Karen Murray
Karen J. Murray, Ph.D.
Managing Scientist
Environmental & Earth Sciences

Dr. Murray is a biogeochemist with more than 15 years of experience investigating the fate and transport of contaminants in environmental systems. She specializes in the interactions between microorganisms and chemicals, focusing on the reactions which may alter the potential toxicity or mobility of the contaminant.

Dr. Murray has experience on a variety projects related to the fate of metals and petroleum products in the environment, including biodegradation and forensics applications. In particular, she has provided technical consulting on cases of mercury contamination, focusing on the complex chemical and biological reactions that control the methylation, and therefore toxicity of this metal. She has participated in the design and implementation of field and laboratory studies to determine the behavior of organic and inorganic chemicals in complex environmental media as well as provided support in related litigation matters. Her background in analytical chemistry allows her to evaluate and interpret large environmental data sets for a variety of chemicals.

Based on her academic research, Dr. Murray has published peer-reviewed papers on the potential for biological oxidation of Cr(III) to the more toxic Cr(VI) in marine and freshwater systems, as well as biological Mn oxidation, Co oxidation and Hg methylation. She has experience in field sampling in marine, freshwater and soil systems, including acting as chief scientist for ship-based marine sampling. Her analytical expertise includes aerobic and anaerobic microbial culturing techniques, electrochemical and spectroscopic chemical analyses and molecular biological methods.


  • Ph.D., Oceanography (Geochemistry), University of California, San Diego, 2005
  • B.S., Environmental Engineering Science, Massachusetts Institute of Technology (MIT), 1999
  • Recipient of the Environmental Protection Agency STAR graduate fellowship


Murray KJ, Webb SM, Bargar JR, Tebo BM. Indirect oxidation of Co(II) in the presence of the marine Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1. Applied and Environmental Microbiology 2007; 73(21):6905–6909.

Murray KJ, Tebo BM. Cr(III) is indirectly oxidized by the Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1. Environmental Science and Technology 2007; 41:528–533.

Glazer BT, Luther III GW, Konovalov SK, Friederich GE, Nuzzio DB, Trouwborst RE, Tebo BM, Clement B, Murray K, Romanov AS. Documenting the suboxic zone of the Black Sea via high-resolution real-time redox profiling. Deep-Sea Research 2006; 53:1740–1755.

Murray KJ, Mozafarzadeh ML, Tebo BM. Cr(III) oxidation and Cr toxicity in cultures of the manganese(II)-oxidizing Pseudomonas putida strain GB-1. Geomicrobiology Journal 2005; 22:151–159.

Tebo BM, Bargar JR, Clement BG, Dick GJ, Murray KL, Parker D, Verity R, Webb SM. Biogenic manganese oxides: Properties and mechanisms of formation. Annual Review of Earth and Planetary Sciences 2004; 32:287–328.

Konovalov SK, Luther GW, Friedrich GE, Nuzzio DB, Tebo BM, Murray JW, Oguz T, Glazer B, Trouwborst RE, Clement B, Murray KJ, Romanov AS. Lateral injection of oxygen with the Bosporus plume—Fingers of oxidizing potential in the Black Sea. Limnology and Oceanography 2003; 48(6):2369–2376.

Jay JA, Murray KJ, Gilmour CC, Mason RP, Morel FMM, Roberts AL, Hemond HF. Mercury methylation by Desulfovibrio desulfuricans ND132 in the presence of polysulfides. Applied and Environmental Microbiology 2002; 68(11):5741–5745.

Published Abstracts

Murray KJ, Tebo BM. Active bacterial Mn(II)-oxidation accelerates Cr(III) oxidation compared to abiotic oxidation by Mn minerals. Geochimica et Cosmochimica Acta 2005; 69(10):A456–A456 Suppl. S.

Murray KJ, Tebo BM. Cr(III) is indirectly oxidized by the Mn(II)-oxidizing bacterium Bacillus sp. Strain SG-1. Abstracts of Papers of the American Chemical Society 2005; 228:U896-U896 089-Geoc Part 1.

Murray KJ, Mozafarzadeh ML, Tebo BM. Role of manganese(II)-oxidizing bacteria in chromium (III) oxidation. Abstracts of papers of the American Chemical Society 2004; 227:U1212-U1212 124-Geoc Part 1.

Book Chapter

Konovalov SK, Murray JW, Luther GW, Buesseler KO, Friedrich G, Tebo BM, Samodurov AS, Gregoire M, Ivanov LI, Romanov AS, Clement B, Murray K. Oxygen fluxes, redox processes and the suboxic zone in the Black Sea. In: Oceanography of the Eastern Mediterranean and Black Sea: Similarities and Differences of Two Interconnected Basins. Yilmaz A (ed), Tübitak Publishers, pp. 566–577, Ankara, Turkey, 2003.

