ML20033A187
| ML20033A187 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/30/1980 |
| From: | NORMANDEAU ASSOCIATES, INC. |
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| XI-4, NUDOCS 8111240866 | |
| Download: ML20033A187 (15) | |
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l
,A EFFECTS OF SEABROOK STATION"S SETTLING BASIN EFFLUENT ON SURVIVAL OF SELECTED MARINE INVERTEBRATES TECHNICAL REPORT XI - 4 SEABROOK ECOLOGICAL STUDIES, 1979 Prepared for:
PUBLIC SERVICE COMPANY Manchester, New Hampshire by l
NORf1ANDEAU ASSOCIATES, INC.
l 25 Nashua Road Bedford, New Hampshire i
l I
June 1980 0111240866 811118 PDR ADOCH 05000443 C
PDR a
TABLE OF CONTENTS PAGE
1.0 INTRODUCTION
1 2.0 liETH0DS AND MATERIALS....................
2 2.1 In SITU BI0 ASSAY..
2 2.2 IN Vivo BI0 ASSAY.................... 4 2.3 STATISTICAL ANALYSIS..................
6 3.0 RESULTS...........................
6 3.1 IN SITU BI0 ASSAY..
6 3.2 IN Vivo BI0 ASSAY.................... 8 4.0 DISCUSSION......................... 8 5.0
SUMMARY
11 6.0 LITERATURE CITED.....................
13 l
i
LIST OF FIGURES PAGE 1.
Location of control sites for in-situ bioassays.......
3 2.
Flow schematic in-vivo bioassays.
Seabrook Settling Pond Drain Bioassay.....................
5 LIST OF TABLES 1.
SubHARY OF AUGUST 1979 IN-SITU BI0 ASSAY RESULTS....... 7 2.
SUFNARY OF JANUARY 1980 IN-VIYO BI0 ASSAY RESULTS...... 9
)
11 J
l EFFECTS OF SEABROOK STATION'S SETTLING BASIN EFFLUENT ON SURVIVAL OF SELECTED ftARINE INVERTEBRATES, SEABROOK ECOLOGICAL STUDIES, 1979
1.0 INTRODUCTION
In August, Septe=ber and November, 1978, a series of site specific bicassay experiments were conducted (NAI 1979)-to determine in situ the acute (7 day) effects of effluent discharged into the Browns River from a one-acre settling pond on the Seabrook Station construction site. The pond includes surface tunoff, tunnel drainage and a relatively small quantity of treated sanitary waste. Tests were run to evaluate the discharge effects on the sand worm, Nereis virens, the sand shrimp, Crangon septemspinosa, and the sof t-she11 clam, Mya arenaria. Field experiments were repeated in' August 1979 and a laboratory assay conducted in January 1980 for the purpose of confirming or rejecting initial findings, and evaluating the impact of increased flow from the pond; 0.2 million gallons per day (MGD) in 1978, to 0.9 MGD in-1979 and to 2.2 MGD in 1980. Assays were also modified to provide longer exposure times for Mya arenaria and to evaluate the effect of suspended solids.
Informatien provided from these bioassay tests is limited to whether or not environmeatal conditions at test sites in question will sustain the test organisms for the test period. While a negative find--
ing (no significant mortality) indicates absence of harmful conditions at the test site during the test period, a positive finding (significant mortality) signals the presence of harmful substance (s), but does not implicate a specific source of environmental t sturbance.
1
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2 2.0 METHODS AND MATERIALS 2.1 IN SITU BI0 ASSAY Procedures employed in the August 1979 bioassay were idencical to those used in the 1978 studias (NAI 1979). Adult Crangon septemspinosa and juvenile Nya arenaria (shell length 25 to 30 mm) were collected in the lcwer Hampton-Seabrook Estuary within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of each test.
Nereis virens were obtained from a local bait dealer, healthy specimens were selected by demonstrating an ability to establish burrows in sand.
Test containers were plastic pt.
s, 25 x 30 x 13 cm, filled to a depth of 8 cm with sand (grain size.05 to.5 mm).
The pans were set in wooden frames, with 3 pans for each species, and covered with 1.6 mm mesh plastic screening held in place by a rubber band passed around the circumference of the pan.
Cn 23 July 1979, frames containing pans with animals in place were set out below MLW in Hampton Harbor. The next day the pans were checked for dead animals before being taken to the test sites.
