Table 1. The mean, median and range of concentrations for 32 pesticide active ingredients detected in pollen samples collected from honey bee colonies over a 16-week period.
| Chemical | Pesticide type |
Site 1: non-agricultural area |
Site 2: untreated maize |
Site 3: treated maize |
LOD (p.p.b.) | |||
|---|---|---|---|---|---|---|---|---|
| % of samples detected (n=30) | Mean, median conc. (p.p.b.) | % of samples detected (n=24) | Mean, median conc. (p.p.b.) | % of samples detected (n=32) | Mean, median conc. (p.p.b.) | |||
| Carbaryl | Carbamate | 6.67% | <LOD, 0.0(0.12–0.30) | 8.33% | 0.07, 0.0(0.20–1.45) | 25% | 0.52, 0.0 (0.09–10.55) | 0.02 |
| Methomyl | 6.67% | <LOD, 0.0 (0.12–0.15) | 4.17% | 0.09, 0.0 (2.07–2.07) | 9.38% | <LOD, 0.0 (0.17–0.63) | 0.09 | |
| Azoxystrobin | Fungicide | 93.33% | 1.63, 0.868 (0.1–10.39) | 87.5% | 1.90, 0.92 (0.10–8.32) | 87.5% | 2.39, 0.66 (0.09–28.31) | 0.08 |
| Difenoconazole | 6.67% | 0.39, 0.0 (4.65–6.93) | 12.5% | 0.21, 0.0 (0.54–2.73) | 6.25% | <LOD, 0.0 (0.35–0.68) | 0.14 | |
| Dimoxystrobin | 20% | 0.01, 0.0 (0.02–0.10) | 8.33% | 0.003, 0.0 (0.01–0.05) | ND | . | 0.002 | |
| Metalaxyl | 26.67% | 0.09, 0.0 (0.03–1.45) | 33.33% | 0.09, 0.0 (0.03–0.68) | 31.25% | 0.05, 0.0 (0.03–0.42) | 0.004 | |
| Propiconazole | 23.33% | 0.25, 0.0 (0.47–2.26) | 37.5% | 0.57, 0.0 (0.12–4.34) | 21.88% | 0.52, 0.0 (0.34–6.57) | 0.05 | |
| Pyraclostrobin | 36.67% | 1.74, 0.0 (0.05–12.0) | 33.33% | 1.73, 0.0 (0.62–11.67) | 28.13% | 2.32, 0.0 (0.61–31.46) | 0.04 | |
| Trifloxystrobin | 63.33% | 0.97, 0.156 (0.03–15.16) | 62.5% | 0.52, 0.16 (0.02–6.83) | 65.63% | 0.35, 0.11 (0.03–3.32) | 0.02 | |
| 2,4–D | Herbicide | ND | . | 12.5% | <LOD, 0.0 (4.08–12.39) | ND | . | 1.44 |
| Acetochlor | 10% | 0.14, 0.0 (0.36–2.99) | 25% | 0.36, 0.0 (0.13–3.33) | 34.38% | 2.12, 0.0 (0.28–25.38) | 0.12 | |
| Atrazine | 20% | 0.82, 0.0 (0.42–7.29) | 54.17% | 1.63, 0.43 (0.33–14.88) | 43.75% | 4.66, 0.0 (0.21–45.26) | 0.02 | |
| Chlorimuron–ethyl | 6.67% | 0.30, 0.0 (3.51–5.35) | 20.83% | 0.25, 0.0 (0.46–1.97) | 15.63% | 0.11, 0.0 (0.20–1.38) | 0.04 | |
| Metolachlor | 83.33% | 0.33, 0.13 (0.01–2.45) | 75% | 0.36, 0.20 (0.20–1.45) | 71.88% | 0.58, 0.11 (0.01–7.13) | 0.003 | |
| DEET | Repellent | 100% | 3.82, 1.37 (0.10–21.12) | 100% | 2.48, 0.82 (0.08–20.33) | 100% | 2.91, 0.55 (0.07–26.20) | 0.004 |
