Title: PIXE measurements of heavy metals of Tsunami sediment samples
1PIXE measurements of heavy metals of Tsunami
sediment samples
- John V Kennedy, Bernard Barry and Andreas
Markwitz - National Isotope Centre, Lower Hutt, New Zealand
2Outline
- Overview Experimental
- Tsunami sediment samples from Thailand
- Tsunami sediment samples from Malaysia
- Water and sediment analysis for future Marine
project Sequel - External beam scanning of complete core samples
- Summary
31. GNSs ion beam analysis facility
3 MV accelerator
Water/Air particulate analysis beam line
External PIXE beam line
MicroPIXE beam line
41. Analysis of performance of different methods
for metal measurement
Imaging capability is an additional advantage for
PIXE
52. Experimental
- 2.5 MeV protons for accelerator
- Characteristic PIXE X-rays generated by the
sample detected by a Si (Li) detector - Simultaneous detection of K X-rays of elements
such as Ba, La with a HPGe detector - PIXE spectra were analysed with GUPIX software to
determine the elemental concentration values - To detect light elements such as F, Na, and Al we
have also performed PIGE analysis at the same time
62. Tsunami sediment samples from Thailand
- Sediment samples collected by Ms.Kanitha
Srisuksawad - C1 - series of sample from moderate impact site
- C2 series of sample from low impact site
- Samples seived to collect clay only
- Pellets prepared of 10 samples of each series
along with NIST sediment standards.
Done
Not yet
Done
72. Results
Low impact
- Ti was detected at 1000-2000 ppm level in both
series with no discernable depth trends. - Ti concentration in the AOP series was about
twice that in the PMBC series - Mn concentration in the PMBC series was around
2-3 times lower than AOP
Moderate impact
82. Results
Low impact
- Fe is detected in all samples, and was found at
higher concentration in the AOP series with a
trend to higher concentration at greater depth. - Ni varies with depth
Moderate impact
92. Results
Low impact
- Zn in generally at similar concentration except
close to the surface - Sr is much higher in PMBC than AOP from both
standard and HPGe PIXE results
Moderate impact
103. Tsunami sediment samples from Malaysia
- 24 sediment samples collected in Kuala Mude by
Malaysian Colleagues (Mr.Abdul Kadir b. Ishak) - The core code is KM25A
- KM00 is core section 2 from another core, KM24B.
- Sample code KM46 is replicate of KM42.
- Sample code KM44 is SRM IAEA-405
- We have prepared 3 pellets of each samples along
with NIST sediment standards. - All the pellet samples were carbon coated in
order to avoid charging during the PIXE
measurement
113. Results
123. Results Depth information
133. Results Depth information
As
Ba
Pb
144. Water and sediment analysis for future Marine
project - Sequel
Example Waiwhetu stream, Lower Hutt, New Zealand
- Samples filtered through Nuclepore polycarbaonate
filter papers for few minutes and dried with UV - Filter papers weighed before and after filtering
the samples to determine the weight of the
filtered particles - Almost all elements detected were present in the
level of 10-100 ppm in the samples collected - Heavy metals such as Cr, Ni, Cu, Zn, Pb were
found at high level of concentrations at the
locations where most of the industries were
present. This indicates that these heavy metals
are being washed out from the sediments slowly to
surface waters - Few studies were carried out earlier in the
sediment samples indicated that there is a high
level of heavy metals (Al, Cd, Cr, Cu, Pb, Zn,
Mn, Fe) present in the sediments
V. J. Kennedy and A. Markwitz, International
Journal of PIXE Vol 12, (2002)189
154. Water and sediment analysis for future Marine
project - Sequel
165. External beam scanning of complete core samples
- Samples are often taken from geological cores and
analysed destructively for trace elements. - The effectiveness of this would be enhanced with
a technique which enabled cores to be
pre-screened quickly and non-destructively for a
range of elements at low concentrations. - Particle induced X-ray emission (PIXE) using a
proton beam is a candidate technique to fulfil
this need. - Because of the size of cores, typically in the
order of a meter long and 100 mm wide, scanning
under vacuum is impractical. Thus use of an
external beam is necessary.
175. External beam scanning of complete core samples
- Stepper motor driven slider shown without
detectors and with core in protective wrapping in
position on the slider.
185. Scanning an example core
- A sample core from the seabed near the Brothers
volcano north of the Bay of Plenty was scanned
over a distance of 200 mm at 10 mm intervals for
approximately 5 minutes per point.
195. Scanning an example core
- Core measurements for Si, Fe, Ti.
20Summary
- Some Tsunami sediment samples from Thailand and
Malaysia were analysed with PIXE. Interesting
depth information was obtained for heavy
elements. Further analysis is required on highly
effected Tsunami sites from Thailand - NAA results from Malaysia are in good agreement
with the PIXE results (see talk from Malaysia) - Ideas for water, sediment and complete core
analysis have been presented.
End.