Volume 4 Pages 1 - 45 (March 1989)

Citation: Röchert, R.. (1989) Contamination of an Otter found Dead in the F.R.G  IUCN Otter Spec. Group Bull. 4: 25 - 26

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Contamination of an Otter found Dead in the F.R.G

Ralf Röchert

Aktion Fischotterschutz, Otter Zentrum, Postbox 1216, D-3122 Hankensbüttel, West Germany

As a "by-product" of the assessment of pollution risk for the remaining otter populations in Lower Saxony (see previous article) muscle, kidney and liver tissue of a female otter (about one year old) was received and analysed for PCB, DDT and metabolites (∑-DDT), HCH-isomers, HCB and octachlorostyrene (OCS) (all muscle tissue), mercury (liver tissue), cadmium, and lead (liver and kidney tissue). The animal was killed in a road accident (July 1986) very near to the river Elbe (within 10 km) about halfway between the "disappearance" of the Elbe into the GDR and the town of Hamburg. This site is not reckoned to be part of the otter's present main distribution range.

Results:

Exceptionally high were the Hg-, HCH-, and OCS-contaminations. This does not fit well into the results of the baseline Study (see article above) but absolutely reflects the pollution pattern of the river Elbe. Many studies showed that this river is badly polluted esp. with Hg and HCB  (and with OCS) by industrial effluents. Thus the finding strongly suggests that the otter fed from fish out of the river Elbe. No otter population could possibly survive in a habitat as contaminated as this river is.  Furthermore it indicates that there is an exchange happening between East and West German otter populations via the River Elve.

The "moderate" PCB-contamination is not at all contrary to the interpretation of the risk assessment, because an enormous variability was found in all studies analysing otter tissues for PCB (see SANDEGREN et al, 1980; MASON et al., 1986; BROEKHUIZEN, 1987).  One animal cannot be taken as being representative.

By using an analytical method developed by HEIDMANN (1986), it clearly could be shown that - due to metabolisation - the composition of PCB isomers is drifting towards the high chlorinated and biologically more stable ones in the predator.

REFERENCES

Broekhuizen, S. (1987) First Data on Contamination of Otters in the Netherlands. I.U.C.N. Otter Specialist Group, Bulletin No. 2; 27 - 32
Heidmann, W. (1986) Isomer Specific Determination of Polychlorinated biphenyls in Animal Tissues by Gas Chromatography Mass Spectrometry. Chromatographia 22 (7 - 12) 363 - 369
Mason. C.F., Ford. T.C. and  Last, N.I. (1986): Organochlorine Residues in British Otters. Bulletin of Environmental Contamination and Toxicology, 36: 656 - 661
Sandegren, F., Olsson, M. and Reutergardh, L. (1980) Der Rückgang der Fischotterpopulation in Schweden, pp. 107 - 113 In Reuther, C. & Festetics, A. (1980)

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