NC0023965_Report_19861001

Wilmington Northside WWTP
Toxicity Examination
NPDES#NC0023965
III I[at It
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North Carolina Department of Natural
Resources & Community Develop
/`PENILE
Bioassey and Biomonitoring
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NORTH CAROLINA DEPARTMENT OF NATURAL
RESOURCES AND COMMUNITY
DEVELOPMENT
WATER QUALITY SECTION
October,, 1986
5d

WILMINGTON-NORTHSIDE WWTP
TOXICITY EXAMINATION
NPDES •NC0023965
NORTH CAROLINA DEPARTMENT OF NATURAL RESOURCES
AND COMMUNITY DEVELOPMENT
DIVISION OF ENVIRONMENTAL MANAGEMENT
WATER QUALITY SECTION
October 1986

TABLE OF CONTENTS
Page
List of Figures and Tables ................................................. i
Introduction............................................................... 1
Toxicity Examination....................................................... 2
Chemical Sampling.......................................................... 11
Organic Analysis........................................................... 18
Conclusions................................................................ 20
Recommendations............................................................ 22
Footnotes... .............................................................. 23
Appendix................................................................... 25
Daphnia oulex Test Procedure .......................................... 26
96 Hour Flow -through Test Procedure ................................... 27
Ceriodeohnia Reproduction Test Procedure .............................. 30
List of Definitions................................................... 31
LIST OF TABLES
Page
Table 1. Industrial Contributors to Wilmington-Northside WWTP............ 2
Table 2. 96 Hour Fathead Minnow Mortality.. 5
Table 3. Cy'stocerp Formation in the Champia Bioassay ..................... 10
Table 4. Sampling Site Descriptions... .................................... 12
Table 5. R a a u I t 3 of Chemical AnaIya13.................................... 14
LIST OF FIGURES
Page
Figure I. Schematic of Wilmington-Northside WWTP.......................... 3
Figure 2. 96 Hour Fathead Minnow (Pimephetes promotes) Mortality
Wilmington-Northside WWTP....................................... 6
Figure 3. Seven Day Ceriodeohnia Mean Cumulative Reproduction........: 8
Figure 4. Seven Day Ceriodeohnia Mortality ................................ 9
Figure 5. Wilmington-Northside WWTP Study Area ............................ 13
-i-

WILMINOTON-NORTHSIDE WWTP
INTRODUCTION
An on -site toxicity examination was conducted at the Wilmington-Northside
Wastewater Treatment Plant (NPOES Permit No. NCO023965) from April 28 through
May 3, 1986. The Wilmington-Northside WWTP, located in New Hanover County,
serves the City of Wilmington and 5 major industrial facilities (see Table 1).
These facilities contribute 1.61% of the wastewater treated by the plant at peak
fIowa .
This document details the findings of biological and chemical analyses,
including the following:
1.) 48 hour static bioassay using Daphnia up lex on both effluent and
influent samples to determine acute toxicity.
2.) 96 hour flow -through bioassay using Pimeohales Dromelas (fathead
minnows) performed on effluent collected from the two final clarifiers
prior to chlorination.
3.) Seven day Ceriodaohnia reproduction bioassay to assess sub -lethal
toxicity.
4.) Seven day Champia oarvula (marine red macroalga) reproduction bioassay
to assess chronic toxicity.
5.) Chemical analyses of samples collected from the plant influent and
effluent, and from the receiving stream.
The Wilmington-Northside WWTP discharges into the NE Cape Fear River (Class
SC -SW). Permitted flow of the facility is 8.0 million gallons per day (MOD)_
The 7 day, 10 year low flow (7010) of the NE Cape Fear is 28 cubic feet per sec -
and lets). At maximum permitted flow during 7010 stream conditions, the facil-
ity's effluent produces an instream waste concentration (IWC) of 30.69%. This
30.69% IWC though is short lived as the Northeast Cape Fear River converges with

the Cape Fear River approximately 300 ft. below the Wilmington North 1WVTP's dis-
charge. With a combined 7010 flow at this confluence of 1149 cfs, the instream
waste concentration drops to 1.07%. Since toxic substances will be allocated for
the northeast Cape Fear River, 30.69% will be used throughout this report as the
facility's IWC. From January 1984 until July 1986 the facility has submitted
thirty-one (31) monthly self -monitoring compliance reports. Results from these
reports indicate no permit exceedences until December 1985. The facility was in
exceedence of their permitted 800 level for five of the last eight months (Decem-
ber 1985 through July 1986).
Waste treatment processes at the facility include influent lift station, bar
screen, comminutor, grit chamber, dual primary clarifiers, dual high rate trick-
ling filters, dual secondary clarifiers, effluent chlorination facilities, heated
sludge digestion tanks and sludge drying beds. A schematic of the Wilmington-
Northside WWTP is presented in Figure 1.
Table 1. Industrial Contributors to Wilmington-Northside %WTP
Industry
Category
Corning Glass Works Pressed R blown glass Mfg
Wilmington Coca-Cola Soft drink mfg.
Textilease, Inc. Industrial launderers
Pepsi -Cola Bottling Co. Soft drink mfg.
Kenan Transport Co. Long distance trucking
TOXICITY EXAMINATION
Flow (aal/day)
50,000
35,000
30,000
8,000
6,000
An on -site toxicity examination was conducted at the Wilmington-Northside
WWTP due to effluent toxicity indicated by a series of three Daphnia uD Iex /8
hour static bioasseya performed by Divisional personnel and the fact that the
facility was experiencing (periodic) operational difficulties (i.e. high 800 and
solids) associated with sudden algal met die -offs in the trickling filters. Test
dates and resulting LCbo values of the three D. pulex tests were: 3/10/86-55%;
f
-2-

Figure 1. Schematic of Wilmington-Northside WWTP
Comminutor
Bar
Anaerobic
Sludge
Station 02A-
Grit Chamber
Sludge
Drying
Beds
Primary
Clarifier
Primary
Clarif ier
Chlorine
Contact
Chamber
to NE Cape
Fear River
Sludge
Wastewater
Trickling
Filter
Trickling
Filter
Secondary
Clarifiers
Station 02-Bioassay
Sampling Points
Secondary
Clarifiers
-3-

3/27/86-49%1 and 4/3/86-84%. The LCae value Is the concentration o1 effluent
lethal to fifty percent of the test organisms.
Beginning in May of 1986 the North Carolina Division of Environmental Mana-
gement (NC DEM) required that the Wilmington-Northside WWTP begin monthly self -
monitoring bioassays (acute) of composite effluent samples. Results of these
tests are as follows:
Test Date Test Type LQjI
May 1986 48 hr D. oulex Not Reported
June 1986 " 35.48%
July 1986 44.67%
August 1986 44.67%
On -site bioassays included a 96 hour flow -through acute bioassay using
fathead minnows (Pimepholes promelas), a Ceriodaphnia dubia reproduction
bioassay, and 48 hour static Daphnia pulex bioassays performed on influent and
effluent samples. Additionally, an effluent sample was collected and sent to
the U.S. EPA Environmental Research Laboratory in Narragansett, Rhode Island for
performance of a Champia parvula reproduction bioassay. All effluent bioassay
samples were collected prior to chlorination. The test fish, D. pulex and
Ceriodaphnia, were obtained from cultures maintained at the NC DEM Aquatic Toxi-
cology Laboratory. Dilution water for all on -site tests was obtained from the NE
Cape Fear River at the Castle Hayne boat ramp. This water was tested prior to
use at the NC DEM Aquatic Toxicology Laboratory using the Ceriodaphnia reproduc-
tion bioassay. Reproduction in this water was similar to that of laboratory cul-
ture water.
The 96 hour flow -through bioassay was initiated at 09:00 on April 29, 1986
and continued until 09:00 on May 3, 1986. The test organisms, 50 day -old fathead
minnows, were transferred to test chambers with dilution water approximately 15
hours prior to test initiation. The fish had been acclimated to the dilution
water (NE Cape Fear River water) approximately 96 hours before transfer to the
-4-

