretion through feces. The model has been firstly validated on Terapon jarbua fish (using the weighted least squares method for parameter estimation) to be subsequently readapted to predict methylmercury concentrations in the muscle of red mullets (using an approximate Bayesian computation approach). This simple multicompartmental model could be considered part, a link in the chain, of a wider more complex project aiming at tracking the fate of MeHg from polluted seawater to the human end consumer. The present study could be useful to surveillance organizations in order to carry out a more comprehensive and informed risk assessment analysis and to take appropriate preventive measures by evaluating possible new MeHg concentration thresholds to minimize public health hazards.

Methanogenesis Is an Important Process in Controlling MeHg Concentration in Rice Paddy Soils Affected by Mining Activities

Rice paddies are agricultural sites of special concern because the potent toxin methylmercury (MeHg), produced in rice paddy soils, accumulates in rice grains. MeHg cycling is mostly controlled by microbes but their importance in MeHg production and degradation in paddy soils and across a Hg concentration gradient remains unclear. Here we used surface and rhizosphere soil samples in a series of incubation experiments in combination with stable isotope tracers to investigate the relative importance of different microbial groups on MeHg production and degradation across a Hg contamination gradient. We showed that sulfate reduction was the main driver of MeHg formation and concentration at control sites, and that methanogenesis had an important and complex role in MeHg cycling as Hg concentrations increased. The inhibition of methanogenesis at the mining sites led to an increase in MeHg production up to 16.6-fold and a decrease in MeHg degradation by up to 77%, suggesting that methanogenesis is associated with MeHg degradation as Hg concentrations increased. This study broadens our understanding of the roles of microbes in MeHg cycling and highlights methanogenesis as a key control of MeHg concentrations in rice paddies, offering the potential for mitigation of Hg contamination and for the safe production of rice in Hg-contaminated areas.

A Review on the Status of Mercury Pollution in Pakistan: Sources and Impacts

Mercury (Hg) contamination in environmental matrices and associated human exposure has been recognized as a critical long-lasting issue worldwide. However, studies are still elusive that summarized the overall status of Hg pollution and its impacts on public health in Pakistan. Hence, this review encompasses the environmental prevalence, potential sources, and human exposure tendencies to Hg contamination in Pakistan. Reviewed literature revealed jolting levels of Hg in various environmental samples, such as dust, soil, water, and air collected from the residential and industrial areas. Inhalation of Hg via dust particle was identified as the primary pathway for human exposure, while atmospheric deposition and gold mining are identified as the two primary sources of Hg contamination in the environment. Considering human exposure, the highest bioaccumulation of Hg was ranged from 5885 to 8698 µg/kg in hair samples collected from the residents of the Kashmir Valley, Pakistan. However, in the lower Himalayan regions, including Islamabad and Swabi, the concentration of Hg in hair samples was reported at 1085 µg/kg, slightly beyond WHO devised reference dose (RfD) of Hg (1000 µg/kg). This review revealed the worst scenario of Hg contamination in human biomatrices and environmental compartments in Pakistan, which needed immediate rehabilitation measures.

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.

Mercury Exposure in Children of the Wanshan Mercury Mining Area, Guizhou, China

To evaluate the mercury (Hg) exposure level of children located in a Hg mining area, total Hg concentrations and speciation were determined in hair and urine samples of children in the Wanshan Hg mining area, Guizhou Province, China. Rice samples consumed by these same children were also collected for total mercury (THg) and methyl-mercury (MeHg) analysis. The geometric mean concentrations of THg and MeHg in the hair samples were 1.4 (range 0.50-6.0) μg/g and 1.1 (range 0.35-4.2) μg/g, respectively, while the geometric mean concentration of urine Hg (UHg) was 1.4 (range 0.09-26) μg/g Creatinine (Cr). The average of the probable daily intake (PDI) of MeHg via rice consumption was 0.052 (0.0033-0.39) µg/kg/day, which significantly correlated with the hair MeHg concentrations (r = 0.55, p < 0.01), indicating that ingestion of rice is the main pathway of MeHg exposure for children in this area. Furthermore, 18% (26/141) of the PDIs of MeHg exceeded the USEPA Reference Dose (RfD) of 0.10 µg/kg/day, indicating that children in this area are at a high MeHg exposure level. This paper for the first time evaluates the co-exposure levels of IHg and MeHg of children living in Wanshan mining area, and revealed the difference in exposure patterns between children and adults in this area.

The complexity of hair/blood mercury concentration ratios and its implications

BACKGROUND

The World Health Organization (WHO) recommends a mercury (Hg) hair-to-blood ratio of 250 for the conversion of Hg hair levels to those in whole blood. This encouraged the selection of hair as the preferred analyte because it minimizes collection, storage, and transportation issues. In spite of these advantages, there is concern about inherent uncertainties in the use of this ratio.

OBJECTIVES

To evaluate the appropriateness of the WHO ratio, we investigated total hair and total blood Hg concentrations in 1333 individuals from 9 First Nations (Aboriginal) communities in northern Québec, Canada.

METHODS

We grouped participants by sex, age, and community and performed a 3-factor (M)ANOVA for total Hg in hair (0-2 cm), total Hg in blood, and their ratio. In addition, we calculated the percent error associated with the use of the WHO ratio in predicting blood Hg concentrations from hair Hg. For group comparisons, Estimated Marginal Means (EMMS) were calculated following ANOVA.

RESULTS

At the community level, the error in blood Hg estimated from hair Hg ranged -25% to +24%. Systematic underestimation (-8.4%) occurred for females and overestimation for males (+5.8%). At the individual level, the corresponding error range was -98.7% to 1040%, with observed hair-to-blood ratios spanning 3 to 2845.

CONCLUSIONS

The application of the ratio endorsed by the WHO would be unreliable for determining individual follow-up. We propose that Hg exposure be assessed by blood measurements when there are human health concerns, and that the singular use of hair and the hair-to-blood concentration conversion be discouraged in establishing individual risk.

Hair mercury and urinary cadmium levels in Belgian children and their mothers within the framework of the COPHES/DEMOCOPHES projects

A harmonized human biomonitoring pilot study was set up within the frame of the European projects DEMOCOPHES and COPHES. In 17 European countries, biomarkers of some environmental pollutants, including urinary cadmium and hair mercury, were measured in children and their mothers in order to obtain European-wide comparison values on these chemicals. The Belgian participant population consisted in 129 school children (6-11 years) and their mothers (≤ 45 years) living in urban or rural areas of Belgium. The geometric mean levels for mercury in hair were 0.383 μg/g and 0.204 μg/g for respectively mothers and children. Cadmium in mother's and children's urine was detected at a geometric mean concentration of respectively 0.21 and 0.04 μg/l. For both biomarkers, levels measured in the mothers and their child were correlated. While the urinary cadmium levels increased with age, no trend was found for hair mercury content, except the fact that mothers hold higher levels than children. The hair mercury content increased significantly with the number of dental amalgam fillings, explaining partially the higher levels in the mothers by their higher presence rate of these amalgams compared to children. Fish or seafood consumption was the other main parameter determining the mercury levels in hair. No relationship was found between smoking status and cadmium or mercury levels, but the studied population included very few smokers. Urinary cadmium levels were higher in both mothers and children living in urban areas, while for mercury this difference was only significant for children. Our small population showed urinary cadmium and hair mercury levels lower than the health based guidelines suggested by the WHO or the JECFA (Joint FAO/WHO Expert Committee on Food Additives). Only 1% had cadmium level slightly higher than the German HBM-I value (1 μg/l for adults), and 9% exceeded the 1 μg mercury/g hair suggested by the US EPA.

Methylmercury-induced inhibition of paraoxonase-1 (PON1)-implications for cardiovascular risk

Methylmercury (MeHg) has been associated with increased risk for cardiovascular disease in some but not all epidemiology studies. These inconsistent results may stem from the fact that exposure typically occurs in the context of fish consumption, which is also associated with cardioprotective factors such as omega-3 fatty acids. Mechanistic information may help to understand whether MeHg represents a risk to cardiovascular health. MeHg is a pro-oxidant that inactivates protein sulfhydryls. These biochemical effects may diminish critical antioxidant defense mechanism(s) involved in protecting against atherosclerosis. One such defense mechanism is paraoxonase-1 (PON1), an enzyme present on high-density lipoproteins and that prevents the oxidation of blood lipids and their deposition in vascular endothelium. PON1 is potentially useful as a clinical biomarker of cardiovascular risk, as well as a critical enzyme in the detoxification of certain organophosphate oxons. MeHg and other metals are known to inhibit PON1 activity in vitro. MeHg is associated with lowered serum PON1 activity in a fish-eating population. The implications of lowering PON1 are evaluated by predicting the shift in PON1 population distribution induced by various doses of MeHg. An MeHg dose of 0.3 μg/kg/d is estimated to decrease the population average PON1 level by 6.1% and to increase population risk of acute cardiovascular events by 9.7%. This evaluation provides a plausible mechanism for MeHg-induced cardiovascular risk and suggests means to quantify the risk. This case study exemplifies the use of upstream disease biomarkers to evaluate the additive effect of chemical toxicity with background disease processes in assessing human risk.

Association between Low-level Mercury Exposure and Neurobehavioral Functions in Korean Adults Living in a Coastal City

OBJECTIVES

The aim of this study was to determine the association between low-level mercury exposure and neurobehavioral functions in adults living in coastal regions of Korea.

METHODS

We selected 172 adults aged 20-65 years living in a city in the coastal region of Korea. A sociodemographic survey was conducted, mercury levels in the blood, urine, and hair were measured, and the associations according to computerized neurobehavioral tests were determined using univariate analysis. After adjustment for associated variables, a multivariate linear regression analysis was performed.

RESULTS

The geometric mean mercury levels in the blood, urine, and hair were 5.41 µg/L (range, 0.00-15.84 µg/L), 1.17 µg/g-creatinine (range, 0.00-32.86 µg/g-creatinine), and 1.37 mg/kg (range, 0.42-6.56 mg/kg), respectively. Variables that were associated with simple reaction time according to the neurobehavioral test results were age and urine mercury level. Variables associated with choice reaction time were the recent use of Korean traditional medicine and urine mercury level. Variables associated with the right-hand finger tapping speed test were age, gender, smoking behavior, education level, monthly household income, and urine mercury level. Variables associated with the left-hand finger tapping speed test were age, gender, education level, and urine mercury level. After adjustment for associated variables, there was no significant association between urine mercury level and simple reaction time (β=25.96; p=0.47), choice reaction time (β=50.37; p=0.32), or the number of left-hand finger taps (β=-1.54; p=0.21). However, urine mercury level was significantly associated with the number of right-hand finger taps (β=-3.86; p=0.01).

