REPORT TO REGION X
ON THE RESULTS OF
THE SPOKANE RIVER ALGAL ASSAYS
hy
Joseph C. Greene, William E. Miller,
and Ellen Kerwin
NATIONAL EUTROPHICATION RESEARCH PROGRAM
Corva 11 is, Oregon
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INTRODUCTION
The Spokane River system is beset by three major water pollution
problems in the reach from Post Falls, Idaho to Long Lake Dam,
Washington. They are: 1) over-enrichment by plant nutrients, 2)
presence of toxic materials, and 3) low dissolved oxygen content.
Corrective water quality management practices have been initiated
by the Washington State Department of Ecology in cooperation with
the state of Idaho and Region X of the U. S. Environmental Protection
Agency to maintain and/or obtain Class A water quality standards
throughout the Spokane River System--below Post Fallsfor both dissolved
oxygen (8.0 mg/1) and total coliform content (median of 240--with 20
percent not to exceed 1000). This goal is to be met by upgrading the
City of Spokane's sewage treatment plant (STP) from primary to
secondary level treatment. While secondary treatment would enable
compliance with the Class A dissolved oxygen and total coliform criteria
it would not solve the nutrient over-enrichment problem which exists
downstream from the STP.
Assessment of the nutrient over-enrichment problem in the Spokane
River Basin is complicated by the occurrence of heavy metals (predominantly
zinc) in the upper reaches of the Coeur d' A.lene Lake watershed. Most
of the zinc entering, the Spokane drainage basin is from mining and
smeltering wastewater effluents or is leached from mine tailings. Zinc
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is found in the surface and ground waters confluent to the South
and to some extent the North Fork of Coeur d' Alene River. Proposed and
existing smelter wastewater treatment measures are currently being
upgraded and implemented by the Bunker Hill Mining Company in an effort
to solve the existing pollution problems.
The impact of the proposed municipal and industrial wastewater
treatment measures upon the growth of algae in the Spokane River
System has been under considerable debate.
At the request of Region X of EPA, algal assays were conducted on
seven Spokane River Basin samples by the National Eutrophication
Research Program at the Pacific Northwest Environmental Research
Laboratory, National Environmental Reseach Center, Corvallis, Oregon,
to determine the following: 1) the algistatic concentration of
zinc that would prevent the growth of planktonic algae, 2) the
nutritional--phosphorus and nitrogenstatus of the Spokane River System,
and 3) the critical nutrient responsible for the support of algal
growth within the Spokane River System.
METHODOLOGY
The "Algal Assay Procedure, (AAP) Bottle Test" August, 1971, using
Selenastrum capricornutum Prinz as the test alga, was used to assess the
algal growth response of the Spokane River samples. Prior to assaying
the Spokane River samples were autoclaved to solubilize the nutrients
tied up in the indigenous biomass, carbonated with a mixture of 1 percent
COg in air until the original pH was obtained, and filtered through a
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0.45y porosity membrane filter to remove particulate material which
would interfere with electronic particle measurement of algal biomass
in the inoculated test samples. Results of the algal assay are
reported as the maximum yield, in mg dry weight/1, of the test alga
obtained during a 14 day incubation period.
DISCUSSION AND RESULTS
The growth response of S_. capricornutum to known levels (0.0 to
186.0 yg/1) of available phosphorus with and without the addition of
selected concentration levels of zinc (20, 40 and 100 yg/1) was evaluated.
The results indicate that, in the presence of all other essential
nutrients, the addition of one yg ortho-P/1 will support 0.43 mg dry
weight/1 of test alga in waters containing > 10 yg P/l. A natural water
containing 15 yg P/l supported up to 6.4 mg dry weight/1 of S_.
capricornutum, providing sufficient nutrients other than phosphorus
were available in sufficient quantity.
