A National Assessment of Pesticide, PFAS, Microplastic, and Antibiotic Resistance Gene Exposures in White-Tailed Deer

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The Issue: As part of various management practices used to increase crop yields, farmland is the receptacle for a wide range of materials on an annual basis including: 1.1 billion tons of animal manure, 23 million tons of inorganic fertilizer, 8 million tons of municipal biosolids, and 500 tons of pesticides. These land-applied materials are known to contain a plethora of organic and inorganic contaminants including pesticides, PFAS, microplastics, and antibiotic resistant genes.

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Following land application, research has documented the presence of these contaminants in all environmental compartments including surface water, groundwater, atmosphere, soil, plant tissue, and animal tissue. In addition, there is mounting evidence of deleterious effects from contaminant exposures to both aquatic and terrestrial organisms (including humans). A paucity of research, however, has been conducted on the effects of pesticide, PFAS, microplastics, and antibiotic resistance gene exposures to large mammals such as white-tailed deer (Odocoileus virginianus). Research, however, has documented morphological and developmental abnormalities in white-tailed deer that could cause reduced survival and productivity. Possible causes for such deleterious effects include contaminant exposures from land-applied materials (e.g., pesticides, municipal biosolids, livestock manure).

Of particular note, are neonicotinoids (a class of broad-spectrum, systemic insecticides) that have rapidly become the most heavily used class of insecticides globally for both urban (e.g., lawn and garden use, companion animals) and agricultural (e.g., seed treatments, foliar spray) purposes. Neonicotinoids have a common mode of action that affects the central nervous system of insects by binding to nicotinic acetylcholine receptors making them an effective treatment against a broad range of insect pests. A previous imidacloprid exposure study demonstrated direct effects (via aqueous administration) on white-tailed deer. Nevertheless, results determined imidacloprid was present even in the organs of the control group suggesting environmental contamination. In addition, a recent study in Minnesota observed the presence of neonicotinoids in nearly all (94%) of the deer spleens analyzed. (See other resources and links below for more information.)

Addressing the Issue: To fill an important research gap regarding contaminant exposure and uptake scientists from the U.S. Geological Survey are conducting research regarding the prevalence of pesticides, PFAS, and antibiotic resistance genes in white-tailed deer. Additionally, USGS partnered with the University of Oklahoma (Dr. Mark Nanny) to investigate the prevalence of microplastics in these same deer tissues. Permitted hunters (including one tribal participant) from across the United States volunteered to obtain select deer samples (i.e., liver, spleen, and scat) following legal harvest from a range of land use and potential chemical exposures. Between September 2022 and February 2023, biological samples from 55 white-tailed deer from 24 states (Figure 1) were submitted for the study. All samples were shipped to the USGS Columbia Environmental Research Center, homogenized, split, and shipped to various laboratories for analysis (Table 1).

Study Implications

While little is known regarding potential human health effects of consuming deer meat, select states (e.g., Maine and Michigan) have issued a ‘do not eat’ advisory for white-tailed deer harvested near PFAS impacted sites as elevated levels have been found in deer meat from such impacted locations. It is hypothesized that such exposures were primarily derived from their food and water consumption (e.g., deer feeding on plants following the spreading of municipal and industrial sludge onto farmland).  

This research will assist stakeholders and decision-makers (e.g., state departments of natural resources) with determining the prevalence of high-profile contaminants in deer tissue and whether such exposures are significantly related to ancillary factors such as land use and proximity to contaminant sources (e.g., wastewater treatment plants, airports). Such information will be used to determine if additional research is needed to evaluate toxicity from such contaminant exposures.

Other resources and links:

• Berheim et al., 2019 Effects of neonicotinoid insecticides on physiology and reproductive characteristics of captive female and fawn white-tailed deer.  Scientific Reports 9, 4534 (2019).

• Hagen et al., 2019. Assessing neonicotinoids exposure in free-ranging white-tailed deer in Minnesota.

• PFAS Do Not Eat Advisory: For deer and wild turkey in portions of Fairfield and Skowhegan. Maine Department of In Fisheries and Wildlife.

• MDHHS reminds hunters of Do Not Eat health advisories for Clark's Marsh. Michigan Department of Health and Human Services (MDHHS), Michigan Depart of Natural Resources (MiDNR).

• Kolpin et al., 2021. A comprehensive statewide spatiotemporal stream assessment of per- and polyfluoroalkyl substances (PFAS) in an agricultural region of the United States: Environmental Science & Technology Letters, v. 8, no. 11, p. 981-988.

• Gray et al., 2017. Rainfall-runoff of anthropogenic waste indicators from agricultural fields applied with municipal biosolids: Science of The Total Environment, v. 580, p. 83-89.

• Yager et al., 2014. Dissipation of contaminants of emerging concern in biosolids applied to non-irrigated farmland in eastern Colorado: JAWRA Journal of the American Water Resources Association, v. 50, no. 2, p. 343-357.

• Kinney et al., 2013 Earthworm bioassays and seedling emergence for monitoring toxicity, aging and bioaccumulation of anthropogenic waste indicator compounds in biosolids-amended soil: Science of The Total Environment, v. 433, p. 507-515.

• Masoner et al., 2023. Contaminant Exposure and Transport from three potential reuse waters within a single watershed: Environmental Science & Technology, v. 57, no. 3, p. 1353-1365.

• Masoner et al., 2020. Landfill leachate contributes per-/poly-fluoroalkyl substances (PFAS) and pharmaceuticals to municipal wasterwater: Environmental Science: Water Research & Technology, v. 6, no. 5, p. 1300-1311.

• Oliver et al., 2023. Pesticide prioritization by potential biological effects in tributaries of the Laurentian Great Lakes: Environmental Toxicology and Chemistry, v. 42, no. 2, p. 367-384.

• Hanberry & Hanberry. 2019. Digitized white-tailed deer densities for the continental United States. Fort Collins, CO: Forest Service Research Data Archive.

Return to: Food Resources Lifecycle Integrated Science Team, Per-and Polyfluoroalkyl Substances (PFAS) Integrated Science Team | U.S. Geological Survey (usgs.gov), California Water Science Center, Central Midwest Water Science Center, Columbia Environmental Research Center, Oklahoma-Texas Water Science Center, Upper Midwest Water Science Center, Utah Water Science Center