wafer t:rh' v · coliform bacteria (35°) and total bacterial counts per 100 m1 of water 12...

BACTERIAL POLLUTION OF KANEOHE BAY, OAHU

(June through August 1967)

by

K. R. Gundersen

and

D. B. Stroupe*

Technical Report No. 12

December 1967

Project Completion Report

for

A STUDY OF THE BACTERIAL POLLUTION OF

KANEOHE BAY, OAHU

Contract 9519 with State Department of Health

*PHS trainee, Grant No. 5TOI AI00243-05

Wafer ltesourees ~seardi ~enre,2525 Correa Road t:rh'University o f Hcwoil VHonolulu, Hawa ii 96822

ABSTRACT

From June through August 1967" a thorough investigation was made

of the presenae and numbers of aoliform baateria" feaal streptoaoaai

(enteroaoaai)" and baateria aapable of growing on peptone-seawater agar

at 28°. Six regularly monitored stations and several supylementary sta

tions were established in the middle and southern seations of Kaneohe Bay.

The latter reaeives aonsiderably treated sewage ~ffluent and some untreated

sewage. In addition" analysis was made of sewage and sewag~ effluent

from the Kaneohe munioipal: sewage plant" the Kaneohe Marine Corps Air

Station (KMCAS) sewage plant" and Coaonut Island. Water from several

small streams along the middle seatoI' of t he Bay was also tested.

The feaal baateria aount was below the maximum set for Class AA

water (aaaording to the water quality standards proposed for the State

of Hawaii) at all the regular stations on alloaaasions. The sewage

treatment plants did not di echarqe any signifiaant numbers of living

miaroorganisms into the Bay; aatually" the effluent from the Kaneohe

muniaipal plant was found to be sterile after ahlorination. The total

counb of bacter-ia in the Bay was generally high" but not alarmingly high.

No aorrelation aould be found between the baaterial aount and the exist

ing weather and tide aonditions.

In aontrast to the low aount of feaal baateria .i n most parts

of the Bay" rather high counbe of ool-if'otme, andeepeeial-lq eniieroooooii,

were found at several stations in shallow water in the middle eeoto»,

The souraes of this aontamination were found to be several of the small

streams emptying into the Bay at this point». The streams from Kahaluu

to Molii" as welZ as the shallow water of the Bay along the aorrespond

ing aoastline" were all found to meet the proposed standards of Class

II fresh water" however.

In addition to the study of bacter-ial: pollution of Kaneohe Bay"

some data were aolleated from the sea south of the island of Maui and

surrounding the island of Kauai.

TABLE OF CONTENTS

LIST OF FIGURES v

LIST OF TABLES ....•..•................ ....... ......... ............... .vi

INTRODUCT ION 1

OBJECTIVES 2

MATERIALS AND METHODS 2Samp1; ng .................. •...• ........................ .-•...•...••. 2

labor ator~ Procedures - ' ,' 2

RESUlTS ' ' 4

Regular Monitoring: Stations 1-6 4Coliforms 35° 4Enterococci 6Total Bacterial Count 6

Sewage Treatment Plants, Sewage Outfalls, and Streams 8Shallow Water, and the Channel Off the Shores BetweenKahaluu and Molii 14Other Observati ons ' ~ 14

DISCUSSION AND CONCLUSIONS 17

ACKNOWLEDGEMENTS 19

BIBLIOGRAPHY 20

APPENDIX ' 21

LIST OF FIGURES

Figure1 Kaneohe Bay Showing Regular Stations, Sewage Plants

and Ou tfa11 s ' 3

2 Position of Station 3 Substations. Sediment Samplingfor Total Bacterial Counts 9

3 Position of Station 2 Substations Near the SewageOutfall from the KMCAS Sewage Plant .........•.............. 11

4 Streams Emptying into Kaneohe Bay Between Kahaluuand Mol';; : 13

v

LIST OF FIGURES (cont'd)

5 Kaneohe Bay. Sampling Stations in Shallow Water(S-Stations) and Near Buoys in the Channel of theCentral Sector (B-Stations) 15

LIST OF TABLES

TableStations 1-6. Numbers of Coliform Bacteria (35°) Per 100 mlof Water 5

2 Stations 2-4. Numbers of Coliform Bacteria (35°) Per Gramof Sediment 6

3 Stations 1-6. Numbers of Enterococci Per 100 ml of Water 64 Sta~ions 1-6. Total Counts of Bacteria Per 100 ml of Water ?5 Stations 2-4. Total Counts of Bacteria Per Gram of Sediment 86 Station 3, Substations. Total Counts of Bacteria Per Gram

of Sediment 8? Kaneohe Municipal Sewage Plant. Numbers of Coliform

Bacteria (35° and 45°) Per 100 ml of Sewage Sampled atDifferent Points of the Treatment Process 10

