-------
TABLE 5-3
PARAMETER VALUES FOR HACKBERRY BAY CALCULATIONS
I
cr\
VALUES
PARAMETER BASE CASE RANGE
QQ 3.98 ft3/sec
RTRANS 1 ft
D 2 2-10
H 3 ft 2.5-3 ft
H2 3 ft 2.5-3 ft
V 0.035 ft/ 0.01-0.1
sec ft/sec
COMMENTS
Based on discharge data.
Conservatively small. Insignificant effect on
concentration distribution.
Two is conservative minimum.
Real mean depth. Varies with tidal height.
Realistic value considering shallow water depth.
Complete mixing assumed.
Based on net flow values.
V, 0.22 ft/sec 0.065-0.22 Consistent with tidal volumes.
ft/sec
U 0
U, 0 0.05
_L
XSHORE
E 0.1 ft2/sec 0.1-1.0
x ft2/sec
E 1.0 ft2/sec 0.1-1.0
" ftVsec
Ez 0
Hugo B. Fischer, "Longitudinal
Reasonable and conservative assumption in
absence of detailed current data.
Arbitrarily assumed to examine sensitivity
to rotational velocity component.
Account for boundaries by computing background
concentration with tidal flushing calculation.
Values of E /Hu* and E /HuA
ra
consistent with Fischer.
Complete mixing in water column assumed.
Dispersion and Turbulent Mixing in Open-Channel Flow,
Annual Review of Fluid Mechanics, Vol. V, ed . by Van Dyke (Palo Alto: Annual Reviews, Tnr
1973).
-------
A simplified current scheme was adopted in the calcula-
tions in which tidal and nontidal (i.e., freshwater) currents
were assumed to flow along the y-axis. Values for these
current velocity components were then estimated on the basis
of tidal volume information" using the somewhat involved
calculations described in Appendix E.
Values for the diffusion coefficients were estimated by
combining values of depth and current velocities with values
given by Fischer7 for the dimensionless quantity E/Hu*
where u^ is the friction velocity. This procedure is discussed
in more detail in Appendix E.
The concentration factor isopleths for the calculations
Hi through H9 enumerated in Table 5-2 are shown in Figures
5-7a through 5-7i, respectively, and plots of areas enclosed
by the isopleths versus dilution level are given in Figure
5-3 (above). The concentration factor isopleths are symmetric
with respect to the y axis.
5.4 Cook Inlet, Alaska
Table 5-4 presents a listing of the sets of input
parameters for which computer calculations were performed to
predict concentration factors for the Cook Inlet oilfied
area, and Table 5-5 gives for each parameter its base value,
range when varied, and comments about choice of values.
Of the seven known sources of brine discharge into Cook
Inlet waters (see Appendix D), two were selected for compu-
tations: the Trading Bay Production Facility with an average
daily discharge of 12,500 barrels brine (0.81 cubic feet per
second), and the Granite Point Production Facility with an
average discharge of 5,000 barrels brine per day (0.32 cubic
feet per second). Both of these are onshore facilities
which discharge brine into Cook Inlet close to the shore.
These facilities were selected on the grounds that the
impacted areas for these facilities would be considerably
larger than those corresponding to offshore platforms dis-
charging produced water into the much deeper waters of Cook
Inlet far from the shoreline.
Barrett, Cooperative Gulf of Mexico Estuarine Inventory
and Study, p. 57.
Hugo B. Fischer, "Longitudinal Dispersion and Turbulent
Mixing in Open-Channel Flow," Annual Review of Fluid Mechanics,
Vol. V, ed. by Van Dyke (Palo Alto: Annual Reviews Inc., 1973).
-68-
-------
TABLE 5-4
LISTING OF COMPUTER CALCULATIONS
PERFORMED
I
cr\
1
CALCULATION
Cl
C2
C3
C4
C5
(ft
0
0
0
0
0
Qn D
0
3/sec)
.81 2
.81 2
.81 2
.32 2
.32 2
RTRANS H
(ft)
1 8
1 8
1 8
1 8
1 8
H2
(ft)
8
8
8
8
8
Ax
0.005
0.005
0.005
0.005
0.005
FOR COOK INLET,
E
X
nx °xc
4/3 250
4/3 250
4/3 250
4/3 50
4/3 50
E
Y
(ft2/sec)
1,250
7,500
250
1,250
250
ALASKA
un
0
(ft/sec)
0
0
0
0
0
0
1
(ft/sec)
0
0
0
0
0
Vn V,
0 1
(ft/sec) (ft/sec) COMMENTS
0.014 n.a. Trading bay
0.014 n.a.
0.014 n.a.
production
facility .
Variation of
tidally averaged
diffusion
coefficient, E .
' Y
0.014 n.a.
0.014 n.a.
Granite point
production
facility.
Variation of E .
1 Y
-------
TABLE 5-5
PARAMETER VALUES FOR COOK INLET CALCULATIONS
o
I
PARAMETER
E
E
VALUES
BASE CASE
RANGE
COMMENTS
QQ 0.81, 0.32
RTRANS 1 )
D 2 f
H 8 )
H2 8[
V0 0.014
Based on discharge data.
Conservative minimum value.
Based on actual water depth.
Total mixing assumed.
Estimated from freshwater flow
data.
Un
0
u.
1
E ""
x
1
1 A
x
> nx
1 **
axc
0
0
0.005
4/3
250,
50 ft
Not input parameter. Maximum observed
value of 6.4 ft/sec used in computing
base case value of E .
Currents assumed to be
along shore only.
"4/3" diffusion law in direction
perpendicular to shoreline.
Eddy size bounded by distance to shore.
1,250 ft /sec 250-7,500 ft /sec Estimated by tidally averaged computation,
No vertical diffusion. Uniform mixing
assumed.
-------
The extremely fast tidal currents in Cook Inlet (see
Appendix A) with speeds up to 6.5 feet per second in the
region of the oil fields, and the consequently large tidal
excursions, result in a situation in which discharged con-
taminants tend to be sloshed back and forth over large
distances for a considerable length of time. The contaminants
are moved seaward only gradually by the relatively small
freshwater flow. In the computer model, concentrations are
calculated by summing over the contributions of a series of
contaminant "puffs" released at discrete time intervals. To
calculate a steady state concentration distribution, the
model must follow the course of the discharge puffs over the
period of time that the initial puff in the series remains
in the zone of interest. It follows that in the case of
Cook Inlet with its long flushing times, a lengthy computa-
tion is required if the model is to incorporate tidal currents
directly. In order to circumvent this problem, it was
decided to account for the effects of the tidal currents by
incorporating them into the alongshore diffusion coefficient,
Ey. The procedure for doing this is given in Appendix E
along the the associated calculation required to estimate
V_, the downstream freshwater flow velocity.
The concentration factor isopleths for the calculations
Cl through C5 enumerated in Table 5-4 are shown in Figures
5-8a through 5-8e respectively, and area vs. dilution plots
are given in Figure 5-4.
5.5 Near Offshore Gulf Waters
For Gulf of Mexico waters offshore from the barrier
islands and within the 3-mile limit, a site was selected in
Block 16 of the Grand Isle oilfield area offshore of Grand
Isle, Louisiana. Table 5-6 presents a listing of the"various
sets of input parameters for which calculations were per-
formed, and Table 5-7 gives base values, ranges when varied,
and comments about choice of values for each parameter.
The value of Q0 = 1 cubic foot per second used for the
base case (approximately 15,000 barrels produced water
discharged per day) is somewhat higher than the figure
obtained from the Louisiana Department of Conservation in
Houma, Louisiana, for 1975 produced water discharge in
Block 16 (approximately 9,000 barrels produced water discharged
per day). However, an average brine discharge of 15,000
barrels is known to occur in offshore waters (as can be seen
from USGS records for far offshore Gulf of Mexico brine
discharges), and since only one near offshore site was con-
sidered in this study it was decided that potential benefits
-71-
-------
100,000^
10,000-
i,ooo.o:
o
rH
JJ
fc.
<
<
100.0:
10.0-
1.0-
0.1
COOK INLET
WORST CASE
BEST
CASE
.01
,10 1.0
CONCENTRATION (%)
10.0
Figure 5-4. Area/concentration curves for Cook Inlet.
-72-
-------
TABLE 5-6
LISTING OF COMPUTER CALCULATIONS PERFORMED
CALCULATION
N1A
NIB
, NIC
U) N1D
1
N1E
N2A
N2B
N2C
Q0 D
(ft3/sec)
1
1
1
.5
1
1
1
1
25
10
25
25
25
5
5
5
FOR
RTRANS XSHORE
(ft) (ft)
20
20
20
20
20
20
20
20
15,000
15,000
15,000
15,000
15,000
2,500
2,500
2,500
THE
"l
(ft)
33
33
33
33
33
15
15
15
NEAR
112
(ft)
5.5
5.5
5.5
5.5
5.5
3.5
3.5
3.5
OFFSHORE GULF OF
Ax
.00524
.00524
.00524
.00524
.002
.00524
.00524
.002
Ex
n
X
4/3
4/3
4/3
4/3
4/3
4/3
4/3
4/3
°XC
(ft)
7,500
7,500
7,500
7,500
7,500
1,250
1,250
1,250
N
.00524
.00524
.00524
.00524
.002
.00524
.00524
.002
MEXICO SITE
Ey
ny V
(ft) i
4/3
4/3
4/3
4/3
4/3
4/3
4/3
4/3
U0
[ft/sec)
0
0
0
0
0
0
0
0
ul V0
(ft/sec) (ft/sec)
0
0
0
0
0
0
0
0
.37
.37
.18
.37
.37
.37
,18
.37
Vl
(ft/sec)
.25
.25
.12
.25
.25
.25
.12
.25
COMMENTS
Base Case:
XSHORE=3 miles
Variation of D
Variation of
Current Velocity
Variation of Qo
Variation of A-,
Ay
Base Case:
XSHORE=l/2 mile
Variation of
Current Velocity
Variation of Ax,
-------
TABLE 5-7
PARAMETER VALUES FOR NEAR OFFSHORE
GULF OF MEXICO CALCULATIONS
PARAMETER BASE CASE RANGE
Q0 (ft3/sec) 1 .5-1
D 25 5-25
XSHORE (ft) 15,000 2,500-15,000
H (ft) 33 15-33
H2 (ft) 5.5 3.5-5.5
A .00524 .002-. 00524
Ex -I «/3
a 7,500 1,250-7,500
xc
A .00524 .002-. 00524
Ey n* 4/3
o °°
yc
DO (ft/sec) 0
U, (ft/sec) 0
VQ (ft/sec)
Vj (ft/sec) ;
37 .18-. 37
25 .12-. 25
COMMENTS
Value of 1 chosen to given conservative estimate.
Value of D computed using EPA plume theory.3 Results not
sensitive to varying D by factor of 2.
15,000 is actual distance to shore. 2,500 used to test
sensitivity of results to variation of XSHORE.
Actual depth at site. 15 is approximate depth at XSHORE = 1/2 mile
H2 = l/6Hb
"4/3" diffusion law for horizontal diffusion in
ocean waters.0 Scale limited by distance
to shore. Value of .002 for A and A
x y
conservative estimate consistent with
published data. Results insensitive
to Ey.
Transverse (onshore) currents set equal to
zero. Conservative assumption.
Base Case values consistent with published
e f
studies. ' Lower values used to obtain more
conservative estimates.
Note: See references on following page.
-------
REFERENCES FOR TABLE 5-7
aM.A. Shirazi and L.R. Davis, Workshop of Thermal
Plume Prediction, Volume 1: Submerged Discharge, EPA-R2-
72-005a (Corvallis, Oregon: National Environmental
Research Center, U.S. Environmental Protection Agency,
August 1972).
G. Abraham, Jet Diffusion in Stagnant Ambient Fluid,
Delft Hydraulics Laboratory, Publication No. 29, 1963.
N. Brooks, "Diffusion of Sewage Effluent in an Ocean-
Current," in Proceedings of the First International Con-
ference on Waste Disposal in the'Marine Environment, Univer-
sity of California, Berkeley, July 22-25, 1959, ed. by
E.A. Pearson (Oxford: Pergamon Press, 1960).
R. Koh and L. Fan, Mathematical Models for the
Prediction of Temperature Distributions Resulting from
the Discharge of Heated Water into Large Bodies of Water,
for the U.S.Environmental Protection Agency, Water Quality
Office, Water Pollution Control Research Series Report
16130 DWO 10/70, October 1970.
0
P. Oetking et al., Currents on the Nearshore Continental
Shelf of South Central Louisiana,Report No.17,Offshore
Ecology Investigation, Gulf Universities Research Consortium,
May 1, 1974.
Louisiana Offshore Oil Port Environmental Baseline
Study, Volume II, Technical Appendices 1-5 (New Orleans:
LOOP, Inc.).
-75-
-------
of the EPA regulations could be more usefully estimated by
choosing a relatively high value for the rate of discharge.
A sensitivity run was made with the value of QQ equal to 0.5
cubic feet per second so that the impact associated with a
rate of discharge more closely approximating the actual
Block 16 discharge rate could be estimated. Several compu-
tations were made with a value of XSHORE (i.e., distance to
shore) of 0.5 miles instead of the actual distance of 3
miles offshore of Block 16. The results of these computations
can be used to indicate the predicted impacts of discharge
from platforms located one-half mile offshore.
Data on the depth of water, H, was obtained from the
NOAA National Ocean Survey 1:80,000 scale map of Barataria
Bay and approaches. The values for the thickness of the
initial mixing layer H2 were obtained from H by using the
relation H2 = H/6. The source for this relationship is
Abraham8 who gives a range for H2 of from H/12 to H/6. The
larger value of H2 (i.e., H2 = H/6) was used in the computa-
tions since vertical diffusion was not explicitly incorporated
into the computations, and the assumption of a thick mixing
layer without vertical diffusion is roughly equivalent to
assuming a thin initial mixing layer with vertical diffusion.
The values of D were computed on the basis of values of
H, H2, and QQ using charts given in the EPA Workbook of
Thermal Plume Prediction^ (see Appendix E). Diffusion
coefficients were computed using the "4/3" diffusion law
discussed in Appendix B. The base case value of Ax = Ay =
0.00524 is taken from Brooks.1° The sensitivity test value
of Ax = Ay = 0.002 is consistent with a range of 0.001 to
0.06 reported by Koh and Fan.H
g
G. Abraham, Jet Diffusion in Stagnant Ambient Fluid,
Delft Hydraulics Laboratory Publication No. 29, 1963.
9
M.A. Shirazi and L.R. Davis, Workbook of Thermal Plume
Prediction, Volume 1: Submerged Discharge, EPA-R2-72-005a
(Corvallis, Oregon: National Environmental Research Center,
U.S. Environmental Protection Agency, August 1972).
N. Brooks, "Diffusion of Sewage Effluent in an Ocean-
Current," in Proceedings of the First International Conference
on Waste Disposal in the Marine Environment, University of
California, Berkeley, July 1959, ed. by E.A. Pearson (Oxford:
Pergamon Press, 1960).
R. Koh and L. Fan, Mathematical Models for the Prediction
of Temperature Distributions Resulting from the Discharge of
Heated Water into Large Bodies of Water, for the U.S. Environ-
mental Protection Agency, Water Quality Office, Water Pollution
Control Research Series Report 16130 DWO 10/70, October 1970.
-76-
-------
The base case drift current velocity of 0.37 feet per
second was obtained from the GURC study. ^-2 The tidal current
velocity value of 0.25 feet per second is in accord with
studies of the tidal current made for the proposed Louisiana
Offshore Oil Port (LOOP).13 The assumption that all currents
are in the alongshore direction (UQ=U]_=0) is a conservative
one since the tidal current component then transports the
discharge back and forth in the same line.
The concentration factor isopleths for the calculations
NlA through N2C listed in Table 5-6 are shown in Figures 5-9a
through 5-9h, respectively, and plots of the areas enclosed
by the isopleths are given in Figure 5-5.
5. 6 Far Offshore Gulf of Mexico Waters
For Gulf of Mexico waters beyond the 3-mile limit, a
site was selected in Block 108 of the Ship Shoal oilfield
area. Block 108 is located approximately 27 miles offshore
with a depth of water of only 20 feet.14 Table 5-8 presents
a list of the various sets of input parameters for which
calculations were performed to obtain concentration factors
for far offshore Gulf waters, and Table 5-9 gives for each
input parameter its base case value, other values used, and
comments about choice of these values.
As in the case of the near offshore calculations, a
value of QQ = one cubic foot per second (15,000 barrels per
day) was used. This value is reasonable considering that
the average 1975 produced water discharge rates of Chevron
platforms S-93 and S-94 in Block 108 were 9,000 and 12,000
barrels per day, respectively. Values of the mixing layer
thickness, H2, the initial dilution, D, and the diffusion
coefficients were obtained as described in Section 5.5.
Estimates of the current magnitudes were obtained from the
P. Oetking et al., Currents on the Nearshore Continental
Shelf of South Central Louisiana, Report No. 7, Offshore
Ecology Investigation,Gulf Universities Research Consortium,
May 1, 1974.
13Louisiana Offshore Oil Port Environmental Baseline Study
Volume II, Technical Appendices 1-5 (New Orleans: LOOP, Inc.).
"^Transcontinental Gas Pipe Line Corporation iMap of South
Louisiana and Louisiana Continental Shelf Showing Natural Gas
Pipe Lines, Transcontinental Gas Pipeline Corporation, 1974.
-77-
-------
1000.0
100.0:
(N
<
<
lo.o:
o.oi
GRAND ISLE
0.1 1.0
CONCENTRATION (%)
10.0
Figure 5-5. Area/concentration curve for Grand Isle
site in near offshore Gulf of Mexico.
-78-
-------
TABLE 5-8
LISTING OF COMPUTER CALCULATIONS PERFORMED
FOR THE FAR OFFSHORE GULF
OF MEXICO SITE
"° " "'" 'Tf'tP ('ft) (ft) Ax
FX 1 11 20 » 20 3.3 .00524
F0 1 11 20 «» 20 3.3 .00524
1 2
— 1
10 F, 1 11 20 20 3.3 .002
i J
F4 1 5 20 <» 20 3.3 .00524
E
X
nx
4/3
4/3
4/3
4/3
E
y
a A n n
xc y y °yc
.00524 4/3
°° .00524 4/3
.002 4/3
» .00524 4/1
U0 Ul V0 Vl COMMENTS
0 0 . 37 . 37 Base Case
0 0 .18 .18 Current
Sensitivity
0 0 .37 .37 Diffusion
Coefficient
Sensitivity
0 0 .37 .37 Initial
Dilution
Sensitivity
-------
TABLE 5-9
PARAMETER VALUES FOR FAR OFFSHORE
GULF OF MEXICO CALCULATIONS
I
oo
o
I
PARAMETER BASE CASE RANGE COMMENTS
Q (ft /sec) 1 Value of 1 consistent with discharge data.
D 11 5-11 Computed using EPA plume theory. a
H 20 Actual depth of water in block IDS, ship shoal oilfield area.
H2 3.3 H2 = H/6b.
AX, A .00524 .002
Ex'Ey "V ny 4/3
o o
xc, yc
U0 °
u1 o
VQ .37 .18-. 37
Vx .37 .18-. 37
"4/3" diffusion law for horizontal diffusion
in ocean waters,0 Value of .002 for AX, A
conservative estimate consistent with published data.
Transverse currents set equal to zero.
Conservative assumption.
Base case values consistent with published study. Lower
values used to obtain more conservative estimate.
Note: References a-e are identical to references a-e in Table 5-7.
-------
GURC Study report. The conservative assumption was made
that both drift and tidal currents flow along the same axis.
The concentration factor isopleths for the calculations
Fl through F4 listed in Table 5-8 are shown in Figures
5-10a through 5-10d, respectively, and plots of the areas
enclosed by these isopleths are given in Figure 5-6.
Oetking et al., Currents on Nearshore Continental
Shelf of South Central Louisiana.
Q 1
"~ O -1.
-------
XJCO.CH
tooo.
o
.-I
<
w
«
<
W.O-
FAR OFFSHORE
GULF OF MEXICO
,\ WORST
F2.F4
001
' r
0.1
1.0
CONCENTRATION (%)
10.0
Figure 5-6. Area/concentration curves for far offshore
Gulf of Mexico site.
-82-
-------
5000 -
4000 _
-4000
800
FEET
j I _L
1000 1200
1400
-5000 _
Figure 5-1 a.
HI: Base case.
Percent dilution isopleths, Hackberry Bay, La
-83-
-------
• 5000 -'
Figure 5-7b. Percent dilution isopleths, Hackberry Bay, La
H2: Diffusion coefficient sensitivity, E =E =1.0
-84-
-------
5000 -
4500 ~
UJ-LL
1 I !_
800
FEET
j j
iOOO
J
1200
-I-.-
140u
X
-4500 -
-500C-
Figure 5-7c. Percent diffusion isopleths, Hackberry Bay, La.
H3: Diffusion coefficient sensitivity, E =E =1.0
-85-
-------
5000 -
4000 -
-4CQO
X
-5000 -
Figure 5-7d. Percent dilution isopleths, Hackberry Bay, La,
H4: Initial dilution sensitivity, D=5,(E =1.0)
X
-86-
-------
5000 -
4000
3000 -
2000 -
1000 r
-3.000 K
-2000 -
-3000
-4000
-5000 -
___ -*r
Figure 5-7e. Percent dilution isopleths, Hackberry Bay, La,
H5: Initial dilution sensitivity, D=10,(E =1.0)
X
-87-
-------
5000 -
4000 -
-3000
-4000
X
Figure 5-7f. Percent dilution isopleths, Hackberry Bay, La
H6: Tidal velocity sensitivity, V =0.065, (E =1.0)
J_ X
-88-
-------
En
K
-1000 -
-1500 -
-3000
-3SOO -
-OOO -
-4500 -
-5000 -
1000
1200
1400
X
Figure 5-7g. Percent dilution isopleths Hackberry Bay, La.
H7: Freshwater current velocity sensitivity, V =0.1 (E =1.0)
-09-
-------
5000 -
4500 '
4000 -
3500 -
3000 -
2500 -
2000 -
1500
1000 -
500
K)
w
fa
-500 -
-1000 -
-1500 -
-2000 -
-2500 -
-3000 -
-3500 -
-«000 -
-4500-
-5000-
X
Figure 5-7h. Percent dilution isopleths, Hackberry Bay, La
H8: Freshwater current velocity sensitivity, V =0.01 (E =1.0)
O X
-90-
-------
-4500
-5000
Figure 5-7i. Percent dilution isopleths, Hackberry Bay, La
H9: Rotational tidal current sensitivity, U =0.05 (E =1.0)
1 X-
-91-
-------
SHOPZI.INE
200 310 41)0 MO 300 700 SOO 900 1000
-10,001
Figure 5-8a. Percent dilution isopleths, Trading Bay
Facility, Cook Inlet, Alaska.
Cl: Base Case, E =1250.
-92-
-------
S'-iORELINE-J
-5,000
-6.COO
-7,000
-8,000
-9.000
IC.oCO
200 300 400 5nO 600 700 800 900 1000
FEET
Figure 5-8b. Percent dilution isopleths, Trading Bay
Facility, Cook Inlet, Alaska.
C2: Diffusion coefficient sensitivity, E =7500.
Y
-93-
-------
•b.
I
6,000
5,000
4,oon
3,000
2.000
-2.000
.05
0 200 300 40C SOO 600/ 700 800 900 1000 1100 1200 1300 1400 1500 1600 1/00 1800 1900 2000
-10.000
Figure 5-8c. Percent dilution isopleths,Trading Bay Facility,
Alaska.
C3: Diffusion coefficient sensitivity, E =250.
-------
SHC-FELi.TE
-4,
-5,
-e.ioo
-7,
-8,i
-9,
00
0?
00
oo •
00
00
20G 30
40C 500 600 700 SOJ 900 1000
FEET
-10.0301-
Figure 5-8d. Percent dilution isopleths, Granite
Point Facility, Cook Inlet, Alaska.
C4: Base Case, E =1250.
-95-
-------
.05
SI! jrELIKE
200 300 I 40C 500
FEET
300 900 1000
-10,300
Figure 5-8e. Percent dilution isopleths, Granite
Point Facility, Cook Inlet, Alaska.
C5: Diffusion coefficient sensitivity,E =250.
-96-
-------
Y
10,000-
9000
8000
7000
6000
5000
W 4000
W
3000-
2000
1000
1,
2.
0
-1000
100 200 300 400 500 600 700 800 900 1000
FEET
X
Figure 5-9a. Near offshore dilution percentage isopleths.
N1A: Base case, XSHORE=3 miles.
-------
00
I
Y
10,000-
9000
8000
7000
6000
5000
EH
W 4000
W
3000
2000
1000
1.
2.
0
-1000
.5
100 200 300 400 .>00 600
FEET
700 800 900 1000
X
Figure 5-9b. Near offshore dilution percentage isopleths.
NIB: Dilution sensitivity, D=10 (XSHORE=3 miles)
-------
W
w
c-4
10,000-
9000
8000
7000
6000
5000
4000
3000
2000
1000
1.
2t
-1000-
—i 1 1 1 1 - • i—
100 200 300 400 500 600
FEET
700
—1 1 1
800 900 1000
X
Figure 5-9c. Near offshore dilution percentage isopleths.
NIC: Current velocity sensitivity, V =.18, V = .12 (XSHORE=3 miles)
-------
o
o
I
EH
W
W
Pn
10,000-
9000
8000
7000
6000
5000
4000
3000
2000
1000
1.
0
-1000-
.05
100 200 300 400
500 600
FEET
700 800 900 1000
X
Figure 5-9d. Near offshore dilution percentage isolpleths
N1D: Discharge rate sensitivity, Q =.05 (XSHORE=3 miles)
-------
I
M
O
M
I
10,000
9000
0000
7000
6000
5000
W
W 4000
3000
2000
1.
1000
2.
-1000
.5
.05
100 200 300 400 500 600 700 800 900 1000
FEET
X
Figure 5-9e. Near offshore dilution percentage isopleths.
N1E: Diffusion coefficient sensitivity, A =A =0.002 (XSHORE-3 miles)
-------
I
M
O
I
W
Cn
10,000-
9000
8000
7000
6000
5000
4000
3000
2000
1000
2.
-1000
100 200 300 400
500 600
FEET
700 800 900 1COO
X
Figure 5-9f. Near offshore dilution percentage isopleths
N2A: Base case, XSHORE=% mile.
-------
10,000-
9000
t
M
O
I
W
W
8000
7000
6000
5000
4000
-1000
500 600
FEET
700 800 900 1000
X
Figure 5-9g. Near offshore dilution percentage isopleths.
N2B: Current velocity sensitivity, V =.18, V =.12 (XSHORE=Jj mile)
-------
o
£*
Pn
10,000-
9000
8000
7000
6000
5000
4000
3000
1.
2000
2.
1000
-1000-J
.05
100 200 300 400 500 600 700 800 900 1000
FEET
Figure 5-9h. Near offshore dilution percentage isopleths.
N2C: Diffusion coefficient sensitivity, A =A =0.002 (XSEORE=h rcile)
-------
o
Ul
I
W
W
10,000-
9000
8000
7000
6000
5000
4000
3000
2000
1000
-1000
100 200 300 400 WO 600 700 600 900 1000
FEET
X
Figure 5-10a,
Fl: Base case.
Far offshore dilution percentage isopleths
-------
10,000
9000
8000
\
7000
I
H-1
O
I
EH
W
W
6000
5000
4000
3000
2000
WOO
-1000
200 300 400 500 600 700 800 900 1000
FEET
X
Figure 5-10b. Far offshore dilution percentage isopleths.
F2: Current velocity sensitivity, V =V =0.18.
-------
I
M
O
I
10,000
9000
8000
7000
6000
5000
W 4000
W
3000
2000
1000
.05
-1000
100 200 300 400 500 600 700 800 900 1000
FEET
X
Figure 5-10c. Far offshore dilution percentage isopleths,
F3: Diffusion coefficient sensitivity, A =A =0.002.
-------
o
CO
I
10,000-
9000
8000
7000
6000
5000
W
W
200 300 400
-1000
500 600
FEET
700 800 900 1000
X
Figure 5-10d. Far offshore dilution percentage isopleths,
F4: Initial dilution sensitivity,D=5.
-------
CHAPTER SIX
METHODOLOGY FOR IMPACT ASSESSMENT
6.1 Introduction
This chapter is concerned with the data and analytical
methods which were used for predicting the toxic impacts
which would result from the altered toxicant and salinity
distributions in the waters surrounding an offshore oil
drilling site as a result of brine discharges. Two classes
of brine-related impacts are considered here: toxic effects,
including direct mortality and a variety of sublethal effects
on resident organisms; and potential human health effects
resulting from the consumption of oysters or other organisms
which can accumulate in their body tissues high levels of
toxic metals and hydrocarbons. Because of the highly
variable and nonsystematic nature of the available data on
the toxic effects of pollutants, the analysis described here
is necessarily only semi-quantitative, and based on simpli-
fying assumptions derived from general toxicological consi-
derations and from recent field studies of biological
communities in the vicinity of offshore drilling sites in
Louisiana and Texas. It is believed that the approximations
which are introduced have at least order-of-magnitude validity;
and the results, which are described in a subsequent chapter
of the report, should be considered in that light.
The material in this chapter is of two types. The
first consists of toxicity data directly used in the impacts
analysis of the next chapter, and the second deals with a
variety of issues (e.g., synergisms, adaptation responses,
etc.) which although not used directly in the analysis due
to the lack of quantitative data, are nonetheless secondary
considerations which should be kept in mind in interpreting
the conclusions reached in this report.
6.2 Methodology
The assessment of impacts, outlined in Figure 6-1,
consists basically of delineating a "zone of impact" outside
of which only insignificant impacts would be predicted on
ecological communities and on contaminant levels in human
food organisms. Determining the area of this zone of impact
involves three steps:
-109-
-------
Criteria
LC50 Data
Sublethal Effects
Data
Estimation of "Safe"
Concentrations
Levels in Brines
Calculation of Necessary
Dilution Factors
Determine Dominant
(Longest Range)
Effect
Data on Human
Health Effects
Bioaccumulation
Data (Hg,BaP)
Dispersion Model
Outputs
Determine Impacted
Areas(Best,Worst Cases)
Figure 6-1. Outline of the analysis.
-110-
-------
1. For a particular class of impact, a set of "safe"
levels must be defined for each toxic contaminant
in oilfield brines.
2. The safe levels of each constituent must then be
compared with the levels actually found in oil-
field brines to produce a Necessary Dilution
Factor (NDF) for each constituent; i.e., the
dilution necessary to bring that constituent down
to a "safe" level.
3. The dispersion model output described in the
previous chapter can then be used to determine the
area around the production platform in which the
dilution of each constituent is less than or equal
to its NDF. The maximum area for any of these
constituents will then be used as an estimate of
total impacted area.
Similar analyses can be done for specific classes of
effects which are known to be associated with the pollutants
found in oilfield brines. For example, the band between two
adjacent isopleths produced by the dispersion model repre-
sents a region of predicted pollutant concentration in the
range x to x + Ax, for some particular x, and the tables of
effects given later in this chapter can then be consulted to
see if any significant effects have been noted on organisms
in that range of concentrations. Thus, the type of effect,
and in some cases, the absolute magnitude of the effect (in
terms of number of organisms affected) can be estimated for
each band. This information is complemented by the calcu-
lations of the areas of impacted zones, which provide a
useful summary statistic for the whole site.
Three separate estimates of "safe" (no effects) concen-
trations are made for each brine constituent based upon the
toxicological data presented later in this chapter. The
first is based on the EPA marine water quality criterion for
each constituent (see Table 6-1); a second is based on the
minimum concentration at which any adverse effect has been
noted in the literature; and a third is based on the use of
an application factor of 0.01 in conjunction with 96 hr LC50
data. (The use of an "application factor" of 0.01 together
with 96 hr LC50 data in predicting safe levels is supported
-111-
-------
TABLE 6-1
EPA WATER QUALITY CRITERIA FOR BRINE CONSTITUENTS
MAXIMUM RECOMMENDED
SUBSTANCE LEVEL3 APPLICATION FACTOR3
(mg/1)
Arsenic 0.05b 0.01 x 96 hr LC50b
Cadmium 0.005° 0.01 x 96 hr LC50b
Chromium 0.1 (0.01 in 0.01 x 96 hr LC50
oyster-producing
areas) *-*
Copper 0.05b 0.1 x 96 hr LC50°
Cyanide 0.005° 0.1 x 96 hr I,C50b
Lead 0.05b 0.01 x 96 hr LC5QC
Mercury 0.0001C
Nickel O.lb 0.01 x 96 hr LC50°
Oil & Grease -- 0.01 x 96 hr LC50C
Silver 0.005b 0.01 x 96 hr LC50°
Zinc O.lb 0.01 x 96 hr LC50b
aCriterion is lower of the numbers in these two columns,
Committee on Water Quality Criteria, Water Quality
Criteria 1972, National Academy of Sciences and National
Academy of Engineering, 1972.
°U.S. Environmental Protection Agency, Quality Criteria
for Water, 1976, Washington, D.C.
-112-
-------
both in recent EPA water quality criteria documents and in
the technical literature.2 it is believed to represent a
margin of safety adequate to protect marine communities from
significant acute and chronic deleterious effects. The use
of application factors in interpreting lethal concentration
data is discussed later in this chapter.)
Accurate numerical estimates of the degree of risk
associated with the human consumption of fish or shellfish
which have accumulated quantities of trace metals or hydro-
carbons are, of course, impossible to obtain, so the follow-
ing highly qualitative approach is adopted. The analysis
will concentrate on a two components of oilfield brines
which are known to be bioaccumulated and to pose a signifi-
cant human health risk: benz[a]pyrene and mercury. For
benzpyrene, an important hydrocarbon carcinogen in crude
oil, extrapolations from concentrations in water to concen-
trations in sessile food organisms such as shellfish will be
estimated based on available data on the bioaccumulation of
aromatic hydrocarbons. Although reliable dose response data
for this chemical are not available, the estimated concentra-
tion in fish will be considered unacceptable if it exceeds
the background level of benzpyrene exposure in other food
sources, as estimated in previous studies. Mercury bio-
accumulation will be estimated from available data on
mercury accumulation rates for various organisms, and the
final levels in organisms will be considered unacceptable if
they exceed the 0.5 ppm standard currently prevailing in the
United States and Canada. Each site can then be charac-
terized by the area of its "unacceptable" or "unsafe" region.
Two important assumptions of the impact analysis are:
1. That there is no significant toxicity modification
due to complexation of metal ions, oxidation or
reduction, microbial degradation of hydrocarbons,
and other environmental interactions (in other
words, it is assumed that these effects are small
For example: "The maximum acceptable concentration of
mercury in marine or estuarine waters is 1/100 (0.01) of the
96 hr LC50 value determined using the receiving water in
question and the most important sensitive species in the
locality as the test organism." U.S. Environmental Protection
Agency, Water Quality Criteria, 1973, p. 275. Similar criteria
are set for other metals.
2
See the data reviewed in J.B. Sprague, "Measurement of
Pollutant Toxicity to Fish--III. Sublethal Effects and
'Safe1 Concentration," Water Research 5 (1971): 257.
-113-
-------
in magnitude compared with concentration effects
which depend only on the rate of dilution of the
brine).
2. That the effects of the pollutants are purely
additive, and do not depend in a synergistic or
antagonistic fashion on the levels of other
pollutants. In general, this second assumption is
not valid, since synergisms have been noted for
trace metals, but it has been shown to hold for at
least some pollutants at low concentrations (on .,
the order of only a few tenths of their LC50's).
These assumptions are made necessary by the absence of
quantitative data on the extent to which environmental
interactions or synergisms with other pollutants will effect
toxicity at a particular site.
6.3 Toxicity Data
6.3.1 Introduction
Tables 6-2 through 6-12 summarize currently available
data on the toxicity of crude oil, phenol, and trace metals
(silver, copper, mercury, cadmium, chromium, zinc, nickel,
arsenic, and lead) to organisms in marine and estuarine
environments. (See Figure 6-2 for an explanation of the
format of these tables.) In addition, supplementary data
are presented in Table 6-13 relating to the toxicity of
specific crude oil fractions and components. This section
will deal briefly with some of the factors which must be
taken into account in interpreting and applying the data
contained in these tables.
See, for example, J.B. Sprague and Ramsay, "Lethal
Levels of Mixed Copper-Zinc Solutions for Juvenile Salmon,"
Journal of the Fisheries Research Board of Canada 22(2) (1965):
425-432, who found an additive interaction between copper and
zinc for the juvenile Atlantic salmon in the range of one toxic
unit, and a superadditive interaction only at much higher levels.
-114-
-------
Typical Data Point: 0.32 ppm - Incipient lethal level of copper for
juvenile Atlantic salmon (J.B. Sprague
and B.A. Ramsay, Journal of the Fisheries
Research Board of Canada 22/2) (1965) :
425-432)
is entered in Table 6-3 as follows:
CONCENTRATION (mg/1)*
LOCATION REFERENCE
1.000
•1 mg/1 - 1 ppm
Tables use the approximation 1 ppm = 1 rag/1. Location code indicates whether tested
species is found in Alaska (A) or Louisiana (L) waters. Superscript s indicates that test
species is found in location; superscript g indicates that other species of the same genus
as the test species are found in the location.
Figure 6-2. Explanation of toxicity tables.
-------
TABLE 6-2
TOXICITY TABLE - COPPER
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1 ,000
92 hr. LC50 for Artemia
centration which produces Sot reduction within 1 h
hronlc exposure of flounder Pseudopleuronectes at thl
hr. LC50 for Haterslporia
he. ICiO (or Splrot,
11
LCD r
Caused 11.3* mortality in 2* nra. in HUgcr
Reduced On Consumption 591 in mud snail Haasariur obsolet
6 h
Causes greening of oysters within 3 wkt
o.i ---
o.oi "irrr::1
Raymont and Shields (1962)
Wiiely And BUck 1196?)
Jackim !191Di
jackim U9'0}
Jackim (1970)
Jackim (1970)
Payment and Shields (1962)
Eisler and Gardner (1973)
Bryan and Humnverstone (1971}
Hiaely and Slick (1967)
Pyofinch and Mott
Pyefinch and Mott
6)
Bryan and Hummeratone (1*71
Rayront and Shields (1961)
ott
Pyefinch and Mott
Rjymont and Shields (196:)
laymont and Shields (1962)
Calabreae (1973)
Raymont and Shield* [19631
Stephenaon and Taylor (1975)
Stephenson and Taylor (Z975J
*1 mg/1 = 1 ppm
-------
TABLE 6-2 (CONT.)
TOXICITY TABLE - COPPER
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1,000
72 hr. LC100 for Acmaea and Haliotla
0.01
0.001
EPA (1973)
EPA (1973)
Calabrese (1973)
EPA (1973)
Sprague (1964)
Bornos and Stanbory 1191
JUiymont «nd Shields (I9fi
et al. (19^1
*1 mg/1 = 1 ppm
-------
TABLE 6-3
TOXICITY TABLE - ZINC
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
100
0.001
0.0001
0.00001
dulu
2 hr, LC50 for Hat
Interpolated 24 hr LC50 for Atlantic salmon amolta
o.oi - —-\~-
Eifller and Gardner (1973)
Wisely and Bliek (1967)
Herbert and Wakeford (196*)
EPA (1973)
7)
Wisely and Blick 11967)
Sprague (1964)
Calabrese (1973)
Venlilla (1973}
EPA (1973)
*1 mg/1 = 1 ppm
-------
TABLE 6-4
TOXICITY TABLE - CHROMIUM
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1,000
100
10
1 •-
0.1
Raymont and Shields (1962)
Calabrase (197])
Raymont and Shields (1962)
Raymont and Shields (1962)
Raymont and Shields (19C2)
EPA (1973)
*i mg/1 « 1 ppm
-------
TABLE 6-5
TOXICITY TABLE - LEAD
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1 ,000
100
10 -
1 -
0.1
0.01
JacXLm (1970)
- concentration
in seawater
EPA (1973)
EPA (1973)
*1 mg/1 = 1 ppm
-------
TABLE 6-6
TOXICITY TABLE - MERCURY
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1000.0
2.5 hr. LC50 for Aytemia
population)
.2 hr. LCSQ for Mytllus
CH3HgCl)
24 hr. exposure produced B0% mortality in Vustralorbia
use.1 104 24 hr. mortality in Hitocy
2,5 hr. LC50 for Elminius
96 hr exposure (Fundulus) caused 19,1% reluctio
bovo, 31.94 reduction in xanthine oxLdase level
6 hr. TLm for Fundulua
gill filaments witnin a 28 day expounre
4 hr. exposure caused 53* reduction in efficiency of
Caustd 100% reduction ir settlement by ciprida of
barnacle Dal anna balanoidoa (19 day exposure)
hr. exposure caused 22 2% reduction in efficiency
Gambuaia in escaping predation by Hicropterus
Wisely and Ulick (1967)
Barnes and StanUuiy (1'J48)
Barnes and Stanbury (1948)
Hiaely and Dlick (1967)
LPA (1973)
Barnes and Stanbury (1948)
Pyefinch and Mott
Jackim (1970)
Jacnim (1970)
Jacttim (1970)
Jackim (1970)
Pyefinch and Kott
Darnes and Stanbury (1948)
Wisely and Dlick (19671
Kania and O'Hara (1974}
Wisely and Blick (1967)
Pyefinch and Mott
Kama and O'Hara (1974)
Kama and O'Hara (1974)
C^labres-e (19131
Calabrese (1973)
Ventilla (1973)
EPA U9131
EPA (1973)
Calabrese (1973)
0.001
*1 mg/1 = 1 ppm
-------
TABLE 6-7
SILVER
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
10
0.1
0.01
0.001
Approximately double O. consumption in H.'tllua
:au< ed approximately 141 increase in 0., >:onBumption
0.0001
lowed development and induced abnormal iltitei in
mb.
EPA (1973)
Maclnnen an
Jackim (1970)
Jackim (1970)
Jackim (1970)
Jackim (1970)
Calabrete (1973)
Calabrese (1973)
EPA (1973)
Calabtesa (1973)
EPA (1373)
EPA (1973)
*1 mg/1 = 1 ppm
-------
TABLE 6-!
CADMIUM
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1,000
10
0.1
0.01
0.001
,48 hr. TL25 blue mussel, Hytilua edulia
/96 hr. TL25 blue mussel, Hytilua edulia A9
hr. TLSO blue mussel, Hytilua edulis A9
-24 hr. killifish. Fundulua majalls L9
. 48 hr, TL25 soft shell clam. My a arenajrla.
-24 hr, TL50 Atlantic oyster drill, Urosalpinx cinerea L9
-24 hr, TL50 killiiish, Fundulus majalls L9
-48 hr. TLSO mud snail, N a s s ar i u s gb_s_p_letu_s L9
24 hr, TL75 Atlantic oyster drill, Urosalplnx ein_ere_a L9
46 hr, TL25 green crab, Carclous maenus
24 hr.
48 hr, TL75 blue mussel, Mytilus edulis A9
24 hr, TL75 klllifish, Fundulus majalis L9
48 hr. TL25 killifish, Fundulus maj^ljlj L9
96 hr. TL25 shecpshead minnow, Cyprinodon, va r iggatua A5
X24 hr. TL75 sheepshead minnow, Cyprinodon variegatus A*
hr, TLSO klllifish, Funduluj ma]alis L
'168 hr. TL25 mummichog, Fundulua heterocUtus L9
hr. TLSO mummichog, Fund_ulus heterOcl^ttua L9
24 hr. TL25 grass shrimp, Palacmqnetcs vulgarIs L*
L96 hr. TLSO ahr>epaheaa minnow, Cyprinodon va r i .egatua L*
20 hrs.
L 24
I hr. TL25 sandworm, Ne^eJ^ yirens
: hr, TL7S shecpshc.sJ -"i' now, Cyprinodon varlegatua
Veduction in acid phosplmtase levels; 10.61 reduction in
anthinc oxidase levels, and 17 31 reduction in caLalata
ilevels in surviving Fundulus
V96 hr. TL50 blua musael, Mytilus edulia
Eialor (1971)
Elaler (1971)
Eisler (1571)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Elaler (1971!
Clsler (1971)
Eisler (1971)
Eisler (197U
Eisler (1971)
Eisler (1971)
Eisler (1971)
Elaler (1971)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Eialer (1971)
Eisler (1971)
Eisler [1971)
Elaler (1971)
Elsler (1971)
Eisler 11971)
Eisler (1971)
Eisler (1971)
Eisler (1371)
Elsler 11971)
Eialer 11971)
Eisler (1971)
Gardner and Yevich (1970)
Eialer (1971)
Eisler (1971)
Eialer (1971)
Eisler (1971)
Eisler (1971)
Eialer (1971)
Eislej (1971)
Eisler (1971)
Eialer (1971)
Eisler (1971)
Eialer {19711
Eisler 11971)
Eisler 11971)
Eisler (1971)
EiBlar (1971)
Eisler (1971)
Eial^r (1971)
Eioler (1971)
Elsler (1971)
Eialer M971)
*1 mg/1 = 1 ppm
-------
TABLE 6-8 (CONT.)
CADMIUM
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
1,000
tl ht. TI.75 sanduorm, Herein vlren
y96 hr. TL25 sandworm, Nereis virpn
100
0.01
0.001
Eliler (1971)
Eisler (1971)
Eial«r (1971)
Eisler (1571)
Eisler (1971)
Eisler (1971)
Eisler (1971)
EisUc (19711
Eisler (1971)
Eisler (1971!
Eisler (1971)
EisJer (197U
Collier ot al (1973)
Eialec (1971)
Eialcr (1971)
Eialer and Gardner (19
Eislgr (1971)
Eisler (1971)
Eisler (1971)
Eisler (19711
Eialcr (1971)
Eisler [19711
Eisler (1971)
Eisler (1971)
Collier i t al (1973)
Eisler (1971)
Eialer ( 1971 )
Eiil«r (1971)
Eisler (1971)
Eislor (1971)
Eislsr (1971?
EUler (1971)
Eisler (1971)
(1973)
Collier
EUler (1971)
Eislec (1971)
Eisler (1971)
Elaler [1971]
Calabrese {1973)
Eisler U971I
Collier et si. (1973)
Eisler (1971)
Elsler (1971)
Eialer (1971)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Elsler (1971)
Collier et «1. (1973)
Eisler (1971)
Einlrr 11971)
Cfllflbrese [1973)
Collier at al. (1973)
*1 mg/1 = 1 ppm
-------
TABLE 6-8 (CONT.)
CADMIUM
CONCENTRATION (mg/1)'
EFFECT
LOCATION
REFERENCE
1,000
10
0.01
0.001
Eiller (1971)
71)
Eisler (1971)
Eisler (1971)
Eisler (1971)
Elsler (19711
Eisler (1971)
Eisler (1971)
Elilcr 11971)
J8 hr. TL75 sand shrimp, Ctangon sortemspinoaa
II
71)
Eisler (1971)
Eisler (1971)
EisUr [19711
Eisler (1971)
EPA (1973)
tPA (1S73)
*1 mg/1 = 1 ppm
-------
TABLE 6-9
TOXICITY TABLE - CRUDE OILS
CONCENTRATION {mg/1)*
EFFECT
LOCATION
REFERENCE
. 100,000
10,000
1,000
f equilibrium in codfish
4 hr, TLm for Oncorhynchua gorbuscha (pink salmon) fry
thai to Ch 1 Qre 1 l_a a u t o t coph lea (green algae)
urchins) wTuTVfi "6~ ~hT, exp
delayed cull division in CoacinodlB:ua
hr LCSO for cypitnodon variegatua (sbeepshBdfl minno*)
hr LC50 fnr Funclulua aimul
3)
alcr 11973)
rhina (197<)
Eialer 11975)
Sturdevant (1972)
Rice (1^73)
Rice (1973)
Rice (1973)
Elaler (1975
Eiolet (1975)
Eialer (1975)
Kaiinen and Rica (1974)
Rice [1973)
Rice (1973)
Rice (1973)
Pulich at al. U974J
Rice (1973)
Rice (1973)
Rice (1973)
Eifller (1975
Rice (1973)
•?*>
Petkina (1974)
Wells (1972)
Wells (1972)
Spoonar (196B)
Mirohov (1970)
Malacea (1964)
Rice (1973)
Anderson et. al. (1974)
et al (1974)
Morwnaerts-VlUiet (1973)
*1 mg/1= 1 ppm
-------
TABLE 6-9 (CONT.)
TOXICITY TABLE - CRUDE OILS
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
100,000
to 501 in phytoplanKton
dulus simulu
51 reduction in photosynthesis of Enteromorpha intestine]la
(pink salmon) fry at 1. 5° C
hr TL50 for Mysidc Jsis almyrg (mysid)
Photosynthesis reduo-ed in ulva fenestia. Latninaria
96 hr. 1Ui for Henjdu beryllina (silveraide)
96 hr. TLm for pink salmon eggs
Gordon and Prouso 11973)
Anderson et al. (19741
Anderson et al. (1974)
Andi
4)
Malacca et al. (19641
Anderson et il. (19741
Rice et al. 11975)
2)
Xnoeraon et al. 11914)
Anderson et al. (19741
Andi
Rice 11973)
Rice et al. (197<)
Anderson et al. (1974)
Anderson et al. (1974)
Shiela 11973)
Shiels (1973)
Walsh and Kttchell (1973)
Atema and stein 11974}
Shiels 11973)
Shiela (1973)
Hells 1197!)