Three levels of zinc (20, 40 and 100 yg/1 were added to AAP
culture medium containing varying amounts of phosphorus ranging from
10-186 yg P/l. In general, the algistatic effect of zinc decreased as
phosphorus content increased. Table 1 shows 20 yg Zn/1 to be algistatic
1n waters contining less than 10 yg P/l. Zinc concentrations of
40 and 100 yg/1 inhibited algal growth in waters containing 46 and 93
yg P/l respectively. Table 1 also shows the percentage of algal
growth inhibition of the three zinc concentration levels in waters
containing 10 to 186 yg P/l. Twenty yg Zn/1 decreased algal growth from
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Table 1, EFFECT OF ZINC UPON 14 DAY MAXIMUM YIELDS OF SELENA STRUM CAPRICORNUTUM
ug/1
14 Day*
Zinc Deptesslom (me dry weicht/1)
Phosphorus
Maximum
Percent
Percent
Percent
Content
Yield
20 ur/1
Inhibition
40 ur/1
Inhibition
100 ur/1
Inhibition
10
<0.10
<0.10
100
0.10
100
0.10
100
12
5.16
3.00
58
5.16
100
5.16
100
23
9.89
3.00
30
9.49
96
9.89
100
46
19.78
3.00
15
15.78
80
19.78
100
93
39.99
0.00**
0
8.99
22
39.99
100
186
79.98
0.00**
0
6.98
9
77.48
97
dry weight/1. **Thls concentration of zinc has been shown to be stimulatory*
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9.89 mg dry weight/1 to 6.89 mg dry weight/1 or 30 percent in waters
containing 23 yg P/l. These data indicate the sensitivity of S_.
capricornutum to phosphorus and zinc concentrations normally found
within the wcters of the Spokane River Basin. As a result, another
study was undertaken to define the problems of nutrient over-enrichment
and the presence of toxic materials in the Spokane River System.
Seven sampling sites (Figure 1) were chosen in the Spokane River
Basin which represented varying types of water quality with respect to
both nutrients and the presence of toxic materials. The South Fork
Coeur d' Alene River at Mullan, Idaho is a low nutrient high quality
water, uncontaminated by mine waste discharge. An autoclaved and
filtered, sample collected in Noveinber 1972, contained 7 yg
orthoDhosDhorus/1. 3 ua total soluble inorganic nitroaen/1 (NCL+NO.+NHJ
and 18 yg Zn/1. The orthophosphorus content indicated that, theoretically,
it would support algal growth in an amount not greater than 0.10 mg dry
weight/1 (Table 1). The actual algal yield in the sample was
0.03 mg dry weight/1 (Figure 2). The addition of 20 yg P/l to the sample
produced 0.31 mg dry weight/1 of S.. capricornutum. The predicted algal
yield for this phosphorus concentration (27 yg P/l) in the presence of
all other essential nutrients was 11.6 mg dry weight/1 of the test alga
(27 x 0.43). The failure of the test water to support this amount of
algal growth indicated that the South Fork of the Coeur d1 Alene River
may become limited by other essential nutrients when sufficient phosphorus
is added to the test water. The addition of 1000 yg N/1 and 20 yg P/l
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FIGURE 1. Identification of Sampling Sites for the Spokane River Basin Survey
ii So* Fork Cocur d* Alone at Mullan, Id,
2. So# Fork Coeur d* Alcne at
Smeltcrville, Idaho
3. Coeur d' Alene River at Lane, Id.
A. Coeur d' Alcnc Lake at Driftvood
Point, Idaho
5. Sookane River at Post Falls, Id.
6. r-okanc River at Seven Mi.le Road
Bridge, Washington
7. Snokane River at Long Lake Dam,
Vashinston
s
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FIGURE 2*
i t~t [ i i i [ i i i [ i i r~[ r~i i [ j j r
SOUTH "FORK COEUR d ALEiJE. RIVER at MULLAN, IDAHO
- Sample taken: November, 1972
Pretrsatment: Autoclaved-Filtered
i.es't.Alga: SeHenastrum capricornutum Prinz
CHEMICAL ANALYSIS.
