What chemical and microbiological contaminants are present in our drinking water? How did they get in there? How do we keep them out? Who gets exposed to these contaminants, and at what level? What are the human health outcomes of these exposures, if any? And finally, how can we change societal behavior for a healthier and more sustainable future?

These are key questions guiding the day-to-day research activities in my laboratories in the Center for Water and Health at the Johns Hopkins Bloomberg School of Public Health and in the Center for Environmental Biotechnology at Arizona State University's Biodesign Institute.

Finding answers to these questions is exciting but not always easy. An eclectic ensemble of research tools assists us in our inquiry. Water-soluble contaminants are spied upon using liquid chromatography/mass spectrometry (LC/MS); non-polar compounds are tracked by gas chromatography/mass spectrometry (GC/MS). Microbial contaminants can be cultivated, enumerated, and DNA-fingerprinted, or enzymatically digested in order to detect identity-revealing peptides by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS).

Human exposure is evaluated via analysis of contaminants and biomarkers in urine, blood, and breast milk by LC-MS/MS. Proteomic techniques including difference gel electrophoresis (DIGE) can reveal early biological responses in umbilical cord blood serum in response to chemical insults. Links between environmental contamination and adverse human health effects are investigated using database searching and the geographic information system (GIS).

Mass balance calculations help us to keep track of the overall contaminant mass as point sources release their toxic load into rivers and streams, and as contaminants in wastewater treatment plants face the ultimate question: persistence, sorption, volatilization, biotransformation, or mineralization?

Previously and currently funded activities include:

• a community-based translational cancer research project concentrating on human fetal exposure to carcinogens in drinking water;

• a nationwide study on the fate of pharmaceuticals and personal care products (PPCPs) in the environment;

• the JHU National Biosolids Repository funded by a JHU Faculty Research Initiative Award;

• pilot projects concentrating on the development and application of exposure assessment tools for the detection of toxins in water, sediment, biosolids, food, urine, blood and human milk;

• an EPA STAR project concentrating on monitoring techniques for emerging microbial contaminants in drinking water;

• studies on the bioremediation of chemical mixtures funded by the National Institute of Environmental Health Sciences.

As part of the latter project, we are developing novel diagnostic devices (i.e., the In Situ Microcosm Array or ISMA) designed to reveal the best environmental cleanup strategy for a given contaminated site, and to aid in the discovery of microorganisms, biochemical processes and natural products of potential commercial value.

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Drinking water, wastewater, groundwater, water quality, water treatment, bioremediation, biodegradation, biotransformation, bioaccumulation, biosolids, exposure assessment, biomarker, proteomics, mass spectrometry, LC/MS, LC/MS/MS, GC/MS, MALDI-TOF MS, pharmaceuticals, personal care products, pollutants, dioxin, environmental health, MTBE, microbial ecology

2007 Faculty Research Initiative Award, Johns Hopkins Bloomberg School of Public Health

2006 Technical Assessment of Environmental Programs at Los Alamos National Lab, NRC Committee Member, The National Academies

2005 Congress on Emerging Contaminants, RNRF, Washington, DC, Invited Delegate

2005 Faculty Research Initiative Award, Johns Hopkins Bloomberg School of Public Health

2003-05 Maryland State Water Quality Advisory Committee (SWQAC), Member

2003-04 Faculty Senate, Johns Hopkins Bloomberg School of Public Health

2002 Faculty Innovation Award, Johns Hopkins Bloomberg School of Public Health

1996 Vice-President, Environmental Engineering Society, University of Minnesota

1996 Dissertation Fellowship, Outstanding Civil Eng. Student, U of MN

2009 Publications

Heidler J. and R. U. Halden. 2009. Fate of Organohalogens in U.S. Wastewater Treatment Plants and Estimated Chemical Releases to Soils Nationwide from Biosolids Recycling. J. Environ. Monit. (Accepted for Publication).

Higgins, C. P., Z. J. Paesani, T. E. A. Chalew, and R. U. Halden. 2009. Bioaccumulation of Triclocarban in Lumbriculus variegates. Environ. Toxicol. Chem. (In Press).

Von Seggern, C., and R. U. Halden.*  2009. Detection of bioterrorism agents and related public health threats utilising matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS). Int. J. Health Sci. 2(2):197-203.

Halden, R. U. 2009. Book Review: “Pharma-Ecology – The Occurrence and Fate of Pharmaceuticals and Personal Care Products in the Environment” by Patrick K. Jjimba. Environ. Health Perspect. 117(4):A172.

