Table T8. Level of seawater contamination expected in cores based on the concentration of PFT observed in sediment, and parallel bead counts, Holes 1230A, 1230B, and 1230C.
Core,
section
Sample details
ng PFT/
g sediment
Potential µL
seawater/
g sediment
Beads
counted
Beads/g
201-1230A-



1H-1 Center (slurry sect) 0.01 0.01 0 in 50 fields 0
1H-1 Outside (slurry sect) 0.48 0.48

1H-1 Center 0.03 0.03

1H-1 Outside 0.03 0.03

2H-2 Center (slurry sect) BD BD 0 in 50 fields 0
2H-2 Outside (slurry sect) 0.12 0.12

9H-6 Center 0.01 0.01

9H-6 Outside BD BD

13H-3 Center 0.22 0.22 6 in 50 fields 76
13H-3 Outside 1.42 1.42 73 in 50 fields 1813
15H-6 Center (slurry sect) 0.02 0.02 0 in 50 fields 0
15H-7 Center 0.01 0.01 0 in 50 fields 0
15H-7 Outside 0.34 0.34

21H-3 Center 0.03 0.03

21H-3 Outside 0.84 0.84

22H-2 Center 0.13 0.13

22H-2 Outside 2.55 2.55

30X-1 Center 0.35 0.35

30X-1 Outside 1.68 1.68

37X-1 Center 0.21 0.21

37X-1 Outside 5.91 5.91

38X-1 Center (dry portion) 0.03 0.03 0 in 50 fields 0
38X-1 Outside (dry portion) 1.33 1.33

38X-1 Center (HTEW, wet) 0.38 0.38 0 in 50 fields 0
38X-1 Outside (HTEW, wet) 2.04 2.04 1 in 100 fields (88.)
201-1230B-



12H-2 Center, near hydrate BD BD

12H-2 Outside, near hydrate 0.28 0.28

201-1230C-



1H-1 Center 0.72 0.72

1H-1 Outside 2.31 2.31

2H-1 Center BD BD

2H-1 Outside 0.65 0.65

2H-3 Center BD BD

2H-3 Outside 0.12 0.12

2H-4 Center BD BD

2H-4 Outside 0.34 0.34

2H-5 Center 0.01 0.01

2H-5 Outside 0.22 0.22

Notes: Detection limit = 0.01 µL seawater/g sediment, BD = below detection. The potential for microbial contamination is based on 5 x 108 cells/L surface seawater. This may be viewed as an upper limit for microbial contamination because it requires that the sediment be porous enough to allow all of the contaminating cells to travel with the PFT. In many cases, the level of contamination has been determined for both the outside of the core, where drill fluid is expected, and the middle of the core, where it may be clean. HTEW = thermophile enrichment whole-round core. Numbers in parentheses = not considered a significant indication of contamination (see text).