United States
Environmental Protection
Agency
Research and Development
Environmental Research
Laboratory
Gulf Breeze FL 32561
EPA-600/S3-84-067 July 1984
SEPA Project Summary
Acute Toxicity of Eight
Laboratory-Prepared Generic
Drilling Fluids to Mysids
(Mysidopsis bahia)
T.W. Duke, P.R. Parrish, R.M. Montgomery, S.D. Macauley, J.M.
Macauley, and G.M. Cripe
Acute toxicity tests were conducted
at U.S. Environmental Protection
Agency (EPA) Environmental Research
Laboratories, Gulf Breeze, Florida, and
Narragansett, Rhode Island, with eight
laboratory-prepared generic drilling
fluids (also called muds) and mysids
(Mysidopsis bahia). The test material was
the suspended particulate phase (SPP) of
each drilling fluid. Toxicity of the SPP
ranged from a 96-hour LC50 (the concen-
tration lethal to 50% of the test animals
after 96 hours of exposure) of 2.7% for a
KCI polymer mud to 65.4% for a lightly
treated lignosulfonate mud. No median
effect (50% mortality) was observed in
three drilling fluids — a non-dispersed
mud, a spud mud, and a saltwater-fresh-
water gel mud.
Two of the generic drilling fluids to
which mineral oil had been purposely
added were also tested at Gulf Breeze.
The addition of the mineral oil, even at a
concentration as low as 1 %, dramatically
increased the acute toxicity of both fluids
to mysids.
This Project Summary was developed
by EPA's Environmental Research
Laboratory. Gulf Breeze, FL, to an-
nounce key findings of the research pro-
ject that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
introduction
EPA has permitted the discharge of
eight drilling mud types into U.S. Outer
Continental Shelf waters (EPA, 1983)
under the National Pollutant Discharge
Elimination System (NPDES). This research
project was initiated at the Gulf Breeze
Laboratory to determine the acute toxicity
of these eight generic drilling fluids (Table
1) to representative saltwater crustaceans
(Mysidopsis bahia). The tests were
requested by EPA's Effluent Guidelines
Division, Office of Water Regulations and
Standards, and were conducted according
to methodology prescribed Two of the
drilling fluids were tested at the Nar-
ragansett Laboratory to confirm the valid-
ity of the tests conducted at Gulf Breeze.
Two of the fluids that had been purposely
contaminated with mineral oil were
tested at Gulf Breeze to determine the
toxicity of this additive in representative
drilling fluids
Methods
Test methods followed those proposed
by Petrazzuolo (1983) with the following
exceptions.
(1) Natural seawater was used instead
of artificial seawater, at Gulf Breeze, the
natural seawater was pumped from
Santa Rosa Sound and filtered through
sand and a 5-micrometer fiber filter;
salinity was controlled at 20±2 parts per
thousand by the addition of deioni2ed
water, and temperature was controlled by
a commercial chiller;
(2) 5±1-day-old mysids were used
instead of 4+1-day-old mysids;
-------
Table 1. Source and Reported Composition of Eight Generic Drilling Fluids Received at U S EPA, Gulf Breeze, Florida
Drilling Fluid
Source
Composition
Component
Concentration
EPA-83-001.
KCI Polymer Mud
EPA-83-002,
Sea water
Lignosulfonate Mud
Chromalloy
IMCO Services
EPA-83-003.
Lime Mud
Hughes
EPA -83-004.
Non-dispersed mud
Newpark Drilling Fluids
KCI
Dnspac (Super-Lot
X-C Polymer
Barite
Starch
Seawater
Attapulgite
Chrome Lignosulfonate
Lignite
Polyanionic Cellulose
Caustic
Barite
Seawater
Bentonite
Lime
Barite
Chrome Lignosulfonate
Caustic
Lignite
Distilled water
Bentonite
Acrylic Polymer (for
suspension)
Acrylic Polymer (for
fluid loss control)
Barite
Deionized Water
50 0 grams (g)
0.5 g
1.0 g
283.2 g
2.0 g
257 6 milliliters (ml)
30.0 pounds per barrel
(ppbbl)
15.0 ppbbl
10.0 ppbbl
0.25 ppbbl
TopH 10.5-11.0
To bring mud weight to 17-18 pounds
per gallon (ppg)
As needed
20.06 g
5.01 g
281.81 g
15.04 g
1.00 g
8.02 g
257.04 ml
13.0 ppbbl
0.5 ppbbl
0.25 ppbbl
190.7 ppbbl
299.6 ppbbl
EPA-83-005.