In Browns River, test sites were immediately above and below the settling pond outfall (Figure 1).
A new reference or " control" site was located on Mill Creek (Figure 1) which appeared to match environmental conditions (temperature, salinity, D.O.) in Browns Rivar more closely than the Hampton River tributary used in 1978 (cf. Table 1, NAI 1979).
After securing the test frames to the stream bottom at the test sites, water samples were taken daily at low tide and approximately every other day at high tider samples were analyred for dissolved oxygen concentration, salinity, and turbidity. Water temperature was measured over the f rames at the same time as water samples were being taken.
During the test period, screening covering the pans was checked for build up of sediment or detritus and brushed clean as needed. After seven days, test frames were hauled out and N. virens and C. septemspinosa recovered frem the pans by passing the sand through a 6 mm mesh sieve. The
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Location of control sites for in-sica bioassays.
Seabrook Ecological Studies, 1979.
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4 The number of live organisms were. then counted and these counts compared against original live counts to' determine the total nmnber of dead and missing.'Atter an additional seven days, M. arenaria were. recovered and data recorded as above.
2.2 IN 7770 BI0 ASSAY Procedures used in the January 1980 in vivo bioas'say followed -
protocol outlined in "Metho<ls for measuring the acute toxicity of effluents
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to.quatic organisms" (USEPA, 1978).
Settling pond effluent was pumped from approximately 1 meter below the surface of the settling pond at the discharge weir into a 1000 gallon holding tank. Water for the control assays was pumped from the Browns - River approximately 100 downstream of the discharge to a 500 gallon holding tank. Water was collected during the last hour of the flooding tide. Water in both primary holding tanks was replenished-on a daily basis. Effluent and (control) water were fed through a series of secondary holding tanks, heat exchangers and filters (20 micron) to a distribution system to provide filtered and unfiltered effluent, and unfiltered control water at a constant volume (5 liters / hour) and tempera-ture (20*C) (Figure 2).
Test chambers were 19-liter 30 cm x 20 cm x 25 cm-deep glass aquaria filled to a depth of 6 cm with fine sand. Five replicate aquaria were used with each treatment.
Test organisms used in the assay were Nerels virens (5-10 cm),
Crangon septemspinosa (2-3 cm), and Nya arenaria (2-3 cm).
Ten representa-tives of each species were used in each replicate. Test organisms were l
from laboratory stocks, maintained in the laboratory for approximately 10 weeks prior to the start of the assay. Nya arenarla and C. septem-spinosa were originally collected from the Hampton/Seabrook estuary j
while N. virens were obtained from a local commercial supply house. During the holding period the M. arenaria and N.
virens were maintained at 15*C, while C. septenspinosa were kept at ambient temperature (2-10*C).
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6 animals were acclimitized to the 20*C test temperatures over a period of 5 days (l*C increase per day for M. arenaria and N.
viren.', 3-4*C increase-per day for C. septeaspinosa). Animals were placed in the aquaria 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to the start of the assay, dead animals or those showing obvicus (behaviot al) signs of stress were removed and replaced.
Measurer.ents of water temperature, and salinity were made on a daily basis. Dissolved oxygen and pH measurements sere measured at the start of the experin<nt and on days 7 and 14.
Test animals were ob-served daily, numbers of animals alive (for Nya and Crangan) were re-corded and dead animals re=oved.
2.3 STATISTICAL ANALYSIS Ccunts of live versus dead (or missing) test organisms in experiments where centrol survival exceeded 90%, were submitted to a 3-factor G-test (Sokal and Rohlf,1969). This test computed expected chi-square frequency distributions for: 1) conditien (live or dead); 2) test site; and 3) replicates, plus tested the independence of the three factors from one another. of primary concern was comparison of condition j
with test site or effluent type; finding a significant " dependency" j
between these ;wo factors would mean that organism deaths were affected by sample site er treatment.
3.0 RESULTS i
t 3.1
.In Sita Bioassay Results of the in-situ bicassay, summarized in Table 1, show l
significant dependency between mortality and test site for nereis virens; that is, significant difference in rurvival existed between the reference l
and treatment sites as well as between treatment sites. Data for Nya arenaria showed no significant dependencies related to test site or i
l t
l TABLE 1.
