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MERC ER02-10
10
Active Chlorophyll-a
- Chlorophyll is used as ancillary data and as a general
presence/absence indicator of viable photosynthetic organisms.
T0 µg/l
TF µg/l
RG µg/l
Control
8.79 (0.48)
1.89 (0.06)
5.95 (3.11)
Treated
0.08 (0.01)
0.03 (0.01)
0.08 (0.09)
RG = after re-growth assay
MDL = 0.56 µg/l
Live Microbes
cfu = colony forming units
E. coli
T0
cfu/100ml
TF
cfu/100ml
Control
4.6 (1.82)
0 (0)
Treated
0 (0)
1 (1.41)
Enterococci
T0
MPN/100ml
TF
MPN/100ml
Control
8.78 (21.2)
49.34 (26.54)
Treated
2.02 (1.45)
107.4 (33.5)
MPN = most probable number estimates determined by the Idexx Enterolert kit. Note that this MPN is not a direct
cfu count and Enterolert MPN values are commonly found to be higher than the traditional membrane filtration
method used to estimate
Enterococci
abundances (G. Ditcher, Idexx).
V. cholerae –
No detectable culturable toxigenic
Vibrio cholerae
were detected in any
samples during any of the trials.
Heterotrophic
Bacteria
T0
cfu/1ml
TF
cfu/1ml
Control
146 (80)
503.33 (187.75)
Treated
0 (0)
10,520 (4,447.13)
Toxicity Summaries
Residual Chlorine
Analysis
- Levels of residual chlorine (or total residual oxidants -
TRO) were below the permissible discharge limit of 0.10 ppm in all TF treated samples. Values
ranged from 0.06 ppm to below the method detection limit (MDL) of 0.02 ppm.
Chronic Toxicity
- Results showed that ballast water discharge was not chronically toxic
to either mysids or sheepshead minnows. All samples, however, were chronically toxic to the
marine algal species
Isochrysis galbana
with a statistically significant inhibition in growth in
treated ballast discharge compared to controls.