Comparison and Contrast of Elemental Components of Urban and

Comparison and Contrast of Elemental Components
Of Urban and Rural Honey Bees in Saskatchewan
B. WOLKOWSKI, M. WENKOFF, T. JOHNSON, A. SIAOTONG, and T. MOLNAR
R.I.R. BLYTH, D. MUIR, J. THOMPSON, J. MCBETH, and T. WALKER 2
1 University of Saskatchewan College of Education, Saskatoon, Canada
2 Canadian Light Source, Inc., Saskatoon, Canada
III. METHODOLOGY
Sample
preparation
Figure 1. Specimen and silicon drift detector
(Vortex-EM®, Hitachi High-Technologies Science America,
Northridge, CA, USA) of the
X-ray fluorescence (XRF) spectroscopy system
The health of honey bees has been of concern lately
because of the rapid decline of honey bee populations due
to colony collapse disorder (Cox-Foster and
.
vanEngelsdorp
2009). Using X-ray fluorescence (XRF)
spectroscopy (Figure 1) at the IDEAS beamline of the
Canadian Light Source synchrotron, concentrations of
active elemental ingredients of common pesticides and
other environmental stressors (pollens from genetically
modified crops, the adult bee physiology and pathogen
loads)(vanEngelsdorp et al. 2009) were investigated.
Samples consisted of bee abdomen and bee legs from
both an urban bee farm in Saskatoon, SK and a rural bee
farm outside of the city. A few of these samples were
placed in a vacuum to remove the presence of argon from
the spectra. Additional samples of honey, comb, and wax
from the rural bee hives were also analyzed using XRF.
There was an expectation of a large concentration
of said elemental components in most bees due to their
low tolerance to many toxic chemicals, hence, providing a
potentially sensitive indication of pollutant-induced harm
(Bromenshenk 1985).
X-ray fluorescence
regular scans
IV. RESULTS
• Bee abdomen and legs were removed from both
urban and rural bees.
• Rural and urban bees were prepared separately to
eliminate possible cross contamination.
• Samples were prepared from three bees, put into
sample holders, and held in place with Kapton tape
and labelled with a letter starting from A.
• A control sample of Kapton tape was prepared as
well in a sample holder.
• Regular scans were taken with an exposure time of
180s with photon energy level of 10 KeV at high
resolution to improve peak definitions of:
• 6 urban bee abdomens
• 7 rural bee abdomens
• 4 urban bee legs
• 4 rural bee legs
• 1 control sample (Kapton tape)
X-ray fluorescence
under-vacuum
scans
Analysis
• Scans were taken at an exposure time of 30 minutes
to reduce the presence of argon (Ar) peaks in scans
caused by the air surrounding the following samples:
• 1 urban bee abdomen
• 1 rural bee abdomen
• 1 control sample (Kapton tape)
• The control scans were subtracted from the sample
scans to remove background noise.
• The scans of urban and rural bees’ abdomens and
legs were then normalized (based on the iron peaks)
to allow for heights of the peaks to be compared.
• Average scans of urban and rural bees’ abdomens
and legs were analyzed to find the elemental
components corresponding to the peaks.
• The two (urban and rural) under-vacuum scans were
compared as well.
a.To qualitatively investigate the elemental components
of urban and rural honey bees using the X-ray
fluorescence spectroscopy at the IDEAS beamline of the
Canadian Light Source synchrotron
a.To quantitatively compare and contrast the
concentrations of the aforementioned chemical species
found within the abdomen and legs of honey bees
collected from urban and rural hives
Figure 2. Preparation of bee abdomen
and leg samples
Figure 3. Bee abdomen samples in
sample holders and Kapton tape.
a. The elemental components of urban and rural honey
bees are potassium (K), calcium (Ca), chromium (Cr),
manganese (Mn), iron (Fe), nickel (Ni), copper (Cu),
and zinc (Zn).
b. Urban bees have higher levels of K and Cu while rural
bees have elevated concentrations of Cr, Ni, and Zn.
