Charles N Alpers
Since 1991, as a Research Chemist with USGS, Dr. Alpers has led numerous water-quality investigations involving the environmental effects of historical mining.
This work has included research on acid mine drainage at the Iron Mountain Superfund site, including documentation of negative-pH water and associated sulfate minerals. Since 1999, he has been lead scientist for several multi-disciplinary studies regarding mercury contamination, transport, and bioaccumulation associated with historical gold mining in the Sierra Nevada and Coast Ranges of California. He is also investigating arsenic bioavailability and bioaccessibility in gold-mine waste at the Empire Mine in Grass Valley, California as part of a multi-disciplinary team involving USGS and non-USGS scientists.
The overarching theme of Dr. Alpers' research is the environmental geochemistry of metal contamination from historical mining. A secondary theme is the use of mineral deposits and areas contaminated by mining as laboratories for process-oriented research. His career has evolved from an emphasis on acid mine drainage (late 1980s to 2000) to an emphasis on mercury (since 2000) with growing interests in wetlands, arsenic, and lead.
Science and Products
Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA
Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter
Mercury cycling in agricultural and managed wetlands, Yolo Bypass, California: Spatial and seasonal variations in water quality
Biogenic iron mineralization at Iron Mountain, CA with implications for detection with the Mars Curiosity rover
Mercury cycling in agricultural and managed wetlands: a synthesis of methylmercury production, hydrologic export, and bioaccumulation from an integrated field study
Methylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone
Arsenic associated with historical gold mining in the Sierra Nevada foothills: Case study and field trip guide for Empire Mine State Historic Park, California
Vibrational, X-ray absorption, and Mössbauer spectra of sulfate minerals from the weathered massive sulfide deposit at Iron Mountain, California
Thermodynamic properties for arsenic minerals and aqueous species
The environmental geochemistry of Arsenic – An overview
Preface
Raman spectroscopy of efflorescent sulfate salts from Iron Mountain Mine Superfund Site, California
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Methylmercury production in sediment from agricultural and non-agricultural wetlands in the Yolo Bypass, California, USA
As part of a larger study of mercury (Hg) biogeochemistry and bioaccumulation in agricultural (rice growing) and non-agricultural wetlands in California's Central Valley, USA, seasonal and spatial controls on methylmercury (MeHg) production were examined in surface sediment. Three types of shallowly-flooded agricultural wetlands (white rice, wild rice, and fallow fields) and two types of managed (AuthorsMark Marvin-DiPasquale, Lisamarie Windham-Myers, Jennifer L. Agee, Evangelos Kakouros, Le H. Kieu, Jacob A. Fleck, Charles N. Alpers, Craig A. StrickerConcurrent photolytic degradation of aqueous methylmercury and dissolved organic matter
Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercuryAuthorsJacob A. Fleck, Gary W. Gill, Brian A. Bergamaschi, Tamara E.C. Kraus, Bryan D. Downing, Charles N. AlpersMercury cycling in agricultural and managed wetlands, Yolo Bypass, California: Spatial and seasonal variations in water quality
The seasonal and spatial variability of water quality, including mercury species, was evaluated in agricultural and managed, non-agricultural wetlands in the Yolo Bypass Wildlife Area, an area managed for multiple beneficial uses including bird habitat and rice farming. The study was conducted during an 11-month period (June 2007 to April 2008) that included a summer growing season and flooded conAuthorsCharles N. Alpers, Jacob A. Fleck, Mark C. Marvin-DiPasquale, Craig A. Stricker, Mark Stephenson, Howard E. TaylorBiogenic iron mineralization at Iron Mountain, CA with implications for detection with the Mars Curiosity rover
(Introduction) Microbe-mineral interactions and biosignature preservation in oxidized sulfidic ore bodies (gossans) are prime candidates for astrobiological study. Such oxidized iron systems have been proposed as analogs for some Martian environments. Recent studies identified microbial fossils preserved as mineral-coated filaments. This study documents microbially-mediated mineral biosignatures iAuthorsAmy J. Williams, Dawn Y. Sumner, Charles N. Alpers, Kate M. Campbell, D. Kirk NordstromMercury cycling in agricultural and managed wetlands: a synthesis of methylmercury production, hydrologic export, and bioaccumulation from an integrated field study