CONCLUSIONS

We found no evidence that low-level mercury exposure in adults is associated with deficits in neurobehavioral functions. A longer follow-up study is required to confirm this conclusion.

Can fish consumption advisories do better? Providing benefit and risk information to increase knowledge

Humans exposed to methylmercury (MeHg) can suffer from adverse health impacts, e.g., serious neurological damage; however, fish is also a good source of omega-3 fish oils which promotes infants' neurological development. Because eating fish is the primary mechanism of MeHg exposure, federal and state agencies issue fish consumption advisories to inform the public about the risks of eating contaminated fish. An advisory's purpose is to provide information to consumers to increase their knowledge of specific product attributes; however, the difficulty in communicating both the risks and benefits of eating fish leads readers of fish advisories to over-restrict their fish consumption. Because the effectiveness of fish consumption advisories are not often evaluated by states, we help fill this gap by evaluating the effectiveness of Maine's fish consumption advisory in terms of improving knowledge. The results suggest the advisory successfully increased women's knowledge of both the benefits and risks of consuming fish while pregnant. The advisory also increased their ability to differentiate fish by their MeHg content, knowledge of both low and high-MeHg fish and knowledge of detailed attributes of seemingly substitutable goods, such as white tuna, light tuna and pre-packaged salmon. People who did not read the advisory lack the knowledge of how to identify fish that provide: health benefits like Omega-3 fatty acids, or health risks like MeHg; reading the advisory reduces this lack of knowledge. Readers increased ability to make specific substitutions to minimize risk while maintaining the benefits of fish eating suggests the advisory has the potential of reducing MeHg-related health risks while avoiding the drop in fish consumption show in other studies.

Mercury contamination of fish and shrimp samples available in markets of Mashhad, Iran

Fish and shrimp are common healthy sources of protein to a large percentage of the world's population. Hence, it is vital to evaluate the content of possible contamination of these marine-foods. Six species of fishes and two species of shrimps were collected from the local markets of Mashhad, Iran. The mercury (Hg) concentration of samples was determined by atomic absorption spectrophotometry using a mercuric hydride system (MHS 10). High concentration of total Hg was found in Clupeonella cultriventris caspia (0.93 ± 0.14 μg/g) while the lowest level was detected in Penaeus indicus (0.37 ± 0.03 μg/g). Mean Hg levels in fish and shrimp samples were 0.77 ± 0.08 μg/g and 0.51 ± 0.05 μg/g, respectively. Farmed species (except for P. indicus) and all samples from Persian Gulf and the Caspian Sea had mean mercury concentrations above 0.5 μg/g, which is the maximum standard level recommended by Joint FAO/WHO/Expert Committee on Food Additives (JECFA). All samples had also mean Hg concentrations that exceeded EPA's established safety level of 0.3 μg/g. A little more extensive analysis of data showed that weekly intake of mercury for the proportion of the Iranian population consuming Hg contaminated fish and shrimp is not predicted to exceed the respective provisional tolerable weekly intakes recommended by JECFA. However, the Iranian health and environmental authorities should monitor Hg contamination of the fishes and shrimps before marketing.

Lead, mercury, and cadmium in blood and their relation to diet among Swedish adults

The aim of the present study was to examine the body burden of lead (Pb), mercury (Hg), and cadmium (Cd) in blood among Swedish adults and the association between blood levels, diet and other lifestyle factors. The study was based on a subgroup (n=273) of the national survey Riksmaten 2010-2011 (4-day food records and questionnaire). Lead, Hg, and Cd were measured in whole blood, and Cd additionally in urine, by mass or fluorescence spectrometry methods. The median values (5-95th percentiles) of the metals in blood were as follows; Pb: 13.4 (5.8-28.6) μg/L, Hg: 1.13 (0.31-3.45) μg/L, and Cd: 0.19 (0.09-1.08) μg/L. All three metals increased with increasing age. Lead levels in blood were positively associated with intakes of game and alcohol, Hg was related to fish intake, and blood Cd related to smoking and low iron stores and to a low meat intake. Body burdens of the studied metals were generally below health based reference values, but several individuals had blood Pb levels above the reference point for possible nephrotoxic and developmental neurotoxic effects. As health effects cannot be excluded, individuals with high Pb exposure should aim at decreasing their body burden, both from food and from other exposure routes.

Mercury exposure assessment in Iranian pregnant women's hair with respect to diet, amalgam filling, and lactation

Our aim for carrying out this study was to estimate the levels of mercury in the hair of pregnant women and its association with fish consumption and amalgam fillings. From November 2007 to January 2008, 100 hair samples were collected randomly from three groups of pregnant women: Ahvaz in the south of Iran, Noushahr in the north, and the countryside of Noushahr. Significant differences were found in these three groups of pregnant women's samples (p>0.05). The mean mercury level in women's hair was found to be 0.37 μg/g (range, 0.11-3.57 μg/g). Only in 2 % of collected hair samples did the total mercury (THg) level exceed the United States Environmental Protection Agency-recommended 1.0 μg/g. In addition, there was a positive correlation of THg content in Ahvaz group's samples with respect to fish consumption (r=0.41, p=0.02) and a negative correlation of THg content in those who consumed vegetables and fruit. The level of education also played an indicating factor in this group. Moreover, significant association was found between the residence time and Hg concentration of women's hair samples collected from Noushahr (p>0.05). Similarly, the same correlations were found between hair mercury levels and the time since the first filling, number of dental fillings, pregnancy interval, and lactating period.

