Johansen, P., Petersen, H.S., Asmund, G. & Riget, F.F. 2004. 2004. Technical Report from NERI no. 510, 32 pp.
English summary
Earlier studies have shown that the use of lead shot in the hunting of birds is an important source of human lead intake in Greenland. This study was initiated to investigate the relationship between the intake of birds and the lead concentration in human blood. We also studied if people in Nuuk during winter are particularly exposed to lead and a health risk, since the bird hunt takes place especially when the birds winter at South West Greenland.
50 people took part in the study. From September 2003 to June 2004 they regularly gave blood samples and recorded how many birds they ate. The study thus covers the period before, during and after the winter hunt.
Guillemots and eiders are the dominating species in the diet. They constitute 90 % of the number of bird meals recorded in the study period. The study shows that there is a clear relationship between the number of bird meals and the lead concentration in the blood of the participants. The lead concentration is higher when eating eiders than when eating guillemots. This finding is in accordance with earlier studies showing that meat from eiders in average contains about 8 times as much lead as guillemot meat. There is also a clear seasonal variation in the blood lead levels of the participants. The concentration is highest in mid winter when the bird consumption is at its highest. Thus this study confirms that the use of lead shot is of large importance as a lead source for humans in Greenland.
The blood lead concentration is low (mean 15 µg/l) among the participants reporting not eating birds. This is lower than in a study of Danes in the late 1990ies (mean 35 µg/l). Among the participants reporting to eat birds regularly, the blood lead concentration is significantly higher. Mean concentrations vary from 62 to 128 µg/l depending on the frequency of bird meals: the more bird meals, the higher resulting blood lead concentration. This clear relationship points to lead shot as the dominating lead source to people in Greenland.
American health authorities have defined 100 µg/l as a blood lead level of medical concern. In this study about 1/3 of the participants exceed this public health guideline in the middle of the bird-hunting season, whereas this is the case for only 1/6 before or after.
221 µg/l was the highest blood lead concentration measured in the study. This is 3-4 times lower than the level that could be expected to cause lead poisoning. However, in some cases the blood lead concentration in people from Greenland is high enough to impact the development of the central nervous system in fetuses and children.
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