麻豆淫院

Researchers from Woods Hole Oceanographic Institution (WHOI) and Pohang University of Science and Technology (POSTECH) have traced the atmospheric journey of industrial mercury emissions from Asia into the open ocean food web. The new study, in Communications Earth & Environment, shows that more than half of the gaseous mercury emitted from Asian sources oxidizes into Hg虏鈦�, a reactive and bioavailable form of the pollutant.

This form is the precursor to methylmercury鈥攁 potent neurotoxin produced in seawater that builds up in top marine predators, such as tuna. It also poses a public health risk to those relying on seafood from the region.

"Zooplankton, located at the base of the marine food web, proves to be a powerful biomarker," said WHOI Marine Chemist Laura Motta, lead author of the study. "Not all mercury is available to marine organisms, but we were able to follow the path of bioavailable mercury. We did this by analyzing mercury isotopes in plankton to trace atmospheric processes and biogeochemical pathways of mercury."

The findings explain why mercury concentrations in Pacific tuna are elevated in waters near Asia, while levels drop off in more remote areas. The study also distinguishes between atmospheric mercury pollution and mercury introduced into the open ocean via coastal zones. Since some forms of mercury are more mobile and bioavailable than others, this research, and similar studies, will be essential for developing effective environmental regulations.

Sae Yun Kwon, an associate professor in the Environmental & Health Impact Assessment Lab at POSTECH and the corresponding author of the study, explained that "understanding how anthropogenic mercury travels through the environment and food webs will be critical to the effective evaluation of the United Nations Minamata Convention.

"This treaty is designed to protect ecosystems and human health from mercury exposure through monitoring, research, and policies. Knowing the degree of pollution and where it ends up is no longer enough. We also need to know where it starts, how it gets there, and in what form."

These insights challenge the traditional definition of mercury as a "global pollutant." While the term has emphasized the widespread diffusion of mercury, this new research shows that the sources and transport pathways of mercury are traceable and potentially more manageable. Not all mercury is equally mobile, and now, we are starting to see the difference.

"The study shows that an effective mercury policy must focus on reducing the bioavailable fraction, particularly gaseous elemental mercury, which is most likely to undergo long-range transport and conversion into toxic forms," Motta continued. "Proactively protecting marine environments from pollution is essential to prevent toxins from entering food webs, harming wildlife, and threatening human health."