Zhang, Y., N. Jiao, D. R. Colquhoun, R. U. Halden, and F. Cheng. 2009. Protein Modifications Relate to Phage Resistance in a Marine Roseobacter. Aquatic Microbial Ecology. 55(2):203-207.

Chalew, T. and R. U. Halden.*  2009. Environmental Exposure of Aquatic and Terrestrial Biota to Triclosan and Triclocarban. J. Am. Water Res. Assoc. 45(1):3-13.

Colquhoun, D. R., L. R. Goldman, R. N. Cole, M. Gucek, M. Mansharamani, F. R. Witter, B. J. Apelberg, and R. U. Halden.* 2009. Global Screening of Human Cord Blood Proteomes for Biomarkers of Toxic Exposure. Environmental Health Perspectives 117(5):832-838. [Online]

2008 Publications

Colquhoun, D. R., L. R. Goldman, R. N. Cole, M. Gucek, M. Mansharamani, F. R. Witter, B. J. Apelberg, and R. U. Halden RU. 2008. Global Screening of Human Cord Blood Proteomes for Biomarkers of Toxic Exposure and Effect. In Press at: Environ. Health. Perspect. doi:10.1289/ehp.11816. [Published Online 2 December 2008]

Halden, R. U. 2008. PCPs persist for decades. TRAC-TRENDS IN ANALYTICAL CHEMISTRY 27(6) 6.

Heidler, J. and R. U. Halden. 2008. Meta-analysis of Mass Balances for Monitoring Chemical Fate during Wastewater Treatment. Environ. Sci. Technol. Published July 22 online ahead of print. HTML or PDF.

Rittmann, B. E., R. Krajmalnik-Brown, and R. U. Halden. 2008. Pre-genomic, genomic and post-genomic study of microbial communities involved in bioenergy. Nature Reviews Microbiology. [Jul 7, Epub ahead of print] PMID: 18604223.

Apelberg B. J., Goldman L. R., Halden, R. U., Witter, F. R., Herbstman, J. B., and Needham, L. L. 2008. Perfluoroalkane acids: Apelberg et al. respond. Environ. Health Perspect. 116(6):A238-9.

Herbstman, J. B., A. Sjödin, B. J. Apelberg, F. R. Witter, R. U. Halden, D. G. Patterson, Jr., S. R. Panny, L. L. Needham and L. R. Goldman. 2008. Birth Delivery Mode Modifies the Associations between Prenatal PCB and PBDE and Neonatal Thyroid Hormone Levels. Environ. Health Perspect. EHP-in-Press. doi:10.1289/ehp.11379.

Miller, T. R., J. Heidler, S. N. Chillrud, A. DeLaquil, J. C. Ritchie, J. N. Mihalic, R. Bopp, and R. U. Halden. 2008. Fate of Triclosan and Evidence for Reductive Dechlorination of Triclocarban in Estuarine Sediment. Environ. Sci. Technol. 42:4570-4576. HTML.

Young, T.A., J. Heidler, C. R. Matos-Pérez, A. Sapkota, T. Toler, K. E. Gibson, K. J. Schwab and R. U. Halden. 2008. Ab Initio and In Situ Comparison of Organic Wastewater Compounds as Indicators of Sewage-derived Microbes in Surface Waters. Environ. Sci. Technol. 42(9); 3335-3340.

Kim, S. R., R. U. Halden, and T. J. Buckley. 2008. Polycyclic Aromatic Hydrocarbons in Human Milk of Nonsmoking U.S. Women. Environ. Sci. Technol. 42(7); 2663-2667.

2007 Publications

Herbstman J. B., Sjödin A., Apelberg B. J., Witter F. R., Patterson D. G., Halden, R. U., Jones, R. S., Park, A., Zhang, Y., Heidler, J., Needham, L. L., and Goldman, L. R. 2007. Determinants of Prenatal Exposure to Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in an Urban Population. Environ. Health Perspect. 115(12):1794-800.; Study Information.

Apelberg, B. J., F. R. Witter, J. B. Herbstman, A. M. Calafat, R. U. Halden, L. L. Needham, and L. R. Goldman. 2007. Cord Serum Concentrations of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Relation to Weight and Size at Birth. Environ. Health Perspect. 115(11):1670-1676.; Study Information.

Halden, R. U. (Contributing Author). 2007. Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory—Final Report—Committee for the Technical Assessment of Environmental Programs at the Los Alamos National Laboratory. ISBN-10: 0-309-10619-2. 104 Pages. Nuclear and Radiation Studies Board, Division of Earth and Life Studies. National Research Council of The National Academies, The National Academies Press, Washington, D.C.

