Global demand for protein-based foods is increasing due to changes in dietary choice among citizens of developed countries and, more generally, the ever-increasing human population. (1) Increased demand for affordable and nutritious meat has led to centralization and industrialization of animal feeding operations which are now common throughout North and South America, Asia, and Australia. (2) In the United States of America (USA), as of 2022, there are approximately 26,000 active beef cattle feedyards, over 2000 of which contain more than 1000 head of cattle. (3) In 2017, there were over 15 million head of cattle on feed in the USA. (4) Industrial animal feeding operations must optimize strategies for rapid and economical protein accretion while minimizing losses associated with diseases and pests that accompany extraordinarily high densities of animals and their associated waste production. (5) Cost effective veterinary pharmaceuticals including steroid growth promoters, antimicrobials, parasiticides, and a wide variety of pesticides enable profitability to be derived from the modern meat animal production model. (6) Following administration or application, residues of these agrochemicals enter the environment (7) where they may impact nontarget receptors.

Veterinary pharmaceuticals and pesticides are frequently detected in wastes produced within industrial feeding operations and subsequent surrounding environments when wastes are moved off-site intentionally or unintentionally. (8−12) Environmental contamination with animal waste and associated agrochemicals occurs via precipitation-mediated runoff and aerial dispersion. (10,13) Blackwell et al., (8) McEachran et al., (11) and Peterson et al. (12) reported occurrence of steroid growth promoters, antimicrobials and antimicrobial resistant gene sequences, and pesticides, respectively, in particulate matter (PM) (14) samples collected on or near beef cattle feeding operations (feedyards) in the Southern Great Plains, USA. Recently, this contaminated PM has been detected up to 12 km downwind of feedyards. (15) Further, a variety of pesticides and parasiticides have been detected on wildflowers, wild pollinators, (16) and in nesting matrices of wild bees and wasps (17) occurring near beef cattle feedyards in the Texas Panhandle, USA.

Since veterinary pharmaceuticals and pesticides are emitted from feedyards within fugitive PM emissions, concern has risen for potential impacts to ecological receptors occurring in landscapes receiving PM inputs, particularly pollinators. Peterson et al. (12) reported mean permethrin concentrations of 192.1 ± 117.3 ng/g in PM emitted from Texas beef cattle feedyards. When considering permethrin PM concentrations in context of the total mass of PM produced each day by USA feedyards, and the honeybee LD50 for permethrin (63 ng/bee), (18) Peterson et al. (12) calculated potential for 1 billion honeybee deaths each day. The estimate was based solely on one pesticide, not the 15 other agrochemicals detected in the same feed-yard-derived PM samples. Thus, the theoretical mortality presented by Peterson et al. (12) did not account for additivity, potentiation, or synergistic effects associated with complex pesticide mixtures. Despite numerous reports of agrochemical occurrence in fugitive feedyard PM, there are no published reports detailing the toxicity of feedyard PM to any pollinator species.

Pollinators are critical ecological service providers and are considered essential components of many trophic webs throughout the world. (19) Insect pollination services are critical for nearly 87% of angiosperm reproduction (20) and contribute to increased yield in over 75% of crops globally. (21,22) In 2012, pollination services in the USA totaled 34 billion USD. (21) Unfortunately, many pollinating insect taxa, including Lepidoptera, Coleoptera, and Hymenoptera, are in decline. (23,24) Recent estimates indicate a 20–40% reduction of crop-pollinating insect populations worldwide. (19) Among the numerous causes of declines, habitat loss, invasive species competition, and exposure to agrochemical pollutants are principal. (24) Extensive use of multiple classes of insecticides, parasiticides, and other pesticides, (24,25) are of primary concern in pollinator risk assessment efforts. (26) Furthermore, variability in pollinator species sensitivity to insecticides has recently been documented (27,28) which raises questions about adequacy of regulatory controls based on single model species tests (typically honeybees or bumblebees) and whether resulting data are sufficient for characterizing risk among all pollinators. (29−31)...