Michelle L Hladik, PhD
(She/her)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 is focused on pesticides but also includes other organic contaminants. I direct a research laboratory that is focused on developing new methods to measure pesticides and their degradates in water, sediment, and biota. My laboratory specializes in small samples sizes, complex matrices, and non-standard procedues. 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.
Professional Experience
Research Chemist, USGS, California Water Science Center, Sacramento, 2006 to present
Chemist, USGS, California Water Science Center, Sacramento, 2005-2006
Graduate Fellow/Research and Teaching Assistant, Deparment of Geography and Environmental Engineering, Johns Hopkins University, 1999-2005
Undergraduate Research Summer Institute, Department of Chemistry, Vassar College, 1997,1998
Undergraduate Research and Teaching Assistant, Department of Chemistry, Vassar College ,1997,1998
Education and Certifications
Ph.D. 2005, Environmental Engineering and Chemistry, Johns Hopkins University, Baltimore, Maryland
B.A. 1999, Chemistry, Vassar College, Poughkeepsie, New York
Science and Products
Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities
A critical review on the potential impacts of neonicotinoid insecticide use: Current knowledge of environmental fate, toxicity, and implications for human health
Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption
Mixed organic and inorganic tapwater exposures and potential effects in greater Chicago area, USA
Uptake, metabolism, and elimination of fungicides from coated wheat seeds in Japanese quail (Coturnix japonica)
Exposure and potential effects of pesticides and pharmaceuticals in protected streams of the US National Park Service southeast Region
Pesticide mixtures in the Sacramento–San Joaquin Delta, 2016–17: Results from year 2 of the Delta Regional Monitoring Program
Review of and recommendations for monitoring contaminants and their effects in the San Francisco Bay−Delta
Effects of the neonicotinoid insecticide clothianidin on southern leopard frog (Rana sphenocephala) tadpole behavior
Urban stormwater: An overlooked pathway of extensive mixed contaminants to surface and groundwaters in the United States
Toxicokinetics of imidacloprid-coated wheat seeds in Japanese quail (Coturnix japonica) and an evaluation of hazard
Chlorinated byproducts of neonicotinoids and their metabolites: An unrecognized human exposure potential?
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Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities
Streambed sediment is commonly analyzed to assess occurrence of hydrophobic pesticides and risks to aquatic communities. However, stream biofilms also have the potential to accumulate pesticides and may be consumed by aquatic organisms. To better characterize risks to aquatic life, the U.S. Geological Survey Regional Stream Quality Assessment measured 93 current-use and 3 legacy pesticides in bedAuthorsBarbara Mahler, Travis S. Schmidt, Lisa H. Nowell, Sharon L. Qi, Peter C. Van Metre, Michelle Hladik, Daren M. Carlisle, Mark D. Munn, Jason MayA critical review on the potential impacts of neonicotinoid insecticide use: Current knowledge of environmental fate, toxicity, and implications for human health
Neonicotinoid insecticides are widely used in both urban and agricultural settings around the world. Historically, neonicotinoid insecticides have been viewed as ideal replacements for more toxic compounds, like organophosphates, due in part to their perceived limited potential to affect the environment and human health. This critical review investigates the environmental fate and toxicity of neonAuthorsHans-Joachim Lehmler, Dana W. Kolpin, Michelle L. Hladik, John D. Vargo, Keith E. Schilling, Gregory H. LeFevre, Tonya L. Peeples, Matthew C. Poch, Lauren E. LaDuca, David M. Cwiertny, R. William FieldUptake and toxicity of clothianidin to monarch butterflies from milkweed consumption
Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need additional data to help estimate risk for wild monarch butterflies exposed to those inAuthorsTimothy A. Bargar, Michelle L. Hladik, Jaret C. DanielsMixed organic and inorganic tapwater exposures and potential effects in greater Chicago area, USA
Safe drinking water at the point of use (tapwater, TW) is a public-health priority. TW exposures and potential human-health concerns of 540 organics and 35 inorganics were assessed in 45 Chicago area United States (US) homes in 2017. No US Environmental Protection Agency (EPA) enforceable Maximum Contaminant Level(s) (MCL) were exceeded in any residential or water treatment plant (WTP) pre-distribAuthorsPaul Bradley, Maria Argos, Dana W. Kolpin, Shannon M. Meppelink, Kristin M. Romanok, Kelly L. Smalling, Michael J. Focazio, Joshua M. Allen, Julie E. Dietze, Michael J. Devito, Ariel Donovan, Nicola Evans, Carrie E. Givens, James L. Gray, Christopher P. Higgins, Michelle Hladik, Luke Iwanowicz, Celeste A. Journey, Rachael F. Lane, Zachary Laughrey, Keith A. Loftin, R. Blaine McCleskey, Carrie A. McDonough, Elizabeth K Medlock Kakaley, Michael T. Meyer, Andrea Holthouse-Putz, Susan D Richardson, Alan Stark, Christopher P. Weis, Vickie S. Wilson, Abderrahman ZehraouiUptake, metabolism, and elimination of fungicides from coated wheat seeds in Japanese quail (Coturnix japonica)
Pesticides coated to the seed surface potentially pose an ecological risk to granivorous birds that consume incompletely buried or spilled seeds. To assess the toxicokinetics of seeds treated with current-use fungicides, Japanese quail (Coturnix japonica) were orally dosed with commercially coated wheat seeds. Quail were exposed to metalaxyl, tebuconazole, and fludioxonil at either a low (0.07, 0.AuthorsMichael S. Gross, Thomas G. Bean, Michelle Hladik, Barnett A. Rattner, Kathryn KuivilaExposure and potential effects of pesticides and pharmaceuticals in protected streams of the US National Park Service southeast Region
