Hybrid sunflower production occurs near Sacramento in Northern California where seed treatments are commonly used. In this study, four locations were sampled in 2016 as matched pairs; half of each field was sown with thiamethoxam treated seed and half without. In addition to the thiamethoxam seed treatment, all seeds were coated with two fungicides, fludioxonil and mefenoxam/metalaxyl. Both wild bee and honey bee pesticide exposure was assessed by analyzing field soil, sunflower pollen and nectar, honey bees (pollen and nectar foraging) and a sunflower specialist wild bee, Melissodes agilis. Samples were extracted via pressurized liquid extraction (except nectar which underwent a room temperature solvent extraction) with an organic solvent followed by solid phase extraction cleanup. Samples were analyzed for 168 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. While only one of the three seed coating pesticides (thaimethoxam) was detected, 25 other pesticides and degradates were also measured. In total, 5 insecticides, 9 herbicides, 7 fungicides, and 5 degradates detected across all matrices. There were 7 pesticides and degradates detected in M. agilis, 4 in honey bees, 6 in nectar, 6 in pollen, and 23 in soil. These results indicate the bees visiting sunflower fields are exposed to more pesticides than those used as seed coatings including those pesticides applied to other nearby crops (e.g., rice, tomatoes and walnuts).

Irrigation runoff and soil samples were collected from a lettuce field located at the USDA-ARS Spence Research farm in the Salinas Valley, California to measure neonicotinoid insecticides (clothianidin and imidacloprid) and a fungicide (azoxystrobin) applied via coated seed and drench treatments. The field trial was designed to evaluate four treatments with replication: 1) control, untreated seed, 2) imidacloprid treated seed, 3) clothianidin treated seed, and 4) azoxystrobin treated seed with an imidacloprid drench. Samples were collected from each treatment over two lettuce growing seasons: August to October 2019 and September to October 2020. Runoff samples were collected over both growing seasons during 6 irrigation events each year. Surface soils were collected each year before planting and pesticide application and then again at the end of each trial. Soil cores (1 m) were collected in 2019 at the end of the that year’s trial to assess potential subsurface transport. Water samples (n=131) were filtered (0.7 µm) and extracted via solid phase extraction. Soil samples (n=106) were extracted using an accelerated solvent extraction system followed by carbon solid phase extraction. Both water and soil extracts were analyzed via liquid chromatography tandem mass spectrometry. In both years of the study, clothianidin and imidacloprid were detected in runoff and soil samples collected from each treatment. Clothianidin concentrations ranged from non-detect (ND) to 576 ng/L in runoff and ND to 29 ng/g in soil samples. Imidacloprid concentrations ranged from ND to 4877 ng/L in runoff and ND to 20 ng/g in soil samples. Imidacloprid variability between replicates was especially high in Year 2 in Treatment 4; concentrations measured in Treatment 4, Rep D were one to two orders of magnitudes higher than concentrations measured in Treatment 4 Reps A, B, and C. Azoxystrobin was also detected in runoff samples in both years and from all treatments, with concentrations ranging from ND to 237 ng/L. However, in contrast to the clothianidin and imidacloprid soil results, azoxystrobin was only detected in two soil samples during the entire two-year study (0.24 and 0.57 ng/g).

Wild bee and butterfly samples were collected from the margins of agricultural fields located on five Conservation Areas in Missouri. In 2016 and 2017, samples were collected and composited by genera for a total of 90 samples. Samples were extracted via pressurized liquid extraction and solid phase extraction cleanup. Samples were analyzed for 168 pesticides and degradates using both gas and liquid chromatography-tandem mass spectrometry. Overall, 16 pesticides were detected. Pesticides detected in greater than 2% of the composite samples included: metolachlor (24%), tebuconazole (22%), atrazine (18%), imidacloprid desnitro (13%), bifenthrin (9%), flumetralin (9%), p,p’-DDD (6%), tebupirimfos (4%), fludioxonil (4%), flutriafol (3%), cyproconazole (2%), and oxadiazon (2%). Concentrations for individual pesticides ranged from 2 to 174 ng/g. Results indicate that wild pollinators are exposed to a wide variety of pesticides.

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 150-micron conical plankton net for 5 minutes by boat at each site. In the laboratory, zooplankton samples were filtered through a 63-micrometer sieve to separate the zooplankton and vegetation/detritus from the water. Large sticks, twigs, rocks, and leaves were rinsed with organic free water into the sieve and then discarded. The remaining mass in the sieve was transferred into 50 milliliter plastic centrifuge tubes, frozen overnight at -20 degrees Celsius, dehydrated completely using a freeze dryer, and then stored at -20 degrees Celsius. Immediately prior to analysis, each freeze-dried sample was homogenized and sub-sampled to a targeted final weight of 0.5 grams. Sub-samples were further homogenized with magnesium sulfate and extracted with acetonitrile at 100 degrees Celsius using an EDGE Automated Extraction System. Extracts were cleaned up using activated carbon and evaporated to 200 microliters in acetonitrile. Each sample had internal standards added, and was analyzed by gas chromatography-tandem mass spectrometry for 29 pesticides and by liquid chromatography tandem mass spectrometry for 137 pesticides. A total of 18 pesticides were detected in the zooplankton samples, and 25 of the 31 samples collected contained multiple pesticides (maximum of 12 per sample). The most frequently detected compounds in zooplankton were azoxystrobin, bifenthrin, fluridone, p,p’-DDD, p,p’-DDE, permethrin, and thiobencarb.