Eisler (19751
Perkins (1974)
Perkins (1974)
'41
4)
Pcikin» (197J)
Mironov (1970)
Moore et al. (1974)
Moore el al. 119741
And.
(1973)
Anderson ot al. (19741
Anderson et al. (1974)
Shiels 11973)
Shiels (1973)
Anderson et al. (1974)
Anderson et al. (1974)
Rice et al. (1075)
Cairns and Scheier (1962)
Anderson et al. (1974)
Thomas and Rica 11975)
Anderson et al. 11974)
* I rag/1 = 1 ppm
-------
TABLE 6-9 (CONT.)
TOXICITY TABLE - CRUDE OILS
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
100,000
10 day etfpQ&ure had no effect on Chlorocuccum Sp.
(t-hytuplankton)
I day
631 Gadus rr.orrhua (cod) killed during 100 hr. exposure
(grass shrimp)
i pug 11o
wuj_f_i
Ho effect on tjrre to d^ath of larvae of Gadus^ morrhu.
trgchpiJemn (dinof I
of phytoplankton
JHPCF (1972)
Thomas and Rice (1975)
Shiela (1973)
Moore et al. (1974)
JHPCF (1»7J)
Shiels (1973)
Anderson et al. (1974)
Rice (1973)
Thomas and Rice (1975)
Moore et al. (1974)
Moore et al. (19741
Mciora et nl. (1974)
Perkins (1974)
Perkins (1974)
Moore ct al. (1974)
Mooro et al. (1974)
Environmental Studies
Board (1972)
Environmental Studies
Board (1972)
Mironov (1968)
Amlfrflon et al. (1974)
Rice (1973)
Pice (1975)
Shiala (1973)
Perkins (1574)
Perkins 11914)
Perkins (1974)
Perkins (1974)
Perkins (1974)
Moots et al. (1974)
Moore et al. (10741
Moore et al. (1974)
Moore et at, (1974)
Perkins (1974J
Perkins (1974)
Perkins (1974)
Moore et al. (1974)
Mironov (1971) (WQC 1972 342)
Perkins (1974)
Perkins (1974)
*1 mg/1 = 1 pptu
-------
TABLE 6-9 (CONT.)
TOXICITY TABLE - CRUDE OILS
CONCENTRATION (mg/1)'
EFFECT
LOCATION
REFERENCE
100,000
I 10,000
1,000
isb
T
Ttfet*
iTed
—Abnormal development of flounder spawn
-100% increase in photosynthefcic rate of Port Vald-z plankton
Inhibited attraction to food source of HaB_p_a_tiua_ abacietus
(mud mail)
-Stimulates plankton growth
_IntubiteJ feeding and mating responses of male Pashygrapsua
-Increase of carbon uptake in phytoplankton
Mironov (1967) (WQC 1972 3«1)
Menzel (1948)
Mironov (1968)
Shiela (1973)
Shiela (1973)
Atema et fll. (1973)
Gordon 11973)
*1 mg/1 - 1 ppm
-------
TABLE -i 10
TOXICITY TABLE - NICKEL
CONCENTRATION (mg/1)*
EFFECT
LOCATION
REFERENCE
10,000
1,000
100
10
,36 hr. LC100 to Fundulua heteroclitus fertilized eggi
Prevented gastrulntion in embryos of BCO urchin
' Lytechinua El?_tu^
Tolerated by fish for 1-2 wka
/urchin Lytechinua
stia pycifera after 96 hr. expo:
48 hr. LC100 for Crasscg;
'2 day LC50, stickleback
day LC50, Stickleback
yLytechinua pictus
'embryOB
4S 1
1973 Marine Water Quality Criterion
'_4fl hr. LCD for Herctinarla mcrccnaria embryos
'.Arrested development of skeleton at prism stage in developing
Murdock (1953)
I Watchmaker
Murdock [ 19531
Murdock (1953)
Murdock (1953)
Murdack (1953}
*1 mg/1 = 1 ppm
-------
TABLE 6-11
TOXICITY TABLE - PHENOL
CONCENTRATION (mg/1)'
EFFECT
LOCATION
REFERENCE
1,000
100
10 -
0.1
Caused 95% mortality in developing Craiaoatrea egg*
after 48 hr. exposure
.Caused 1001 mortality in Mercenaria mercenaria eggs
after 48 hr. exposure and larvae after 10 day exposure
48 hr. TLm, Artercia salin
48 hr. TLra, Hercenana eggs
hr. LC50, Crangg!
No effect on growth of Harcen^ria mercanari* larvae
riicra after 96 hr. exposure '
Price et al. (19741
Davis and Hldu (1967)
71
Davis and Hidu (1967}
Price et al. (1974)
Davis and Hidu (1967)
DaviB and Hidu (1967)
Portmann
Portmann
Davis and Hidu (1967)
McKee and fcoLf (19G3)
HcKee and Wolf (19631
EPA (1975)
Davin and Hidu (1967)
HCKee and Wolf (1963)
HcKee and Wolf (1963)
*1 mg/1 = 1 ppm
-------
TABLE 6-12
TOXICITY TABLE - ARSENIC
CONCENTRATION (mg/1)'
EFFECT
LOCATION
REFERENCE
100
10
.01
Estuary, England
hr. LC100, erobr
48 hr. LC5U, young
.72 hr. exposure caused "distressed" behavior and 72.31
'decrease in Oj consumption in mud snail, Haasati.ua gbgoletu
1973 Marina Water Quality Criteria
Vernberg and Vernberg (1974)
Perkins (1974)
73]
Vernberg and Vcrnberg (1974)
Haclnnes and Thurberg (197J)
*1 n\g/l = 1 ppm
-------
TABLE 6-13
EFFECTS OF CRUDE OIL FRACTIONS
CONCENTRATION
(ppm)
HYDROCARBON
EFFECT
REFERENCE
LO
I
0.0008 Kerosene: water-soluble
fraction
0.001 Kerosene: water-soluble
fraction
0.004 Kerosene: water-soluble
fraction
0.06 Aromatic fraction of
kerosene
0.08 Water-soluble fraction
dimethylnaphthalenes
0.180 #2 fuel oil
0.7 Dimethylnaphthlenes
0.7 2-methylnaphthlene
0.75-0.8 Bunker C.
1.00-100 Diesel fuel, emulsion
No effect on attraction to scallop homogenates
of Nassc\rius ojsolotus (marine snail
No effect on attraction to oyster extract of
Nassarius obso Ictus (marine snail
Reduced attraction to scallop homogenate of
Nassarius obsoletus (marine snail)
Induced searching behavior in Homerus
americanus (loaster) at distance; repulsed
H. americanus at close range
24-hour LC50 f 51 Penae-us aztecus (Brown shrimp)
Interference with phospholipid metabolism in
marine fish after 180 day exposure suggesting
altered membra le structure
24-hour LC50 for Palaemonetes puglio (Grass
shrimp)
24-hour LC50 for Penaeus aztecus (Brown shrimp)
Increase in crivling and respiration rates of
Littorina littnea (snail)
Loss of photosfnthetic ability by Macrocystis
augustifolia {telp) after 7-day exposure
Jacobson and Boylan
(1973)
Jacobson and Boylan
(1973)
Jacobson and Boylan
(1973)
Atema et al. (1973)
Anderson et al. (1974)
Sabo and Stegeman (in
press) 1975
Anderson et al. (1974)
Anderson et al. (1974)
Hargrave et al. (1973)
Moore et al. (1974)
-------
TABLE 6-13 (CON1?.)
CONCENTRATION
(ppra)
HYDROCARBON
EFFECT
REFERENCE
I
M
OJ
I
1.0 Toluene, naphthalene, 3,4
benxpyrene
2.0 2-methylnaphthlene
1.7 2-methylnaphthalene
2.4 Naphthalene
2.5 Naphthalene
2.6 Naphthalene
•
3.4 1-methylnaphthalene
4.5-5.0 Phenanthrene
4.0-5.0 Naphthalene
4.0-15.0 Benzene
4.0-25.0 Benzene
4.0-25.0 Benzene
4.7 Benzene
Not toxic to Hytilus edulis (mussel) after
6-day exposure
24-hour LC50 for Cyprinodon variegatus
(Sheepshead minnow)
24-hour LC50 for Palaemonetes puglio (Grass shrimp)
24 hour LCBO for Cyprinodon variegatus
(Sheepshead minnow)
24 hour LC50 Panaeus aztecus (Brown shrimp)
24 hour LC50 for Palaemonetes puglio (Grass shrimp)
24 hour LC50 for Cyprinodon variegatus
(Sheepshead minnow)
1 hour exposure fatal to sunfish
1 hour exposure fatal to sunfish
10 percent decrease in survival of Engraulis
mordax (Nortnern anchovy) larvae with 48 hour
exposure
20 to 50 percent increase in abnormal Engraulis
mordax (Nort iern anchovy) T day larvae as a
result of 48 hour exposure
Larvae of Engraulis mordax (Nothern anchovy.
larger at da'' 6
10 percent decrease in 3 day survival of
Engraulis mo :da_x (Northern anchovy) larvae
following 24 hour exposure
Moore et al. (1974)
Anderson et al. (1974)
Anderson et al. (1974)
Anderson et al. (1974)
Anderson et al. (1974)
Anderson et al. (1974)
Anderson et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Struhsaker et al. (1974)
Struhsaker et al. (1974)
Struhsaker et al. (1974)
Struhsaker et al. (1974)
-------
TABLE 6-13 (CONT. )
CONCENTRATION
(ppm)
HYDROCARBON
EFFECT
REFERENCE
U)
Ui
I
4.7-55.0
5.0
5.0
5.0
5.1
6.7
10.0
10.0
10.0
10.0
Benzene
Kerosene
Benzene
Benzene
Dimethylnaphthalene
Benzene
Benzene
Benzene
Benzene
Methylcyclohexane
20 percent increase in abnormal Engraulis
mordax (Northern anchovy) larvae at day 6
following 24 hour exposure
Tainting of Mugil cephalus (mullet) tissue
80 percent increase in oxygen consumption rate
of Oncorhynchus tshawytscha (Chinook salmon) after
48 hours of exposure; subsequent decrease to 130
percent of noimal value at 96 hours
Increased oxygen consumption in Morone saxa :ilis
(Striped bass) to 24 hour peak of 130 to 145 percent
of the normal value, with subsequent return to normal
24 hour LC50 for Cyprinodon variegatus (Sheepshead
minnow)
Growth rate of Clupea pallasi (Herring) larvae
decreased by 48 hour exposure
48 hour exposure produced 120 percent increase
in oxygen consumption in Oncorhynchus tshawytscha
(Chinook salmon), with a return to normal consump-
tion at 96 hours
Decreased oxyqen consumption in Morone saxatilis
(Striped bass) after 24 to 48 hours of exposure,
with a return to normal by 96 hours
3 to 4 hour exposure produced lethal toxicicy
in Rutilis sp. (Roach)
3 to 4 hour exposure produced lethal toxicity
in Rutilis sp. (Roach)
Struhsaker et al. (1974)
Connel (1971)
Brocksen and Bailey
(1973)
Brocksen and Bailey
(1973)
Anderson et al. (1974)
Struhsaker et al. (1974)
Brocksen and Bailey
(1973)
Brocksen and Bailey
(1973)
Moore et al. (1974)
Moore et al. (1974)
-------
TABLE 6-13 (CONT.)
CONCENTRATION
(ppm)
HYDROCARBON
EFFECT
REFERENCE
U)
CTi
I
10.0
10.0
10.0
10.0
12.1
22.0-65.0
25.0-50.0
38.0
Benzene
n-hexane
Toluene
Cyclohexane
Benzene
Xylene, toluene,
benzene, ethylene
O-xylene
25.0-250.0 Toluene
25.0-500.0 Benzene
Kerosene
40.0-400.0 #2 fuel oil
40.0-55.0 Benzene
Slight photasynthesis inhibition in Macrocystic
augustifolia (Kelp) caused by 96 hour exposure
No effect of Macrocystic augustifolia (Kelp)
seen with 9 > hour exposure
96 hour expssure resulted in visible injury,
75 percent "eduction in photosynthesis of
Macrocystic augustifolia Kelp)
3 to 4 hour exposure produced lethal toxicity
in Rutilis sp. (Roach)
25 percent mortality of Clupea pallasi (Herring)
larvae after 48 hour exposure
Lethal toxicity to sunfish
Slight inhibition of growth of Chlorella vulgaris
(Phytoplankt-.cn) , 10 day exposure
Slight inhibition of growth of Chlorella vulgaris
(PhytoplankLon), 10 day exposure
Initial inh: bition for 2 days, then growth of
Chlorella vulgaris during 10 day exposure
Depresses gi owth rate of Asterionella japonica
(diatom)
Lethal to Thalassiosira pseudonana (diatom)
Larvae of Ei.gcaulis mordax (Northern anchovy)
smaller at ciays 3 and 6 after 24 hour exposure
Moore et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Struhsaker et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
Aubert et al. (1969)
Pulich et al. (1974)
Struhsaker et al. (1974)
-------
TABLE 6-13 (CONT.)
u>
CONCENTRATION
(ppm)
45.0
45.0
57.0
100.0
500.0
HYDROCARBON
Benzene
Benzene
Kerosene
Tetralin
Toluene
500-1,744 Benzene
EFFECT
20 percent increase in abnormalities, 10 percent
decrease in survival in Clupea pallasi (Herring)
eggs as a result of 24 hour exposure
50 percent mortality of Clupea pallasi (Herring)
eggs
Toxic to Astt r Lonella japonica (diatom)
Exposure up to 6 days toxic to Mytilus edulis
(Mussel)
Lethal toxicity to Chlorella vulgaris (Phytc-
plankton) with 10 day exposure
Lethal toxici ty to Chlorella vulgaris^ (Phyto-
plankton) wit h 10 day exposure
REFERENCE
Struhsaker et al. (1974)
Struhsaker et al. (1974)
Aubert et al. (1969)
Moore et al. (1974)
Moore et al. (1974)
Moore et al. (1974)
-------
REFERENCES FOR TABLES 6-2 to 6-
Barnes and Stanbury. "The Toxic Action of Copper and Mercury
Salts Both Separately and When Mixed on the Harpacticid
Copepod Nitocra." Journal of Experimental Biology
25(3) (1948): 270-275.
Bryan and Hummerstone. "Adaptation of the Polychaete Nereis
diversicolor to Estuarine Sediments Containing High
Concentrations of Heavy Metals." Journal of the Marine
Biological Association of the United Kingdom 51 (1971):
845-863.
Calabrese, A. et al. "The Toxicity of Heavy Metals to Embryos
of the American Oyster Crassostrea 'virginica." Marine
Biology 18 (1973): 162-166.
Collier, R.S. et al. "Physiological Response of Mud Crab
Eurgpanopeus depressus to Cd." Bulletin of Environmental
Contamination Toxicology 10 (1973): 378-382.
Corner, E.D.S. and Sparrow, B.W. "The Modes of Action of
Toxic Agents. I. Observations on the Poisoning of
Certain Crustaceans by Copper and Mercury." Journal
of the Marine Biological Association of the United
Kingdom 35 (1956): 531-548.
DeCoursey and W.P. Verberg. "Effect of Mercury on Survival,
Metabolism and Behavior of Larvae Uca pugilator."
Oikos 23 (1972): 241-247.
Eisler, R. "Cadmium Poisoning in Fundulus heteroclitus
(Pisces: Cyprinodontidae) and Other Marine Organisms."
Journal of the Fisheries Research Board of Canada
28 (9) (1971) : 1225-1234.
Eisler, R. and Gardner, G.R. "Acute Toxicology to an Estuarine
Teleost of Mixtures of Cadmium, Copper and Zinc Salts."
Journal of Fish Biology 5 (1973): 131-142.
Gardner, G.R. and Yevich, P.P. "Histological and Hermatologi-
cal Responses of an Estuarine Teleost to Cadmium."
Journal of the Fisheries Research Board of Canada
27(52) (1970): 2185-2196.
Herbert and Wakeford. "The Susceptibility of Salmoned Fish
to Poisons Under Estuarine Conditions. I. Zinc Sulfate."
Air and Water Pollution 8 (1964): 251-256.
Hunter, W.R. "The Poisoning of Marino gammarus marinus by
Cupric Sulfate and Mercuric Chloride." Journal of
Experimental Biology 26(2): 113~124.
-138-
-------
REFERENCES FOR TABLES 6-2 to 6-7 (CONT.)
Jackim et al. "Effects of Metal Poisoning on Five Liver
Enzymes in the Killifish Fundulus heteroclitus."
Journal of the Fisheries Research Board of Canada
27 (2) (1970) : 333-391.
Jones. "The relative toxicity of the salts of Pb, Zn and
Cu to the Stickleback (Gasterosteus aculeatus L.).
Journal of Experimental Biology 15 (1938): 394-407.
Kania and O'Hara. "Behavioral Alterations in a Simple
Predator-Prey System Due to Sublethal Exposure to
Mercury." Trans. Am. Fish Soc. 103(1) (1974): 134-136.
Maclnnes and Thurberg. "Effects of Metals on the Behavior
and Oz Consumption of the Mud Snail." Marine Pollution
Bulletin 4 (1973): 185-186.
Pyefinch and Mott. "The Sensitivity of Barnacles and Their
Larvae to Cu and Hg." Journal of Experimental Biology
25 (1948): 276-298.
Raymont and Shields. "Advances in Water Pollution Research."
Proc. Int. Conf., London, 1962.
Sprague, J.B. "Lethal Concentrations of Copper and Zinc
for Young Atlantic Salmon." Journal of the Fisheries
Research Board of Canada 21(1) (1964): 17-26.
Sprague, J.B. and Ramsay, B.A. "Lethal Levels of Mixed
Copper-Zinc Solutions for Juvenile Salmon." Journal
of the Fisheries Research Board of Canada 22(2) (1965):
425-432.
Sprague, J.B. et al. "Sublethal Copper-Zinc Pollution in a
Salmon River: A Field and Laboratory Study." Inter-
National Journal of Air and Water Pollution 9 (1965):
531-543.
Stephenson, R.R. and Taylor, D. "Influence of EDIA on
Mortality and Burrowing Activity of Clam (Venerupsis
decussata Exposed to Sublethal Concentrations of Copper."
Bulletin of Environmental Contamination Toxicology 14(3)
(1975): 304-308.
U.S. Environmental Protection Agency. Water Quality Criteria
1973>
-139-
-------
REFERENCES FOR TABLES 6-2 to 6-7 (CONT.)
Ventilla, R.J. and Gray, J.S. "Growth Rates of a Sediment-
Living Marine Protozoon as a Toxicity Indicator for
Heavy Metals." Ambio 2(4) (1973): 118-121.
Wisely, B. and Blick, R.A.P. "Mortality of Marine Inverte-
brate Larvae in Mercury, Copper and Zinc Solutions."
Austr. J. Mar. Fresh Res. 18(1) (1967): 63-72.
-140-
-------
REFERENCES FOR TABLES 6-8 to 6-13
Pulich, W.M. et al. "The Effects of a No. 2 Fuel Oil and
2 Crude Oils on the Growth and Photosynthesis of
Microalgae." Marine Biology 28 (1974): 87-94.
Nuzzi, Robert. "Effects of Water Soluble Extracts of Oil
on Phytoplankton." API Proceedings Joint Conference
on Prevention and Control of Oil Spills. Washington,
D.C., 1973.
Dunning, A., and Major, C.W. "The Effect of Cold Seawater
Extracts of Oil Fractions upon the Blue Mussel, Mytilus
Edulis." Pollution and Physiology of Marine Organisms.
Ed. by F. Vernberg and W. Vernberg. New York: Academic
Press, 1974.
Moore, S.F., Chirlin, G.R., Puccia, C.J., and Schrader, B.P.
Potential Biological Effects of Hypothetical Oil
Discharges in the Atlantic Coast and Gulf of Alaska.
Cambridge: Massachusetts Institute of Technology, 1974.
U.S. Environmental Protection Agency. Environmental Studies
Board. Water Quality Criteria 1973.
Eisler, R. "Latent Effects of Iranian Crude Oil and a
Chemical Oil Dispensant on Red Sea Mollusks." Israel
Journal of Zoology 22 (1973) : 97.
Rice, Stanley et al. "The Effect of Prudhoe Bay Crude Oil
on Survival and Growth of Eggs, Alevins, and Fry of
Pink Salmon, Oncorhynchus gorbuscha." API Proceedings
Joint Conference on the Prevention and Control of Oil
Spills. Washington, D.C., 1975, p. 503.
Brocksen, R.W. and Bailey, H. "Respiratory Response of
Juvenile Chiwook Salmon and Striped Bass Exposed to
Benzene, A Water Soluble Component of Crude Oil."
API Proceedings Joint Conference on the Prevention
and Control of Oil Spills. Washington, D.C., 1973.
Anderson, J.W. et al. "The Effects of Oil on Estuarine
Animals: Toxicity, Uptake and Depuration, Respiration."
Pollution and Physiology of Marine Organisms. Ed. by
F. Vernberg and W. Vernberg. New York: Academic
Press, 1974.
-141-
-------
REFERENCES FOR TABLES 6-8 to 6-13 (CONT.)
Jacobson, S.M. and Boylan, D.B. "Seawater Soluble Fraction
of Kerosene: Effects on Chemotaxis in a Marine Snail,
Nassarius Obsoletus." Nature 241 (1973): 213.
Stegeman, John. "Hydrocarbons in Shellfish Chronically
Exposed to Low Levels of Fuel Oil." Pollution and
Physiology of Marine Organisms. Ed. by F. Vernberg
and W. Vernberg. New York: Academic Press, 1974.
Brown, D.H. "The Effect of Kuwait Crude Oil and a Solvent
Emulsifier on the Metabolism of the Marine Lichen
Lichina Pygmaea." Marine Biology 12 (1972) : 309-315.
Galtsoff, Paul S. "Experimental Studies of the Effect of
Oil on Oysters: Review of the Lit." Bulletin Bureau
Fish. 48 (1935): 158.
Anderson, J.W. et al. "Characteristics of Dispersions and
Water-Soluble Extracts of Crude and Refined Oils and
Their Toxicity to Estuarine Crustaceans and Fish."
Marine Biology 27 (1974): 75-88.
Struhsaker, J.W., Eldridge, M.B., and Echeverria, T.
"Effects of Benzene (A Water-Soluble Component of
Crude Oil) on Eggs and Caruae of Pacific Herring and
Northern Anchovy." Pollution and Physiology of Marine
Organisms. Ed. by Vernberg & Vernberg. New York:
Academic Press, 1974.
Perkins, E.J. The Biology of Estuaries and Coastal Waters.
New York: Academic Press, 1974.
Shiels, W.E. "Effects of Crude Oil Treated Seawater on the
Metabolism of Phytoplankton and Seaweeds." Thesis
(M.S.), University of Alaska, 1973.
Neff, J. "Oil Pollution and Shellfish." Proceedings of
8th National Shellfish Sanitation Workshop, 1974,
pp. 72-76.
Rice, Stanley. "Toxicity and Avoidable Tests of Prudhoe Bay
Oil and Pink Salmon Fry." API/EPA/USCG Proceedings.
Joint Conference on the Prevention and Control of Oil
Spills. Washington, D.C., 1973.
-142-
-------
REFERENCES FOR TABLES 6-8 to 6-13 (CONT.)
Gordon, D.C. and Prouse, N.J. "The Effects of 3 Oils on
Marine Phytoplankton Protosynthesis." Marine Biology
22 (1973) : 329-333.
Takahashi, F.T. and Kittredge, J.S. "Sublethal Effects of
the Water Soluble Component of Oil: Chemical Communi-
cation in the Marine Environment." Microbial Degradation
of Oil Pollutants. Ed. by D.G. Ahearn and S.P. Meyers.
Baton Rouge: LSU Center for Wetland Resources.
LSU-SG-73-01, 1973, pp. 259-264.
Hargrave, B.T. and Newcombe, C.P. Journal of the Fisheries
Research Board of Canada 30(12) (1973): 1789-1792.
Sabo, D. and Stegeman, J. "Some Metabolic Effects of
Petroleum Hydrocarbons in Marine Fish." (in press) 1975.
Shiells III, W.E. "Effects of Crude Oil Treated Seawater on
the Metabolism of Phytoplankton and Seaweeds." Masters
Thesis, University of Alaska, 1973.
Rice, S.D., Moles, D.A., and Short, J.W. "The Effect of
Prudhoe Bay Crude Oil on Survival and Growth of Eggs,
Alevins and Fry of Pink Salmon Oncorhynchus gorbuscha.
Proceedings of Joint Conference on Prevention and
Control of Oil Pollution, 1975, pp. 503-507.
Stegeman, J.J. and Teal, J.M., "Accumulation, Release and
Retention of Petroleum Hydrocarbons by the Oyster
Crassostrea virginica." Marine Biology 22 (1973) :
37-44.
Atema, J., Jacobson, S., Todd, J., BoyIan, D. "The Importance
of Chemical Signals in Stimulating Behavior of Marine
Organisms: Effects of Altered Environmental Chemistry
on Animal Communications." Chapter 9, Bioassay
Techniques and Environmental Chemistry (1973): 177-197.
Menzel, R.W. Report on Two Cases of Oily Tasting Oysters at
Bale Sainte Elaine Oilfield. Texas A&M Research Founda-
tion. College Station, 1948.
Thomas, R.E. and Rice, S.D. "Increased Opercular Rates of
Pink Salmon (Oncorhynchus gorbuscha) Fry after Exposure
to Water-Soluble Fraction of Prudhoe Bay Oil." Journal
of the Fisheries Research Board of Canada 32 (11) (1975) :
2221-2224.
-143-
-------
REFERENCES FOR TABLES 6-8 to 6-13 (CONT.)
Mironov, O.G. "The Effect of Oil Pollution on the Flora and
Acartia of the Black Sea." FAO Tech. Conference on
Marine Pollution, Rome, 1970, pp. i-92.
-144-
-------
6.3.2 Sublethal Effects
Tables 6-2 through 6-13 deal with a number of different
toxic effects, primarily lethality, but including a number
of important sublethal effects. Although sublethal effects
might not result in direct mortality, they can nevertheless
have severe ecological consequences if they decrease the
rate at which organisms can find food, escape predation, or
produce offspring. Although the majority of past work has
dealt with parameters of lethality, the direction of current
research is towards further exploration of important sub-
lethal interactions. Among the important sublethal effects
of brine pollutants are:
1. "Economic effects," i.e., effects which reduce
the marketability of economically important marine
organisms. An example is the "greening" of oysters
in solutions containing moderate concentrations of
copper, due to the bioaccumulation of copper by
the organism.
2. Histo- and cytopathology -- Exposure to sublethal
concentrations of trace metals and hydrocarbons
has been shown to produce extensive tissue damage,
at the light or electron microscope levels, in
gill, kidney, and liver tissue. Such damage can
reduce life expectancy and productivity, and, if
it occurs in lateral line or taste bud tissues,
can reduce the extent to which a fish can find
food or avoid predation.
3. Biochemical alterations -- Some studies are
reported in the tables of the effect of trace
metals on the assay levels of certain key enzymes
in fish, and other studies have tried to determine
by electrophoresis the effect of sublethal expo-
sures on the concentrations of various serum
proteins. The use of acetylcholinesterase levels
as an indicator of exposure to certain organo-
phosphorus pesticides has received particular
attention. Although such biochemical parameters
are hard to interpret in terms of effects on
ecosystems, they seem to indicate pathological
conditions which have the potential of reducing
the survival rates, fertility, or adaptability of
a species.
4. Physiological parameters -- Included in this
category are effects on blood ion concentration,
EKG rates, blood cholesterol levels, or hematocrit
-145-
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levels of affected fish populations. A small
number of studies have been conducted on the
effects of pollutants on these parameters, par-
ticularly on freshwater fish; an excellent review
is provided by Sprague.^ Again, data such as
these are hard to interpret directly, but they can
be used as "early warning signs" of potentially
dangerous toxic conditions.
5. Effects on growth and productivity.
6. Effects on viability, as indicated by rates of C>2
consumption, particularly in gill tissue.
7. A toxic substance, even if it creates no notice-
able toxic effects by itself, can significantly
reduce the resistance of an organism to other
environmental stressors, including DO stress,
salinity stress, and thermal stress.
8. Behavioral effects -- Included in this category
are effects on mating or swimming behavior which
might affect survival and growth rates of the
organism and species. Another important sublethal
behavioral response to pollutants is the avoidance
response; that is, the avoidance by fish of waters
which contain particular levels of a trace metal.
Such an effect is important because it can prevent
spawning migrations of fish. Sprague et al.^
note that "in the laboratory, avoidance responses
can be obtained at less than one-tenth of the
incipient lethal level (i.e., threshold) concen-
trations." Such behavioral effects are most
important if they affect behavioral patterns
important for survival. Stephenson and Taylor,
for example, have noted a decrease in burrowing
activity of clams associated v/ith sublethal copper
toxicosis^ and in an elegant experimental system
involving the use of a radioactive mercury tracer,
4
Sprague, "Measurement of Pollutant Toxicity of Fish,"
p. 257.
bJ.B. Sprague et al., "Sublethal Copper-Zinc Pollution
in a Salmon River: A Field and Laboratory Study," International
Journal of Air and Water Pollution 9 (1965) : 531-545.
Stephenson and Taylor, "Influence of ETDA on Mortality
and Burrowing Activity of Clams."
-146-
-------
Kania and O'Hara demonstrated that sublethal
exposures to mercury(II) reduced the efficiency
of the mosquitofish Gambusia in escaping predation
by the bass Micropterus.7
9. Reproductive effects -- Data in the tables include
some effects of trace metals on development. Such
effects can range from lethality of eggs and
embryos to minor developmental defect initiation
(teratogenesis) which could reduce the survival
rate of the hatched young. Generally, such
effects occur at levels far below the lethal
concentrations for the organisms.
10. Aggregate effects on production in communities --
A few experiments have been done on the effects of
pollutants on harvestable crops, productivity, and
diversity in natural freshwater ecosystems; pre-
sumably, in the near future similar studies will
be initiated in marine or estuarine systems.
11. Effects on performance (e.g., swimming ability).
12. Effects on disease resistance.
Each of the effects discussed above is important in
that it can produce gross alternations in the populations,
productivity, and diversity of a community without producing
any significant mortality effect in a laboratory bioassay
system. For this reason, it is important that available
data on sublethal effects can be taken into account in
setting standards, and that such standards not be designed
to simply prevent significant direct mortality as a result
of exposure to a pollutant.
6.3.3 Restrictions of the Data Base
Ideally, toxicological data would provide us with
precise qualitative and quantitative descriptions of the
effects which can be expected in particular organisms in the
presence of specific levels of pollutants. In practice,
this is made impossible by the highly complex nature of the
pollutant toxicity problem. Consider, for example, the
problems associated with the assessment of oil toxicity.
Kania and O'Hara, "Behavorial Alterations in a Simple
Predator-Prey System Due to Sublethal Exposure to Mercury,"
Transactions of the American Fisheries Society (1) (1974):
134-136.
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First, oil itself is not a chemically well-defined substance,
but a complex mixture of literally 'hundreds of organic and
inorganic compounds, each with its own specific toxicological
properties. Since oils from various parts of the world
differ widely in their content of specific substances, "oil"
per se can have no well-defined toxicity. Furthermore, even
though extensive data are available on the toxicity of some
of the individual components of crude oils, their effects
when mixed together can be complicated by a variety of
synergistic or antagonistic interactions. An additional
problem arises from the fact that none of the components of
oil are stable through time, either with respect to their
physical form, their chemical composition, or their distri-
bution over sediments and the dissolved and suspended
fractions of the region being considered (as is discussed in
Appendix C).
The reaction of an organism to toxic pollutants will be
modified by a number of environmental factors; so that the
wide diversity of possible environments, combined with the
even greater difference between any natural marine environ-
ment and a laboratory bioassay system, make it practically
impossible to extrapolate toxicity data obtained in one
experimental system under a highly specific set of condi-
tions to any other system or any other set of conditions.
According to Evans and Rice:8
Within these environments are several...physical
conditions such as temperature, salinity, oxygen, and
nutrient concentration, as well as biological differ-
ences such as species composition, diversity and
density, and community metabolic rate. The prediction
or assessment of pollution effects on the basis of
observations extrapolated from one environment to
another is seldom supported by adequate data. Unfor-
tunately, however, few data on pollution effects exist
for most areas and species, which has led to the use of
information from areas that may be dissimilar in
critical ways.
Another problem involved in the application of pub-
lished laboratory or field data to the assessment of pollu-
tant effects was recently discussed by Smith:9
D.R. Evans and S.D. Rice, "Effects of Oil on Marine
Ecosystems: A Review for Administrators and Policy Makers,"
Fishery Bulletin 72 (1974): 625.
9
A.N. Smith, Oil Pollution and Marine Ecology (London:
Plenum Press, 1973) , p. 99~I
-148-
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Data about the effects of oil pollution on marine
plants and animals have been obtained from experiments
in the field or laboratory and from observations of
actual incidents or chronically polluted habitats...
Toxicity tests in the laboratory are usually designed
to result in death in a few days, so they cannot be
expected to reveal long-term effects. They are often
made on organisms which are convenient for experimen-
tation rather than important in a threatened environ-
ment; different results are obtained according to they
way in which the pollutant is applied, the life-stage
of the organism used or the season in which it is
collected and tested, so that tests made in different
laboratories may be far from comparable. Often the
importance of these factors was not realized when the
tests were made, so that many of the circumstances
surrounding them were not recorded. In the field,
factors other than the pollutant may also be at work
and are rarely under the control of the observer, if
they are even known to him; adequate measurement of
those contributory factors which are recognized cannot
usually be made, so that reports are often incomplete
and anecdotal.
Because of these factors, toxicity data reported even
for a single compound and a single organism may exhibit wide
variation; it has been reported, for example, that LC50 data
collected at different laboratories for a single substance
may show a standard deviation of close to one-quarter of the
mean.10 These factors must be kept in mind in applying the
data given on the toxicity tables.
Available data permit neither valid quantitative
extrapolation of data from one environment to another, nor
the accurate prediction of the effect of such factors as
weathering and emulsification on the toxicity of crude oil
to individual organisms and its overall effect on ecosys-
tems. Nevertheless, any consideration of the analysis
performed in this report should be done with at least a
qualitative understanding of the important factors modifying
toxicity in the marine environment. This discussion is
intended to emphasize these factors.
Of course, one of the principal factors affecting the
long-term toxicity of pollutants is the existence of envi-
ronmental processes which can degrade or transform them, or
result in their transfer between different compartments of
W.R. Hunter, "The Poisoning of Marinogammarus marinus
by Cupric Sulphate and Mercuric Chloride," Journal of
Experimental Biology 26(2) (1949): 113-124.
-149-
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the marine environment (water, bottom sediments, suspended
particulates, etc.). These processes are discussed in
Appendix C, and they can have a significant effect on the
toxicity of the compound involved. Microbial or photo-
chemical degradation processes, for example, will ultimately
eliminate hydrocarbon toxicants from the marine environment
and therefore reduce the toxicity problem created by them.
Nevertheless, some of the intermediates in the degradation
process can be even more toxic than their precursors.
The toxicity of trace metals in particular will be
affected by sedimentation, but the data on the relative
toxicities of the dissolved and precipitated forms of
various metals are sparse and occasionally contradictory.
Generally, dissolved metals can be expected to be more
accessible to living organisms than suspended ones, except
for filter feeders or benthic burrowing organisms (e.g.,
Nereis sp.). These observations should be considered in the
light of the general rule, enunciated by Bryan, that "in the
absence of much evidence to the contrary, it seems reasonable
to suppose that most of the factors affecting toxicity owe
their influence to changing the rates at which metals are
absorbed" or the extent to which they are available for
biological absorption.-1--1-
Other transformations to which hydrocarbons and trace
metals are subject in the marine environment, such as
adsorption, complexation, oxidation and reduction, and
biological transformation can also affect their toxicity.
Some examples are:
12
1. Chelation -- Experiments with oysters have shown
that toxic effects of high levels of copper are
reduced or eliminated in the presence of chelating
agents such as EDTA. Presumably, the organometal
complex is less readily absorbed by the organism
than is the metal ion itself. Similar effects may
be observed in the marine environment with natural
complexing agents. Some experiments have been
performed with cyanide and ammonium complexes of
copper, with the result that complexation gener-
ally lowers the toxicity of a particular metal.
11G.W. Bryan, "The Effect of Heavy Metals (Other than
Mercury) on Marine and Estuarine Organisms," Proceedings of
the Royal Society of London 177 (1971): 389.
12Stephenson and Taylor, "Influence of EDTA on Mortality
and Burrowing Activity of Clams."
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2. Biological transformations -- In situ biological
transformations may drastically affect the availa-
bility or toxicity of a trace metal. One example
of this which has received particularly intensive
study is the microbial transformation of Hg ions
into highly toxic methylmercury compounds. A
number of recent reviews have dealt with the rate
of this process and its implications for the
environmental toxicology of mercury.13
3. Oxidation -- Cuprous antifouling compounds have
been found to undergo slow but spontaneous oxida-
tion to the cupric form in seawater, and similar
oxidations may occur for other transition elements
in seawater, for example, mercury (Hg+ to Hg++)
and chromium (Cr+++ to Cr +6). In many cases, the
toxicity of the oxidized species can differ greatly
from that of the reduced form. For example,
trivalent chromium compounds are known to be much
less toxic than the corresponding hexavalent
forms.
Such effects are often not simulated in laboratory
bioassay systems, but are nonetheless important in modifying
the toxicity of a trace metal to a test organism. Further-
more, the bioassay procedure itself may produce a variety of
artifacts not representative of interactions in the marine
environment. For example, Collier et al.^-4 note that in
static bioassay systems, scavenging of pollutants from
solution by some of these processes may exceed the rates at
which such scavenging occurs in a natural environment:
"There are certain disadvantages inherent in tests performed
in static water. Among these are possible loss of toxicant
See S. Jensen and A. Jernelov, "Biological Methylation
of Mercury in Aquatic Organisms," Nature 223 (1969): 753;
and S. Skerfving, "Mercury in Fish -- Some Toxicological
Considerations," Food and Cosmetic Toxicology 10 (1972) :
545-556.
14
R.S. Collier et al., "Physiological Response of the
Mud Crab, Euypanopeus depressus, to Cadmium," Bulletin of
Environmental Contamination and Toxicology 10(6) (1973) :
380.
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via aeration, adsorption of the toxicant by the container,
and uptake of the toxicant by the test animal."15
Other factors, including the existence of other environ-
mental stresses (such as thermal or dissolved oxygen stress),
and the conditions or life-cycle stage of the affected
organism, can also influence the toxicity of pollutants in
the marine environment. Table 6-14 summarizes some of the
important factors influencing trace metal toxicity in the
marine environment. Factors influencing hydrocarbon toxicity
are summarized in Table 6-15.
6.3.4 Interpretation of Data
Data on lethality, which is still the most abundant
form of toxicological data for marine organisms, are reported
in three key ways:
1. Measures of average percent mortality at a given
level of exposure to a toxic substance (other
factors held constant) for various lengths of
time. The measure used here is known as the LT
(lethal time)- n, where n is the percent mortality
observed in a population. This statistic is only
meaningful if a particular concentration or dose
of a toxic substance is specified. A 50 ppm LT50,
then, refers to the mean exposure time necessary
to cause 50 percent mortality in a population
exposed to 50 ppm of a toxic substance. Needless
to say, this statistic, like the ones below, is
both substance- and organism-specific.
2. Measures of average percent mortality at a given
time of exposure to a toxic substance (other
factors held constant) for various levels of
exposure. The measure is known as LC (lethal
In other words, the metal may be absorbed on the
cuticle of the animal or on other body surfaces where it
would have essentially no physiological effect. This pro-
cess would result in a decrease in the effective metal
concentration to which the organism is exposed, and could
only be prevented in some sort of flow-through (non-static)
bioassay system. This absorption of metal ions on external
body surfaces is also important to keep in mind in inter-
preting bioaccumulation data: if accumulation in the whole
organism is measured, substantial artifacts are created by
the high, but physiologically irrelevant amounts of metal on
the external cuticle.
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TABLE 6-14
FACTORS INFLUENCING THE TOXICITY OF
HEAVY METALS TO AQUATIC ORGANISMS
I
H1
t_n
U)
I
FACTORS
ion
FORM OF METAL IN WATER
complex
Soluble chelate
compound
Particulate / ?«<*?**«*«
^ adsorbed
PRESENCE OF OTHER
METALS OR POISONS
FACTORS INFLUENCING
PHYSIOLOGY OF ORGANISM
AND POSSIBLY FORM OF
METAL IN WATER
CONDITION OF
THE ORGANISM
Antagonistic Effects
Additive Effects
Synergistic Effects
Salinity
Temperature
Dissolved Oxygen
pH
Light?
Stage in Life-history
Changes in Life-cycle
(e.g. Moulting)
Size of Organism
Activity of Organism
Acclimatization to Metals
REFERENCES3
Clarke (1947)
Doudoroff (1956)
Grande (1967)
Corner & Sparrow (1957);
Clarke (1947)
Herbert & Wakeford (1964)
Lloyd & Herbert (1962)
Brown (1968)
Corner (. Sparrow (1956)
Herbert & Wakeford (1964)
Lloyd & Herbert (1962)
Lloyd (1961)
Sprague (1964a)
Gutnecht (1963)
fyefinch & Mott (1948)
.'Jkidmore (1967)
Herbert & Shurben (1963)
Edwards S Brown (1967)
METALS
Cu
Cu, Zn, Cd, Ni
Cu, Zn
Hg, Cu
Zn
Ca on Zn, Cu, Pb
Zn, Cu, Phenol,
Cyanide, Ammonia
Cu, Hg
Zn
Zn
Zn , Cu , Pb
Zn
Zn
Cu
Zn
Zn
Zn
ORGANISMS
Crustaceans
Fish
Fish
Crustaceans
Fish
Fish
Fish
Crustaceans
Fish
Fish
Fish
Fish
Seaweed
Crustaceans
Fish
Fish
Fish
Complete references for this table may be found on the following two pages.
Source: G.W. Bryan, "The Effects of Heavy Metals (Other Than Mercury) on Marine
and Estuarine Organisms," Proceedings of the Royal Society of London 177 (1971): 389-410
-------
REFERENCES FOR TABLE 6-14
Clarke, G.L. "Poisoning and Recovery in Barnacles and Mussels."
Biological Bulletin 92 (1947): 73-91.
Doudoroff, P. "Some Experiments on the Toxicity of Complex
Cyanides to Fish." Sewage and Industrial Wastes 28 (1956):
1020-1040.
Grande, M. "Effect of Copper and Zinc on Salmonid Fishes."
Advances in Water Pollution Research 1 (1967) : 97-111.
Corner, E.D.S., and Sparrow, B.W. "The Modes of Action of
Toxic Agents. II. Factors Influencing the Toxicities of
Mercury Compounds to Certain Crustacea." Journal of the
Marine Biological Association of the United Kingdom 36
(1957): 459-472.
Herbert, D.W.M., and Wakeford, A.C. "The Susceptibility of
Salmonid Fish to Poisons Under Estuarine Conditions.
I. Zinc Sulphate." International Journal of Air and
Water Pollution 8 (1964) : 251-256.
Lloyd, R., and Herbert, D.W.M. "The Effect of the Environment
on the Toxicity of Poisons to Fish." Institution of
Public Health Engineers Journal 61 (1962) : 132-145.
Brown, V.M. "The Calculation of the Acute Toxicity of Mixtures
of Poisons to Rainbow Trout." Water Research 2 (1968):
723-733.
Corner, E.D.S., and Sparrow, B.W. "The Modes of Action of Toxic
Agents. I. Observations on the Poisoning of Certain
Crustaceans by Copper and Mercury." Journal of the Marine
Biological Association of the United Kingdom 35 (1956):
531-548.
Lloyd, R. "Effect of Dissolved Oxygen Concentrations on the
Toxicity of Several Poisons to Rainbow Trout (Salmo
gairdnerii Richardson)." Journal of Experimental Biology
38 (1961) 447-455.
Sprague, J.B. "Lethal Concentrations of Copper and Zinc for
Young Atlantic Salmon." Journal of the Fisheries Research
Board of Canada 21 (1964) : 17-26.
-154-
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REFERENCES FOR TABLE 6-14 (CONT.)
Gutnecht, J. "An Uptake by Benthic Marine Algae." Limnology
and Oceanography 8 (1963): 31-38.
Pyefinch, K.A. and Mott, J.C. "The Sensitivity of Barnacles and
Their Larvae to Copper and Mercury." Journal of Experi-
mental Biology 25 (1948): 276-298.
Skidmore, J.F. "Oxygen Uptake by Zebrafish (Brachydanio rerio)
of Different Ages in Relation to Zinc Sulphate Resistance."
Journal of the Fisheries Research Board of Canada 24
(1967) : 1253-1267) .
Herbert, D.W.M., and Shurben, D.S. "A Preliminary Study of the
Effect of Physical Activity on the Resistance of Rainbow
Trout (Salmo gairdnerii Richardson) to Two Poisons."
Annals of Applied Biolo'gy 53 (1963): 321-326.
Edwards, R.W., and Brown, V.M. "Pollution and Fisheries: A
Progress Report." Water Pollution Control 66 (1967):
63-78.
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TABLE 6-15
FACTORS AFFECTING PETROLEUM TOXICITY
FACTOR
EXAMPLE
REFERENCE
Oil Type
Turbidity
en
CTl
i
Season
Nature of
Substrate
Synergisms
Oils high in aromatic hydrocarbon content
tend to have high toxicity.
Suspended particulates adsorb hydrocarbons
and accelerate oil sedimentation. The
transfer of hydrocarbons to the sediment
is generally advantageous to tidal life
and detrimental to benthic life.
Sensitivity to toxicants can vary on a
seasonal basis or between different
lifecycle stages. Juvenile forms may
be particularly sensitive.
Oil will tend to percolate into coarse,
sandy sediments, allowing closer contact
with infauna. Nature of sediment affects
rate and degree of hydrocarbon adsorption.
Adsorption affects availability to biota
and rate of microbial degradation.
Environmental stressors such as salinity
and DO extremes may increase oil toxicity.
Ottway (1970)
Blumer et al.
(1971)
Mironov (1969)
NAS (1975)
NAS (1975)
p. 86
References are on following page.
-------
REFERENCES FOR TABLE 6-15
Ottway, S.M. Proceedings, Symposium on the Effects of Oil
Pollution on Littoral Communities, ed. by E.B. Cowell,
Petroleum Institute, London (1970).
Blumer, et al. "A Small Oil Spill." Environment 13(2)
(1971): 2-12.
Mironov, O.G. "Viability of Some Crustacea in Seawater
Polluted with Oil Products." Zool. Zh. 68(1): 1731.
National Academy of Sciences (Ocean Affairs Board, Commission
on Natural Resources), Petroleum in the Marine
Environment: Workshop on Inputs, Fates, and Effects
of Petroleum in the Marine Environment, 1975, p. 85.
-157-
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concentration) n, where n is the percent mortality
observed in the population. For this statistic to
be meaningful, a particular exposure time must be
specified. For example a 96 hr LC50 is the con-
centration of a particular toxic substance which,
after 96 hours of exposure, will cause 50 percent
mortality in a population of a particular organism.
96 hr LC50 is a fairly common parameter of pollutant
toxicity. It is also frequently referred to as the
TL50 (toxic level 50), or TLm (mean toxic level).
3. Threshold measures -- The concept behind a thres-
hold measure is that populations of an organism
will display essentially zero mortality (no matter
how large the population) below a particular level
of exposure. Such a level is known as a threshold
level, or, sometimes, an incipient lethal level.
Current policy towards regulating water pollutants
for the protection of aquatic and marine life, in
which maximum permissible levels of pollutant
concentrations (standards and criteria) are set,
draws upon this threshold concept, and indeed
there is much evidence for the existence of
thresholds for particular organisms and particular
pollutants. Sprague, for example, in an article
on the toxicity of copper and zinc to young
Atlantic salmon16 notes that "the relationship
between concentration of metal and survival time
could be fitted by a straight line when logarithms
were used. A sharp break in this relation marked
the incipient lethal level, where survival becomes
indefinitely long. Incipient lethal levels were
48 ug/1 (ppb) of copper and 600 yg/1 of zinc."
(see Figure 6-3). In terms of the two parameters
described above, the threshold level could be
expressed as the LCO for a particular time of
exposure, or else as the concentration at which
the LTO becomes infinite (the latter was the
definition used by Sprague in the reference cited
above).
Of course, either of these measurements could be
extended to effects other than lethality. In this case, the
parameters are expressed as the (e.g.) EC50 or ET50, for
effective concentration 50 and effective time 50, respec-
tively.
J.B. Sprague, "Lethal Concentration of Copper and Zinc
for Young Atlantic Salmon," Journal of the Fisheries Research
Board of Canada 21(1) (1964): 17-26.
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0.01'
CONCENTRATION OF METAL,(mg/1)
0.1 LO
200
100
O
X
O
o
in
O
E-i
U
50
20
EH 10
Copper
Zinc
10
I i i
i i i I
20
50
100 300
1000
5000
CONCENTRATION OF METAL, (yg/1)
10
t/5
>H
<=c
D
>H
EH
O
O
LD
O
EH
Figure 6-3. Median mortality-times of young Atlantic
salmon exposed to solutions of copper and zinc. Vertical
bars indicate 95 per cent confidence limits. The straight
lines fitted to the points break and run parallel to the
time-axis at the incipient lethal levels. The experimental
water had a total hardiness of 20 mg/1 as CaC02 temperature
of 15° C and pH 7.1 to 7.5 except for two zinc tests in-
dicated by black squares. These were at 17° and somewhat
different pH values.