Evaluation of glutathione S-transferase GSTM1 and GSTT1 polymorphisms and methylmercury metabolism in an exposed Amazon population

Over the last decades, the presence of methylmercury (MeHg) in the Amazon region of Brazil and its adverse human health effects have given rise to much concern. The biotransformation of MeHg occurs mainly through glutathione (GSH) in the bile mediated by conjugation with glutathione S-transferases (GST). Epidemiological evidence has shown that genetic polymorphisms may affect the metabolism of MeHg. The aim of this study was to evaluate the association between GST polymorphisms, GSH, and Hg levels in blood (B-Hg) and in hair (H-Hg) of an Amazon population chronically exposed to the metal through fish consumption. Blood and hair samples were collected from 144 volunteers (71 men, 73 women). B-Hg and H-Hg levels were determined by inductively coupled plasma-mass spectrometry, and GSH levels were evaluated by a spectrophotometric method. GSTM1 and T1 genotyping evaluation were carried out by multiplex polymerase chain reaction (PCR). Mean levels of B-Hg and H-Hg were 37.7 ± 24.5 μg/L and 10.4 ± 7.4 μg/g, respectively; GSH concentrations ranged from 0.52 to 2.89 μM/ml of total blood. Distributions for GSTM1/T1, GSTM1/GSTT1*0, GSTM1*0/T1, and GSTM1*0/GSTT1*0 genotypes were 35.4, 22.2, 25.0, and 17.4%, respectively. GSTT1 genotype carriers presented lower levels of B-Hg and H-Hg when compared to other genotypes carriers. In addition, GSTM1*0/GSTT1*0 individuals presented higher Hg levels in blood and hair than subjects presenting any other genotypes. There appeared to be no evidence of an effect of polymorphisms on GSH levels. Therefore, our data suggest that GST polymorphisms may be associated with MeHg detoxification.

Development and evaluation of a dynamic model that projects population biomarkers of methylmercury exposure from local fish consumption

A dynamic model was developed to project Hg concentrations in common biomarkers of exposure in response to changes in Hg concentrations in predatory fish from local waters. The model predicts biomarkers in susceptible populations for intake rates representing the mean, 90th, 95th, and 99 th percentiles of populations of interest. The biomarkers the model calculates are blood methylmercury, total hair Hg, and fetal blood methylmercury. Decision makers can use the model to determine the degree of reduction in fish tissue Hg levels necessary to protect the health of susceptible populations. Biomarker output was calibrated with literature sources. Output was then compared to additional literature sources to evaluate model function. Projected biomarkers were not different from literature sources. The model can be used as a tool to understand the impact of local fish consumption on susceptible populations.

Awake at the switch: improving fish consumption advisories for at-risk women

Eating fish provides health benefits; however, nearly all fish contain at least some methylmercury which can impair human health. While government agencies have been issuing fish consumption advisories for 40 years, recent evaluation efforts highlight their poor performance. The benefit of an advisory can be measured by its ability to inform consumers as to both the positive and negative attributes of their potential choices, leading to appropriate changes in behavior. Because of the health benefits, fish advisories should not reduce fish consumption, even among at-risk individuals, but should lead consumers to switch away from highly contaminated fish toward those less contaminated. Although studies document how advisories reduce fish consumption (a negative outcome), no study indicates whether they lead to switching behavior (a positive outcome). We explore the effects of Maine Center of Disease Control and Prevention's advisory aimed at informing women who may become pregnant, nursing mothers and pregnant women about the benefits and risks of fish consumption. We examine how the advisory changes consumption, especially related to switching behavior. We demonstrate such changes in behavior both during and after pregnancy and compare the advisory-induced changes with those induced by other information sources. Although we find the advisory reduced some women's consumption of fish, we find the decrease is short-lived. Most importantly, the advisory induced appropriate switching behavior; women reading the advisory decreased their consumption of high-risk fish and increased their consumption of low-risk fish. We conclude a well-designed advisory can successfully transform a complex risk/benefit message into one that leads to appropriate knowledge and behavioral changes.

Determinants of exposure to mercury in hair from inhabitants of the largest mercury mine in the world

Mercury exposure of the local population was assessed in two areas of the Almadén mercury mining district, Spain, which has been the world's largest producer of this element. Two groups, who are exposed to different sources of mercury, from a point source in Almadén and a diffuse source hundreds of kilometres away in the same region, were studied. Total mercury (THg) in human hair ranged from 0.20 to 9.35 mg kg(-1) and the mean value was 2.64 mg kg(-1). About 87% of subjects had THg levels in excess of the EPA reference dose (RfD=1.0 mg kg(-1)), while a high percentage (68%) of them live in Almadén. There was a clear increase in hair Hg with reported fish consumption and the highest mean hair mercury level was 4 times the RfD in a group who had reported the highest consumption of fish. For the whole group, there was a significant effect of age, gender and fish consumption in relation to Hg concentration in the hair. Nevertheless, when both groups were tested separately by means of a multivariate regression model, there was significant exposure in those living near the mine area. Several factors such as age, gender and fish consumption remained statistically significant and were associated with THg. The main conclusion is that people living close to the hot spot are more impacted by mercury than people living further away. The intake of Hg through consumption of fish is an important parameter for Hg exposure; however, in the case of people living close to the hot spot, their levels are related to the highly Hg-impacted living environment.

