Michelle L Hladik

I am an environmental organic chemist whose current research focuses on the fate and transport of current-use pesticides and other organic contaminants in aquatic and terrestrial environments.


Much of my research has focused on pesticides but has expanded to include other organic contaminants. I oversee a research laboratory that is focused on developing new methods to measure pesticides and their degradates in water, sediment and biota. Additionally, I also work on developing methods and measuring disinfection by-products in treated water (especially those that are not-currently regulated and are understudied) with a focus on wastewater discharges. 

I have a B.A. in Chemistry from Vassar College (1999) and a Ph.D. in Environmental Engineering from Johns Hopkins University (2005).


Hubbard, L.E., Kolpin, D.W., Fields, C., Hladik, M.L. and Iwanowicz, L.R., 2017, Response to the 2015 avian influenza outbreak in the Midwestern United States: study design, lessons learned, and select results, Environ. Res., v. 158, pp. 212-224.

Klarich, K.L., Pflug, N.C., DeWald, E.M., Hladik, M.L., Kolpin, D.W., Cwiertny, D.M. and LeFevre, G.H., 2017, Occurrence of neonicotinoid insecticides in finished drinking water and persistence during drinking water treatment, Environ. Sci. Technol. Lett., v. 4, pp. 168-173.

Bradley, P.M., Journey, C.A., Romanok, K.M., Barber, L.B., Buxton, H.T., Foreman, W.T., Furlong, E.T., Glassmeyer, S.T., Hladik, M.L., Iwanowicz, L.R., Jones, D.K., Kolpin, D.W., Kuivila, K.M., Loftin, K.A., Mills, M.A., Meyer, M.T., Orlando, J.L., Reilly, T.J., Smalling, K.L. and Villeneuve, D.L., 2017, Expanded target-chemical analysis reveals extensive mixed-organic-contaminant exposure in USA streams, Environ. Sci. Technol., v. 51, pp 4792-4802.

Romanok, K.M., Reilly, T.J., Barber, L.B., Buxton, H.T., Foreman, W.T., Furlong, E.T., Glassmeyer, S.T., Hladik, M.L., Iwanowicz, L.R., Jones, D.K., Journey, C.A., Kolpin, D.W., Kuivila, K.M., Loftin, K.A., Mills, M.A., Meyer, M.T., Orlando, J.L., Smalling, K.L., Villeneuve, D.L. and Bradley, P.M., 2017, Methods used to characterize the chemical composition and biological activity of environmental waters throughout the United States, 2012–14. U.S. Geological Survey Open File Report 2017-1011, 115p. 

Hladik, M.L., Bradbury, S., Schulte, L.A., Helmers, M., Witte, C., Kolpin, D.W., Garrett, J.D. and Harris, M., 2017, Neonicotinoid insecticide removal by prairie strips in row-cropped watersheds with historical seed coating use, Agric. Ecosyst. Environ., v. 241, pp. 160-167.

Orem, W., Varonka, M., Crosby, L., Haase, K., Loftin, K., Hladik, M., Akob, D.M., Tatu, C., Mumford, A., Jaeschke, J., Bates, A., Schell, T. and Cozzarelli, I., 2017, Organic geochemistry and toxicology of a stream impacted by unconventional oil and gas wastewater disposal operations, Appl. Geochem., v. 80, pp. 155-167.

Goff, A.D., Saranjampour, P., Ryan, L.M., Hladik, M.L., Covi, J.A., Armbrust, K.L. and Brander, S.M., 2017, The effects of fipronil and the photodegradation product fipronil desulfinyl on growth and gene expression in juvenile blue crabs, Callinectes sapidus, at different salinities, Aquat. Toxicol., v. 186, pp. 96-104.

Woodward, E.E., Hladik, M.L., Kolpin, D.W., 2016, Nitrapyrin in streams: The first study documenting off-field transport of a nitrogen stabilizer compound, Environ. Sci. Techol. Lett., v. 3, pp. 387-392.

Rogers, H.A., Schmidt, T.S., Dabney, B.L., Hladik, M.L., Mahler, B.J., Van Meter, P.C., 2016, Bifenthrin causes trophic cascades in aquatic food webs and alters subsidies to terrestrial food webs, Environ. Sci. Technol., v. 50, pp. 11974-11983.