Spud mud
EPA-83-O06,
Sea wa ter/Fresh water
Gel Mud
EPA-83-007,
Lightly Treated
Lignosulfonate Mud
EPA-83-008,
Freshwater
Lignosulfonate Mud
NL Baroid
Milchem
Magobar Dresser
Dowel/
Bentonite
Lime
Barite
Seawater/Freshwater
Caustic
Bentonite
Polyanionic Cellulose
Sodium Carboxymethyl
Cellulose
Barite
Sodium Hydroxide
Seawater/Freshwater. 1:1
Bentonite
Chrome Lignosulfonate
Lignite
Soda Ash
Carboxymethyl Cellulose
Barite
Bentonite
Chrome Lignosulfonate
Lignite
Carboxymethyl Cellulose
Sodium Bicarbonate
Barite
Deionized Water
12.5 ppbbl
0.5 ppbbl
50.0 ppbbl
1.0 bbl
To pH 10.0
20.0 ppbbl
0.50 ppbbl
0.25 ppbbl
20.0 ppbbl
To pH 9.5
As needed
20.0 ppbbl
5.0 ppbbl
3.0 ppbbl
1.0 ppbbl
0.5 ppbbl
178.5 ppbbl
15.0 g
15.0 g
10.0 g
0.25 g
1.0 g
487.0 g
187.0 ml
-------
(3) Test mixtures were aerated, and
(4) For the mineral oil tests, glassware
was washed with petroleum ether to
assure removal of the oil.
To prepare the suspended paniculate
phase of each drilling fluid, 800 milliliters
of chilled seawater were added to a 2-
hter Erlenmeyer flask. Then, 200 milliliters
of the well-stirred drilling fluid were
added to the flask. More seawater (1,000
milliliters) was added to bring the contents
of the flask to the 2-liter mark. This 1 -part
fluid:9-part seawater slurry was placed
on a magnetic stirrer and mixed for at
least 5 minutes. The pH and dissolved
oxygen were measured and, if necessary,
adjusted.
The number of animals exposed to a
drilling fluid and the number of replicates
varied. For range-finding tests, 10 mysids
were added to each of 4 concentrations
and a control, none of which was
replicated. For definitive tests, 20 mysids
were added to each of 5 concentrations
and 3 replications were maintained; a
seawater control and a reference toxicant
(positive control) were also maintained.
The reference toxicant was sodium lauryl
sulfate.
Results and Discussion
Generic Drilling Fluids
The range of toxicity of eight laboratory-
prepared generic drilling fluids to mysids
was considerable. The 96-hour LC50's
were from 2.7% suspended paniculate
phase (fluid #1) to 65.4% (fluid #7). An
LC50 could not be calculated for three
fluids — #4, #5, and #6 — because no
median effect (50% mortality) occurred
(Table 2). It should be noted that these
tests were not designed to identify the
constituents in drilling fluid #1 that
caused it to be more toxic than the other
fluids.
The response of the mysids to the
reference toxicant, sodium lauryl sulfate,
showed that the test animal populations
were in suitable condition for the toxicity
tests. In five tests, the 96-hour LC50's
were from 3.4 ppm to 7.5 ppm. These are
in accord with the literature and with
unpublished data from Gulf Breeze and a
commercial testing laboratory. The
reference toxicant LC50's obtained at
Gulf Breeze and Narragansett were
similar, even though the brood stocks and
natural seawater were different.
The interlaboratory agreement of
drilling fluid test data from Gulf Breeze
and Narragansett was equally good. To
assure the validity of the Gulf Breeze
tests, two of the drilling 'fluids (#1 and #5)
were tested at Narragansett The 96-
hour LC50 for fluid #1 was almost exactly
the same at both laboratories (Table 3)
The results of the tests with fluid #5 were
similar: Narragansett observed no mor-
tality in 100% suspended particulate
phase, whereas Gulf Breeze recorded
12% mortality in that concentration.
Considering the nature of the test
material, this represents a more than
satisfactory duplication of test results.
Mineral Oil-Contaminated
Drilling Fluids
The addition of mineral oil to generic
drilling fluids #2 and #8 dramatically
increased their acute toxicity to mysids.
When 1% mineral oil was added, the 96-
hour LC50 changed from 51.6% to 13.4%
for fluid #2 and from 29.3% to 7.1% for
fluid #8. Addition of 5% and 10% mineral
oil further increased toxicity (Table 4).