test chambers. The toxicant delivery system mounted in the NC DEM mobile labo-
ratory produces six concentrations of effluent and control water (100% dilution
water). These concentrations are 5%, 10%, 25%. 50%, 75% and 100%. The diluter
system delivers each solution to two test chambers containing ten fish each. At
the Wilmington-Northside IAWTP the toxicant delivery system cycled 562 times dur-
ing the flow -through test, yielding a 90% replacement of test solutions in the
fish chambers approximately every 1.5 hours. The final 96 hour mortality data is
listed in Table 2. The 96 hour LC,, for this data was calculated as 86% by
Trimmed Spearman Kerber and is presented graphically in Figure 2.
Table 2. 96 Hour Fathead Minnow Mortality
Effluent d
Concentration (%)
Mortality (%)
0
0
5
0
10
0
25
0
50
0
75
10
100
80
Daphnia up lex bioassays were conducted on -site for both influent and
effluent samples. A forty-eight hour LCso value of 28% was determined using an
instantaneous grab of influent on May 1, 1986. The effluent bioassay, using a
twenty-four composite sample, yielded a 24 hour LC,, of 53% with a 48 hour LCso
of 52%. After 96 hours of aeration, the sample was again tested as a toxicity
persistence sample as specified by EPA/600/4-85/0131. The persistence test
showed no acute toxicity, defining the waste toxicity as "non -persistent'.
A seven-day Ceriodaphnia static replacement bioassay was performed on dilu-
tions of effluent in order to assess sub -lethal toy,city. as well as chronic

Figure 2. 96 Hour Fathead Minnow Mortality, Wilmington Northside WWTP
i:3
T
0
x
c
A
N
T
V
O
L
u
M
E
m.,
10
LOG -CONCENTRATION VS R MORTALITY
0 10 20 30 40 s0 60
R MORTALITY
LC =88%
50
70 80 90 100
cm

mortality effects. This test was initiated on -site at the Wilmington-Northside
WWTP on April 28, 1986 and was concluded at the Aquatic Toxicology Laboratory on
May 5, 1986. Dilution water for this test was obtained from the NE Cape Fear
River at Castle Hayne. Mean cumulative reproduction of this test is presented in
Figure 3. Al the conclusion of the seven-day period, a statistically significant
decrease in reproductive success was observed in the 10% test concentration.
Reproduction similar to that of the controls was recorded in the 1%, 0.1% and
0.01% effluent concentrations. For this test, 10% effluent represents the Lowest
Observed Effect Concentration (LOEC), while 1% effluent represents the No
Observed Effect Concentration (NOEC). In all concentrations of 10% and greater,
complete organism mortality occurredi all Ceriodaphnia died within 148 hours
after exposure to 10% effluent, while none of the organisms survived more than 48
hours in the 25%, 50%, 75% and 100% test concentrations (and consequently pro-
duced no young). A 168 hour LCea of 3.2% effluent was calculated (see Figure 4).
The calculated Chronic Value (ChV) for this test, which is the geometric mean of
the LOEC and NOEC, is 3.16%.
A seven-day Champia parvula (marine red macroalga) chronic bioassay was
initiated April 30, 1986 on a composite effluent sample collected April 29, 1986.
The bioassay was conducted at the U.S. EPA Environmental Research Laboratory in
Narragansett, Rhode Island. This test was performed to determine the toxicity
(i► any) Wilmington-Northside WWTP's effluent has on a saltwater organism. The
experimental method, in brief, uses the absence of sexual reproduction (evidenced
by cystocarp formation) as the endpoint. Male and female plants are exposed to
various effluent concentrations for 48 hours, followed by a 5 to 7 day recovery
in control medium (dilution water used was from Narragansett Bay. RI). The
recovery period allows time for cystocarpa to mature. At the end of the recovery
period the number of cystocarpa (fertile reproductive structures) per plant are
-7-

Figure 3. Seven Day Ceriodaphnia Mean Cumulative Reproduction
Mean Cumulative Reproduction
40
30 -L I *' Control
a .019
} 0.1T
Mean Young 1%
Produced
10%
20
10
0
2 3 4 S 6 7
Day of Test
Wilmington-Northside WWTP
-8-

Figure 4. Seven Day Cerlodaphnia Mortality, Wilmington Northside WWTP
T
0
x
i
c
A
N
T
v
O
L
u
M
E
m
10
1
LOG -CONCENTRATION VS %MORTALITY
O 10 20 30 40 50 60 70 80 90 100
96 MORTALITY
LC =3. 16%
50
-9-

counted. For the 48 hour exposure, a 195% decrease from the control is consid-
ered 'zero". Results from this bioassay are presented in Table 3. No necrotic
Plant tissue was observed at any of the concentrations tested. This suggests
that the effluent was not lethally toxic to Chamoia, however sexual reproduction
was significantly reduced at the 5% concentration, with no reproductive activity
observed in Chemoie exposed to 10 and 15% effluent. The calculated ChV for the
Chamoia test is 3.53%, which is very similar to the Ceriodaohnia test CAV of
3.16%. This indicates that the Wilmington-Northside NWTP effluent has the poten-
tial for strong chronic impact to the Northeast Cape Fear River during 7010 flow
conditions at an instream waste concentration of 30.69%, but probably does not in
the lower Cape Fear River es the IWC drops to 1.07%.
Table 3
% Effluent
Control
0.63
1.25
2.5
5.0
10.0
15.0
Cystocarp Formation in Chemoie oarvula Bioassay
Replicate Values•
A
B
C
15
13
17
9
13
11
15
18
11
14
17
20
6
6
7
0
0
0
0
0
0
Each replicate is the mean of five plants.
• Mean is statistically less than control.
Mean = SD
15 : 2
11 t 2
15 1 4
17 t 3 (NOEC)
7 s to (LOEC)
0
0
On April 2, 1986 Aquatic Toxicology Group personnel conducted a pre -test
survey at the Wilmington-Northside WWTP. At that time, plant personnel indicated
they believed one reason the facility was experiencing periodic organism "die -
offs" in the trickling filters (and subsequent high BOD's) was due to a buildup
of toxic substances in the sludge digester
Consequently it was suspected that