With seasonal wetting and drying, and high biological productivity, agricultural wetlands (rice paddies) may enhance the conversion of inorganic mercury (Hg(II)) to methylmercury (MeHg), the more toxic, organic form that biomagnifies through food webs. Yet, the net balance of MeHg sources and sinks in seasonal wetland environments is poorly understood because it requires an annual, integrated asseAuthorsLisamarie Windham-Myers, Jacob A. Fleck, Joshua T. Ackerman, Mark C. Marvin-DiPasquale, Craig A. Stricker, Wesley A. Heim, Philip A.M. Bachand, Collin A. Eagles-Smith, Gary Gill, Mark Stephenson, Charles N. AlpersMethylmercury production in and export from agricultural wetlands in California, USA: the need to account for physical transport processes into and out of the root zone
Concentration and mass balance analyses were used to quantify methylmercury (MeHg) loads from conventional (white) rice, wild rice, and fallowed fields in northern California's Yolo Bypass. These analyses were standardized against chloride to distinguish transport pathways and net ecosystem production (NEP). During summer, chloride loads were both exported with surface water and moved into the rooAuthorsPhilip A.M. Bachand, Sandra M. Bachand, Jacob A. Fleck, Charles N. Alpers, Mark Stephenson, Lisamarie Windham-MyersArsenic associated with historical gold mining in the Sierra Nevada foothills: Case study and field trip guide for Empire Mine State Historic Park, California
The Empire Mine, together with other mines in the Grass Valley mining district, produced at least 21.3 million troy ounces (663 tonnes) of gold (Au) during the 1850s through the 1950s, making it the most productive hardrock Au mining district in California history (Clark 1970). The Empire Mine State Historic Park (Empire Mine SHP or EMSHP), established in 1975, provides the public with an opportunAuthorsCharles N. Alpers, Perry A Myers, Daniel Millsap, Tamsen B RegnierVibrational, X-ray absorption, and Mössbauer spectra of sulfate minerals from the weathered massive sulfide deposit at Iron Mountain, California
The Iron Mountain Mine Superfund site in California is a prime example of an acid mine drainage (AMD) system with well developed assemblages of sulfate minerals typical for such settings. Here we present and discuss the vibrational (infrared), X-ray absorption, and Mössbauer spectra of a number of these phases, augmented by spectra of a few synthetic sulfates related to the AMD phases. The mineralAuthorsJuraj Majzlan, Charles N. Alpers, Christian Bender Koch, R. Blaine McCleskey, Satish B.C. Myneni, John M. NeilThermodynamic properties for arsenic minerals and aqueous species
Quantitative geochemical calculations are not possible without thermodynamic databases and considerable advances in the quantity and quality of these databases have been made since the early days of Lewis and Randall (1923), Latimer (1952), and Rossini et al. (1952). Oelkers et al. (2009) wrote, “The creation of thermodynamic databases may be one of the greatest advances in the field of geochemistAuthorsD. Kirk Nordstrom, Juraj Majzlan, Erich KönigsbergerThe environmental geochemistry of Arsenic – An overview
Arsenic is one of the most prevalent toxic elements in the environment. The toxicity, mobility, and fate of arsenic in the environment are determined by a complex series of controls dependent on mineralogy, chemical speciation, and biological processes. The element was first described by Theophrastus in 300 B.C. and named arsenikon (also arrhenicon; Caley and Richards 1956) referring to its “potenAuthorsRobert J. Bowell, Charles N. Alpers, Heather E. Jamieson, D. Kirk Nordstrom, Juraj MajzlanPreface
Arsenic is perhaps history’s favorite poison, often termed the “King of Poisons” and the “Poison of Kings” and thought to be the demise of fiction’s most famous ill-fated lovers. The toxic nature of arsenic has been known for millennia with the mineral realgar (AsS), originally named “arsenikon” by Theophrastus in 300 B.C.E. meaning literally “potent.” For centuries it has been used as rat poisonAuthorsRobert J. Bowell, Charles N. Alpers, Heather E. Jamieson, D. Kirk Nordstrom, Juraj MajzlanRaman spectroscopy of efflorescent sulfate salts from Iron Mountain Mine Superfund Site, California
The Iron Mountain Mine Superfund Site near Redding, California, is a massive sulfide ore deposit that was mined for iron, silver, gold, copper, zinc, and pyrite intermittently for nearly 100 years. As a result, both water and air reached the sulfide deposits deep within the mountain, producing acid mine drainage consisting of sulfuric acid and heavy metals from the ore. Particularly, the drainageAuthorsPablo Sobron, Charles N. Alpers - News