Michael Gross is a Research Chemist at the California Water Science Center.
My research focuses the analysis of multiclass, current-use pesticides and their metabolites in tissues (brain, kidney, liver, and muscle), plasma, and excrement. I conduct method development and validation for the extraction, clean-up, and analysis of organic contaminants in complex matrices. Ongoing studies investigate the toxicokinetics of pesticide treated seeds in model bird species following a laboratory exposure and determine the fate of pesticides and their transformation products in environmental samples. Analyses are performed using gas chromatography or liquid chromatography tandem mass spectrometry (GC/MS/MS or LC/MS/MS).
Professional Experience
2016-Present - Research Chemist, Mendenhall Postdoctoral Fellow, U.S. Geological Survey, California Water Science Center
2013-2015 - Interdisciplinary Science and Engineering Partnership (ISEP) Fellow, University at Buffalo
2010-2012 - Department of Chemistry Teaching Assistant, University at Buffalo
2009 - Science Undergraduate Laboratory Internship (SULI), Oak Ridge National Laboratory
2008 - Department of Chemistry Summer Internship, Allegheny College
Education and Certifications
2016 - Ph.D. in Analytical Chemistry, University at Buffalo, Buffalo, NY
2010 - B.S. in Chemistry, Allegheny College, Meadville, PA
Science and Products
A National Assessment of Pesticide, PFAS, Microplastic, and Antibiotic Resistance Gene Exposures in White-Tailed Deer
Wild Prairie Grouse Diet and Microbiomes Vary Between Cropland and Grassland Habitats
Dysbiosis, immunomodulation, and health effects of agricultural pesticides in wild prairie grouse
Pesticide Fate Research Group (PFRG)
Pesticide Concentrations Measured in Zooplankton Samples Collected from the Sacramento River and Yolo Bypass, California, 2021
Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive extraction with analysis by gas and liquid chromatography tandem mass spectroscopy
Characterizing microbiota, virulome, and resistome of wild prairie grouse in crop producing and uncultivated areas of Nebraska
Evaluation of ELISA for the Analysis of Imidacloprid in Plasma, Liver, and Fecal Matter
A Multiresidue Method for the Analysis of Pesticides in Water using Solid-Phase Extraction with Gas and Liquid Chromatography-Tandem Mass Spectrometry (ver. 2.0, April 2023)
Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive guided extraction with analysis by gas and liquid chromatography tandem mass spectroscopy
Exposure to crop production alters cecal prokaryotic microbiota, inflates virulome and resistome in wild prairie grouse
Evaluation of ELISA for the analysis of imidacloprid in biological matrices: Cross-reactivities, matrix interferences, and comparison to LC-MS/MS
Uptake, metabolism, and elimination of fungicides from coated wheat seeds in Japanese quail (Coturnix japonica)
Toxicokinetics of imidacloprid-coated wheat seeds in Japanese quail (Coturnix japonica) and an evaluation of hazard
Science and Products
- Science
A National Assessment of Pesticide, PFAS, Microplastic, and Antibiotic Resistance Gene Exposures in White-Tailed Deer
Research has documented exposures and consequential environmental health effects of pesticides, PFAS, microplastics, and antibiotic resistance genes in environmental biota. Little is known, however, regarding such effects in white-tailed deer (Odocoileus virginianus).Wild Prairie Grouse Diet and Microbiomes Vary Between Cropland and Grassland Habitats
Wild prairie grouse residing in croplands had altered diets and gut microbiome imbalances characterized by a greater abundance of pathogenic bacteria and antibiotic-resistance genes in comparison to those residing in grasslands. Similar gut microbiome imbalances are rarely associated with lethal outcomes, but rather linked to sublethal health effects including growth, development, behavior, immune...Dysbiosis, immunomodulation, and health effects of agricultural pesticides in wild prairie grouse
Agrochemical pollution poses a severe threat to biodiversity. Agrochemicals can detrimentally affect wildlife growth, development, survival, reproduction, and immune responses, which facilitates emergence and spread of infectious diseases that may cause unusually high mortality. Animal microbiota plays a fundamental role in host’s food detoxification and defense against pathogens, regulates...Pesticide Fate Research Group (PFRG)
Pesticides are applied in agricultural and urban areas to control weeds, insects, fungus, and other pests. Applied pesticides and their degradates can be transported off-site through a variety of mechanisms; these pesticides can then be found in non-target areas. Pesticide transport can occur through the atmosphere, in the aqueous phase (surface and groundwater) and associated with soil/sediment... - Data