Forister, M., Cousens, B., Harrison, J., Casner, K., Thorne, J., Waetjen, D., Nice, C., De Parsia, M., Hladik, M., Meese, R., van Vliet, H., Shaprio, A., 2016, Increasing neonicotinoid use and the declining butterfly fauna of lowland California, Biol. Lett., v. 12(8), 20160475

Carpenter, K.D., Kuivila, K.M., Hladik, M.L., Haluska, T., Cole, M.B., 2016, Storm-event-transport of urban-use pesticides to streams likely impairs invertebrate assemblages, Environ. Monit. Assess., v. 188, article 345.

Hladik, M.L., Hubbard, L.E., Kolpin, D.W., and Focazio, M.L., 2016, Dairy-impacted wastewater is a source of iodinated disinfection byproducts in the environment, Environ. Sci. Technol. Lett., v. 3, pp. 190-193.

Elskus, A.A., Smalling, K.L., Hladik, M.L., Kuivila, K.M., 2016, Effects of two fungicide formulations on microbial and macroinvertebrate leaf decomposition under laboratory conditions, Environ. Toxciol. Chem., v. 35, pp, 2834-2844.

Hladik, M.L., Vandever, M., and Smalling K.L., 2016, Expsoure of native bees foraging in an agricultural landscape to current-use pesticides, Sci. Tot. Environ., v. 542, pp. 469-477.

Hladik, M.L. and Kolpin, D.W., 2016, First national-scale reconnaissance of neonicotinoid insecticides in streams across the U.S.A., Environ. Chem., v. 13, pp. 12-20.

Smalling, K.L., Reeves, R., Muths, E., Vandever, M., Battaglin, W.A., Hladik, M.L. and Pierce, C., 2015, Pesticide concentrations in frog tissue and wetland habitats in a landscape dominated by agriculture, Sci. Tot. Environ., v. 502, pp. 80-90.

Barber, L.B., Hladik, M.L., Vajda, A.M., Fitzgerald, K.C., Douville, C., 2015, Impact of wastewater infrastructure upgrades on the urban water cycle: reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection, Sci. Total. Environ., v. 529, pp. 264-274

Hladik, M.L., Focazio, M.J. and Engle, M., 2014, Discharges of produced waters from oil and gas extraction via wastewater treatment plants are sources of disinfection by-products to receiving streams, Sci. Tot. Environ., v. 466-467, pp. 1085-1093.

Hladik, M.L., Kolpin, D.W., and Kuivila, K.M., 2014, Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA, Environ. Poll., v. 193, pp. 189-196.

Romanok, K.M., Reilly, T.J., Lopez, A.R., Trainor, J.J., Hladik, M.L., Stanley, J.K., and Farrar, D., 2014, Characterization of selected bed-sediment-bound organic and inorganic contaminants and toxicity, Barnegat Bay and major tributaries, New Jersey, 2012: U.S. Geological Survey Data Series 867, 51 p. [Link]

Orlando, J., McWayne, M., Sanders, C. and Hladik, M., 2014, Dissolved Pesticide Concentrations Entering the Sacramento–San Joaquin Delta from the Sacramento and San Joaquin Rivers, California, 2012–13: U.S. Geological Survey Data Series 876, 28 p. [Link]

Orlando, J.L., McWayne, M., Sanders, C., and Hladik, M., 2013, Dissolved pesticide concentrations in the Sacramento-San Joaquin Delta and Grizzly Bay, California, 2011–12: U.S. Geological Survey Data Series 779, 24 p. [Link]

Reilly, T.J., Smalling, K.L., Meyer, M.T., Sandstrom, M.W., Hladik M.L., Boehlke, A., Fishman, N.S., Battaglin, W.A., and Kuivila, K.M., 2013, Occurrence of pesticides in groundwater and sediment and mineralogy of sediments and grain coatings underlying the Rutgers Agricultural Research and Extension Center, Upper Deerfield, New Jersey, 2007: U.S. Geological Survey Data Series 811, 53 p. [Link]

Kuivila, K.M., Hladik, M.L., Ingersoll, C.G., Kemble, N.E., Moran, P.W., Calhoun, D.L., Nowell, L.H. Gilliom, R.J., 2012, Occurrence and potential sources of pyrethroid insecticides in stream sediments from seven U.S. metropolitan areas. Environ. Sci. Technol. v. 46, pp. 4297-4303.

Hladik, M.L. and Kuivila, K.M., 2012, Pyrethroid insecticides in bed sediments from urban and agricultural streams across the United States, J. Environ. Monit. v. 14, pp. 1838-1845.

Brander, S.M., Mosser, C.M., Geist, J., Hladik, M.L. and Werner, I., 2012, Esfenvalerate toxicity to the cladoceran Ceriodaphnia dubia in the presence of green algae, Pseudokirchneriella subcapitata,Ecotoxicology v. 21, pp. 2409-2418.