Zooplankton samples were collected in the summer/fall of 2022 and 2023 at multiple sites in the Sacramento River, Yolo Bypass, and Cache Slough Region of California and analyzed for a suite of 160 current-use pesticides and pesticide degradates by the U.S. Geological Survey Organic Chemistry Research Laboratory. In 2022 samples were collected at two sites in the Bypass and at a comparison site on the Sacramento River from early August to mid-October. In 2023 zooplankton samples were collected at one site upstream of the Yolo Bypass in Northern California, four sites within the Bypass, one site downstream of the Bypass in the Cache Slough region, and at a comparison site on the Sacramento River from late July through early October. Samples were collected every two weeks by towing a 150-micron conical plankton net for 5 minutes by boat at each site. In the laboratory, zooplankton samples were filtered through a 63-micrometer sieve to separate the zooplankton and vegetation/detritus from the water. Large sticks, twigs, rocks, and leaves were rinsed with organic free water into the sieve and then discarded. The remaining mass in the sieve was transferred into 50 milliliter plastic centrifuge tubes, frozen overnight at -20 degrees Celsius, dehydrated completely using a freeze dryer, and then stored at -20 degrees Celsius. Immediately prior to analysis, each freeze-dried sample was homogenized and sub-sampled to a targeted final weight of 0.5 grams. Sub-samples were further homogenized with magnesium sulfate and extracted with acetonitrile at 100 degrees Celsius using an EDGE Automated Extraction System following procedures outlined in Black and others, (2023). Extracts were cleaned up using activated carbon and evaporated to 200 microliters in acetonitrile. Each sample had internal standards added and was analyzed by gas chromatography-tandem mass spectrometry for 27 pesticides and by liquid chromatography tandem mass spectrometry for 133 pesticides following methods described in Gross and others, (2024). A total of 15 pesticides were detected in the 18 zooplankton samples collected in 2022, and 16 of the samples contained multiple pesticides (up to 9 per sample). The most frequently detected compounds in 2022 were azoxystrobin, bifenthrin, fluridone, and p,p’-DDE. A total of 25 pesticides were detected in the 55 zooplankton samples collected in 2023, and 50 of the samples contained multiple pesticides (up to 16 per sample). The most frequently detected compounds in 2023 were azoxystrobin, bifenthrin, and p,p’-DDE.

These data were collected as part of RARE project with the Connecticut Agricultural Experiment Station. For this work, pollen was collected from honey bee colonies located at two ornamental plant nurseries in Connecticut. The pollen was analyzed for pesticide residues (type and quantity). Aggregate risk quotients for honey bee adults and larvae were calculated using these data. This dataset is associated with the following publication: Hester, K., K. Stoner, B. Eitzer, R. Koethe, and D. Lehmann. Pesticide Residues in Honey Bee (Apis mellifera) Pollen collected in Two Ornamental Plant Nurseries in Connecticut: Implications for Bee Health and Risk Assessment. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, USA, 333: 122037, (2023).

Pesticide concentrations determined in honey bee hive matrices from GC/qToF-MS analysis. Including neonicotinoid concentrations determined by LC-MS/MS as published in Lin et al., 2021. This dataset is associated with the following publication: Glinski, D., S. Purucker, J. Minucci, R. Richardson, C. Lin, R. Johnson, and W. Henderson. Analysis of contaminant residues in honey bee hive matrices. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, NETHERLANDS, 954: 176329, (2024).

Lab-reared colonies of Bombus huntii (Hunt bumble bee) were deployed in a commercial cherry orchard in the spring of 2016. A fungicide formulation containing boscalid (25.2%) and pyraclostrobin (12.8%) was applied one time at the recommended label rate. Nectar and pollen were collected daily, beginning two days before spray application and continuing for ten days following. Nectar samples were extracted with acetonitrile and cleaned up using dispersive solid-phase extraction with primary-secondary amine, C18, and magnesium sulfate. Pollen samples were extracted with ethyl acetate. Both types of samples were analyzed by GC-MS/MS for boscalid and pyraclostrobin. Fungicide concentrations in nectar varied spatially (by hive) and temporally. Individual pollen balls were visually identified as to primary and secondary plant sources. Pollen primarily from cherries contained the highest concentrations of the fungicides. There are 2 csv sets related to this data release.

These data represents annual estimates of neonicotinoid nitroguanidine group insecticide application rates across the western conterminous United States from 2008 to 2014. This product contains seven raster layers (appearing as separate bands in a multi-band raster). Each band represents one year of the data beginning in 2008. Estimates are generated by pairing crop specific application rates of neonicotinoids with fine scale crop data obtained from the CropScape cropland data layer. Application units are kilograms per hectare. Further details on the methods used to generate this product are described in: Douglas, M.R., Baisley, P., Soba, S., Kammerer, M., Lonsdorf, E.V. and Grozinger, C.M., 2022. Putting pesticides on the map for pollinator research and conservation. Scientific Data, 9(1),1-15. This data layer was originally generated for use in an assessment of environmental stressors on the occupancy of the western bumble bee and supports the pre-listing science for this species under consideration by the U.S. Fish and Wildlife Service. For more information on that assessment see the publication listed in the Larger Works Cited Section.

Hydrophobic (sediment-associated) pesticides were measured in sediment samples collected from 82 wadeable streams and in biofilm in 54 of those streams in the Central California Foothills and Coastal Mountains ecoregion.115 current-use and 3 legacy pesticides were measured in stream sediment; 93 of the current-use pesticides and the same 3 legacy pesticides were measured in biofilm. On average 4 times as many current-use pesticides were detected in biofilm at a site (median of 2) as in sediment (median of 0.5). This data release provides data for the pesticide concentrations, information on the pesticide compounds, and input data and R scripts for statistical models used in the analysis presented in the journal article "Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities," by BJ Mahler, TS Schmidt, LH Nowell, SL Qi, PC Van Metre, ML Hladik, DM Carlisle, MD Munn, and J May, http://dx.doi.org/xxxxxxxx.