constituents In the digester supernatant were inhibiting normal microbial pro -
ceases within the treatment plant.
The NC DEM collected a 24 hour composite sample of the digester supernatant
on April 14-15, 1986. A 48 hour Daphnia up lex bioassay was run on this sample
April 16, 1986. Due to extremely heavy suspended solids in the sample, it was
centrifuged at 3700 RPM for 5 minutes, and the test was performed on the decanted
portion of the sample. The 48 hour LCeo was 1.6%, indicating that the superna-
tant was highly toxic to 0. up lex.
Concurrent with the DEM test, the City of Wilmington contracted an indepen-
dent laboratory to analyze a 24 hour composite sample of digester supernatant.
Analysis of the sample received April 22, 1966 indicated a level of nonyl phenol
(est. 6000 ppb) (tentatively identified) substantially greater than the 96 hour
nonyl phenol LCeo for fathead minnows of 140 ppba. Since the on -site investiga-
tion, the facility has been slowly releasing this digester supernatant through
the sludge drying bed drainage system to remove heavy solids and recirculating
this waste back through the influent and subsequent treatment processes.
CHEMICAL SAMPLING
Two series of chemical samples collected during the evaluation were analyzed
at the Division of Environmental Management Chemistry Laboratory. Table 4 lists
descriptions of the sampling stations. All samples were collected as instanta-
neous grabs with the exception of Station 02 samples (effluent bioassay sampling
point) which were taken as 24 hour composites. Figure 5, a map of the study
area, illustrates sampling site locations. Results and summaries of chemical
analyses are documented in Table 5.
Metals analyses revealed copper concentrations of 40 ppb and 55 ppb in the
effluent samples (02) of May 1 and 3, respectively_ At these concentrations and
7010 conditions, the concentration in the receiving stream would average 14.6
ppb, assuming receiving stream concentrations of zero. This value approaches the
-11-

N.C. Water Quality Action Level of 10 ppb for copper. Copper was not detected
(lower detection limit (10 ppb), in the upstream, downstream, or dilution water
sites for either sampling date. Elevated levels of zinc were detected in the
effluent for both sampling dates, with 95 ppb on May 1 and 110 ppb on May 3. At
these concentrations and 7010 conditions, the concentration in the receiving
stream would average 31.5 ppb. The North Carolina Water Quality Action Level for
zinc is 50 ppb. Influent (02A) levels were 100 ppb (May 1) and 70 ppb (May 3)
indicating the variable nature of the influent (in terms of zinc content) and
that the WWTP's removal efficiency for zinc appears low. No zinc was detected at
the downstream site (03) or dilution site (04) on either sampling dale. However,
small amounts were found in upstream samples (01) on May 1 and May 3 with 12 ppb
end 15 ppb detected on each day, respectively.
Table 4. Sampling Site Descriptions
Station 01
- N.E. Cape Fear River
at railroad bridge -
upstream of the Wilming-
ton-Northside WWTP.
At this point the river
is approximately 60 m?
wide.
Station 02
- Wilmington-Northside
WWTP effluent at the
overflow weirs of the two
secondary clarifiers.
Thia is the bioassay
sampling point for the
Daphnia oulex static
tests.
Station 02A
- Wilmington-Northside
WWTP influent, just
prior to the influent bar
screen.
Station 03
- The Cape Fear River
at the Castle Street
boat ramp - downstream of
Wilmington-Northside
WWTP discharge. At
this point the river is
approximately 80 m wide.
Station 04 -
N.E. Cape Fear River
at the Castle Hayne
boat access ramp. Here
the river is approximately 50 m wide.
-12-

Figure 5 . Wilmington Northside WWTP Study Area.
-13-

Table 6 . Chemical Analyses- Wilmington North WWTP
Permitted Flow MG
8
7Q10 CPS
28
Chemical Ph ical
Units
Water Qual.
Sta 01
Sta 02
Sta 02
Sta 03
Sta 04
Sta 02B
Analyses
Standards
860501
860501
860501
860501
860501
860501
BOD
PPM
1.1
451
1401
1.3
1.2
COD
PPM
300
17OF
5101
340
44
Coliform: MF Fecal
s 100ml
60
6000001
700
70
290
480000
Coliform: Tube Fecal
s 100m1
Residue TOTAL
PPM
11000
5001
430
12000
170
volatile
PPM
2200
851
140
2100
52
fixed
PPM
8700
4101
2901
9700
120
Residue SUSPENDED
PPM
27
261
79
56
2
volatile
PPM
9
18
67I
11
2
fixed
PPM
16
8
12
45
<1
H standard units
4.3-8.5
6.9.
7.4
6.9
7.5
7.1
Acidity
PPM
101
301
34
10
12
Alkalinity
PPM
52
1501
1401
56
27
Arsenic
PPB
<101
<10
Chromium Hex
PPB
<50
Cyanide
PPM
0.02
<0.1
Fluoride
I PPM
1
1.4
I
Formaldehyde
PPM
<0.1
<0.1
Grease and Oils
PPM
27
Hardness
PPM
18001
72
70
1800
52
MBAS
PPM
1.6
Phenols
PPB
7
28
Silver
PPB
<251
<25
<25
<25
<25
Specific Conductance
Mhos cm
140001
790
630
13000
180
NH3
PPM
0.181
24
19
0.17
0.04
TRN
PPM
0.71
27
26
0.6
0.5
NO2 NO3
PPM
0.341
1.1
0.03
0.36
0.11
P. total
PPM
0.12
7.9
5.6
0.14
0.07
Aluminum
PPB
3501
200
400
5001
200
Cadmium
PPB
2
<10
<10
<10
<10
<10
m Chromiu
PPB
20
<251
<25
<251
<251
<25
Copper
PPB
10 AL t !
<101
401
35
<101
<10.
Iron
PPB
1000
6901
690
11001
8901
490
Mercury
PPB
0.1
<0.2
<0.2
<0.2
<0. 21
<0.2
Manganese
PPB
130
50
45
140
25
Nickel
PPB
50
<50
<50
<50
<50
<50
Lead
PPB
25
<50
<50
<50
<50
<50
Zinc
PPB
50 AL
12
95
100
<10
<10
t Values represent action levels as specified in _0212 b 4
Tidal Salt Water Classifications Standards
-14-

Table 5 . Chemical Analyses- Wilmington North WWTP
Permitted Flow MGD
8
7Q10 CFS
28
Chemical Ph ical
Units
Sta 01
Sta 02
Sta 02A
Sta 03
Sta 04
Predicted stream
Analyses
860503
860503
860503
860503
860503
conc. at 7Q10**
BOD
PPM
COD
PPM
280
220
310
230
45
59.846
Coliform: MF Fecal
• 100ml
Coliform: Tube Fecal
• 100ml
Residue TOTAL
PPM
11000
470
460
11000
170
volatile
PPM
1700
89
150
1800
58
fixed
PPM
9100
390
310
9100
110
Residue SUSPENDED
' PPM
31
34
86
34
2
volatile
PPM
5
27
791
6
1
fixed
PPM
26
7
7
28
1
H standard units
7.4
7.5
6.8
7.3
6.6
Acidity
PPM
7
29
52
8
15
Alkalinity
PPM
48
160
120
49
21
Arsenic
PPB
<10
<10
Chromium
PPB
<50
Cyanide
PPM
1 0.021
<0.01
0.006
Fluoride
PPM
1
Formaldehyde
PPM
<G. li
<0.1
Grease and Oils
PPM
Hardness
PPM
1700
661
64
1700
52
MBAS
PPM
Phenols
PPB
8
37
Silver
PPB
<251
<25
<25
<25
<25
Specific Conductance
Mhos cm
13000
770
640
12000
200
NH3
PPM
0.26
21
20
0.18
0.02
6.905
TKN
PPM
0.5
30
36
0.6
0.3
8.747
NO2 NO3
PPM
0.38
0.74
0.05
0.42
0.11
0.282
P. total
PPM
0.13
9.1
6.2
0.16
0.071
2.609
Aluminum
PPB
600
200
200
600
150
61.380
Cadmium
PPB
<10
<10
<10
<101
<10
<3.1
Chromium
PPB
<25
<25
<25
<251
<25
<7.7
Copper
PPB
<10
55
30
<10
<10
14.578
Iron
PPB
1000
740
790
990
420
219.434
Mercury
PPB
<0.2
<0.2
<0.2
<0.2
<0.2
<.06
Manganese
PPB
220
50
50
140
<251
15.345
Nickel
PPB
<50
<50
<50
<50
<50
<15.3
Lead
PPB
<50
<50
<50
<50
<50
<15.3
Zinc
PPB
15
110
70
<10
<10
31.457
"Values represent predicted instream concentrations using average effluent
concentrations permitted facility flow and assuming upstream levels of 0 .
-15-