Ortho P 0.007 mg/1
Dis.P 0.013 mg/1
Inorg. N 0.003 mg/1
Dis. Zinc 0.018 mg/1
y
SPIKE" y MAXIMUM YIELD
I
Control 0.03 mg/1
/ 1.00 mg/1 N 0.04 mg/1
0.02 mg/1 P 0.31 mg/1
N+P 8.19 jng/1
#
1
/
/
f /
./ /
f.
/
/ ~
/
4
I
/
«
/ /
/
/
~
~
. s?
K-^-fssr:^ -
I I ' I I I I I 'l J 1 1I' I I 1 I ill I I
0 4 8 12 16 20 24
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increased algal growth to 8.2 mg dry weight/1 or 71 percent of the expected
yield of 11.6 mg dry weight/1. This indicates that when the nitrogen and
phosphorus requirements for algal growth are satisfied either other
essential nutrients or the presence of toxic materials limits maximum
algal growth in the test water. A concentration of 20 yg Zn/1 added
to waters containing less than 20 yg P/l reduced the algal yield
approximately 3.0 mg dry weight/1 (Table 1). The actual yield of
8.2 mg dry weight/1 plus the 3.0 mg dry weight/1 lost due to zinc
toxicity was equal to 11.2 mg dry weight/1 or 97 percent of the expected
theoretical yield when nitrogen and phosphorus wen. added to the South
Fork Coeur d' Alene River water sample. This suggests that a concentration
level of 20 yg Zn/1 may inhibit planktonic algal growth in waters
containing less than 10 ug P/l.
The Coeur d' Alene Lake watershed is the main contributor of zinc
to the Spokane River, contributing about 83 percent of the total load
during September 1972 low flow conditions. Samples collected at the
South Fork of the Coeur d' Alene River at Smeltersyille, the Coeur
d' Alene River at Lane and Coeur d' Alene Lake (off Driftwood Point)
in November 1972 contained concentrations of dissolved zinc ranging
from 7500 yg/1 at Smeltersville to 118 yg/1 off Driftwood Point. The
algal assay growth responses (Figures 3, 4 and 5) of these waters
reflects the toxicity of zinc upon the growth of S_. capricornutum.
Each of these autoclaved and filtered test waters supported less than
0.10 mg dry weight/1 of the test alga. This growth response was
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Figure 3
i ' i 1 I ' I I « I ' | » i
SOUTH FORK COEUR d' ALENE RIVER at SMELTERVILLE, IOAHO J
Sample taken:. November, 1972
Pretreatment: Autoclaved-Fi1tered
.Test Alga: Selenastrunt capri corriu turn Prinz
CHEMICAL ANALYSIS
Ortho P 0.096 mg/1
Dis. P . M
Inorg. .N 0.918 mg/1
Dis. Zinc 7.500 ma/1
SPIKE MAXIMUM YIELD
Control 0.02 mg/1
t
Vw*
C
l.OOmg/l^N 0,01 mg/1
0.02 mg/V P 0.01 mg/1
N+P ' O.Ot mg/1
D
. *.
J t f i1IL.C..I. f< ~
i 3 5 7.8 (0 12 ' 14 Q
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\
CHEMICAL ANALYSIS
Ortho P ' 0.004 mg/1
Dis. P 0.008 mg/1
Inorg. N 0.175 mg/1
Dis. Zinc 2.470 mg/1
SPIKE MAXIMUM YIELD
I*
K
>-
Q£
Q
N+R- 0..02 mg/1
I .1 t * . I I 1 I 1 | * i32
COEUR d" ALENE RIVER at LANE, IDAHO ~ ^
Sample taken: November, 1972
"Yetreatment: Autoclaved-Filtered
Test Alga: Selenastrum capricornutum Prinz
O
o
Control .. 0.03 mg/1 O
^ b I-00 mg/1 N 0.03 mg/1
^ n 0.02 mg/1 P 0.03 mg/1
"""~{ *1
3
(
>
ft"
4».fL
til i i i i \s'\ " I
5- 7.8 {O (2 14
w
r> n\jfn»
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I ~ 1 i i r I 1 i J-T-T
,COEUR'd' ALEHE LAKE at DRIFTWOOD POINT, IDAHO
Sample taken: .November, 1972
Pretreatment: ' Autoclaved-Filtercd
Test Alga: Selenastruni caprlcornutum Prinz
-J
CHEMICAL ANALYSIS
I - Ortho P
0.002 mg/1
u: Dis. P 0.008 mg/1
v. j Inorg. N 0.001. mg/1
^ _ Dis. Zinc 0.118 mg/1
or .