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If threshold levels can be shown to exist for marine
organisms (and a wide number of the studies reviewed for
this report suggest that they do for particular pollutants
and organisms), then they can be used as a basis for setting
"safe levels" for the release of trace metal pollutants into
seawater. It is therefore important to develop procedures
for estimating threshold levels on the basis of available
data.
Sprague notes:
"Safe" level is used here in an admittedly loose way,
to mean the concentration of pollutant which does not
have an adverse sublethal or chronic effect on fish.
It is not an entirely satisfactory term since it often
implies more safety than actually exists, but other
descriptive terms do not seem to have gained any wide
acceptance. As used here, a safe level is a statistic,
whose value is empirically determined as a result of an
experiment. Its value is not assigned on the basis of
judgment. If a probable safe level is inferred on the
basis of incomplete information, it should be clearly
labelled as probable or tentative. A safe level may be
specified as referring to one particular life process
such as reproduction, or to the absence of any and all
observable effects. [One way of approximating the safe
level would be to measure in a bioassay system] the
median effective concentration (EC50), i.e., the con-
centration which just causes the selected response in
50 percent of the individuals...Following such practice,
concentrations affecting a negligibly small percentage
of individuals, such as the EC5 or EC1, could be esti-
mated with a known degree of accuracy, by conventional
log probit analysis.1° This has seldom been done in
See the data reviewed in J.B. Sprague, "Measurement of
Pollutant Toxicity to Fish," p. 257.
18
A probit distribution is the dose response relation
expected in a population which exhibits normally distributed
toxicity thresholds to a particular substance. For a par-
ticular level x of a toxic substance in water, the number of
organisms affected will be all those with thresholds less
than or equal to x, which is estimated, using the probit
model, as the integral of the normal distribution for all
concentrations below x. This model defines a relationship
between level of exposure and percent mortality involving
two undetermined parameters, whose value can be estimated by
fitting experimental LCn data. Given values of these para-
meters, a dose/response curve is completely defined, so that
estimates can be made of the dosage levels which would cause
insignificant levels of mortality, e.g., the LCI or LC5.
-160-
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research on sublethal effects even when it might be
advantageous; most investigators have attempted to
estimate (directly)... the safe level. Sometimes such
a "no-effect" concentration cannot be measured pre-
cisely. The parallel idea in lethal tests, of esti-
mating the "minimum lethal concentration" has been
abandoned in favor of the median lethal concentration.
Sprague here refers to two different methods for
determining safe exposure levels: direct experimental
determination of levels at which no effects are observed at
statistically significant levels of incidence (a generally
unreliable procedure) , and the extrapolation of available
ECn data (using probit or other models) to estimate ECls or
EC5s.
More conventionally, threshold levels are estimated
using numbers called application factors. Sprague's review
cites the work of Hart, who attempted to develop "an arith-
metic method of extrapolating along the toxicity curve to
the incipient LC50, with the ratios of different LCSOs
(e.g., the 96, 48, and 24 hr LC50s) simulating the slope of
the curve... A basic feature of (their paper) is that they
estimate the 'presumably harmless concentration1 as essen-
tially 0.3 of the incipient LC50. Indeed, Hart and col-
leagues recommend exactly that simple calculation when the
incipient LC50 is known." This factor of 0.3 is known as an
application factor, and its purpose is to estimate safe or
threshold levels when only median or other toxicological
measures are known. Although application factors can be
grounded in and confirmed by experimental results, or
derived from models using probit or other assumptions, they
are most generally derived from general considerations and
the experience of professional toxicologists. The estimation
of applications factors for toxic substances for aquatic
organisms has mostly been done for freshwater species, and
the values used have ranged from 0.1 to 0.4 (to prevent
lethality), or from 0.01 to 0.05 (to prevent chronic, sub-
lethal and cumulative toxicity). The 1973 EPA Water Quality
Criteria for marine life recommended for most metals an
application factor of 0.01 of the 96 hr LC50 for the most
sensitive resident species, and this is the factor which
should probably be used in evaluating the data presented in
the tables. This application factor, applied to the median
lethal level, was considered by the EPA to provide a margin
of safety in preventing all significant toxic effects.
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6.3.5 Adaptation Responses
It is reasonable to suppose that under conditions of
environmental stress due to high levels of a toxic metal, a
process of natural selection would favor a metal-resistant
subpopulation of a particular species. Thus, relatively
metal resistant organisms, having a relatively high LC50 or
threshold level for the metal, would be found in chronically
polluted waters, diminishing the toxic response to further
pollution. This can be a significant factor in evaluating
toxicity data, and in fact, it has been verified experimen-
tally for the copper response of the estuarine polychaete
Nereis. Bryan and Hummerstone-^ have noted that Nereis
removed from an estuary with extremely high copper levels
due to persistent industrial pollution exhibited a much
higher LT50 at a particular copper concentration than did
Nereis extracted from a relatively clean estuary.
6.3.6 Synergisms and Antagonisms
The interactions between two toxic substances can
either be additive (i.e., the effect of exposing an organism
to a concentration of one metal and another concentration of
a second metal is the sum of the effects noted if the organ-
isms are exposed to the same levels of each metal separately),
synergistic (i.e., supra-additive), or antagonistic sub-
additive) . The literature on whether synergisms exist
between toxicants is confusing and often contradictory; at a
minimum, it would seem that the presence of synergisms is
dependent upon the substances and species involved, and upon
the levels of exposure. The degree of synergism is sometimes
quantified by use of the toxic units concept. A toxic unit
is defined as the concentration of a metal necessary to
produce a well-defined effect (generally, the LC50 concen-
tration for a particular exposure time is used); all concen-
trations of the meta-1 can then be expressed as some fraction
or multiple of this LC50. Now suppose an organism is exposed
to 0.5 toxic units of copper and x toxic units of zinc,
where x is variable. The interaction between the two metals
is additive if 50 percent mortality is observed at the point
when x = 0.5 toxic units (i.e., the sum of the concentrations
19
Bryan and Hummerstone, "Adaptation of the Polychaete
Nereis diversicolor to Estuarine Sediments Containing High
Concentrations of Heavy Metals," Journal of the Marine Bio-
logical Association of the United Kingdom 51 (1971): 845-863.
-162-
-------
of Zn and Cu is 1.0 toxic units), synergistic if 50 percent
mortality is observed for x less than 0.5 toxic units, and
antagonistic if 50 percent mortality is observed only when x
becomes greater than 0.5 toxic units.
Some of the results of recent studies which bear on the
synergistic or additive effects of trace metals on marine
organisms are summarized below:
20
1. According to Sprague, "In solutions containing
both copper and zinc, fish died twice as fast as
would occur if the two metals were simply additive
in their lethal action" (see Figure 6-4).
21
2. Sprague and Ramsay found an additive relationship
between the toxicants copper and zinc in the
vicinity of one toxic unit, but supra-additive
relationships in the range two to five toxic
units. Test organism: juvenile Atlantic salmon.
22
3. Barnes and Stanbury found a synergistic interaction
between the metals copper and mercury for the
marine copepod Nitocra; for example 0.026 mg/1 of
copper produced zero percent mortality; the combi-
nation, however, produced 9.1 percent mortality
(complete data are given in Table 6-16).
20
Sprague, "Lethal Concentrations of Copper and Zinc for
Young Atlantic Salmon."
21
Sprague and Ramsay, "Lethal Levels of Mixed Copper-
Zinc Solutions for Juvenile Salmon."
22
C. Barnes and Stanbury, "The Toxic Action of Copper and
Mercury Salts Both Separately and When Mixed on the Harp-
acticid copepod Nitocra," Journal of Experimental Biology
25(3) (1948): 270-275.
-163-
-------
200
100
D
§ 50
1 20
<*>
o
in
10
Copper
- Zinc
Mixtures
\
10
w
d
ff:
O
O
in
Eu
I
r
0.1 0-5 1.0 3.0 10.0
METAL, FRACTION OF INCIPIENT LETHAL LEVEL
Figure 6-4. Comparison of median mortality-times of
young Atlantic salmon exposed to solutions of copper, zinc,
anC. raixtures. Concentrations are expressed as fractions of
the incipient lethal levels, those for copper and zinc
being added together for the 2 experiments with mixtures.
-164-
-------
TABLE 6-16
EFFECT OF MERCURY AND COPPER ON THE
MARINE COPEPOD NITOCRA (PERCENT MORTALITY)
Cu CONC
Mg/1
0
0.026
0.26
2.6
26
0 0.07
0 0
1.3 9.1
11.3 11.9
21.2 --a
42.5
H CONC
0.15 0.31 0.40
1.4 10.0 16.7
14.5 12.7 50.0
20 45.6 43.7
78 82 98
— __ __
Mg/1
0.60 0.70
50 72
61.8 76.4
100 100
100 100
--
1.5
78
87.3
100
100
—
3.0
84
100
100
100
--
4,4
100
100
100
100
--
a
— means not available.
23
4. Eisler and Gardner found a synergistic interaction
between zinc, copper and cadmium for the estuarine
mummichog (Fundulus heteroclitus). Sample data:
60 ppm of zinc alone produced 27 percent mortality
in 96 hours and 10 ppm of cadmium alone produced
about 4 percent mortality in 96 hours; the combina-
tion of the two, however, produced 60 percent
mortality in the same time period.
74
5. Corner and Sparrow found evidence of synergistic
interaction between copper and mercury (see Figure 6-5)
23
Eisler and Gardner, "Acute Toxicology to an Estuarine
Teleost of Mixtures of Heavy Metals," Journal of Fishery
Biology 5 (1972): 131-142.
24
Corner and Sparrow, "The Modes of Action of Toxic
Agents, I. Observations on the Poisoning of Certain Crus-
taceans by Copper and Mercury," Journal of the Marine Bio-
logical Association of the United Kingdom 35 (1956): 531-548,
-165-
-------
30 ,_
28
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I 1
600
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I t
800
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t 1
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CONCENTRATION (rag metal ion/1.)
Figure 6-5. Effects of bipartite mixtures of equitoxic concentrations
of copper sodium citrate and mercuric chloride (A), mercuric iodide (s) , and
ethylmercuric (c) on the survival of Artemia larvae in seawater (LT50), curves
obtained experimentally; , theoretical curves expected if toxic effects
of the mixed poisons were exactly additive). Concentrations of the metal
ion measured as follows: Cuas citrate (upper row, 0...1,000), Hg++ as
HgCl2 (lower row, 50...0).
-------
25
6. Ventilla found evidence for a synergistic effect
on the growth rate of the marine protozoon Cristigera
of the trace metals mercury, lead and zinc. The
data are given below.
TABLE 6-17
EFFECTS OF MERCURY, LEAD AND ZINC ON THE
GROWTH RATE OF CRISTIGERA
REDUCTION IN
CONCENTRATION GROWTH RATE
(ppm) SUBSTANCE (Percent)
0.005
0.3
0.25
HgCl2
Pb(N03)2
ZnS04
12
12
13
(All three above, combined
at the same concentrations) 67
Much more data are available, but the above references
adequately demonstrate that synergistic interactions between
trace metals can be significant in some systems.
9 f\
Livingston includes an interesting discussion on the
mechanistic rationales for additive, supra-additive, and
antagonistic effects.
25
Ventilla and J.S. Gray, "Growth Rates of a Sediment-
Living Marine Protozoan as a Toxicity Indicator for Heavy
Metals," Ambio 2(4) (1973): 118-121.
9 f\
American Petroleum Institute, U.S. Environmental
Protection Agency, and Marine Technology Society, "Marine
Bioassays: Workshop Proceedings" (Washington, D.C.: Marine
Technology Society, 1974) pp. 245-253.
-167-
-------
6.3.7 Interactions Between Metals and Other Stressors
The presence of other environmental stressors, e.g.,
abnormal salt concentrations, abnormal temperatures as a
result of thermal discharges, or abnormally low dissolved
oxygen can increase the toxicity of brine pollutants.
According to Vernberg and Vernberg:^'
At optimum conditions of salinity and temperature
(30 ppt, 25° C) fiddler crabs live almost indefinitely
in seawater containing sublethal concentrations of
mercury (0.18 ppm). They can also survive prolonged
periods of time in low salinity water and high tempera-
ture (5 ppt, 35° C), but under the latter conditions
the addition of sublethal concentrations of mercury
resulted in an LD50 of 26 days for females and 17 days
for males.
Although relatively little data are available in this
area, it is an important field for further research.
6.3.8 Note on Cyanide Toxicity
Sufficient data on the toxicity of cyanide to marine
organisms was not available to enable a meaningful "safe"
level for this toxicant to be set. Thus, the approach adopted
in the 1975 Water Quality Criteria was used, in which it was
stated:
The effects of cyanide on marine life have not been
investigated adequately to determine separate water
quality criteria, but based on the physiological
mechanisms of cyanide, toxicity to marine life
probably is similar to that of freshwater life. Since
marine waters generally are alkaline, the toxicity of
cyanide should be less than in freshwaters where pH
fluctuations occur more readily and frequently. Thus,
an additional safety factor exists to provide a margin
of safety and compensation for a lack of specific data
on which to base the criterion for marine aquatic life.
Therefore, as a tentative safe level the EPA criterion of
0.005 mg/1 is adopted.
27
F.J. Vernberg and W. Vernberg, Environmental Physiology
of Marine Animals (New York: Springer-Verlag, 1972), p. 331.
-160-
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6.4 Effects of Salinity
The natural salinity of seawater averages about 30 to
35 0/00 (parts per thousand). In the open sea this salinity
is remarkably constant, although it may decrease by as much
as a factor of ten in estuarine areas following heavy rain-
falls, and increase by a factor of three or more in areas
such as lagoons and tide pools where evaporation is important.
The salinity of oilfield brines is comparatively very high;
Mackin, for example, reports that Lousiiana brines have
salinities as high as 128 and 131 0/00.28 j_t is reasonable
to suppose that exposure of resident organisms to these
abnormally high salinities would represent a severe environ-
mental stress which could either produce direct lethal or
sublethal effects or else decrease the resistance of the
organisms to other environmental stressors such as temperature
and trace metal pollution. Unfortunately, the overwhelming
proportion of the literature on salinity stress (as reviewed
by Vernberg and Vernberg29 and others) deals with pathological
effects of low salinities on marine or estuarine organisms
(this is because salinity fluctuations downward from 30 0/00
are common in estuaries, where factors such as wind and
temperature gradients can cause wide variations in the
magnitude and spatial extent of seawater dilution due to the
incoming river water. Low salinities have generally been
considered, therefore, to be of greater environmental
interest than high salinity situations). A number of papers
have presented data from field studies on the effects of
highly saline oilfield brines on local ecosystems, but these
are of little use in estimating toxic effects of salinity
alone because of the complicating presence of hydrocarbon
and trace metal pollution in the brines.
The salinity of the brines would represent an extremely
unsuitable environment for the internal operation of most
marine organisms; so if they are to survive in the vicinity
of these high salinities, they must be equipped with special
osmoregulatory (e.g., active transport) systems to regulate
their internal ion balance in the face of a tremendous
Q. Mackin, A Review of Significant Papers on Effects
of Oil Spills and Oilfield Brine Discharges on Marine Biotic
Communities (College Station, Texas: Texas A&M Research
Foundation, Project No. 737, February 1973), pp. 4-8.
29
Vernberg and Vernberg, Environmental Physiology of
Marine Animals, pp. 167-175.
-169-
-------
salinity difference between their external environment and
internal body fluids. Organisms which can maintain a
constant internal environment independent of external salin-
ity stress are known as osmoregulators, as opposed to
osmoconformers, whose internal ion composition resembles
that of their external medium. Another distinction commonly
made is between euryhalinic species, which are capable of
surviving in a wide range of salinities, and stenohalinic
ones, which can only tolerate a rather narrow range of
salinities. The two sets of terms are not equivalent;
organisms can be partially osmoconforming and yet euryhalinic
Extreme osmotic stress may seriously weaken an organism and
decrease its resistance to other environmental factors; or
it may even saturate the organisms' osmoregulatory capabili-
ties and eventually kill it.
Some quantitative data on the effect of high saline
stress on organisms are summarized below.
1. Davis notes that "Colonies of the polyp Cordylo-
hora caspia, grown from planulae, developed
gonophores only in salinities between 5 and
16.7 ppt, but when normal colonies were amputated
and allowed to regenerate, gonophores were formed
at a wide range of salinities though not in fresh
water nor in salinities higher than 30 ppt."
Davis also states that the development of the eggs
of the pupfish Cyprinodon macularius is inhibited
at both the high and low extremes of salinity (up
to about 85 ppt).
2. Figures 6-6 and 6-7, respectively, show the effect
of salinity on the survival of adult fiddler crabs
and the survival of Sesarma cinereum zoae under
thermal stress.
3. Vernberg and Vernberg note: "Some animals can
even survive extremely hypersaline conditions in
tidal pools cut off from ocean waters. For
example, fiddler crabs, Uca rapax, are commonly
found living on the salt flats of Puerto Rico in
salinities as high as 90 0/00. The strong ability
to hyporegulate is evident in two species of
crabs, Pacygrapsus crassipes and Hemigrapsus
oregonesis, which are known to thrive in a hyper-
saline lagoon (66 0/00) cut off from the sea.
Vernberg and Vernberg, Environmental Physiology of
Marine Animals, p. 70.
-170-
-------
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Figure 6-7. Survival of larval tropical and
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-172-
-------
Some species of intertidal zone fish that inhabit
protective rocky shores show remarkable tolerance
to high salinities. Along the Texas coast where
salinities in tide pools may reach very high
levels, fish have been found living in salinities
as high as 142.4 0/00."
Unfortunately, there do not seem to be enough quantita-
tive data to support the type of analysis which is being
performed for metals and oils. Salinity related effects
will generally be ignored in this analysis, therefore. This
may seem rather arbitrary, but that the assumption is not
too severe is suggested by some of the data of Mackin,31
and by our dispersion model ouputs which show relatively
rapid dilution of salinity within very small distances from
offshore drilling rigs in Louisiana.
6.5 Studies of Brine Toxicity and of the Effects of Brine
Discharges at Offshore Production Sites
A key deficiency in the use of laboratory bioassay data
in the prediction of on-site tcxicity of oilfield brine com-
ponents is that laboratory experiments are performed, almost
by definition, under a single, highly controlled set of
conditions. Although bioassay experiments always attempt to
duplicate, to the extent possible, the conditions prevailing
in the natural environment, it is impossible to capture in a
laboratory system the multitude of highly variable physical,
chemical and biological parameters which characterize actual
oilfield sites. The issue was concisely stated by Mackin:32
"The dream of developing a short-term laboratory study which
would enable us to predict effects on natural communities of
various pollutants is just that: a dream." For these
reasons, field studies form an important complement to
laboratory bioassay data.
Several studies have been performed on the ecology of
oilfield production areas. Unfortunately, little, if any
information is given in these studies regarding the rate of
Mackin, Review of Effects of Oil Spills on Marine
Biotic Communities.
32
Mackin, Review of Effects of Oil Spills on Marine
Biotic Communities.
-173-
-------
brine discharge at the study site so that it is difficult to
evaluate the findings. The Gulf Universities Research
Consortium (GURC) study on the ecology of oilfield areas
is not germane to the objectives of the report since the
production platforms studied were either not dischargers
of brine or discharged brine only intermittently and in
small quantities. Mackin has suggested a number of general-
izations which can be drawn from field study data.
1. The key factor controlling the effects of oilfield
brines on resident communities seems to be con-
centration. Dilution of the brines is extremely
rapid, and reduction of the brines to apparently
harmless levels seems to take place due to dilu-
tion before other environmental processes (e.g.,
degradation) have a chance to operate to any
significant degree. According to Mackin, "The
dilution in large waterbodies and comparatively
deep water is almost instantaneous, and dilutions
of 1,000 parts of seawater to one part of brine
can be effected in even comparatively shallow
water in distances of from 8 to 50 feet."
2. The area in the vicinity of an oilfield brine
discharge can be divided into concentric "zones of
effect," with successively less severe effects
being observed in zones farther and farther from
the discharge point. Mackin identified three
zones: an inner zone in which all benthic organ-
isms, except perhaps bacteria, are destroyed; a
transition zone in which depression of both
benthic species numbers andL numbers of individuals
is observed; and an outer "stimulation zone" in
which productivity is actually increased over that
distance from the discharge. The explanation for
this stimulatory effect seems to be in the use of
petroleum hydrocarbons as a nutrient source by
bacteria, yeasts, fungi, and other phytoplanktonic
organisms. The resulting rise in the phytoplankton
populations stimulates those populations which
feed on the phytoplankton. The role of petroleum
as a toxicant in zones one and two but as a
nutrient in zone three emphasizes again the impor-
tance of concentration and dilution in determining
toxic effects of brine discharges.
3. Mobile organisms (e.g., fish) do not remain in
zones one and two long enough to be effected, so
the primary effect is confined to the largely
sessile benthic organisms. Of course, indirect
-174-
-------
ecological effects may result in nonbenthic
populations as a result of the modification of the
benthic communities.
Mackin cites a number of studies in his review to
support this general model of oilfield brine toxicity. He
discusses the studies of Lunz and others^ on the toxicity of
oilfield brines in bioassay systems to show that beyond a
certain level of dilution no toxic effect is observed (note
that by using the brine in a bioassay system, rather than
its individual components, synergistic and antagonistic
interactions are automatically taken into account). In one
study of the toxicity of brines to Palaeomonetis pugio, the
most toxic of the brines studied produced a 48 hr LC50 of
about 200,000 ppm to the most sensitive of the organisms
studied. The least toxic brine had an LC 50 of about
1,000,000 ppm; i.e., a 100 percent brine solution would only
kill 50 percent of the £_._ pugio individuals within 48 hours.
The use of an application factor of .01 together with the
"worst case" LC50 gives an estimated "safe" concentration of
about 2,000 ppm (corresponding to a dilution of one part of
brine to 500 parts of normal seawater). In another study
Lunz34 showed that Louisiana brines (salinity 128 ppt) had no
effect on the pumping rates of oysters at bioassay concen-
trations of from 10,000 to 50,000 ppm (1 to 5 percent). A
threshold of about 3 percent was observed for any effect on
the ability of oysters to clear a turbid medium. ^
Mackin, Review of Effects of Oil Spills on Marine
Biotic Communities.
34
G.R. Lunz, The Effect of Bleedwater and of Water
Extracts of Crude Oil on the Pumping Rate of Oysters,
(College Station,Texas:Texas A&M Research Foundation,
Project No. 9, 1950).
E.J. Lund, "Effect of Bleedwater, Soluble Fraction,
and Crude Oil on the Oyster," Publications of the Institute
of Marine Science 4(2) (1957): 321-341.
-175-
-------
Data collected by Menzel and Hopkins seemed to confirm
the existence of "zones of influence." These investigations
were conducted in the Lake Barre Field (Texaco) in Louisiana,
and showed heavy oyster mortality within about 25 feet of
the drill platform, a zone of lesser mortality extending out
to 75 feet from the platform, a zone of stunted growth
extending out to about 150 feet from the platform, and no
effect, except possibly some stimulation, beyond 150 feet.
The stimulation effect was described as "weakly significant."
The data for this field is shown in Figure 6-8. Note that
toxic effects seemed to disapoear beyond about 200 feet from
the platform, so that the effects were rather local.
A similar study conducted by Mackin in 1971 also
showed zones of effect. Zone one (as defined above) ex-
tended out to about 50 feet from the rig; zone two extended
from about 150 to 200 feet; and zone three reached from 400
out to several thousand feet from the rig. This study
involved an intensive program of biological characterization
of the areas around six oil fields in Texas. The principal
conclusions were that no effect was observed outside of a
purely local one, and that the local effect was concentrated
primarily on benthic organisms, with the more motile popula-
tions being totally unaffected. The indices of effect
studies included number of species/station, number of
individuals/sample, taxon diversity, species diversity, and
reproductive capacity. Among the conclusions of this study
were:
1. Exposed organisms exhibited a wide range of
tolerances to the toxic effects of brines. The
least sensitive were the polychaetes (this is
consistent with a recent study of the adaptation
R.W. Menzel, Report on Oyster Studies in Caillou
Island Oil Field, Terrebonne Parish, Lousiana (Texas:
Texas A&M Research Foundation, Project No. 9, 1950); R.W.
Menzel and S.H. Hopkins, Report on Experiments to Test the
Effect of Oil Well Brine or Bleedwater on Oysters at Lake
Barre Oilfield (Texas: Texas A&M Research Foundation, Project
No. 9, 1951); and R.W. Menzel and S.H. Hopkins, Report on
Oyster Experiments at Bay St. Elaine Oilfield (Texas: Texas
A&M Research Foundation, Project No. 9, 1953).
37J.G. Mackin, A Study of the Effect of Oilfield Brine
Effluents on Biotic Communities in Texas Estuaries (Texas:
Texas A&M Research Foundation, Project No. 735, November
1971).
-176-
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of the polychaete Nereis to high copper concentra-
tions in an English estuary38)r followed by the
molluscs, follosed by the Crustacea, which seemed
to be the Mysicacea, the Tanaids, the grass shrimp,
the amphipods, and the isopods.
2. The picture of an effect confined to a local inner
zone of effect seems to be confirmed. Figure 6-9
shows typical data from the Trinity Bay field
stations. Here, station 1 was located at about 50
to 75 feet from the rig; station 2 at 250 to
300 feet from the rig; station 3 at 500 to 550
from the rig; station 4 at 1,100 feet from the
rig; and stations 5 through 12 equally spaced out
to a final distance of about 2.5 miles.
3. "...All bottom invertebrates are sensitive to
brine effluent if the concentration is sufficient
and none are susceptible provided sufficient
dilution and chemical and biological degradation
occurs. In the Trinity Bay field there can hardly
be any doubt...that there is a healthy, vigorous
reproductive community in existence over the major
area of the field."
4. "...In summary, the brine discharge showed an
effect on bottom fauna in Trinity Bay field at
Stations 1 and 2. The effect ended somewhere
between Station 2 (300 feet from the brine dis-
charge) and Station 3 (500 feet from the brine
discharge)...and the area affected is approxi-
mately 0.015 percent of the total bay."
A somewhat less cheerful picture is presented by a
number of studies conducted by the Texas Parks and Wildlife
Department3^ on oil drilling operations in Chiltipin Creek
in Louisiana. The report produced a variety of evidence to
show that Chiltipin Creek was "nearly devoid of marine life"
3 8
Bryan and Hummerstone, "Adaptation of the Polychaete
Nereis diversicolor."
39
R.W. Spears, An Evaluation of the Effects of Oil,
Oilfield Brine and Oil Removing Compounds, Environmental
Quality Conference for the Extractive Industries of the
American Institute of Mining, Metallurgical, and Petroleum
Engineers, Inc., June 1971.
-178-
-------
W
^
ft.
CO
\
CO
W
H
U
W
ft,
CO
W
m
s
D
W
s;
-20
16
- 12
- 8
_ 4
Mean: Stations 1-12 13.9
Mean: Stations 3-12 15.2
5678
STATIONS - NOT TO SCALE
10
11
12
Figure 6-9. Trinity Field, Trinity Bay - Number of species in relation to
the brine discharge at F]_ platform bottom samples. Each point is the mean of
12 monthly samples.
-------
compared with nearby streams, unaffected by oil drilling
operations, which had relatively rich populations of various
organisms. Here relatively large amounts of brine were
being produced and discharged into a relatively small
receiving waterbody, producing highly toxic environments for
marine life. (This contrasts with the situation observed in
the areas studied by Mackin in which the receiving waterbody
was a large bay.) Studies of the Chiltipin Creek area
revealed that the production of two commercially important
species (the white shrimp, Penaeus setiferus and the blue
crab, Callinectes sapidus) were drastically reduced in
Chiltipin Creek compared to neighboring tributaries. The
effect seemed to be correlated with periods of low rainfall,
and chemical investigation showed high concentrations of oil
(above those specified by the Texas Water Quality Standards)
in the Creek. This provided power evidence for a brine-
related effect on the communities of the Creek.
4 0
A study conducted by Heffernan under the auspices of
the Chiltipin Creek project provided valuable data on the
toxicity of brine. These data are summarized in Table 6-18.
The bioassay test period in these figures was 48 hours.
Another important study of the effects of oilfield
brines was conducted by Mackin and Hopkins in 1961 on
Louisiana oilfields. The study was an attempt to trace the
effects of brine discharges on the ecological communities of
the study area, and involved consideration of a variety of
historical, toxicological and environmental monitoring data.
Four important conclusions of the study were as follows:41
1. The history of the oyster industry shows that
Louisiana oysters have always been subject to high
rates of mortality, and that periods of disas-
trously high mortality have been frequent as far
back as the records go.
40
T.L. Heffernan, J. Monier, and S. Page, Effects of
Oilfield Brine on Marine Organisms. An Ecological Evaluation
of the Aransas Bay Area, Job No. 1, Texas Parks and Wild-
life Department (1972).
41
J.G. Mackin and S.H. Hopkins, "Studies on Oyster
Mortality in Relation to Natural Environments and to Oil
Fields in Louisiana," Publications of the Institute of
Marine Science 7 (1962): 1-131.
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TABLE 6-18
BIOASSAY DATA ON OILFIELD BRINES
FROM CHILTIPIN CREEK AREA (TEXAS)
TEST ORGANISM FACILITY
Brown shrimp Haas Ditch 24.5 - 26.5
White shrimp Haas Ditch 28.0
Brown Shrimp Southwestern i Q n _ -M c
Oil L U
White Shrimp Southwestern , ., _
Oil 1J'b
Blue Crab Southwestern 9, n
Oil ^x'u
2. The study of Louisiana oyster production statis-
tics and oyster history showed that disastrously
high mortality of oysters had occurred at times
both before and after oil production began in the
oyster-growing area, and that since oil production
started there had been oyster mortalities in
places far distant from oil operations as well as
in and near oilfields.
3. Field studies of Texas A&M Research Foundation
biologists, beginning in 1947, confirmed reports
that mortality rates were high on many Louisiana
oyster beds, and that there was a seasonal cycle
-181-
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in mortality correlated with temperature. Except
during abnormally warm periods there was little
mortality in winter, but oysters began to die in
spring and continued to die steadily all summer
and into autumn until stopped by cool weather.
The regular and predictable nature of this mortal-
ity indicated that it was not abnormal. The
general picture was, rather, that a high rate of
mortality associated with summer temperatures was
normal in much of the Louisiana oyster-growing
territory.
t
4. Field studies of Foundation biologists also showed
that within the region where damage from oil
operations was claimed (in general, Placquemines,
Jefferson, Lafourche, and Terrebonee Parishes)
there were areas where oyster mortality was con-
sistently low as well as areas of high mortality.
No correlation was found between rates of mortal-
ity of oysters and their proximity to oilfields.
Indeed, in the Barataria Bay area where most
damage to oyster production was claimed, the
highest mortalities were found at the stations
farthest from centers of oil and bleedwater
production. On the other hand, high mortality was
found to be correlated with high salinity of the
water.
This suggests that wide natural variations in mortality
can frequently swamp any effects due to oilfield brines.
One further important conclusion of the study was that
"crude oil and fractions of crude oil are rapidly oxidized
and destroyed by bacteria which live in Louisiana bay muds."
6.6 Human Health Risks Associated with Oilfield Brines
Previous sections in this chapter have concentrated on
the risk to fish, plankton, and benthic populations produced
by oilfield brines. This section will consider the human
health risks created by the concentration of potentially
carcinogenic or otherwise toxic brine components in marine
organisms which may be subsequently consumed by human beings.
Two factors must be taken into account here: first, the
rate at which these toxic substances are accumulated in
individual organisms (bioaccumulation) and through the food
chain (biomagnification); and secondly, the potential effects
of these substances on human beings. Two cases in particular
have attracted much attention in the technical literature:
the problem of biological methylation of mercury in the
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marine environment followed by bioaccumulation of the methyl
mercury thus formed by shellfish destined for human consump-
tion; and the problem of contamination of fish and shellfish
with potential petroleum carcinogens such as benz[a]pyrene.
First, background data on the bioaccumulation of trace
metals and hydrocarbons will be reviewed, and then these two
potential human health problems will be discussed.
6.6.1 Bioaccumulation of Trace Metals
Cadmium
The normal concentration of cadmium in seawater is 0.11
parts per billion (ppb). Fleischer^ has reported concentra-
tion factors for a variety of organisms. Concentration
factors for zooplankton and jellyfish are 13,000 and 11,000
respectively. Most invertebrates show factors of from 1,000
to 10,000. Concentration factors in fish are generally less
than 100. Accumulation is often greater in gills and visceral
organs, as demonstrated by experiments on Chasmycthus gulosus
and Venerupis philippinarum.43
Chromium
Chromium is found in seawater at 0.05 ppb. Many marine
organisms are capable of concentrating chromium by a factor
of several thousand. Concentration factors on the order of
10,000 have been observed in Crassostrea Virginica (American
oyster), Mya arenaria (softshell clam), and Mercenaria
42
M. Fleischer, A.F. Sarofim, D.W. Fassett et al.,
"Environmental Impact of Cadmium: A Review by the Panel on
Hazardous Trace Substances," in Environmental Health Per-
spectives, May 1974, pp. 253-323.
43
U.S. Environmental Protection Agency, Environmental
Studies Board, Water Quality Criteria 1972, Washington, D.C,
1972.
-183-
-------
44 45
mercenaria (quahaug). Merlini reports chromium levels
400,000 times those in the ambient environment in the testes
of the sea urchin Tripneustis esculenta. High concentra-
tions have also been found in the gills and gonads of the
mummichog.^°
Copper
The concentration of copper in seawater is 3 ppb.
Raymond^' found copper accumulations in the gut and body wall
of the worm Neresi virens. Copper uptake is temperature
dependent, the rate roughly doubles with a 10° C increase in
temperature. Uptake is proportional to animal size, and
decreases with time following a peak after 20 hours of
exposure. Seasonal changes influence the uptake of copper
by Busycon canaliculatum, the channeled whelk. Uptake
increases in the early summer with the beginning of the
feeding period, and decreases during the fall and winter
hibernation period. Copper is accumulated through the
gills, where concentration increases to an equilibrium
concentration after about one hour of exposure, when trans-
port away from the gills equals the rate of intake. Copper
is transported from the gills to the digestive gland.
Experiments with Nereis diversicolor, another worm, show
copper concentration to be roughly proportional to concen-
tration in the sediments. ° Worms from sediments of high
44
B. Pringle, D.E. Hissong, E.L. Katz, and S.T. Mulawka,
"Trace Metal Accumulation by Estuarine Mollusks," Journal of
Sanitary Engineering Division (June 1968): 455-475.
45
Margaret Merlini, "Heavy Metal Contamination," in
Impingement of Man on the Oceans, ed. by Donald W. Hood (New
York: Wiley-Intersciences, 1971).
U.S. Environmental Protection Agency, Water Quality
Criteria 1972.
47
J.E.G. Raymond and J. Shields, "Toxicity of Copper and
Chromium in the Marine Environment," in Advances in Water
Pollution Research, Vol. 3, ed. by E.A. Pearson, Proceedings
of the International Conference, London, September 1962
(London: Pergamon Press, 1964) .
48
G.W. Bryan, "Adaptation of an Estuarine Polychaete to
Sediments Containing High Concentrations of Heavy Metals,"
in F.J. Vernberg and W.B. Vernberg, Pollution and Physiology
of Marine Organisms (New York: Academic Press, 1974) .
-184-
-------
copper content apparently have an increased tolerance to
copper. The tolerant worms absorb copper more readily, and
are not affected by copper concentrations toxic to unadapted
polycheates.
Mercury
Mercury's seawater concentration is 0.03 ppb. Concen-
tration factors up to 80,000 have been observed in Crassostrea
virginica (American oyster), with maximum accumulation in
the gills. The highest concentration of mercury in cod
exposed to mercuric nitrate was found in the gills also,
where the concentration factor was 3,760.50
Nickel
Concentration of nickel in seawater is reported to be 2
to 5.4 ppb. Concentration factors in marine organisms range
from 7,000 to 74,000. Concentration factors for mussels, ?-.
scallops and oysters are 14,000, 12,000 and 4,000 respectively.
Lead
Lead is found in seawater at a concentration of 0.03 ppb.
According to Pringle,52 lead concentrations in the gills,
gonads, and liver of Crassostrea virginica are on the order
of 1,000 times the seawater concentration. Concentration
factors in the other tissues are somewhat lower. Whole
organism concentration factors for Crassostrea, Mya arenaria,
and Mercenaria mercenaria are 1,300, 2,300 and 1,700 respectively,
49
Frederic C. Kopfler, "The Accumulation of Organic and
Inorganic Mercury Compounds by the Eastern Oyster (Crasso-
strea virginica)," Bulletin of Environmental Contamination and
Toxicology 2 (1974): 275-280.
U.S. Environmental Protection Agency, Water Quality
Criteria 1972.
Merlini, "Heavy Metal Contamination."
52
Pringle et al., "Trace Metal Accumulation."
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Zinc
Seawater concentration of zinc is 10 ppb. Zinc is
concentrated in the gills and digestive gland of Crassostrea,
and in the gills and kidneys of Cyprinus carpio.53LaminarTa
digitata, a marine plant, accumulates zinc to concentrations
u-p to 1,800 times the ambient concentration. Experiments
with the polycheate Nereis diversicolor show that concentra-
tion factors in the worms vary by a factor of three with a
factor of 30 variation in sediment concentration.54 This
observation implies that the worms have a substantial degree
of regulatory control over zinc accumulation. Worms adapted
to high concentrations are about 30 percent less permeable
to zinc than nonadapted worms, and are probably better able
to excrete it. Therefore, the adapted worms can maintain a
relatively normal zinc concentration and can avoid toxic
effects.
It is readily apparent from the above discussion that
accumulation is a complicated process, affected by a number
of different parameters. Present literature is insufficient
to establish a totally clear understanding of the process.
Much more research, and more importantly, standardized
research, will be needed before a definitive understanding
of accumulation can be developed. Such an understanding
would be useful not only for this study, but also for numer-
ous other analyses of effects of pollutant discharges on
marine ecosystems.
6.6.2 Hydrocarbon Bioaccumulation
Many marine organisms have the capacity to take up and
accumulate hydrocarbons from their environments. This
ability has been demonstrated in mussels, clams, oysters,
crabs, shrimp, sponge, and fish, among other organisms.
Both field and laboratory studies have dealt with the accu-
mulation process. Although the results of these studies are
varied and often inconsistent, they do serve to demonstrate
that the ability to accumulate hydrocarbons is widespread
among marine organisms.
U.S. Environmental Protection Agency, Water Quality
Criteria 1972.
54
Bryan, "Adaptation of an Estuarine Polychaete."
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The mechanism and available data on bioaccumulation of
hydrocarbons by marine organisms are summarized in Appendix F
and will not be discussed in any detail here. For the
purposes of this assessment, our only interest is in the
rate of bioaccumulation of one particular hydrocarbon,
benz[a]pyrene. Unfortunately, long-term bioaccumulation
data are not available, but one excellent short-term
(24-hour) study is available for the clam Rangia cuneata.
Twenty-four hour exposure of this clam to 0.0305 ppm of
benz[a]pyrene resulted in tissue concentrations of 5.2 and
7.2 ppm benz[a]pyrene.55 Accumulation occurred mainly in the
viscera — digestive system, gonads, and heart. Thirty days
depuration left 0.07 ppm of contaminants; after 58 days less
than 0.01 ppm remained.
6.6.3 Hazards of Methylmercury Contamination of Marine
Organisms
An important potential human health hazard is created by
the presence of mercury in oilfield brines. Mercury in the
marine environment can easily find its way into bottom muds
and sediments, where it can be biologically methylated by
anaerobic bacteria (this process is known to occur in the
bottom muds of lakes, and can presumably occur in the marine
environment as well). The products of this methylation are
the methylmercury(I) ion, CH Hg+, and dimethylmercury,
(CH3)2Hg, which is spontaneously converted to CH3Hg+ in low
pH environments.56 Although dimethylmercury is fairly volatile,
the methylmercury ion is water soluble and is bioaccumulated
to a significant extent (bioaccumulation factors on the
order of a few thousand have been reported for a freshwater
fish, the pike). The toxicology of methylmercury has been
well studied, both in animals and in human beings as a
result of events such as occurred in the Japanese city of
Minimata, where significant fractions of the population were
exposed to shellfish contaminated with methylmercury from an
industrial effluent. The compound is easily absorbed through
the gastrointestinal tract, passes easily through placental
and blood/brain barriers, can cause extensive nervous
damage, and is a powerful mutagen.
Jerry M. Neff and Jack W. Anderson, "Accumulation
Release, and Distribution of Benzo[a]pyrene-C in the Clam
Rangia cuneata," in Conference on Prevention and Control of
Oil Pollution, U.S. Environmental Protection Agency, American
Petroleum Institute, U.S. Geological Survey, 1975.
Spears, An Evaluation of the Effects of Oil, Oilfield
Brine and Oil Removing Compounds.
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A number of legal standards have been set up for maximum
permissible levels of mercury compounds in fish destined for
human consumption. These standards are based on consider-
ations of available animal and human exposure data, and are
considered to represent prudent safety factors which will
protect exposed human populations from all significant
neurotoxic, teratogenic, and other effects of methylmercury
poisoning. (For a discussion of the rationale for these
standards, see Skerfving's review of mercury in fish.)57 The
prevailing limit in the U.S. and Canada, promulgated in
1970, is 0.5 ppm of mercury in fish. Assuming a high concen-
tration factor of about 5,000, this translates into a level
of no more than 0.1 ppb in seawater. This, of course, would
only apply to sessile organisms continuously exposed to this
concentration of mercury.
6.6.4 Human Health Impacts of Benz[a]pyrene
Among the organic compounds known to be present in
crude oil is the polynuclear aromatic hydrocarbon benz [a]-
pyrene, a compound which is known to be strongly carcino-
genic in animals. The molecule is hydrophobic, and will
partition preferentially into lipids of marine organisms,
where it can be subject to both bioaccumulation and biomag-
nification effects. Although no data are available on
benz[a]pyrene levels in oilfield brines, its presence in
parent crude oil, together with the fact that oilfield
brines are known to be enriched in the aromatic fractions of
crude oil, makes it highly plausible that it is present in
these brines. Unlike mercury, enough data do not exist for
this compound to predict any reasonable safe level for its
concentration in food. Therefore, an unacceptable level of
benz[a]pyrene was defined as one which, after bioaccumulation,
would not produce a level of BaP in shellfish which would
exceed the minimum background levels of BaP in other food
sources.5° For this purpose a final concentration in food of
1 ppb was defined as unacceptable. It should be emphasized
that this is not to be interpreted as a "safe" level, only
S. Skerfving, "Mercury in Fish — Some Toxicological
Considerations," Food and Cosmetics Toxicology 10 (1972):
545-556.
5 8
For data on levels of BaP in food sources, see National
Academy of Sciences, Committee on Biologic Effects of Atmos-
pheric Pollutants, Particulate Polycyclic Organic Matter,
Chapter 14 (Washington, D.C., 1972), pp. 160-165.
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as an unacceptable level which should not be exceeded. BaP
is a potent carcinogen, and no information is available to
estimate a threshold level or even to suggest that such a
level exists.
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CHAPTER SEVEN
IMPACT ASSESSMENT
7.1 Introduction
In this chapter the data, model outputs, and assessment
methods described earlier in this report will be combined to
estimate the magnitude of brine-related impacts occurring at
the four study sites in Cook Inlet, Hackberry Bay, near
offshore Gulf of Mexico (Grand Isle), and far offshore Gulf
of Mexico. The assessment methods used in this chapter were
discussed in detail in Chapter Six, and are presented in
summary in Figure 7-1.
Briefly, the assessment begins with the definition of a
level for each brine constituent which is safe with respect
to toxic impacts on marine and estuarine organisms. For two
particular brine constituents, mercury and benz[a]pyrene (BaP),
a further set of safe levels, designed to prevent the bio-
accumulation of these substances to undesirable levels in
shellfish or other organisms which might be used for human
consumption, is defined. Each of these safe levels implies
a "necessary dilution factor," that is, a brine dilution
required to bring the particular constituent down to its
safe level. The outputs of the dispersion model, described
in Chapter Five, can then be used to estimate the area in
which any of the constituents is at a concentration greater
than or equal to its safe level. This area is taken as an
estimate of the area of a zone of impact.
An alternative definition of a "safe" degree of brine
dilution was also used to take into account possible inter-
actions between the toxicities of two or more brine con-
stituents. This alternative definition takes into account
the fact that a combination of pollutants each of which is
at or below its individually estimated safe level may itself
be unsafe. Although inadequate data are available to estimate
quantitatively the interactive toxic effects produced by a
complex mixture of pollutants such as oilfield brine, a
necessary dilution factor can be approximated by use of the
following approach.
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Criteria
LC50 Data
Sublethal Effects
Data
Data on Human
Health Effects
Estimation of "Safe"
Concentrations
Bioaccumulation
Data (Hg,BaP)
Levels in Brines
Calculation of Necessary
Dilution Factors
Dispersion Model
Outputs
Determine Dominant
(Longest Range)
Effect
Determine Impacted
Areas(Best,Worst Cases)
Figure 7-1. Outline of the analysis.
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Assume that the toxicity of a combination of different
pollutants is the sum of their respective individual toxicities;
i.e., ignore the possibility of antagonistic or synergistic
interactions. Then, if Cj_ and S^ are respectively the pro-
duced water concentration and safe level of the i.^h pollutant,
the necessary dilution factor for the mixture, (NDF) , is
given by the equation^ °
£ ci/(NDF)tot = 1 Z ^i = i
i=l s.
-------
impacted. Thus, a particular level of brine impacts in a
highly fertile, productive region which supports large
populations of ecologically and economically important
organisms would probably be more significant than an equiva-
lent level of impacts in an area which is naturally infertile
and nonproductive. Unfortunately, it was not possible
within the scope of this project to quantitatively assess
the ecological impacts of the different types of ecosystems
which might be affected by brine discharge.
It should be emphasized that this assessment procedure
only takes direct effects into account, and does not attempt
to analyze subsequent ecological interactions and longer-
range indirect effects resulting from brine toxicity. For
example, although a particular ensemble of brine constituent
concentrations in an area might cause 25 percent mortality
in a population of embryonic oysters, the reproductive
potential of the oyster population may be large enough to
maintain the population at its pre-impact levels. Thus,
although a significant direct effect would be produced (and
would be predicted by this assessment) in the long run the
effect may be relatively insignificant. Conversely, an
ecological system may be poised in a relatively delicate
equilibrium, so that toxic stresses resulting from brine
discharges may produce long-range effects much greater than
any direct toxic impacts which would be estimated by the
analysis described in this report.
Another factor ameliorating brine impacts which cannot
be taken into account in this analysis is the selection,
over the course of several generations, for subpopulations
which are relatively insensitive to the effects of particular
brine constituents. This effect 'has been observed, for
example, in Nereis spp. living in a copper-polluted estuary
(see Section 6.2.5). Later in this chapter we will comment
on the. agreement between predicted impacts and field data,
and on the extent to which the resiliency (or, conversely,
the instability) of the ecosystem seems to modify the pre-
dicted level of toxic impacts.
The assessment methods implemented in this chapter
predict significantly different impacts on the four study
sites considered in this report. This fact illustrates the
importance of such site specific factors as depth and current
velocities in determining the level of brine impacts.
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7.2 Results of the Hackberry Bay Assessment
The impacts analysis described in the previous chapter
will first be applied in detail to Hackberry Bay to illustrate
the form of the analysis and the methods used. The methods
are practically identical for the other three study sites,
so for these only the results will be discussed.
7.2.1 Area/Concentration Relationships
As described in Chapter Five, the brine dispersion
model was used to generate a set of contours of equal brine
dilution (isopleths) for each of the sites being studied. A
typical set of predicted isopleths for the Hackberry Bay
site is shown in Figure 7-2. A number of computer runs were
made for each site, in order to assess the sensitivity of
the results to assumptions relating to current velocities,
diffusion coefficients, and other model input parameters.
For each run, the areas enclosed by each isopleth were
measured by planimetry, and the data were plotted on a
concentration versus included area graph, which shows, for a
particular concentration value, the area of a site over
which concentration is greater than or equal to that value.
Each site therefore generated a set of these area/ concen-
tration curves, one for each set of numerical assumptions
tested. The upper envelope of this sheaf of curves defines
a worst (maximum impacted area) case, and the lower envelope
defines a best case. A base case was also defined using
most probable estimates for the values of each input para-
meter. The calculated best, worst, and base case curves for
the Hackberry Bay site are repeated in Figure 7-3.
Since Hackberry Bay is an enclosed area, it is appro-
priate to apply to it the tidal flushing calculation described
in Chapter Four, Section 4.2. The relationships derived in
that section imply a minimum "background" brine concentration
of about 0.18 percent for Hackberry Bay. Thus, the area/
concentration curves were only extended down as far as
0.1 percent dilution, and 0.18 percent was defined as the
effective minimum brine concentration over the whole bay.
Areas included by higher concentrations can be estimated
from Figure 7-3.
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5000
4000
3000
2000
1000
500
W
w
-soo '
-1000
I I I I I I I
t/f I H7
7///M
•400 600
X
800
1000 1200
1400
-2000
-3000
—«000
-5000
FEET
Figure 7-2.
(Base Case).
