I'r - Memorial University of Newfoundland

3.1 EXPERIMENTAL
3. METHODS
3.1.1 SAMPLECOUECTlONANDPREPAkAnON
Sample collection: A wide sampling program was conducted by the department of
Earth Sciences, Memorial University ofNewfoundland in collaboration with the
Department ofEnvironment, National Water Research Institute, Bur lington. Ontario. The
sample co llection was primarily perfonned by A. Stark., during the expeditionofRN
LIMNOS in swnmer 1994 (Stark. 1994). The beterogeneous nature ofsediments across
the lake necessitated that two different types ofsamp lers be used. Softer sediments were
obtained with a 30 x 12 em box corer which yielded sholt « 30 em) sediment cores.
However. in most cases the substrate consisted ofhard clays or glacial tills which
impeded deep penetration. A Ponar Grab with ajaw volume of82oo ml was employed at
these sites.
The sampling program was designed to provide the best possible coverage nfthe
lake. with more attention paid to the areas ofbigh potential sediment contamination (Fig.
2.2.3). A total of2] sites were sampled in the three major sedimentary basins oftbe lake
(Fig. 3. 1.1. Table 3.1.1). Comaminated sediment load introduced by fluvial systems is
known to be an important source ofsediment contamination in the receiving reservoirs .
As the Western Basin is characterized by the highest, fluvial input, the density of
sampling site s was increased here (9 sites). At least one site was sampled in the vicinity
of major industrial centers: stations 971 and 1012 at Detroit, 962 . 84 and 955 at
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