Table 6 (cont.). Chemical Analyses- Wilmington North WWTP
Predicted
Organic Analyses
Units
Sta 02
Sta 02A
Sta 02
Sta 02A
Toxicity
0.2961585
Foot
stream
860501
860501
860503
860503
Value
(S)=static
note
concen.
(PPB)
(F)-flowthrough
at 7Q101
PPB
y-chlordanett
PPB
0.13**
0.14**
LC50=24
48hr D. pulex(S)
7
0.041
LC50-3
96hrLM bass 3
8
diazinon*
PPB
0. 73*x
1.2**
EC50=0.9
48hr D. pulex(S)
9
0.296
EC50=0.8
48hr D. pulex(S)
7
methylene chloride*
PPB
9200**
3700**
6600**
LC50=193000
96hr fathead(S)
10
2424.510
LC50=224000
48hr D.maitna
8
trichloroethene*
PPB
0.12
0.14
0.28
LC50=44100
96hr fathead F
2
0.043
tetrachloroethene*
PPB
1.6
0.75
LC50=13400
96hr fathead(F)
2
LC50=20300
96hr fathead F
2
chloroform*
PPB
13
1.9
8.9
LC50-29000
48hr D.ma na S
11
0.583
1 1 1 trichloroethane*
PPB
2.1
0.34
5.6
LC50=52800
96hr fathead F
10
0.009
non 1 phenol
PPB
3
LC50=140
96hr fathead F
2
toluene*
PPB
5.2
TLM=34000
96hr fathead
12
a methyl styrene
PPB
4
1.228
methoxy methylethoxy
PPB
22
5
22
6.752
propanol
methylethoxy butane
PPB
7
2.140
bromoryclohexane
PPB
1
0.307
caffeine
PPB
1
1
11
0.307
O-decyl hydroxylamine
PPB
1
0.307
total alkanes
PPB
1
85
0.307
methoxy propoxy
PPB
3
propanol
dimeth 1 trisulfide
PPB
6
methyl methylethyi
PPB
5
clohexane
eicosyl cyclohexane
PPB
11
chlorodibromomethan
PPB
0.11
methyl methylethenyl
PPB
24
cyclobexane
bromodichlorarnethanEl
PPBI
1
0.74
1 1 dichloroethane* I
PPBj
I
1
1
3.7
unidentified peaks I
• 1
91
181
Of
5
tValues represent predicted instream concentrations using single or average effluent
concentrations and assuming upstream concentrations of 0 and permitted discharge
UNC Water Quality Standard for Chlordane is 0.004 PPB.
f low.
*Included in NC Water Quality Standards list of Chemicl Substances Requiring
Special Attention
=;Concentration greater than 1 300th of the stated LC50
MGfl

An examination of available toxicity data for these two metals (copper and
zinc) indicate that their concentrations were high enough in the effluent to have
caused the observed toxicity in both the Daphnis pulex and Ceriodaphnia dubia
tests performed on -site. Copper LCso's have been reported as low as 9.8 ppb for
18 hour Dpphnia Magna bioassays in water of 15 ppm hardness'. Zinc LCse's for
p. pulex have been reported as 107 ppb in water hardness of 15 ppm with an LCso
of 76 ppb for Ceriodaohnia dubia'. It is unlikely that these metals caused the
observed mortality in the 96 hour fathead minnow flow -through test as they are
much more tolerant of these metals than are cladocerens. Ninety-six hour LCso's
of 490 ppbs and 600 ppb• have been reported for fathead minnows exposed to copper
and zinc, respectively.
The total suspended residue level in the May 3 effluent sample was 31 ppm.
This value would indicate a possible exceedance of the permitted effluent limi-
tation (30 ppm monthly average) if concentrations remain at the encountered
level.
Although no cyanide was detected (detection limit 10 ppb) in the influent on
either sampling date, it was detected at a concentration of 20 ppb in the efflu-
ent on both sampling dates. At these concentrations and 7010 conditions, the
concentration in the NE Cape Fear River would average 6.1 ppb (assuming a back-
ground concentration of zero). Cyanides are used primarily in electroplating,
metal treatment, and various manufacturing processes. Cyanide is also an EPA
Hazardous Substance and Priority Toxic PollutantlD. The highest no -effect level
of hydrogen cyanide for the fathead minnow in a 256 day life -cycle test has been
estimated to lie between 12.9 and 19.6 ppb (based on statistical evaluation of
egg production)14. It is predicted from this data that the amount of cyanide
contributed to the receiving stream (at encountered levels) will not be either
acutely or chronically toxic, due to dilution in the NE Cape Fear River.
-17-

Effluent ammonia levels of 24 and 21 mg/I were reported for the two sampling
dates, respectively. Assuming an effluent pH of 7.5 (7.5 and 7.4 were reported
values) and temperature of 20°C, the percent of total ammonia that would exist in
the un-ionized form (NHe) would be approximately 1.24%. This would yield actual
effluent concentrations of NHe of 0.3 mg/I and 0.26 mg/I. The "chronic effects
threshold" level of ammonia based on survival, growth, and reproductive success
of fathead minnows has been reported as 0.27 mg/I but drops to 0.15 mg/l based on
histological damage (brain lesions) caused by chronic exposure's
ORGANIC ANALYSIS
Organic chemistry analyses of the composite effluent sample collected May 1
revealed 10 identified compounds and nine unidentified compounds (Table 5).
Three of the identified compounds which are of particular concern were methylene
chloride detected at 9200 ppb, diazinon at 0.73 ppb, and gamma -chlordane at 0.13
ppb_ Both diazinon and methylene chloride are listed among the "Chemical Sub-
stances Requiring Special Attention" (further referred to as CSRSA) in the NC
Water Ouality Standards"•. Analyses of the May 3 composite effluent sample
revealed nine identified and 8 unidentified compounds. Compounds of special con-
cern that were detected are methylene chloride at 6600 ppb, diazinon at 1.2 ppb,
gamma-chlor dens at 0.14 ppb, chloroform at 1.9 ppb, and 1,1,1-trichloroethane at
0.34 ppb. From available toxicity data (see Table 5) It can be seen that diazi-
non, with reported 48 hour Daphnia oulex ECao's of 0.8 ppb and 0.9 ppb most
likely contributed to the chronic toxicity observed in the Ceriodaphnia dubia
life -cycle bioassay. Diazinon is an insecticide used for a wide variety of
applications including agricultural.crops, ornamentals, lawns and gardens, and
domestic animals. Although it is unlikely that chlordane caused any of the
observed toxicity, effluent concentrations were high enough such that the pre-
dicted average instream concentration at 7010 conditions (0.0/ ppb) would exceed
sm