| Methoxyfenozide | Insect growth regulator | 3.33% | <LOD, 0.0 (0.16–0.16) | 8.33% | 0.06, 0.0 (0.48–0.91) | 9.38% | 0.35, 0.0 (0.42–10.25) | 0.06 |
| Spinetoram | Fermentation product insecticide | 10% | <LOD, 0.0 (0.10–1.03) | 16.67% | <LOD, 0.0 (0.13–0.46) | 15.63% | <LOD, 0.0 (0.10–0.75) | 0.08 |
| Spinosad | 6.67% | 0.06, 0.0 (0.87 –1.01) | 8.33% | 0.05, 0.0 (0.57–0.64) | 9.38% | 0.03, 0.0 (0.16–0.44) | 0.03 | |
| Acetamiprid | Neonicotinoid | ND | . | 12.5% | 0.04, 0.0 (0.07–0.65) | 28.13% | 0.32, 0.07 (0.04–4.69) | 0.03 |
| Clothianidin | 3.33% | 0.16, 0.0 (4.66–4.66) | 16.67% | 0.20, 0.0 (0.70–1.79) | 21.88% | 0.66, 0.0 (0.64–9.37) | 0.09 | |
| Dinotefuran | 10% | <LOD, 0.0 (4.85–6.31) | 4.17% | <LOD, 0.0 (4.08–4.08) | 3.13% | <LOD, 0.0 (4.52–4.52) | 0.97 | |
| Imidacloprid | 6.67% | <LOD, 0.0 (0.94–1.05) | ND | . | ND | . | 0.69 | |
| Thiacloprid | ND | . | 4.17% | <LOD, 0.0 (0.39–0.39) | 3.13% | <LOD, 0.0 (0.25–0.25) | 0.12 | |
| Thiamethoxam | 10% | 0.12, 0.0 (0.52–1.69) | 33.33% | 0.23, 0.0 (0.18–1.82) | 21.88% | 0.08, 0.0 (0.07–0.95) | 0.04 | |
| Coumaphos | Organophosphate | 16.67% | 0.32, 0.0 (0.70–4.21) | 20.83% | 0.25, 0.0 (0.25–4.05) | 9.38% | <LOD, 0.0 (0.26–1.44) | 0.24 |
| Diazinon | 10% | 0.13, 0.0 (0.15–2.22) | 16.67% | 0.08, 0.0 (0.20–0.74) | 15.63% | 0.04, 0.0 (0.08–0.43) | 0.007 | |
| Dimethoate | 3.33% | 0.01, 0.0 (0.34–0.34) | 20.83% | 0.08, 0.0 (0.03–1.43) | 15.63% | <LOD, 0.0 (0.12–0.14) | 0.01 | |
| T-Fluvalinate | Pyrethroid | 10% | <LOD, 0.0 (2.31–14.48) | 4.17% | <LOD, 0.0 (5.88–5.88) | ND | . | 1.13 |
| Phenothrin | 30% | 47.6, 0.0 (34.92–343.76) | 16.67% | 84.5, 0.0 (250.39–728.85) | 28.13% | 195.4, 0.0 (274.13–1,955) | 1.28 | |
| Prallethrin | 46.67% | 29.0, 0.0 (6.49–236.78) | 25% | 5.53, 0.0 (5.59–55.06) | 15.63% | 5.88, 0.0 (7.24–144.46) | 0.68 | |
| Tetramethrin | 6.67% | 0.15, 0.0 (0.70–4.10) | 8.33% | 0.04, 0.0 (0.18–0.68) | 6.25% | 0.02, 0.0 (0.30–0.42) | 0.02 | |
| λ-Cyhalothrin | 10% | 0.22, 0.0 (1.39–3.39) | 16.67% | 0.37, 0.0 (0.16–5.69) | 12.5% | 0.50, 0.0 (0.103–6.13) | 0.005 | |
DEET, N,N-Diethyl-meta-toluamide; LOD, limit of detection; ND, not detected.
Colonies were placed in a non-agricultural area, adjacent to a maize field grown from untreated seed and adjacent to a maize field grown from seed treated with neonicotinoids and fungicides.