"Antimony is an emergent contaminant," said IU Bloomington Ph.D. student Faye Liu, the paper's lead author. "People have not paid enough attention to it."
Used in small quantities, antimony has a wide variety of applications -- from hardening the lead in bullets and improving battery performance to combating malaria.
Little is known about antimony's toxicity, in part because the metalloid element is usually found at low, parts-per-billion concentrations in natural environments. At Xikuangshan, Liu and her colleagues found that aqueous antimony concentrations could be as high 11 parts per million, 1,000 times the antimony levels found in uncontaminated water.
The alarming circumstances at Xikuangshan present an opportunity to understand what happens to antimony, geologically and chemically, when large quantities of it are introduced to the environment. That knowledge will be useful to investigations of antimony contamination near factories and military bases around the world.
The U.S. Environmental Protection Agency and similar regulatory agencies in Europe operate under the assumption that antimony's properties are similar to those of arsenic, another element in antimony's chemical group.
"That will need to change," said IU Bloomington geologist Chen Zhu, Liu's advisor and the project's principal investigator. "We saw that antimony behaves very differently from arsenic -- antimony oxidizes much more quickly than arsenic when exposed."
The vast majority of antimony the scientists isolated at Xikuangshan was of the "V" type, an oxidation state in which the metal has given up five electrons. It is believed V is the least toxic of the three oxidation states of which antimony is capable (I, III and V). It is not known whether antimony-V's relatively diminished toxicity is upended at Xikuangshan by its overwhelming presence.
Land within and around the mining area is used for farming. The drinking water plant for local residents was built in the mining area. Zhu says health problems are common at Xikuangshan, possibly the result of antimony intoxication.
Zhu says he is discussing a possible collaboration with IU School of Medicine toxicologist Jim Klaunig. Researchers would return to Xikuangshan to determine whether the elevated antimony can be tied to acute and chronic health problems among those who live in the vicinity. Another possible study group might be those Chinese who live downstream of Xikuangshan along the Qing River.
As part of their Environmental Geochemistry and Health study, Zhu and scientists from the Chinese Academy of Sciences conducted field work at Xikuangshan in 2007, drawing multiple water samples from 18 different sample sites. Samples were shipped back to Bloomington for atomic fluorescence spectroscopic analysis and to Alberta for inductively coupled plasma mass spectroscopy analysis. The scientists learned antimony-III was rare, beyond detection or present at trace levels. The near totality of antimony in each water sample was antimony-V.
The Xikuangshan antimony mine is the world's largest. Since antimony mining began there more than 200 years ago, mine production has increased steadily to the present day. Today, Xikuangshan produces 60 percent of the world's antimony.
While Zhu was on sabbatical leave in 2008, Faye Liu was advised by IU Bloomington biogeochemist and inaugural Provost's Professor Lisa Pratt. Zhu and Pratt recently began a joint project to learn more about the biogeochemistry of antimony. The scientists' antimony research complements their concurrent NSF-funded research on arsenic.
IU Bloomington geologists Claudia Johnson and Erika Elswick, both participants in the Environmental Geochemistry and Health study, have also taken seawater samples from the Caribbean. Liu is investigating the samples' antimony content.
Also contributing to the research were University of Alberta environmental toxicologist X. Chris Le and his students, Anthony McKnight-Whitford (Ph.D.) and Yunlong Xia (M.S.), and Chinese Academy of Sciences geochemist Fengchang Wu. The research was supported by the China Scholarship Council and Indiana University.
To speak with Zhu or Liu, please contact David Bricker, University Communications, at 812-856-9035 or firstname.lastname@example.org.
"Antimony speciation and contamination of waters in the Xikuangshan antimony mining and smelting area, China," Environmental Geochemistry and Health, by Faye Liu, X. Chris Le, Anthony McKnight-Whitford, Yunlong Xia, Fengchang Wu, Erika Elswick, Claudia C. Johnson, and Chen Zhu (early access online)
David Bricker | Newswise Science News
Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter
16.08.2018 | National Science Foundation
Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide
15.08.2018 | University of Washington
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences