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Methylmercury exposure in a subsistence fishing community in Lake Chapala, Mexico: an ecological approach.

Trasande L, Cortes JE, Landrigan PJ, Abercrombie MI, Bopp RF, Cifuentes E - Environ Health (2010)

Bottom Line: Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm).Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers.Consumption of carp appears to contribute significantly to body burden in this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Community and Preventive Medicine, Mount Sinai School of Medicine, 1 Gustave L Levy Place, Box 1057, New York, NY 10029, USA.

ABSTRACT

Background: Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated.

Methods: Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age.

Results: Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm). Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations.

Conclusions: Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.

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Histogram of Hair Mercury Levels in Population Studied (Outlier of 141 ppm Excepted).
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Figure 2: Histogram of Hair Mercury Levels in Population Studied (Outlier of 141 ppm Excepted).

Mentions: The distribution of hair mercury concentrations was found to be positively skewed (see Figure 2), with one outlier (141 ppm, confirmed on multiple analyses). This outlier was not included in bivariate and multivariate analysis to identify predictors of hair mercury concentrations. It should be noted, however that a similar "outlier," a mother with 86 ppm total hair mercury, was found in a New Zealand cohort [32]. The NHANES study reported three exceptionally high hair mercury concentrations, all in Mexican-Americans, 849 ppm in a woman, 415.2 ppm in a one-year old child, and 109.8 ppm in a three-year old [31].


Methylmercury exposure in a subsistence fishing community in Lake Chapala, Mexico: an ecological approach.

Trasande L, Cortes JE, Landrigan PJ, Abercrombie MI, Bopp RF, Cifuentes E - Environ Health (2010)

Histogram of Hair Mercury Levels in Population Studied (Outlier of 141 ppm Excepted).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2820022&req=5

Figure 2: Histogram of Hair Mercury Levels in Population Studied (Outlier of 141 ppm Excepted).
Mentions: The distribution of hair mercury concentrations was found to be positively skewed (see Figure 2), with one outlier (141 ppm, confirmed on multiple analyses). This outlier was not included in bivariate and multivariate analysis to identify predictors of hair mercury concentrations. It should be noted, however that a similar "outlier," a mother with 86 ppm total hair mercury, was found in a New Zealand cohort [32]. The NHANES study reported three exceptionally high hair mercury concentrations, all in Mexican-Americans, 849 ppm in a woman, 415.2 ppm in a one-year old child, and 109.8 ppm in a three-year old [31].

Bottom Line: Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm).Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers.Consumption of carp appears to contribute significantly to body burden in this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Community and Preventive Medicine, Mount Sinai School of Medicine, 1 Gustave L Levy Place, Box 1057, New York, NY 10029, USA.

ABSTRACT

Background: Elevated concentrations of mercury have been documented in fish in Lake Chapala in central Mexico, an area that is home to a large subsistence fishing community. However, neither the extent of human mercury exposure nor its sources and routes have been elucidated.

Methods: Total mercury concentrations were measured in samples of fish from Lake Chapala; in sections of sediment cores from the delta of Rio Lerma, the major tributary to the lake; and in a series of suspended-particle samples collected at sites from the mouth of the Lerma to mid-Lake. A cross-sectional survey of 92 women ranging in age from 18-45 years was conducted in three communities along the Lake to investigate the relationship between fish consumption and hair mercury concentrations among women of child-bearing age.

Results: Highest concentrations of mercury in fish samples were found in carp (mean 0.87 ppm). Sediment data suggest a pattern of moderate ongoing contamination. Analyses of particles filtered from the water column showed highest concentrations of mercury near the mouth of the Lerma. In the human study, 27.2% of women had >1 ppm hair mercury. On multivariable analysis, carp consumption and consumption of fish purchased or captured from Lake Chapala were both associated with significantly higher mean hair mercury concentrations.

Conclusions: Our preliminary data indicate that, despite a moderate level of contamination in recent sediments and suspended particulate matter, carp in Lake Chapala contain mercury concentrations of concern for local fish consumers. Consumption of carp appears to contribute significantly to body burden in this population. Further studies of the consequences of prenatal exposure for child neurodevelopment are being initiated.

Show MeSH
Related in: MedlinePlus