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 contamination: relationship with maternal seafood consumption during pregnancy and fetal growth in the 'EDEN mother-child' cohort

Maternal seafood intake is of great health interest since it constitutes an important source of n-3 fatty acids, but provides also an important pathway for fetal exposure to Hg. The objective of the present study was to determine associations between Hg contamination and both maternal seafood consumption and fetal growth in French pregnant women. Pregnant women included in the 'EDEN mother-child' cohort study answered FFQ on their usual diet in the year before and during the last 3 months of pregnancy, from which frequencies of seafood intake were evaluated. Total hair-Hg level was determined for the first 691 included women. Associations between Hg level, seafood intake and several neonatal measurements were studied using linear regressions adjusted for confounding variables. The median Hg level for mothers was 0.52 μg/g. Maternal seafood intake was associated with Hg level (r 0.33; P < 0.0001). There was no association between Hg level and fetal growth in the whole sample of women, except for an early negative relationship with biparietal diameter. A positive association was found between seafood intake and fetal growth in overweight women only which remained unchanged after adjustment for Hg level (birth weight: +101 g for a difference of 1 sd in seafood consumption; P = 0.008). Although seafood intake was associated with Hg contamination in French pregnant women, the contamination level was low. There was no consistent association between Hg level and fetal growth. Taking into account Hg level did not modify associations between seafood intake and fetal growth.

Human mercury exposure and adverse health effects in the Amazon: a review

This paper examines issues of human mercury (Hg) exposure and adverse health effects throughout the Amazon region. An extensive review was conducted using bibliographic indexes as well as secondary sources. There are several sources of Hg (mining, deforestation, reservoirs), and exposure takes place through inhalation or from fish consumption. There is a wide range of exposure, with mean hair-Hg levels above 15 microg/g in several Amazonian communities, placing them among the highest reported levels in the world today. Dietary Hg intake has been estimated in the vicinity of 1-2 microg/kg/day, considerably higher than the USEPA RfD of 0.1 microg/kg/day or the World Health Organization recommendation of 0.23 microg/kg/day. Neurobehavioral deficits and, in some cases, clinical signs have been reported both for adults and children in relation to Hg exposure in several Amazonian countries. There is also some evidence of cytogenetic damage, immune alterations, and cardiovascular toxicity. Since fish provide a highly nutritious food source, there is an urgent need to find realistic and feasible solutions that will reduce exposure and toxic risk, while maintaining healthy traditional dietary habits and preserving this unique biodiversity.

Prenatal and early childhood exposure to mercury and methylmercury in Spain, a high-fish-consumer country

Exposure to mercury, a risk factor for neurodevelopmental toxicity, was assessed in Spanish children (preschool children and newborns, n = 218) in a four-locations survey by performing mercury determination in hair. To assess the prenatal and children's exposure and its potential risk, total mercury (THg) and methylmercury (MeHg) were analyzed and examined for associations with maternal sociodemographic characteristics and dietary intake through interviews and food frequency questionnaires. The mean THg in hair was 0.94 microg/g, ranging from 0.19 to 5.63 microg/g in preschool children and 1.68 microg/g (0.13-8.43 microg/g) in newborns. Associations between mercury levels in hair and fish consumption frequency were found regardless of the group evaluated. Neither other food item nor maternal covariates were associated with mercury levels in the newborn group. In children, the mean THg values among frequent fish consumers (more than four times per week) were almost threefold higher compared with non-consumers (1.40 vs. 0.49 microg/g). Newborns from mothers who had intake of fish two or more times per week exhibited nearly threefold higher hair levels than those who rarely or never consumed fish (2.26 vs. 0.78 microg/g). Finally, mercury levels in hair exceeded the EPA reference dose (RfD) of 0.1 microg Hg/kg body weight per day (equivalent to 1 microg Hg/g hair) in 42% of the population studied. Overall, we conclude that levels of mercury in Spain are among the highest in the non-exposed populations probably because of the relatively high fish consumption.

Urine mercury excretion following meso-dimercaptosuccinic acid challenge in fish eaters

CONTEXT

Public awareness of methylmercury in fish has caused patients to seek testing for mercury poisoning. In some patients, the diagnosis of mercury poisoning has been made based on urine mercury excretions following oral dosing of meso-dimercaptosuccinic acid (DMSA), a metal chelator. However, studies comparing urine mercury excretion following DMSA in healthy non-fish eaters with healthy fish eaters could not be located.

OBJECTIVES

To describe urinary mercury excretion before and after DMSA in healthy fish eaters and non-fish eaters, and to determine whether urine mercury excretion after DMSA would rise above baseline levels to a greater extent in fish eaters.