O Jr* SPIKE MAXIMUM YIELD
Control. 0-03 mg/1
1.00 mg/-l N 0.04 mg/1
0.02 mg/1 P 0.04 mg/l
N+P Q.05 mg/1
I I I'' til I I I I t I [ I
o 5 7.Q to 12 14
n&Y
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within the anticipated yield based on the orthophosphorus content in the
samples collected at the Coeur d* Alene River at Lane and at Coeur d1
Alene Lake (off Driftwood Point). The South Fork of the Coeur d' Alene
River sample collected at Smeltersvilie contained 96 ug P/l. This
concentration of phosphorus, in the presence of all other essential
nutrients and in the absence of toxic materials should have supported
41.3 mg dry weight/1 of S. capricornutum. Miller, Maloney and Greene,
1973 reported the following classification index, based on the 14
day maximum yield (mg dry weight/1) of S^. capri cornutum obtained in
49 autoclaved and filtered lake water samples..
The theoretical (96 x 0.43} 41.3 mg dry weight/1 maximum yield
calculated for the South Fork of the Coeur d* Alene River at
Smeltersville indicates that this water could have a high phytoplankton
growth potential if its zinc content of 7500 yg Zn/1 was reduced below
the algistatic level. An abundance of periphytic algal growth was
observed in the river during the November, 1972, sampling. This
suggests that periphyton may have a greater tolerance to high
concentrations of zinc than phytoplankton.
ALGAL PRODUCTIVITY CLASSIFICATION DAY 14 MAXIMUM YIELD
Low Productivity
Moderate Productivity
Moderately High Productivity
High Productivity
0.00 to 0.10
0.11 to 0.80
0.81 to 6.00
>6.00
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u
\
i
q:-
q
¦ Figure 6
¦ I ' I 1 . I. » I i. ' I 1 I ' I Jg
SPOKANE RIVER at POST FALLS, IDAHO
Sample taken: November, 1972 .
f?re treatment: Autoclaved-Filtered
Test Alga: Selenastrum capricornutum Prinz
O
o
' CHEMICAL ANALYSIS
Ortho P- ' 0:008 .mg/1
Dis. P 0.021 mg/1
Ino.rg. N- 0-001 mg/1
Dis. Zinc 0.10~ mg/1
SPIKE: MAXIMUM-YIELD
Control 0.07.-mg/1'
l.OO.mg'/l N^. 0.03 mg/1
0.02 mg/1. Pv- 0.04.;mg/l
N+P 0.03 mg/T
r
C ¦>
i
> < mmm *
S
i
r
X - ^ f. . ,
o
I » T ' I ' 1 1 » I i I ¦ I ^
I 3 5 7.8 {O 12 14
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The autoclaved and filtered (November, 1972) water sample collected
from the Spokane River at Post Falls contained 8 yg P/l, 1 yg total
soluble inorganic nitrogen/1 and 107 yg Zn/1. The nitrogen and
phosphorus nutrient content of this water is essentially the same as
that found in the autoclaved and filtered Coeur d' Alene Lake (off
Driftwood Point) water sample. Water collected at both sampling sites
exhibited similar algal growth response to the addition of nitrogen
and phosphorus (Figures 5 and 6). The average dissolved zinc (112 yg/1)
in these water samples would mask the effect of additional phosphorus
loading, up to 25 times (200 yg P/l) greater than that presently found,
upon the growth of planktonic algae. Dissolved zinc concentrations of
96 yg/1 within waters containing up to 186 yg P/l have been shown to be
algistatic (Greene and Miller, 1973). This suggests that zinc toxicity
may be the predominate growth limiting factor for planktonic algae in
the Spokane River between Post Falls and Nine Mile Bridge.