the N.C. Water Duality Standard for chlordane (0.004 ppb) by a factor of ten.
Chlordane is a non -systemic organochlorine insecticide.
Neither of the two influent samples analyzed contained detectable amounts of
the two insecticides (diazinon and chlordane), but did contain other CSRSA. The
influent grab sample on May 1 contained methylene chloride at 3700 ppb, trichlo-
roethene at 0.12 ppb, 1,1,1-trichloroethane at 2.1 ppb, tetrachloroethene at 1.6
ppb, chloroform at 13 ppb, chlorodibromomethane at 0.11 ppb, and bromodichloro-
methane at 0.74 ppb. Eighteen unidentified compounds were also detected in this
sample. Two compounds of concern that were unique to the May 3 Influent sample
were toluene at 5.2 ppb and 1,1-dichloroethane at 3.7 ppb. Five unidentified
compounds were also detected in this sample.
It is worth noting that the influent samples contained five (5) CSRSA not
detected in the effluent samples and that the two insecticides present in the
effluent were not detected in the influent. This variation in influent consti-
tuents versus effluent constituents serves to illustrate the variable nature (in
terms of contents) of the waste stream the Wilmington-Northside WWTP receives.
From an examination of all chemical analyses and available toxicity data, it
appears the fathead minnow mortality observed in the 96 hour flow -through bioes-
say cannot be attributed to one specific causative agent (i.e. metals or organic
compound). The toxic response was probably due to combined or additive effects
from constituents in the effluent.
Due to the amount of dilution that the Wilmington-Northside WWTP wastewater
receives in the Northeast Cape Fear and Cape Fear Rivers, benthic macroinverte-
brate samples were not collected for this investigation.
-19-

CONCLUSIONS
On -site toxicity tests conducted on the effluent of the Wilmington-Northside
WWTP resulted in a 96 hour fathead minnow LCso o1 88%, a Daphnia up lex 48 hour
LCso of 52%, a Ceriodephnis dubia 168 hour LC,* of 3.2% with a calculated chronic
value of 3.16%, and a Champia parvule calculated chronic value of 3.53%.
Analyses of chemical samples show elevated effluent concentrations of cop-
per, zinc, cyanide and ammonia. Both copper and zinc were present in sufficient
concentrations to have caused acutely toxic responses in the cladoceran test
species. Organic constituents identified in the effluent present in sufficient
concentration to have contributed to observed toxicities include gamma -chlordane
and particularly diazinon, which was present at concentrations reported as
acutely toxic to Daphnia up lex. Treatment plant personnel have observed gamma-
chloridane in results of organic chemical analyses performed subsequent to the
on -site evaluation. Methylene chloride was present at concentrations exceeding
1/100th the LC&a values reported for the compound though it does not appear to be
present at concentrations that would exert chronic toxicity in receiving stream
populations due to its extreme volatility and low acute toxicity_ Other organic
constituents were either below 1/100th their respective acute toxicity values.
had no available toxicity data, or were not individually identified by chemical
analyses. The absence of certain compounds in the influent that were detected in
the effluent (i.e. chlordene and diazinon) may indicate a source other than the
influent_ The digestor previously discussed in the toxicity testing section of
this paper could be a potential source of toxicants. The supernatant of this
digestor was being held and released at a very slow rate because facility opera-
tors felt that it contained a slug of highly toxic waste associated closely with
trickling filter upsets. The 48 hour Daphnia pulex bioassay of this sample
resulted in an LCso of 1.6%: a value much lower than any other acute test Der -
formed on-s'te. Even two influent samples, collected from., two separate mair,
-20-

influent trunks, and analyzed the week before on -site testing, resulted in LCao's
o1 14.4 and 13.6%, indicating that the digestor supernatant contained a substance
far more toxic to Daphnia up lex than influent samples. This result parallels the
facility's experience of only periodic upsets.
Acute toxicity associated with effluent tests can be attributed to the
individual or additive influences of copper, zinc, and diazinon. Additional
chronic toxicity of effluent samples to Ceriodaphnia dubia and Chempia parvula
may be the sum o1 impacts of the above as well as cyanide, chlordane, ammonia and
possibly methylene chloride or other organic compounds that were not individually
identified.
Chronic toxicity is predicted in the receiving stream by the Ceriodaphnia
168 hour LCao of 3.2%, and chronic value of 3.16% based on reproduction. A like
prediction is made for marine and estuarine organisms by the Champia parvula
chronic value of 3.53% based on reproductive success. As the waste is diluted by
the combined 7010 flows of the Cape Fear River and Northeast Cape Fear River
(1149 cfs) and the instreem waste concentration drops to approximately 1.1%, the
chronic toxicity predicted should abate.
-21-

RECOMMENDATIONS
1. The Wilmington North WWTP should continue performance of the 48 hr. Daphnis
up lex acute bioassays until the test has achieved the target level of >90%
for three consecutive months. Al such time the facility should begin quar-
terly Pass/Fail Ceriodaphnia survival and reproduction tests at a test con-
centration equal to the facility's instream waste concentration (IWC) of
30.69%. If this test is not successfully passed within two quarters, the
subject permit should be re -opened and toxicity limits incorporated as quar-
terly Ceriodaphnia survival and reproduction bioassays. The final chronic
value achieved as a toxicity limit should equal or exceed the facility's IWC
of 30.69%.
2. The facility should develop a written toxicity reduction plan with a sched-
ule of attaining comp-lience as will be set forth.
3. Due to effluent levels of copper, zinc, cyanide, diazinon, chlordane, and
methylene chloride encountered on -site, the sources of major contribution of
these should.be investigated and efforts made to minimize discharge, and thus
reduce observed acute toxicity. As concentrations of chlordane encountered
are predicted to approach the NC Water Quality Standard of 0.004 ppb during
7010 receiving stream conditions, the effluent level of this pesticide should
be closely monitored.
-22-