DESIGN

A total of 24 healthy physicians were assigned to 1 of 3 groups based on fish consumption: non-fish eaters; 1 to 2 fish servings per week; and 3 or more servings per week. Blood mercury concentrations and 12-hour urine mercury and creatinine excretions were measured before and after oral ingestion of 30 mg of DMSA per kilogram of body weight.

RESULTS

A total of 24 subjects completed the study, and 2 subsequently were excluded. No difference in baseline urinary mercury excretion was detected between groups. All groups demonstrated an increase in urinary mercury excretion following DMSA, which was higher in fish eaters (P = .04). Multiple linear regression found that the best predictor of a rise in urine mercury excretion following DMSA challenge was the prechelation blood mercury concentration.

CONCLUSIONS

In this study of healthy physicians, oral DMSA produced a rise in urine mercury excretion both in non-fish eaters and fish eaters. The increase in chelated mercury excretion was higher in fish eaters. A simple rise in chelated mercury excretion over baseline excretion is not a reliable diagnostic indicator of mercury poisoning.

Scalp hair and urine mercury content of children in the Northeast United States: the New England Children's Amalgam Trial

Children may be at particular risk from toxic effects of mercury (Hg). Previous studies of hair (organic) and urine (inorganic) Hg levels in US children were unable to assess Hg levels while accounting for exposure to amalgam dental restorations. This analysis describes, over a 5-year period, levels and correlates/predictors of scalp hair (H-Hg) and urinary (U-Hg) mercury in 534 New England Children's Amalgam Trial (NECAT) participants, aged 6-10 years and without exposure to dental amalgam at baseline.

RESULTS

Mean H-Hg levels were between 0.3 and 0.4 microg/g over 5 years. 17-29% of children had H-Hg levels > or = 0.5 microg/g, and 5.0 to 8.5% of children had levels > or = 1 microg/g, in any given study year. In adjusted models, fish consumption frequency was the most robust predictor of high H-Hg. U-Hg mean levels were between 0.7 and 0.9 microg/g creatinine over two years. The percentage of those with U-Hg > or 2.3 microg/g creatinine ranged from 4% to 6%. Number of amalgam restorations had a significant dose-response relationship with U-Hg level. Daily gum chewing in the presence of amalgam was associated with high U-Hg.

Dental amalgam exposure and urinary mercury levels in children: the New England Children's Amalgam Trial

BACKGROUND

Urinary mercury (U-Hg) excretion is a commonly used biomarker for mercury exposure from dental amalgam restorations.

OBJECTIVES

Our goal was to determine the most efficient measure of dental amalgam exposure for use in analyses concerning U-Hg in children.

METHODS

We analyzed time-sensitive longitudinal amalgam exposure data in children randomized to amalgam restorations (n = 267) during the 5-year New England Children's Amalgam Trial. We calculated 8 measures of amalgam, evaluating current versus cumulative exposure, teeth versus surfaces, and total versus posterior occlusal amalgams. Urine samples collected during follow-up years 3-5 were analyzed for mercury excretion. Multivariate models for current and cumulative U-Hg excretion estimated associations between exposures and U-Hg.

RESULTS

At the end of follow-up, the average (+/- SD) cumulative exposure was 10.3 +/- 6.1 surfaces and 5.7 +/- 2.9 teeth ever filled with amalgam, corresponding to 30 +/- 21 surface-years. Amalgam measures and U-Hg were moderately correlated. Of amalgam exposure measures, the current total of amalgam surfaces was the most robust predictor of current U-Hg, whereas posterior occlusal surface-years was best for cumulative U-Hg. In multivariate models, each additional amalgam surface present was associated with a 9% increase in current U-Hg, and each additional posterior occlusal surface-year was associated with a 3% increase in cumulative U-Hg excretion (p < 0.001).

CONCLUSIONS

One single measure of amalgam exposure is insufficient. Studies of cumulative effects of mercury from amalgam exposure in children are likely to have improved validity and precision if time-sensitive amalgam exposure measures are used. In contrast, simple counts of current amalgam fillings are adequate to capture amalgam-related current U-Hg.

Hair mercury levels in an urban population from southern Italy: fish consumption as a determinant of exposure

Mercury levels in hair of a general population, 237 adults aged between 35-45, in Naples, Italy, were assessed. The subjects were asked to fill in a questionnaire about age, gender, body weight, height, body mass index (BMI), fish consumption, number, surface and area of dental amalgam fillings. Total mercury (THg) concentrations in human hair ranged from 0.221 to 3.402 microg/g and the mean value for the subjects under study was 0.638 microg/g. Study participants were divided into three groups in accordance with fish consumption and dental amalgam: ANF (amalgam and no fish); NAF (no amalgam but with fish) and AAF (amalgam and fish). Significant differences in THg were found in the three groups (p<0.05). A multiple linear regression analysis showed a weak but significant correlation of THg content in hair with respect to gender and age, but almost no association was found between THg and dental fillings. Conversely, a strong correlation was obtained between THg and fish consumption regardless of the group evaluated. Finally, mercury levels in hair exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 microg Hg/kg body weight per day (1 microg Hg/g hair) in 6% of the population (4% men and 2% women). However, the THg limits in our subjects were not exceeded according to the WHO guidelines, which use a benchmark dose of 0.23 microg Hg/kg bw/day (14 microg Hg/g maternal hair).