SUMMARY
OF AUGUST 1979 TN-SITU BI0 ASSAY RESilLTS. SEABROOK ECOLOGICAL STUDIES, 1979.
RANGC Of RANGL OF RANGE Of RANGE Of NO. S*HVIV0RS J
TEMPERATURE (*C)
SALINITY (%)
DISSOLVED OXYGEN (mg/1)
TURBIDITY (NTU)
(MAX. NO.
- 20) gp37;g Of BROWNS MILL BROWNS Mitt BRvWNS MILL BROWNS M!t t ABOVE BELOW Mitt G-TEST SPECIES TEST RIVER CREEK RIVER CREEK RIVER CREEK RIVER CREEK REP DISCHARGE DISCHARGE CRIEK RESULTS Nereis virens 7 days terw 20.3 20.5 15.0 15.5 4.H 4.7 1.1 0.4 1
la 6
18 3 facte,r
- Hi ah 2fa.4 27.6 29.7 31.4 12.4 9.7 6.6 4.4 2
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1 15 5
20
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(Same as for #ereas virens)
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O' 15 12 n..e.
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14 15 17 Mva arenaria 14 days law IP 16.3 15.0 15.5 4.H 47 1.1 0.4 1
20 20 20 3 factor' High 28.7 27.8 2's.9 31.4 12.4 9.7 8.3 4.4 2
20 20 19 n.s.
I 20 20 19
- Test results significant at a =.005 for atation m>rtaIity depe ndency n.s.
Test resulta not significant at e =.05 n.a.
Resulta not statistically analyzed due to survival at reference field ovntrol site <90s b
hesults suspect as tray was turned upelJe down before recovery, gossibly crushing the organisms, a
contition a site a replicate
8 replicate. Results of the Crangon septemspinosa assays were considered:
to be inconclusive as mortality in the control samples exceeded 101h and therefore were not analyzed statistically.
3.2 In-trivo Bioassay In-vivo bioassay results summarized in Table 2, show no signi-ficant dependency between mortality and treatments (filtered and unfiltered effluent) or between replicates for either N. arenarla or N. virens.
Results of the assay with C. septemspinosa show both the unfiltered and filtered effluent having greater mortality than the controls. These.
results were not tested statistically, however, and do not carry the same weight as those for N. arenarla and N. virens, as control mortalities exceeded los suggesting other sources of stress.
4.0-DISoUSSION In-situ and in-vivo bioassays evaluating the potential acute toxicity of effluent discharged from the Seabrock Station settling pond produced similar findings for M. arenaria and C. septemspinosa while
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results of the N. virens assays appeared to be ambiguous.
In both field and laboratory assays M. arenaria showed no gross response (i.e. death) to the settling pond effluents. High survival rates for M. arenaria in the 1978 field bioassays had been attributed to the animals ability to respire anerobically for extended periods and reduce or eliminate contact with the effluent. During the in-vivo assays at 20*C, clams actively filtered (siphoned) water, exposing themselves to any potential toxicants and indicating that + ae effluent had no acute adverse impacts. The possibility of physiological impacts such as bicaccumulation, changes in condition indices or reproductive potential,
'was not addressed.
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TABLE 2.
SUMMARY
OF JANUARY 1980 IN-Vivo BI0 ASSAY RESULTS. SEABROOK ECOLOGICAL STUDIES, 1979.
t DURATION NUMBER OF SURVIV0RS AT END OF ASSAY OF TEMP SAL D.O.
SPECIES UNFILTERED FILTERED CONTROL G-TEST TEST
- C ng/l pH REP EFFLUENT EFFLUENT RESULTS c Mya 14 days 20*11*C d*=24.5-8.0-7.0-1 105 10 8
N.S'.
arenaria 27.2 8.8 7.5 2
10 10 8
C =27.0-8.0-7.0-3 10 9
10 30.1 8.3 7.5 4
10 10 10 5
10 10 10 Nereis 7 days 20*il*C E =24.5-3.0-7.0-1 10 9
10 N.S.
l virens 27.0 8.8 7.5 2
9 7
10 C =27.0-8.0-7.0-3 9
9 10 30.1 8.8 7.5 4
8 9
10 S
1C 9
9-l Crangon 7 days 20* 1*C E =24.5-
-8.0-7.0-1 2
2 1
N.A.
septomspinosa 27.0 8.8 7.5
-2 0
3 6
g C =27.0-8.0-7.0-3 2
3 2
30.1 8.8 7.5-4 2
2 6
5 1
1 6
a E = Settling Pond Ef fluent C = Browns River Control Number of animals at start of experiment = 10 in all experiments N. A. = Results not analyzed due to control survival <90%;
indicates potential external stress on the test animals N.S. = significant-at a =.05, t
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7 10 Treatment mortality was observed for C. septemspinosa in both field and laboratory bioassays. However in both se*J of bicassays survival in control (or reference) experiments was below the criterion (90%) for a successfully concluded bioassay test.
