Human perturbations to mercury in global rivers

Area of Science:

• Environmental Science
• Toxicology
• Geochemistry

Background:

• Mercury compounds are neurotoxins, with human health risks primarily from fish consumption.
• Riverine mercury concentrations and export to oceans have increased significantly since the Industrial Revolution.
• Understanding historical mercury patterns is crucial for evaluating environmental policies.

Purpose of the Study:

• To develop a global model simulating preindustrial riverine total mercury.
• To assess human impacts on riverine mercury by comparing historical and present-day conditions.
• To establish a baseline for riverine mercury levels and inform restoration targets.

Main Methods:

• Global modeling of riverine total mercury.
• Simulation of preindustrial mercury transport.
• Comparison of modeled preindustrial conditions with present-day mercury levels.

Main Results:

• Preindustrial global rivers transported approximately 390 megagrams of mercury annually to the oceans.
• Human activities have increased riverine mercury budgets by two to three times in the present day.
• Significant spatial variability exists in historical and current mercury transport.

Conclusions:

• Riverine mercury levels show rapid responses to human perturbations.
• Findings provide a baseline for global riverine mercury restoration targets.
• Riverine mercury concentrations can serve as indicators for mercury pollution governance effectiveness.