Typical set of isopleths for Hackberry Bay site
-196-
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X3000-
;ooc-
CN
±>
«M
§ -I
0.01
H2,H4,H5
H6
H7
BASE CASE HI
H3
HACKBErLRY BAY
0.1 1.0
CONCENTRATION (%)
10.0
Figure 7-3. Plots of area/concentration curves for
sensitivity analyses performed for Hackberry Bay site.
Base Case assumes most probable values of input parameters;
for other cases, input parameters are individually varied
over their range of plausible values.
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7.2.2 Numerical Data Used in Impacts Analysis
Table 7-1 summarizes the assumed values of the numerical
parameters (toxic concentrations, etc.) required for this
impact assessment. In each case the value is stated along
with the source of the data or the rationale for the par-
ticular estimate made.
Since only incomplete data are available on the chemical
composition of Louisiana brines, concentrations of trace
metals in the brines were generally estimated as the mean of
maximum values which had been observed at sites in California,
Alaska and Texas.
Toxicological data are generally derived from the
tables and text of Chapter Six. Since 0.01 application
factors used are meant to be applied to 96 hr LC50 data, a
technique was necessary to extrapolate to the 96 hr values
from the 48 or 24 hr values which were frequently reported
instead. The data from Eisler" on cadmium toxicity were
used to make this estimate. Ninety-six hr LC50 data for
cadmium for a number of marine species were plotted against
48 hr LC50 data for the same species, and a ray through the
origin was best-fitted to the eight available data points.
The points gave a reasonably good fit (correlation coefficient
= 0.86) to the relationship (96 hr LC50) = 0.17(48 hr LC50),
which was subsequently used to estimate the 96 hr figures.
A similar procedure was used to obtain the relationship
(96 hr LC50) = 0.096 (24 hr LC50). Insufficient data were
available to determine whether this relationsip also held
for toxicants other than cadmium.
Mercury safe levels in seafood were based upon the
legal standard currently prevailing in the United States and
Canada. Available toxicological data were totally inadequate
to estimate any sort of a safe level for benz[a]pyrene.
Therefore, an unacceptable level of BaP was defined as one
which, after bioaccumulation, would not produce a level of
BaP in shellfish exceeding the minimum background levels of
R. Eisler, "Cadmium Poisoning in Fundulus heteroclitus
(Pisces: Cyprinodontidae) and Other Marine Organisms,"
Journal of the Fisheries Research Board of Canada 28 (9)
(1971): 1225-1234.
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TABLE 7-1
VALUES OF IMPORTANT NUMERICAL PARAMETERS
PARAMETER
VALUE
RATIONALE
Concentrations of brine
constituents in brines:
Ag
As
Cd
CN
Cr
Cu
Hg
Ni
Pb
Zn
Phenol
0.05 ppm
0.37 ppm
0.28 ppm
0.007 ppm
0.12 ppm
0.19 ppm
0.036 ppm
0.39 ppm
0.30 npm
1.25 ppm
3.5 ppm
See Chapter Three and
comments in
Section 7.2.2.
Concentration of oil
hydrocarbons in brines
50 ppm
Table 3-8 ; maximum
post-treatment
levels for "oil and
grease" in brine.
Concentration of BaP in
crude oil
0.4-1.6
ppm
Data cited in Neff
and Anderson (1975)
Enrichment factor for
aromatics in crude oil
water soluble fraction
(WSF)
14.29
Anderson et al. (1974) .
This value means that
the ratio (aromatics/
other HC's) is 14.29
times as great in crude
oil WSF as in the
original crude oil.
Concentration of BaP in
brines
0.3-1.1 Product of the above
ppb three values. (BaP
is an aromatic
hydrocarbon.
-199-
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TABLE 7-1 (CONT.)
PARAMETER
VALUE
RATIONALE
Bioaccumulation factor:
Hg
BaP
104-105
236
Laboratory bioaccumu-
lation experiments with
Crassostrea; up to 80
day exposure (Kopler,
1974)
BaP accumulated in clam
Rangia cuneata in 24 hr
period. (Neff and An-
derson, 1975)
Maximum permissible level 0.5 ppm
of Hg in seafood
Skerfving (1972;
EPA Water Quality Criteria:
Ag
As
Cd
CN
Cr
Cu
Hg
Ni
Pb
Zn
Phenol
0.001 ppm
0.05 ppm
0.005 ppm
0.005 ppm
0.01 ppm
0.01 ppm
0.0001~ppm
0.1 ppm
0.01 ppm
0.07 ppm
(n.a.)
Taken from 1973 and
1975 EPA Water
Quality Criteria
Documents.
Concentrations below which
no effects were reported on
marine or estuarine organisms
in the literature:
Oilfield brine
Crude Oil
Ag
As
Cd
CN
Cr
Cu
Hg
1%
0.001 ppm
0.0005 ppm
3.0 ppm
0.08 ppm
(n.a.)
1. 0 ppm
0.002 ppm
0.002 ppm
Tables and text,
Chapter Six.
-200-
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TABLE 7-1 (CONT.)
PARAMETER
VALUE
RATIONALE
Ni
Pb
Zn
Phenol
0.06 ppm
0.1 ppm
0.006 ppm
0.6 ppm
Minimum reported 96 hr
LCSO's (actual or extra-
polated from 48 and 24
hr values), for adult
organisms:
Crude oil a
Crude oil WSF
Oilfield brine
Ay
As
Cd
CN
Cr
Cu
Hg
Ni
Pb
Zn
Phenol
5 ppm
6%
22%
0.04 ppm
8 ppm
0.2 ppm
(n.a.)
17 ppm
0.2 ppm
(n.a/)
17 ppm
200 ppm
1 ppm
1. 7 ppm
Tables and text,
Chapter Six. See
Section 7.2.3.
Extrapolated from data given by Anderson. The figure
represents the dilution of the complete soluble fraction,
not the concentration of hydrocarbons in the final dilution.
-201-
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REFERENCES FOR TABLE 7-1
Neff, J. and Anderson, J. "Accumulation, Release and Distri-
bution of Benzo[a]pyrene-C14 in the Clam Rangia cuneata,"
in American Petroleum Institute et al. 1975 Conference
on Prevention and Control of Oil Pollution - Proceedings.
American Petroleum Institute. Washington, B.C., 1975.
Anderson, J., et al. "Characteristics of Dispersions and
Water-Soluble Extracts of Crude and Refined Oils and
Their Toxicity to Estuarine Crustaceans and Fish."
Marine Biology 27 (1974): 75-88.
Kopfler, F.C. "The Accumulation of Organic and Inorganic
Mercury Compounds by the Eastern Oyster (Crassostrea
virginica)." Bulletin of Environmental Contamination
and Toxicology 11 (1974): 275-280.
Skerfving, S. "Mercury in Fish — Some Toxicological Con-
siderations." Food and Cosmetics Toxicology 10 (1972):
545-556.
-202-
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BaP in other food sources. For this purpose a final con-
centration in food of 1 ppb was defined as unacceptable. It
should be emphasized that this is not to be interpreted as a
safe level, only as an unacceptable level which should not
be exceeded. BaP is a potent carcinogen, and no information
is available to estimate a threshold level or even to
suggest that one exists.
7.2.3 Difficulties Involved in Use of Application
Factors
The question arises of whether an application factor of
0.01 applied indiscriminantly to the 96 hr LC50 of the most
sensitive organism studies is an appropriate criterion for
use in estimating safe levels. The problems which can
result when this approach is applied to the extremely low
LCSOs observed for juvenile and embryonic forms is illus-
trated by the case of silver., A 48 hr LC50 of 0.005 ppm has
been reported for silver for Crassostrea embryos. Using the
relationship between 96 hr and 48 hr LC50's discussed in
Section 7.2.2, this is shown to imply a 96 hr LC50 of
0.000835 ppm, or an application factor threshold of (0.01)
(0.000835) = 8.35 x 10° ppm. This is, however, far below
the concentration of silver in natural, unpolluted sea
water, which is 0.3 ppb or 3 x 10~4 ppm. Clearly, the
application factor approach is not realistic in this case,
since it leaves us with the conclusion that unpolluted sea
water is an unacceptable environment for marine organisms.
The application of the 0.01 factor has therefore been
restricted in this study to toxicity data for adult forms. It
is extremely important to emphasize, however, that the problem
of choosing an application factor to derive "safe" levels
of pollutants from acute toxicity data is by no means a simple
one, nor is there any evidence that it can be solved in a
thoroughly convincing way. Indeed, it is unreasonable to
expect a simple relation to exist between the relatively
high level of a pollutant capable of inducing mortality in
a short period of time, and the low levels which, under con-
ditions of chronic exposure, may affect one or more of the
multitude of different biological processes or behavior pat-
terns exhibited by various organisms at all stages of their
For information on levels of BaP in food sources, see
National Academy of Sciences, Committee on Biologic Effects
of Atmospheric Pollutants, Particulate Polyeyelie Organic
Matter, Chapter 14 (Washington, D.C., 1972), pp. 160-165.
-203-
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life cycles. Further discussion of the complexities of the
subject is given in a review paper by Bernhard and Zattera.4
7.2.4 Numerical Calculations for Hackberry Bay
The calculations performed for unsafe zone areas for
individual brine constituents and for combined effects in
Hackberry Bay are shown in Table 7-2. Because of the
significant compositional differences between crude oil and
the crude oil water-soluble fraction, it was decided to use
only the data on the water-soluble fraction for estimating
the toxicity of the hydrocarbon fraction of brines.
A further advantage of this is that the dispersion of
crude oil WSF around the discharge point can be modeled much
more accurately than can the dispersion of total oil hydro-
carbons. This is because the predominantly aromatic WSF
hydrocarbons are degraded much more slowly by hydrocarbono-
clastic (hydrocarbon degrading) microorganisms in the marine
environment than are non-WSF hydrocarbons. Therefore, their
concentration distributions can be predicted much more
accurately by the brine dispersion model used in this
report, which only takes physical dilution forces into
account.
The individual effects analysis (Table 7-2) suggests a
toxicity threshold of about 0.06 percent brine dilution.
The combined effects analysis obtained by summing the NDF's in
Table 7-2 (see Section 7.1) reduces this to about 0.04 per-
cent. Both estimates may tend to be conservative s'ince some
of the contaminants will probably be subject to effective
concentration reductions greater than those predicted by
the dispersion model as a result of adsorption, sedimenta-
tion, and (in the case of trace metals) physiological in-
activation by chelation. On the other hand, the individual
effects analysis, as mentioned above, does not take into
account the effects of emulsified oil hydrocarbons in the
brines. Moreover, the facts that the limited amount of
available data regarding the detailed composition of oil-
field brines exhibits a wide range in the concentrations of
brine constituents (see Table 3-2), and that the state of
knowledge of the potential impacts of trace metals and oil
4
M. Bernhard and A. Zattera, "Major Pollutants in the
Marine Environment," in E.A. Pearson, ed., Marine Pollution
and Marine Waste Disposal (New York: Pergamon Press, 1975).
-204-
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I
NJ
O
Ul
I
TABLE 7-2
CALCULATIONS FOR HACKEERRY BAY
ESTIMATED "SAFE"
CONTAMINANT CONCENTRATION
Ag
As
Cd
Cr
Cu
Hg
Hg (as a
food
contaminant)
Ni
Pb
Zn
Crude Oil
WSF
BaP (as a
food
contaminant)
Phenol
CN
Total NDF for
Combined Effects
Analysis01
(ppm)
0.0004
0.05
0.002
0.01
0.002
0.0001
c
0.06
0.01
0.01
0.06%
4 x 10~6
0.6
0.005
CONCENTRATION
BRINE
(ppm)
0.05
0.37
0.28
0.12
0.194
0.036
0.036
0.39
0.30
1.25
100%
0.001
3.5
0.007
IN PERCENT DILUTION
NDF3 AT NDF (= 100/NDF)
(ppm)
117
7
141
12
97
356
l,187b
6
30
125
l,600b
250
6
1.4
2,500
0.86
13.64
0.71
8.11
1.03
0.28
0.08
15.5
3.37
0.8
0.06
0.4
17.14
71.4
NDF = necessary dilution factor, i.e. dilution necessary to reduce each constituent
to its safe level.
bLargest NDF's.
°Safe level is essentially at or below natural level in seawater ( = 0.03 ppb = 3 x 10~5 ppm)
See Section 7.1. The NDF's for BaP and Hg as food contaminants are not included
in the total NDF.
-------
hydrocarbons is rapidly expanding, suggest prudence in estima-
ting the potential impacts of brine disposal in marine and
estuarine waters. Accordingly, a "best guess" of a 0.05 percent
(2,000:1) dilution was made as an estimate of a safe level of
brine dilution.
Since the "safe" level is below the 0.18 percent back-
ground brine levels predicted by tidal flushing calculations,
essentially the whole of Hackberry Bay is included in a zone
of impact.
7.2.5 Ecological Considerations
The Barataria Bay region, in which Hackberry Bay is
located, is a highly productive coastal wetlands area and
one of significant commercial importance. Therefore, any
brine related impacts produced in that area are likely to be
ecologically and economically significant (see Appendix A).
The salt waterbodies associated with the coastal salt
marshes of the Barataria Bay region (Hackberry Bay is one
such waterbody) support high levels of primary production by
diatoms, coccoid blue green algae, green algae, and nanno-
plankton. This primary production supports a large number
of herbivores, including Acartia tonsa (the dominant copepod
of the region), menhadden, and mullet. Detrivores are
numerous in the region including commercially important
species of penaeid shrimp, blue crabs, and oysters. Important
carnivores include ctinophores (which feed on zooplankton),
fishing birds, diving ducks, spotted sea trout, sea catfish,
silversides, anchovy, and the bottlenosed dolphin.
Many commercially important species, although they are
not full-time residents of the Barataria Bay area, spend at
least part of their life cycle there. The blue crab, which
supports a large fishery, spawns in lower estuarine and Gulf
waters, although the larval stages (zoae and megalops) are
spent in open Gulf waters. Near the end of the megalops
stage the blue crabs may enter tidal inlets, and the first
nine months of the juvenile stage are spent in the upper and
lower estuary. The second year as a juvenile is spent in
the upper estuary where the crab grows to full maturity and
mates. It is at this time that crabs are usually fished —
usually from ages 12 to 18 months. The panaeid shrimp
(including the white, pink, and brown shrimp), also com-
mercially important, follow a similar life cycle pattern.
-206-
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Fish species which spawn in the Gulf and use the
Barataria Bay as a nursery ground include the large-scale
menhadden, the Atlantic croaker, the spotted and sand sea
trout, the silver percy, the striped mullet, the spot, and
the bay whiff.
More detailed information on the ecology of this highly
productive region is given in Appendix A.
7.2.6 Delineation of Alternative Impact Zones
The approach adopted in this report was to summarize
impacts at each site by estimating the area of an impact
zone in which some significant level of toxic impacts on
marine hydrocarbons would be felt. It would be desirable,
as discussed in Chapter Six, to be able to determine the
nature and magnitude of impacts which would occur in each of
a set of concentric regions inside of this impact zone.
Unfortunately, such an analysis is made almost impossible by
the complex sets of interactions which would almost certainly
be observed between the toxic impacts of the dozen or so
contaminants found in brines. Particular sublethal effects
may be observed as the' result of individual exposure to
several different pollutants, and there is no method avail-
able for estimating the way these pollutants will interact
in a mixture to produce these particular effects.
Some qualitative feeling for how the type and severity
of effects vary with concentration can be gained from
Table 7-3, in which the effects found for successive levels of
dilution of silver from its initial maximum reported con-
centration in the brine are listed. Note that the effects
become less severe towards the edge of the unsafe zone, and
that at its borders only embryonic forms are affected.
Unfortunately, it would be impossible to predict how the
types of effects produced by silver in an inner dilution
zone would interact with the effects produced by other
pollutants in the same physical zone.
7.3 Analysis of Impacts at Other Sites; General Comments
As was discussed in Chapter Two, this analysis incor-
porates a number of site specific features, including the
resident species, the dispersion characteristics of the
site, and the contaminant concentrations and discharge
rate of the brine. An examination of the quantitative data
suggests that the most important of these features in determining
the magnitude of impact at a site are the discharge rate
-207-
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TABLE 7-3
TYPES OF EFFECTS REPORTED IN THE LITERATURE FOR SILVER AT
VARIOUS RANGES OF CONCENTRATIONS FOUND INSIDE THE "UNSAFE" ZONE
DILUTION
RANGE
CONCENTRATION
RANGE
EFFECTS NOTED
i
NJ
O
CO
I
1-10
10-100
100-1000
0.10-0.01
0.01 ppm-1.0 ppb
1.0 ppb-0.10 ppb
Abnormal movement in mud snail
Nassarius induced by 72 hr exposure.
96 hr LC50 for Fundulus; 96 hr
exposure caused severe reduction of
levels of 3 liver enzymes in Fundulus.
Mortality of Crassostrea embryos;
toxicity threshold for adult stickle-
backs.
Induction of developmental abnormalities
in embryos of various sea urchin species,
DILUTION
TYPES OF EFFECTS
1-10
10-100
100-1000
Lethality of adult organisms, significant
sublethal effects.
Mortality of embryonic forms.
Teratogenesis, induction of developmental
abnormalities.
-------
and dispersion characteristics, the latter being determined
by depth, tidal currents and drift or freshwater current
velocity. Since information on toxic effects was not avail-
able for all important species at each site, it seemed
reasonable to base all the impacts assessments on the total
group of marine species for which data were available.
Furthermore, because of the wide variability of composition
of produced water at different sites within a geographical
region (a variability which was in most cases larger than
the differences observed between different regions), the
assumption was made that the brine compositions for all
sites could be adequately represented by the concentrations
which were used for Louisiana brines, the derivation of
which was explained earlier. Therefore, the chief focus in
comparison of the sites was comparison of the dispersion
model outputs. For all sites, an impacts threshold of
approximately 0.05 percent brine dilution was assumed.
7.4 Analysis of Impacts at Cook Inlet
7.4.1 Area/Concentration Relationships
Area/concentration curves for Cook Inlet are shown in
Figure 7-4. The curves were computed down to 0.05 percent
dilution, the toxicity threshold being assumed in this
analysis. Because of the enormous tidal flushing volumes,
the calculated background concentration is far below this
level and can be ignored. Notice that the base case curve
is also a best case over part of its range.
The estimated area of the impact zone for this site is
between 700,000 ft2 (0.025 mi2) and 50,000,000 ft2 (1.79 mi2)
The base case estimate is 5,000,000 ft2 (0.18 mi2) .
7.4.2 Ecological Considerations
Cook Inlet can be divided into three ecologically semi-
distinct parts (see Figure 7-5). The upper Inlet lies east
of a line extending northward from Point Possession; the
middle Inlet, where most of the current brine discharge
occurs, includes waters from the upper Inlet southwestward
to the latitude of Tuxedni Bay (60° 25' N); and the remaining
portion of Cook Inlet, south of Tuxedni Bay and Clam Gulch,
is commonly called the lower Inlet. This last region has
the clearest waters, and is the most productive, supporting
all major species of fish, shellfish, and marine mammals
found in Cook Inlet. It is this lower Inlet region which is
of most interest to biologists and agencies concerned with
-209-
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100,000-,
10,000 •
1,000.0:
<
<
100.0:
10.0
1.0
0.1
COOK INLET
WORST CASE
BEST
CASE
.01
11 | 1 1—i i i i i—i—
.10 1.0
CONCENTRATION (%)
i i i 111
10.0
Figure 7-4. Area/concentration curves for Cook Inlet.
-210-
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I
CO
Figure 7-5. Map of Cook Inlet.
-------
wildlife and fisheries management. Therefore, relatively
little work has been done in the mid Inlet, which is the
area of interest to this analysis, since it contains the
major oil production areas of the Inlet. What data are
available suggest that the mid Inlet is relatively non-
productive .
It appears that very few species exist in the silt
laden waters of the western and upper half of the Inlet
(including the mid-Inlet region). The high tidal amplitude
and the strong tidal currents which scour the bottom make
survival difficult for most benthic organisms. The great
loads of suspended sediment in these regions limit penetration
of light, confining photosynthesis to a very shallow photic
zone. Productivity increases as one moves oceanward, to
cleaner, more saline waters. The lower Inlet waters provide
habitat for a variety of sport and commercially important
fish and shellfish, and numerous other non-fished species.
In short, the impacts produced by oil platforms in the
mid-Cook Inlet provide us with a case which contrasts strongly
with that of Hackberry Bay. Not only are the zones of
impact smaller in Cook Inlet (as a result of site specific
dispersion patterns), but the area impacted seems much less
important, both ecologically and economically.
7.5 Analysis of Impacts at Grand Isle
7.5.1 Area/Concentration Relationships
Area/concentration curves for the near offshore site at
Grand Isle are shown in Figure 7-6. Since this site is in
the open ocean, outside the Gulf of Mexico barrier islands,
the tidal flushing calculations were inappropriate, and no
minimum background level was assumed. Two different base
cases were used, one assuming a discharge site located
fairly close to the shore of Grand Isle, and one assuming a
site further away from shore. (These two base cases are
cases N1A and N2A, using the nomenclature of Chapter Five.
The discharge-to-shore distances and other input parameters
assumed for these cases are discussed in detail in that
chapter.)
The estimated area of the impact zone for this site is ~
between about 900,000 ft2 (0.032 mi2) and about 9,000,000 ft
(0.32 mi2).
-212-
-------
1000.0
100. Ch
<
<
10.0-
1.0
0.01
N2B VN
N1D
GRAND ISLE
WORST CASE
BEST CASE
N2B
N1A (BASE CASE 1)
N2A (BASE CASE 2)
N1E
NIB
NIC
0.1 1.0
CONCENTRATION (%)
10.0
Figure 7-6. Area/concentration curve for Grand Isle
site in near offshore Gulf of Mexico.
-213-
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7.5.2 Ecological Considerations
The near offshore Gulf of Mexico is a highly productive
region (see Appendix A), which yields extremely high catches
of commercially important fish and shellfish. The variety
and productivity of this region is suggested by Table 7-4,
which lists some of the significant consumer species found
there.
7.6 Analysis of Impacts at the Far Offshore Gulf of Mexico
Site
7.6.1 Area/Concentration Relationships
Area/concentration curves for the far offshore site in
the Gulf of Mexico are shown in Figure 7-7. Since this site
is in the open ocean, tidal flushing calculations are in-
appropriate, and no minimum background level is assumed.
The estimated area of2the impact zone for this site is ~
between about 3,000,000 ft (0.1 mi2) and about 10,000,000 ft
(0. 33 iru.2) .
7.6.2 Ecological Considerations
The far offshore Gulf of Mexico is a highly productive
region, which yields extremely high catches of commercially
important fish and shellfish, as does the near offshore
Gulf. The species shown in Table 7-4 can also be found in
the far offshore waters of the Gulf.
7.7 Summary of Impacts Analysis
The magnitude of impacts observed at each of the study
sites is summarized in Table 7-5.
7.8 Comments on Agreement of Results with Field Studies
The extension and, more importantly, the validation of
this model will require the implementation of field studies
specifically concerned with the analysis of brines, water
column samples, and ecological communities in the vicinity
of production platforms. Previous studies in general have
not generated sufficient data on the relationship between
concentrations of metals and hydrocarbons in the water
column and in the discharged brine to confirm the predictions
-214-
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TABLE 7-4
KEY CONSUMERS - NEAR AND FAR OFFSHORE GULF WATERS
(ADJACENT TO BARATARIA BAY, LOUISIANA)
INVERTEBRATE
FISH
COMMERCIAL
SPECIES
(Brown Shrimp)
if Penaeus setiferus
(White Shrimp)
if penaaus durorarun
if ft Anchoa adtchilli
(Bay Ar.chovy)
(Sand Sea Trout)
ft Pearilus burti
(PirUc Shriai?)
__ _
(Gulf Butterfish)
ir •& gallinectes sagicis
(Blue Crab)
^
(Fringed Flounder)
SPORT SPECIES
•fr Cantropistes gniladelghica
(Rack 5«a Bass;
•fr Trichj-ums lapturus
(Cutlass Fish)
-^ Leiostonms x_an_thurus
(Spot)
_ _
(s«a Catfish)
if -fr yj.grogQggn undulatos
(Atlantic CroaJcar)
£ CH 1 Q r g_jtcomb rus chrysu
(Atlantic Bunker)
TROPHICALLY
IMPORTANT
SPECIES
• jjagmarus gg.
(Ampnipod)
• if Acartia ton.sa
(Copepod)
• if Paracalanus st^
(Copepod)
if >qphopenaeu8 so^
(Sea Bob)
if j^quilla sg.
(Mantis ShriOTi)
Prionotug rcscua
(Blue Spotted Sea Robin)
ft Stama sg_.
iTcm)
ft Ayt^a affiniS
(L«saer Scaup)
ft Larus atrieillia
(Laughing Gull)
ft Fregata maoni.ficans
CFrigata Bird)
ft Larus ph^iladftlphia.
(Bonaparte' a gull)
ft Tursippa truncatua^
(Bottlenose Dolphin)
. IS.
(P«X«cypod)
ir*tr Cibanarius vittatus
THermit~Crab)
Lolitjuncula brevis
ENDANGERED
SPECIES
ft Pelecanus qceieJttalia
(Brown Pelican)
~* D«tritivere
•ft- Carniwora
• Harbivorv
-215-
-------
WOO.
rg
B.O-
001
FAR OFFSHORE
GULF OF MEXICO
F2,F4
T 1 1 1—I I I |
to
i—I—r i r™ i
100
CONCENTRATION (%)
Figure 7-7. Area/concentration curves for far offshore
Gulf of Mexico site.
-216-
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TABLE 7-5
SUMMARY OF IMPACTS
SITE
LOCATION
PROBABLE AREA OF
IMPACT ZONE
ECOLOGY
Hackberry
Bay
Onshore
Cook Inlet
Onshore
Grand Isle
Gulf of
Mexico Site
Near
Offshore
Far
Offshore
entire bay (ca.
192,000,000 ft2
or 6.9 mi2)
ca. 5,000,000 ft'
(0.18 mi2)
700,000 -
9,000,000 ft'
.2,
highly productive,
supports blue
crab, panaeid
shrimp, and other
commercially
important spp.
relatively in-
fertile due to
continuous bottom
scouring by tidal
currents and to
high turbidity
highly productive;
supports several
(0.025 - 0.32 mi ) commercially
important or
sport species
3,000,.000 -
10,000,000
(0.11 - 0.36 mi
.2.
highly productive;
supports several
commercial or
sport species
of this dispersion model used in this report, nor have
they provided detailed information on brine discharge rates
at study sites. Furthermore, studies of the condition of
ecological communities near production platforms frequently
suffer from an important methodological deficiency in that
they often analyze the condition of the ecosystem by comparison
with reference points distant from the production platform,
and therefore presumably unimpacted. The existence of
chronic, long-term pollution problems in some areas, however,
may mean that these reference points are themselves strongly
impacted. For this reason, the actual magnitude of impacts
is probably best determined through comparison with a temporal,
rather than a spatial, reference point. The Bureau of Land
-217-
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Management is currently in the process of organizing such a
"pre-impact" baseline study at the site of future offshore
drilling operations at Georges Bank, Maine, and at other
sites off California, Virginia, and South Carolina.
Furthermore, field studies on the health of ecosystems
do not provide any data on what may well be the most important
impact of offshore oil operations, which is the bioaccumula-
tion of toxic brine constituents by organisms which are
eventually destined for human consumption. Potential toxic
impacts of the bioaccumulation of mercury and benz[a]pyrene
by marine organisms have already been discussed, and similar
problems may be expected as a result of the bioaccumulation
of other metal or hydrocarbon brine contaminants. The data
in Table 7-2 suggest that this class of impact would be
serious down to about three orders of magnitude of brine
dilution. This is an especially serious problem in areas
such as Hackberry Bay, which are important fishery regions.
For these reasons it is difficult to confirm the predic-
tions of the model on the basis of field data. Nevertheless,
the following general comments can be made:
1. The literature of brine impacts shows that the
magnitude of the impact is highly site specific,
and seems to be correlated most strongly with the
dilution characteristic of the receiving waterbody.
Thus, Mackin found little ecological damage in the
relatively open waterbodies he studied in the Gulf
of Mexico, while the Chiltipin Creek studies
demonstrated an extremely strong and significant
impact in an area with insufficient current and
tidal flow to rapidly dilute discharged brines
(see discussion in Chapter Five). Furthermore,
Chiltipin Creek impacts were found to be consid-
erably ameliorated during periods of high rainfall,
which suggests the importance of dilution effects.
2. The tendency for resiliency in established eco-
systems and the possibility of selection for
pollution-resistant subpopulations over the course
of several generations may considerably ameliorate
the effects predicted in this analysis. Further-
more, the oxidation of oil hydrocarbons by marine
microorganisms may lessen the magnitude of oil-
related impacts (although metals would probably be
scavenged much more slowly than hydrocarbons from
the water column). Extensive examination of this
possibility through the implementation of field
studies in the Hackberry Bay and Cook Inlet areas
is indicated.
-218-
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3. Mackin and Hopkins reported that oyster mortality
along the Louisiana coast (including the Barataria
Bar area) was not correlated with proximity to oil
fields. Levels of trace metals in oysters and the
existence of a number of sublethal effects were
not examined in this study. The report also
demonstrated that there is a significant natural
variation in oyster mortality, due to current,
tide, and salinity variations which is much greater
than the estimated magnitude of brine-related
mortality, and which was observed before offshore
operations began in the Louisiana area. According
to Mackin and Hopkins: "Field studies of Texas
A&M Research Foundation biologists, beginning in
1947, confirmed reports that mortality rates were
high on many Louisiana oyster beds and that there
was a seasonal cycle in mortality correlated with
temperature. ... The regular and predictable
nature of this mortality indicated that it was not
abnormal."
4. Mackin (see Chapter Five) and, more recently,
Neff, observed a zone of ecological stimulation
lying outside of the zone of impact which they
observed in their field studies. They attribute
this to the biodegradation of petroleum hydro-
carbons by communities of marine microorganisms,
which enable the hydrocarbons to be used as a
nutrient source by the marine communities. This
may be a significant feature of the impact of
petroleum on marine ecosystems, and deserves
further attention. It is suggested that further
field and laboratory studies be carried out in
this area.
In short, the currently available field data are
inadequate for quantitative validation of the model, although
some of the qualitative data are consistent with the analysis
(existence of concentric zones of impact, importance of
site specific dilution rates, etc.). Ecological field
studies are hampered at many sites by the existence of wide
natural variations in mortality parameters (both seasonal
and random) which swamp variation due to brine-related
impacts.
J.G. Mackin and S.H. Hopkins, "Studies on Oysters in
Relation to the Oil Industry," Publications of the Institute
of Marine Science (7) (1961): 1-131.
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CHAPTER EIGHT
CONCLUSIONS
The data and analyses discussed in this report support
the following conclusions:
• Presence of Toxic Substances in Oilfield Brines
Produced brines contain a variety of substances known
to have lethal and sublethal toxic effects on marine and
estuarine organisms. These toxic constituents include oil
hydrocarbons, trace metals (including arsenic, cadmium,
chromium, copper, lead, mercury, nickel, silver, and zinc),
phenol, and cyanide. Some of these toxicants have been
measured in produced waters at concentrations up to several
orders of magnitude higher than the corresponding EPA water
quality criteria. In addition to their effect on marine
organisms, many of the brine components (particularly mercury
and the polynuclear aromatic hydrocarbon benz[a]pyrene)
are known to be bioaccumulated in shellfish which may be
used for human consumption and so present a potential human
health threat.
• Treatment Methods
Current methods used for separating oil hydrocarbons from
produced water have little if any effect on levels of
dissolved contaminants. These include the dissolved aromatic
hydrocarbons which are among the most toxic hydrocarbon
components of brines, and the trace metals.
• "Safe" Levels
The impact exerted by contaminants present in the
discharged produced water depends on the concentration
levels of the contaminants to which biota in the receiving
waters are exposed. The concentrations will be a maximum in
the immediate vicinity of the point of discharge, and will
in general decrease with increasing distance from the dis-
charge point. Toxicological data on the effects of brine
toxicants on marine and estuarine organisms, in conjunction
with data on produced water contaminant concentrations, suggest
(as discussed in Chapter Seven) that a 0.05 percent level
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of dilution of oilfield brines (i.e., 1 part brine to 2,000
parts receiving water) is "safe"; i.e., it will produce no
significant level of lethal or sublethal effects on resident
organisms and will prevent the bioaccumulation of brine
constituents to dangerous levels in human food organisms.
Accordingly, a convenient measure of the impact associated
with a given brine discharge is the area around the discharge
point that can be expected to be subjected to produced
waters at concentrations greater than or equal to 0.05 percent.
It should be noted, however, that the 1:2,000 safe level is
based on the maximum produced water contaminant concentrations
which have been measured. Since data on contaminant levels
in produced waters are sketchy, and since contaminant concen-
trations are highly variable, both between different geographic
regions and different sites in the same region, "safe"
levels at all sites will not necessarily occur at the 1:2,000
dilution level used in this analysis. It is also extremely
important to bear in mind the fact that the state of knowledge
regarding toxic effects of trace metals and oil hydrocarbons
is expanding rapidly at present. Hence, the estimate of a
safe level used here should be regarded as provisional only,
subject to revision on the basis of increased knowledge of
toxic effects.
• Evaluation of Impacts
The area of the 0.05 percent dilution zone depends on a
number of highly site specific factors. Such factors include
the rate at which produced water is discharged, the depth of
the receiving water, currents (tidal, freshwater, drift),
and diffusion coefficients. Other site specific processes
also affect contaminant dispersion but cannot be readily
quantified. Processes in this category include adsorption
of contaminants on suspended particles, sedimentation and
transport of sediments, chemical transformation, and biode-
gradation. Severity of impact depends not only on the
numerical size of the affected area but also on its ecology.
Ecological characteristics are important in that they determine
the value of the area being impacted in terms of the primary
production the area supports, the commercially important
species which live there, and the importance of the region
to particular lifecycle stages of other economically or
ecologically important organisms. Finally, impacts may also
be evaluated in terms of the size of the impacted area
relative to the size of the receiving waterbody. The same
area may represent a much severer impact in a relatively
small bay than in a larger, less enclosed waterbody.
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• Modeling of Brine Dispersion
The site specific factors of discharge rate, depth of
receiving water, currents, and diffusion coefficients have
been incorporated into a computerized dispersion model which
can be used for estimating the areas of the unsafe (concen-
tration greater than or equal to 0.05 percent) zones at each
site. For each of four specific sites (Hackberry Bay,
Louisiana; Grand Isle, Louisiana; Cook Inlet, Alaska; and
the Ship Shoal oil field in the far offshore Gulf of Mexico),
the computer model was used to give estimates of areas
expected to be subjected to concentration levels down to
0.05 percent. Several sensitivity analyses were performed
for each site in order to allow for uncertainties in avail-
able data on input parameter values and simplifying assumptions
incorporated in the model. The results of the computations
for the four sites are summarized in Table 8-1.
TABLE 8-1
SUMMARY OF IMPACTS
SITE
LOCATION
PROBABLE AREA OF
IMPACT ZONE
ECOLOGY
Hackberry
Bay
Onshore
Cook Inlet
Onshore
Grand Isle
Gulf of
Mexico Site
Near
Offshore
Far
Offshore
entire bay (ca.
192,000,000 ft2
or 6.9 mi2)
ca. 5,000,000 ft'
(0.18 mi2)
700,000 -
9,000,000 ft'
.2,
highly productive,
supports blue
crab, panaeid
shrimp, and other
commercially
important spp.
relatively in-
fertile due to
continuous bottom
scouring by tidal
currents and to
high turbidity
highly productive;
supports several
(0.025 - 0.32 mi ) commercially
important or
sport species
3,000,000 - .
10,000,000 ft'
(0.11 - 0.36 mi")
. 2,
highly productive;
supports several
commercial or
sport species
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• Onshore Benefits
No similarity was observed between estimated impacts at
the two onshore study sites. In Hackberry Bay the impacts
are estimated to be rather severe (see Table 8-1). Hackberry
Bay is also a productive fishery area. In the mid Cook
Inlet area tidal mixing results in a rapid dilution of the
discharge away from the discharge point. The impacted area
is proportionally small compared with the area of the mid
Cook Inlet, and, in addition, is naturally unproductive due
to tidal bottom scouring and high natural turbidity levels.
Therefore, impacts are judged to be relatively small in the
mid Cook Inlet.
The benefits which would be achieved if the proposed
near offshore BATEA regulations are extended to apply to
onshore discharges are thus highly site specific. Small,
enclosed, shallow, and biologically productive bays with
large brine discharges will probably stand to benefit con-
siderably. The benefits to be achieved by prohibiting small
discharges of produced water into larger and deeper coastal
embayments with adequate tidal and freshwater mixing are
likely to be correspondingly small. A first order estimate
of the magnitude of the benefits to be achieved by a "no
discharge" regulation can be obtained through the use of the
tidal flushing calculations described in Chapter Four,
together with some considerations of the ecology and economic
importance of the region being impacted.
• Near Offshore Benefits
In the near offshore Gulf of Mexico waters, the analy-
sis performed for a single site is insufficient to serve as
a complete basis for estimating regional impacts. In order
to extrapolate from impacts at a single platform to regional
impacts, data on platform locations and discharge rates
throughout the region are needed.
The benefits to be achieved by prohibiting the dis-
charge of produced waters into near offshore waters will
therefore depend critically on the density of production
platforms and rates of discharge in a particular region. In
areas where platforms are highly concentrated, aggregate
discharge levels are likely to be large, and impact zones
may overlap. In such areas significant benefits could
probably be achieved. In areas with low platform densities
and only small rates of brine discharge the benefits are
likely to be less pronounced. The analysis performed in
this study should, therefore, be supplemented by the assembly
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of a data base providing information on the location and
discharge rates of production -platforms in near offshore
Gulf of Mexico waters (projected development might also be
incorporated in this supplementary study). Since the rate
at which water is produced in a given field tends to in-
crease with the age of the field, assessment of the bene-
fits to be achieved by prohibiting the discharge of pro-
duced water should take into account not only the present
rate at which water is produced in a field, but also the
increased rate at which water can be expected to be pro-
duced in the future.
• Far Offshore Benefits
In far offshore Gulf of Mexico waters, the major con-
clusion to be drawn from this study is that there would
probably be little reduction in impacts resulting from the
imposition of BATEA regulations over and above those already
achieved by the BPCTCA restrictions. The more stringent
treatment requirements imposed on far offshore platforms by
the BATEA requirements will do little to remove the dissolved
hydrocarbons and trace metals which are responsible for much
of the toxic impact of oilfield brines. The impacts resulting
from the produced water discharge of a given field can be
expected to increase with the age of the field, since the
rate of water production generally increases with the age
of the field.
• Field Data
It is recommended that programs of field data collec-
tion be initiated to provide further information on the
composition and composition variability of produced waters,
and on dispersion characteristics and ecological features of
brine discharge sites.
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APPENDIX A
ECOLOGICAL CHARACTERIZATION OF PRODUCTION SITES
A. 1 Introduction
The ecological characterization of Cook Inlet, Alaska
and Barataria Bay, Louisiana, presented in the following
sections, provides an introduction to the key physical,
chemical, and geological features of these areas. These
sections attempt to present the study areas as ecological
systems, involving dynamic interactions between biota and
environmental variables, and to describe the dynamics of
the principal factors which determine the fates of contami-
nants contained in discharged produced water.
Physical parameters play an important role in deter-
mining pathways of discharged brine in the environment and
in determining the nature and severity of effects which the
hydrocarbons, trace metals and high salinities have on marine
organisms. Currents, winds, tides and depth of water are
known to be the key factors influencing effluent dispersion
in the water column, while turbidity, suspended sediments,
and sedimentation rates will influence the residence time of
effluent components in the water column and in the bottom
sediments, through absorption, sedimentation and floccula-
tion. Bottom sediments of varying mineral composition, and
grain size have different capacities to adsorb, desorb, and
retain effluent components. In assessment of impacts, fac-
tors such as temperature, salinity, and dissolved oxygen
levels, which often increase or decrease the toxicity of
trace elements to aquatic organisms by changing metabolic
rates or enzyme activity, are of great importance. These
parameters also influence rates of microbial degradation of
oil.
In some instances physical data can be used to draw
quantitative assumptions about effluent fates, as in the
case of dispersion models. Often, however, the state of
scientific knowledge is such that the interactions between
physical parameters and effluent components (e.g., tempera-
ture and trace metals), and the effects of these interactions
on living systems, are only understood qualitatively, and
must be discussed as potential events. It is felt that des-
cription of these parameters (and discussion of their inter-
actions in a later section) will provide some insight into
the variable nature of effluent impacts on these systems.
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Information on the biota of Cook Inlet and Barataria
Bay has been collected to facilitate identification of poten-
tial impacts from brine discharge. For the species of com-
mercial, sport and trophic importance, a description is given
of their preferred habitat at various stages in the life cycle,
and their place in the food chain.
The susceptibility of an organism to the toxic effects
of contaminants may vary with an organism's life cycle stages.
Habitat preferences may also vary throughout a life cycle.
For this reason, both factors must be considered together.
This will help to identify the pathways by which oil in the
water column or sediments can make contact with the biota.
Knowledge of feeding mechanisms such as deposit feeding,
filter feeding or membrane diffusion, will assist identifi-
cation of pathways in a similar manner.
Contaminant-induced effects, which change population
numbers of species in one trophic level, will in turn affect
predator and prey populations on other trophic levels. Pre-
dicting impacts of this nature requires knowledge of impor-
tant trophic interactions (food webs).
The characterizations of the study sites have been
organized by ecological units rather than by the "near
offshore," and "far offshore" distinctions made in the EPA
Development Document. For Louisiana, the ecological charac-
terization has been divided into two sections, one consisting
of the marshes and the waterbodies of Barataria Bay (which
are actually near offshore waters). The other section des-
cribes the near offshore and far offshore waters in the Gulf
of Mexico. The Cook Inlet characterization presents combined
information for near offshore and far offshore water of
Cook Inlet, because little data are available with which to
make a distinction. The Cook Inlet intertidal region is
treated as a separate ecological unit.
A.2 Cook Inlet Characterization
A.2.1 Introduction
Cook Inlet is a large tidal estuary in south central
Alaska, which flows into the Gulf of Alaska just east of the
base of the Alaskan Peninsula. It is 150 nautical miles
wide at its widest point and Knik and Turnagain Arms at the
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head of the Inlet are 45 and 43 nautical miles long, respec-
tively. 1
Figure A-l depicts the major bays, points, capes and
islands of Cook Inlet. For ease of discussion, we have
divided Cook Inlet into three semi-distinct ecological parts.
The Upper Inlet lies east of a line extending northward from
Point Possession. The waters of the Upper Inlet receive great
loads of suspended glacial sediment from the Susitna River,
Little Susitna River and the rivers emptying into Knik and
Turnagain Arms, and are extremely turbid.
The Middle Inlet, where brine discharge occurs, includes
waters from the Upper Inlet southwestward to the latitude of
of Tuxedni Bay (60°25" N). There are four onshore separation
platforms and three offshore facilities discharging brine into
the Inlet: the Union Oil facility located just south of
Kenai discharges the wastewater into a ravine along which it
flows to Cook Inlet waters. The Shell Oil facility near
Nikiska and the Marathon plant near West Foreland in Trading
Bay both discharge wastes into the Inlet by pipe.
Atlantic Richfield Company has a separation facility at
Granite Point which discharges wastes into a trough which
leads into Cook Inlet. Three offshore platforms owned by
Amoco have separation facilities and dump wastes directly
into Inlet waters. Figure A-l depicts the location of onshore
and offshore separation facilities.
The remaining portion of Cook Inlet, south of Texedni
Bay and Clam Gulch, is commonly called the Lower Inlet. This
region has the clearest waters, and is the most productive,
supporting all major species of fish, shellfish, and marine
mammals found in Cook Inlet.
Cook Inlet is bordered by a combination of tidal marsh,
mudflats, mountains and lowlands. Over 100 square miles of
tidal marsh are found in the Susitna Flats, upper Knik Arm,
Chickaloon Flats (in Turnagain Arms), in Trading Bay and in
Redoubt Bay. The Aleutian Range and Alaska Mountains lie to
the Northeast and the Chugach and Kenai Mountains lie to the
southeast. A rim of lowlands separates the mountains from
most of the Inlet though this rim is narrow or absent in the
Lower Inlet, where the mountains meet the sea. In the Upper
C.D. Evans, E. Buck, R. Buffler, et al., The Cook Inlet
Environment, A Background Study of Available Knowledge
(Anchorage: University of Alaska, Resources and Science
Center, Alaska Sea Grant Program, August 1972).
-229-
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I
to
U)
o
I
Figure A-l. Cook Inlet.
-------
and Mid Inlet these lowlands are wide, often forming mudflats,
and support fairly high densities of waterfowl.
Oceanographic and biological information is not readily
available on Cook Inlet waters. Interest in this type of
data has only developed recently, within the past 10 years,
and the logistics of data collection have presented problems.
The Lower Inlet is the area of most interest to biologists
and agencies concerned with wildlife and fisheries management.
Most Cook Inlet investigations seem to have produced data for
this region in particular. The Upper Inlet also has been of
interest to planners and managers due to the density of human
population found along Knik and Turnagain Arms. A number of
studies relating to waste disposal and civil engineering have
generated information about the Upper Inlet. The major items
of interest in the Mid Inlet are the offshore oil platforms
and the onshore separation facilities, refineries and chemical
plants. Aside from one major study performed by the University
of Alaska for the Collier Carbon and Chemical Corporation,2
there are very little data available about the Mid Inlet open
ocean or coastal environments. The characterization presented
here has pieced together published and unpublished information
into a coherent description of the ecology of Cook Inlet.
A.2.2 Temperature
Water temperatures in Cook Inlet range from near freezing
(-1.2° C) in February to a high of 15.2° C in August. The
Inlet is generally well mixed vertically and temperatures are
fairly uniform from top to bottom. Some thermal stratifica-
tion is observed on the western side of the Mid and Upper
Inlet in the region of freshwater outflow.-^ Figure A-2
depicts surface temperature distribution in May.
A.2.3 Depth
The Upper Inlet is a shallow, silt laden basin with
depths less than 20 fathoms. Turnagain and Knik Arms are
2
F.W. Hood, K.W. Natajan, D.H. Rosenberg, and D.D. Wallen,
Summary Report on Collier Carbon and Chemical Corporation
Studies in Cook Inlet, Alaska (College, Alaska: Institute
of Marine Science, University of Alaska, December 1968) .
Hood, Natajan, Rosenberg, and Wallen, Summary Report
on Collier Carbon and Chemical Corporation.
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60° -
Surface Temperature
Distribution
COOK INLET
Figure A-2. Surface temperature distribution - Cook Inlet.
(P.J. Kinney, J. Groves, and O.K. Button, Cook Inlet Environ-
mental Data, R/V Cruise 065 - May 21-28, 1968 (College, Alaska:
Institute of Marine Science, University of Alaska, Report No.
R-70-2, 1970), p. 14.)
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the shallowest areas with much of the bottom exposed as tidal
flat during low tide. There are two channels which extend
southward in the Mid Inlet and past Trading Bay, Redoubt Bay
and Upper Kenai, joining in an area west of Cape Ninilchik.
In the Lower Inlet south of Cape Ninilchik, the channel
deepens to 80 fathoms and widens to extend across the mouth
of the Inlet. Below the Forelands, the bottom slopes down-
ward, reaching depths over 100 fathoms south of the Inlet
entrance.^
The Mid Inlet bottom has a fairly gentle slope on the
eastern side, the waters reach a depth of 10 fathoms 2 miles
(near East Foreland) to 12 miles (in Upper Mid Inlet) off-
shore. On the western side of the Mid Inlet 10 fathom depths
occur from several hundred yards to 5 miles offshore. Figure
A-3 depicts changes in depth along a transect running from
the Marathon facility at West Foreland across the Inlet to
the Shell Oil plant in Nikiska. Shallow regions, less than
10 fathoms, are found surrounding Middle Ground Shoal, an
island adjacent to Trading Bay, and Kalgin Island off of
Redoubt Bay.
Cook Inlet has several deep holes, most of which result
from scouring of the sea floor. Between East and West Fore-
land in the Mid Inlet the bottom reaches a depth of 75 fathoms
and an 85-fathom hole occurs at the entrance to Kachemak Bay
in the Lower Inlet. In contrast, Kamishak Bay, on the western
side of the Lower Inlet, is relatively shallow, sloping
toward the Inlet center at a grade of 5 to 10 feet per mile.
A.2.4 Ice
Ice begins forming in the Upper Inlet in October and
extends into Lower Cook Inlet as determined by wind and
temperature. Intertidal areas become coated with ice during
repeated exposures. Along the tidal flats, ice and sand
accumulate and are stranded with each successive tide,
forming large clumps called stamuki which may reach a
4
D.M. Anderson, L.W. Gatto, H.L. McKim, and A. Petrone,
"Sediment Distribution and Coastal Processes in Cook Inlet,
Alaska," in Symposium on Significant Results Obtained from
the Earth Resources Technology Satellite-1, Vol. 1, Section B,
S.C. Freden, E.P. Mercanti, and M.A. Becker (eds.), (Washing-
ton, D.C.: National Aeronautics and Space Administration,
1973); and Evans, Buck, Buffler, et al., Cook Inlet Environ-
ment, Study of Available Knowledge.
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I
NJ
U)
W
O
A
-P
rt)
En
K
W
Q
5 -
10 -,
15
20
25
30
35
40
45
50 -
0 1
Y
West Foreland
(Marathon oil
facility)
4 5 6 7 8 9 10
DISTANCE FROM SHORE (Miles)
11
12 13
14
15
y
Nikiska
(Shell oil
facility)
Figure A-3. Bathymetry profile along a Mid Inlet transect, West Foreland to
Nikiska.