FOOTNOTES
' Peltier, W.H., and C.I. Weber. 1985. Methods for Measuring the Acute Toxicity
of Effluents to Freshwater Organisms. US EPA EMSL-Cincinnati, Ohio.
EPA/600/4-85/013.
° Geiger, D.L. et. al. 1985. Acute Toxicities of Organic Compounds to Fathead
Minnows (Pimeohales promelas) Vol. II. Center for Lake Superior Env. Studies.
Univ. Wis.-Superior.
° Blesinger, K.E. and G.M. Christensen. 1972. Effects of various metals on
survival, growth, reproduction, and metabolism on Daphnia megna. J. Fish Res.
Board. Con. 29:1691.
4 Mount, D.I., and T.J. Norberg. 1984. A seven-day life -cycle Cladoceran toxic-
ity test. Environ. Toxicol. Chem., 3:425-434.
6 Pickering, 0., W. Brungs, and M. Gast. 1977. Effect of exposure time and
copper concentration on reproduction of the fathead minnow (Pimeohales prome-
las. Water Res_, 11:1079-1083.
• Benoit, D.A. and G.W. Holcombe. 1978. Toxic effects of zinc on fathead min-
nows Pimeohales promelas in soft water. J. Fish Biol. 13:701-708.
7 Johnson, W.W., and M.T. Finley. 1980. Handbook of Acute Toxicity of Chemicals
to Fish and Aquatic Invertebrates. U.S. Dept. Inter., Fish Wildl. Serv.,
Resource Publ. 137. 98 pp.
° LeBlanc, G.A. 1984. Interspecies relationships in acute toxicity of chemicals
to aquatic organisms. Environ. Toxicol. Chem., 3:47-60.
° Sanders, H.O., and O.B. Cope. 1966. Toxicities of several pesticides to two
species of Cladocerans. Trans. Amer. Fish. Soc., 95(2):165-169.
1O Alexander, H.C_, et_ al. 1978. Toxicity of perchloroethylene, trichlorethy-
lene, 1,1,1-trichloroethane, and methylene chloride to fathead minnows. Bull.
Environ. Contam. Toxicol., 20:344-352.
" LeBlanc, G.A. 1980. Acute toxicity of priority pollutants to water flea
Daphnia magna). Bull. Environ, Contam. Toxicol., 24(5):684-691.
'• Pickering, O.H., and C. Henderson. 1966. Acute toxicity of some important
petrochemicals to fish. J. Water Poll. Con. Fed., 38(9):1419-1429.
" Sittig, Marshall. 1981. Handbook of Toxic and Hazardous Chemicals. Noyes
Pub., Park Ridge, N.J.
14 Lind, David T., L.L. Smith, S.J. Brodarius. 1977. Chronic effects of hydrogen
cyanide on the fathead minnow. J.W.P.C.F. Feb. 1977. 262-268.
i6 Thurston, Robert V., et al. 1986. Chronic toxicity of ammonia to fathead
minnows. Trans. Am. Fish. Soc., 115:196-207.
-23-

ra North Caroline Administrative Code Section: 15NCAC213.0200 classifications and
water quality standards applicable to surface waters of North Caroline, Feb.
1966.
—24—

APPENDIX
-25-

48 Hour Aaohnia pulex Screening Bioassay Appendix
Aquatic Toxicology Group
N. C. Division of Environmental Management
The Aquatic Toxicology Group performs 48 hour static bioassays using the
cladoceran Daphnia pulex to estimate the toxicity of waste discharge to aquatic life
in receiving streams. All test and sampling glassware and equipment are washed
with soap and hot water, then rinsed in nitric acid, acetone, and distilled/deionized
water, to remove all toxins and contaminants. Effluent samples are collected by
,DEM Regional Office or Aquatic Toxicology personnel. All samples are collected chilled
and above chlorination unless otherwise specified. Each sample is collected as a grab
or 24 hour composite using an automatic sampler and is sent chilled to the Aquatic
Toxicology Laboratory by state courier or bus. The sample must be received within
72 hours after collection.
The effluent samples are prepared for testing by being thouroughly mixed, adjusted
to standard test temperature, and aerated if dissolved oxygen is below 4O%
saturation. Hardness and alkalinity are measured. Chlorine is removed with
sodium thiosulfate if applicable. The effluent is then diluted with jL pulex culture
water, typically to seven concentrations (with replicates) from 0 to 909 effluent
and initial pH and DO are recorded.. Each test chamber receives 100 mis total
volume and ten D. pulex test organisms,0-24 hours old. The test is conducted in a 20
degree centigrade incubator with a 16:8 hour light:dark cycle. Mortality of the D.
pine!-is.,recorded after 48 hours, along with final pH, dissolved oxygen,and
temperature.
A 48 hour LC50, or concentration of effluent lethal to 50X of the test organisms in 48
hours, is calculated from the mortality data. An instream waste concentration
(IWC) for the effluent in the receiving stream is calculated using the treatment
system permitted flow and receiving stream 7010 flow. The LC50 and IWC are then
used to predict instream toxicity. If the effluent toxicity and/or the IWC are high, a
persistance bioassay may be conducted. This involves a second 48 hour static D
pulex bioassay on the same effluent sample after it has been exposed to light and
aeration for an additional 48 hours. If there is a 100% reduction in the LC50, the
effluent is considered to be non -persistent.
Guidance Document:1985. U.S. E. P. A. Methods for measuring the acute toxicity of
effluents to freshwater and marine organisms. Third Ed.(EPA/600/4-85/01S)
-26-

% Hour On -site Flowthrough Bioassay Appendix
Aquatic Toxicology Group
N. C. Division of Environmental Management
Candidacy for an on -site toxicity evaluation by the Aquatic Toxicology Group is
determined on the basis of acute toxicity of the effluent in comparison with
instream waste concentration. Acute toxicity is determined by a 48 hour screening
static bioassay .
For each on -site, flowthrough bioassay, a pre -test site inspection is performed in
order to:
1) Determine appropriate areas for physical placement of the mobile laboratory.
2) Acquire proper equipment and installation needed for electrical service.
3) Determine appropriate areas for effluent sampling and equipment needed for
such. Determine discharge schedule. Sampling is done above chlorination unless
otherwise specified.
4) Determine possible areas for dilution sampling (actual receiving waters or other
unstressed streams in the area) and equipment needed for such.
5) Collect additional samples of effluent and possible dilution waters for further
static Daphnis pulex acute and static renewal Ceriodaohnia dye reproduction
bioassays to determine the range of concentrations of effluent for the flowthrough
bioassay, to test for potential toxicity of possible dilution waters, and for fish
acclimation to the chosen dilution water.
6) Determine route suitability to the facility for the mobile laboratory(eg. low
clearances, poor road conditions).
7) Discuss.test procedures and requirements with appropriate facility personnel.
8) Determine appropriate sampling sites and techniques for benthic
macroinvertebrate surveys.
All test and sampling glassware and equipment are washed with soap and hot
water, then rinsed in nitric acid, acetone, and distilled/deionized water to remove
all toxins and contaminants.
Upon actual arrival on -site with the mobile laboratory, dilution water is obtained
and dilution and effluent pumping systems are set up and tested. Six to eight week
old fathead minnows are wet transferred to the test chambers (containing
approximately one liter of dilution water), ten fish .to a chamber. This transfer is
accomplished five fish at a time in a randomized order to each of the fourteen test
chambers until two randomized sets of five have been transferred to each
chamber. Seven concentrations (with replicates) including a control are used. The
second day on -site the dilutor and the dilution and effluent pumping systems are
turned on and the fathead minnow flowthrough bioassay is begun. A water bath is
utilized to bring the effluent and dilution water to a constant 20 degrees centigrade.
Test organisms are fed newly hatched brine shrimp twice daily throughout the
test.
A 7 day Ceriodaphnia dubia static renewal reproduction bioassay using newborn
organisms is begun the first day on -site. The organisms are transfered to fresh
dilution and effluent solutions daily and initial and final pH and dissolved oxygen
are recorded. The number of young born per organism per day is recorded and
mean cumulative reproduction is calculated for each concentration. The test is
-27-

