2,3,7,8‐tetrachlorodibenzo‐p‐dioxin equivalents in extracts of Baltic white‐tailed sea eagles

• Published in: Environmental Toxicology and Chemistry
• Main Authors: Koistinen, Janna, Koivusaari, Juhani, Nuuja, Ismo, Vuorinen, Pekka J., Paasivirta, Jaakko, Giesy, John P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: ringed seal
• Online Access: http://dx.doi.org/10.1002/etc.5620160730; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fetc.5620160730; https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.5620160730

Abstract Concentrations of 2,3,7,8‐tetrachlorodibenzo‐ p ‐dioxin‐(TCDD) equivalents were measured in extracts of Baltic white‐tailed sea eagle tissues. Extracts of salmon, ringed seal, and grey seal were analyzed as other predatory species of the same area. Concentrations in eagle and seal tissues were greater than those in salmon. Concentrations of TCDD equivalents (TCDD‐EQs) determined by the H4IIE bioassay were compared with toxic equivalents (TEQs) derived from instrumental chemical analyses in fractions containing polychlorinated dibenzo‐ p ‐dioxins and polychlorinated dibenzofurans (PCDD/PCDF) or coplanar polychlorinated biphenyls (PCBs). Toxic equivalents were calculated by use of an additive model in which the product of the concentrations of instrumentally measured individual congeners were multiplied by their TCDD equivalency factors and were summed to give a total concentration of TEQs. The TCDD‐EQs were compared with TEQs to develop a mass balance to determine whether all the TCDD‐like activity was accounted for. For example, the concentration of TCDD‐EQs in the coplanar PCB fraction of the most contaminated eagle was 980 pg/g fresh weight (fw), and that of the PCDD/PCDF fraction was 240 pg/g fw. The TEQs determined by chemical analyses for coplanar PCBs was 770 pg/g fw, and that of PCDD/PCDFs was 270 pg/g fw in this eagle. Thus, concentrations of TCDD‐EQs were approx. 20% greater than those of TEQs. The true difference in activities is probably greater because of lower recoveries and infra‐additivities among congeners in the bioassay. This indicates that there are compounds present in the extracts that can contribute to the total concentrations of TCDD‐EQs that were not accounted for by TEQs. The hazard quotient, calculated as the ratio of current concentrations of TCDD‐EQs in white‐tailed sea eagle eggs to the no‐observable‐adverse‐effect concentration, ranged from 7.3 to 141 (mean = 52.7, SD = 43). This indicates that current concentrations of TCDD‐EQs in these eggs are likely causing adverse ...