The Arctic at Risk:
A Circumpolar Atlas of Environmental Concerns
The Arctic at Risk:
Positions of sampling locations are presented in decimal degrees of latitude and longitude. Where available, locations were obtained from latitudes and longitudes reported by the author. Where no precise latitude and longitude values were given, values were assigned based on the location name and description provided. Data could not be included in the map when 1) no location was provided, 2) data was combined over a large area, and 3) the sampling site could not be located on a map based on the name of the site. Where separate studies with different data named the same location and did not specify latitude and longitude, the locations were offset slightly to show both data points on the map. Where data presented by an investigation were closely spaced in one study area, an average latitude and longitude were used to determine a representative location.
Location Name
The name of the location in the table includes as much detail as was reported by the author. When a general location was provided along with a more specific location, both were reported. Sometimes data from two locations in close proximity were reported together by the author. Occasionally two authors reported the same data, but each reported it using a different location name (e.g. body of water vs. land name). Care was taken to make sure that these values were not repeated in the data tables. Both locational names were reported in the tables.
Mean Concentrations
All values are reported as mean concentrations, unless otherwise indicated. If the mean value was not supplied by the author, weighted means were calculated by taking sample sizes into account. Pooled samples were assigned weights according to their given sample sizes. Where calculations of the mean were not possible from the data provided, medians, mid-ranges, or the given value (e.g., maximum value) were reported along with the necessary notation. Consult the original publication for additional information on the median, minimum, maximum, number of samples, etc.
Concentrations of contaminants in water are presented in ng/l. Unless otherwise noted, all water samples are from the surface, in water less than 15 meters deep. All tissue samples are reported in ug/g wet weight. Some of the data for heavy metals in marine mammals had to be converted from dry weight to wet weight. For liver tissue, a conversion factor assuming 72% water in liver tissue was used (Paul Becker, pers. comm., 1994), unless another value was supplied by the author.
Sample Year
This is the date that the sample was actually obtained. If the year was not given by the author, "NG" for "Not Given" was entered into this column. The date of sampling is important in cases where the environmental distribution of the contaminant has changed over time. For example, as noted above, DDT use has decreased substantially, resulting in a temporal trend toward declining DDT values in some parts of the Arctic ecosystem. All data used in this compilation were published since 1980, although some of the samples were obtained in the 1970's.
Reference and Original Reference
The "Reference" column cites the source that was used in making the map. The "Original Reference" column cites the study that first reported the analysis. Although it is preferable to consult the original reference, this was not always possible given the availability of source material and the limitations of this study. Where the reference consulted was also the first publication of the data, "NA"--for "Not Applicable"--was placed in the "Original Reference" column.
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