Spatial trends and historical profiles of organochlorine pesticides in Arctic lake sediments. Muir, D., C., G., Grift, N., P., Lockhart, W., L., Wilkinson, P., Billeck, B., N., & Brunskill, G., J. Science of the Total Environment, 160-161(C):447-457, 1995.
Spatial trends and historical profiles of organochlorine pesticides in Arctic lake sediments [pdf]Paper  abstract   bibtex   
Sediment cores were collected from eight remote lakes in Canada, along a mid-continental transect from 49°N to 82°N, with the objective of examining latitudinal and temporal differences in deposition of a wide range of persistent, semi-volatile, organochlorine (OC) pesticides such as DDT, dieldrin, hexachlorobenzene (HCB), hexachlorocyclohexane (HCH), and toxaphene. Samples were collected with a specially constructed ballot box corer (30 × 30 cm), or with large (10-cm) KB corers, from the deep basins of lakes at the Experimental Lakes Area (ELA) (49°30′N), Saqvacjuaq (63°39′N), Cornwallis Island (75°07′N), Axel Heiberg Island (79°N), and Northern Ellesmere Island (Lake Hazen; 82°N). Sediment slices were dated using 210 Pb and 137 Cs. Sediment extracts were analyzed by high-resolution GC-ECD with confirmation by GC-MS. Concentrations of total DDT ( ΣDDT) in surface sediments (0-1.3 cm depth) declined significantly with latitude from 9.7 ng/g (dry wt.) in ELA sediments to 0.10 ng/g in Lake Hazen. HCB levels showed a reverse trend; organic carbon normalized concentrations increased with latitude. Concentrations of other OC pesticides (total HCH, total chlordane, toxaphene, and dieldrin) were generally in the range of 0.1-3 ng/g, with the sites at 63°N and 75°N generally having the highest levels. The profiles of ΣDDT and total chlorobenzenes in all the mid-continental lakes showed maxima in slices dated from the late 1970s to the 1980s, which is about 5-10 years later than maxima reported for Lake Ontario. The results generally support several of the predictions of the cold condensation hypothesis. © 1995 Elsevier Science B.V. All rights reserved.

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