However, Mn and Fe have the same amount for both
urban and rural bees.
c. Elevated concentrations of Cr, Ni and Zn in rural bees
may be attributed to the differentiated elemental
components of urban and rural pollens. In the study of
Bermudez et al. (2011) the mean wheat grain
concentrations of Cr, Cu, Fe, Mn and Zn surpassed the
tolerance limits stated in the international legislation
for wheat grain and foodstuffs.
Rural Normalized,
Background Removed
Fe
0.9
Urban Normalized,
Background Removed
0.8
0.7
Zn
0.6
0.5
0.4
K
0.3
Cr
0.2
Mn
Ca
VI. TEACHING IMPLICATIONS
Fe
Cu
0.1
II. OBJECTIVES
b.To identify the possible sources of the differentiated
levels of concentration of the elemental components of
urban and rural honey bees
V. CONCLUSIONS
1
Normalized Photon Count
I. INTRODUCTION
1
Ni
0
2000
3000
4000
5000
6000
7000
8000
9000
Energy (eV)
10000
The experience and appreciation of the
scientific method, research, and hands on learning,
especially the use of the synchrotron, will instill in us a
passion to share the same with our students through
inquiry method, problem-based learning, scientific
experimentation, and practical real world applications.
Figure 4. X-ray fluorescence of urban and rural
honey bees under vacuum
Figure 4 depicts the x-ray fluorescence scans of urban
and rural honey bees under vacuum. The significant peak at
3300 electron volts (eV) shows the presence of potassium in
both samples. The peak at 3650 eV and 4000 eV can be
attributed to calcium (Ca). Supporting this theory further is
the peak being nearer to 3700 eV in the urban bee line
because of its lower level of K.
The peak at 5400 eV can be attributed to
chromium (Cr) while that at 5890 eV to manganese (Mn).
Peaks at 6380 eV and 7020 eV indicate the presence of iron
(Fe) within the sample. The peak at 7460 eV shows the
presence of nickel (Ni). This is further supported by the
presence of a slight peak at 8260 eV. The peak at 8020 eV can
be identified as copper (Cu) with a peak at 8900 eV
supporting this. The peaks at 8630 eV and 9570 eV can be
identified as zinc (Zn).
For the urban bees, the concentration of K is higher
than that of the rural bees. The Ca content is virtually
identical due to the peak at 4000 eV and the overlapping
peaks at 3650 eV could be why the urban peak is higher due
to the potassium. Moreover, the Cu peak suggests a higher
amount in urban bees. For the rural bees, the concentrations
of Cr, Ni, and Zn are higher compared with the urban bees.
The Mn concentration is the same for both and the
reason for the rural line being higher at 5890 eV is due to
Cr’s second peak at 5940 eV. This also accounts for the slight
shift to the right with the rural peak. Fe is virtually identical
in both rural and urban.
Figure 5. Checking the sample of bee legs
and beamline using webcam.
REFERENCES
Bermudez, G., R. Jasan, R. Pla, M.L. Pignata. 2011. Heavy metal and trace
element concentrations in wheat grains: Assessment of potential noncarcinogenic health hazard through their consumption. Journal of Hazardous
Materials 193: 264-271
Bromenshenk, J., S. Carlson, J. Simpson, J. Thomas. Pollution monitoring of
Puget Sound with honey bees. Science 227.
Cox-Foster, D. and D. vanEngelsdorp. 2009. Saving the honeybee. Scientific
American 300:40-47.
vanEngelsdorp, D. et al. 2009. Colony collapse disorder: A descriptive study.
PLoS One 4(8).
ACKNOWLEDGEMENTS
Canadian
Light
Source,
Inc.
Saskatoon/Langham
[email protected]
(306)274-8880
Dr. Barry
Brown,
Professor
Emeritus
Bar 2 Bee
Honey
Ranch
College of Education,
University of
Saskatchewan

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