conducted in a 25 degree centigrade incubator with 16 Iight:8 dark hour photoperiod.
Test organisms are fed 0.1 ml of a fermented trout chow mixture per organism per
day.
Individual chemical physical parameter meters are calibrated daily according to
DEM standards. At 15 minute intervals throughout the test, hydrolab systems
measure and record dissolved oxygen, pH, temperature, and specific conductance in
the test chambers with the highest and lowest concentration of effluent. These
systems are calibrated at test initiation, the mid -point of the test, and test
termination. Data from these systems is recovered daily and stored on floppy disc
and hard copy. Samples of dilution water, effluent at the bioassay sampling point,
final effluent, and the receiving stream upstream and downstream of the discharge
point are analyzed for hardness as feasible. Where applicable, daily residual
chlorine measurements will be made at the above sites.
During the on -site evaluation, Biological Monitoring Group personnel collect benthic
macroinvertebrate samples at the upstream, downstream, and dilution sites (see
Benthic Macroinvertebrate Survey appendix). where appropriate, electrofishing is
undertaken upstream and downstream of the discharge to obtain resident fish
population data. On a site -specific basis, various other efforts are undertaken, such
as monitoring dissolved oxygen levels in the receiving stream.
On a daily basis, test chamber screens are cleaned, effluent and dilution pumping
systems are checked and adjusted as necessary, and pH, dissolved oxygen, and fish
mortalities are recorded for each chamber. Dilution water is generally collected on
an alternating day basis, depending on need.
Two separate 24 hour composite samples of effluent are collected for chemical
- analysis by means of an automatic sampler. Receiving stream and dilution water
samples are also taken for chemical testing.
Static 48 hour Daphnia nulex bioassays are conducted on a 24 hour composite sample
of the effluent and a grab sample of the influent. persistence test aging is begun on
the effluent sample. Another static bioassay will be conducted after 96 hours of
aging to determine persistence of toxicity.
A tour of the facility is conducted. The actual treatment process is reviewed to
ascertain the quality of the operation of the treatment system and to determine the
treatment system's appropriateness to the type of waste being treated. An
inventory of any industrial contributors to a municipal waste treatment facility is
made. The manufacturing process at an industrial facility is reviewed to determine
the nature and composition of the waste. An Inventory of all chemicals used is
made.
A photographic record is made of the manufacturing and treatment facility,
sampling points, receiving stream, and sampling procedures.
At the end of the 96 hour test period, the dilutor is turned off and final mortality
observations are made. Breakdown and packing routines are performed and the
mobile laboratory is transported back to the Cary Aquatic Toxicology Laboratory.
The Ceriodaohnia dubia reproduction bioassay is continued at the lab until the 7th
test day. The persistance static bioassay is conducted.
awe

4
Several special care operating procedures should be mentioned. At facilities that
discharge for only a portion of the day, effluent samples are composited by the
dilutor system into a large reservoir on board the mobile laboratory for use as the
effluent while discharge is not in progress. If the effluent has a high oxygen
demand, aeration systems for the test chambers are utilized and dissolved oxygen
levels in the chambers are monitored closely in order to prevent levels from
dropping below 40% saturation at test temperatures. In the event that actual
receiving waters are deemed unfit for the test (i.e. potentially toxic), an alternate
source of dilution water is sought in the vicinity.
l
-29-

Ceriodaphnia Bahia Reproduction Bioassay Appendix
Aquatic Toxicology Group
N. C. Division of Environmental Management
The cladoceran Ceriodaohnia dubia is used as test organism in a 7 day static
renewal bioassay. This test estimates the effect of an effluent or other water
sample on reproductivity. A control and 8 concentrations of effluent ranging from
0.01X to 100R are used. There are 10 animals per concentration, each animal in a
one ounce polystyrene test chamber with 15 mis of solution. The test is conducted
in a 25 degree centigrade incubator with a 16 light/ 8 dark hour photoperiod.
All test and sampling glassware and equipment are washed with soap and hot
water, then rinsed in nitric acid, acetone, and distilled/deionized water, to remove
all toxins and contaminants. Effluent samples are collected by DEM Regional Office
or Aquatic Toxicology personnel. All samples are collected chilled and above
chlorination unless otherwise specified. Each sample is collected as a grab or 24
hour composite using an automatic sampler and is sent chilled to the Aquatic
Toxicology laboratory by state courier or bus. The sample must be received within
72 hours after collection.
The effluent samples are prepared for testing by being thouroughly mixed, adjusted
to standard test temperature, and aerated if dissolved oxygen is below 5 mg/l.
Hardness and alkalinity are measured. Chlorine is removed with sodium thiosulfate
if applicable.
The test is initiated with 20-24 hours old animals, or neonates. Adults having brood
sacs with eggs with visible eyespots (indicating eggs are about to be released) are
isolated and checked periodically. Neonates are removed and grouped according to
time of birth. Selected groups are then composited to make the youngest set of 90 or
more neonates born within a 4 hour period. The test is begun when the neonates
are introduced into the test chambers. Temperatures must be within 1 degrees
centigrade for transfer.
The animals are transferred daily to new test chambers containing freshly mixed
solutions. Chemical/physical parameters are measured twice for each batch of test
solutions. The initial value is taken before the animal is introduced and the final
value after the animal has been transferred out the next day. The animals are fed
daily. Each organism receives 0.1 ml of fermented trout chow -yeast -alfalfa food.
As reproduction begins, only the original test organism, now an adult, is
transferred to the new chamber. A drop of concentrated nitric acid is added to the
old chamber. This kills the young so they can be easily counted under a dissecting
microscope. A mean number of young produced per adult is calculated for each
concentration. Mortality of greater than 20% in control test organisms invalidates a
test.
Guidance Document: 1985.U.S.E.P.A.Methods for estimaing the chronic toxicity of
effluents and receiving waters to freshwater organisms. (EPA -600/4-85-014)
-30-

Benthic Macroinvertebrate Sampling Procedure Appendix
Biological Monitoring Group
N.C. Division of Environmental Management
The sampling methodology requires that a stream or river be wadable. High
water conditions may severely impair sampling efficiency by making critical
habitats inaccessable. A fixed number of samples are collected for each station.
These include: 2 kick samples of riffle and snag areas; 3 sweep net samples of
bank areas and macrophyte beds; and 2 fine -mesh washdown samples from
rocks, logs, leaves and substrate. The benthic macroinvertebrates are picked out
with forceps and preserved in alcohol. A collection card is filled out with such
data as canopy cover, substrate composition, stream morphology, dissolved
oxygen, pH, and stream temperature. Organisms are identified to the lowest
possible taxonomic level, generally to species. Density of each taxon is rated as
Rare (I or 2 individuals), Common (3 to 9), or Abundant (10 or more). Most
organisms may he identified using only a dissecting microscope, but Oligochaeta
and Chironomidae must be mounted and identified with a compound microscope.
Reference collections are maintained and all samples are retained and stored by
study area.
The first level of data analysis summarizes the data by total number of taxa or
"taxa richness" (S) and density (N) for each station. The second level of data
analysis summarizes the data by taxonomic groups (mostly orders of insects).
The EFT or intolerant (to pollution) taxa richness value is the sum of the taxa
richness values for the intolerant insect orders Ephemeroptera, Plectoptera, and
Trichoptera. The final step in data analysis is to summarize the data separately
for each taxa. The presence or absence of individuals of any tolerant species is, in
itself, insufficient for characterizing water quality. In a stream of good water
quality, both intolerant and tolerant species will be present. Tolerant species will
become dominant only in polluted systems when the intolerant species have been
eliminated.
A rating or "bioclassification' of overall water quality is assigned to a particular
site based on total and intolerant taxa richness values. Information on pollution
tolerance of any given taxon, combined with quantitative data on its distribution,
can often be related to specific chemical or physical changes in the environment.
-31-

