Fig 1.
Conceptual biphasic decay of anticipated brodifacoum residues over time.
Accumulation during bait applications (black), rapid decline following application peaks as residues are purged from the ecosystem by flushing, metabolism, etc. (gray), and long-term persistence of lower decay rates as bound residues (e.g., in liver tissues) decay naturally (white). Numbers represent sampling intervals over time.
Fig 2.
Food web documenting the potential focal pathways of brodifacoum transfer within the environment on Midway Atoll.
Table 1.
Summary table of environmental monitoring samples by compartment processed for brodifacoum residues over time within dedicated sampling intervals on Midway Atoll, Northwestern Hawaiian Islands, 2022–2024.
Table 2.
Mean brodifacoum residue levels in invertebrates (pooled collection, Protaetia pryeri, Blattaria spp., and Ocypode pallidula) collected systematically on Sand Island, Midway Atoll, Northwestern Hawaiian Islands, 2022–2024. MLOD is method limit of detection; MLOQ is method limit of quantitation; ND is not detected. N/A (not applicable) is listed where there was no brodifacoum detected or only one sample analyzed.
Fig 3.
Mean brodifacoum residues in pooled invertebrate samples over time on Midway Atoll, Northwestern Hawaiian Islands, from July 2022 to August 2024.
Error bars represent 95% confidence intervals within sample periods. Mean trendline is shown as a bold line. The analytical method limit of detection (range: 0.94–1.90 ng/g) is shown as a dotted line. Y-axis is broken to display high variation in values.
Fig 4.
Mean brodifacoum residues with ghost crab (Ocypode pallidula) samples over time on Midway Atoll, Northwestern Hawaiian Islands, from July 2022 to August 2024.
Error bars represent 95% confidence intervals within sample periods. Mean trendline is shown as a bold line. The analytical method limit of detection (range: 0.94–1.90 ng/g) is shown as a dotted line.
Table 3.
Mean brodifacoum residue levels in the soil, water, reptile, and contingency samples collected systematically on Sand Island, Midway Atoll, Northwestern Hawaiian Islands, 2022–2024. MLOD is method limit of detection; MLOQ is method limit of quantitation; ND is not detected. N/A (not applicable) is listed where there was no brodifacoum detected or only one sample analyzed.
Table 4.
Mean brodifacoum residue levels in the plant, soil, and water samples collected systematically on Sand Island, Midway Atoll, Northwestern Hawaiian Islands, 2022–2024. MLOD is method limit of detection; MLOQ is method limit of quantitation; ND is not detected. N/A (not applicable) is listed where there was no brodifacoum detected or only one sample analyzed.
Table 5.
Mean brodifacoum residue levels in fish collected systematically on Sand Island on Midway Atoll, Northwestern Hawaiian Islands, 2022–2024. MLOD is method limit of detection; MLOQ is method limit of quantitation; ND is not detected. N/A (not applicable) is listed where there was no brodifacoum detected or only one sample analyzed.
Fig 5.
Mean brodifacoum residues with western mosquitofish (Gambusia affinis) samples over time on Midway Atoll, Northwestern Hawaiian Islands, from July 2022 to August 2024.
Error bars represent 95% confidence intervals within sample periods. Mean trendline is shown as a bold line. The analytical method limit of detection (range: 1.20–1.90 ng/g) is shown as a dotted line.
Table 6.
Mean brodifacoum residue levels in carcasses collected (shorebirds, seabirds, ducks, egrets, passerines, fish, and invertebrates) on Midway Atoll, Northwestern Hawaiian Islands. Livers were analyzed for all avian samples. MLOD is method limit of detection; MLOQ is method limit of quantitation; ND is not detected. N/A (not applicable) is listed where there was no brodifacoum detected or only one sample analyzed.
Fig 6.
Number of bird carcasses (excluding albatross species) found on standardized carcass transects on Midway Atoll, Northwestern Hawaiian Islands, from June 2023 to October 2023.