Pesticide residues in honey bee (Apis mellifera) pollen collected in two ornamental plant nurseries in Connecticut: Implications for bee health and risk assessment

K P Hester; K A Stoner; B D Eitzer; R W Koethe; D M Lehmann

doi:10.1016/j.envpol.2023.122037

Pesticide residues in honey bee (Apis mellifera) pollen collected in two ornamental plant nurseries in Connecticut: Implications for bee health and risk assessment

Environ Pollut. 2023 Sep 15:333:122037. doi: 10.1016/j.envpol.2023.122037. Epub 2023 Jun 20.

Authors

K P Hester¹, K A Stoner², B D Eitzer², R W Koethe³, D M Lehmann⁴

Affiliations

¹ Center for Public Health and Environmental Assessment, Health and Environmental Effects Assessment Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA.
² Retired, Connecticut Agricultural Experiment Station, New Haven, CT, 06504, USA.
³ Region 1 Office, Land, Chemicals and Redevelopment Division, RCRA Waste, Underground Storage Tanks and Pesticides Section, U.S. Environmental Protection Agency, Boston, MA, 02109, USA.
⁴ Center for Public Health and Environmental Assessment, Health and Environmental Effects Assessment Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA. Electronic address: Lehmann.David@epa.gov.

PMID: 37348699
PMCID: PMC10732578 (available on 2024-09-15)
DOI: 10.1016/j.envpol.2023.122037

Abstract

Honey bees (Apis mellifera L.) are one of the most important managed pollinators of agricultural crops. While potential effects of agricultural pesticides on honey bee health have been investigated in some settings, risks to honey bees associated with exposures occurring in the plant nursery setting have received little attention. We sought to identify and quantify pesticide levels present in honey bee-collected pollen harvested in two ornamental plant nurseries (i.e., Nursery A and Nursery B) in Connecticut. From June to September 2018, pollen was collected weekly from 8 colonies using bottom-mounted pollen traps. Fifty-five unique pesticides (including related metabolites) were detected: 24 insecticides, 20 fungicides, and 11 herbicides. Some of the pesticide contaminants detected in the pollen had not been applied by the nurseries, indicating that the honey bee colonies did not exclusively forage on pollen at their respective nursery. The average number of pesticides per sample was similar at both nurseries (i.e., 12.9 at Nursery A and 14.2 at Nursery B). To estimate the potential risk posed to honey bees from these samples, we utilized the USEPA's BeeREX tool to calculate risk quotients (RQs) for each pesticide within each sample. The median aggregate RQ for nurse bees was 0.003 at both nurseries, well below the acute risk level of concern (LOC) of ≥0.4. We also calculated RQs for larvae due to their increased sensitivity to certain pesticides. In total, 6 samples had larval RQs above the LOC (0.45-2.51), resulting from the organophosphate insecticide diazinon. Since 2015, the frequency and amount of diazinon detected in pollen increased at one of our study locations, potentially due to pressure to reduce the use of neonicotinoid insecticides. Overall, these data highlight the importance of considering all life stages when estimating potential risk to honey bee colonies from pesticide exposure.

Keywords: Apis mellifera; Honey bee; Honeybee; Ornamental plant nursery; Pesticide; Risk assessment; Risk quotient.

Published by Elsevier Ltd.

MeSH terms

Animals
Bees
Connecticut
Diazinon / analysis
Gardens
Insecticides* / analysis
Insecticides* / toxicity
Pesticide Residues* / analysis
Pesticides* / analysis
Pesticides* / toxicity
Pollen / chemistry
Risk Assessment

Substances

Pesticide Residues
Insecticides
Diazinon
Pesticides

Grants and funding

EPA999999/ImEPA/Intramural EPA/United States