Grandjean, P.

Hoppe, H.-W.

Weihe, P.

University of Southern Denmark Research Output

Syddansk Universitet
Sustained high concentrations of PCBs in Faroese pregnant women despite dietary
intervention
Weihe, Pál; Hoppe, H.-W.; Grandjean, Philippe
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Organohalogen Comp
Publication date:
2003
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Citation for pulished version (APA):
Weihe, P., Hoppe, H-W., & Grandjean, P. (2003). Sustained high concentrations of PCBs in Faroese pregnant
women despite dietary intervention. Organohalogen Comp, 63, 389-392.
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SUSTAINED HIGH CONCENTRATIONS OF PCBs IN FAROESE 
PREGNANT WOMEN DESPITE DIETARY INTERVENTION 
 
 
Pál Weihe1, 2, Hans-Wolfgang Hoppe,3 Philippe Grandjean2, 4 
 
1 Department of Occupational and Public Health, 110 Tórshavn, The Faroe Islands. 
2 Institute of Public Health, University of Southern Denmark, 5000 Odense, Denmark 
3 Labor Dr. Schiwara & Partner, 28357 Bremen, Germany 
4 Department of Environmental Health, Harvard School of Public Health, Boston, MA 02118, 
USA 
 
 
Introduction 
Faroe Islanders have consumed pilot whales since Medieval times. However, the pilot whale meat 
has been found to be contaminated with methylmercury and the blubber with POPs, including 
PCB and DDE. Since 1985 investigations have therefore been carried out in the Faroe Islands to 
establish the exposure levels in pregnant women and the potential adverse effects of the pollutants 
on the fetus. Current evidence from the Faroes indicates that prenatal exposure to methylmercury 
and, to a lesser degree, PCBs may impair fetal and childhood development. In August 1998, the 
Faroese health authorities therefore advised women to reduce their intake of pilot whale meat and 
blubber to protect the fetus against adverse effects from these food contaminants. This study 
describes the serum PCB concentrations of consecutive groups of pregnant women before and 
after the advisory. 
 
Methods and Materials 
Pre-Advisory Cohort 
During 1994-1995, a cohort was collated of 182 pregnant women during a 12-month period1, 2. 
The women were living in the central and northwestern Faroe Islands, excepting the capital of 
Tórshavn. About 64% of all pregnancies in the area were included. A brief dietary questionnaire 
was filled in on intake of whale meat and blubber, and other foods during pregnancy. Maternal 
serum was obtained from 173 of the women at the last antenatal consultation at pregnancy week 
34. The serum was analyzed at the National Center for Environmental Health, Centers for Disease 
Control, by a two-stage solid-phase extraction followed by gas chromatography analysis with 
electron capture detection3. 
 
Post-Advisory Cohort 
This cohort was also gathered during a 12-month period, i.e., during 2000-2001. This report 
presents the first results from this study. Two individuals served as interviewers, a clinical 
dietician and a midwife. During this period, a total of 486 pregnant women were eligible for 
inclusion, and 298 (65.6%) were invited to participate, of whom 189 (66.4%) agreed to participate. 
However, 8 subjects (2.7%) did not want to continue, 14 (4.7%) did not approve the blood 
sampling, and 19 (6.4%) accepted to participate but were not included because of scheduling 
problems. The final number of participants was 148 (49.7%). 
 
Organohalogen Compounds, Volumes 60-65, Dioxin 2003 Boston, MA
  
To cover the daily dietary variations we used 24-hour recall interviews (24 h recall), as well as a 
food diary (FD), where all food consumed during one day at a time was reported by each woman. 
These registration sheets were in accordance with the previously performed dietary survey in the 
Faroes4. We interviewed the women at home when they were in 28th, 33rd and 38th weeks of 
pregnancy. All together we obtained 409 24-h recall interviews (116 women completed all three 
interviews, 29 did two, and 3 women only one interview). A total of 732 FD recordings were 
collected (average of five FDs per woman). 
 
Sample Analysis 
Blood samples from the post-advisory cohort were taken at week 37. The analytical procedure 
used have been described previously5. Briefly, an aliquot (2 ml) of the serum was spiked with a 
solution of internal standards (delta-HCH, 13C6-p,p-DDE and six 13C6-PCBs) and was shaken for 1 
minute with formic acid (2 ml). The analytes were subsequently extracted into 10 ml of a mixture 
of toluene/n-hexane (1:1, v/v). After centrifugation, the organic phase was transferred into a glass 
tube and evaporated to approximately 100 to 500 µl in a vacuum centrifuge. The concentrated 
extracts were purified using silica gel (Silica Gel 60 from Merck) and a mixture of toluene/n-
hexane (1:4, v/v) as eluent. Calibration standards prepared in bovine plasma were processed and 
measured in the same manner as the samples to be analyzed. Sample analysis was performed on a 
Hewlett-Packard gas chromatograph (HP 5890 II) interfaced with a mass spectrometer (MS 
Engine 5989A). Operating conditions were as follows: GC inlet: split-splitless, splitless injection 
(2 µl) with injector at 250°C; GC column, DB-5 (30m x 0.25 mm x 0.25 µm); carrier gas Helium 
with a flow rate of 1 ml/min; GC temperature ramp: 140°C, initial 0.5 min, 10°C/min to 260°C, 
20°C/min to 290°C and held for 6 min. The MS was operated in the negative mode (NCI) with 
methane reagent at source pressure of 2.1 torr, ion source temperature at 200°C, quadrupole 
temperature at 100°C and interface temperature at 280°C. During an analysis, specific ions (m/z) 
for each analyte were monitored. Each analytical series included a reagent blank and controls for 
accuracy and precision. As quality control for accuracy served remaining material of the 27th ring 
test conducted by Professor J. Angerer (University of Erlangen, Germany), which was stored at 
20°C until used. The quality control for monitoring precision was prepared in the laboratory by 
spiking of pooled plasma of low-level exposed subjects with a defined quantity of the analytes. 
 