Prior Experience

Postdoctoral Researcher, Soil and Environmental Biogeochemistry Lab, Stanford University, 2005–2007

Professional Affiliations

American Chemical Society

American Geophysical Union

Project Experience


Evaluated a patented treatment method for the stabilization of cadmium and lead in fly ash from a waste-to-energy facility and the potential for remobilization under landfill conditions for a client operating a landfill. The goal of this work was to understand the cause of regulatory exceedances reported by the WTE operator. Project included an evaluation of the chemistry of the treatment method, an investigation of the specific laboratory methods used to confirm stabilization and a field investigation of the landfilled waste to evaluate landfill conditions.

Evaluated sources of mercury to river sediments using mercury stable isotope techniques in support of an expert witness report.

For a major oil company, worked with a team of chemists, hydrologists, ecologists and toxicologists to develop an ecological and human health risk assessment of mercury emissions from an on-shore gas processing facility. Specifically, was responsible for the chapters associated with the chemical and biological fate of deposited mercury.

Assisted in the preparation of a report regarding the impact of a proposed urban chilled water system which would discharge to a lake with historical mercury contamination. Specifically was responsible for the development of a chapter to address the potential chemical changes resulting from the discharge of a variable flow of potable water to one of the tributaries that discharges into the lake and any possible effects of the discharge on remediation efforts.

Monitored the published literature and summarized new mercury stable isotope studies which were provided as periodic reports to a client considering this technique to study mercury-contaminated sediments. 

Used traditional stable isotopes (carbon, nitrogen) and mercury measurements to analyze the food web associated with a lake with historical mercury contamination. In addition to performing the data analysis, worked with the laboratory to acquire the data and validated the results received. 

Coordinated laboratory analysis of sediment and water samples associated with a site potentially impacted by metals and other contaminants from bauxite ore processing and analyzed the resulting data using various environmental forensic techniques. Assisted with expert report and rebuttal preparation. 

Reviewed available documents associated with the remedial activities at various historical chlor-alkali plants with mercury contamination and assisted with the development of exhibits for a litigation matter. 

Provided support to an expert witness in a litigation matter involving the chemistry of arsenic and other metals used in historical paint manufacturing. 


For a major oil company, in conjunction with a team of industry and academic scientists, designed and ran a series of laboratory experiments to examine the partitioning of chemical components of weathered oil from sediments to water under various conditions. Duties included the management of the sampling, review of the analytical results, and analysis and reporting of the chemical data.

Managed a project to evaluate the concentrations of chemical components in produced waters from fracking operations over a regional area. Effort included sampling, lab coordination and data validation for a suite of standard organic and inorganic chemicals, including radioisotopes. Additionally, appropriate analytical methods for a list of proprietary chemicals in use in fracking operations were researched and analytical procedures and approaches for future investigations were recommended.

Analyzed chemical and physical data as well as historical documents associated with a gasoline plume in groundwater under an urban area with multiple potential sources. Used various environmental forensic techniques to determine the approximate age of the release and the likely source. Assisted with the preparation of an expert report and worked closely with the client during third party depositions.

Served as chief scientist on an oceanographic survey to collect sediment for chemical and biological analysis to support an NRDA case.

Conducted a site investigation and analyzed samples of groundwater for an environmental forensics case involving a potential leaking underground storage tank for home heating oil. Assisted with expert report preparation.

Reviewed historical and site investigation documents for a natural resources damages case involving historical petroleum refinery operations.


Evaluated proprietary hydraulic oils used in shipboard operations for potential compliance with new regulatory requirements for biodegradability, based on reported chemical properties. Prepared a memo summarizing these results for the client.

Assisted in the production of a technical manual for biotreatment of petroleum based on multiple previously used protocols and other research. Worked closely with the client to develop the document.

Reviewed and summarized available published research on the potential biological transformations of various chlorinated solvents to support an expert witness in a litigation matter.


Provided technical chemistry and microbiology support in a consumer product investigation of corrosive gypsum wallboard with a team that included human health and corrosion scientists. Provided a comprehensive review of potential chemical reactions of wallboard and worked with the team to design experiments to test potential causes of the corrosion.

For a trade organization, researched available literature and wrote a white paper on the analytical methods used to measure chemicals transferred to food associated with the use of mineral oil in food packaging.

Provided technical support in an environmental forensics case of chlorinated solvent groundwater contamination in an urban area. Specific duties included review and summary of historical documents and site investigation results.


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  • Ph.D., Oceanography (Geochemistry), University of California, San Diego, 2005
  • B.S., Environmental Engineering Science, Massachusetts Institute of Technology (MIT), 1999
  • Recipient of the Environmental Protection Agency STAR graduate fellowship