High-fish consumption and risk prevention: assessment of exposure to methylmercury in Portugal

The aim of this study was to evaluate the exposure to methylmercury (MeHg) of potential populations at risk living in Portugal. To ascertain youth exposure, a questionnaire was distributed to 300 students of a middle secondary school in Sesimbra and to 429 students studying in Canecas, selected as the control population. The average number of fish meals consumed by person was 4.1 and 3 per week in Sesimbra and Canecas, respectively. The subpopulations of high intake (PHI) corresponding to those ingesting 7 or more fish meals per week were also analyzed separately, with 17% of the students belonging to the PHI of Sesimbra versus 6.1% in Canecas. Socioeconomic aspects such as relative's professional involvement with fisheries correlated with the higher intakes in Sesimbra. Fish samples were collected in the dock of Sesimbra and total mercury (Hg) was determined by flow injection cold vapor atomic fluorescence spectroscopy (FI-CV-AFS). The mean value found for nonpredators was 0.035 microg/g. Dogfish specimens surpassed the legislated limit for predator species and increased the predators mean to 1 microg/g. The cross-sectional data were integrated with the fish analysis results to estimate the population exposure to MeHg. The indices of risk calculated for youth reached values of 4.5, demonstrating the existence of risk to a part of the population exceeding the provisional tolerable weekly intake (PTWI) level mandated by WHO (1.6 microg/kg bw). The results indicate that monitoring of Hg levels in fish is mandatory and counseling should be provided to populations at risk, encouraging them to prevent the risk.

The distribution, occurrence and environmental effect of mercury in Chinese coals

Mercury (Hg) is a toxic, persistent, and globally distributed pollutant due to its characteristic properties such as low melting and boiling points, conversion between chemical forms and participation in biological cycles. During combustion mercury in coal is almost totally emitted to the atmosphere. With a huge amount of coal consumed, coal combustion is one of the main anthropogenic sources of this element in the environment. In this study, Hg data of 1699 coal samples of China has been compiled, and the concentration, distribution, modes of occurrence, and the impact of Hg emissions on the environment are investigated. Most Chinese coals have Hg content in the range of 0.1 to 0.3 ppm, with an average of 0.19 ppm, which is slightly higher than the average Hg content of world coals and is close to that of the U.S. coals. The Hg content in coals varies in different coal basins, geological ages and coal ranks. The most likely mode of occurrences of Hg in high-sulfur and high Hg content coals is as solid solution in pyrite. But in low-sulfur coals, modes of occurrence of Hg are variable, and the organic-bound and sulfide-bound Hg may dominate. Silicate-bound Hg may be the main form in some coals because of magmatic intrusion. Mercury emissions during coal combustion have resulted in serious environmental contamination in China, particularly in the northeastern and southwestern China, where a high Hg content in the atmosphere occurs.

Fish consumption and bioindicators of inorganic mercury exposure

BACKGROUND

The direct and close relationship between fish consumption and blood and hair mercury (Hg) levels is well known, but the influence of fish consumption on inorganic mercury in blood (B-IHg) and in urine (U-Hg) is unclear.

OBJECTIVE

Examine the relationship between fish consumption, total, inorganic and organic blood Hg levels and urinary Hg concentration.

METHODS

A cross-sectional study was carried out on 171 persons from 7 riparian communities on the Tapajós River (Brazilian Amazon), with no history of inorganic Hg exposure from occupation or dental amalgams. During the rising water season in 2004, participants responded to a dietary survey, based on a seven-day recall of fish and fruit consumption frequency, and socio-demographic information was recorded. Blood and urine samples were collected. Total, organic and inorganic Hg in blood as well as U-Hg were determined by Atomic Absorption Spectrometry.

RESULTS

On average, participants consumed 7.4 fish meals/week and 8.8 fruits/week. Blood total Hg averaged 38.6+/-21.7 microg/L, and the average percentage of B-IHg was 13.8%. Average organic Hg (MeHg) was 33.6+/-19.4 microg/L, B-IHg was 5.0+/-2.6 microg/L, while average U-Hg was 7.5+/-6.9 microg/L, with 19.9% of participants presenting U-Hg levels above 10 microg/L. B-IHg was highly significantly related to the number of meals of carnivorous fish, but no relation was observed with non-carnivorous fish; it was negatively related to fruit consumption, increased with age, was higher among those who were born in the Tapajós region, and varied with community. U-Hg was also significantly related to carnivorous but not non-carnivorous fish consumption, showed a tendency towards a negative relation with fruit consumption, was higher among men compared to women and higher among those born in the region. U-Hg was strongly related to I-Hg, blood methyl Hg (B-MeHg) and blood total Hg (B-THg). The Odds Ratio (OR) for U-Hg above 10 microg/L for those who ate >4 carnivorous fish meals/week was 4.00 [1.83-9.20].

CONCLUSION

This study adds further evidence to a positive relation between fish consumption and IHg in both blood and urine, which may result from absorption of IHg from fish or from demethylation of MeHg. The findings support the importance of assessing IHg exposure in fish-eating communities. Further studies should examine the potential toxicity of IHg in heavy fish consumers.