The Spokane River samples collected at Riverside State Park and
Seven Mile Road bridge reflect the nutrient loading of the City of
Spokane's sewage treatment plant (STP). The Spokane STP is the major
contributor of phosphorus to the Spokane River. Cunningham and Pine
(1969) cite an increase from 265 kg orthophosphorus/day (120 lb/day)
in the upstream water to 6836 kg/day (3100 lb/day) immediately downstream
from the STP. This is approximately a 26-fold increase of orthophosphorus
in the receiving water. In September 1972 the Spokane STP contributed 57
percent of the total phosphorus loading to the Spokane River (EPA Region X
Report, Feb., 1973). The maximum 14 day algal yield obtained in the
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November 1972 autoclaved and filtered Spokane River at Seven Mile Road
Bridge water sample was 0.11 mg dry weight/1 of S_. capricornutum (Figure 7).
This was 0.3 percent of the theoretical yield of 36.6 mg dry weight/1
that could be supported by 85 yg P/l. The predicted yield for this
phosphorus level is valid when either no toxicant is present in the water
or when other nutrients are not growth limiting. The November 1972
Seven Mile Road Bridge sample contained 46 yg/1 of dissolved zinc. This
level of zinc could limit algal growth greater than 95 percent in a water
sample containing 85 yg P/T- Figure 8 shows the effect of removing the
46 yg Zn/1 from the Seven Mile Road Bridge Sample (by cation exchange)
upon the growth of the test alga. The algal growth yield on this treated
Sample was increased to 15.4 mg dry weight/1 and represented an
approximate 160-fold increase in algal growth. Adding 40 and 100 yg Zn/1
back to the metal stripped sample again inhibited algal growth. This
reinforces the hypothesis that "upstream zinc levels mask the nutritional
impact of the City of Spokane STP phosphorus loading to the Spokane
River upon the growth of planktonic algae." Natural degradation and/or
complexing of zinc by organic compounds reduced the concentration of zinc,
which was greater than 100 yg Zn/1 immediately downstream from the STP
to less than 20 yg Zn/1 in the November 1972 Long Lake Dam water sample.
The effect of reduced zinc concentration in the water at Long Lake
Dam upon the growth of S_. capricornutum in the autoclaved and filtered
samples collected in Movember 1972 is shown in Figure 9. The maximum
yield obtained in this sample was 14.9 mg dry weight/1. The theoretical
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I ' I. 1 I'll' I I ' I
SPOKANE RIVER at SEVEN HUE ROAD BRIDGE,. WASHINGTON" - ^ ~
Sample taken: November, 1972
J
w~..,r.w , "~J
Pretreatment: Autoclaved-Filtered J'
Test Alga: Selenastrum capricornutum Prinz J
-J
2
I
"H
*«»
o:
Q
CHEMICAL ANALYSIS
Ortho P 0.085 mq/'l
Dis.. P 0.082 mg/1
Irforg. N 0.649 mg/1
Dis.. Zinc 0.046 mg/1.
SPIKE MAXIMUM YIELD
Control 0.11 mg/1
'."1.00 mg/1 N 0.06 mg/1
' 0.02 mg/1 P 0.05 mg/1
.N+P 0.05 mg/1
v su.s-ii'e1'-:
I I III ill I 1 I i I I
I 3 5 7 S 10 12 ' .14
c
_.C
1
y i
-3 ti
q
i
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o
o
F~r-r~T-
T
t r
I
~i j r
T
i i r
JJl" I | iii~q
SFCKAKE RIVER et-SEVEN.WILE ROAD BRIDGE, WAS HI KG TON'
Sercrrlc taken: November, 1972
Pretreotrccnt: ' Autoclaved-FiIfcered
Test Alga: . Selenastrure CR^ricornotum Prin?
