Mercury cycling and human health concerns in remote ecosystems in the Americas
Bibliographic record
Abstract
Fish constitutes a praised—and sometimes irreplaceable—component of the daily diet for numerous communities throughout the Americas. These populations can be exposed to mercury (Hg)—ubiquitous in fish flesh—to levels potentially harmful to their health. Mercury is subjected to various chemical transformations once released to the environment. From diffuse loading on land and waters to accumulation in the aquatic food web, this paper draws a general picture of the main processes influencing the Hg cycle in different ecozones. Contrarily to other pollutants, the amount of Hg found in fish tissues is not clearly related to the extent of Hg loading in a given ecosystem. In the Arctic, the sudden stripping of gaseous elemental Hg from the atmosphere—known as the Hg depletion events—and its subsequent transformation into methylmercury (MeHg) seems to be one of the driving force behind Hg accumulation in freshwater aquatic organisms and marine mammals. In boreal environments, numerous watershed-based processes influence the transport and methylation of Hg deposited from atmospheric source and selectively control the amount of MeHg transferred from source to fish. In the tropics, small-scale gold mining operations have induced the release of considerable amount of Hg to the environment. However, the extensive deforestation of the tropical forest and the subsequent erosion and lixiviation of land-deposited Hg down to tropical rivers appears to have a greater impact on the observed wide-scale fish Hg contamination. Mercury accumulation in remote ecosystems do represent a significant and complex environmental issue, considering: (a) the high levels of Hg monitored in fish and marine mammals flesh; (b) the large-scale occurrence of such worrying Hg bioaccumulation patterns; (c) the extensive use of aquatic resources by numerous remote communities; (d) the fact that this issue shall persist at least on the mid-term, even if strong measures are taken to lessen Hg anthropogenic loadings to the global atmosphere. Although there are no simple answers to the potential threats to human health caused by Hg accumulation, several political actions to lessen human exposure to Hg are possible and are discussed here.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".