Dataset Information

Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

ABSTRACT: Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO) Expert Committee of Food Additives (JECFA)'s Provisional Tolerable Weekly Intake (PTWI); and (2), to measure the mercury levels of paco (Piaractus brachypomus) fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight). We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred) in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute to human mercury exposure. More research is needed on human health risks associated with ASGM to discern occupational, residential, and nutritional exposure, especially through tracking temporal changes in mercury levels as fish ponds age, and assessing levels in different farmed fish species. Additionally, research is needed to definitively determine that elevated mercury levels in humans and fish result from the elemental mercury from mining, rather than from a different source, such as the mercury released from soil erosion during deforestation events from mining or other activities.

SUBMITTER: Langeland AL

PROVIDER: S-EPMC5369138 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

Langeland Aubrey L AL Hardin Rebecca D RD Neitzel Richard L RL

International journal of environmental research and public health 20170314 3

Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participa ...[more]

PMID: 28335439

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Project description:BackgroundFew birth cohorts in South America evaluate the joint effect of minerals and toxic metals on neonatal health. In Madre de Dios, Peru, mercury exposure is prevalent owing to artisanal gold mining, yet its effect on neonatal health is unknown.ObjectivesWe aimed to determine whether toxic metals are associated with lower birth weight and shorter gestational age independently of antenatal care and other maternal well-being factors.MethodsData are from the COhorte de NAcimiento de MAdre de Dios (CONAMAD) birth cohort, which enrolled pregnant women in Madre de Dios prior to their third trimester and obtained maternal and cord blood samples at birth. We use structural equation models (SEMs) to construct latent variables for the maternal metals environment (ME) and the fetal environment (FE) using concentrations of calcium, iron, selenium, zinc, magnesium, mercury, lead, and arsenic measured in maternal and cord blood, respectively. We then assessed the relationship between the latent variables ME and FE, toxic metals, prenatal visits, hypertension, and their effect on gestational age and birth weight.ResultsAmong 198 mothers successfully enrolled and followed at birth, 29% had blood mercury levels that exceeded the U.S. Centers for Disease Control and Prevention threshold of 5.8μg/L and 2 mothers surpassed the former 5-μg/dL threshold for blood lead. The current threshold value is 3.5μg/dL. Minerals and toxic metals loaded onto ME and FE latent variables. ME was associated with FE (β=0.24; 95% CI: 0.05, 0.45). FE was associated with longer gestational age (β=2.31; 95% CI: -0.3, 4.51) and heavier birth weight. Mercury exposure was not directly associated with health outcomes. A 1% increase in maternal blood lead shortened gestational age by 0.05 d (β=-0.75; 95% CI: -1.51, -0.13), which at the 5-μg/dL threshold resulted in a loss of 3.6 gestational days and 76.5g in birth weight for newborns. Prenatal care visits were associated with improved birth outcomes, with a doubling of visits from 6 to 12 associated with 5.5 more gestational days (95% CI: 1.6, 9.4) and 319g of birth weight (95% CI: 287.6, 350.7).DiscussionMaternal lead, even at low exposures, was associated with shorter gestation and lower birth weight. Studies that focus only on harmful exposures or nutrition may mischaracterize the dynamic maternal ME and FE. SEMs provide a framework to evaluate these complex relationships during pregnancy and reduce overcontrolling that can occur with linear regression. https://doi.org/10.1289/EHP10557.

Project description:Madre de Dios, a southern state in the Peruvian Amazon basin, has experienced rapid development as well as an influx of migrants since the construction of the Interoceanic Highway (IOH) connecting Brazil, Bolivia, and the Peruvian coast. We explored perceptions of migration and development in up to eight communities along the IOH in Madre de Dios following construction of the highway.We conducted a multiple methods study involving focus group (FG) discussions and interviews with key informants (KIs) in eight communities in Madre de Dios. The data was used to develop and apply a survey on demographics, financial, personal, social, human, and physical capital in four communities between February 2014 and March 2015.We conducted 12 FGs and 34 KI interviews. A total of 522 people participated in the survey. Comparing migrants (those who had moved to the area after construction of the IOH) and non-migrants, we found no difference in food security or access to health services. The majority (67.6%) of respondents from both groups reported that illness was their primary threat to well-being. Non-migrants owned more land than migrants (p?<?0.001), were more likely to have piped water directly in their home (p?=?0.046), and were more likely to participate in community groups (p?=?0.012). Looking at perceptions about migrants, KIs and FGs discussed both positive perceptions of migrants (increased cultural exchange and new technology) and negative perceptions (increased drugs and alcohol in their communities and a lack of investment in the community). Both migrants and non-migrants reported trusting the local government more than the national government.Although we hypothesized that migrants would have decreased access to food, water, health services, and land relative to non-migrants, our results show that the only significant differences were in land ownership and water access. Efforts to improve community infrastructure should be carried out at the local level and focus on improving issues reported by both groups, such as potable water, sewage, and increased access to health services. Furthermore, an emphasis on community cohesion, ensuring land rights, and increasing long-term job opportunities should help ease tensions between migrants and non-migrants.

Dataset Information

Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

Publications

Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

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