There was a significant negative
correlation between mineral oil content
Table 2. Results of Acute Toxicity Tests with Eight Generic Drilling Fluids and Mysids fMysidopsis bahia/ The Tests Were Conducted at U.S. EPA,
Gulf Breeze, Florida, During August-September 1983
Drilling Range-finding Test
Fluid (median effect)
#7 >1%<10%SPPC
#2 >50%1O% <50% SPP
#4 No median effect
in 100% SPP
#5 1OO% SPP
#6 No median effect
in 10O% SPP
#7 >50% <100% SPP
#8 >10% <50% SPP
Definitive Test"
(96 -h LC50 & 95% CL>
2 7% SPP
(2.5-2.9)
51. 6% SPP
(47.2-56.5)
16. 3% SPP
(12.4-20 2)
12% mortality in
100% SPP
12% mortality in
100% SPP
20% mortality in
100% SPP
65.4% SPP
(54.4-80.4)
29. 3% SPP
(27.2-31 5)
Positive Contror
(96-h LC50 & 95% CL)
5 8 ppm"
(4.3-7.6)
7.5 ppm
(6.9-8. 1)
7.3 ppm
(6.6-8.1)
3.4 ppm
(2.8-4.1)
Same as for # 7
6.0 ppm
(5.4-6.6)
Same as for #6
Same as for #3
Definitive Test"
(96-h LC50 & 95% CL)
3.3% SPP
(3 0-3.5)
62. 1% SPP
(58.3-65.4)
20.3% SPP
(15.8-24.3)
—
—
—
68.2% SPP
(55.0-87.4)
30.0% SPP
(27.7-32.3)
"Calculations by moving average, no correction for control mortality unless stated.
"Calculations by SAS®probit; correction for all control mortality. Analyses performed by R. Clifton Bailey, U.S. EPA Program Integration and Evaluation
Staff, WH-586, Office of Water Regulations and Standards, Washington DC 20460
cThe suspended particulate phase (SPP) was prepared by mixing 1 part drilling fluid with 9 parts seawater. Therefore, these values should be multiplied
by 0.1 in order to relate the 1:9 dilution tested to the SPP the whole drilling fluid.
"Corrected for 13% control mortality
-------
and the 96-hour LC50 for each fluid;
Spearmans' r = -0.976 with a probability
<0.0001 (Steel and Torrie, 1980).
Literature Cited
Petrazzuolo, G. 1983. Proposed Method-
ology: Drilling Fluids Toxicity Test for the
Offshore Subcategory; Oil and Gas Ex-
traction Industry. Technical Resources,
Inc., Bethesda, MD 20817. Draft dated
May 19, 1983.
Steel, R.G. and J.H. Torrie. 1980.
Principles and Procedures of Statistics,
2nd ed. McGraw-Hill, New York, NY.
633 pp.
U.S. Environmental Protection Agency.
1983. Issuance of Final General
NPDES Permits for Oil and Gas Opera-
tions on the Outer Continental Shelf
(OCS) of Alaska; Norton Sound and
Beaufort Sea. Federal Register Vol. 48,
No. 236, December 7, 1983, pp.
54881-54897.
Table3. Results of Acute Toxicity Tests with Mysids fMysidopsis babiajand Two Generic Drilling
Fluids Conducted at U.S. EPA, Gulf Breeze, Florida, and Narragansett, Rhode Island,
During August-September 1983
Test Location
Drilling Fluid
96-hour SPPa LC50 95% Confidence Limits
Gulf Breeze
Narragansett
#1
#5
XI
#5
2.7%
No Median Effect*
2.8%
No Median Effect
2.5-2.9%
___
2.5-3 0%
--
'The suspended paniculate phase (SPP) was prepared by mixing 1 part drilling fluid with 9 parts
seawater. Therefore, these values should be multiplied by 0.1 in order to related the 1:9 dilution
tested to the SPP of the whole drilling fluid.
"No median effect (50% mortality) occurred in 100% SPP.
Table 4.
