1. Michael Raessler, Jan Rothe and Ines Hilke
Determination of Al, Cd, Cr, Cu, Fe, Mn, Ni and Zn in woodlice and their skins – Is moulting a means of decontamination?
Michael Raessler, Jan Rothe and Ines Hilke
Max-Planck-Institut fuer Biogeochemie, Hans-Knoell-Strasse 10, D Jena, Germany

2. Why analyzing woodlice and their skins?
They are:
good bioindicators;
widespread throughout rural and urban areas in Central Europe;
relatively large, conspicous and easily collected;
show a high tolerance for heavy metals;
accumulate heavy metals efficiently in their hepatopancreas;
can be reared under standardized conditions;

3. Sample preparation
Woodlice were cultivated under standardized conditions in a climatic chamber at T= 22°C and a humidity of > 90%
Animals were fed with carrots and lettuce from the same supplier; no additional water was provided
The density of the population was regularly checked to avoid trophic enrichment of minerals by cannibalism
After 1 year, 15 animals (30 – 40 mg dry weight) per species of the same age and size were picked out manually
Animals were killed by cooling to – 18°C
Animals were freeze-dried, pooled and ground

4. Skin of Animals
Separately and manually collected after moulting every 2 – 3 weeks
Pooled samples from 6 months of skin collection were dried and ground
Subsamples of 50 mg (10 – 12 skins of adult woodlice) were used for digestion and analysis

5. Sample Digestion
Microwave-assisted high pressure digestion (Multiwave, Anton Paar, Graz, Austria)
Sample weight: 100 mg (woodlice and reference material ) mg (skin samples)
3 mL nitric acid (HNO3), 65%, suprapur (Merck, Damrstadt, Germany)
A blank was run with each series to check for possible contamination of reagents and vessels
Digested samples were transferred to 50 mL glass vessels for analysis by ICP-OES

6. Reference Materials Dorm-2, Dogfish muscle (Squalus acanthias) SRM 1577b, BOVINE LIVER were selected to respond the following requests:
To match the animal matrix as closely as possible
To contain the elements under consideration in a concentration range which was both expected in the animals and also accessible to ICP-OES after digestion and dilution
To contain certain elements in both standards for double control (Cu, Fe, Mn, Zn)

7. Analysis by ICP-OES (1) Plasma Gas 15 L/min Auxiliary Gas 0,5 L/min
RF power watts
Plasma Gas L/min
Auxiliary Gas 0,5 L/min
Nebulizer Gas 0,8 L/min
Pump Rate 1,3 L/min
Nebulizer Cross-flow
Spray Chamber Scott-type, Ryton
Plasma View Axial
Viewing Distance 15 mm
Optima 3300 DV, Perkin Elmer, Norwalk, CT, USA

8. Analysis by ICP-OES (2) Element WL [nm] LOD [µg/L] LOQa [µg/kg] Al
396,152
0,8
400 Cd
226,502
0,4
200 Cr
267,716 Cu
224,700
1,0
500 Fe
259,940
0,3
150 Mn
259,372
0,1 50 Ni
231,604 Zn
213,857
0,5
250

9. Results of Dorm-2 Element Certified Concentration [mg/kg]
Tolerance [mg/kg]
Analysis [mg/kg]
SD [mg/kg] Al
10,9
1,7
12,1
0,9 Cr
34,7
5,5
29,6 1 Cu
2,34
0,16
2,32
0,23 Fe
142 10
135,9 5 Mn
3,66
0,34
4,01
0,18 Ni
19,4
3,1
19,5
0,3 Zn
25,6
2,3
26,6
0,4

10. Results of Bovine Liver
Element
Certified Concentration [mg/kg]
Tolerance [mg/kg]
Analysis [mg/kg]
SD [mg/kg] Cd
0,50
0,03
0,51
0,02 Cu
160 8
163 1 Fe
184 15
187 3 Mn
10,5
1,7
10,7
0,2 Zn
127 16 2

11. Analyses of P. scaber and their Skins
Element
Animal [mg/kg]
SD [mg/kg]
Skins [mg/kg] Al
229
0,5
631
6,4 Cd
2,58
0,04
< 0,2 Cr
2,02
0,08
3,04
0,2 Cu
171
2,8
8,4
0,1 Fe
249
1,4
502
2,1 Mn
77,6
0,4
142
0,8 Ni
4,02
9,9 Zn
170
28,2
1,1

12. Analyses of P. dilatatus and their Skins
Element
Animal [mg/kg]
SD [mg/kg]
Skins [mg/kg] Al
621
2,1
922
6,3 Cd
0,99
0,06
< 0,2 Cr
4,63
0,1
13,8
0,6 Cu
116
2,8
9,1
0,8 Fe
642
7,1
969
7,0 Mn 77
1,4
125
1,3 Ni
4,16
28,3
1,5 Zn
97,6
0,5
32,3

13. Comparison of P. scaber and P. dilatatus

14. Conclusions Enrichment in skins for Al, Cr, Fe, Mn and Ni
No enrichment in skins observed for Cd, Cu and Zn
Moulting is a possible means of decontamination in both P. scaber and P. dilatatatus for Al, Cr, Fe, Mn and Ni, but not for Cd, Cu and Zn

15. Acknowledgement Many thanks to Silja Ursel and Kristin Lober, FSU Jena
And to all