Pergamon Chemosphere, Vol. 37, No. 13, pp. 2627-2643, 1998 © 1998Elsevier Science Ltd. All rights reserved 0045-6535/98/$ - see front matter PII: S01M5-6535(98)00162-3 VALIDATION OF THE USE OF BLOOD SAMPLES TO ASSESS TISSUE CONCENTRATIONS OF ORGANOCHLORINES IN GLAUCOUS GULLS, Larus hyperboreus Espen O. Henriksen 1., Geir W. Gabrielsen ~ and Janneche Utne Skaare 2~ J Norwegian Polar Institute, N-9005 TROMSO, Norway 2 Norwegian College of Veterinary Medicine, PO Box 8146 Dep., N-0033 OSLO, Norway 3 National Veterinary Institute, PO Box 8156, N-0033 OSLO, Norway (Receivedin Germany 18 February 1998; accepted 21 April 1998) ABSTRACT Fitteen adult glaucous gulls, Larus hyperboreus, were captured near Ny-Alesund, Svalbard. The birds were kept in captivity for 24 - 41 days and fed a diet of polar cod, Boreogadus saida. A range of organochlorines (OCs) were quantified in blood, brain, liver, and subcutaneous fat tissue. For more than 80 % of the quantified OCs, r 2 values >0.75 were found for the blood-liver concentration correlations. Repeated sampling revealed intra-individual temporal variability in blood OC concentrations. Much of the temporal variability in OC blood concentrations was associated with changes in nutritional condition. ©1998 Elsevier Science Ltd. All rights reserved -~ INTRODUCTION In recent years, disturbingly high levels of anthropogenic persistent organochlorines (OCs) have been found to bioaccumulate in arctic marine top predators [ 1,2]. The monitoring of OC levels and the studies of their possible effects depends on the analysis of tissues or body fluids. As noted by Friend and co-workers [3], the use of blood samples has several advantages compared to sacrificing animals. In endangered species, sacrificing even a few individuals may be unacceptable. Non-destructive sampling also allows long-term studies with repeated sampling and monitoring of potential impact of OCs on survival and reproduction. The use of blood as sample matrix for OC analysis depends on the assumption that the concentrations of OCs in blood are related to tissue concentrations. This assumption is supported by studies on a number of species including man (e.g. [4]), polar bear, Ursus maritimus, [1], and various birds [3,5,6]. In the case of the polychlorinated biphenyls (PCBs), regression analysis has demonstrated that the tissue:blood partition coefficient can be expressed as a function of molecular structure [7]. The present study focuses on the glaucous gull, Larus hyperboreus, an opportunistic arctic predatory gull which can accumulate high tissue concentrations of OCs, in particular PCBs [2,8]. All previous studies on OCs in the ' to whomcorrespondenceshould be addressed 2627