Results 
The two cohorts were quite similar with respect of age, number of previous births and smoking 
habits, table 1. 
 
Table 1: Characteristics of the two Faroese cohorts. 
Characteristic Pre-Advisory Cohort Post-Advisory Cohort 
Maternal age in years (mean±SD) 28.0 ± 5.8 29.6 ± 7.5 
Previous births (0/1/at least 2) in % 29.7/29.1/41.2 31.0/32.7/36.3 
Non-smoking during pregnancy in % 68.7 73.9 
 
Based on calculations of the 409 24-h recall interviews and the 732 food diary recordings the 
intake of pilot whale meat and blubber in average per day was 1.5 g and 0.6 g. The corresponding 
numbers forsea birds and ocean fish were 3.0 g and 40.2 g respectively.  
Organohalogen Compounds, Volumes 60-65, Dioxin 2003 Boston, MA
  
When the two groups of pregnant women are compared there is a significant reduction in the 
concentration of the congeners 153, 118 and 105. However, the reduction in total PCB is not 
significant, table 2 and figure 1. 
 
Table 2. The congeners with the highest concentrations in both cohorts and the sum of all 
congeners analysed. ng per gram lipid. 
Pre-Advisory cohort Post-Advisory cohort PCB 
Congener Min Max Mean St. Dev. Min Max Mean St. 
Dev 
153 10.0 3933.0 365.3 389.7 12.2 1756.8 264.7 248.0 
138 22.0 3529.0 259.0 315.8 13.3 1250.4 221.8 204.4 
180 9.0 1761.0 165.2 193.6 6.9 889.4 173.2 153.9 
118 5.0 1413.0 103.7 132.6 3.8 344.9 56.9 58.1 
Sum PCB* 69.0 13501.0 1296.5 1304.9 44.1 5430.6 1059.8 889.3 
*Calculated as sum of all congeners detected  
 
Figure 1: Average concentrations of main PCB congeners in the pre-advisory (1994) and 
post-advisory (2000) cohorts (in ng/g lipid). 
YEAR
20001994
M
ea
n
400
300
200
100
0
PCB-153
PCB-138
PCB-180
PCB-118
PCB-187
PCB-170
PCB-156
PCB-183
PCB-105
 
Organohalogen Compounds, Volumes 60-65, Dioxin 2003 Boston, MA
  
Discussion 
 
The recorded dietary intake of pilot whale meat and blubber is remarkably low when compared 
with the last dietary survey in 1981-82, where the average consumption of pilot whale meat 
among adult men and women was about 10-fold higher. This reduction is most likely to be a result 
of the recommendations issued by the health authorities to pregnant women to avoid contaminated 
seafood, such as pilot whale meat and blubber.  
 
The PCB concentrations are elevated at both examinations and therefore do not reflect the change 
in dietary habits. The dietary advisory regarding consumption of contaminated blubber from 
August 1998 therefore apparently has not yet led to a significant reduction of body burdens of 
PCBs in pregnant women in the Faroes.  
 
The results from the dietary survey also showed a very significant reduction in whale meat intake, 
and blood analysis shows a corresponding reduction in the mercury concentration levels. This 
observation suggests that the dietary change recorded is likely to be true. However, the PCB 
concentrations remain to be high and must be considered to be a continuing potential health 
problem in the Faroese community, especially in regard to prenatal exposure. The long half-life of 
these organochlorine compounds, as compared to methylmercury appears to an explain the 
sustained PCB concentration levels. 
 
 
Acknowledgements 
The work was supported by the European Commission (Environment and Climate Research 
Programme, EV 5V-CT940472), the U.S. National Institute of Environmental Health Sciences 
(NIEHS; ES06894), the Danish Medical Research Council, and the Danish Environmental 
Protections Agency as part of the environmental support program Dancea - Danish Cooperation 
for Environment in the Arctic. We thank Larry Needham and Wayman Turner at CDC for 
allowing us to use the serum PCB results from the pre-advisory cohort. The contents of this paper 
are solely the responsibility of the authors and do not represent the official views of the NIEHS, 
National Institutes of Health, or any other funding agency. 
 
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E., and Grandjean, P. (2000) Maternal seafood diet, methylmercury exposure, and neonatal 
neurological function. J. Pediatr. 136, 599. 
2. Grandjean, P., Bjerve, K.S., Weihe, P., and Steuerwald, U. (2001) Birth weight in a fishing 
community: significance of essential fatty acids and marine food contaminants. Int. J. 
Epidemiol. 30, 1272. 
3. Brock, J., Burse, V.W., Ashley, D. L., Najam, A.R., Green, V.E., Korver, M.P., et al. (1996) An 
improved analysis for chlorinated pesticides and polychlorinated biphenyls (PCB's) in human 
and bovine sera using solid-phase extraction. J. Anal. Toxicol. 20, 528. 
4. Vestergaard, T., and Zachariassen, P. (1987) Dietary survey 1981-82 [in Faroese.] Frodskaparrit 
33, 5. Hoppe, H.W. Organochlorine compounds in whole blood and plasma.  
5. Analyses of Hazardous Substances in Biological Materials, Volume 8. Chichester: Wiley-VCH, 
2003, pp. 187-220. 
Organohalogen Compounds, Volumes 60-65, Dioxin 2003 Boston, MA


Sustained high concentrations of PCBs in Faroese pregnant women despite dietary intervention

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