-------
thickness of 40 feet. Much of the ice found in the Inlet is
floe ice, which increases in thickness up to 1 inch per day.
Ice puts additional stresses on marine organisms in the
winter, particularly those in the intertidal region which
must freeze and thaw with each tidal cycle.
A.2.5 Tides and Currents
The tides of Cook Inlet are semi-diurnal with a notable
inequality between successive low waters. Mean diurnal
range of the tides varies from 13.7 feet at the entrance
to the Inlet to 29.6 feet at Anchorage. There is a 4.5
hour time lag between high water at the mouth of the Inlet
and high water at Anchorage. The mean diurnal tidal range
on the east side of the Inlet is greater (19.1 feet in East
Lower Inlet) than it is on the west side (16.6 feet in West
Lower Inlet). Tidal bores sometimes occur in Turnagain Arm,
reaching heights of 10 feet.6 Table A-l gives the mean
range (the difference in height between mean high water and
mean low water), the diurnal range (the difference in height
between mean higher high water and mean lower low water),
and the mean tide level (a plane midway between mean low
water and mean high water measured from the mean lower low
water level) for locations in Cook Inlet.
Three features strongly influence the tides in Cook
Inlet: topography, friction, and the Coriolis force. The
topography of the Inlet may increase tidal amplitude at
certain locations. In the absence of friction, tidal height
would remain constant between the mouth of the Inlet and
the Forelands, and then would steadily increase. The ampli-
tude at Anchorage would be twice that at the entrance.
However, as a result of friction, energy is lost. There is
a net inward transport of energy through the entrance to
replace this loss. Therefore, the form of the wave is pro-
gressive, with maximum currents occurring less than 3 lunar
hours before local highwater. The stronger the currents are,
the greater the tidal amplitude on the east side of the
Inlet than on the west.^
Alaska Department of Fish and Game, Habitat Protection
Section, "Lower Cook Inlet Currents, Tides, Winds, Bathy-
metry and Ice" (map), Anchorage, Alaska, 1976 (unpublished).
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
J.C.H. Mungall, Cook Inlet Tidal Stream Atlas, Institute
of Marine Science, University of Alaska, Fairbanks, Alaska,
1973.
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TABLE A-l
RANGE OF TIDES AND MEAN TIDE LEVEL IN COOK INLET
LOCATION
Ushagat Island, Barren Islands
Port Chatham
Port Graham
SELDOVIA, Kachemak Bay
Homer, Kachemak Bay
Cape Ninilchik
Ninilchik
Kenai River entrance
Kenai City Pier
Nikiski
East Foreland
Fire Island
Sunrise, Turnagain Arn~~
ANCHORAGE, Knik Arm
Eklutna, Knik Arm
North Foreland
Drift River Terminal
Texedni Channel
Snug Harbor
lllamna Bay
Nordyke Island, Kamishak Bay
MEAN
11.4
12.0
14.4
15.4
15.7
16.5
16.7
17.7
17.5
17.9
18.0
24.4
30. 3
26.1
b
18.3
15.4
14.0
13.2
13.2
12.9
RANGES (
DIURNAL
13.7
14.3
16.5
17.8
18.1
19.1
19.1
20.7
19.8
20.7
21.0
27.0
33.3
29.0
b
21.0
18.1
16.6
15.7
14.5
15.2
ft)
MEAN TIDE
LEVEL
7.2
7.5
8.6
9.3
9.5
10.1
10.0
11.0
10.4
11.1
11.2
14.2
17. 1
15.3
b
11.3
9.7
8.9
8.3
7.5
8.0
&A bore frequently occurs in Turnagain Arm just after
low water. Under favorable conditions it is said to reach
a height of 6 feet.
Because of the shoal condition of the upper part of
Knik Arm, the channel off Eklutna becomes practically a
nontidal stream during the period when the height of the
tide at Anchorage is less than 15 feet above mean lower
low water.
Source: National Ocean Survey of the National Oceanic
and Atmospheric Administration, Tide Tables 1976, West Coast
of North and South America, Washington, D.C., 1975, p. 178.
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The currents of Cook Inlet have been described as being
of moderate velocity. In the Forelands region, where the
brine discharge points are located, currents are strongest,
reaching a mean maximum velocity of 3.8 knots, with peak
maximum velocities exceeding 6.5 knots at monthly tidal
extremes. In the Lower Inlet, maximum inward currents
occur 1.5 hours before local high water; in the Upper Inlet
they occur 1.5 to 3 hours before local high water.9 Table A-2
gives the direction of the flood current, the average veloc-
ity of the flood current, the ebb current direction, and the
average velocity of the ebb current, all at strength of
current. Flood and ebb current directions are the direc-
tions toward which the current flows measured in degrees,
clockwise, from 000° at north.
Circulation patterns and tidal currents are important
factors in the distribution of nutrients (hence productivity)
in the Inlet, in determining the impact of localized contami-
nants in the water, and in their effects on unconsolidated
bottom sediment. Depth of water, coastline morphology and
freshwater drainage combine with tidal effects to divide the
Inlet into the three parts which were mentioned earlier.
The Upper Inlet waters are well mixed laterally, longi-
tudinally and vertically with each tidal cycle. In summer,
there is a net outward movement of Upper Inlet waters with
each tidal cycle, due to the large inflow of glacial melt-
water from tributary streams. In winter with the freezing
of these streams, there is no net outflow from the Upper
Inlet and water sloshes back and forth with each tide.10
The Middle Inlet, where brine discharge sites occur, is
characterized by the net inward movement of saline oceanic
waters up the eastern shore and a net outward movement of
freshwater runoff along the western shore. There is exten-
sive vertical mixing due to turbulence from swift current
and high Coriolis force; however, lateral separation of
highly saline incoming water and less saline waters is
maintained throughout the Middle Inlet.H
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
9
Mungall, Cook Inlet Tidal Stream Atlas.
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
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TABLE A-2
MAXIMUM CURRENTS IN COOK INLET
MAXIMUM CURRENTS
LOCATION
FLOOD
DIRECTION AVERAGE
(TRUE) VELOCITY
EBB
DIRECTION AVERAGE
(TRUE) VELOCITY
Chugach Passage
Iniskin Bay
Anchor Point,
3 miles southwest of
Chinitna Bay
Cape Ninilchik,
1 mile west of
Tuxedni Channel
DEGREES
355
000
000
260
020
330
KNOTS
3.
0.
2.
1.
2.
1.
1
9
4
0
2
1
DEGREES
170
180
195
080
205
160
KNOTS
1
1
1
1
1
1
. 8
.2
.9
.1
.4
.9
Cape Kasilof,
3 miles west of 020
Kenai,
6 miles southwest of 020
Kenai Packers Cannery
3.0
2.4
205
195
2.3
2.6
Warf
Nikiski
Nikiski,
0. 8 mile west of
West Foreland, midchannel
Moose Point,
3 miles northwest of
Anchorage,
0.2 mile offshore
Anchorage,
1 mile off of
Knik Arm,
south of Goose Creek
115
000
354
025
065
030
050
015
0.
3.
3.
3.
2.
1.
2.
3.
7
8
8
8
9
5
9
6
285
180
175
205
245
205
220
180
1.
2.
3.
3.
2.
2.
2.
3.
4
6
6
8
6
5
9
9
Source: National Ocean Survey of the National Oceanic and
Atmospheric Administration, Tidal Current Tables 1976, Pacific
Coast of North America and Asia, Washington, D.C., 1975, p. 223.
-238-
-------
In the Lower Inlet, the water masses of differing
salinity maintain separation. On the west side a vertical
stratification occurs with colder saline ocean water under-
lying warmer, less saline inlet waters. Near Tuxedni Bay,
the rising basin floor creates an upwelling of deeper,
oceanic water -- bringing important nutrients up to the
photic zone.12
A.2.6 Salinity
Salinity in Cook Inlet ranges from 32 ppt at the mouth
of the Inlet to 8 ppt at the mouth of the Susitna River in
May.13 Figure A-4 presents surface salinity distribution
in May.
Salinities in the Mid Inlet region, where brine dis-
charge occurs, range from 30 ppt in February to 21 ppt in
August. Saltwater enters the Inlet on the eastern side and
freshwater exits on the western side, a combined result of
the Coriolis force and geographic location of the rivers.14
The waters are well mixed from top to bottom on the
eastern side of the Mid and Upper Inlet. In the Lower Inlet
stratification is observed with the entering cold saline
ocean water underlying warmer Inlet waters.
In areas where large quantities of freshwater are con-
tributed, such as Susitna River, there is a pronounced
halocline and thermocline. However, freshwater inflow from
the Kenai River enters the Inlet in an area of maximum
currents and creates no salinity stratification. Waters
12
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
P.J. Kinney, J. Groves, and D.K. Button, Cook Inlet
Environmental Data, R/V Cruise 065 - May 21-28, 1968,
(College, Alaska: Institute of Marine Science, University
of Alaska, 1970).
14
Kinney, Groves, and Button, Cook Inlet Environmental
Data.
-239-
-------
60° -
Surface Salinity Distribution
COOK INLET
30 nautical miles
(May 1968)
152
150°
Figure A-4. Surface salinity distribution - Cook Inlet,
(P.J. Kinney, J. Groves, and D.K. Button, Cook Inlet Environ-
mental Data, R/V Cruise 065 - May 21-28, 1968 (College,
Alaska: Institute of Marine Science, University of Alaska,
Report No. R-70-2, 1970), p. 13).
-240-
-------
along the western shore have more salinity stratification
due to lesser currents and freshwater input. "Less strati-
fication is observed during flood tides than during ebb
tides.15
For any estuary a key factor determining the rate at
which pollutants are removed from the estuary is the fresh-
water flow into the estuary. Table A-3 gives available data
on the sources of freshwater influx for Upper and Mid Cook
Inlet.
A.2.7 Wind
Wind speed and direction in Cook Inlet show a notable
seasonal variation. In January and February, winds are from
the north at 7 to 40 knots. By April, winds are to the
northwest and have decreased to a maximum of 21 knots. May,
June, and July are very calm, less than 1 knot. Summer winds
have a southerly component and pick up speed in August and
September. In November and December, high velocity (30 knots)
winds blow from the north. Open waters in Cook Inlet tend
to have higher wind speeds than nearshore waters.16
Storms of gale force, with 50 to 75 knot winds, are
experienced in the Cook Inlet each winter. Waves may reach
heights of 15 feet and 6-second periods have been recorded.
Under extreme conditions winds may reach 75 to 100 knots. '
A.2.8 Turbidity and Suspended Sediment
Suspended sediment varies from 0 at the mouth of the
Inlet to 1,540 mg/1 at Anchorage (Figure A-5). These sedi-
ments, often of glacial origin, are derived primarily from
headwaters of the Matanuska River system. Suspended sedi-
ments seem to be uniformly distributed with depth in areas
not immediately in the river plume. Highest values of sus-
pended sediment occur in well-mixed regions of strong tidal
currents — on the east side of the Inlet. Suspended sedi-
ment is nearly absent at the central and western portions
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
Alaska Department of Fish and Game, "Lower Cook
Inlet Currents, Tides, Winds, Bathymetry and Ice."
Alaska Department of Fish and Game, "Lower Cook
Inlet Currents, Tides, Winds, Bathymetry and Ice."
-241-
-------
TABLE A-3
STREAMFLOW DATA, MID AND UPPER COOK INLET
I
to
NAMP np STRFAM DRAINAGE AREA n^rnaSrp
NAMc. Ur blrCbAM . . . OXoLHAKuri
(sq. mi.) (ft3/s)
Susitna R.
near Denali
near Cantwell
near Gold Creek
Tributaries of Susitna
Maclaren R.
Tyone R.
Skwenta R. near Skwenta
Talkeetna R.
near Talkeetna
Chulitna R. near Talkeeta
Matanuska R. at Palmer
Knik R.
Ship Crrek near Anchorage
McArthur R.
Chakachatna R. near Tyonek
Beluga R.
Kenai R. At Soldotna
Source: L.L. Selkregg,
19,400
950
4,140
6,160
280
1,400
2,250
2,006
2,570
2,070
1,200
90.5
350
1,120
930
2,010
Alaska Regional
2,665
6,824
10,250
1,092
—
6,937
5,299
8,406
4,196
5,800
149
—
4,658
—
5,958
Profiles;
MAXIMUM MINIMUM
DAILY DAILY
DISCHARGE DISCHARGE
(ftVs) (ft3/s)
__
—
55,000
77,700
8,200
—
47,500
63,000
45,000
40,700
—
1,420
—
90,000
—
23,900
South Central Region
—
460
950
55
--
600
400
900
360
—
0
--
460
—
1,100
(Anchorage:
University of Alaska, Arctic Environmental Information and Data Center, 1974), pp. 87,90
-------
Suspended Sediments
Average Value for Stations in mg/l
COOK INLET
60° -
30 nautical miles
MAY
Figure A-5. Suspended sediments - Cook Inlet. Average
value for stations in mg/l. (P.J. Kinney, J. Groves, and
O.K. Button, Cook Inlet Environmental Data, R/V Cruise 065 -
May 21-28, 1968 (College, Alaska: Institute of Marine
Science, University of Alaska, Report No. R-70-2, 1970), p. 23
-243-
-------
of the Inlet mouth. Organic carbon and silicate concentra-
tions follow the same patterns as do suspended sediment.18
A. 2 . 9 -Bottom Sediments
Lower Cook Inlet bottom sediments consist of silty sand
and gravelly sand; Mid Inlet sediments are primarily gravel;
and Upper Inlet sediments contain well-sorted sand (Figure A-6)
Little deposition of sediments takes place in the Upper Inlet
though much of the flocculation may be deposited on the exten-
sive mudflats north of the Forelands.19
A.2.10 Biology — Cook Inlet Open Waters
The distribution of plants and animals in the Cook Inlet
waters reflects the complex interactions of tidal mixing of
fresh and salt waters, the large tidal amplitude resulting
in extensive tidal flats, the large loads of suspended glacial
sediments, the scouring action of tidal currents, and the
presence of ice during winter months.
Little is known about the distribution and abundance of
benthic species in Cook Inlet. It appears that very few
species exist in the silt laden waters of the western and
upper half of the Inlet. The high tidal amplitude and strong
tidal currents which scour the bottom make survival difficult
for most benthic organisms. The great loads of suspended
sediment in these regions limit penetration of light, con-
fining photosynthesis to a very shallow photic zone. Pro-
ductivity seems to increase as one moves oceanward in the
Inlet to clearer, more saline waters. The Lower Inlet waters
provide habitat for a variety of sport and commercially im-
portant fish and shellfish, and numerous other non-fished
species.
A.2.11 Primary Productivity
Most primary production in the open waters of Cook
Inlet occurs in the form of phytoplankton. The high silicate
content of incoming sediments and of Inlet waters seems to
favor the growth of diatoms, which appear to be the dominant
1 o
Kinney, Groves, and Button, Cook Inlet Environmental
Data.
19
Anderson, Gatto, McKim, and Petrone, "Sediment Distri-
bution and Coastal Processes in Cook Inlet"; and Kinney,
Groves, and Button, Cook Inlet Environmental Data.
-244-
-------
60°
COOK INLET
BOTTOM SEDIMENTS
LEGEND:
I) * * J sand
sandy gravel & gravel
gravelly sand with
silt & clay components
154"
152'
150«
Figure A-6. Bottom sediments - Cook Inlet. (P.J. Kinney,
J. Groves, and O.K. Button, Cook Inlet Environmental Data, R/V
Cruise 065 - May 21-28, 1968 (College, Alaska: Institute of
Marine Science, University of Alaska, Report No. R-70-2,
1970), p. 24.
-245-
-------
phytoplankton. The presence of silicoflagellates, dino-
flagellates and tintinnids have also been reported.20
It is quite possible that the majority of the phytoplankton
consists of nanno and ultra plankton, which are too small to
accurately collect and identify generically. Table A-4
presents the major identifiable primary producers in the
open waters of Cook Inlet.
The rapid exchange of water with the Gulf of Alaska and
strong vertical mixing on the lower east side of the Inlet
support the growth of numerous diatoms and macrophytes.
There are more species of primary producers found in this
region than in the Mid and Upper Inlet, where higher tur-
bidity, brackish water and less nutrient turnover limit
photosynthesis. Diatom blooms, which occur periodically,
are limited by light intensity and by nitrogen and silica
concentrations in the water. In the Lower Inlet, macrophtyic
algae (kelp) (see Table A-4) found in subtidal and inter-
tidal waters provide food, shelter and living substrate for
epifaunal organisms. They also serve as nursery grounds for
fish and as wave dampeners and tethers for floating mammals
and birds.21
Productivity in the Mid Inlet, while greater than that
in Upper Inlet waters, is considerably less than in the
lower portion of Cook Inlet. Phytoplankton is the only
primary producer and the combination of strong currents,
severe ice conditions in winter and high suspended sediment
loads in summer, limits rates of photosynthesis. This in
turn affects the number and types of heterotrophic species
which can be supported in the Mid Inlet.
A.2.12 Consumers
Zooplankton of Cook Inlet have not been studied in
great detail, but representatives of the phyla Protozoa,
Coelenterata, Ectoprocta, Nematoda, Annelida, Mollusca,
Rotifera, Chordata, and Arthropoda have been found in Inlet
20
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
21
U.S. Fish and Wildlife Service, Office of Ecological
Services, Resources Assessment Lower Cook Inlet (unpublished),
Anchorage, Alaska.
-246-
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TABLE A-4
PRIMARY PRODUCERS - COOK INLET
INTERTIDAL
(MUDFLAT AND GRAVEL)
NEAR OFFSHORE WATERS
FAR OFFSHORE WATERS
I
K)
MACROPHYTIC ALGAE
*Ulothrix laetevirens
*Enteromorpha intestinalis
*Enteromorpha compressa
*U)va lactuca
DIATOMS
MACROPHYTIC ALGAE
*Melosira sulcata
*Cocconeis scutellum
*Biddulphia aurita
*Asterionella kariana
*Fragilaria sp.
Laminaria sp.
Fucus sp.
Alaria sp.
Nereocystus sp.
DIATOMS
*t'flosira sulcata
*Biddulphia aunta
*Coscinodiscus sp_-
*Coscinodiscus linoatup;
*Coscinodiscus oculus-iridus
*Coscinodiscus stellarif.
*ActinoptYchus sp.
*ftctinoptychus undulatus
*Frgcjilar3 a sp^
'Cocconois sp.
*Coccohois scutolliun
*Dit^luin br irjhtwo] 11 i
*Cyc_lotal_la sp_._
*Astcr]onolla spL
*Astcrionolla k.i
NOTE:
'indicates species found in Mid inlet.
-------
22
waters. These species graze on the phytoplankton species
listed in Table A-4.
The Cook Inlet (primarily the lower portion) provides a
suitable habitat for all the commercially harvestable species
in Alaska and for most of the sport species.23 Table A-5
presents some of the key consumers in Cook Inlet. The
important shellfish harvested include three species of
crabs, five shrimp species, razor clams and scallops. The
crab and shrimp species are primarily detritivores, feeding
on newly dead animal material and occasionally on live
amphipods or polychaetes. The clams and scallops feed by
filtering planktonic material and organic particulate matter
out of the water column.
The principal fish caught in Cook Inlet are salmon,
steelhead, Dolly Varden, halibut, herring, and smelt.24
Five species of Pacific salmon (Oncorhyncus) are found in
Cook Inlet and associated rivers and lakes. The pink salmon
are most abundant; sockeye, chum and coho salmon are of
intermediate abundance; and Chinook salmon are least
numerous. 5 Other finfish species caught in deep waters
include butterfish, sole, yellowfin and pollock.
There are several migratory patterns which can be
observed among fish and shellfish of Cook Inlet. Many of
the important commercial and sport species are anadromous.
They spend most of their life in Cook Inlet and return to
freshwater coastal streams and rivers to spawn. In most
anadromous species the adult dies after spawning. The fry
develop in streams and after hatching may either migrate
directly to the ocean (as do pink salmon) or may migrate to
a lake entering the ocean later as a juvenile (as do sockeye
salmon). Salmon, Dolly Varden, steelhead, grayling and
22
Evans, Buck, Buffler, et al., Cook Inlet Environment,
Study of Available Knowledge.
Alaska Department of Fish and Game, Habitat Protection
Section, "Lower Cook Inlet Fisheries" (map), Anchorage,
Alaska, 1976 (unpublished).
24
U.S. Fish and Wildlife Service, Resources Assessment
Lower Cook Inlet.
Frank Stefanich, Resources Inventory, South Central
Region; Fisheries Resources, Resources Planning Team,
Joint Federal-State Land Use Planning Commission, Alaska,
1974.
-248-
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TABLE A-5
KEY CONSUMERS - COOK INLET
NEAR AND FAR OFFSHORE WATERS
INVERTEBRATES
FISH
BIRDS
MAMMALS
COMMERCIAL * it Paralithodes camtschatica
SPECIES (King Crab)
if if Chionecetes bair?s
(Tanner Crab)
if if Cancer magister
(Dugeness Crab)
• if Patinopectcn caurinus
(Scallops)
if if Pandalus borealis
(Pink Shrimp)
•fr if Pandalus hypsinotus
(Coonstripe Shrimp)
if if Pandalus goniurus
(Humpy Shrimp)
if if Pandalus dispar
•ir Oncorhynchus gorbuscha*
(Pink Salmon)
if Oncorhynchus shawytscha*
(Chinook Salmon)
if Oncorhynchus keta
(Chum Salmon)
if Oncorhynchus kisutch*
(Coho Salmon)
if Oncorhynchus nerka*
(Sockeye Salmon)
if Clupea pallasii*
(Herring)
(Sidestripe Shrimp)
SPORT SPECIES
Pandalus platyceros
(Spot Shrimp)
if Salmo gairdneri*
(Steelhead)
if Salvelinus malma*
(Dolly Varden)
if HippoqlQSSus stenolipis*
(Halibut)
if Thaleichthys pacificus*
(Smelt)
if Salmo gairdneri
(Steelhead trout)
it Atheresthes s'tomias
(Flounder)
if it Gadus macrocephalus
(Cod)
if Enhydra lutria
(Sea Otter)
ir Phoca vitulina
(Harbor Seals)
if Detritivore
^ Carnivore
• Herbivore
NOTE: An asterisk {*) indicates species found in Mid Inlet.
-249-
-------
TABLE A-5 (CONT.)
INVERTEBRATES
FISH
BIRDS
MAMMALS
TROPHICALLY
IMPORTANT
SPECIES
ENDANGERED
SPECIES
Thuriaria sp.* •& Melanitta perpicillata
(Hydrozoan) (Surf Scooter)
it Autolytus sp. (Larvae) £ Larus hyperboreus
(Polychaete) (Glaucous-winged Gull)
• Acartia sp.* ^ Larus sp.
(Copepod) (New Gull)
• Eurytemora sp.* -fr Rissa sp.
(Copepod) (Black Legged Kittiwake)
• Nauplius (Larvae)* -fa sterna paradisaea
(Copepod) (Arctic Turn)
• Pseudocalanus sp.*
(Copepod)
• •*• Balanus sp. (Larvae)*
(Barnacle)
•ft Lamprops sp . *
(Cumacae)
•ft Crago sp. *
(Decapod)
T& Pagurus sp. *
(Decapod)
Sagitta elegans*
(Chaetognath)
•tfr Eumysis sp. *
(Mysid)
• Discorbes sp.*
(Foraminifera)
• Strongylocentrotus droba- ''
chiensis (Sea Urchin)
•fr Thais lamellosa
(Dog Walk)
*-kir Delphinapterus leucas
(Beluga Whales)
* Detritivore
if Carnivore
• Herbivore
NOTE: An asterisk (*) indicates species found in Mid Inlet.
-250-
-------
smelt are all anadromous fish which are caught at the mouths
of rivers and streams where they congregate before migrating
into freshwater.26
Other species spend their entire existence in the
saline waters of Cook Inlet, migrating toward shore and into
deeper waters at different stages in their life cycle.
Pandaeid shrimp, king crabs, snow crabs, weathervane scal-
lops and halibut hatch in deep waters, spend several weeks
or months as planktonic larvae, move inshore (to depths less
than 50 fathoms) to take up a semi-benthic existence as
juveniles, and migrate back to deeper waters as adults. In
an opposite pattern, herring spawn in nearshore subtidal and
intertidal waters, laying their eggs on living plants. The
larvae mature in shallow waters and as juveniles they group
in small schools and move out to sea. The dungeness crab
also spends its larval life in shallow waters, often in
intertidal stands of eel grass, and moves offshore as an
adult.
Many Cook Inlet species have annual inshore-offshore
migration patterns which may be associated with life history
stages, but are often induced by seasonal changes in water
temperature and ice cover.
Though many of the species mentioned above are found
predominantly in the Lower Inlet, king, sockeye, coho and
pink salmon, Dolly Varden and steelhead trout all spawn in
rivers and streams of the Mid Inlet. The Kenai River is an
extremely productive spawning ground for these species.
A variety of marine mammals inhabit the entire coastal
region of Cook Inlet, but they breed on the islands of the
Lower Inlet. Sea otters and harbor seals are found on the
west side of the Inlet and in Kachemak Bay. Sea lions
concentrate on the barrier islands south of Cook Inlet, and
Beluga whales swim up the Inlet as far as the Susitna River.
Killer whales and Dali porpoises are also commonly observed
in the Lower Inlet.27
A simplified food web for Cook Inlet waters, involving
many of the species discussed here is displayed in Figure A-7
2 6
Stefanich, Resources Inventory, South Central Region:
Fisheries Resources.
27
M.P. Wennekens, L.B. Flagg, L. Tratsky, et al.,
Kachemak Bay, A Status Report (Anchorage: Alaska Department
of Fish and Game, Habitat Protection Section, December 1975),
-251-
-------
I
NJ
cn
NJ
I
LITTORAL FEEDING BIRDS*
BOTTOM
BENTHIC
LIGHT
MAN
Depth
Meters
-0
PHYT.OPLAN.KTON
DETRITUS
Pocific Holibut
J Pocific Cod
^ Alaskan Pollock
^r3 Sockeye Salmon
^J Chum Salmon
^ Pink Salmon
C^ Dolly Varden
^1 Rock Greenling
O' Pacific Ocean Perch
-x° Sole and Flounders
ns» Lolernfish
O» Larval Rockfish
— Small Fish, Primarily Pacific Sand Lance
^ Amphipods
•**i Other Small Crustaceans (Euphausiids, Cumaceans, Copepods)
^ Meteropods and Pteropods
*• Briltlestars
iff Miscellaneous Worms
4- Sea Urchin
*-s Mysids
Figure A-7. Cook Inlet food chain. (L.L. Selkregg, Alaska Regional
Profiles; South Central Region (Anchorage: University of Alaska, Arctic
EnvironmentalInformation and Data Center, 1974), p. 153.)
-------
A.2.13 Biology - Cook Inlet Intertidal Region
Cook Inlet is bordered by a variety of community types.
Tidal marshes, mudflats, and rocky shores dominate the Mid
and Upper Inlet; rocky coastline, fjords and cliffs dominate
the Lower Inlet. One hundred square miles of tidal marshes
are found in the Susitna Flats, Chickaloon Flats, Trading
Bay and Redoubt Bay in the Upper and West Mid Inlet. These
areas support high densities of waterfowl.
The onshore separation facilities at Nikiska and just
below Kenai on the east side of the Mid Inlet, are located
along coasts characterized by upland spruce-hardwood forests.
These forests extend almost directly down to the shoreline,
and are separated from the water by a small drop (50 feet)
and some gravel and rocks. The diversity of species occu-
pying the intertidal region in these areas is considerably
less than in the Lower Inlet. A study performed by the
University of Alaska for the Collier Carbon and Chemical
Corporation, in May 1968, reported only five species of green
algae on the Nikiska shoreline. Most of the faunal organisms
found were relatively sessile, attached to rocks or burrowing
in gravelly sand. These included hydrozoans, flatworms,
coelenterates, brachiopods, amphipids, isopods, clams, snails,
barnacles, limpets, polychaetes and pycnogonids (sea spiders).
A total of 46 taxa were reported in this study.28 Table A-6
presents the most important of these.
The two onshore separation facilities on the West Mid
Inlet are located at Granite Point and near West Foreland
in tidal marsh and swamp communities. Marsh grasses and
waterfowl are the dominant species. These areas are also
part of an important bald eagle migration route.29
The Collier Carbon Study referred to here is one of the
only studies which has sampled organisms from Mid Inlet
intertidal zones. There are few roads and most observations
of biota seem to have been made by air. As mentioned in the
introduction to this section, the lack of data makes a com-
plete onshore characterization of the discharge sites (par-
ticularly the western sites) impossible.
2 8
Hood, Natajan, Rosenberg, and Wallen, Summary Report
on Collier Carbon and Chemical Corporation.
29
L.L. Selkregg, Alaska Regional Profiles; South Central
Region (Anchorage: University of Alaska, Arctic Environ-
mental Information and Data Center, 1974) .
-253-
-------
TABLE A-6
KEY CONSUMERS - COOK INLET
INTERTIDAL (MUDFLAT - ROCKY)
COMMERCIAL
SPECIES
SPORT SPECIES
TROPHtCALLY
IMPOPTAHT
SPECIES
ENDANGERED
SPECIES
INVERTEBRATES
•*• Siliqua patula*
(Razor Clam)
it Siliqua patula*
(Razor Clam)
. An^ojsp.™. M,.
(xjr.phipod)
t Gamnarus wilkitzskii*
(Anpnipod)
(Clami"
(Barnacle)
• Idotef;4 entomon*
(Irupod)
• Littonna sp_.«
(Snail)
• Acnna SF-*
(Limpet)
•ft Buccxnium sp. *
(Dog whelk) "
•fr-fr Cancer niagister*
(Crab)
•AEvastorias trochelii
(Soa star)
•fa Thais lamellosa
(Srail)
ir4t Telnmcsaus ch«lragonus
(Horse Crab)
& Pycnopodia sp.
(Sea Star)
BIRDS
•fr Fraterula sp.
(Puffin)
ir Piss,a sp.
(Kittiwake)
•(r Uria sp.
(Muire)
•fr Phalacrocorax sp.
(Cormorant)
tf Lurus) sp.
(dull)
T^Haliaeetus leucoccphal \s_
(Bald Eagle)
MAMMALS
• Alces alcss
( Moose )
• Fangifer tarandusgranti
(Caribou)
if Lutra canadensis
(Otter)
if Detntivoce
•&• Carnivore
• Herbivore
NOTEt An asterisk (*) indicates species found in Mid Inlet
-254-
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A.3 Gulf of Mexico Characterization
A.3.1 Introduc tion
The study site in the Gulf of Mexico encompasses the
marshes and nearshore waters of Barataria Bay, Timbalier
Bay, and Terrebonne Bay in Louisiana, and the offshore
waters adjacent to these Bays. These bays are part of a
larger drainage basin system which divides Louisiana into
distinct hydrologic units. The study area is depicted in
Figure A-8.
The Barataria drainage basin encompasses 1,900 square
miles (1,216,000 acres) of land and water-^0 ancj is bordered
by the Mississippi River on the east and Bayou Lafourche on
the west. The drainage basin encompassing Terrebonne and
Timbalier Bays, bordered by Bayou Lafourche on the east and
the Houma Navigation Canal on the west, contains 597,900
acres of land and water.3^
The two drainage basins are morphologically, physi-
cally, chemically and biologically similar. Both regions
are composed of a large estuarine waterbody separated from
the Gulf of Mexico waters by a string of barrier islands,
Grand Island, and Grand Terre Islands in Barataria Bay, East
Timbalier Island, Timbalier Island, Wine Island and Dernieres
in Timbalier and Terrebonne Bays. Both these estuarine
regions are bordered by an intricate system of salt marshes
and bays, extending northward into brackish and freshwater
marshes, lakes and bayous. These two estuarine systems are
similarly influenced by Gulf currents, by the Mississippi
outflow and by freshwater and tidal inundation.
The offshore Gulf waters adjacent to Barataria Bay are
also very much like those waters adjacent to Timbalier and
Terrebonne Bays. They receive similar hydrologic and organic
input from the nearshore and marsh areas, and from the Mis-
sissippi River. They experience the same meteorologic
conditions and have a similar physical and biological regime.
Barney Barrett, Water Measurements of Coastal Louisiana
(New Orleans: Louisiana Wildlife and Fisheries Commission,
Oyster, Water Bottoms and Seafood Division, 1970).
Barrett, Water Measurements of Coastal Louisiana.
-255-
-------
U1
cr\
I
ISLES
Fiqure A-8. Barataria - Timbalier - Terrebonne Bay area.
-------
Both the Barataria and the Timbalier-Terrebonne nearshore-
offshore systems are of interest in this study, but because
the hydrologic, chemical and geologic features, and resulting
vegetation and associated fauna are alike in these two
systems, only one of these, the Barataria Bay and adjacent
Gulf system, will be discussed in depth in this characteri-
zation. The first section will describe Barataria Bay, its
marshes and associated waterbodies. The second section
discusses the near offshore and far offshore waters in the
Gulf of Mexico adjacent to Barataria Basin.
A.3.2 Barataria Bay
The areas dealt with in this section of the characteri-
zation are the brackish and salt marshes and their associated
waterbodies. This includes a number of lakes, Barataria Bay
and Caminada Bay. Approximately 1,150,000 acres of the
Barataria Basin are wetland and 66,000 acres are water.
Sixty-six percent of the wetlands are freshwater marsh and
swamp (salinity 0 to 5 ppt), 20 percent are brackish marsh
(salinity 5 to 13 ppt), and 14 percent are salt marsh (sali-
nity 13 to 30 ppt).32 Figure A-9 displays the distribution
of these wetland communities in Barataria Basin.
A.3.2.1 Temperature
Average surface water temperature in Barataria Bay is
approximately 22° C, with monthly averages ranging from a
high in August of 29.5° C to a low in February or March of
13° C. During a 12-year period (1958-1969) the temperature
extremes, measured by a continuous recorder at Ft. Livingston
(near Barataria Pass), have ranged from 0° C to 36° C.
Warming of Barataria waters begins in February or March and
continues through August; cooling trends begin around Sep-
tember, though this may vary in unusually warm or cool
years.
32
L.M. Bahr and J.J. Hebrard, Barataria Basin: Biolog-
ical Characterization (Louisiana State University, Center
for Wetland Resources, 1976), unpublished.
Louisiana Wildlife and Fisheries Commission, Cooper-
ative Gulf of Mexico Estuarine Inventory and Study, Phase
II Hydrology, New Orleans, 1971
-257-
-------
;L^m
___ v^S^gBfsjKi
•* _ * ** T^—i . * * * \- . ?» - *** *, -"" - ~"1-~ ~_ I:.—.'-_ <*? ^^^il^K. Pv * B»^^ *&*^ r jT^tC*^— —^^l /,' i-^~~^ ~TTS "*J t;*i.". "^i. r~~1
• '. • « •» * * , • \ »* ,».-*. » • — — - -—* ^ *-r % O t> T Nrf^' -,. —•^ - ——, \ H U —•* ••• • -^"*- —-^J ^> w—^1
eESfc
%cgp::;-> i^^->£
GRAND ISLE
, .A J^f^-f" V'^-^^^^-^c/
=isS f -^7>:-±~: • -^..-^^c^C:}^--^?.
FRESH MARSH
(0-5 ppt.)
MARSH
(6-13
SALT MARSH
(H-30 ppt.)
Figure A-9. Barataria Bay narsh types. tS.H.
et al., "Environmental Atlas and Multiuse Management Plan for
South Central Louisiana," Hydrologic and Geologic Studies
of Coastal Louisiana, Report 18, Vol. 2, plate 8 (Baton
Rouge: Louisiana State University, Center for Wetland
Resources, 1973).
-258-
-------
The southern waters of Barataria Bay are warmer in
winter months than northern bay waters; however, in the
spring water temperatures are a few degrees higher in the
north bay. Top and bottom temperatures rarely differ more
than one degree in Barataria Bay, due to the shallow depths
and mixing action of waves and currents. In the winter
surface water temperatures are slightly lower than bottom
water temperatures, while the reverse is true in summer.
Figure A-10 depicts a summer isotherm profile across the
middle of the bay.
A.3.2.2 Depth34
The Barataria-Caminada Bay water system (which will be
referred to as one unit), occupies 57,709 acres and a volume
of 275,002 acre-ft. This estuary is extremely shallow, most
of it is less than 4 feet in depth. The following list
describes the depth patterns of the Barataria-Caminada
system.
DEPTH
(ft)
1
4
7
10
0-
.5
.5
.5
.5
1.5
- 4.5
- 7.5
-10.5
-50
BARATARIA BAY
(acres)
10,771
28,982
2,553
685
560
CAMINADA BAY TOTAL
(acres) (acres)
13,413 24,184
541 29,523
204 2,757
685
560
34
Barrett, Water Measurements of Coastal Louisiana
-259-
-------
O
I
s
PC
•*•
w
5
t. Marys l\ i d d I e B a n k Inclspe
> i n t ~Vfcfor Surface Light 1 s 1 G
i/ 30.730.6:50.5
x--~"-^ N^.^''XX /
^^ ^^*^* **"»i»_ *~— • ^X^ ^^
^ ^^- " ^^^
^^- "^^
^..x-
x^ •'•
^*"x*fc i-r __, nri— --
~~^ -^ "\ „ • ' , . . .__ '
\ M^^ 30.4
/
/
'
.X o
^ -D
s~ ~ $ ~
-r\
o
a>
J/=3ii'
\
Water £ o 11 o r.%
' - 10 ~
Figure A-10. Isothe_rm profile in degrees centriarade alonq a north-south line in
Barataria Bay on August 8, 1967. Distance between Grand Terre and St. Marys Point
is 10 miles. (Louisiana Wildlife and Fisheries Commission, Cooperative Gulf of Mexico
Estuarine Inventory and Study, Louisiana, Phase II Hydrology, 1971, p. 46).
-------
A.3.2.3 Tides and Currents
The normal tide along the Louisiana coast is diurnal
though these are subject to the effects of changing metereo-
logic conditions, such as strong winds or barometric pressure
North winds lower water levels, lengthen the duration of
ebbing tides and reduce the range of flooding tides, while
southerly winds have the reverse effect.
The average annual tidal range near the mouth of Bara-
taria Bay is 13.3 inches. Most of the Louisiana coastline
experiences an average tidal range near 1 foot. Neap tides
range from 3 to 4 inches, while spring tidal ranges average
almost 2 feet. One of the highest tides recorded was 91.0
inches during hurricane Betsy (September 9, 1965) and the
lowest was -25.7 inches, recorded during a strong north-
northwest wind (December 21, 1960). Table A-7 gives the
diurnal range (the difference in height between mean higher
high water and mean lower low water), and the mean tide
level (the plane midway between mean low water and mean high
water measured from the mean low water level) at selected
locations along the Louisiana coast.
Gulf waters enter Barataria Bay through Barataria Pass,
Pass Abel, Quatre Bayoux Pass and Caminada Pass. Flooding
waters are normally reflected to the western side, by the
earth's rotation.
Water circulation in Barataria Bay is primarily tidal.
Tidal currents are strongest at the moon's maximum decli-
nation, with a velocity between 2 and 3 knots. The velocity
is greatest just below low and high tides, with slack tidal
currents occurring just after low and high water. The
current in Barataria Pass continues to ebb for a short time
after low water (while the tidal height is rising) and
continues to flood just after high water (while the tide is
falling). Table A-8 gives the direction of the flood
current, the average velocity of the flood current, the ebb
current direction, and the average velocity of the ebb
J.G. Gosellink, R.R. Miller, M. Hood, and L.M. Bahr,
^r•' Louisiana Offshore Oil Port: Environmental Baseline
Study/ Vol. II (Baton Rouge: Louisiana State University,
Center for Wetland Resources, 1975); and Louisiana Wildlife
and Fisheries Commission, Cooperative Gulf of Mexico
Estuarine Inventory and Study.
-261-
-------
TABLE A-7
RANGE OF TIDES, AND MEAN TIDE LEVEL
ALONG LOUISIANA COAST
LOCATION
Bastian Island
Quatre Bayoux Pass3
Barataria Passa
RANGE
DIURNAL
1.2
1.3
1.2
(ft)
MEAN TIDE
LEVEL
0.6
0.6
0.6
Barataria Bay
Bayou Island, Grand Isletc
Independence Island
Manilla3
Caminada Pass (bridge)
Timbalier Island,
Timbalier Baya
Pelican Islands,
Timbalier Baya
Wine Island, Terrebonne Bay'
Caillou Bocaa
Raccoon Point, Caillou Baya
Ship Shoal Light3
1.0
0.9
1.0
0.9
1.2
1.2
1.3
1.4
1.7
1.6
0.5
0.4
0.5
0.4
0.6
0.6
0.6
0.7
0.8
0.8
Tide is chiefly diurnal.
Source: National Ocean Survey of the National Oceanic
and Atmospheric Administration, Tide Tables 1976, East Coast
of North and South America, Washington, D.C., 1975, p. 236.
-262-
-------
TABLE A-8
MAXIMUM CURRENTS ALONG LOUISIANA COAST
MAXIMUM CURRENTS
FLOOD
EBB
DIRECTION DIURNAL DIRECTION DIURNAL
LOCATION (TRUE) VELOCITY (TRUE) VELOCITY
DEGREES KNOTS DEGREES
Quatre Bayoux Pass,
Barataria Bay
Pass Abel,
Barataria Bay
Barataria Pass,
Barataria Bay
Barataria Bay,
1.1 miles NE of Manilla
Caminada Pass,
Barataria Bay
Seabrook Bridge,
New Orleans
Cat Island Pass,
Terrebonne Bay
Wine Island Pass
Caillou Boca,
Caillou Bay
Calcasieu Pass
Calcasieu Pass,
35 miles south of
Calcasieu Pass,
67 miles south of
Source : National Ocean
Atmospheric Administration,
290
315
315
355
295
350
015
325
095
020
WEAK
1.
0.
1.
0.
1.
1.
1.
1.
1.
1.
2 105
9 145
5 120
4 160
5 120
2 170
1 195
7 160
3 265
7 205
KNOTS
1. 3
1.6
1.3
0. 5
1.5
0.9
1.5
1.9
0.7
2.3
AND VARIABLE CURRENT
Survey of the National Oceanic and
Tidal Current Tables 1976, Atlantic
Coast of North America, Washington, D.C.,
1975, p. 165.
-263-
-------
current, all at strength of current, for the Barataria-
Caminada Bay passes and other selected locations along the
Louisiana coast.
The volume and velocity of ebbing waters through the
barrier island passes is usually greater than that of the
flood tide due to freshwater drainage from the north (Table
A-9). As a result, the western sides of the passes are much
deeper than the eastern sides. Barataria Pass is 160 to 190
feet deep on the west and 10 to 20 feet deep on the east
side.
A.3.2.4 Salinity36
The salinity regime of Barataria Bay changes seasonally
and annually as a function of freshwater flow into the bay,
rainfall, saltwater intrusion via tides and storm surges.
The bay itself is a broad freshwater-saltwater mixing
zone, characterized by low salinity gradients. Freshwater,
originating as overflow from the Mississippi River and its
tributaries, and by precipitation surpluses, is stored in
the marsh-swamp environment, and numerous lakes of the upper
estuary, and is gradually released seaward. Much of the
freshwater drains from the northwest, mainly through Bayou
St. Denis and Grand Bayou, and moves down the west side of
the bay. Thus, salinities are higher in the east and
northeast sectors of Barataria Bay.
Saltwater influx is dictated by tidal range, seasonal
wind patterns, shape and size of the estuarine tidal prism,
and size and number of tidal passes between barrier islands.
The salinity of water entering Barataria Bay through passes
which open into the Gulf of Mexico, changes as a function of
Mississippi River discharge and offshore circulation.
Gosselink, Miller, Hood, and Bahr, Louisiana Offshore
Oil Port; C.L. Ho and B.B. Barrett, Distribution of Nutrients
in Louisiana Coastal Waters Influenced by the Mississippi
River, Technical Bulletin No. 17 (New Orleans: Louisiana
Wildlife and Fisheries Commission, Oyster, Water Bottom and
Seafood Division, 1975); and Louisiana Wildlife and Fisheries
Commission, Cooperative Gulf of Mexico Inventory and Study.
-264-
-------
TABLE A-9
FLOOD AND EBB FLOW THROUGH THE
FOUR MAJOR PASSES
OF BARATARIA AND CAMINADA
BAYS
(Mft3)
PASS
Barataria
Quatre Bayoux
Caminada
Abel
TOTAL
FLOOD FLOW EBB FLOW EBB EXCESS
3,229 3,438
874 1,005
627 653
129 212
4,859 5,308
209
131
26
83
449
Source: Louisiana Wildlife and Fisheries Commission,
Cooperative Gulf of Mexico Estuarine Inventory and Study,
Louisiana, Phase II
Hydrology, 1971, p. 57.
-265-
-------
Surface salinities in Barataria Bay vary from a low of
5 ppt in the upper reaches of the estuary (North of Saturday
Island) to 25 ppt or more as one nears the Gulf of Mexico.
Figure A-ll depicts average surface isohalines for Barataria
Bay. During ebbing and rising tides the waters in Barataria
Bay become less saline and more saline, respectively, thus
diurnal variation in salinity is observed.
Fluctuations in normal salinity patterns are observed
during periods of high river discharge. Freshwater from the
mouth of the Mississippi follows the Louisiana coastline
from east to west, diluting coastal salinities. These
waters enter Barataria Bay and may extend northward up to 10
miles, causing a decrease in salinity conditions from
normal levels. Dilutions also occur as a result of increased
freshwater flow of bayous and rivers directly entering
Barataria Bay.
Salinity stratification and salt wedges are kept at a
minimum in Barataria Bay by shallow depth, tidal action,
winds and heavy boat traffic. However, in several areas,
near Independence Island and just north of Middle Bank
Light, there are steep surface salinity gradients. During
periods of very high river discharge the differences between
top and bottom waters may vary up to 5 ppt. Figure A-12
displays a salinity profile of Barataria Bay along a transect
from Grand Terre to St. Marys Point.
A.3.2.5 Winds37
Strong northerly winds occur in Barataria Bay from fall
to early spring, striking with speeds up to 30 to 40 miles
per hour. The velocity decreases to 15 to 20 miles per hour
after passage of the front and the winds may persist for
three or four days. These winds, called Northers, are
accompanied by rainfall when there is a rapid drop in
temperature. High barometric pressure combined with these
north winds results in extremely low water levels. The
water piles up along the northern shores of Grand Isle and
Grand Terre as the passes are unable to transport windblown
water out into the Gulf as rapidly as it accumulates. This
lasts only briefly, then the waters of the bay and Gulf
begin to flow in the same direction, lowering the water
levels of the bay.
Gosselink, Miller, Hood, Bahr, Louisiana Offshore Oil
Port; and Louisiana Wildlife and Fisheries Commission,
Cooperative Gulf of Mexico Estuarine Inventory and Study.
-266-
-------
10
^
Figure A-ll. Isohaline map of Barataria Bay. (Fred Dunham,
Study of Important Estuarine Dependent Fishes, Technical Bulletin
No. 4 (New Orleans: Louisiana Wildlife and Fisheries Commission,
Oyster, Water Bottoms and Seafood Division, 1972), p. 7.)
-267-
-------
cr>
CX3
St. Marys Middle Bark Independence G r a
Point /-Water Surface Li
{f*\ / t a *** /**
O / 15 ^ 0
, /' / ' J
1 1 f j i ////////
' ' I 1 '//•'////
/' /,///////
'I I/ l / f ' / ' /
1*1 f • * • /
1 1 ' / / / / 7 / / 7
'/ (./»./ / , //////
ght Jolond. Ter
2526 E7 2829 28 27 26
11 1 J 1 I
/ ''//'/'/ / i j
1 1
/ 1
' /" / I ' '
/ / ' / / /
'//' / / / '
' , / f 1 '
x / / i
' |
' |
' I-
n d
r e
o
a>
Tl
5 -
•y
•n
a
o
Figure A-12. Salinity profile of Barataria Bay. Numbers are in parts per thousand.
Data taken on August 8, 1967. Distance between Grand Terre and St. Marys Point is 10
miles. (Louisiana Wildlife and Fisheries Commission, Cooperative Gulf of Mexico
Estuarine Inventory and Study, Phase II Hydrology, 1971, p. 51.)
-------
Winds also have an important effect on salinity.
Strong southwest to west winds reduce the westward drift of
river water entering the bay, increasing salinities in the
lower estuary and near offshore areas, while east to south
winds bring river water into the area resulting in lowered
salinities in the lower estuary.
From September to February the prevailing winds are
north to northeast, from April to August they are from
southeast to southwest. The most infrequently occurring
winds are from the southwest to northwest.
00
A.3.2.6 Turbidity
Barataria Bay waters are quite turbid due to freshwater
drainage, tidal mixing action and the influence of the
Mississippi River. The average visibility for a 1968-1969
study was 1.9 feet with extremes ranging from 3.7 to 0.9
feet. Turbidities were higher in the upper estuary and
decreased towards the Gulf. Turbidity does not vary con-
sistently with salinity, but seems to fluctuate directly
with total phosphorus concentrations.
39
A.3.2.7 Sediment Chemistry
Sediments in Barataria Bay are contributed mainly by
the Gulf of Mexico, the Mississippi River, erosion of the
wetlands, and drainage waters from north of the Bay. Clayey
silt is the dominant sediment type, found along the boundaries
of the bay. The sediment becomes more silty towards the
marshes, and more sandy towards the Gulf side of the bay.
