Expanding perceptions of subsistence fish consumption: evidence of high commercial fish consumption and dietary mercury exposure in an urban coastal community

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

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

Joint Effects of Fragmentation and Mercury Contamination on Marsh Periwinkle (Littoraria irrorata) Movement

There are different ways contaminants can interact and enhance the effects of habitat fragmentation, such as modifying the movement of organisms. The present study tested the hypothesis that mercury exacerbates the effects of fragmentation by affecting the movement of the marsh periwinkle Littoraria irrorata and reducing the probability of snails crossing fragmented microlandscape experimental systems. How these changes could affect the search efficiency of organisms in the long term was assessed using hidden Markov models and random walks simulations. Bayesian nonlinear models were used to analyze the effects of fragmentation and contamination on the mean speed and mean directional change of organisms. Snail movement for control and two mercury-exposure treatments were recorded in microlandscapes with six different levels of habitat cover and three landscape replicates. The results indicated that exposed organisms had lower probabilities of crossing the landscape, reduced speed, and shifts in step length distributions. Both mercury exposure and habitat fragmentation affected the movement of the marsh periwinkle. Mercury exacerbated the effects of habitat fragmentation by affecting the cognition (e.g., route planning, orientation, and spatial learning) and movement of L. irrorata. Hence, the interaction of these stressors could further reduce the functional connectivity of landscapes and reduce the search efficiency of organisms. Environ Toxicol Chem 2022;41:1742-1753. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Mercury Levels and Risk Implications Through Fish Consumption on the Sinaloa Coasts (Gulf of California, Northwest Mexico)

Fish consumption is the major source of mercury to humans. Fetuses and children are the most sensitive groups of populations to the effects of mercury. Consequently, fish consumption by pregnant women, children, and women of childbearing age is of concern because of the effects of mercury exposure on human health. To assess mercury exposure in a population in northwest Mexico, the allowed daily consumption of fish (which indicates the maximum daily amount of fish that can be consumed without causing adverse noncarcinogenic effects) was calculated for the general population (GP) and fishing-related population (FRP). The studied groups for both sectors of the population were children A (3-10 years old), children B (11-15 years old), women of childbearing age (16-40 years old), and the rest of the population (men ≥16 years old, and women ≥41 years old). Mercury content in canned and frozen tuna, smoked marlin, tilapia, Pacific sierra, dolphinfish, and bullseye puffer ranged from 0.01 to 0.23 μg/g wet weight; none of the values were above the limit set by Mexico. Regarding mercury concentrations and rates of fish consumption, the GP consumes 1.7-2.7 times the allowed daily consumption, and the FRP consumes 1.6-3.9 that limit. The risk analysis showed the children A and B groups from the GP and adults of FRP to be the highest percentage of the population at risk (approximately 35%). These results highlight the need for adequate strategies that consider mercury exposure as part of public health policies associated with fish consumption in Mexico.

Mercury exposure as a function of fish consumption in two Asian communities in coastal Virginia, USA

Fish consumption and associated mercury exposure were explored for two Asian-dominated church communities in coastal Virginia and compared with that of two non-Asian church communities. Seafood-consumption rates for the Chinese (36.9 g/person/day) and Vietnamese (52.7 g/person/day) church communities were greater than the general United States fish-consumption rate (12.8 g/person/day). Correspondingly, hair mercury concentrations for people from the Chinese (0.52 µg/g) and the Vietnamese church (1.46 µg/g) were greater than the overall level for United States women (0.20 µg/g) but lower than the published World Health Organization exposure threshold (14 µg/g). A conventional regression model indicated a positive relationship between seafood consumption rates and hair mercury concentrations suggesting the importance of mercury exposure through seafood consumption. The annual-average daily methylmercury intake rate for the studied communities calculated by Monte Carlo simulations followed the sequence: Vietnamese community > Chinese community > non-Asian communities. Regardless, their daily methylmercury intake rates were all lower than the United States Environmental Protection Agency reference dose of 0.1 µg/kg body weight-day. In conclusion, fish-consumption patterns differed among communities, which resulted in different levels of mercury exposure. The greater seafood and mercury ingestion rates of studied Asian groups compared with non-Asian groups suggest the need for specific seafood consumption advice for ethnic communities in the United States. Otherwise the health benefits from fish consumption could be perceived as trivial compared with the ill-defined risk of mercury exposure.