Observations made
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during the field assay suggested that canabalism might have been a factor in reducing overall survival; although this was not documented.
In the laboratory assay no incidences of cannibalism or aggression were noted, meaning that some factor other than cannibalism produced the high mortality in the in vivo tests. Potential sources of stress include the rate of temperature change (3-4'C/ day) during acclimitization and the reference (control) water used in the experiment. While the rate of temperature change is higher than the l'C / day generally used in accli-mitizing laboratory stocks, it is within the range experienced by field populations during migrations (Boddeke, 1976). Results suggest that either there is an experimental handling problem with these organisms or that the condition of the estuarine river water ured as controls is not of adequate quality for high survival of Crangon. These problems will have to be resolved before the effects of the settling pond water on this species can be determined.
Field and laboratory assays with N. virens showed some apparent discrepancy in survival rates; field assays showing 'gnificant treatment mortality while laboratory assays showed no significant difference in s.2 rival between control and treatments. While no significant treatment related mortality was observed in laboratory tests, differences in the physical condition of the animals did exist between controls and treat-ments. Nerefs virens recovered from the controls were active and had firm bodies while those recovered from the treatments, both filtered and unfiltered effluent, were sluggish and flaccid.
In evaluating the two sets of data (field vs. laboratory) differences in survival of Nerels can possibly be attributed to the synergistic effects of the effluent and the different temperature regimes.
e 11 Analysis of the filtered and unfiltered effluent showed no significantly different rates of survival for all animals tested. While the assay procedure was designed to remove particulate matter, larger than <20 microns, it was estimated that much of the suspended material being discharged during the assay was in the fine silt / clay size range, less than 5 microns.
5.0
SUMMARY
Both field (in-situ) and laboratory (in-vivo) experiments showed generally similar results with respect to the effects or Seabrook Station's settling pond effluent on selected benthic invertebrates. The sof t-shell clam, Mya arenaria, survived with no significant mortalities for the maximum test period (14 days) and were observed to be actively filtering in the laboratory tests. The sand worm, Nerels virens, showed greater sensitivity. Significant mortalities occurred in the effluent in field experiments at a water temperature of about 25'C while in the laboratory controlled experiments no significant mortalities were noted. In-vivo experiments were run at 20*C, however, and the physical condition of N. virens were noticeably poorer in the effluent water.
Test results on the sand shrimp, Crangon septemspinosa, were inconclusive since significant mortality in control tests indicated sources of stress other than experimental; these organisms did appear to be more sensitive than the other two species tested.
Tests results should be considered in light of experimental restrictions. In the field tests, organisms were limited to a confined area and substrate depth and thus could not escape any natural or un-natural environmental conditions by further burrowing or movement; also it was not possible to precisely match conditions at the control site with those at the effluent site. As opposed to field tests, laboratory assays were run with no dilution of the effluent and with no simulation of fluctuating tidal conditions (temperature, salinity, dissolved oxygen),
thus simulating a " worst-case" situation. Given these conditions, test resuits from both these experiments were judged similar.
12 6.0 LITERATURE CITED 1
I Boddeke, R.
1976. The seasonal migration of the brown shrinp Crangon crangen. Neth. Jour. Sea Res. 10:103-130.
Normandeau Asssociates, Inc.
1979. Effects of settling pond effluent on survival of selected marine invertebrates: In-situ Bioassay.
Prepared for Public Service Company of New Hampshire. 8 pp.
Soka., R.R. and F.J.Rolf.
1969. Biometry W.H. Freeman Co., San d'rancisco. 776pp.
U.S. Environmental Protection Agency. 1978. Methods for measuring the acute toxicity of effluents to aquatic organisms. EPA-600/4-78-012 U.S. EPA Cincinnati, OH 51 pages.
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