Apelberg, B. J., Goldman, L. R., Calafat, A. M., Herbstman, J. B., Kuklenyik, Z., Heidler, J., Needham, L. N., Halden, R. U., and F. R. Witter. 2007. Determinants of Fetal Exposure to Polyfluoroalkyl Compounds in Baltimore, Maryland. Environ. Sci. Technol. 41(11): 3891-3897.; Study Information.

Kim, S. R., Halden, R. U., and T. J. Buckley. 2007. Volatile Organic Compounds in Human Milk: Methods and Measurements. Environ. Sci. Technol. 41(5):1662-1667

Miller, T. R., M. P. Franklin, and R. U. Halden. 2007. Bacterial Community Analysis of Shallow Groundwater Undergoing Sequential Anaerobic and Aerobic Chloroethene Biotransformation. FEMS Microbiol. Ecol. 60(2):299-311..

Heidler, J., and R. U. Halden. 2007. Mass Balance Assessment of Triclosan Removal During Conventional Sewage Treatment. Chemosphere 66(2):362-369.

Sapkota, A., J. Heidler, and R. U. Halden. 2007. Detection of Triclocarban and Two Co-Contaminating Chlorocarbanilides in U.S. Aquatic Environments Using Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry. Environ. Res. 103(1):21-29.

2006 Publications

Halden, R. U. (Contributing Author). Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory—Interim Status Report—Committee for the Technical Assessment of Environmental Programs at the Los Alamos National Laboratory, Nuclear and Radiation Studies Board, Division of Earth and Life Studies. 34 Pages. ISBN-10: 0-309-10391-6. National Research Council of The National Academies, The National Academies Press, Washington, D.C., 2006.

Heidler, J., A. Sapkota, and R. U. Halden. 2006. Partitioning, Persistence, and Accumulation in Digested Sludge of the Topical Antiseptic Triclocarban During Wastewater Treatment. Environ. Sci. Technol. 40(11):3634-3639. ES&T A-Pages 40(11):3444-3445. Chem & Eng News Online.

Halden, R. U. 2006. Comment on “Accumulation of Contaminants in Fish from Wastewater Treatment Wetlands.” Environ. Sci. Technol. 40(10):3437. USGS Response to the Comment: 40(10):3438-3439.

Herbstman, J; Sjödin, A; Apelberg, B; Witter, F; Patterson, D; Halden, R; Jones, R; Park, A; Zhang, Y; Heidler, J; Needham, L; Goldman, L. 2006. Determinants of Prenatal Exposure to Polybrominated Diphenyl Ethers (PBDEs) in an Urban Population. Epidemiology 17 (6): S403-S403.

Halden, R.U. 2006. Comment on “Biological Removal of Polychlorinated Dibenzo-p-dioxins from Incinerator Fly Ash by Sphingomonas wittichii RW1” by I.-H. Nam, Y.-M. Kim, B.-H. Kim, K. Murugesan, and Y.-S. Chang. Water Research 40(9):1918-1920. Response to Comment, 40(11):2246-2247.

Colquhoun, D. R., Schwab, K. J., Cole, R. N., and R. U. Halden. 2006. Detection of Norovirus Capsid Protein in Authentic Standards and in Stool Extract by Matrix-Assisted Laser Desorption Ionization and Nanospray Mass Spectrometry. Appl. Environ. Microbiol. 72(4):2749-2755.

Sapkota, A., R. U. Halden, F. Dominici, J. P. Groopman, and T. J. Buckley. 2006. Urinary Biomarkers of 1,3-Butadiene in Environmental Settings Using Liquid Chromatography Isotope Dilution Tandem Mass Spectrometry. Chem. Biol. Interact. 160(1):70-79.

Apelberg B., Calafat A., Herbstman J., Witter F., Halden R., Kuklenyik Z., Heidler J., Needham L., Goldman L. Magnitude and determinants of perfluorinated chemical levels in cord blood. Epidemiology 17 (6): S394-S394.

Dong, W., G. Xie., T. R. Miller, M. P. Franklin, T. Palmateer Oxenberg, E. J. Bouwer, W. P. Ball, and R. U. Halden. 2006. Sorption and Bioreduction of Hexavalent Uranium at a Military Facility by the Chesapeake Bay. Environ. Pollut. 142:132-142.

2005 Publications

Naples, J. M., C. Shiff, and R. U. Halden. 2005. Reduction of Infectivity of Schistosome Cercariae by Application of Cercariacidal Oil to Water. Am. J. Trop. Med. Hyg. 73(5):956-961. Science Mag.