Mercury in fish and adverse reproductive outcomes: results from South Carolina

Background

Mercury is a metal with widespread distribution in aquatic ecosystems and significant neurodevelopmental toxicity in humans. Fish biomonitoring for total mercury has been conducted in South Carolina (SC) since 1976, and consumption advisories have been posted for many SC waterways. However, there is limited information on the potential reproductive impacts of mercury due to recreational or subsistence fish consumption.

Methods

To address this issue, geocoded residential locations for live births from the Vital Statistics Registry (1995–2005, N = 362,625) were linked with spatially interpolated total mercury concentrations in fish to estimate potential mercury exposure from consumption of locally caught fish. Generalized estimating equations were used to test the hypothesis that risk of low birth weight (LBW, <2,500 grams) or preterm birth (PTB, <37 weeks clinical gestation) was greater among women living in areas with elevated total mercury in fish, after adjustment for confounding. Separate analyses estimated term LBW and PTB risks using residential proximity to rivers with fish consumption advisories to characterize exposure.

Results

Term LBW was more likely among women residing in areas in the upper quartile of predicted total mercury in fish (odds ratio [OR] = 1.04; 95% confidence interval [CI]: 1.00-1.09) or within 8 kilometers of a river with a ‘do not eat’ fish advisory (1.05; 1.00-1.11) compared to the lowest quartile, or rivers without fish consumption restrictions, respectively. When stratified by race, risks for term LBW or PTB were 10-18% more likely among African-American (AA) mothers living in areas with the highest total fish mercury concentrations.

Conclusions

To our knowledge, this is the first study to examine the relationship between fish total mercury concentrations and adverse reproductive outcomes in a large population-based sample that included AA women. The ecologic nature of exposure assessment in this study precludes causal inference. However, the results suggest a need for more detailed investigations to characterize patterns of local fish consumption and potential dose–response relationships between mercury exposure and adverse reproductive outcomes, particularly among AA mothers.

An ecologically framed mercury survey of finfish of the lower Chesapeake Bay

Total mercury (THg) and methylmercury (MHg) concentrations and determents of mercury (Hg) accumulation were examined for muscle tissues of 10 finfish from the lower Chesapeake Bay (LCB) and its tributaries. There was no suggestion of potential human harm from Hg due to LCB fish consumption: None of the sampled fish had THg concentrations approaching the United States Environmental Protection Agency human health screening value. Hg concentrations in different fish species generally increased with the increasing stable isotope of nitrogen 15 (δ(15)N) but not the stable isotope of carbon 13 (δ(13)C), thus suggesting that trophic position but not dietary carbon source is a dominant determinant. An MHg biomagnification model was built to estimate a food web magnification factor of approximately 10-fold increase per trophic level. Based on otolith strontium-to-calcium ratios, Atlantic croaker inhabiting less saline waters might accumulate more Hg than those inhabiting more saline waters. The SAS mixed procedure identified significant positive intraspecies relationships between MHg concentration and δ(13)C for summer flounder, weakfish, American eel, Atlantic croaker, and spot.

Dietary nutrient and food intake and their relations with serum heavy metals in osteopenic and osteoporotic patients

Several studies have reported that heavy metals have a relation with osteoporosis and osteoporotic fractures. In this study, we investigated the association between heavy metal exposure status, as assessed by serum major heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg) and bone mineral density (BMD) status among Korean adults. A total of 64 adults participated in this study and were assigned to one of three study groups based on the T-score of spine BMD: a normal group (n = 21, T-score > -1), osteopenia group (n = 29, -2.5 < T-score ≤ -1) and osteoporosis group (n = 14, T-score ≤ -2.5). We also assessed serum levels of heavy metals (Pb, Cd and Hg) by using atomic absorption spectrometer (AAS) and daily nutrient and food intakes for 3 days by using 24-hr recall method in the subjects. The mean age was significantly higher in the osteoporosis group compared with the osteopenia and normal groups (p < 0.001). There was no significant difference in serum levels of Pb, Cd and Hg among the three groups after adjusting for age. Daily intakes of energy, nutrients were not significantly different among the three groups. The osteoporosis group consumed significantly higher fish and shellfish than the other groups (p < 0.05). In the correlation analysis controlling for age, sex, BMI, and BMD status, the serum Cd level was significantly negatively correlated with intake of cereals, milks and total food. In summary, we did not find a direct association between serum heavy metal levels and BMD status. However, negative relationships were found between serum heavy metal levels and intake of some foods.