Comparative Acute Toxicity of Two Generic Drilling Fluids without and with Mineral Oil
Tested with Mysids (Mysidopsis bahia^ at U.S. EPA, Gulf Breeze, Florida. During
August-October. 1983
Drilling Fluid*
96-hour SPP" LC50
95% Confidence Limits
#2
#2-07
#2-05
#2-70
tt8
#5-07
na-os
#8-10
51.6%
13.4%
1.08%
0.49%
29.3%
7.1%
0.90
0.76%
47.2-56.5%
11.1-16.9%
1.4-2.2%
0.39-0.62%
27.2-31.5%
5. 7-9.0%
0.74-1.1%
0.63-0.87%
* The two digits following the generic drilling fluid number indicate the percentage of mineral oil in
the fluid.
"The suspended paniculate phase (SPP) was prepared by mixing 1 part drilling fluid with 9 parts
seawater. Therefore, these values should be multiplied by 0.1 in order to re/ate the 1.9 dilution
tested to the SPP of the whole drilling fluid.
The EPA authors, T. W. Duke (also the EPA Project Officer, see below), P. R.
Parrish. R. M. Montgomery, S. D. Macauley. J. M. Macauley, and G. M.
Cripe are with Environmental Research Laboratory, Gulf Breeze, FL 32561.
The complete report, entitled "Acute Toxicity of Eight Laboratory-Prepared
Generic Drilling Fluids to Mysids fMysidopsis bahia,/," (Order No. PB 84-199
850; Cost: $8.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Gulf Breeze. FL 32561
•ft- U S GOVERNMENT PRINTING OFFICE. 1984 — 759-01 5/7744
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $?'.
AlitiViCt
-------
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
Research and Development
EPA-600/S3-84-069 Aug. 1984
&EPA Project Summary
Partitioning of Cadmium, Copper,
Lead and Zinc Among
Paniculate Fractions and Water
in Saginaw Bay (Lake Huron)
Kenneth R. Rygwelski, Jill M. Townsend, and V. Elliott Smith
An intensive study of toxic metals in
Saginaw Bay (Lake Huron) during
1976-1979 has resulted in a large data
base on the temporal and spatial
variability of Cd, Cu, Pb and Zn
concentrations in both the water and
suspended solids. Generally, a trend of
decreasing concentrations of both the
total and dissolved metals from the
inner to the outer bay was observed.
Partition coefficients of all the metals
studied were not constant with respect
to time or space. Particles in the 10-74
/um range were found to contain the
majority of the particulate metal mass
in the water, and they sorbed metals to a
higher degree than the other size
fractions considered.
This Project Summary was developed
by EPA's Environmental Research
Laboratory, Duluth, MN, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Table 1. Sampling Program
Objectives
The distribution of four trace metals,
cadmium, copper, lead, and zinc, was
studied in Saginaw Bay (Lake Huron) in
order to establish a large data base
suitable for future assessment of water
quality trends and the development of
mass balance models for metallic toxins.
A major objective was to determine the
importance of various size fractions of
suspended solids in concentrating trace
metals in the water column.
Methodology
During 1976-78, Cranbrook Institute
of Science carried out an intensive survey
of cadmium, copper, lead, and zinc in
Sagmaw Bay. A total of 33 cruises were
conducted by sampling up to 27 stations
on the bay at approximately two-week
intervals during the months of April-
November. Table 1 lists the numbers and
types of samples collected for the
laboratory analysts of these metals In
addition to these samples, other param-
Year Sampled With Number Collected
Sample Types
Saginaw Bay Cruises
Whole Water
<.45 fjm (dissolved!
.45-10 ym (particulate)
10-74 /jm (particulate)
74-210 /jm (particulate)
210-1000 tint (particulate)
1976
374
336
1977
562
522
1978
313
313
92
92
138
138
Saginaw River Loadings
Whole Water
Precipitation
Whole Water
<.45 fjm (dissolved)
160
11
11
208
93
56
228
122
56
-------
eters measured included chloride, con-
ductivity, non-filterable chlorophyll a, pH,
Secchi disc depth, temperature, total
alkalinity, total non-filterable residue,
and transmittance
A serial filtration system designed for
this study was used to fractionate whole
water into various particle size fractions
(listed in Table 1) to be analyzed for
metals A separate filtration system was
used to filter whole water through a 45 pm
filter to obtain the dissolved fraction
No special pre-treatment was neces-
sary for water samples analyzed for
metals, but paniculate samples were
prepared by using a nitric acid digestion
method Samples were then analyzed
using flame and flameless atomic absorp-
tion spectrophotometry
Care was taken in choosing equipment
made of materials that would minimize
contamination in all phases of the sample
collection, filtration, digestion, and
analysis Routine blank checks were
made on sample bottles, the filtering
process, and on paniculate filters and
screens
Accuracy of the metal analysis was
determined through participation in
interlaboratory comparison studies and
by analysis of standard reference samples
and use of the standard addition method
Results of between-run analyses of
standards and samples were used to
determine precision
Results
The full report contains an overview of
the data and describes the spatial and
temporal distribution of zinc, copper, lead
and cadmium in Saginaw Bay Partition
coefficients of all the metals studied were
not constant with respect to time or
space Two types of partition coefficients
were determined, a Kpg (general Kp) and a
KpS (specific Kp). For all four metals, the
Kps calculated for each of the specific size
fractions (10-74 /urn, 74-210 pm, and
210-1000 /um) were within the range of
the Kpg values calculated using total non-
filterable residue data Particles in the
10-74 fjm range were found to contain
the majority of the paniculate metal mass
in the water and exhibited the highest Kps
of these metals.