Halden, R. U., D. R. Colquhoun, and E. S. Wisniewski. 2005. Identification and Phenotypic Characterization of Sphingomonas wittichii Strain RW1 by Peptide Mass Fingerprinting using Matrix-Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry. Appl. Environ. Microbiol. 71(5):2442-2451.

Halden, R. U. 2005. Methods and systems for sampling, screening and diagnosis. PCT International Patent Application No. WO 2005/076887.

Halden, R. U. and D. H. Paull. 2005. Co-occurrence of triclocarban and triclosan in U.S. water resources. Environ. Sci. Technol. 39(6):1420-1426.

Halden, R. U., and D. H. Paull. 2005. Response to Comment On "Co-Occurrence of Triclocarban and Triclosan in U.S. Water Resources." Environ. Sci. Technol. Published On-line on July 6, 2005. in Response to Comment Published On-line on July 20, 2005.

2004 Publications

Halden, R. U. and D. H. Paull. 2004. Analysis of triclocarban in aquatic samples by liquid chromatography electrospray ionization mass spectrometry. Environ. Sci. Technol. 38(18):4849-4855.

Halden, R. U. 2004. Method and apparatus for environmental monitoring and bioprospecting. PCT International Patent Application No. WO 2004/081530.

Heidler, J., and R. U. Halden. 2004. Fate of antimicrobial compounds during wastewater treatment. Presented at: Environmental Aspects of Pharmaceuticals and Personal Care Products. Session II. Cosponsored by the U.S. EPA. Division of Environmental Chemistry. 228th American Chemical Society Meeting, Philadelphia, PA. Wednesday, August 25.

2003 Publications

Vancheeswaran, S., S. Yu, P. Daley, R. U. Halden, K. J. Williamson, J. D. Ingle Jr., and L. Semprini. 2003. Intrinsic remediation of trichloroethene driven be tetraalkoxysilanes as co-contaminants: results from microcosm and field studies. Remediation 13(2):7-25.

2002 Publications

Lowe, M., E. L. Madsen, K. Schindler, C. Smith, S. Emrich, F. T. Robb, and R. U. Halden. 2002. Geochemistry and Microbial Diversity of a Trichloroethene-Contaminated Superfund Site Undergoing In Situ Reductive Dechlorination. FEMS Microbiol. Ecol. 40(2):123-134.

2001 Publications

Kane, S. R., H. R. Beller, T. C. Legler, C. J. Koester, R. U. Halden, and A. M. Happel. 2001. Aerobic Metabolism of Methyl tert-Butyl Ether by Aquifer Bacteria. Appl. Environ. Microbiol. 67(12):5824-5829.

Halden, R. U., A. M. Happel, and S. R. Schoen. 2001. Evaluation of Standard Methods for the Analysis of Methyl tert-Butyl Ether and Related Oxygenates in Gasoline-Contaminated Groundwater. Environ. Sci. Technol., 35(7):1469-1474 and 1560.

2000 Publications

Koester, C. J., H. R. Beller, and R. U. Halden. 2000. Analysis of Perchlorate in Groundwater by Electrospray Ionization Mass Spectrometry/Mass Spectrometry. Environ. Sci. Technol., 34(9):1862-1864.

Halden, R. U., B. G. Halden, and D. F. Dwyer. 2000. Transformation of Mono- and Dichlorinated Phenoxybenzoates by Phenoxybenzoate-dioxygenase in Pseudomonas pseudoalcaligenes Strain POB310 and a Modified, Diarylether-Mineralizing Bacterium. Biotechnol. Bioeng., 69(1):107-112.

1999 Publications

Halden, R. U., S. M. Tepp, B. G. Halden, and D. F. Dwyer. 1999. Degradation of 3-Phenoxybenzoic Acid in Soil by Pseudomonas pseudoalcaligenes Strain POB310(pPOB) and Two Modified Pseudomonas Strains. Appl. Environ. Microbiol., 65(8):3354-3359.

Halden, R. U., B. G. Halden, and D. F. Dwyer. 1999. Removal of Dibenzofuran, Dibenzo-p-Dioxin, and 2-Chlorodibenzo-p-Dioxin from Soils Inoculated with Sphingomonas sp. Strain RW1. Appl. Environ. Microbiol., 65(5):2246-2249.

Vancheeswaran, S., R. U. Halden, K. J. Williamson, J. D. Ingle Jr., and L. Semprini. 1999. Abiotic and Biological Transformation of Tetraalkoxysilanes and TCE, c-DCE Cometabolism Driven by Tetrabutoxysilane-Degrading Microorganisms. Environ. Sci. Technol., 33(7):1077-1085.