Pesticide Concentrations Measured in Zooplankton Samples Collected from the Sacramento River and Yolo Bypass, California, 2021
Zooplankton samples were collected at one site upstream of the Yolo Bypass in Northern California, three sites within the Bypass, and at a comparison site on the Sacramento River below the city of Sacramento and analyzed for a large suite of current-use pesticides and degradates. Samples were collected every two weeks from early August 2021 to mid-October 2021. Samples were collected by towing a 1Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive extraction with analysis by gas and liquid chromatography tandem mass spectroscopy
A multiresidue method for solids (i.e., soil, sediment, sludge) was developed and evaluated for the analysis of pesticides and pesticide degradates. Initially, a well characterized soil was used to determine the recovery of target compounds using an Energized Dispersive Guided Extraction (EDGE) system with two extraction solvents, acetonitrile and 1:1 (v/v) hexane:acetone. Extracts were cleaned usCharacterizing microbiota, virulome, and resistome of wild prairie grouse in crop producing and uncultivated areas of Nebraska
Chart listing the geographic locations, NCBI numbers, voucher numbers, and microbiome characteristics of specimens collected for publicationEvaluation of ELISA for the Analysis of Imidacloprid in Plasma, Liver, and Fecal Matter
Neonicotinoids have become the most widely used insecticides in world with rapid growth in applications as seed coatings. Nontarget organisms are exposed to concentrated levels of pesticidal active ingredients through ingestion of treated seeds. To better understand pesticide fate, analytical methods are necessary to rapidly screen and accurately quantitate contaminants in environmental and biologA Multiresidue Method for the Analysis of Pesticides in Water using Solid-Phase Extraction with Gas and Liquid Chromatography-Tandem Mass Spectrometry (ver. 2.0, April 2023)
Applications of pesticides in agricultural and urban settings play an essential role in increasing crop yields, preserving food and materials, reducing pest-borne diseases, and eradicating or deterring pests. Pesticides are transported from their point of application to environmental media, including surface water. To better understand the fate of fate and transport of pesticides in the environmen - Publications
Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive guided extraction with analysis by gas and liquid chromatography tandem mass spectroscopy
The development of sample processing techniques that recover a broad suite of pesticides from solid matrices, while mitigating coextracted matrix interferences, and reducing processing time is beneficial for high throughput analyses. The objective of this study was to evaluate the effectiveness of an automated extraction system for pesticide analyses in solid environmental samples. An Energized DiAuthorsGabrielle Pecora Black, Emily Woodward, Corey Sanders, Michael S. Gross, Michelle HladikExposure to crop production alters cecal prokaryotic microbiota, inflates virulome and resistome in wild prairie grouse
Chemically intensive crop production depletes wildlife food resources, hinders animal development, health, survival, and reproduction, and it suppresses wildlife immune systems, facilitating emergence of infectious diseases with excessive mortality rates. Gut microbiota is crucial for wildlife's response to environmental stressors. Its composition and functionality are sensitive to diet changes anAuthorsSerguei Vyacheslavovich Drovetski, Brian K. Schmidt, Jonas Ethan Lai, Michael S. Gross, Michelle Hladik, Kenan Oguz Matterson, Natalie K. Karouna-RenierEvaluation of ELISA for the analysis of imidacloprid in biological matrices: Cross-reactivities, matrix interferences, and comparison to LC-MS/MS
Imidacloprid is among the most used pesticides worldwide and there are toxicity concerns for nontarget organisms. Accurate and sensitive methods are necessary to quantitate imidacloprid concentrations in biological matrices to better understand their fate and effects. Here we evaluated an enzyme-linked immunosorbent assay (ELISA) kit for the analysis of imidacloprid in biological samples. FollowinAuthorsMichael S. Gross, Emily Woodward, Michelle HladikUptake, 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 KuivilaToxicokinetics 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. Rattner