Methylmercury exposure and health effects in humans: a worldwide concern

The paper builds on existing literature, highlighting current understanding and identifying unresolved issues about MeHg exposure, health effects, and risk assessment, and concludes with a consensus statement. Methylmercury is a potent toxin, bioaccumulated and concentrated through the aquatic food chain, placing at risk people, throughout the globe and across the socioeconomic spectrum, who consume predatory fish or for whom fish is a dietary mainstay. Methylmercury developmental neurotoxicity has constituted the basis for risk assessments and public health policies. Despite gaps in our knowledge on new bioindicators of exposure, factors that influence MeHg uptake and toxicity, toxicokinetics, neurologic and cardiovascular effects in adult populations, and the nutritional benefits and risks from the large number of marine and freshwater fish and fish-eating species, the panel concluded that to preserve human health, all efforts need to be made to reduce and eliminate sources of exposure.

Environmental mercury contamination in China: sources and impacts

This review article focused on the current status of mercury (Hg) contamination in different ecological compartments in China, and their possible environmental and health impacts, focusing on some major cities. Mercury emission from non-ferrous metals smelting (especially zinc smelting), coal combustion and miscellaneous activities (of which battery and fluorescent lamp production and cement production are the largest), contributed about 45%, 38% and 17%, respectively, to the total Hg emission based on the data of 1999. Mercury contamination is widespread in different ecological compartments such as atmosphere, soil and water. There is evidence showing bioaccumulation and biomagnification of Hg in aquatic food chains, with higher concentrations detected in carnivorous fish. In terms of human exposure to Hg, fish consumption is the major exposure pathway for residents living in coastal cities such as Hong Kong, but inhalation may be another major source, affecting human health in areas with severe atmospheric Hg, such as Guiyang City (Guizhou Province). The first case study indicated that after closure of the acetic acid plant 20 years at Songyuan City (Jilin Province), 16.7% of residents' hair still contained Hg concentration in excess of 1 mg/kg (the reference dosage value, RfD set by USEPA). The second case study indicated that the male residents of Hong Kong who consumed more than four or more meals of fish per week tended to contain higher Hg in their hair, which was linked to their subfertility. There is also increasing evidence showing that skin disorders and autism in Hong Kong children are related to their high Hg body loadings (hair, blood and urine), through prenatal methyl Hg exposure. There seems to be an urgent need to identify the sources of Hg, speciation and concentrations in different ecological compartments, which may lead to high body loadings in human beings. Adverse health effects of residents living in places with a higher background level of Hg, due to long-term exposure to chronic levels of Hg through oral intake should not be overlooked.

Novel reduction of mercury (II) by mercury-sensitive dissimilatory metal reducing bacteria

The dissimilatory metal reducing bacterium (DMRB) Shewanella oneidensis MR-1 reduces ionic mercury (Hg[II]) to elemental mercury (Hg[0]) by an activity not related to the MerA mercuric reductase. In S. oneidensis, this activity is constitutive and effective at Hg(II) concentrations too low to induce mer operon functions. Reduction of Hg(II) by MR-1 required the presence of electron donors and electron acceptors. Reduction occurred with oxygen or fumarate, but had the highest rate when ferric oxyhydroxide was used as a terminal electron acceptor. Geobacter sulfurreducens PCA and Geobacter metallireducens GS-15 reduced Hg(II) to Hg(0) with activity comparable to MR-1; however, neither the DMRB Anaeromyxobacter dehalogenans 2CP-C nor the nitrate reducer Pseudomonas stutzeri OX-1 reduced Hg(II) during growth. This discovery of constitutive mercury reduction among anaerobes has implications to the mobilization of mercury and production of methylmercury in anoxic environments.

A framework and information needs for the management of the risks from consumption of self-caught fish

Governmental agencies deal with the potential risk from consuming fish contaminated with toxic chemicals by issuing fish consumption advisories. Yet such advisories are often ignored by the general public, who continue to fish and consume self-caught fish that are the subject of advisories and are from contaminated waters. Further, people are often unaware of specific warnings (which species to avoid, who is vulnerable, when they are vulnerable). In this paper we propose a more inclusive framework for examining consumption behavior of self-caught fish and identify information needs for effective communication. We include not only the usual variables that are used for calculating risk from fish consumption (meal frequency, meal size, contaminant levels) but also other aspects of behavior that contribute to risk. These include attitudes (trust, risk aversion, environmental concerns), behavior (sources of information, cultural mores, personal preferences), exposure (physical proximity, ingestion rates, bioavailability, target tissues), contaminant levels, individual host differences, and hazards (levels of contaminants). We suggest that attitudes and behavior shape risk as much as exposure and hazards and that all four of these factors must be considered in risk management. Factors such as gender, age, pregnancy status, and nutrition all influence who is at risk, while other consumption factors affect these at-risk populations, including meals/week, meal size, cooking method, fish species and sizes eaten, and years of fish consumption. Similarly, contaminant levels in fish vary by fish species, fish size and age, part of the fish, and collection location. Elucidating the risk to individual consumers involves integrating this range of factors, and managing the risk likewise involves incorporating these factors. We suggest that development of appropriate advisories and compliance with advisories will occur only if managers, risk assessors, and public policy makers consider this whole range of factors and not just the traditional fish consumption rate (often underestimated) and contaminant levels in fish (often undersampled). Merely informing the public of contaminant levels or the risk from contaminants will not ensure a public that has enough information to make informed decision, or to be in compliance with consumption advisories, or to effect changes in consumption behavior where public health is at risk.