3 8
Gosselink, Miller, Hood, Bahr, Louisiana Offshore Oil
Port; and Louisiana Wildlife and Fisheries Commission, Coopera-
tive Gulf of Mexico Estuarine Inventory and Study.
39
C.L. Ho and J. Lane, "Interstitial Water Composition in
Barataria Bay (Louisiana) Sediments," Estuarine and Coastal
Marine Science 1 (1973) : 125-135; Louisiana Wildlife and
Fisheries Commission, Cooperative Gulf of Mexico Estuarine
Inventory and Study; and J.F. Mayer, Jr., Modification of
Solvent Extraction Methods and Determination of Trace Metals
in Selected Aquatic Ecosystems in Louisiana (Master's Thesis,
Louisiana State University, 1975).
-269-
-------
The center of Barataria Bay is primarily sandy silt.
Figure A-13 depicts sediment type distribution in the Bara-
taria region. The predominant grain size in Barataria Bay
is coarse and percentage of sand content is high relative to
clay content.
A. 3. 2. 8 Soil Chemistry
The wetlands of Barataria Bay have a higher clay content
(16 to 30 percent) than do the bay and nearshore sediments,
with clay content decreasing from freshwater, to brackish,
to salt marsh. Soil salinity increases along this succession
of marshes. The organic content of soil is higher in the
brackish marsh at 26.7 percent organic carbon and 1.6 percent
organic nitrogen, than it is in fresh or saltwater wetlands.
In the salt marsh soils, organic carbon content ranges from
6 to 9 percent. A high level of sulfide exists in the
brackish marsh and strongly anaerobic conditions are found
beneath the surface layer of soil. Heavy metals which
readily absorb to clay minerals are found at higher levels
in the brackish soils (which have a higher percentage of
clay content) than in the salt marsh soils. Table A-10
and Figure A-14 present data collected along Bayou Lafourche,
which demonstrates these trends.
The soils of the salt marsh are gradually being eroded
by marine waters, thus the salt marsh is in a senescent
state. The boundary between brackish and salt marsh is
gradually migrating inland as the entire coastal zone subsides,
A.3.2.9 Water Chemistry41
The nutrient content of Barataria Bay waters varies
spatially and temporally as a function of salinity, rainfall,
river discharge and related nutrients. Table A-ll presents
1968-1969 nutrient levels for dissolved oxygen, nitrate
(NO3) nitrite (NC>2), inorganic phosphorus and total phosphorus
40
Bahr and Hebrard, Barataria Bay; Biological Charac-
terization; and Louisiana Wildlife and Fisheries Commission,
Cooperative Gulf of Mexico Estuarine Inventory and Study.
41
Ho and Barrett, Distribution of Nutrients in Louisiana
Coastal Waters; and Louisiana Wildlife and Fisheries Commission,
Cooperative Gulf of Mexico Estuarine Inventory and Study.
-270-
-------
90 00-
. \.
*V2P .""^
c; ' IK
0 F
M
90 00-
Figure A-13. Sediment type distribution in the Barataria-
Caminada Bay Area. Base map: U.S. Army Corps of Engineers,
scale 1:250,000. (Louisiana Wildlife and Fisheries Commis-
sion, Cooperative Gulf of Mexico Estuarine Inventory and
Study, Phase III Sedimentology, 1971, p. 155.)
-271-
-------
TABLE A-10
SEDIMENT CONTENT - BARATARIA DRAINAGE BASIN
SAMPLING
STATION
1.
2.
3.
4.
I
^j 5.
to
1 6.
7.
Salt marsh
Salt marsh
Brackish marsh
Brackish marsh
Fresh marsh
Fresh marsh
Fresh marsh
Source: J.F.
of Trace Metals in
SALINITY
(PPt)
19.7
21.8
8.4
6.1
0.62
0.29
0.10
Mayer , Jr
Selected
SEDIMENT
ORGANIC SEDIMENT
CARBON (%) CLAY (%)
7
9
6
26
15
7
7
.5
.0
.5
.6
.0
.5
.1
. , Modification of
Aquatic
Ecosystems
19.7
24.7
30.2
16.8
33.6
24.5
38.1
Fe
(ppm)
494.8
598.9
625.0
562.5
286.4
729.1
833.1
Mn
Cu
(ppm) (ppm)
50.0
27.1
62.5
48.8
30.2
44.8
60.4
Solvent Extraction Methods and
in Louisiana
(Master1
s Thesis,
1.02
2.00
1.21
3.63
5.00
2.35
4.54
Ni
(ppm)
1.64
1.61
1.52
1.50
1.17
1.42
1.79
Pb
(ppm)
0.83
0.67
0.96
0.90
1.31
1.71
1.14
Zn
(ppm)
4.06
3.64
4.48
5.88
3.96
52.03
5.62
Determination
Louisiana
State University, 1975).
-------
BARATARI A
BAY
Figure A-14. Sampling stations for sediment study
(Table 5-10). (Mayer, Modification of Solvent Extraction
Methods and Determination of Trace Metals in Selected Aquatic
Ecosystems in Louisiana (Master's Thesis, Louisiana State
University, 1975).
-273-
-------
TABLE A-11
NUTRIENT LEVELS — BARATARIA BAY WATER COLUMN (1968-1969)
YEARLY
AVERAGE
Dissolved O 8.0
(ppm)
Nitrite 0.45
(mg-at/1)
i
^ Nitrate 4.50
*" (mg-at/1)
Inorganic 0.78
Phosphate
(mg-at/1)
Total 2.93
Phosphorus
(mg-at/1)
Source: Louisiana Wildlife
Mexico Estuarine Inventory and
LOW MONTHLY HIGH
MONTHLY
AVERAGE AVERAGE
6.6 (Aug.) 9.5
0.16 (June) 0.87
0.08 (Oct.) 18.90
0.42 (Nov.) 1.31
1.65 (Jan.) 3.91
and Fisheries Commission
Study, Louisiana, Phase I
(March)
(April)
(March)
(Sept.)
(April)
, Cooperative
I Hydrology,
ABSOLUTE
RANGE
6.0-10.5
0.05-1.98
0.00-56.63
0.25-2.06
0.59-6.68
Gulf of
1971.
-------
Dissolved oxygen levels are directly related to water
temperatures. In summer months, dissolved oxygen reaches a
low, and increases as temperature sinks and wave action (due
to winds and current) increases. In general, dissolved
oxygen levels are higher where salinities are lower, in- the
upper and western portions of the Bay. Average dissolved
oxygen levels in Barataria Bay are close to 8 ppm.
Nitrate levels are highest in periods of high rainfall
and in regions of low salinity. This suggests that input of
large volumes of water draining from the north — which
carry with it nutrients and detritus from fresh and brackish
marshes, will increase nitrate levels in Barataria Bay. The
average nitrate level found in Barataria Bay is 4.5 micro-
moles per liter (ug-at/1).
Nitrite levels correspond closely to nitrate levels.
Highest nitrite levels occur shortly after high nitrate
values are observed indicating that high nitrite concentra-
tions may result from nitrate reduction.
Inorganic phosphate, which averages 0.78 ug-at/1, is
highest in the upper reaches of Barataria Bay and like
nitrite and nitrate, may be related to freshwater drainage
from wetlands to the north. Similarly, total phosphorus is
higher during periods of peak river discharge and corres-
ponding low salinities, and is higher in the upper estuary
than it is near the Gulf of Mexico. An average value for
total phosphorus is 2.9 ug-at/1 of which approximatley 26
or 27 percent is organic.
-275-
-------
42
A.3.2.10 Wetlands Biology
The wetlands of the Barataria drainage basin have been
divided into three subunits: freshwater swamps and marshes,
brackish marshes, and salt marshes. Each of these subunits
has a characteristic salinity range, vegetative assemblage,
and productivity. Approximately 66 percent of the Barataria
wetlands is a freshwater environment (0 to 5 ppt); 20 percent
is brackish marsh (6 to 13 ppt) and 14 percent is salt marsh
(14 to 30 ppt). Figure A-9 depicts the distribution of wet-
lands near Barataria Bay. For the purposes of this study,
we will deal only with the brackish and salt marshes, two
systems which have interdependent hydrology, nutrient cycles,
and energy flow.
A.3.2.11 Brackish Marsh
The brackish marsh represents an intermediate zone
between the freshwater and marine ends of the Barataria
Drainage Basin. This area forms a band stretching across
the drainage basin from below the Intracoastal Waterway to
the salt marsh, lakes, and estuaries fringing Barataria Bay.
42
Bahr and Hebrard, Barataria Basin; Biological Charac-
terization; Barrett, Barney, Gillespie, and Cannon, Primary
Factors Which Influence Commercial Shrimp Production in
Coastal Louisiana, Technical Bulletin No. 9 (New Orleans:
Louisiana Wildlife and Fisheries Commission, Oysters, Water
Bottoms and Seafood Division, 1973); J.W. Day, Jr., W.G. Smith,
P.R. Wagner, W.C. Stowe, Community Structure and Carbon
Budget of a Salt Marshand Shallow Bay Estuarine System in
Louisiana (Baton Rouge: Louisiana State University, Center
for Wetland Resources, May 1973); Galdry, J. Wilson, and
C.J. White, Investigations of Commercially Important Penaeid
Shrimp in Louisiana Estuaries, Technical Bulletin No. 8
(New Orleans: Louisiana Wildlife and Fisheries Commission,
Oysters/ Water Bottoms and Seafood Division, March 1973);
Eugene Jaworski, The Blue Crab Fishery, Barataria Estuary,
Louisiana (Baton Rouge: Louisiana State University, Center
for Wetland Resources, 1972); Louisiana Wildlife and Fisheries
Commission, Cooperative Gulf of Mexico Estuarine Inventory
and Study; and J. Thomas, P. Wagner, and H. Loesch, "Studies
on the Fishes of Barataria Bay, an Estuarine Community,"
Coastal Studies Bulletin No. 6 (Baton Rouge: Louisiana State
University, Center for Wetland Resources, 1971).
-276-
-------
At the basin's center the band of brackish marsh is 15 miles
wide, tapering as it approaches the Mississippi River and
Bayou Lafourche on either side. The major waterbodies of
the brackish marsh are Little Lake, Turtle Bay and Bayou
Perot.
The dominant plant species in the brackish marsh are
Spartina patens (wire grass) which comprises 45.8 percent of
the marsh vegetation, and Distichlis spicata (salt grass)
which contributes 29 percent. Spartina alterniflora (oyster
grass, Juneus romerianus (black rush) and Scirpus olneyi
(three-cornered grass) are also important primary producers.
Table A-12 lists key species of primary producers found in
brackish and salt marsh environments. Total annual net
primary production in the brackish marsh is estimated at
1 kg/m2, though this is somewhat speculative.43 The brackish
marsh does have the greatest live biomass of any marsh type,
attributed to the dense stands of wire grass and salt grass
which make up 75 percent of the vegetative cover.
All the marsh trophic systems are detritus-based,
meaning that energy trapped in primary production is utilized
as dead plant material by community heterotrophs. Herbivores
play a relatively minor role in utilization of primary
productivity. Insects and marsh snails graze approximately
7 percent of live plant material and muskrats account for
another 2 percent. The low level of grazing is responsible
for the net buildup of detritus (as peat) which occurs in
the brackish marsh. The detritus is consumed by a variety
of detrivores including numerous amphipods, nematodes, and
microbes. These are, in turn, consumed by higher inverte-
brates, oysters, shrimp and crabs, which are preyed on by a
variety of marsh birds and mammals.
The trophic systems of the waterbodies associated with
the brackish marsh are similarly detritus-based. Rapid
chemical changes are, characteristic of these areas and
organisms which reside in these estuaries tolerate changes
in salinity and water chemistry through various physiological
mechanisms. Aquatic macrophytes such as widgeon grass, and
dwarf spikerush, phytoplankton, and shallow water benthic
diatoms, are the primary producers in these waterbodies.
Ducks and other waterfowl graze on some of the macrophytes
but the dominant energy flow pathway is through detri-
tivorous polychaetes, nematodes, amphipids, ostracods, blue
43
Bahr and Hebrard, Barataria Basin; Biological Charac-
terization.
-277-
-------
TABLE A-12
PRIMARY PRODUCERS - BARATARIA BAY
BRACKISH AND SALT MARSHES AND ASSOCIATED WATERBODIES
c»
I
MACROPHYTES
EPIPHYTES
FILAMENTOUS DIATOMS
BENTHIC
PHYTOPLANKTON
Spartina
alterniflora
Juncus
romerianus
Distichlis
spicata
Spartina
patens
Eleocharis
parvula
Scirpus
olneyi
Enteromorpha
Ectocarpus
Cladophora
Polysiphonia
Rhizoc Ionium
Bostrychia
Erythrotrichia
Spirulina
Oscillatoria
Lyngbya
Denticula
Amphiprora
Amphora
Nitzschia
Melosira
Rhopalodia
Diploneis
Cymbella
Cy 1 indrothe ca
Grammatophora
Surirella
Achnanthes
Cocconeis
Pleurosigma
Navicula
Camphylodiscus^
Achnanthes
Amphiprora
Amphora
Anaulua
Caloneis
Cocconeis
Cosmiodiscus
Diploneis
Eunotogramma
Gyros igma
Mastogloia
Melosira
Navicula
Nitzschia
Plagiogramma
Pleurosigma
Rhaphoneis
Stauroneis
Surirella
Trachysphenia
Coelosphaerium
Gomphosphaeria
Merismopedia
Microcystis
Anabaena
Spirulina
Oscillatoria
Actinoptychus
Biddulphia
Chaetoceros
Coscinodiscus
Melosira
Amphiprora
Camphylodiscus
Navicula
Nitzschia
Ankistrodesmus
Gymnodinium
Eugena gracilis
Coccoid greens
-------
crabs, and other crustaceans. Acartia tonsa, the dominant
copepod, is both herbivorous and detrivorous. Estuarine
finfish, such as the spot, flounder, croaker, sea trout,
black drum and red drum feed on these detritivores. Wading
birds and mammals such as raccoon and otters are often the
top carnivores in the brackish marsh food chains. Table A-13
lists the key consumers of the brackish marsh, salt marsh,
and associated waterbodies, their importance, and trophic
characteristics.
A.3.2.12 Salt Marsh
Salt marshes are normally more subject to modification
by physical processes than other types of wetlands. The
salt marshes of Barataria Bay (and the whole Louisiana
coast) are closely associated with the physical regime of
the Gulf of Mexico. The diurnal and seasonal variations in
water level produced by tidal inundation, storm surges and
freshwater floods, are important to the species which spend
one part, or all of their life cycle in the marshes, and to
the nutrient cycling and waste removal processes so essential
to high marsh productivity.
A conservative estimate of annual salt marsh production
is 1 kg/m2; however, published estimates have exceeded
3 kg/m2.44 it is generally agreed that salt marshes are the
most productive wetlands and have the lowest species div-
ersity. Spartina alterniflora (oyster grass) is the domi-
nant producer, comprising 63 percent of the vegetative
cover. Distichlis spicata (salt grass) and Juneus romerianus
(black rush) comprise another 25 percent. Benthic diatoms
and epiphytes on Spartina stems contribute significantly to
primary productivity during winter and early spring, before
Spartina becomes dense.
Several functional advantages are obtained from a
Spartina-based community. The extensive root system provides
erosion resistance to the surface sediments, a feature
especially valuable in strong storms or hurricanes. The
roots also act as a nutrient pump by extracting phosphorus
from aerobic sediments and transporting it to upper portions
of the plant where it can be released to surrounding waters
during tidal inundation.
First order consumers of the salt marsh (herbivores and
detritivores) include bacteria, fungi, copepods, amphipods,
44
Bahr and Hebrard, Barataria Basin; Biological Charac-
acterization.
-279-
-------
TABLE A-13
KEY CONSUMERS - BARATARIA BAY
BRACKISH AND SALT MARSHES AND ASSOCIATED WATERBODIES
INVERTEBRATES
FISH
BIRDS
MAMMALS
COMMERICAL
AND SPORT
SPECIES
Callinecte3 sagidis
(Blue Crab)
(Brown Shrir?p)
' Pgrcaeus setifgrus
(White Shirmp)
' j'^paeus duprarum
{Pink Shrimp)
(Oyster)
> -^f -ft Brevoojrtia, patron us
(Menhadden)
ft Apcftoa natchjj.li
(Bay Anchovy)
t ^r iV Micropogon u-idulatus
{Atlantic Croaker)
•fr Arius felis
\Sea Caccish)
ft LgAOS tomus xanthurus
(Spot)
Chlo ros combrus chrysurus
(Bumper)
ft Cynpscion arenarius
(Sand Sea Trout)
ft Cynoscion nebulosus
(Spotted Sea Trout)
• •& Mugil cephalus
(Striped Mullet)
ft Pa r a 1 i c ht h y s lethos t^igir^a
(Southern Flounder)
ft Pggonias cromis
(Elack Drum)
•^ Sci^anops ocellata
Procyon lotor
{Racoon)
(Otter)
• Odatra zibethicus
(Muskrat)
Detriti\*ore
ft Men
^
(Tidewater Silverside)
THOPRICAuLY
IMPORTANT
SPECIES
• Acartia tonsa
(Copepod)
(Marsh Snail)
• jr Rancea cuncatus
•ff Pelecanus erythrorhyncon
(White Pelican)
it Dichromanassa rufescens
(Reddish Egret)
tV Circus cyaneus
ilrTursioos truncatus
(Bottlenoae Dolpmn)
(Clan)
(Marsh
(Gull)
ft Florida caerulea
^Little Blue Hc-on)
ENDA.NGEREO
SPECIES
•fr Pelqcamis oj^cLc*nr.t^al_ig
(b roivTi Pf 1 lean)
-280-
-------
snails, fiddler crabs, polychaetes, mussels, insects, birds
and mammals. Grasshoppers and similar insects are the only
true grazers. Insects are thought to remove about 4 percent
of net primary production. Microfauna and small macrobenthos
are important consumers in salt marsh sediments, ingesting
approximately half the weight that macrofaunal forms do.
The total biomass of primary consumers is estimated to be 16
g/m2 at the ocean edge of the estuary, 40 g/m2 10 feet
inland, and declining further inland to 5 g/m2.45
Salt marsh predators include a variety of wading birds,
mammals, insects and spiders.
The waterbodies associated with salt marshes are the
bays which interface with the Gulf of Mexico, Barataria and
Caminada Bays, and attached lakes. The salt waterbodies are
about half as productive as the salt marshes themselves, but
the primary production of diatoms, coccoid blue-green
algae, green algae and nannoplankton, may be utilized more
directly than marsh grass. These waterbodies have the
greatest primary productivity relative to consumption of all
waterbodies in Barataria Basin.
Major herbivores of these systems include Acartia tonsa
(the dominant copepod), menhaden and mullet. Detrivores are
quite numerous including commercially important species of
penaeid shrimp, blue crabs, and oysters. Important carni-
vores include ctinophores (which feed on zooplankton),
fishing birds, diving ducks, spotted sea trout, sea catfish,
silversides, anchovy and the bottlenosed dolphin (see
Table A-13).
Many of the faunal species of Barataria Bay mentioned
above have rather complex life-history and migration patterns,
spending different parts of their cycles in different habi-
tats. There are four basic patterns or categories into
which these species fall: (1) truly estuarine species,
which spend their entire lives in the bay; (2) marine
species which spawn in the sea and use the estuary as a
nursery ground; (3) marine forms which visit the estuary as
adults; and (4) freshwater fish which occasionally enter the
brackish waters of Barataria Bay.
Those species which spend all or almost all of their
life in the brackish and saline waters of Barataria Bay and
associated lakes include the eastern oyster, the bay anchovy,
45
Day, Smith, Wagner, and Stowe, Community Structure
and Carbon Budget, 1973.
-281-
-------
the Atlantic needlefish, the tidewater silverside, the
hogchoker and various killifish. Many benthic species of
nematodes, polychaetes, bivalves, and amphipids also spawn,
hatch, mature and die in estuarine waters.
Some of the most commercially important species fall
into the second pattern, living in both open Gulf waters and
enclosed bay waters. The blue crab, which supports a large
fishery, spawns in lower estuarine and Gulf waters. The
larval stages, zoea (31 to 49 days) and megalops (6 to
20 days) are spent in open Gulf waters. Near the end of the
megalops stage the blue crabs may enter tidal inlets, and
the first nine months of the juvenile stage are spent in the
upper and lower estuary. The second year as a juvenile is
spent in the upper estuary where the crab grows to full
maturity and mates. It is at this time that crabs are
fished — usually from ages 12 to 18 months. Those crabs
not caught return to open ocean waters to spawn.46
The penaeid shrimp, white, pink and brown shrimp,
follow a similar pattern. They spawn in offshore Gulf
waters at depths of 5 to 17 fathoms. After hatching the
nauplii lead a planktonic existence for 3 to 5 weeks, then
metamorphose into a postlarval stage and enter the estuary.
Five or six months after hatching the shrimp are mature and
migrate into the open ocean to spawn.47
Fish species which spawn in the Gulf (usually in
spring) and use the Barataria Bay as nursery grounds include
the large-scale menhadden, Atlantic croaker, spotted and
sand sea trout, silver perch, striped mullet, spot, and bay
whiff.48 Most of these species remain in the estuary until
late summer and return to the open ocean as subadults in the
fall. However, the sand sea trout and the mullet move
inshore in the fall, spending warmer months in the Gulf.
Some fish spawn and live primarily in offshore waters
but seasonally visit the estuary in late summer and early
Jaworski, Blue Crab Fishery.
47
Barrett, Barney, Gillespie, and Cannon, Primary
Factors which Influence Commercial Shrimp Production; and
Galdry, Wilson, and White, Investigation of Commercially
Important Penaeid Shrimp.
48
Thomas, Wagner, and Loesch, "Studies on Fishes of
Barataria Bay."
-282-
-------
fall. The jacks, sea catfish, moonfish, and lizard fish
follow sxxch a pattern.
Occasionally freshwater fish will move downstream and
enter the brackish waters of the Barataria system. The
spotted gar is one such species.
Table A-14 lists, by migratory patterns, various
species of fish and invertebrates commonly found in Barataria
Bay.
A.3.3 Gulf Of Mexico Waters
49
A.3.3.1 Temperature
Surface and bottom temperatures vary seasonally. There
is little difference in temperatures of surface and bottom
waters in the fall and early winter. During the cooler
months, December to April, surface temperatures become lower
than bottom temperatures, and in spring and summer they
become warmer than bottom temperatures.
Surface temperatures average 26° C, rising to over 30° C
in summer and sinking to 16° C in winter. Bottom tempera-
tures average 22° C to 23° C, rising just slightly in summer
and sinking to 19° C in winter. Surface temperature varies
little with distance from shore; however, in summer near
offshore bottom temperatures are one or two degrees higher
than those far offshore, and the trend is reversed in winter.
A.3.3.2 Depth50
The near affshore region of the continental shelf
slopes seaward at 15 ft/mi (2.5 m/km). The average depth
49
Barrett, Barney, Gillespie, and Cannon, Primary
Factors which Influence Commercial Shrimp Production; and
Gosselink, Miller, Hood, and Bahr, Louisiana Offshore Oil
Port.
P. Detking, R. Buck, R. Watson, and C. Merks, "Surface
and Shallow Subsurface Sediments of the Nearshore Continental
Shelf of South Central Louisiana," in Offshore Ecology Study
(Galveston, Texas: Gulf Universities Research Consortium,
October 1974) .
-283-
-------
TABLE A-14
MIGRATORY PATTERNS OF BARATARIA BAY SPECIES
ENTIRE LIFE SPENT
IN THE ESTUARY
SPAWN IN OFFSHORE //ATERS
MATURE IN ESTUARY
ENTER ESTUARY SEASONALLY
AS AN ADULT
FRESHWATER SPECIES
OCCASIONALLY ENTERING
BRACKISH WATERS
I
K)
00
Anchoa mllchilli - bay anchovy
Strongylura marina - Atlantic needlefish
Hen1Jla berylllna - tidewater silverside
Trinectes rcaculatus - hogchocker
Cyprlnodon varleg.itus - sheepshead
minnow
Crassostrea virglnica - eastern oyster
Bi-evoortla patronus - mcnl
-------
3 miles offshore is approximately 30 feet. Beyond this
point, the grade lessens to a slope of 4 ft/mi to 6 ft/mi
(0.7 m/km to 1 m/km).
A. 3. 3. 3 Tides And Currents51
Tides in this area are dominantly diurnal, and exert
their maximum influence on shelf currents in December and
June when the sun reaches its maximum declination. The
minimum influence is felt in March and September when the
sun is over the equator. Any effects of tides on currents
are superimposed on the net drift of regional currents.
Movement of the water column offshore Barataria Bay is
driven primarily by local and regional winds, passage of
diurnal tides, and impingement of regional Gulf of Mexico
currents onto the continental shelf. Figure A-15 depicts
general circulation patterns in the Gulf of Mexico. The
site area for this study is located on the northeast corner
of a counter clockwise circulation current in the northwest
Gulf of Mexico. This circulation is modified by those
factors mentioned above.
The annual net movement of waters offshore of Barataria
Bay is westerly. However, net water movement is easterly in
summer with surface currents averaging 0.40 knots, onshore
(towards shore) offshore (away from shore) mid-depth cur-
rents averaging 0.26 knots, and onshore bottom currents
averaging 0.22 knots. In winter and early spring net water
movement is westerly, with surface currents averaging
0.82 knots. Mid-depth currents are offshore and bottom
currents occur onshore and offshore. In general, current
speed tends to decrease with depth. Figure A-16 depicts
seasonal variations in current movement in the northwestern
Gulf waters.
A. 3. 3.4 Salinity52
In general, salinities on the Louisiana continental
shelf increase with increasing distance from shore, and with
Detking, Buck, Watson, and Merks, "Currents on Nearshore
Continental Shelf."
52
P. Detking, R. Buck, R. Watson, and C. Merks, "-Hydrog-
raphy on the Nearshore Continental Shelf of South Central
Louisiana," in Offshore Ecology Investigation (Galveston,
Texas: Gulf Universities Research Consortium, May 1974).
-285-
-------
Figure A-15. General circuation patterns in the
Gulf of Mexico. (U.S. Naval Oceanographic Office,
Oceanographic Atlas of the North Atlantic Ocean,
No. 700, Sect. 1, Tides and Currents.)
-286-
-------
30-
Z8-
26-
96
-------
greater depths. Freshwater discharge from local runoff and
the Mississippi River acts to lower salinity in surface
waters and waters closer to shore. Mean surface salinities
range from 19 to 21 ppt, while mean bottom salinities vary
from 31 to 33 ppt. During the second .half of the year
surface salinities are only slightly lower than bottom
salinities and no steep vertical salinity gradients occur.
This lack of stratification is due to thorough mixing of
water by winds and currents in fall and early winter. In
mid-winter the lessening of freshwater runoff and the bottom
currents are responsible for a rise in bottom salinities to
35 or 36 ppt, the normal salinity of open ocean. In late
winter, spring, and early summer pronounced vertical salinity
gradients are observed, beginning at depths of 10 feet. In
spring surface salinities often fall below 15 ppt, a result
of heavy input from local runoff and the flooding Mississippi
River. During this period there is little exchange between
surface and bottom waters.
Surface and bottom salinities usually increase in an
offshore direction. Mean surface salinities in near off-
shore waters do not vary significantly from surface salini-
ties far offshore; they are approximately 19 ppt. However,
mean near offshore bottom salinities average 25.6 ppt, a
value notably lower than far offshore bottom salinities. At
certain times of the year offshore waters are highly diluted
and salinity increases in a shoreward direction. This
occurs when the Mississippi River is in a flood stage and
near offshore surface currents flow to the west, or when
strong north winds push brackish waters out of the bays.
A. 3 . 3 .5 Turbidity53
Turbidity of offshore Gulf waters is strongly influ-
enced by the magnitude and turbidity of Mississippi River
discharge, by local freshwater discharge, and by current
patterns carrying this flow. Turbidity is greatest in
shallow waters and areas closest to shore. Near offshore
stations exhibit visibility ranging from 1.5 to 21 feet
G.M. Griffin and B.J. Ripy, "Turbidity, Suspended
Sediment Concentrations, Clay Mineralogy of Suspended Sedi-
ments and the Origin of the Turbid Near-Bottom Water Layer,
Louisiana Shelf South of Timbalier Bay," in Offshore Ecology
Investigation (Galveston, Texas: Gulf Universities Research
Consortium, May 1974).
-288-
-------
with far offshore visibility ranging from 3.5 to 50 feet.
Surface turbidity is highest in May, June, and February, and
lowest in September and March.
During most of the year a very turbid layer of water is
found near the shelf floor, though it varies seasonally in
thickness and concentration. The sediments of this turbid
bottom layer have a clay mineral composition identical to
the suspended sediments of the Mississippi River. During
spring flooding the suspended sediment of the entire water
column bears this same composition. The turbid bottom layer
is associated with low dissolved oxygen concentrations which
drop further in summer.
54
A.3.3.6 Sediment Chemistry
Offshore sediments originate from the Mississippi
River, estuarine marshlands and settling silaceous and
calcareous organisms living in Gulf waters. The sediments
contain high levels of organic materials, associated heavy
metals, and nutrients.
Nutrient concentrations in sediments seem to be five to
eight times as high as the adjacent water column. They also
seem to decrease further offshore. Nitrogen (nitrite plus
nitrate) averages 0.5 to 0.6 ppm and total phosphorus
averages 2.2 to 2.3 ppm. Hydrocarbon content in sediment
ranges from 3.4 to 19.7 ppm. Biological Oxygen Demand
ranges from 100 to 740 mg/kg (40 percent of total OD) and
decreases with distance offshore. COD ranges from 14,700 to
21,000 mg/kg and decreases with increased water depth.
Heavy metal values are summarized in Table A-15. No distinct
trends are observable in metal content relative to depth,
season or distance offshore.
A.3.3.7 Water Chemistry
Oxygen, nutrients, and metals are key parameters in
determining the chemical nature of a water body, and the
54
Gosselink, Miller, Hood, and Bahr, Louisiana Offshore
Oil Port, Appendix V.
Gosselink, Miller, Hood, and Bahr, Louisiana Offshore
Oil Port, Appendix V; and Ho and Barrett, Distribution of
Nutrients in Louisiana Coastal Waters.
-289-
-------
TABLE A-15
GULF WATERS - HYDROCARBON AND METAL CONTENT
SEDIMENTS
(ppm)
WATER
(ppb)
HYDROCARBONS
HEAVY METALS
3.4 - 19.7
18 - 64
Cd ND -
Cr ND -
Cu 1.2 -
Fe 1430 -
Pb 5.1 -
Mn 17.5 -
Hg (ppb) 0.0061 -
Ni 2.3 -
Zn 10.1 -
V 28 -
1.5
39.6
8.7
5100
92.8
247
0.0417
57.9
39.9
79
ND -
ND -
ND -
ND -
ND -
ND -
ND -
ND -
ND -
ND -
ND -
ND -
0.22 -
0.22 -
ND -
ND -
ND -
ND -
3.1 (surface)
2.8 (bottom)
55.3
29.0
5.7
15.1
18.2
14.2
36.7
26.7
6.8
7.6
1.36
1.14
5.2
22.1
17.0
32.8
ND = not detectable.
Source: J.G. Gosselink, R.R. Miller, M. Hood, and
L.M. Bahr, Jr., Louisiana Offshore Oil Port: Environmental
Baseline Study, Appendix V (Baton Rouge: Louisiana State
University, Center for Wetland Resources, 1975).
-290-
-------
type of life it can support. Often the levels of these
constituents vary spatially with depth or distance from
shore, or temporally with season.
Surface and bottom concentrations of dissolved oxygen
reflect seasonal trends in temperature, mixing, salinity,
respiration, decomposition and photosynthesis. High DO
levels are found in conditions of low temperature, high wave
turbulence, low salinity and high photosynthetic rates.
Surface dissolved oxygen ranges from 6 ppm in summer to
10 ppm in winter. While cold water and winter storms
increase the probability that surface waters will become
supersaturated with oxygen, uptake by organisms will have
little effect on surface DO levels because oxygen can be
easily replenished at the air/sea interface.
Bottom dissolved oxygen has greater seasonal variations,
ranging from 1.1 ppm in summer to 7.5 ppm in winter, with an
annual average of 2 ppm in far offshore waters. Near off-
shore waters have somewhat higher levels with an annual mean
of 3.4 ppm. A large portion of the bottom waters both near
and far offshore are anoxic (0 to 2 ppm DO) during the
warmer months of the year. This is thought to be associated
with a turbid bottom layer and high BOD.
Nitrogen, measured as nitrate plus nitrite, averages
0.14 ppm in offshore waters. Nitrogen content remains
constant with depths but has higher values in summer months
and in areas further offshore.
Total phosphorus averages 0.33 ppm with levels slightly
higher in surface waters. Means of surface, mid-depth and
bottom waters average 0.35, 0.31 and 0.30 ppm, respectively.
Highest surface and mid-depth values are found in winter
months. Phosphorus levels seem to be a function of salinity
and Mississippi River discharge.
Mean organic carbon content of near offshore waters is
5 mg/1, while more open Gulf waters average 1.5 to 2.0 mg/1.
High organic content of offshore waters may be contributed
by the Mississippi River plume, detritus exported from the
southern Louisiana salt marshes, and the oil industry.
Heavy metal concentrations are presented in Table A-15.
All levels are normal for coastal water with the exception
of mercury which is unusually high.
-291-
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A.3.3.8 Gulf Biology56
The Gulf of Mexico waters adjacent to Barataria Bay
yield extremely high catches of commercially important fish
and shellfish. This high faunal productivity is attributable
to elevated nutrient levels, resulting from export of
primary production from adjacent wetlands to the Gulf via
waterways draining the coastal system, and from organic
matter carried in the Mississippi plume. It has also been
suggested that the productiveness of these fisheries par-
tially results from entrapment of offshore marine animals,
which are prevented from eastward migration by the fresh-
water Mississippi discharge and by the extension of the
modern delta (which narrows the adjacent shelf area).
Primary production in offshore waters is almost en-
tirely planktonic. Diatoms, dinoflagellates and nanno and
ultra-plankton are the dominant phytoplankton forms.
Macrophytes are found only on man-made structures such as
oil platforms. Table A-16 lists major primary producers in
offshore waters. Planktonic productivity (both phyto- and
zooplankton) is greatest in near offshore waters and de-
creases further offshore along a gradient of decreasing
organic content in the water column.
Herbivores play a more significant trophic role in
offshore energy transport than they do in the wetlands.
Acartia tonsa and Paracalanus sp. feed on huge amounts of
phytoplankton and particulate detritus, forming a major link
between primary production and higher trophic levels in the
offshore ecosystem. Despite the high level of grazing,
detritivores still form a key part of the offshore community.
The benthic macrofauna, which are an important food source
for bottom feeding nekton such as flounders, silversides,
spot, and croakers, are dependent on a continual rain of
detritus from the euphotic zone above. These benthic filter
and deposit feeders include clams, polychaetes, sand dollars,
sea cucumbers, brittle stars, bryozoans, sponges, barnacles
and mussels. Mud crabs, mud snails and amphipods are motile
forms which scrape detritus from the surface of the ocean
56
Fred Dunham, A Study of Important Estuarine Dependent
Fishes, Technical Bulletin No. 4 (New Orleans: Louisiana
Wildlife and Fisheries Commission, Oyster, Water Bottoms
and Seafood Division, 1972); and Gosselink, Miller, Hood,
and Bahr, Louisiana Offshore Oil Port.
-292-
-------
TABLE A-16
PRIMARY PRODUCERS - GULF WATERS
NEAR AND FAR OFFSHORE
DIATOMS
DINOFLAGELLATES
Asterinella
Biddulphia
Coscinodiscus
Cyclotella
Lithodesmium
Navicula
Pleurosigma
Surirella
Stauroneis
Thallasiosira
Fragilaria
Rhizosolenia
Ceratium
Exuviaella
Gonyaulaux
Gymnodinium
Peridinium
-293-
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floor. Smaller meiofauna such as nematodes, cilliate proto-
zoa, and microbes are also important detrivores. Detriti-
vorous finfish include menhaden, mullet, anchovy, croakers,
silversides and threadfins. These fish feed indiscriminately
on detritus in offshore waters as adults; however, they seem
to be much more selective, searching out specific zooplankton
forms, during the larval and juvenile stages of their life
cycle.
Many of the offshore predators are the same predators
found in the salt marsh estuaries. In fact most of these
species are hatched offshore and migrate into the estuary
during their greatest growth periods, to take advantage of
the abundant food supply present. Offshore predators
include spotted sea trout, red and black drum, red snapper,
flounder, and blue marlin. Invertebrates such as shrimp,
starfish and boring snails prey on benthic organisms.
Predatory birds feeding offshore include the laughing gull,
ring billed gull, herring gull, frigate birds and brown
pelicans. The only mammal found in this offshore environ-
ment is the bottlenosed dolphin. Table A-17 presents the
key consumer species in the ecosystem offshore of Barataria
Bay. These species were selected for their commercial
importance, abundant numbers, or endangered-species status.
-294-
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TABLE A-17
KEY CONSUMERS - NEAR AND FAR OFFSHORE GULF WATERS
(ADJACENT TO BARATARIA BAY, LOUISIANA)
INVERTEBRATE
FISH
BIRD
MAMMALS
COMMERCIAL
SPECIES
* Penaeus aztecus
(Brown Shrimp)
ir Penaeus setiferus
(White Shrimp)
* Penaeus durorarn.il
(Pink Shrimp)
rif Callinectes sapidis
(Blue Crab)
if if Anchoa mxtchilli
(Bay Anchovy)
if Cynoscion arenanus
(Sand Sea Trout)
ir Peprilus burti
(Gulf Butterfish)
Etropus crassostus
(Fringed Flounder)
SPORT SPECIES
if Centropistes philadelphica
(Rock Sea Bass)
if Tnchiurus lepturus
(Cutlass Fish]
if Leiostorous xanthurus
(Spot)
if it Arius felis
(Sea Catfish)
ir ir Micropogon undulatos
(Atlantic Croaker)
ifChloroscombrus chrysurus
(Atlantic Bumper)
TROPHICALLY
IMPORTANT
SPECIES
• *
Gamma rus sp.
(Amphipod)
Acartxa tonsa
(Copepod)
• ir Paracalanus sp.
(Copepod)
ir Xiphopenaeus sp.
(Sea Bob)
ir Sguilla sp.
(Mantis Shrimp)
• •* Mulina SB.
(Pelacypod)
irir Cibanarius vittatus
(Hermit Crab)
Loliguncula brevis
(Squid)
Prionotus roseus
(Blue Spotted Sea Robin)
•ft Sterna sp.
(Tern)
•{f Aytha affinis
(Lesser Scaup)
•fr Larus atricillia
(Laughing Gull)
if Fregata magnif icens
(Frigate Bird)
if Larus Philadelphia
(Bonaparte's gull)
if Tursiops truncatus
(Bottlenose Dolphin)
ENDANGERED
SPECIES
Pelecanus occientalis
(Brown Pelicaji)
* Detritivore
ir Carnivore
• Herbivore
-295-
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APPENDIX B
DESCRIPTION OF DISPERSION MODELS
B. 1 Introduction
Oilfield brines, once discharged into the receiving
waterbody, are subjected to the processes of dilution,
transport, and diffusion which play a very important role in
determining the distribution of pollutant concentrations.
Since the impact exerted on the marine environment by the
brine discharge depends in large part on the concentration
distributions of the discharged contaminants in the receiv-
ing waters, it is of great importance to understand and
predict the physical dispersion processes which determine
these distribution patterns. The purpose of this appendix
is to discuss the principles of dispersion modeling and the
models used in this study to estimate the dispersion of the
discharged brine. The simplest type of calculation, the
tidal prism flushing model, is discussed in Section B.2.
This model is useful for giving the average concentration of
a pollutant in a small bay area but cannot give any infor-
mation regarding concentration contours. Section B.3
treats the basic ideas and principles involved in modeling
eddy diffusion. These principles are then applied in
Section B.4 to an analysis of the problem of the dispersion
of a pollutant in a steady uniform current in one direction.
The final section discusses the computerized diffusion model
used in this study to predict concentration contours. This
model is capable of incorporating three-dimensional diffu-
sion as well as time varying tidal currents which play a key
role in estuarine dispersion.
B.2 Simple Tidal Flushing Calculations for Shallow,
Enclosed Bays
Pollutants introduced into an estuary are flushed out
over a period of time by the combined actions of seaward
river flow and mixing at high tides followed by tidal
outflow. The residence time of estuarine pollutants is
highly dependent on the overall rate at which this flushing
occurs. Therefore, one important indicator of the ability
of an estuary to rid itself of pollutant discharges —
especially if they are conservative — is the flushing time,
or the length of time required for the river flow and tides
to flush an amount of water equal to the low tide volume of
-297-
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the estuary. For very large estuaries or those which have
complicated geometries the flushing time is quite difficult
to compute; however, for small estuaries or rough calcula-
tions, a relatively simple method has been developed to make
reasonable estimates of the length of time, measured in
units of tidal periods, needed to replace the estuary
volume.
Such calculations are useful for two reasons. First,
they can be used to gain a rough idea of the length of time
it takes an estuary to rid itself of oilfield brine pollu-
tants dissolved in the water column. Second, in the case of
continuous discharges, they can be used to determine the
steady state concentrations of those pollutants. This
second reason is an important one, for the computer model
described in Section B.5, used to determine concentration
profiles around the discharge points, is not capable of
accounting for more than one straight-line boundary of an
estuary. The rougher, less sophisticated calculations
described below in this section can be used to supplement
the predictions of the computer model in small, enclosed
bays by supplying order-of-magnitude estimates of the
average background levels of discharged pollutants. These
estimates are not only useful in their own right but can
also serve as checks on the reasonableness of the results
obtained from the computer model.
The simplest version of the method to be discussed is
based on the fairly crude assumption that the total volume
of water entering the estuary between low and high tides
(incoming river water plus incoming seawater) becomes
thoroughly mixed with the low tide volume before the ebb
tide begins. On the basis of this assumption, the fraction
of the low tide estuary volume ("old water") flowing seaward
during the ebb tide can be computed. In particular, if V is
the low tide volume of the estuary and P is the volume
entering between low and high tides (called the tidal
prism), then V + P is the volume of the estuary at high
tide. Since the tidal prism P is carried away on the next
ebb flow and since the total high tide volume is assumed to
be thoroughly mixed, the fraction of the volume V of old
water carried away per tidal period is P/(V + P). The
number T of tidal periods needed to flush out all of the old
water is just the inverse of this fraction:
-298-
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This number is a first estimate of the flushing time.
As ought to be expected, this simple-minded method
generally yields shorter-than-realistic flushing times for
most types of estuaries.2 For most real estuaries, complete
mixing during high tide does not occur, and the ebb tide
does not always carry waters near the head of the estuary
all the way past the mouth and into the open sea.
Despite this drawback, the approach leads to an equa-
tion relating the low-tide, steady-state concentration of a
given contaminant to the amount of pollutant discharged into
an estuary. For simplicity we will assume that all of the
discharge occurs between low tide and the following high
tide. Let the concentration of the contaminant at low tide
(ambient concentration) be CL and its concentration in the
discharge stream be CD in a total volume VD of discharge in
one tidal cycle. Then the quantity of contaminant present
at low tide is VC^, and the quantity present at high tide is
VCL + VDCD. From the discussion above, the quantity of
contaminant removed during each ebb tide is
Q =
V + P
(VC
VDCD)
Since the concentration is assumed to be at a steady state,
Q_ must equal the amount of contaminant Q+ = V^C^ added per
tidal cycle. Hence
(VC
= VD
Solving for C-, the steady-state low tide concentration,
gives
(B-l)
Hackberry Bay, 29°14', 90°15' (see Figure B-l) in the
northwest corner of Barataria Bay, Louisiana, provides a
F.F. Wright, Estuarine Oceanography, Council Education
in the Geological Sciences Publication No. 18 (New York:
McGraw-Hill Inc., 1974), pp. 28-33; and K.R. Dyer, Estuaries;
A Physical Introduction (London: John Wiley and Sons, 1973),
pp. 109-114.
2
Dyer, Estuaries: A Physical Introduction, pp. 109-114.
-299-
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HACKSERRY BAY
FRESH MARSH
(0-5 ppt.)
SALT MARSH
(14-30 ppt.)
Figure B-l. Location of Hackberry Bay study area.
-300-
-------
good example of the kind of bay for which this approach can
be useful. It harbors Texaco1s Bay de Chene oilfield, the
site of the largest brine discharge (Vp = 9,747 m3 per tidal
period) in Barataria Bay. The average tide height in Bara-
taria Bay3 is 0.3 m; if we assume this datum for Hackberry
Bay our estimate of CL is likely to be slightly low, since
the smaller bay probably experiences less extreme tides than
the larger one. This tide height multiplied by the surface,
area of Hackberry Bay of 1.77 x lO^m2 gives P = 5.33 x 106m ;
if the tide height is 0.1 m, P = 1.78 x 106. By (B-l),
assuming 0.3 m tides gives
CL = 1.8 x 10~3 CD
assuming 0.1 m tides gives
CT = 5.5 x 10~3 Cn
Li LJ
Table B-l shows the computed dilution factors for Hackberry
Bay and two other enclosed discharge sites (the Lake
Washington field operated by Texaco and Exxon and Getty's
Manila Village field in Mud Lake.
It is important to emphasize that these results have
considerable limitations. To begin with, the methodology is
based on the assumption that complete mixing occurs during
the flood tide, an approximation which can be used reasonably
only for relatively small, shallow bays like the three
treated above. Thus no attempt is made to reproduce the
concentration isopleths, in direct contrast to the computer
model. The implicit assumption that the surface area of a
natural body of water remains constant over a tidal cycle
introduces yet another source of error. Another underlying
assumption in these calculations is that the concentrations
of pollutants are at a steady state. While this may be true
over short time intervals or in a time-averaged sense,
seasonal and even weekly variations in the tides and river
inflow may cause significant discrepancies between the
computed concentrations and observed values of background
concentrations. The method is valid as a means of arriving
at an order of magnitude approximation to the average back-
ground concentrations of contaminants in relatively small,
shallow estuarine bays.
Barney Barrett, Cooperative Gulf of Mexico Estuarine
Inventory and Study, Louisiana, Phase II Hydrology, and
Phase III Sedimentology (New Orleans: Louisiana Wildlife
and Fisheries Commission, 1971), p. 55.
-301-
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TABLE B-l
COMPUTED FLUSHING TIMES AND STEADY STATE DILUTION FACTORS
FOR OIL FIELD BRINE DISCHARGES IN BARATARIA BAY
NAME OF BAY
HACKBERRY BAY
LAKE WASHINGTON
MUD LAKE
V AREA VD
(M3) (M2) (M3)
l.SOxlO7 1.78xl07 9,747
2. 64x1 O6 5. 78x1 O6 508
1.47xl06 3.22xl06 368
T
(TIDAL PERIODS)
8.30
3.43
5.57
2.52
5.57
2.52
DILUTION TIDAL
FACTOR HEIGHT
5.5xlO"3 .1M
1.8xlO"3 .3M
8.8xlO"4 .1M
2.9xlO"4 .3M
l.lxlO"3 .1M
3.6xlO"4 .3M
I
OJ
O
to
I
-------
B.3 General Fluid-Dynamic Considerations for Open Bodies
of Water
The assumption of uniform mixing employed in the tidal
flushing calculations described in Section B.2 rules out the
possibility of predicting concentrations contours around the
discharge point since averaging pollutant concentrations
over the entire receiving waterbody volume does not give any
information concerning concentration gradients. For large
bays and estuaries, especially, uniform mixing is not a
reasonable or useful assumption, since the averaging process
will effectively mask the existence of localized areas of
relatively high concentrations. The impact resulting from
brine discharges depends on the extent to which regions in
the receiving waterbody are subjected to particular levels
of pollutant concentration, and these pollutant concentration
levels vary with distance from the brine discharge sites.
The prediction of pollutant concentration contours requires
a level of modeling more sophisticated than that of the tidal
flushing model. A very useful approach to the problem of
predicting pollutant concentrations in the receiving water-
body is to apply the physics of fluid dynamics to modeling
the actual diffusion process responsible for the dispersion
of concentrated effluents. This kind of analysis yields
concentration distributions instead of averages. Thus,
diffusion modeling generates a more desirable (i.e., more
informative) type of output than the tidal flushing calcula-
tions, provided the former is applied in a regime where it
is valid. Large bays are valid regimes because there is room
enough for a variety of current scales — a condition which,
as will be explained, is essential to the estimation of a
natural diffusion rate.
The problem of interest here is what happens to a
parcel of brine containing pollutants when it is subjected
to a field of currents in an estuary. Where does it go?
How fast is it diluted? What area contains concentrations
which are worthy of concern? To answer these questions, it
is necessary to analyze the actual current fields themselves.
Water currents can be examined at various scales, and the
scale chosen determines to what extent the curvature of the
streamlines, or directions of fluid flow, is significant.
Since logically one chooses the scale of analysis to fit the
size of the pollutant stream, which is constantly expanding,
it is necessary to consider several different ways of viewing
currents.
If the scale is small compared to the streamline curva-
ture, i.e., if the pollution stream is small compared to the
-303-
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distance over which the current remains relatively uniform,
then the current will not disperse the pollutants very much.