Partition coefficients (Kps and Kpg) in
Saginaw Bay increased as the suspended
solids concentration decreased This
trend held for cadmium, copper, zinc, and
lead (Figures 1-4) Segment 4 was
chosen to represent the largely oligotro-
phic outer bay, and segment 1 was typical
of the eutrophic inner bay.
08 .
0.6
0.4 .
0.2 .
10
Figure 1.
7CT1 10° 701
Suspended So/ids Concentration (ppmj
General partition coefficients for cadmium, 1976.
1C
08 -
0.6 -
04 .
0.2 -
Segment 1 -
Segment 4 -
10*
\i(f
\
\
704
70"
70"
T
70°
1
70'
702
n
Figure 2.
Suspended So/ids Concentration (ppm)
General partition coefficients for copper, 1978.
-------
c
o
03
£
0.8 -
0.6 -
04 .
02 -
10*
Segment 1 - •
Segment 4 - °
10
10° 10"
Suspended So/ids Concentration fppm)
102
JO3
Figure 3. General partition coefficients for zinc, 1976-1978
02 -
The figures also show that the fraction
of metal dissolved increases within a
given segment as the suspended solids
concentration decreases This trend is
predicted by theory if constant partition
coefficients can be assumed within a
given segment
Data for cadmium, copper, lead, and
zinc as total metal, dissolved metal,
particulate metal mass in the water, and
the concentration of metal in the particles
are presented in figures and tables
contained in the full report
Gradients of decreasing concentration
from the inner to outer bay segments
were noted for total and dissolved metals
studied and for other non-metal param-
eters, including total non-filterable
residue, conductivity, chloride, alkalinity,
and non-filterable chlorophyll a. Quarter-
ly and annual summaries of all non-metal
parameters are presented by bay seg-
ments
Recommendations
These results indicate an inverse
relationship between the solids concen-
tration and partition coefficients of these
metals in Saginaw Bay Such a "mass
effect" has been noted elsewhere.
However, it is possible that the chemical
nature of particulates and of adsorbing
metal species also plays an important role
in partitioning If all of these variables
were well defined in Saginaw Bay, in both
space and time, then it would be possible
to predict partition coefficients in other
fresh water systems. Complete charac-
terization of these variables was not
possible in this study, until such data are
available, an empirical approach such as
the one used here is probably most
appropriate to define partitioning.
Quality control measures are an
important consideration in any study,
particularly one involving analysis of
trace metals Determining blank levelsfor
equipment and processes used in the
study was crucial to providing accurate
results Results of such quality control
programs should be used in establishing
analytical strategies and determining the
reliability of the data generated.
It was difficult to compare these data to
those of previous studies, as little parti-
tioning data on metals exists. It is hoped
that these results will provide a needed
base of information on trace metal
partitioning in waters of the Great Lakes.
Suspended Solids Concentration (ppm)
Figure 4. General partition coefficients for lead, 1977-1978.
-------
K. R. Rygwelski, J. M. Townsend, and V. E. Smith are with Cranbrook Institute of
Science, Grosse lie. Ml 48138.
V. J. Bierman is the EPA Project Officer (see below).
The complete report, entitled "Partitioning of Cadmium, Copper, Lead and Zinc
Among Paniculate Fractions and Water in Saginaw Bay (Lake Huronj," (Order
No. PB 84-209 899; Cost: $16.00. subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Narragansett. Rl 02882
U.S GOVERNMENT PRINTING OFFICE, 1984 — 759-015/7761
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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