SPIKE
Control.
7-?etal Removed
MAXIKUjjJOELD
0+152 g/l
T57J57 trg/1
+ '0.040 »..*/! Zn
+ 0,100 nip/1 Zn
CHEMICAL' ANALYSTS .
Ortho P
Bis. P
A4IV*5« I*
0.031 TTlg/1
0.02Z ng/l
<5 .Li
" Q
0.035 trig/1
0.082 rcg/1
0.049 nj{i/1
0.046 n»g/l
3'
1 L
J L
¦ f~' ¦
I L
I_L
.1 L
&
8
12
nvc
15
2;
94
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Figure 9
-J
§
i
g:
cj
i ' l * I 1 I 1 » I ' i > 1
SPOKANE RIVER at LONG LAKE DAM, WASHINGTON
Sample taken: November, 1972
Pretreatment: Autoclaved-Filtered ,J
Test alga: Selenastrum capricornuturn Prinz
CHEMICAL ANALYSIS _
"Ortho P (Q.046 mgTTA'
Dis. P 6.044 mg/T
Inorg. N 0.563 mg/1
Djs. Zi nc... xO-.OQ9*mg7T^
->X*
&
/'.V
/
/ '
/ /
"/'
/ //
/{/.* SPIKE .MAXimXIELD
//.* Control CJ4.89 mg/1
«'/ - * 1.00 mg/1 N TO.bb rng/1
jtlj 0.02 mg/1 P 7.11 mg/1
.- // - N+.P 8.99 mq/1
V
/
r
i ¦ i i i i i I l ii i i . f
l 3 5 7.8 (Q, 12 {4
~d
. .7
i
3
. / /> / 3
/ t
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yield, based on the orthophosphorus content of 46 yg P/l, is 19.8 mg dry
weight/1. The lower than anticipated growth response to the addition
of nitrogen and phosphorus indicates that either some essential nutrient
other than phosphorus, may be limiting maximum algal growth or that a
toxic substance, other than zinc, may be present in this water. However,
a growth response of 14.9 mg dry weight/1 of S_. capricornutum in the
algal assay indicates that Long Lake Dam is a highly productive body of
water.
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SUMMARY AND CONCLUSIONS
(1) Assessment of the nutrient enrichment problem in the Spokane
River Basin is complicated by the occurrence of heavy metals
(predominantly zinc) in the upper reaches of the Coeur d* Alene Lake
watershed.
(2) The Coeur d' Alene Lake watershed is the main contributor of
zinc to the Spokane River, contributing about 83 percent of the zinc load
during September 1972 low flow conditions.
(3) Twenty yg zinc/1 is algistatic for the growth of planktonic
algae in waters containing less than 10 yg P/l.
(4) The city of Spokane's sewage treatment plant is the main
contributor of phosphorus to the Spokane River, contributing 57 percent
during September 1972 low flow conditions.
(5) The average dissolved zinc concentration of 112 yg/1 in the
Spokane River from Post Falls, Idaho to Riverside State Park, Washington
would mask the effect of the addition of 200 yg P/l to these waters
upon the growth of planktonic algae.
(6) The natural degradation of zinc from 100 yg/1 to 20 yg/1
downstream from the Spokane sewage treatment plant to Long Lake Dam
enabled algal growth to increase proportionally to the orthophosphorus
content of the water.
(7) Forty yg Zinc/1 is 100 percent inhibitory (algicidal) in waters
containing 20 yg P/l; 22 percent inhibitory (algistatic) in waters
containing 93 yg P/l; and 9 percent inhibitory to planktonic algal
growth in waters containing 186 yg P/l.
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(8) Because of the high contribution of phosphorus from the City
of Spokane's sewage treatment plant, it would be expected that eutrophi-
cation problems would result if the zinc content of the water was lowered
considerably.
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