Globally protected areas offer refugia for a broad range of taxa including threatened and endangered species. The United States National Park Service (NPS) manages public lands to preserve biodiversity, but increasing park visitation and development of surrounding landscapes increase exposure to and effects from bioactive contaminants. The risk (exposure and hazard) to NPS protected-stream ecosystAuthorsPaul M. Bradley, Kristin M. Romanok, Jeffrey R. Duncan, William Battaglin, Jimmy Clark, Michelle Hladik, Bradley Huffman, Luke Iwanowicz, Celeste A. Journey, Kelly SmallingByEcosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, California Water Science Center, Colorado Water Science Center, Eastern Ecological Science Center, New Jersey Water Science Center, South Atlantic Water Science Center (SAWSC)Pesticide mixtures in the Sacramento–San Joaquin Delta, 2016–17: Results from year 2 of the Delta Regional Monitoring Program
The Delta Regional Monitoring Program was developed by the Central Valley Regional Water Quality Control Board in response to the decline of pelagic fish species in the Sacramento–San Joaquin Delta that was observed in the early 2000s. The U.S. Geological Survey, in cooperation with the Delta Regional Monitoring Program, has been responsible for collecting and analyzing surface-water samples for aAuthorsMatthew D. De Parsia, Emily E. Woodward, James L. Orlando, Michelle L. HladikReview of and recommendations for monitoring contaminants and their effects in the San Francisco Bay−Delta
Legacy and current-use contaminants enter into and accumulate throughout the San Francisco Bay−Delta (Bay−Delta), and are present at concentrations with known effects on species important to this diverse watershed. There remains major uncertainty and a lack of focused research able to address and provide understanding of effects across multiple biological scales, despite previous and ongoing emphaAuthorsRichard E Connon, Simone Hasenbein, Susanne M. Brander, Helen C. Poynton, Erika B Holland, Daniel Schlenk, James Orlando, Michelle Hladik, Tracy K. Collier, Nathaniel L Scholz, John P Incardona, Nancy D. Denslow, Amro Hamdoun, Sascha Nicklisch, Natalia Garcia-Reyero, Edward J. Perkins, Evan P Gallagher, Xin Deng, Dan Wang, Stephanie Fong, Richard S Breuer, Mehrdad Hajibabei, James B Brown, John K Colbourne, Thomas M Young, Gary Cherr, Andrew Whitehead, Anne E. TodghamEffects of the neonicotinoid insecticide clothianidin on southern leopard frog (Rana sphenocephala) tadpole behavior
Neonicotinoid insecticides are highly water soluble with relatively long half-lives, which allows them to move into and persist in aquatic ecosystems. However, little is known of the impacts of neonicotinoids on non-target vertebrates, especially at sublethal concentrations. We evaluated the effects of the neonicotinoid clothianidin on the behavior of southern leopard frog tadpoles (Rana sphenocepAuthorsJ. N. Holtswarth, F. E. Rowland, Holly J. Puglis, Michelle Hladik, Elisabeth B. WebbUrban stormwater: An overlooked pathway of extensive mixed contaminants to surface and groundwaters in the United States
Increasing global reliance on stormwater control measures to reduce discharge to surface water, increase groundwater recharge, and minimize contaminant delivery to receiving waterbodies necessitates improved understanding of stormwater-contaminant profiles. A multi-agency study of organic and inorganic chemicals in urban stormwater from 50 runoff events at 21 sites across the United States demonstAuthorsJason R. Masoner, Dana W. Kolpin, Isabelle M. Cozzarelli, Larry B. Barber, D.S. Burden, William T. Foreman, Kenneth J. Forshay, Edward Furlong, Justin F. Groves, Michelle Hladik, Matthew E. Hopton, Jeanne B. Jaeschke, Steffanie H. Keefe, David Krabbenhoft, Richard Lowrance, Kristin Romanok, David L. Rus, William R. Selbig, Brad Williams, Paul BradleyByWater Resources Mission Area, Science Synthesis, Analysis and Research Program, Contaminant Biology, Science Analytics and Synthesis (SAS) Program, Toxic Substances Hydrology, California Water Science Center, Central Midwest Water Science Center, New Jersey Water Science Center, Oklahoma-Texas Water Science Center, South Atlantic Water Science Center (SAWSC), Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center, Reston Biogeochemical Processes in Groundwater LaboratoryToxicokinetics of imidacloprid-coated wheat seeds in Japanese quail (Coturnix japonica) and an evaluation of hazard
Birds are potentially exposed to neonicotinoid insecticides by ingestion of coated seeds during crop planting. Adult male Japanese quail were orally dosed with wheat seeds coated with an imidacloprid (IMI) formulation at either 0.9 mg/kg body weight (BW) or 2.7 mg/kg BW (~3 and 9% of IMI LD50 for Japanese quail, respectively) for 1 or 10 days. Quail were euthanized between 1 and 24 h post-exposureAuthorsThomas G. Bean, Michael S. Gross, Natalie K. Karouna-Renier, Paula F. P. Henry, Sandra L. Schultz, Michelle Hladik, Kathryn Kuivila, Barnett A. RattnerChlorinated byproducts of neonicotinoids and their metabolites: An unrecognized human exposure potential?
We recently reported the initial discovery of neonicotinoid pesticides in drinking water and their potential for transformation through chlorination and alkaline hydrolysis during water treatment. The objectives of this research were: (1) to determine if neonicotinoid metabolites are relevant to drinking water exposure and (2) to identify the products formed from chlorination of neonicotinoids andAuthorsKathryn L. Klarich Wong, Danielle T. Webb, Matthew R. Nagorzanski, Dana W. Kolpin, Michelle L. Hladik, David M. Cwiertny, Gregory H. LeFevre - News