Hladik, M.L. and Calhoun, D.L., 2012, Analysis of the herbicide diuron, three diuron degradates, and six Neonicotinoid insecticides in water – method and application, USGS Scientific Investigations Report 2012-5206, 10 p. [Link]

Hladik, M.L. and McWayne, M.M., 2012, Methods of analysis—determination of pesticides in sediment using gas chromatography/mass spectrometry, USGS Techniques and Methods Report 5-C3, 18 p.[Link]

Moran, P.W., Calhoun, D.L., Nowell, L.H., Kemble, N.E., Ingersoll, C.G., Hladik, M.L., Kuivila, K.M., Falcone, J.A., and Gilliom, R.J., 2012, Contaminants in stream sediments from seven U.S. metropolitan areas--Data summary of a national pilot study: U.S. Geological Survey Scientific Investigations Report 2011-5092, 66 p. [Link]

Domagalski, J.L., Weston, D.P., Zhang, M.H. and Hladik, M.L., 2010, Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA, Environ. Toxicol. Chem., v. 29, pp. 813-823.

Hladik, M.L., Orlando, J.L. and Kuivila, K.M., 2009, Collection of Pyrethroids in Water and Sediment Matrices: Development and Validation of a Standard Operating Procedure, USGS Scientific Investigations Report 2009-5012, 22 p. [Link]

Hladik, M.L., Smalling, K.L. and Kuivila, K.M., 2009, Methods of Analysis—Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry, USGS Techniques and Methods Report 5-C2, 18 p. [Link]

Hladik, M.L. and Kuivila, K.M., 2009, Assessing the occurrence and distribution of pyrethroids in water and suspended sediments, J. Agric. Food Chem., v. 57, pp. 9079-9085.

Hladik, M.L., Domagalski, J.L., Kuivila, K.M., 2009, Concentrations and loads of suspended sediment-associated pesticides in the San Joaquin River, California and tributaries during storm events, Sci. Tot. Enviorn., v. 408, pp. 356-364.

Hladik, M.L. and Orlando, J.L., 2008, Level 1 water-quality inventory of baseline levels of pesticides in urban creeks: Golden Gate National Recreation Area and Presidio of San Francisco, USGS Data Series 338, 14p. [Link]

Hladik, M.L. and Kuivila., K.M., 2008, Analysis of chlorothalonil and three degradates in sediment and soil, J. Agric. Food Chem., v. 56 (7), pp. 2310-2314.

Hladik, M.L., Smalling, K.L., and Kuivila, K.M., 2008, A multi-residue method for the analysis of pesticides and pesticide degradates in water using HLB solid-phase extraction and gas chromatography-ion trap mass spectrometry, Bull. Environ. Contam. Toxicol. v. 80, pp.139-144.

Hladik, M. L., Bouwer, E.J., and Roberts, A.L., 2008, Neutral chloroacetamide herbicide degradates and related compounds in Midwestern United States drinking water sources, Sci. Total. Environ., v. 390,pp. 155-165.

Hladik, M.L., Bouwer, E.J., and Roberts, A.L., 2008, Neutral degradates of chloroacetamide herbicides: occurrence in drinking water and removal during conventional water treatment, Wat. Res., v. 42, pp. 4905-4914.

Kuivila, K.M. and Hladik, M.L., 2008, Understanding the occurrence and transport of current-use pesticide in the San Francisco Estuary Watershed, San Francisco Estuary and Watershed Science, v. 6 (3), article 2.

Hladik, M.L. and K.M. Kuivila., 2008, Occurrence of pyrethroids in bed and suspended sediments in California. In Synthetic Pyrethroids: Occurrence and Behavior in Aquatic Environments, J. Gan, F. Spurlock, P. Hendley, D. Weston, Eds; ACS Symposium Series No. 991; American Chemical Society: Washington, DC; pp. 55-71.

Hladik, M. L., Roberts A.L. and Bouwer, E.J., 2006, Chloroacetamide herbicides and their transformation products in drinking water. Report 91123; AWWA Research Foundation, Denver, CO, 108 pp.

Hladik, M.L., Bouwer, E.J., and Roberts, A.L., 2005, Removal of neutral chloroacetamide herbicide degradates during simulated unit processes for drinking water treatment, Water Res., v. 39pp. 5033-5044.

Hladik, M.L., Hsiao, J.J., and Roberts, A.L., 2005, Are neutral chloroacetamide herbicide degradates of potential environmental concern? Analysis and occurrence in the upper Chesapeake Bay, Environ. Sci. Technol., v. 39, pp. 6561-6574.