Rather, it will tend to carry them more or less intact along
the overall direction of flow. This situation, illustrated
in Figure B-2, is often described by saying that the charac-
teristic eddy of the current is much larger than the pollu-
tant stream, and the resulting transport is called advection.
On the other hand, if the characteristic eddy is
smaller than the pollutant stream, the pollutants will be
subject to several different directions of flow over any
small period of time. The resulting transport pattern,
illustrated in Figure B-3, tends to disperse the pollutant
parcel. This situation is often described by saying that
turbulent flow causes more pronounced diffusion of the
pollutant stream. (The reason for the adjectives "more
pronounced" is that diffusion occurs on a molecular scale,
independent of any observable fluid flow. The component of
diffusion attributable to turbulence is usually called "eddy
diffusion.")
Modeling this process of diffusion offers a convenient
framework in which to analyze the tendency of pollutant
streams to spread out after they enter the receiving water.
Pollutant streams are characterized by a range of concentra-
tions strewn about a volume of water in some fashion. For a
given stream, the function c(x,y,z) expressing the concen-
tration at each point (x,y,z) in the volume defines a
distribution of the pollutant; the degree to which such a
distribution is spread out in any direction (say y) is
measured by the variance,
/oo
y2d(x,y,z) dy (B-2)
-00
For a diffusing pollutant stream, the distribution is
continually spreading, so that the variance increases with
time. The rate of this increase indicates the rate of
diffusion, so that a very large part of the task of charac-
terizing a diffusion process is accomplished by defining a
diffusion coefficient E in terms of the time rate of change
in the variance (spatial spreading) of the pollutant stream:
4
Frank D. Masch, "Mixing and Dispersion of Wastes by
Wind and Wave Action," in Advances in Water Pollution Research,
ed. by E.A. Pearson (New York: Pergamon Press, 1964), p. 146.
-304-
-------
o
Cn
I
current streamlines
Figure B-2. Advection due to uniform, steady flow.
-------
I
(jj
o
en
I
current streamlines
Figure B-3. Diffusion due to turbulent flow.
-------
E - £ It (a2) (B-3)
Notice that E has the dimensions of area/time. The reason
for the factor 1/2 is that the variance a2 measures spatial
spreading in both the positive and negative directions
relative to the center of mass of the pollutant stream,
whereas it is customary in discussing diffusion mechanics to
measure dispersion in a given direction in terms of the
positive spreading only.
The analysis is complicated by the experimental fact
that the spreading rate (d/dt)(a2) of pollutant streams in
natural waters increases as the diffusion process progresses.
In other words, as the scale of the pollutant stream in-
creases because of diffusion, the rate at which further
diffusion occurs also increases, causing more and more rapid
dispersal. This observation can be explained in terms of
the turbulent effects discussed above. When a pollutant
stream is small in scale, only currents with comparatively
small characteristic eddies can be considered turbulent with
respect to the stream. Two representative particles moving
in such an eddy will tend to have very similar trajectories
because of their proximity to each other, so that they will
not be separated quickly at this small scale. As the scale
increases, the degree to which the motions of two represen-
tative pollutant particles are correlated diminishes,
resulting in a more rapid overall rate of separation.^
Therefore, the eddy diffusion coefficient E is a function of
the scale (i.e., the largest dimension) L of the parcel
formed by the pollutant stream. Empirical studies have
found that a reasonably accurate expression for the depen-
dence of E on L is given by a power law such as
E = aL4/3 (B-4)
where a is an empirically determined constant.
Several observations about Equation (B-4) deserve some
attention. To begin with, there remains considerable contro-
versy over the accuracy to which eddy diffusion coefficients
can be evaluated. It is likely that different flow and
depth regimes are best characterized by different diffusion
Henry Stommel, "Horizontal Diffusion Due to Ocean
Turbulence," Journal of Marine Research 8 (1949): 199-225.
-307-
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laws. The 4/3 law in (B-4) fits data for ocean regimes sum-
marized by Pearson^ and has been used in many investigations
of ocean diffusion.
The second observation is that eddy diffusion, as
defined by (B-4), is nothing more than a sort of statistical
construct devised to alleviate the difficulties encountered
in solving differential equations for complicated velocity
fields. Analysis at the microscopic scale would involve a
set of equations of motion tracing the path of each minute
parcel of the pollutant as it moved through a current field
which varied both spatially and temporally in a complicated
and irregular way. Such problems are hopelessly intractable.
The saner approach normally taken for eddy diffusion is to
view the background current field from a macroscopic stand-
point, taking into explicit account only the major features
of speed and direction of the flow. So that the important
dispersing effect of the irregular details (turbulence) of
the current fields is not thereby ignored, it is modeled by
lumping all of the eddy-diffusive flow characteristics into
a single factor representing, in a sense, their aggregate
effect on the pollutant stream. This factor is the non-
molecular diffusive component of the eddy diffusion law
given in (B-4). The justification for the form of such a
simplifying assumption must be provided by actual empirical
studies verifying that the hypothetical law accurately
models the measurable behavior of dispersing pollutant
particles in real bodies of water.
This last point is related tOythe third observation
regarding Equation (B-4). Stommel and others have empha-
sized two approaches to eddy diffusion laws, one "inductive"
(empirical) and the other "deductive" (analytical or theore-
tical) . The inductive approach consists in observing the
scale dependence of the diffusion rate and then calculating
the functional form of this dependence on the basis of field
measurements. The deductive approach consists in deriving
the functional form from one or more diffusion theories from
physics. Stommel, for example, demonstrates the derivation
of a 4/3 law from both the Weisaecker-Heisenberg postulates
N.H. Pearson, An Investigation of the Efficacy of Sub-
marine Outfall Disposal of Sewage and Sludge, No. 14, State
Water Pollution Control Board Publication, Sacramento, Cali-
fornia, 1956.
Stommel, "Horizontal Diffusion," pp. 199-225.
-308-
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and the Kolmogoroff postulates. He cautions, however, that
the empirical approach possesses a more solid foundation in
fact, whereas the theoretical considerations are more useful
in finding an explanation of observed diffusion phenomena in
terms of more fundamental physical laws. This caveat is
important in light of the fact that several successful
studies of eddy diffusion have deviated from the 4/3 law,
reflecting the view that empirical description, rather than
theoretical explanation, is the overriding concern of
engineering modeling studies.
The next step in modeling ocean diffusion is to produce
a mathematical expression of the physical relationships
which govern the process. The basic principle behind dif-
fusion mechanics is that the mass of the pollutant must be
conserved in the absence of decay. The simplest situation
in which this principle can be applied is also perhaps the
most illustrative: it concerns the lateral diffusion of
pollutants in a longitudinal current field which is uniform,
i.e., horizontal diffusion perpendicular to the direction of
current flow. Implicit in this statement of the problem is
the assumption that it is in fact realistic to absorb the
turbulent, non-advective velocity components of the flow
into the eddy diffusion coefficient, leaving explicit only
the hypothesized steady and uniform component. It should be
noted also that the problem as stated ignores diffusion in
the direction of flow and vertical diffusion through the
water column.
The conservation of mass for this problem means that
the time rate of change of the pollutant concentration
around every point (x,y) must be accounted for completely by
variations in< the net flux of concentration into or out of
the volume element containing (x,y). In mathematical
language,
oT = ly (E ff> = ly [flux in the y direction]
Expanding the total time derivative of the concentration
(left side) using the chain rule gives
3t 8t 8x 8t 3y 3y 8y
But the problem as stated indicates no explicit dependence
of c on the time (although there is implicit dependence,
since diffusion depends directly on distance traveled, which
in turn depends on time); also, the axes have been chosen so
that there is no component of the current velocity lying in
-309-
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the y direction. The first of these considerations forces
3c/3t = 0; the second implies 3y/3t =0. By hypothesis, the
velocity of pollutants in the x direction (i.e., 3x/9t) is
the current speed U. All of these observations reduce the
equation to
0 If - k (E-5)
The term on the left in (B-5) represents the advective
transport of the concentration gradient along the x-direction;
the term on the right represents the local spatial variation
of the concentration flux in the lateral (y) direction.
This equation, along with its higher-dimensional analogues,
serves as the basis for the plume model.
B.4 Plume Dispersion in a Steady Uniform Current
The model to be described in this section is an analy-
tical method for predicting the dispersion of a pollutant
plume in a steady uniform current. This model is applicable
to situations in which tidal current oscillation can be
neglected compared to a steady current flow in a specified
direction. The model is thus suitable for simulating the
dispersion of brine that is discharged into waters in the
Gulf of Mexico sufficiently far offshore so that tidal
currents are insignificant. For the Louisiana bay area or
for Cook Inlet, where tidal currents play an important role
in the dispersion of discharge, a model that can incorporate
temporal variation of current is needed. Such a model will
be discussed in Section B.5.
The problem analyzed in some detail below is shown in
Figure B-4. The method used here is essentially that of
Brooks. A discharge orifice width (diameter) b is located
at x=0 in a constant ocean current U in the x-direction.
After the initial concentration CQ of the pollutants has
been established just beyond the point of discharge, the
pollutant stream is swept downstream with the current speed
U. As it travels, dispersion in the y-direction occurs, so
that the scale L of the pollutant stream increases with
Q
N.H. Brooks, "Diffusion of Sewage Effluent in an Ocean-
current," Proceedings of the First International Conference
on Waste Disposal in the Marine Environment held at the
University of California, Berkeley, July 22-25, 1959, ed. by
E.A. Pearson (New York: Pergamon Press, 1959), pp. 246-267.
-310-
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Ocean Current
Discharge
Orifice
c(x,y)
T
Initial
Concentration
co
Figure B-4. Lateral diffusion from discharge in a steady,
uniform current field U.
-------
increasing x. The concentration of pollutant at any point
(x,y) in the plane will be denoted by c(x,y) and, from the
discussion above, will be governed by (B-5) along with the
appropriate boundary conditions at the point of discharge
(x = 0) :
1. If |y| < b/2 then c(0,y) = CQ [the initial
concentration]
2. If |y| >_ b/2 then c(0,y) = 0
The following assumptions are necessary to simplify the
analysis:
1. There is no variation in the vertical direction.
This assumption limits the applicability of the
model to the cases of (1) uniform mixing through-
out the water column, and (2) no vertical mixing
(as a result, for example, of a pronounced density
stratification not uncommon in estuaries) in which
case the analysis can be applied to the dispersion
of a pollutant in a particular layer of the water
column.
2. Diffusion in the direction of the current (the
x-direction) is negligible compared to the current-
induced advection.
3. U is constant in time and uniform, so that the
diffusive effects of all eddy currents are ac-
counted for by the diffusion coefficient E. This
assumption has the effect of limiting the validity
of the analysis to a region within which the
instantaneous spatial variations of current speed
and direction are small.
4. The diffusion coefficient depends spatially only
on the scale of the pollutant stream, which in
turn is a function of the distance x over which
the current (including turbulence) has had a
chance to disperse the stream.
The fourth assumption allows an immediate simplification of
equation (B-5): spatially, E is a function only of x, so
E(x) L-| = u || (B-6)
9y
-312-
-------
This is very nearly the form of a classical partial differ-
ential equation known as the heat equation, except that E is
a nonconstant function of x. Since the heat equation has
been solved for a multitude of problems, it is advantageous
to manipulate (B-6) until it can be solved via the simpler
equation.
To begin with, define EQ to be the value of E(x) when
x = 0, so that
E(x) = EQ f(x)
and therefore Equation (B-6) can be written
E
iJE.
0 , 2
3y
U 9c
f(x) 3x
(B-7)
From here it is a relatively easy matter to "hide" the
x-dependence in the coefficient on the right hand side
behind a change of variables: define a new "diffusion
distance" £ by
•L
x
f (w) dw
(B-8)
Then
By the chain rule, (B-7) can be written in terms of E, as a
heat equation:
,
By
U_
E,
(B-9)
The solution to this equation has been derived many times;
Carslaw and Jaeger's volume is almost entirely concerned
with it. The solution which fits boundary conditions (a)
and (b) is a form of Laplace's solution for an infinite
solid^ (see the supplement to this appendix):
H.S. Carslaw and J.C. Jaeger, Conduction of Heat in
Solids (London: Oxford University Press, 1959), pp. 53-56,
-313-
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b2
- erf
(B-10)
At this point it is useful to clear up a question
regarding the scale parameter L. Since the extent of the
nonzero portion of c is infinite in both the positive and
negative directions for all x > 0, it is pointless to .define
L as the boundary of the nonzero concentration. Rather, L
will have to be defined in terms of the width parameter
defined for the concentration distribution by Equation (B-2).
Thus L will establish the boundary defined by the distribu-
tion of a certain percentage of the pollutants clustering
around the line of greatest concentration, y = 0. For
convenience, L might as well be chosen so that it will equal
b at x = 0. At this point, Equation (B-2) reduces to
y^» —OO
a (0) = -~ / y2c(0,y)dy =
cnD J~*
b/2
\
-b/2'
C0dy = 12"
u L
Hence,
a(0) =
2/3
So the
expression L = 2/3~ satisfies the stipulation L(0) = b.
The relationship between L and a can be used to deter-
mine £ as a definite function of x, which is precisely the
information needed to convert (B-9) and (B-10) to a solution
c(x,y). Recalling the definition of the diffusion coef-
ficient E, (B-3) yields
Id ,2. _ 1 d /L2
-"2dT(a) * 2" 3t \I2
An appeal to the chain rule converts the time derivative to
the x-derivative :
24
if
3* fx
since the speed dx/dt of the pollutant stream is assumed to
be the current speed U. Differentiating L^ then gives
„, . UL dL
E(x) = 12 dlT
-314-
-------
But the function f(x) defining the relationship between x
and £ is just E(X)/EQ, and from Equation (B-4)
E(x) _ FL(x)l
" -
.4/3
Hence,
4/3
UL dL
12EQ dx
i.e. ,
dL
dx"
12EOVL\1/3
(B-ll)
This equation is a version of Bernoulli's equation, and its
solution (see the supplement to this appendix) is:
3/2
12E
0
3b
Ub
This solution indicates that the functional relationship
between £ and x is determined by
f(x) =
4/3
= 1 +
2Bx
3b
Now the solution to the diffusion equation given in (B-ll)
may be evaluated in terms of x instead of £, using the
relationship (B-8) to get
i - JL.
b 26
(B-12)
The final solution, therefore, may be summarized as follows:
c,x,y, .
where
Y =
being given by (B-12)
-315-
-------
The value of this analysis is threefold. To begin
with, the results given in (B-9) in combination with (B-12)
are applicable to far-offshore discharges into an approxi-
mately steady, uniform current regime. Second, the numeri-
cal values obtained for special problems by using (B-9) and
(B-12) can be used to check the computer program used to
solve the more complicated three-dimensional diffusion
problem encountered for nearshore discharges. Third,
several qualitative conclusions may be drawn from the
foregoing analysis regarding the nature of the concentration
distribution. Among these are:
1. The diffusion equation for ocean dispersion can
be solved as a modified form of the classical heat
equation. The solution indicates, that after the
initial concentration at the discharge point has
been established, pollutants are distributed in
the lateral direction according to an expression
involving the error function. This distribution
spreads as the pollutants travel downstream.
2. The scale of the pollutant stream, measured in
terms of the variance of its spatial distribution,
expands slightly faster than the 3/2 power of the
distance travelled (see Figure B-5) .
3. As a result of the spreading, the concentration at
the center of the pollutant stream decreases as
the stream travels, approaching zero asymptotic-
ally with increasing distance from the discharge
point (see Figure B-6) .
B. 5 Plume Dispersion in an Unsteady Uniform Current
B.5.1 Introduction
The model to be described in this section is an analyt
ical model for predicting the dispersion of a pollutant
plume in a transient but spatially uniform current. This
model is applicable to situations in which current variabil
ity is important but in which the assumption of a uniform
current is acceptable, at least for the portion of the
receiving water that is of primary interest. The model is
essentially the Transient Plume Model described by Adams et
' E. Eric Adams, Keith D. Stolzenback, and Donald R.F.
Harleman, Near and Far Field Analysis of Buoyant Surface
Discharges into Large Bodies of Water, Report No. 205, Ralph
M. Parsons Laboratory for Water Resources and Hydrodynamics,
Department of Civil Engineering, Massachusetts Institute of
Technology, August 1975.
-316-
-------
I
U)
•f !_ L
2 b
L=SCALE=2>J3 o
E=EDDY DIFFUSIVITY
12E
Figure B-5. Plot of pollutant stream scale as a function of distance
travelled.
-------
o
*
X
CJ
1.0
u 0.8
§
H
EH
23
W
O
g
O
g
H
X
ss
0.6
0.4
0.2
0.1
0.08
0.06
(
V
\
)
\
\
\
3'
\
\
1? 1
Ub
\
?
t
\
4
R
Ea
\
-
\
5
«i
r L i
b}
\
^
/3
V
\
g
^
N
1
Figure B-6. Plot of centerline (maximum)
concentration as a function of distance travelled.
-318-
-------
which was developed to predict water temperatures near a
proposed offshore power station. More recently the model
has been used to analyze the far field temperature distri-
bution associated with power plants sited on Lake Ontario
and Cayuga Lake.H
B.5.2 The Governing Equation for the Far Field
The principle of mass (or heat) conservation applied to
a differential control volume leads to a governing equation,
the convection-diffusion equation, for the concentration of
the effluent. In the coordinate system in Figure B-7,
this equation and its boundary conditions may be expressed
as
3c 3c
3t U3x
c(x,y,z,t) is the concentration of the effluent; u, v, and
w(x,y,z,t) are the x, y, and z components of the velocity
field; Ex, Ey, Ez(x,y,z,t) are turbulent "eddy-diffusion"
coefficients; K^ft) is a first order decay coefficient (via
radioactivity, chemical reaction, etc.); qs and q^ are
transport rates across the surface and the bottom respec-
tively (positive values of qs and qt, imply transport of
effluent out of the liquid volume); and H(x,y,t) is the
water depth.
Instead of solving for the actual concentration c from
Equation (B-13), the present model solves for excess concen
tration (the difference in concentration observed with and
without the effluent discharge) by writing a similar equa-
tion (with boundary conditions) for the concentration of
Keith D. Stolzenbach et al., Analytical and Experi-
mental Studies of Discharge Designs for the Cayuga Station
at the Somerset Alternate Site, Report No. 211, Ralph M.
Parsons Laboratory for Water Resources and Hydraulics,
Massachusetts Institute of Technology, May 1976.
-319-
-------
effluent in ambient water and subtracting it from Equation
(B-13). The result is a third equation (with boundary
conditions) of the same form as Equation (B-13) for the new
variable
Ac = c - c , (B-14)
amb.
Several simplifications are made to reduce the equation
to a form yielding tractable solutions.
First the velocity field is considered to be two-
dimensional (w = 0), horizontally uniform, and vertically
sheared (with arbitrary shear distribution). Thus
u = u(t) + u" (z,t)
(B-15)
v = v(t) + v"(z,t)
where u(t) and v(t) are instantaneous depth averaged veloci-
ties. Because there is no horizontal variation of velocity,
the assumed velocity field may be ascertained from a time
series of currents measured at one station (vertical water
column).
Second, because a solution is to be obtained by super-
position of instantaneous sources, horizontal diffusion is
described by "relative diffusion coefficients." For hori-
zontally homogeneous, stationary turbulence the magnitude of
these coefficients depends only on depth and the size of the
diffusing patch. The size is described by the horizontal
standard deviations, ox and ay. Thus,
(B-16)
Ex = Ex(z'ax)
Ey = VZ'V
The vertical diffusion coefficient is assumed to be a
function of z only.
Finally, the water depth, H, is assumed to be constant.
Using the concept of excess concentration and the above
simplifications, Equation (B-13) may be rewritten as
-320-
-------
[u(t)
[v(t) +v"(z,t)]
8Ac
3Ac
3Ac
KsAc,
z = 0
(B-17)
-KbAc, z = H
B.5.3 Solution for an Instantaneous Vertical Line
Source
The excess concentration at time T caused by a verti-
cally distributed line source instantaneously released at
time T is sought. The first step is to transform to a
coordinate system moving with the mean current velocity:
= x
= y
f\
(t)dt - x
0
r
v(t)dt -
(B-18)
Equation (B-17) is rewritten as
3Ac , .,3Ac _.,3Ac _
- -
9Ac
3z
K Ac,
s
z = 0
-KbAc, z = H
(B-19)
Equation (B-19) is solved for an instantaneous release
by the method of moments. Each term of the equation is
multiplied by
i i
xryr
and integrated over the domain -°° < xr, yr < °°, to obtain
equations for the moments c^-; (z, t,T) . For instance, for
-321-
-------
i=j=0;i=l,2,3, j=0; and j = 1,2,3, i = 0, the
following seven equations are derived:
where
3c
00
9t
3c
01
3z\z 3z
^ / 3c
3t
3c
v"c
01
00
10
4z 9z
9cn ,
3t
u,,c
_
00 3z\ z 9z
3c.
3c
- 2u"c,rt = 2E cnn
10 x 00
20
9c,
z 3z
3crt.
'30
3t
3c
03
3c,
3v"C02 = 6EyC01
(B-20)
oo .,00
/"J /* •
/ Acx^yjdxr
— OO *^ —OO
(B-21)
The boundary condition associated with each equation in
(B-20) is
Z =
'z 3z
(B-22)
-Kbcijf
Equations (B-20) are weakly coupled and can be inte-
grated numerically in the order in which they are presented
from t = T to T. Initial conditions (for an instantaneous
release at t = T) are:
r> —
~
M_(z) , i = j = 0
(B-23)
0,
or j ? 0
-322-
-------
where mz(z) is the mass released per unit depth at depth z.
In the computer program, Equations (B-20) are made non-
dimensional and are solved using finite difference with a
Crank-Nicholson time scheme.
Familiar statistics describing the distribution of the
instantaneously released effluent patch can be derived from
the moments c.:-;. For example
x" =
y" =
'10
:oo
'01
:oo
(B-24)
a =
a =
a =
'20
:oo
'02
:oo
'03
;00
'10
2
'00
2
:oo
00
3c
01C02
"00
2c
01
'00
x
a =
C30
coo
3c10°20
2
coo
, 2cio
°l*
(B-25)
(B-26)
x" and y" are the xr and yr coordinates of the centers of
mass of the patch excess concentration distribution,
2 j 2
ax and Cy
are the variances (squares of the standard deviations) of
the patch distribution, and ax and ay are skewness coeffi-
cients. A large number of moments are necessary to accu-
curately describe a single patch. However, when a number of
-323-
-------
point source solutions are superimposed to form a continuous
solution, it is reasoned that the Oth, 1st, and 2nd moments
for each patch are sufficient to approximate the continuous
plume. That is, each skewed patch is replaced by a Gaussian
patch with the same Oth, 1st, and 2nd moments. The peak
concentration of this Gaussian patch is
2002
and the approximate excess concentration distribution at
time T after release at time T is
cinst(xr'yr'z'T'T) =
(z,T,T)exp
[x - x"(z,T,T)]
5
2<(z,T,T)
x
[y - y"(z,T,T)]
2(T(z,T,T)
y
(B-28)
B . 5 . 4 Solution for a Continuous Release of Finite Size
The far field plur.ie shown in Figure B-7 can be gener-
ated by a set of continuously emitting vertical line sources
of effluent distributed across the cross section illustrated
in the main diagram below. Concentrations can be obtained
by integrating Equation (B-28) from T = 0 to T and over the
width of the source from y' = B/2 to y ' = B/2. A weighting
factor, my(y'), is used to adjust the strength of the
vertical line sources to match the observed (from a near
field analysis) lateral distribution of concentration.
/-TV B/2
c(x,y,z,T) = / / c. (x ,y ,z,T,T)m (y')dy'dT
J0 J -B/2 Y
(B-29)
In practice the above integrations are replaced by a
finite series (summation) using NI laterally distributed
instantaneous sources at each time step and NT time steps
-324-
-------
Virtual Origin(X ,0)
H
X
Discharge Point
Prescribed Initial Conditions
from Near Field Solution:
QoD
1
DAcc
i , ,*i
Ac
= 1
_ 1
Figure B-7 . Far field source conditions. (E. Eric
Adams, Keith D. StolzenbacJ;, and Donald R.F. Harleman,
Near and Far Field Analysis of Buoyant Surface Discharges
into Large Bodies of Water,. Report No. 205, Ralph M. Parsons
Laboratory for Water Resources and Hydrodynamics, Department
of Civil Engineering, Massachusetts Institute of Technology,
August 1975.)
-325-
-------
NT NI(T,t)
c(x,y,z,T) = FACTOR cinst(xr'yr'Z'T'T)my
t=l n=l
Qn(x)Acn(T)AT(T,T)
FACTOR = NI(T,T)H - (B'30)
where QQ is the initial (discharged) flow rate and Acg is
the initial concentration or temperature rise (without
recirculation) . Also, the initial conditions for C20 and
CQ2 in Equation (B-23) are altered to represent a partially
developed patch; i.e., one which was "effectively released"
at a previous time and position such that it has migrated to
the source location and has grown to a finite size by the
time t = T. Thus a smooth concentration distribution can be
achieved near the source.
B.5.5 Source Conditions
The characteristics of the far field source of pollu-
tant are determined as follows with reference to Figure B-7.
First, the source is assumed to be displaced a distance xj_
to account for the possible length of the steady state
portion of the mixing zone. (The coordinate system is
assumed to be chosen such that the discharge is in tne
positive x direction.) Secondly, the remaining portion of
the mixing zone is assumed to have a length RTRANS and to be
oriented in the direction of the prevailing current direc-
tion. Next, the initial source is assumed to be distributed
evenly over a portion H2 of the total depth. Finally, the
discharge flow is assumed to be mixed with the receiving
water in an amount given by the dilution, D, which is the
ratio of the mixed flow to the initial flow.
With the above information given, the width, B, of the
source is determined by the following mass continuity
relationship :
DQQ
B = - V- (B
HV
where Qfl = the initial flow
|v| = magnitude of the current speed
-326-
-------
B.5.6 Form of Horizontal Diffusion Coefficients
Horizontal diffusion of each patch is described by
relative diffusion coefficients, Ex and Ey, that are related
to the size of the patch by:
n_
E = Aa
x x
X
a < a
x xc
E = Aa x
X XC
E = Aa
y
E = Aa
n
Y
y
n
y
'yc
a > a
X XC
a < a
y
a > a
y
(B-32)
The form of Equations (B-32) suggests that over a certain
range of length scales (a < ac) patches undergo "accelerated
diffusion" due to current shear effects, while for large
length scales (a > ac) diffusion is more accurately (or
conservatively in the absence of data) described by constant
diffusion coefficients. From Equations (B-3) and (B-32) it
follows that
2~nx 2'nx
ax(T'T) =axO(T) + (2 - nx)A(T - T)
2-n
2-n
ay(T,T) y = ay0(T) y -f
a (T T)2 - a2 + 2Aanx
w VL/J./ \J i a
X XC
a (i,T)2 = a2 + 2Aany
y yc yc
T - T -
2-n 2-n
a y - a n(T)
yc yO
(2 - Ny)A
a > a
y
-327-
-------
B.5.7 Shoreline Imaging
When the discharge is located near a straight shore-
line, two constraints must be imposed. First, the currents
must be assumed to flow parallel to the shoreline to prevent
advection of the pollutant mass across the boundary.
Secondly, to prevent effective diffusion across the boun-
dary, an image source corresponding to each real source is
assumed to be located on the opposite side of the shoreline.
B.5.8 Summary of Model Parameters
The model described in the previous section requires
the specifications of the following parameters:
Q_ = initial discharge flow
Acn = initial discharge excess concen-
tration
D = initial dilution
x, = initial fixed mixing distance
H~ = initial depth of source
RTRANS = initial variable mixing distance
H = total water depth
XSHORE = distance to shoreline (if appli-
cable)
u(t),v(t) = horizontal components of velocity
as a function of time
k-,,k ,k, = internal, surface, and bottom decay
coefficients
E = vertical diffusion coefficient
z
A ,A ,n ,n ,a 'avc = parameters describing the hori-
Y Y v zontal diffusion coefficients
-328-
-------
SUPPLEMENTS TO APPENDIX B
LAPLACE'S SOLUTION TO THE HEAT EQUATION12
This section examines in detail the solution of the
heat equation (B-9) given in Appendix B, Section B.4:
(a-l)
(
-
ay2 Eo K
given the boundary conditions
if y < b/2
0 if y >_ b/2
for a finite line source. The method of solution employed
here is typical for problems involving spatially continuous
sources in that it considers a continuous source to be a
collection of point sources each contributing to the total
solution. A refined version of this method is used in the
computer model developed by Adams et al.
The solution to Equation (a-l) is most easily found by
appealing to the superposition principle: since the equa-
tion is linear, the solution corresponding to a line source
from y = -b/2 to y = b/2 is just the superposition (i.e.,
the sum or, ,for continous sources, the integral) of the
solutions for the point sources comprising the line. The
equation describing a point source at (0,y') is just (B-8) ,
with the boundary condition being given by the conservation
of mass principle: if the initial discharge at (0,y') is
such that the resulting average concentration on the unit
area surrounding it is CQ , then for any value of C /
c = f c6(C,y)dy (a-2)
^—
where eg is the point source concentration. It is easily
checked that
G.T. Csanady, Turbulent Diffusion in the Environment
(Dordrecht, Holland: D. Reidel Publishing Co., 1973),
Chapter 1.
-329-
-------
c =
exp
-(y - y')2
A
= — exp
4(EQ/UK
-(y - y')2
4EQT
(a-3)
is a solution to (a-1) for all C > 0; the arbitrary con-
stant A can be evaluated by imposing (a-2) :
= 2A/TTEQ/U
Therefore,
and the point-source solution is
,y) =
2/TTEQT
exp
-(y - y1)
. 4V
Integrating c§ over all points constituting the line segment
-b/2 < y < b/2 gives the solution for the line source:
-b/2
exp
-(y - y')
4EQT
dy'
(a-4)
By the definition
erf(w) = — / exp(-z )dz
/if -^ 0
of the error function, (a-4) can be written as
/y - b/2'
(B-10)
-330-
-------
SOLUTION TO BERNOULLI'S EQUATION
The equation (3-5)
dL .
dx" ~ l~Ub~llcr ' (b~1}
is more readily recognized after a change of variables
A = L/b, x = x/b
and a renaming of constants
12EQ
(dimensionless)
Ub
These simplifications throw (b-1) into the form of Ber-
noulli's equation:
-------
The initial condition requiring that L = b at x = 0 is
sufficient to determine that the constant C of integration
is equal to unity; therefore,
L _ / 2 x\3/2
b ~ 3
-332-
-------
APPENDIX C
FATES OF HYDROCARBONS AND TRACE METALS
IN THE MARINE ENVIRONMENT
C.1 Introduction
A central assumption of the analysis performed in this
report is that the key process leading to the observed con-
centrations of oilfield brine constituents in the vicinity
of a production platform is the dilution of the brine due to
diffusion forces and current patterns. Thus, it is assumed
that the spatial distributions of brine concentrations
around a platform are adequately represented by the predic-
tive model described in Appendix B, which takes only currents
and diffusion into account. This is an excellent approxi-
mation, but it is not the complete story. The components of
oilfield brines are subject to a number of physical, chemical,
and biological processes other than dilution, which can all
affect their physical form, chemical nature, and, therefore,
their toxicity.
Fundamentally, there are three types of relevant pro-
cesses :
1. Degradation processes, such as the microbial or
photo-degradation of hydrocarbons in the marine
environment.
2. Alteration processes, such as the biological
methylation of mercury or the oxidation of Cu+
ions.
3. Transfer processes, which move the pollutant from
one compartment of the marine environment to
another (e.g., the transfer of metals from the
water column to the bottom sediments via precipi-
tation and sedimentation).
Generally, data are not yet available which would
enable these effects to be incorporated in any reliable way
in a theoretical or semi-empirical predictive model. Further-
more, actual data on the rates of these processes in situ
is rare, and only one or two studies have reported actual
metal or hydrocarbon monitoring data in the vicinity of
production platforms. Therefore, these processes will not
-333-
-------
be incorporated into the primary analysis of this report.
Nevertheless, the more important of these processes are
discussed in this appendix to indicate their approximate
rates and the qualitative way in which they might affect
brine toxicity.
One of the most important of these environmental modifi-
cation processes, and one to which both hydrocarbons and
trace metals are subject, is sedimentation. The transfer of
a toxic substance from the dissolved to the suspended or
settled fraction of the marine environment drastically
affects its accessibility to resident organisms. On a_
priori grounds, for example, one might expect precipitation
and sedimentation processes to decrease the toxicity of
metals and hydrocarbons to most swimming fish, but to create
a much more severe toxicity problem for benthic or filter
feeding organisms, and to a large extent these conclusions
are supported by the literature. (Sedimentation is an ex-
ample of a process which alters toxic impact by affecting
the accessibility of a substance. Other environmental modi-
fication processes, such as oxidation of trace metals, can
affect toxicity more directly). Because of the importance
of sedimentation, it will be given primary emphasis in this
appendix.
C.2 Sedimentation
In general, sedimentation in estuaries occurs as a result
of the aggregation and settling of suspended particulates.
Two major processes have been proposed to explain this
aggregation for general particles: salt flocculation and
agglomeration by organisms. Settling is due to a number of
factors including net transport of suspended sediments from
swift river currents to calmer bays (the last is important
in estuaries and is highly dependent on the hydrological
nature of the estuary in question).
The principle behind salt flocculation is that the
presence of salt ions in water results in an electrolytic
effect which increases the tendency of suspended particles
to adhere to one another. Flocculation can be regarded as
the result of two separate mechanisms: .interparticle colli-
sions and cohesion between particles which have been brought
into contact with each other. Fine-grained suspended sedi-
ments tend to acquire small amounts of electrical charge as
they are buffeted about in the water, and, since similar
particles tend to pick up the same kind of charge, small
repulsive forces develop which inhibit the cohesion phase.
-334-
-------
The ions in electrolytic saline water act to neutralize
these small friction-generated charges, increasing the
probability of cohesion.1
The rate at which flocculation occurs depends on a
number of interacting variables, the most important being:
1. Relative distribution of mineral components
in the sediments.
2. Particle size (the electrochemical forces
causing floes are too small to have noticable
effects on clay particles much larger than about
ly).2
3. Salinity.
4. Suspended sediment concentration.
5. Turbulence and water depth.
Thus salt flocculation is very difficult to analyze in any
quantitative manner. Although the mechanism has been studied
in detail under controlled laboratory conditions, there is
presently little evidence to support the widely held belief
that increased aggregation due to net particle transport up
the saline gradient is a substantial factor in estuarine
sedimentation.3
The second major aggregation process, agglomeration by
organisms, is largely the result of filter feeding activity
by oysters, copepods, clams, mussels, scallops, tunicates,
and barnacles. For example, oysters filter water through
their gills in order to extract food. The rejected material
is emitted in clumps loosely held together by mucus, and the
A.T. Ippen, ed., "Sedimentation in Estuaries," in
Estuary and Coastline Hydrodynamics (New York: McGraw Hill,
1966), pp. 648-672.
2
Ippen, "Sedimentation in Estuaries."
R.H. Meade, "Transport and Deposition of Sediments in
Estuaries," in Environmental Transport of Coastal Plain Estu-
aries, Geological Society of American Memoir 133, ed. by
B.W. Nelson (Boulder, Colorado: Geological Society of
America).
-335-
-------
suspended matter that is eaten is agglomerated into small
fecal pellets. It is estimated that oysters can deposit
suspended matter at a rate seven or eight times of that
ordinarily caused by gravity.4 in estuaries where filter
feeders are a significant component of the trophic web,
organic agglomeration can be a substantial factor in sedi-
ment deposition.
The third process by which sedimentation of suspended
particulates may occur is due to the general hydrological
features of estuaries as compared to rivers. The currents
in a river are often strong enough to support a much greater
suspended sediment load than could be sustained by standing
water. In estuaries characterized by wide bays and sluggish
currents, the inflowing particulates may encounter less tur-
bulence than that provided by river flow and may sink as a
result. Naturally, the extent to which this process explains
sedimentation in a given estuary depends on the relative
turbulence of tidal and current flows in the estuary as com-
pared to the turbulence of the incoming, sediment-carrying
flow. Moreover, the extent to which this process applies to
oilfield brine discharges in the estuary depends on the
location of the discharge points with respect to the incoming
flow, i.e., whether brine is discharged into waters experi-
encing significant river currents, or into waters which are
already relatively calm.
C.2.1 Sedimentation of Oil-Associated Hydrocarbons
Most of the existing studies of oil species sedimenta-
tion focus on the fate of oil from accidental spills. Four
basic processes have been identified in the sedimentation of
materials from oil slicks:^
1. Evaporation and dissolution of lighter compounds.
2. Uptake of particulate matter (both organic and
inorganic) by petroleum.
4
Meade, "Transport and Deposition in Sediments in
Estuaries."
C.B. Gelelein, "Sedimentation Processes Involving
Hydrocarbons in the Marine Environment," in Background Papers
for a Workshop on the Inputs, Fates, and Effects of Petro-
leum in the Marine Environment, compiled by the Ocean Affairs
Board, National Academy of Sciences (Washington, B.C.:
National Academy of Sciences, 1973), pp. 462-466.
-336-
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3. Agglutination of dispersed globules followed
by the uptake of particulates.
4. Sorption of dissolved species onto suspended
particulates.
Of these processes, (1) is not particularly applicable to
oilfield brines, since they seldom contain large masses of
undissolved, unsuspended, and unevaporated oil species;
(2) is applicable only as it pertains to (3); (3) may be
applicable to brines containing significant amounts of
emulsified hydrocarbons following the oil-water separator
process; and (4) is likely to be an important mechanism for
hydrocarbon sedimentation from brines.
The uptake of suspended particulate matter by petroleum
globules is most important nearshore, where high concentra-
tions of suspended sediments frequently result from inflowing
river loads. The accumulated sediments increase the density
of the hydrocarbon mass, causing fairly rapid deposition
onto the ocean floor. There may be a biological contribution
to this process: oil-soaked suspended particles foster some
algal growth, which in turn, attracts small invertebrates.
The invertebrates attach themselves to the particles, again
increasing their density.6
It is likely that this process is preceded by some
agglutination of dispersed oil particles in the case of
oilfield brine, since the brine itself usually contains very
little oil in any substantially aggregated form. Because
the surface tension of a volume of water is inversely related
to surface curvature, oil dispersed in water tends to accumu-
late into larger aggregations with boundaries of smaller
curvature, thereby reducing the net potential energy of the
oil-seawater interface. (This process may be inhibited in
the well by higher temperatures.) The resulting increase in
volume enhances the uptake of suspended particulates and
hence the rate of deposition. This rate is also highly
dependent on the quantity of suspended particulates present,
turbulence of the receiving water, and the specific gravity
of the oil particles. For example, Bunker C oils and Venezuela
and California crudes with specific gravities very close to
carbons."
Gebelein, "Sedimentation Processes Involving Hydro-
-337-
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1.000 do not need to accumulate much particulate matter in
order to acquire the density necessary to sink.^
Dissolved species of oil enter the sediment phase pri-
marily via absorption or adsorption onto suspended particu-
lates. The most effective absorbers normally present in
estuarine waters are fine-grained clays of cross-section
less than about 45y. There is some indication that clays
with high organic content absorb oil species more effectively
than those with less organic matter. Also, in general,
sorption increases with salinity and decreases with tempera-
ture. 8
Very little is known about the actual rates of deposi-
tion associated with any of these processes. Research on
this problem is hampered not only by the lack of systemati-
cally conducted fieldwork but also by the fact that the
quantitative understanding of sedimentation gained in
controlled laboratory experiments cannot be used with any
confidence in applications to field studies in actual estuaries
The mechanisms by which deposited brine organics may become
resuspended also are not understood. It is thought that
reworking of sediments by tidal activity and by surface and
infaunal organisms may lead to resuspension.9 if this is
the case, then this same reworking may also lead to greater
longevity of oil-associated organics in estuaries. Biogenic
reworking of sediments may plow some organics down into the
anaerobic subsurface layers of the estuary floor, inhibiting
aerobic degradation. Despite the current lack of knowledge
concerning its mechanisms, however, sedimentation of oil
species is an important aspect of the long-term fate of oil-
field brine pollution.
C.2.2 Sedimentation of Metals
Oilfield brine generally contains appreciable concen-
trations of heavy metal ions. It is not surprising, there-
fore, that some of these metals find their way into the
National Academy of Sciences, Petroleum in the Marine
Environment (Washington, D.C.: National Academy of Sciences,
1975), pp.50-51.
g
National Academy of Sciences, Petroleum in the Marine
Environment.
9
National Academy of Sciences, Petroleum in the Marine
Environment.
-338-
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sediments of estuaries where brine is discharged. For
example, Montvalvo and Brady found higher levels of Zn, Cd,
Pd, and Hg in Louisiana bays harboring oilwell activity than
in offshore areas, with levels of Zn, Cd, and Pb substantially
higher near the rigs themselves.10 Of these three metals, no
correlation was found between Cd concentrations and depth;
however, Zn and Pb concentrations were highest in bottom
samples containing more sediment. These results indicate
that sedimentation should be considered an important fate of
certain heavy metals in discharged oilfield brine.
Several processes have been proposed to explain the
mechanisms by which metal ions are deposited on the bottom
of estuaries. Perhaps the most important of these processes
is adsorption onto suspended clay particles which eventually
sink to the estuarine floor. Rivers carry great quantities
of clays containing oxides of both manganese (MnOx) and iron
(FeOx).H These oxides exhibit an affinity for metal cations,
so that trace metal ions introduced into estuarine waters , „
fed by the rivers tend to be adsorbed onto the clay particles.
This process is influenced by the relative ion concentrations
as measured by pH and salinity, since increases in the
relative concentrations of lighter ions may displace heavier
absorbed cations, and vice versa for increases of heavy
metal concentrations. However, the wide variation in compo-
sition among different oilfield brines renders the extent to
which brine/seawater pH and salinity differences perturb the
adsorption by clays difficult to quantify.
J.G. Montavalo and D.V. Brady, Toxic Metal Determi-
nations in Offshore Water Samples, Final Report to Gulf
Universities Research Consortium, Contract No. GU 853-5,
Investigation No. OE-53-HJM, April 30, 1974.
K.K. Turekian, "Rivers, Tributaries, and Estuaries,"
Chapter 2, in The Impingement of Man on the Oceans, ed. by
Donald Hood (New York: John Wiley & Sons, 1971).
12
J.J. Morgan and R.D. Pomeroy, "Chemical and Geochemical
Processes Which Interact with and Influence the Distribution
of Wastes Introduced into the Marine Environment, and Chemi-
cal and Geochemical Effects on the Receiving Waters," in
Background Papers on Coastal Wastes Management, National
Academy of Engineering, Vol. 1 (Washington, D.C.: NTIS, 1969),
pp. X-l-X-44.
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-------
Chemical reactions resulting in precipitation are
another possible mode of metal sedimentation from brine/sea-
water mixtures. It has been suggested that many oil deposits
contain bacteria which reduce sulfate ions in brine to
hydrogen sulfide.13 Over long periods of time, this action
generates a solution which is highly reducing relative to
the comparatively sulfate-rich ocean environment. When the
two waters are mixed, sulfates in seawater oxidize certain
cations, often resulting in precipitation. The low concentra-
tions of sulfates in the brines produced from many Louisiana
wells!4 corroborate this hypothesis; however, the precipitates
formed are principally those of Ba, Sr, and Ca.15 Oxidation
by sulfates in seawater does not appear to be a significant
factor in the precipitation of heavy metals from discharged
brine.
A related process may explain, though, how heavy metals
introduced by discharged waters are precipitated when they
are not themselves present in heavy enough concentrations to
precipitate from aqueous solution. This process involves
the formation of a solid solution of heavy metals with the
more abundant solids dissolved in seawater. Discharging
oilfield brine into estuarine waters can be regarded as
mixing two aqueous solutions, each in equilibrium. If no
solubility changes result from this mixing, as in the case
of mixing two unsaturated aqueous solutions of NaCl, then no
precipitation will occur. However, it is likely that the
equilibrium configuration for some aqueous solutions containing
ions of both light and heavy metals consists of a solid
solution of heavier metals in some lighter ones,16 in equili-
brium with an aqueous solution. The solid solution may have
a lower solubility than its separate components, and hence
some precipitation may occur before equilibrium is reached,
even though none of the ions comprising the solid solution
would have precipitated were they to have remained in aqueous
Telephone conversation with A.G. Collins, March 31,
1976.
14
A.G. Collins, Geochemistry of Some Petroleum-Associated
Waters from Louisiana, U.S. Bureau of Mines Report of Inves-
tigations 7326, Washington, D.C., 1970.
Telephone conversation with A.G. Collins, March 31,
1976.
16
Morgan, "Chemical and Geochemical Processes."
-340-
-------
solution. Examples of such solid solutions are Ca(OH)2 in
Fe(OH)2, PbC>2 in MnC>2 and SrCO3 in CaCo3. Since the elements
in these complexes generally are not present in stoichiometric
proportions, the precipitates cannot be considered strictly
to have been formed via chemical reactions. Therefore this
mechanism may explain the sedimentation (formation of solid
phase) of trace metals for which distinct precipitate phases
in seawater appear thermodymanically unlikely.-^
Marine organisms also play a role in the long-term
deposition of trace metals. Organic debris and skeletal
fluorapatite in the deep-sea, or bathypelagic, zone are
known to accumulate trace quantities of Zn, Sn, Pb, Ti, Cu,
and Ag.19 Brown algae and plankton are also important bio-
accumulators of metals. Brown algae accumulate tetravalent
and trivalent elements most effectively, then divalent
transition metals, divalent Group IIA metals, and univalent
Group I metals. Plankton tend to accumulate in order of
decreasing affinity, Fe, Al, Ti, Cr, Si, Ga, Zn, Pb, Cu, Mn,
Co, Ni, Cd.20 Mollusks also concentrate trace metals very
effectively.21
All of these processes are highly dependent on ambient
conditions of temperature, turbidity, and flow patterns as
well as the chemical composition of the brines in question.
All that can be said given the present state of knowledge is
that, on the basis of sampling studies, measurable amounts
of trace metals discharged from oilfield operations find
their way into estuarine sediments. The major mechanisms of
this deposition can be identified; however, no reliable
information has been gathered to quantify either their abso-
lute rates or their relative importance.
. Stumm, Werner, and James J. Morgan, Aquatic Chemistry:
An Introduction Emphasizing Chemical Equilibria in Natural
Waters (New York: John Wiley & Sons, 1970).
18
Morgan, "Chemical and Geochemical Processes."
19
Morgan, "Chemical and Geochemical Processes."
20
Morgan, "Chemical and Geochemical Processes."
21
Energy Resources Co. Inc., A Review of Concentration
Techniques for Trace Chemicals in the Environment, for the
U.S. Environmental Protection Agency, EPA-560/7-75-002,
November 1975, pp. 452-455.
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C.2.3 Basic Sediment Transport Patterns
The ultimate distribution of sediments in estuaries
depends on their long-term sediment transport patterns.
These patterns result from the processes by which sediments
are introduced or resuspended into the water column, carried
by currents, winds, and tides, and deposited in more or less
stable configurations on the bottom. Several general obser-
vations, independent of the specifics of estuarine hydrology,
can be made regarding these processes:22
1. Resuspension occurs where mechanical or
biogenic reworking of sediments is appreciable
or where shear currents along the bed rise above a
critical value. Above this value, increasing bed
shear generally leads to increased resuspension.
2. Deposition occurs where bed shear is below a
critical value; below this value, decreased bed
shear generally leads to increased deposition.
3. The rate of sediment deposition is limited by
the rate of sediment formation, e.g., floccu-
lation, uptake of particulates by oil, etc.
4. Deposited sediments may flow to lower lying
adjacent areas.
5. Deposited sediments may be eroded under certain
flow conditions such as floods or spring tides.
In addition to these general considerations, the saline
wedge structure of estuaries has some very important effects
on the patterns of sediment transport and deposition.
Although the net flow of water in estuaries is from upriver
to downriver and then out into the open ocean, the greater
density of seawater and the periodic longitudinal movement
of saltwater/freshwater interface caused by tides often
gives rise to a net bottom flow upstream in the saline
portion of the wedge. At the bottom edge of the saline
intrusion this upstream flow is countered by the opposing
river flow, which tends to be lifted over the wedge as it
moves downstream. The saline wedge thus acts as a sort of
dam or weir, since net flow at its base is nearly zero as a
Ippen, "Sedimentation in Estuaries."
-342-
-------
result of opposing upstream and downstream flows. This region
of very small longitudinal flow is the nodal point of bed
shear.
Because sediment transport is most significant in the
bottom layers of water, sediments in the saline portion of
an estuary tend to travel upstream, whereas sediments sus-
pended in the river load tend to be carried downstream. At
the nodal point, some of the suspended sediments from both
the fresh and saline flows are lifted up from the bottom zone
and carried out toward the ocean; the remainder are deposited
at the node in shoals. As can be expected, the intensity
of this shoaling depends on the extent of the saline wedge
effect -- that is, on the extent of estuary stratification.