List of Definitions
Aquatic Toxicology Group
N. C. Division of Environmental Management
Acclimation - refers to the process of gradually adjusting organisms from water of one
type to another so that the organisms are not stressed from radical changes in
temperature, hardness, pH, ionic strength, etc.
Acute toxicity - the effect a short term exposure to a chemical or substance has on an
organism; usually defined as death of that organism.
Application factor - a value which estimates an instream toxicant level that will be
safe at a chronic level for resident organisms from acute toxicity data, usually
defined by a fraction of the L%-
Aquatic - having to do with water.
Aquatic Toxicology Group - the group within the Biological services Unit (Water Quality
Section) which performs aquatic bioassays for the Division of Environmental
Management. The Group is located at the Cary laboratory facilities. All test
organisms (including Daphnia yule Ceriodaphnia =. and fathead minnows)
are cultured at these facilities by Aquatic Toxicology personnel.
Benthos/Benthic macroinvertebrates - a wide assemblage of invertebrate animals
(insects, crustaceans, molluscs, etc.) which live in streams, are an important
food source for fish populations, and are used as long term water quality
indicators.
Bioassay - a test used to determine the effects of a chemical or substance on an
organism.
Cadmium - one of the toxicants recommended by EPA for quality assurance testing of
the health of aquatic organisms.
Calibration - the adjustment of meters or systems with standards of known values in
order to assure the quality of data obtained from these meters or systems.
f&b2iaphnja IjL - a small cladooeran crustacean. It is found throughout most of North
America and obtains a maximum size of approximately 1 mm. This organism
has been adopted for aquatic bioassay testing because of its small size, ease of
culture under laboratory conditions, stability of genetic strains, and sensitivity
to toxic substances. It is generally used in a 7 day static renewal 'mini -chronic"
bioassay testing for mortality, time to sexual maturity and reproductive rate.
Cerlodanhnia 1P. is accepted in the field of aquatic toxicology for testing in
moderately soft waters.
-32-

Chronic toxicity - the effect of a chemical or substance on an organism, usually during
a longer period of time than that measured for acute toxicity. This effect is
usually measured as a non -fatal response (eg. reduction in growth, egg
production, predator avoidance, feeding rate, etc.). Tests for chronic toxicity
are frequently performed during the entire life cycle of the organism.
Chronic value(ChV): A numeric value representing the geometric mean of the numeric
values of concentrations analyzed as the No Oberserved Effect Concentration
(N.O.E.C.) and the lowest Oberserved Effect Concentration (L.O.E.C.) by chroic
toxicity testing. The chronic value is an estimate of the toxicant concentration
that will be the actual no effect concentration based on the chronic effect tested.
ChV=Antilog((Log1OL.O.E.C.+ Log1ON.O.E.C.)/2)
Composite - a sample or method of sampling used to obtain data on a substance which
may vary over time or space. For example, a time or temporal composite of a
stream would be one collected at intervals of time at the same location. This is
frequently accomplished with automatic sampling devices.
Danhnia pulex (water flea) - a small cladoceran crustacean. It is found throughout
most of North America and obtains a maximum size of approximately 3.5 mm.
This organism has been adopted for aquatic bioassay testing because of its small
size, ease of culture under laboratory conditions, stability of genetic strains, and
sensitivity to toxic substances. It is generally used in a 48 hour static bioassay
testing for mortality. p.Pulex Puleis widely accepted in the field of aquatic
toxicology for testing in moderately soft waters.
Design flaw - the volume of water and waste that is initially planned to pass through
a facility or waste treatment plant and still allow maximum operating
efficiency. Design flow is usually expressed in millions of gallons per day (mgd).
Dilution (water) - the water used in bioassay tests to dilute the waste water to
various concentrations (expressed as percent). Wherever possible, this water is
from the actual stream that receives the waste, upstream from that waste.
When this is not possible, other suitable water is obtained.
Dilutor - refers to a modified Mount and Brungs design serial dilution apparatus which
receives dilution water and effluent/waste and, through a series of chambers
and electrical solenoid valves, mixes the effluent and dilution into a series of
concentrations for the test (expressed as percentages of 100% effluent).
Electrofishing - method for collecting fish using electrical shock to momentarily stun
the fish so they float to the surface and are easily netted.
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Effluent— the -waste water-exiting-a-facility-which-it-dischargQdis treatadwasta to a
stream or as untreated waste to some other facility.
Fathead minnow (Pimenhelas promelas) - a small fish which occurs throughout much
of North America. It obtains a maximum size of approximately 100 mm and is
raised commercially as bait fish. The fathead minnow has been raised for
numerous generations in a number of laboratory cultures for use in toxicity
testing. The fish can produce eggs year round in the laboratory environment
under correct conditions, which provide test organisms as needed.
Flow -through - the flow -through bioassay utilizes a mechanical dilutor which either
continuously or occasionally replaces the effluent/toxicant concentrations
throughout the test in an attempt to simulate stream conditions where new
effluent and dilution water are continually flowing through an organism's
habitat.
Hydrolab; - a multiparameter instrument which measures and records temperature,
pH, dissolved oxygen, and specific conductance of water.
lnstream waste concentration (IWC) - the percent concentration of an effluent/toxicant
which is present in a stream under assumed worst case conditions. The IWC is
derived from the formula: [DF / (7Q10 t DF)] x 100 - IWC (X), where DF is the
design flow (in cis) of the facility in question and 7Q10 is the 10 year, 7 day,
low flow (in cfs) of the receiving stream.
LC50 - that concentration or percentage of a waste/chemical/substance which is lethal
to 50% of test organisms over a stated period of time
Lowest Observed Effect Concentration(L.O.E.C.)- The lowest concentration of toxicant to
which organisms are exposed in a life -cycle or partial life -cycle test, which
causes a statistically significant adverse effect on the observed
parameters (usually hatchability, survival, growth, and/or reproduction).
NPDES - National Pollutant Discharge Elimination System. A system devised by the
Federal Government and adopted by North Carolina for the permitting,
monitoring, and pollution abatement of dischargers to surface waters.
Neonate - roughly translated to newly born. In reference to Daphnia pulex• the
neonate refers to the life stage in the first and early second instar, generally the
first 24 hours of its life.
No Observed Effect Concentration (N. 0. E. C.)- The highest concentration of toxicant to
which organisms are exposed in a life -cycle or partial life -cycle test, which
causes no statistically significant adverse effect on the observed
parameters (usually hatchability, survival, growth, and/or reproduction.)
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Screening bioassay - a testing system established to determine general levels of acute
toxicity of compounds/discharges using 48 hour Daphnia Dulex tests.
7Q10 - the measurement of a stream's lowest average daily flow over a 7 day period
during a 10 year span, generally stated as flow in cubic feet per second (cfs).
Sodium pentachlorophenate - a chemical accepted by EPA as a toxicant for quality
assurance testing of the health of aquatic organisms. This chemical is an organic
pesticide.
Static - refers to an aquatic bioassay in which toxicant/effluent concentrations are set
up at the beginning of the test and not changed for the rest of the test. This test
is generally short term as compared to a flow -through or replacement test
because of potential degradation of the toxicant/effluent.
Taxa - refers to a group of genetically related organisms, (i. e. genus, order, species).
Taxa richness - number of taxa.
30Q2 - the measurement of a stream's lowest average daily flow over a 30 day period
during a 2 year span, generally stated as flow in cubic feet per second (cfs).
Toxicity - the adverse effect of a chemical/substance on an organism. Toxicity is
usually defined as a fatal or non -fatal response over a given period of time.
UT - Unnamed tributary - a term given to streams which have no accepted name.
*Use of this term or system does not constitute an endorsement
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