Highly stratified estuaries, such as the Southwest Pass
of the Mississippi River, are characterized by low tidal
ranges and a large influx of freshwater. Here, the shear
drag of seaward flowing freshwater on the relatively gently
sloping halocline pulls intruding saltwater toward the upper
layer of the wedge and seaward, drawing more saltwater land-
ward along the bottom of the wedge. The weir effect of the
nodal point is therefore enhanced, and shoaling tends to be
more pronounced. The special nature of highly stratified
estuaries, however, subjects this sediment transport pattern
to significant periodic variations. For example, the land-
ward flow of suspended sediments is weakest at low, falling
tides, and seaward flow dominates at all depths of the water
column during river flood conditions.23
In well-mixed, vertically homogenous estuaries, on the
other hand, the saltwater/freshwater interface is not so
well defined. Instead of vertical differentiation (a salt
wedge), the transition between saline and freshwater in this
type of estuary is more accurately described by a salinity
gradient upward in the direction of river flow. Hence, there
is not localized saltwater boundary, and the weir effect
characteristic of stratified estuaries is drastically reduced.
Shoaling in such cases will be dispersed, and such factors
as local topographical peculiarities and the Coriolis force
may play a more dominant if less predictable role in deter-
mining sediment distribution.
Of course, sediment transport patterns in any given
estuary may vary according to the locally prevailing condi-
tions of topography, major ocean currents, and sediment
O -3
Meade, "Transport and Deposition in Sediments in
Estuaries."
-343-
-------
characteristics. The Coriolis force also has a significant
effect on the movement of suspended sediments, depending on
the shape and width of the estuary. Despite these effects
which may vary from location to location, the dynamics of
saline intrusion play the largest role in determining trans-
port patterns in many estuaries. This role can be summarized
as follows.
1. Sediments settling on the bottom of an estuary
tend to be transported upstream.
2. Sediments tend to accumulate near the end of
the saltwater intrusion, forming shoals at the
nodal point of the bed shear.
3. The intensity of this shoaling is greatest
for stratified estuaries, least pronounced in
well-mixed estuaries.
C.3 Other Processes Affecting Marine Hydrocarbons
Oils and oil fractions will undergo a variety of
chemical, physical, and biological alteration processes
after their introduction into the marine environment, and
these can significantly affect the toxic properties of these
oils. The analysis of these effects is greatly complicated
by the fact that previous studies have dealt almost exclusively
with the crude oil slicks produced as a result of tanker
accidents, a situation which is of little relevance to the
dispersion or degradation of oilfield brines. Nevertheless,
some generally applicable conclusions do emerge from the
recent literature.
After their introduction into seawater, crude oil frac-
tions will begin to disperse, in a manner and at a rate
which will depend upon the physical properties of the oil
(viscosity, density, etc.) and on the magnitude of local
dispersion forces such as current or wind. As the oil dis-
perses, some of its more polar components will begin to
dissolve, and the ligher and more volatile hydrocarbons will
volatilize. Laboratory studies have suggested a strong
molecular weight dependence of the rate at which oil compo-
nents volatilize from seawater.24 The volatilization process
24
R.E. Kredier, "Identification of Oil Leads and Spills,"
in Proceedings of the Joint Conference on Prevention and
Control of Oil Spills (Washington, B.C.: American Petroleum
Institute, 1971), pp. 119-124.
-344-
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results in the loss to the atmosphere of the hydrocarbons.
According to a recent National Academy of Science (NAS)
report:
These evaporated hydrocarbons enter the atmospheric
pool of hydrocarbons, and very little is likely to
return to the oceans as hydrocarbons. Chemical
reactions in the atmosphere, such as phtotcatalytic
oxidations, convert an unknown amount of these
hydrocarbons into less volatile nonhydrocarbon
compounds that may re-enter the oceans. The fate -5
and effect of these types of compounds are unknown.
The sum of these two processes of solubilization and
volatilization is known as weathering, and the end result
is a weathered oil which is denser, more viscous, and
enriched in its content of high molecular weight hydrocarbons
relative to the original unweathered oil. The quantitative
literature on the weathering rates of oil under different
circumstances has dealt mostly with oil spill weathering,
and so has little relevance to the dilute, emulsified,
highly solubilized hydrocarbons which are contained in
oilfield brines. Another consideration to keep in mind is
the fact that these brines are generally higher in aromatic
hydrocarbon content than their parent crude oils, due to
the differential solubility of the various oil components in
the brine water (benzene, for example, has a saturation
solubility of about 1,800 ppm in distilled water, as com-
pared with about 10 ppm for the normal alkane of equivalent
molecular weight (hexane)). Since much of the toxic activity
of crude oil is concentrated in its aromatic fraction, the
toxicity of the brines is probably higher than would be
predicted from an equivalent dilution of ordinary crude oil.
Although volatilization may remove many of the more toxic
components from the brine, it will also enrich the brine in
a number of others, including the relatively heavy poly-
nuclear aromatics.
One of the most important processes involved in sca-
venging oil-derived hydrocarbons from the water column is
adsorption onto suspended particulates which are subsequently
deposited in bottom sediments as was discussed in the previous
section. Hydrocarbons can become entrapped in marine sediments
through a number of processes. These include ingestion by
zooplankton and the subsequent sedimentation of oil containing
25
National Academy of Sciences, Petroleum in the Marine
Environment, pp. 45-46.
-345-
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fecal material, adsorption onto suspended mineral particles
which subsequently settle out, and direct adsorption onto
bottom silt and clay. The chief effect of the adsorption
process is probably to decrease the effect of the hydrocarbons
on organisms other than benthic organisms and filter feeders.
The effect on these two groups will probably be greatly
increased because of the tremendous concentration factor
which is associated with adsorption onto particulates. In
fact, it has been noted that areas which have significant
concentrations of oil in their sediments usually have "an
impoverished benthic fauna,"26 although the causal relation-
ship has not been clearly demonstrated.
Although adsorption onto particles seems to facilitate
biological and chemical oxidative degradation of hydro-
carbons, particle-adsorbed hydrocarbons which settle into
sediment seem remarkably stable, probably because of the
anaerobic conditions prevailing within the sediment. Sedi-
ment-entrapped hydrocarbons also seem to be unusually
resistant to photochemical degradation, except at the very
top of the sediment layer. According to Blumer and Sass,
"The preservation of hydrocarbons in marine sediments for
geologically long time periods is one of the accepted key
facts in current thought on petroleum formation."27 Experi-
mental studies of oil-contaminated sand columns have suggested
that although 10 percent of the trapped oil oxidized over a
period of several months, the remainder deteriorated at a
much slower rate.28 Solubilization of hydrocarbons from
sediment, and the ingestion of sediment particles by benthic
organisms, provide processes whereby the transfer of hydro-
carbons from water to sediment may be reversed.
In addition to these essentially physical alterations,
crude oil in seawater is subject to a number of chemical
degradation processes. Chiefly, these are oxidative pro-
cesses (auto-oxidative and photo-oxidative) which change the
U.S. Environmental Protection Agency, Water Quality
Criteria, 1972.
27
Blumer and Sass, "Oil Pollution: Persistence and
Degradation of Spilled Oil," Science 176 (1970): 1120-1122.
2 g
Evans and Rice, "Effects of Oil on Marine Ecosystems:
A Review for Administrators and Policy Makers," Fishery
Bulletin 72 (1974): 625.
-346-
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relatively reduced aromatic and aliphatic hydrocarbons
species found in crude oil into more oxidized acids, alde-
hydes, and alcohols. Light acts as an important inducer of
oxidation through the formation of free radical intermediates
and hydroperoxides. (Photo-chemically induced free radical
intermediates can also polymerize. The end product of the
polymerization reaction is dense, viscous, relatively polar
"tar.") Oxidation will be accelerated by physical factors
which tend to disperse or emulsify the oil, and by metallic
catalysts, and many sulfur compounds are strong inhibitors
of oxidation. A priori chemical arguments support some
general conclusions regarding the relative rates at which
different oil-derived hydrocarbons will oxidize in the
marine environment.29
Another important class of processes which alter oil in
seawater is biodegradation; indeed, it is probably the chief
pathway by which polluting oils are removed from the marine
environment. According to Atlas and Bartha:
Microbial degradation of crude oil appears to be
the natural process by which the bulk of the polluting
oil is eliminated and may be the reason that the oceans
are not entirely covered with oil today. Under fa-
vorable conditions microorganisms are quite effective
in degrading low levels of petroleum. In areas that
are well aerated and where the microbial population is
adapted to oil influx, the rate of oil oxidation at
20° C to 30° C may range from 0.02 g to 2.0 g of oil
oxidized/m^/day.... Microorganisms will degrade a
substantial portion (40 percent to 80 percent) of crude
oil, but the degradation is never complete; n-alkanes
are utilized preferentially and highly branched alkanes,
cycloalkanes, and aromatics are utilized with difficulty;
and mixed enrichments are more effective in petroleum
degradation than mixed cultures.30
Although much laboratory and field data are now available
on the microbiological degradation of crude oils and oil
components, it remains impossible to make any reliable quan-
titative estimates of the rate at which this process will
remove oil from oilfield brines. According to the NAS:
29
Atlas and Bartha, "Fate and Effects of Polluting Petro-
leum in the Marine Environment," Residue Review (1973c) : 49-85.
Atlas and Bartha, "Fate and Effects of Polluting Petro-
leum in the Marine Environment."
-347-
-------
Neither a single rate nor a mathematical model for
the rate of petroleum biodegradation in the marine
environment can be given at present. On the basis of
available information, the most that can be stated is
that some microorganisms capable of oxidizing chemicals
present in petroleum (under the right conditions) have
been found in virtually all parts of the marine envi-
ronment examined.31
Nevertheless, a number of factors can be isolated as
being important in controlling the rate of oil degradation.
The composition of the available substrate is critical,
since mircoorganisms are limited in the range of hydro-
carbons they can oxidize. Pure cultures rarely degrade more
than one hydrocarbon fraction. Mixed cultures isolated from
the marine environment possess wider degradative capacities,
although preference for intermediate length n-paraffins is
usually observed. It is uncertain whether this pattern is
a result of the isolation procedure used; certain wild,
mixed cultures developed in media containing cyclic hydro-
carbons, notably napthalenes and polynuclear aromatics, have
been found to degrade such compounds more rapidly than n-
paraffins.32
Hydrocarbon-oxidizing microorganisms are widely distri-
buted in soil and water. Relatively few hydrocarbonoclastic
microbes are found in soils or areas of the open ocean
remote from oilfields or oil pollution; they are most
numerous and diverse in places that have been subjected to
chronic oil pollution either from natural seeps or by the
activities of man. Hydrocarbon-degrading microorganisms are
only rarely found in petroleum as it emerges from oil wells
or in unpolluted ground waters. One preliminary indication
based on laboratory experimentation is that the abundance
and physiological types of hydrocarbon-oxidizing microbes in
soil and aquatic environments seem to be influenced by the
quantities and kinds of hydrocarbons which have been present
National Academy of Sciences, Petroleum in the Marine
Environment, pp. 45-46.
32
C.E. Zobell, "Microbial Degradation of Oil: Present
Status, Problems, and Perspectives," in The Microbial Degra-
dation of Oil Pollutants, ed. by D.G. Ahearn and S.P. Meyers
(Baton Rouge: Louisiana State University, Center for Wetland
Resources, 1973), p. 5.
Zobell, "Microbial Degradation of Oil," p. 3.
-348-
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Environmental conditions can significantly affect
microbial hydrocarbon degradation. Temperature and salinity
changes, wave action, and sunlight can alter the physical
state (emulsification) and ultimately the chemical nature
(oxidation) of the hydrocarbons. Oil dispersed in aqueous
systems is more suceptible to enzymatic attack; dispersion
is influenced by viscosity, density, chemical composition,
wind speed, current velocity, and temperature. Some micro-
bial species produce surfactants which tend to emulsity oil
in water.34
The growth and metabolism of the microorganisms them-
selves are intimately related to environmental parameters.
Free or dissolved oxygen is essential, as is the presence of
accessory growth factors such as nitrogen and phosphorous.
Temperature can exert a profound influence upon growth and
metabolic activity of microbial species. In general, tem-
perature increases accelerate growth rates, while low
temperatures reduce the rates of biological processes. The
microbial degradation of oil has been observed at tempera-
tures ranging from the freezing point of seawater (around
-2° C) to about 70° C. Most species are most active in the
mesothermic range, 20° C to 35° C.
Deleterious environmental influences upon hydrocarbono-
clastic microbes are microbial predators and toxic substances.
Cytophagic protozoans and other invertebrates can ingest
large numbers of microbes. Toxic components of oil include
the 'low molecular weight hydrocarbons and the metal ions
frequently associated with petroleum. It is thought that
low molecular weight hydrocarbons disrupt functional phos-
pholipids of the cell envelope, 35 ancj that heavy metals .,,
decrease the efficiency of the microbial transport system.
It is apparent from the above discussion that the number
of factors influencing microbial hydrocarbon degradation is
34
Zobell, "Microbial Degradation of Oil," p. 6.
O.K. Button, "Petroleum — Biological Effects in the
Marine Environment," in Impingement of Man on the Ocean, ed.
by Donald H. Wood (New York: Wiley-Interscience, 1971),
Chapter 14.
P.J. Kinney et al., Quantitative Assessment of Oil
Pollution Problems in Alaska's Cook Inlet (College, Alaska:
University of Alaska, 1970), p. 9.
-349-
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vast. Consideration of the various parameters must be made
from one location to another as well as within the context
of a given site. The limited number of reliable and compre-
hensive fluid measurements poses a barrier to large-scale
generalizations; what information that exists for Barataria
Bay and Cook Inlet is discussed briefly below.
Barataria Bay
According to Meyers and his associates:
The vast productivity of wetland regions along the
Louisiana coast, and their proximity to oil-producing
sites, necessitates a more comprehensive understanding
of the significance of alterations in the microbial
community concurrent with oil intrusion and massive
depositions of petroleum effluents.37
Unfortunately, few studies have been conducted on the effects
of oil pollutants on inshore plant-dominated communities and
their complex microbial ecosystems. Meyers and his associates
have noted exposure of marsh areas of Barataria Bay to
controlled additions of oil significantly alters the compo-
sition of the yeast community. Shifts toward an asexual
hydrocarbonoclastic yeast flora have been documented. The
impact of oil deposition upon major microbial components of
the marshland ecosystem has only recently received attention;
studies on the marine bacteria Benecka have indicated an
ability to readily metabolize a wide range of organic compounds,
including aromatic and aliphatic hydrocarbons.38
Cook Inlet
Average concentrations of 10 hydrocarbon-utilizing
microorganisms per liter have been reported for Cook Inlet.
According to Kinney and associates, "Biodegradation is more
important than physical flushing in removing hydrocarbon
37
S.P. Meyers et al., "The Impacts of Oil on Marshland
Microbial Ecosystems," in The Microbial Degradation of Oil
Pollutants (Baton Rouge: Louisiana State University, Center
for Wetland Resources, 1973), p. 221.
38
Meyers et al., "The Impact of Oil on Marshland Micro-
bioal Ecosystems," p. 225.
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pollutants from Cook Inlet...the biodegradative capacity of
Cook Inlet is large."39
The low temperature and high silt content of Alaskan
waters have been examined as potential inhibitors of oil
biodegradation. It appears that silt does not interfere
significantly with the emulsification properties of hydro-
carbonoclastic microbes. The extremely cold water lowers
growth rates, so that nutrient concentrations are probably
non-limiting. Growth rates of isolated microbes grown on
kerosene as a sole carbon source were reduced by a factor
of seven at 50° C, the prevailing summer temperature of
Cook Inlet.40 Psychrophilic (i.e., low-temperature adapted)
oil-oxidizing bacteria from Cook Inlet have been reported
active at 5° C; bacteria from northern Alaska have been
shown to oxidize mineral oil at -1° C.41 In addition to
depression of metabolism', low temperatures interface with
the dispersal of oil by entrapment in ice.
In both Barataria Bay and Cook Inlet, it is unknown
whether the composition of produced petroleum waters has any
special impact on microbial biodegradation. Heavy metal ion
concentrations may be inhibitory. The effect of putative
aromatic enrichment of produced waters cannot be properly
assessed until water composition and aromatic-oxidizing
potentials of hydrocarbonoclastic microbes are determined.
Further characterization of these parameters is critical for
meaningful impact assessment.
C.4 Other Processes Acting on Trace Metals in the Marine
Environment
Three processes, in addition to precipitation, adsorp-
tion and sedimentation (discussed in Section C.2) are im-
portant in altering and modifying the toxicity of heavy
metals in the marine environment. Their effect on toxicity
is discussed more completely in Chapter Six, so they will
only be briefly mentioned here. The first is chelation and
39
Kinney et al., Quantitative Assessment of Oil Pollution
Problems in Alaska's Cook Inlet, p. 1, 9.
40
Kinney et al., Quantitative Assessment of Oil Pollution
Problems in Alaska's Cook Inlet, p. 1, 9.
41Zobell, "Microbial Degradation of Oil," p. 153.
-351-
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other forms of chemical complexation with organic materials
in water. The second is biological transformation, including,
most notably, the microbiological methylation of mercury;
and the third is oxidation. This last process is especially
significant since the oxidized forms of many metals (e.g. Cr
(VI)) can be much more toxic than the equivalent reduced
species (Cr (III)). As with hydrocarbons, not enough quanti-
tative field or laboratory data is available to enable
reliable predictions of the rates at which these processes
will occur in the marine environment, or the extent to which
they will affect toxicity.
-352-
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APPENDIX D
PRODUCTION PLATFORM AND DISCHARGE DATA
The Bay de Chene oil field located in Hackberry Bay,
Louisiana, adjacent to Barataria Bay, is operated by Texaco.
The Salt Water Disposal Well Report for calendar year 1975
filed with the Louisiana Department of Conservation, Geologi-
cal Oil and Gas Division, Baton Rouge, Louisiana, gives a
figure of 22,374,127 barrels produced salt water (i.e., an
average rate of 61,000 barrels per day).
Table D-l lists the sources of produced water in Cook
Inlet, Alaska. The two facilities chosen for analysis in
this study were the Granite Point Production Facility
operated by Atlantic Richfield Company, and the Trading
Bay Production Facility, operated by Marathon Company.
Block 16 of the Grand Isle Oil Field Area is operated
by Exxon Co. Produced water data filed with the Houma office
of the Louisiana Department of Conservation gives a 1975
figure of 3,231,300 barrels produced water (i.e., an average
discharge rate of 9,000 barrels per day).
Block 108 of the Ship Shoal Oil Field Area is operated
by Chevron Company. Produced water disposal data filed with
the U.S. Geological Survey in Metairie, Louisiana lists two
platforms disposing produced water, S-93 with an average rate
of 9,000 barrels per day, and S-94 with an average rate of
12,000 barrels per day.
-353-
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TABLE D-l
SALT WATER DISPOSAL - COOK INLET, ALASKA
OFFSHORE
PLATFORMS3
Bruce
Granite Point
Anna
Granite Point
Dillon
Middle East
Ground Shoal
ONSHORE
FACILITIES
Granite Point
Production
LOCATION
60°59'
151°17'
60°58'
151°18'
60°44'
151°30'
56"
52"
37"
45"
08"
45"
LOCATION
151°25'
14"
DISCHARGE
(bbl/d)
N 493
W
N 41
W
N 5,231
W
DISCHARGE
(bbl/d)
N 5,000
W
OPERATOR
Amoco
Amoco
Amoco
OPERATOR
Atlantic
Richfield
Facility13
Trading Bay
Production
Facility0
Kenai -,
Gas Field
North of East
Foreland Pro-
duction Facility
60°49'05" N
151°46'59" W
60023'53" N
151016'36" W
60°44'13" N
151"21'05" W
12,500
262
3,809
Marathon
Union
Shell
NOTE: Footnotes are on the following page.
-354-
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FOOTNOTES TO TABLE D-l
aData were obtained from Danfofth G. Bodien, Chief,
Water Permits Section, U.S. Environmental Protection Agency,
Seattle, Washington. Data are for 1975.
Atlantic Richfield Company, U.S. Army Corps of Engi-
neers, "Application for Permit to Discharge or Work in
Navigable Waters and Their Tributaries," AK-NPD-NPS-2-00019,
1971.
°Marathon Oil Company, U.S. Army Corps of Engineers,
"Application for Permit to Discharge or Work in Navigable
Waters and Their Tributaries," AK-NPA-NPA-2-000148, 1971.
Union Oil Company of California, "National Pollutant
Discharge Elimination System Application for Permit to
Discharge," AD-002455-4, 1974.
(^
Shell Oil Company, U.S. Army Corps of Engineers,
"Application for Permit to Discharge or Work in Navigable
Waters and Their Tributaries," AK-NPD-NPA-2-000047, 1971.
-355-
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APPENDIX E
CALCULATION OF DISPERSION MODEL INPUT PARAMETER VALUES
E.1 Estimate of Tidal and Freshwater Current Velocities
for Hackberry Bay, Louisiana
In the absence of actual current measurements it is
necessary to estimate current magnitudes. Relatively simple
hydrological calculations will suffice for the purpose of
supplying input parameter values for the dispersion model.
To estimate the tidal velocity, the estuary is assumed to be
represented by a channel as in Figure E-l. The end at y=0
is assumed to be closed, the width at a distance y=y' along
the channel is given by W(y'), and the area enclosed by the
channel boundaries between y=0 and y=y' is given by K(y').
Thus
fY'
K(y') = / W(y)dy.
•^ n
The depth H is a function of both location, y, and of * time,
t, since it varies with the tidal influx and ebb. It is
further assumed that (1) there is no vertical variation in
the velocity of water in the y-direction, V(y,t), and that
(2) the tidal level rises and falls simultaneously at the
same rate for all points in the estuary channel. A simple
consideration of the relation of the volume of water in the
estuary in the portion which lies between y=0 and y=y' to
the influx or ebb of water through a vertical cross section
at y=y' then gives the equation:
K(y') 7 = -V(y',t)W(y')H(y')
Solving for V gives the equation:
9H(y',t)
v, , fc) _ K(y') 9t
^y ' " W(y') H(y',t)
-357-
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The depth of water, H(y',t) can be expressed as a sum of two
components: (1) a mean depth, Ho(y'), which is time
independent, and (2) a sinusoidally varying component,
(A/2) sin[ (2TT/T) t] , where A is the tidal range (i.e., the dif-
ference between low tide and high tide) and T is the tidal period,
Thus
H(y',t) = HQ(y') + -J- sin(^- t) ,
3H(y',t) = _jr . e,2ir_
_
3t T — t) ,
and,
3H(y',t)
3t
. ,2TT
H(y',t) H(y')+-- sin(r- t)
The maximum value of this ratio is
T H0(y')
so that the maximum current speed is given by:
• v K(y') _TT_ A
max (y ' W(y') T HQ (y' )
F-or Hackberry Bay, considering a cross section at the
lower end of the bay:
K = 4,386 acres = 19,105 x 104 ft2
W = 2 miles
T = 24 hours (diurnal tides)
so that,
-358-
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4- = 0.658 ft/sec
Thus,
Vmax =0.658-|- ft/sec
For A = 1 ft, H =2.4+0.5=2.9 ft
and,
V = 0.658 x —^Q- = 0.22 ft/sec
lUclX £. • _7
For A = 0.25 ft, HQ = 2.4 + 0.125 = 2.5 ft
and,
V = 0.065 ft/sec
max
Given the value of Vmax the tidal velocity is then given bv
Vmax sin [ (27r/T)t].
To estimate the freshwater current speed, reference is
made to a tabulation-'- of the flood and ebb flow volumes
through the four major passes to Barataria and Caminada
Bays. This table is reproduced in Appendix A as Table A-9.
The total ebb excess through the four passes is 449 x 10^ ft
If this is taken to be a measure of the freshwater influx to
the Barataria and Caminada Bay basin each day, then the
freshwater influx in ft3 per second in 5,197 ft^/sec. It
may be assumed that this freshwater flow must come from the
north through Hackberry Bay and adjacent bay areas. Assume
further that the freshwater flow is uniformly distributed
B. Barrett, Cooperative Gulf of Mexico Estuarine Inven
tory and Study, Louisiana, Phase II: Hydrology (New Orleans;
Louisiana Wildlife and Fisheries Commission, 1971), p. 57.
-359-
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through a vertical cross section through Hackberry Bay and
the adjacent bay areas. The width of this cross section is
approximately 11.8 miles (3 inches on a 1:250,000 scale
map). Hackberry Bay itself has a width of about 2 miles.
Hence the freshwater flow through Hackberry Bay can be
estimated to be:
x 5,197 ft3/sec.
Let V0 be the freshwater current speed in ft/sec. Then the
product of Vo and the area of a vertical cross section
through Hackberry Bay must be equal to freshwater flow
through Hackberry Bay. Thus, taking the average depth of
Hackberry Bay equal to 2.4 feet,
V x (2 x 5,280 x 2.4) = ^-Q x 5,197
O J-J- . o
or,
V = 0.035 ft/sec
E.2 Calculation of Tidally Averaged Diffusion Coefficient
for Cook Inlet
The procedure used for incorporating the effects of the
Cook Inlet tidal currents into the alongshore diffusion
coefficient, Ey, is as follows. First the steady downstream
freshwater flow, Vo, was estimated starting with .the stream
flow data for mid and upper Cook Inlet given in Appendix A,
Table A-3. Since stream flow data is available only for
some of the sources feeding into Cook Inlet, an estimate of
the total freshwater influx was obtained by dividing the sum
of the known mean daily discharges (62,234 ft-vsec) bY tne
sum of the corresponding drainage areas (24,847 square
miles) to give an average ratio of 2.5 ft3/sec freshwater
discharge per square mile of drainage area. Multiplied by
the total drainage area of 46,927 square miles, this gives
an estimated mean daily freshwater runoff rate of 117,500
ft-Vsec. The vertical cross section area of mid Cook Inlet
in the vicinity of the oil fields was estimated by computing
the area enclosed by the depth profile curve given in
Appendix A, Figure A-3 to be 8,120,000 square feet. Assuming
that the freshwater flow is equally distributed over this
vertical cross section (a reasonable assumption in view of
-360-
-------
the expected vigorous mixing resulting from the rapid tidal
currents), the ratio of the estimated freshwater discharge
rate to the cross section area gives an estimated downstream
freshwater flow speed of 0.014 ft/sec.
The analytical solution for the steady-state distri-
bution of a conservative substance discharged into a uniform
estuary at y=0 is:2
V
C(y) = C(0)e ~g^ y
y
where y is the distance upstream from the discharge point
and Ey is the diffusion coefficient. The diffusion coeffi-
cient can be estimated if it is assumed that at a distance
of one tidal excursion, yT, (the distance that a particle
can be moved upstream by the tidal currents during half a
tidal cycle) the concentration will have decreased approxi-
mately to e~^ (=0.37) times its value at the discharge
location. Then,
V_o
E ^T
y
and,
E = V v
y o T
Since the mean upstream tidal velocity is approximately 4
ft/sec in mid Cook Inlet,
yT = 4 x (6 hrs x 3,600 ) = 86,400 ft.
Using this value for yT and the value of 0.014 ft/sec for V
gives an estimated value for E of
E = 1,250 ft2/sec.
2.
Tracor, Inc., "Estuarine Modeling: An Assessment,"
February 1971, NTIS No. PB-206807.
-361-
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This value is not far removed from the value of 4700 ft /sec
obtained for Ey in a study-^ of discharges into an arm of Cook
Inlet, Knik Arm.
E.3 Computation of Diffusion Coefficients for Hackberry Bay,
Louisiana
The computation of the values of the diffusion coeffi-
cients, Ex and Ey, for Hackberry Bay, Louisiana, is based on
the theory of diffusion in turbulent shear flows.
The general form for the diffusion coefficient in a
shear flow is:
•p = fy H H
where,
E = diffusion coefficient
a = dimensionless coefficient
u* = friction velocity
H = water depth
The friction velocity, u* is further related to the bottom
shear stress by the relationship:
To = pu*
R. Sage Murphy, et al., Effect of Waste Discharges into
a Salt Laden Estuary. A Case Study of Cook Inlet, Alaska,
Publication IWR 26 of the Institute of Water Resources,
University of Alaska, Fairbanks, Alaska, November 1972.
-362-
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where,
T = bottom shear stress
o
p = water density
The relationship between u* (or TO) and the mean current
velocity, U, is always an empirical one. The most general
correlation is the following:
f r-,2
To = 8 PU
where f is a dimensionless friction factor that is a function
of the roughness of the bottom. With this formulation one
obtains:
U
Values of f for natural channels range from 0.01 to 0.1
resulting in a range of u*/U values of from 0.035 to 0.110.
Another often used correlation is the Mannings formula
which is equivalent to the following equality:
- 3.8
where n is a coefficient that varies from 0.020 to 0.040 for
natural channels. Thus for channels from 1 to 10 feet
deep, the resulting u*/U ratio varies from 0.050 to 0.140, a
slightly higher range than indicated by the values of the
friction factor.
For the purposes of further discussion, the value of
uA/U will be based on a value of n = 0.035 which is commonly
used for natural channels. Assuming a water depth of 3 feet
yields:
-363-
-------
- • o-1
The value of the dimensionless coefficient, a, will
depend on the type of mixing being parameterized by the
coefficient, E. The following table summarizes results
given in a review paper by Fischer:4
Type of Mixing Range of a
Transverse diffusion
1-D Flows (Channels) 0.1 - 0.7
2-D Flows (Bays) 1-2.4
Longitudinal Diffusion
1-D Flows (Channels)
5 - 400
2-D Flows (Bays)
The above results can now be applied to Hackberry Bay.
The water depth is
H = 3 feet
and mean velocity approximately,
U = 0.25 ft/sec
Using the values of a in the above table, and a value of
U/U = 0.1 the following values of E are obtained:
4
H. Fischer, "Longitudinal Dispersion and Turbulent
Mixing in Open-Channel Flow," Annual Review of Fluid Mechanics
Volume V, ed. by Van Dyke (Palo Alto, Calif: Annual Reviews,
Inc., 1972).
-364-
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Type of Mixing
Range of E
Base Values Used
In Analysis
Transverse Diffusion
1-D Flow
0.0075-0.053 ft /sec
= 0.1
2-D Flow
Longitudinal
Diffusion
0.075-0.18 ft /sec
0.375-30 ft /sec
Ey = 1.0
E.4 Calculation of Initial Dilution for Gulf of Mexico
Computations
Produced water is generally more saline and hence more
dense than sea water. Accordingly, the discharged effluent
tends to sink through the receiving waters and to form a
layer at the bottom of the water column. In the course of
sinking, sea water becomes mixed with the discharged effluent.
The resulting dilution can be estimated using methods developed
for thermal plume prediction,5 since the dilution of heated
water as it rises through cooler receiving waters is completely
analogous to the sinking plume situation encountered in brine
discharge.
To estimate the initial dilution, it is first necessary
to calculate the Froude number, F, defined as:
U
o
V
Ap
where,
U = effluent discharge velocity
M.S. Shirazi and L.R. Davis, Workbook of Thermal Plume
Prediction, Volume 1: Submerged Discharge, EPA-R2-72-005a
(Corvallis, Oregon: National Environmental Research Center,
U.S. Environmental Protection Agency, August 1972).
-365-
-------
= gravitational acceleration
= diameter of discharge pipe
= density of receiving water
Ap = difference in density of effluent and receiving
water
Assuming a discharge pipe diameter of one foot and a rate of
effluent discharge of 1 ft^/sec, Uo = 1.27 ft/sec. The
density of water as a function of salinity has been tabu-
lated by the U.S. Navy Hydraulics Office, and salinity can ,
be related to the chloride ion concentration by the relation:
S(ppt) = 1.80655 Cl~ (ppt)
Using the value of 61 ppt Cl in Louisiana produced water
and the value of 19 ppt Cl in sea water gives
S . =34.3 ppt
sea water ^c
produced water = 110>1 ppt
The above-mentioned density-salinity tabulation then gives
(using linear extrapolation to obtain the density corres-
ponding to the produced water salinity):
P . 1.0228
sea water
produced water
A. Duxbury, The Earth and Its Oceans (Reading, Mass.:
Addison-Wesley Publishing Co.), p. 116.
-366-
-------
Hence,
F = LilZ = o.95
v.
1.0797 - 1.0228
1.0228
For a conservative estimate of dilution, assume that
the effluent is discharged vertically downward. Then the
chart on p. 81 of the EPA Workbook (reproduced as Figure E-2)
can be used together with the value of the Froude number,
F = 1, and data on the total water depth to estimate the
initial dilution. The normalized vertical distance Z/D
plotted on the horizontal axis in Figure E-2 is, in our
notation, the water depth H divided by the diameter of the
discharge pipe, d (more accurately, Z/D is equivalent to
(H - H2)/d where H2 is the thickness of the layer formed by
the effluent at the bottom of the water column; H2 - H/6).
The vertical axis of Figure E-2 is, in our notation, 1/D,
where D is the initial dilution. Thus, for example, using a
value of H = 33 feet, and a value of d = 1 foot, the nor-
malized vertical distance is [33-(33/6)]/l = 27.5. Reading
upwards from 27.5 on the horizontal axis of Figure E-2 until
the F = 1 curve is reached, and then reading across to the
vertical axis gives a value of 1/D = 0.04 or D = 25.
-367-
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1.0
I
CO
CTi
CD
I
0.1
s
ui
a.
Z
X.
-j
a:
0.01
20 27.5 40
RNN
TEMPERATURE/WIDTH CHART
6 • 90"
60 80 100
VERTICAL DISTANCE Z/0
120
140
160
180
200
Figure E-2. Temperature-width chart for single jets discharging
into a non-stratified stagnant large body of water: RNN, 9=90°.
(U.S. Environmental Protection Agency, Workbook of Thermal Plume Pre-
diction, Volume 1; Submerged Discharge, August 1972, p. 81.)
-------
APPENDIX F
HYDROCARBON BIOACCUMULATION
Many marine organisms have the capacity to take up and
accumulate hydrocarbons from their environments. This has
been demonstrated in mussels, clams, oysters, crabs, shrimp,
sponge and fish, among others. Both field and laboratory
studies have dealt with the accumulation problem. Although
the results of these studies are varied and often inconsis-
tent, they do succeed in demonstrating that the ability to
accumulate hydrocarbons is widespread among marine organisms.
In this section the general nature of hydrocarbon uptake,
metabolism, storage and discharge will be discussed, and
summaries of the current understanding of accumulation
capabilities of various organisms will then be presented.
Uptake of petroleum hydrocarbons from seawater can be
accomplished by four means:
1. Ingestion of particles onto which hydrocarbons
have been adsorbed. These particles can be either
biotic (e.g., plankton) or non-biotic (e.g.,
sand.
2. Adsorption onto exposed body surfaces.
3. Active uptake of dissolved or dispersed
petroleum, as in the gills of bivalves.
4. Intake of water into the gut of organisms that
drink or gulp water.
Entry through the gill membranes of dissolved or dispersed
oil occurs widely in molluscs, crustaceans, and fish. Many
marine animals ingest contaminated food, sediment particles,
or water. To date there has been no conclusive demonstration
of food web magnification of petroleum hydrocarbons.
Once hydrocarbons have been taken up by an organism,
they can be stored and accumulated, metabolized, or dis-
charged. In general, storage takes place in the hepato-
pancreas of invertebrates, and in the liver of fish. There
are many other sites of accumulation, however, as will be
discussed below.
-369-
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Marine fish and some marine invertebrates can metabo-
lize both paraffinic and aromatic hydrocarbons.1 Some
copepods can metabolize paraffins, but not aromatics.
Organisms such as phytoplankton, zooplankton, and many
marine invertebrates appear to be unable to metabolize any
hydrocarbons. Petroleum metabolism occurs in the liver of
fish and in the hepatopancreas of invertebrates.
Most marine organisms which have accumulated signifi-
cant internal concentrations of petroleum hydrocarbons have
been found able to release much of the contamination upon
transfer to clean, unpolluted water. Blumer^ reported long
term retention of hydrocarbons by shellfish, but his results
have not been reproduced in subsequent studies. As will be
shown below, tissue contamination, if not lethal, can gener-
ally be discharged when the source of pollution is removed.
Clark and Finley studied accumulation by sea urchins
and crabs exposed to Navy Special Fuel Oil following the
grounding of a Navy vessel on the coast of Washington.
Purple sea urchins accumulated 2.4 ppm dry weight of n-
parrafins; the crabs (Hemigrapsus nudus) contained 1.2 ppm.
These animals were exposed to a continuous low level of
contamination, since oil leaked continuously from the
wrecked ship for a long period of time.
Richard F. Lee and A.A. Benson, "Fate of Petroleum
in the Sea: Biological Aspects," in Background Papers for
a Workshop on Inputs, Fates, and Effects of Petroleum in
the Marine Environment (Washington, D.C.: National Academy
of Sciences, 1973) .
M. Blumer, S. Souza, and J. Sass, "Hydrocarbon Pollu-
tion of Edible Shellfish by an Oil Spill," Marine Biology 5
(1970): 195-202.
Robert C. Clark, Jr. and John S. Finley, "Long-Term
Chemical and Biological Effects of Persistent Oil Spill
Following the Grounding of the General M.C. Meigs," in
Proceedings of the 1975 Conference on Prevention and Control
of Oil Pollution, American Petroleum Institute, U.S. Environ-
mental Protection Agency, 1975.
-370-
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Hydrocarbon accumulation in shrimp has been studied by
a number of investigators, since shrimp are an important
commercial product, and are consumed directly by humans.
Grass shrimp (Palaemonetes pugio) exposed to 0.07 ppm naph-
thalenes in an oil-water dispersion accumulated up to 3 ppm .
wet weight of naphthalenes during a 12-hour exposure period.
Upon transfer to clean water the shrimp discharged the
hydrocarbons readily. Tissue hydrocarbon levels were normal
after 14 to 38 hours of depuration. Brown shrimp exposed to
0.3 ppm No. 2 fuel oil for 20 hours accumulated up to 800 ppm
of naphthalenes in the digestive gland. After one hour
of depuration the abdominal muscle tissue — the part
consumed by humans — had returned to the normal background
hydrocarbon level. Hydrocarbons were retained in the diges-
tive gland and the gills after 250 hours depuration. This
is due to the much greater accumulation in the digestive
gland. The gills, a site of hydrocarbon uptake and release,
can be expected to retain high concentrations for a longer
period of time than other tissues.
Mussels are often used for contamination experiments
for a number of reasons. They are widespread and readily
available. They are a convenient size — small enough to
sample adequately but large enough to dissect for specific
organ analysis. They are a major energy transfer pathway in
intertidal ecosystems, utilizing plankton and debris as food
sources. Finally, they have a well known capacity to accumu-
late pollutants. Clark and Finley5 maintained mussels
(Mytilus edulis) beneath an experimental No. 2 fuel oil
slick for 48 hours, and observed body concentrations of
29 ppm dry weight. The n-paraffin residual pattern (the n-
paraffin composition of the exposed animal minus the normal
n-paraffin composition) was similar to the fuel composition,
indicating non-selective uptake of hydrocarbons. Most of
the accumulated paraffins were released when the mussels
were transferred to clean water, although a certain residual
remained.
4
Jack W. Anderson, ed., Laboratory Studies on the
Effects of Oil on Marine Organisms; An Overview, American
Petroleum Institute Publication #4249, 1975.
R.C. Clark, Jr. and J.S. Finley, "Uptake and Loss of
Petroleum Hydrocarbons by the Mussel, Mytilus edulis, in
Laboratory Experiments," Fishery Bulletin 73 (1975): SOS-
SIS.
-371-
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Lee et al. examined distribution of hydrocarbons in
different tissues of M. edulis after exposure to heptadecane
and to naphthalene for 24 hours. Twenty-four hour exposure
to 6.2 ppm heptadecane resulted in the following tissue
concentrations: (ppt dry weight) Whole 6.0, Gill - 13.0,
Mantle - 7.8, Adductor muscle - 1.4, and Gut - 20.0.
Results were similar for a four hour exposure to 32 ppm
naphthalene: (ppt dry weight) Whole - 7.0, Gill - 9.0,
Mantle - 2.0, Adductor muscle - 6.0, and Gut -7.0. Over
90 percent of the accumulated hydrocarbons were discharged
after transfer to clean water. No evidence was found for
hydrocarbon metabolism.
Fossato transferred mussels (Mytilus galloprovincialis)
from an environment polluted with diesel fuels, gasoline,
and lubricating oils to an unpolluted environment and mon-
itored depuration. In the first 10 to 15 days the concen-
tration dropped exponentially to about 12 percent of its
initial value. Thereafter the decrease was extremely slow.
Within the range 7.5° C to 26.0° C the rate of depuration
appeared to be temperature independent.
Mytilus californianus transferred from clean water to
a polluted area of the San Francisco Bay accumulated 325 ppm
dry weight hydrocarbons in three months.8 Five weeks after
the mussels had been transferred back to the unpolluted
water they had released 90 percent of the hydrocarbons to
the environment. However, M. edulis that had grown up in
the polluted area experienced only minor losses of contami-
nants during a 10-week period in clean water. Eggs from
unpolluted organisms of the same species accumulated 332 ppm
dry weight of hydrocarbons during a 10-week exposure to
polluted water. Seventy-six percent of the contamination
was composed of aromatics. Results of this study indicate
that mussels transferred from clean to polluted water and
Richard F. Lee, Richard Sauerheber and A.A. Benson,
"Petroleum Hydrocarbons: Uptake and Discharge by the Marine
Mussel Mytilus edulis," Science 177 (1972) : 344-346.
Valentino U. Fossato, "Elimination of Hydrocarbons by
Mussels," Marine Pollution Bulletin 6 (1975): 7-10.
Q
Louis H. Disalvo, Harold E. Guard, and Leon Hunter,
"Tissue Hydrocarbon Burden of Mussels as Potential Monitor
of Environmental Hydrocarbon Insult," Environmental Science
and Technology 9 (1975): 247-251.
-372-
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back readily discharged accumulated petroleum, whereas
mussels originally taken from the polluted waters retained
much of their hydrocarbon body burden even in clear water.
This may suggest the existence of two types of accumulation:
short-term accumulation in which take-up and release are
rapid, and long-term or chronic accumulation where the
concentration is built up over an extended period of time
and is not readily discharged.
The American oyster, Crassostrea virginica, has also
been the subject of much study. J. Anderson^ exposed oysters
to 1 percent oil-water dispersions of four oils for four
days with the following resultant tissue concentrations of
hydrocarbons: No. 2 fuel oil - 96.7 ppm net weight; Bunker
C oil - 47.4 ppm; South Louisiana crude - 65.8 ppm; and
Kuwait crude - 107.1 ppm. These results agree with results
of an identical experiment performed by R. Anderson.!^ In
this second study aromatics were found to accumulate to a
greater extent than saturated hydrocarbons. R. Anderson
also collected contaminated oysters from a polluted area of
Galveston Bay, Texas, and transferred them to clean water to
observe depuration processes. Within 52 days tissue hydro-
carbon levels were below 0.1 ppm. This result differs from
the observations described above regarding M. -edulis, which
were not found to depurate readily having grown up in polluted
waters.
Stegeman and Teal exposed two groups of oysters
(Crassostrea virginica) to 106 ppb No. 2 Fuel oil for
different lengths of time and observed hydrocarbon uptake.
The original lipid content of one group was, for unknown
reasons, twice that of the other. Rate of petroleum uptake
was proportional to lipid content. The rate of increase of
the Accumulated oil/original lipid ratio was the same for
9
Anderson, Laboratory Studies of Oil on Marine Organisms.
Roger D. Anderson, "Petroleum Hydrocarbons and Oyster
Resources of Galveston Bay, Texas," in Conference on Preven-
tion and Control of Oil Pollution, U.S. Environmental Protec-
tion Agency, U.S. Geological Survey, American Petroleum
Institute, 1975.
J.J. Stegeman and J.M. Teal, "Accumulation, Release,
and Retention of Petroleum Hydrocarbons by the Oyster
Crassostrea virginica," Marine Biology 22 (1973) : 37-44.
-373-
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the two groups. Hydrocarbon concentrations were 334 ppm
after 50 days exposure, and 161 after 35 days exposure for
the high lipid content group. Uptake was found to increase
to a peak, and then to decrease with increasing time of
exposure. Aromatics comprised a greater percentage of
accumulated hydrocarbons than of the original oil. Forty-
one percent of tissue contamination was aromatics versus
only 15 percent of the fuel oil. This indicates either
selective uptake or selective discharge. For seawater
hydrocarbon concentrations up to 450 ppb the uptake rate is
proportional to hydrocarbon concentration in the medium.
Thereafter the rate falls. At 900 ppb, the oysters remain
closed, and uptake is minimal. Oysters eliminated all but
34 ppm of the accumulated oil upon transfer to clean water.
Twenty-four hour exposure of the clam Rangia cuneata to
0.0305 ppm benzo[ajpyrene resulted in tissue concentrations
of 5.2 to 7.2 ppm benzo[a]pyrene.^2 Accumulation occurred
mainly in the viscera — digestive system, gonads, and
heart. Thirty days depuration left 0.07 ppm of contaminant;
after 58 days less than 0.01 ppm remained.
Anderson found Rangia cuneata to accumulate 3 ppm
n-paraffins and 158 ppm aromatics during a 24-hour exposure
to a 1,000 ppm dispersion of No. 2 fuel oil in seawater.
The mechanism leading to the disproportionate concentration
of aromatics is unknown.
In Mya arenaria (soft shell clam) small micelles of
No. 2 fuel oil appeared to be ingested in the same manner as
food, and were passed directly to the stomach.14 Larger
oil particles were bound by mucus secreted by the gills.
This mucus-oil mixture can later be released or ingested.
12
• Jerry M. Neff and Jack W. Anderson, "Accumulation,
Release and Distribution of Benzo[a]pyrene-C in the Clam
Rangia cuneata," in Conference on Prevention and Control
of Oil Pollution, U.S. Environmental Protection Agency,
American Petroleum Institute, U.S. Geological Survey, 1975.
Anderson, Laboratory Studies of Oil on Marine
Organisms.
14
Dennis M. Stainken, "Preliminary Observations on the
Mode of Accumulation of No. 2 Fuel Oil by the Soft Shell Clam,
Mya arenaria," in Conference on Prevention and Control of Oil
Pollution, U.S. Environmental Protection Agency, American
Petroleum Institute, U.S. Geological Survey, 1972.
-374-
-------
Discharge of the accumulated oil in mucus may present a
hazard to bottom dwelling organisms by enhancing petroleum
concentration in the sediment.
Anderson demonstrated a range of responses of the fish
Fundulus similus to No. 2 fuel oil. Some fish accumulated
oil to a much greater extent than others. Accumulation was
found to occur in the gall bladder, heart, liver and brain.
Complete depuration took 366 hours.
Cod (Gadus morhua) exposed to Kuwait crude accumulated
C15~C33 n-alkanes in the liver.15 C24-C28 n-alkanes were
particularly concentrated, suggesting either selective
accumulation or selective matabolism. An experiment showing
that hexadecane concentrated in cod liver remains unmetabo-
lized indicated that selective accumulation is probable.
The process of selective accumulation is not known.
In summary, it is clear that many organisms do have the
ability to take up and accumulate petroleum hydrocarbons
from their environment. In some cases concentration to
toxic levels can occur. In many cases, however, marine
organisms appear to be relatively unaffected by internal
hydrocarbon accumulation. Some organisms can metabolize
oils; most are able to release the contaminants upon trans-
fer to clean water. There is no evidence for biomagnifi-
cation in the food chain of petroleum concentrations as a
result of accumulation by individual organisms. It is not
clear that bioaccumulation of hydrocarbons has any partic-
ularly significant negative effects on many organisms. More
comprehensive, standardized research in this field is needed
before the mechanisms and consequences of oil accumulation
will be understood.
R. Hardy, P.R. Mackie, and K.J. Whittle, "Discrimi-
nation in the Assimilation of n-alkanes in Fish," Nature
252 (1974): 557-578.
-375-
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TECHNiCAL REPORT DATA
(Plcasr rrnd laanicli(>n* on tin- ret crsc he tor- t f*NO.
5. REPORT DATr
(Date of Issue) May 1977
6. PERFORMING ORGANIZATION CODb
7 AUTHOR(S)
Robert Shore, Joseph Post, Myron Allen,
Lisa Levin, Bill Taffel
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Energy Resources Company Inc.
185 Alewife Brook Parkway
Cambridge, Mass. 02138
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-4177
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Water Planning and Standards
Waterside Mall
Washington, D.C.
13. TYPE OF REPORT ANO PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A study was performed to evaluate the environmental benefits of the EPA
BATEA effluent limitations for the disposal of oilfield brines produced
in coastal oil and gas extraction. For each of four selected locations
(Hackberry Bay, La.; Cook Inlet, Alaska; Grand Isle, La.; and Far Offshore
Gulf of Mexico) data was gathered regarding the composition of the dis-
charged brines, rate of discharge, key hydrodynamic variables influencing
brine dispersion, and the site ecology. A computer dispersion model was
used to calculate the areas around the point of discharge that would be
characterized by a given dilution level. An intensive literature survey
of the toxic effects of oil hydrocarbons and trace metals was used togeth-
er with the dispersion model results to estimate the area of a zone around
each discharge point outside of which impacts could be expected to be
negligibly small. Impacts were found to be highly site-specific in
nature.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI l-'iuld/Groilp
Offshore Oil Production, Oilfield
Brines, Oil Hydrocarbons, Trace
Metals, BPCTC and BATEA Effluent
Limitations, Coastal Waters, Environ'
mental Impacts, Dispersion Modeling,
Toxicity, Water Pollution
13. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Tins Report)
U
21. NO. OH r>AG£S
399
20 SECURITY CLASS (Tin
U
22. PRICE
EPA Form 22:0-1 (9-73)
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U.S. ENVIRONMENTAL PROTECTION AGENCY (WH-586)
WASHINCTON, D.C. 20460 V '
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA-335
SPECIAL FOURTH CLASS
BULK RATE BOOK
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