8 KMCAS Sewage Plant. Numbers of Coliform Bacteria (35°and 45°) Per 100 ml of Sewage Samples at Different Pointsof the Treatment Process 10

9 KMCAS Sewage Outfall Area in Kaneohe Bay. Numbers ofColiform Bacteria (35°) and Total Bacterial Counts Per100 m1 of Water 12

10 Streams Between Kahaluu and Molii (R-Stations). Numbersof Coliform Bacteria (35°), Enterococci and Total Bac-terial Counts Per 100 ml of Water .. : 12

11 Shallow Waters of Kaneohe Bay Between Kahaluu and Molii.Numbers of Coliform Bacteria (35°), Enterococci and TotalBacterial Counts Per 100 ml of Water 16

12 pH Values and Transparency (Secchi Disc) of the Water ofthe Six Regular Stations in Kaneohe Bay l?

13 The Sea South of Maui. Numbers of Bacteria Per 100 mlof Surface Water and Water from 30m-Depth 23

14 Kauai. Numbers of Bacteria Per 100 ml of SurfaceWater and Water from 30m-Depth 24

vi

INTRODUCTION

Kaneohe Bay is an estuary of considerable public and scientific

interest because of its rich and interesting marine life, its proximity

to deep oceanic water of high purity, and because it is so exposed to

prevailing wind and currents that its water can have ready exchanges with

the ocean outside. It is an ideal place to study a variety of marine

sciences. The Hawaii Institute of Marine Biology (HIMB) is located on

Coconut Island in the southern sector of the Bay. The waters of Kaneohe

Bay also supply bait, food fish, and clams and, in addition, offer ample

opportunities for recreational activities, water sports, fishing, boat

ing, etc.

However, the increasing growth of the communities surrounding

Kaneohe Bay is a constant meanace to this unique piece of tropical nature.

At the present time the Kaneohe municipal sewage plant alone daily empties

more than 4 million gallons of secondary-treated sewage into the Bay,

while primary-treated sewage is being discharged from the Kaneohe Marine

Corps Air Station (KMCAS), and small volumes of raw sewage is discharged

from Coconut Island, ships and other sources; streams and run-off from

heavy rains bring sedimentary materials, fertilizers, biocides, deter

gents, etc. into the Bay water.

Testimonies given at the recent public hearing in Honolulu on the

proposed water quality standards for the State of Hawaii disclosed that

"Kaneohe Bay is seriously polluted, to the extent of endangering all pre

sent uses except perhaps that of a commercial harbor." (1)

Although there is ample implication of a general and severe pol

lution of Kaneohe Bay, very little is known about the bacterial contami

nation of the Bay water. The most recent data available are quantitative

assessments of coliforms and enterobacteria published in 1966 by the

State Department of Health (2).I

The present report* is a summary of a bacteriological study of the

water and sediments of Kaneohe Bay and of several suspected sources of

bacterial contamination. The project has been completed in accordance

with and fulfillment of a proposal entitled, A Study of the Bacterial

*A progress report was submitted to the State Department of Health onJuly 5, 1967.

2

Pollution of Kaneohe Bay~ Oahu~ submitted on May 15, 1967 to the Depart

ment of Health of the State of Hawaii and designated as contract No.

9519 between the Department of Health and the University of Hawaii. The

senior author of the report is the project's principal investigator and

Associate Professor of Microbiology, University of Hawaii. The junior

author is a doctoral student in microbiology, University of Hawaii.

OBJECTIVES

The purpose of this investigation was to monitor regularly six

selected stations in Kaneohe Bay (Fig. 1) and to use appropriate bacterio

logical methods to analyze collected water and sediment samples for coli

form bacteria, enterobacteria, and total bacterial counts. In addition,

the bacteriology of the sewage processed by the two sewage treatment plants

adjacent to the Bay was planned. Supporting data, such as weather obser

vations, tidal movements, water temperature and turbidity was compiled.

As the investigation proceeded, it was found necessary to extend

the monitoring coverage with several supplementary stations within the

Bay itself. In addition, a monitoring station was established in each

freshwater stream emptying into the middle sector of the Bay.

MATERIALS &METHODS

Sampling

All samples were collected in sterile J-Z bacteriological water

samplers using an aseptic technique. Samples were obtained from two

depths at each station at the surface and at approximately 1 m above the

Bay bottom.

Sediment samples were obtained at Stations 2, 3, and 4 using a

bottom grab. Each sediment sample was stored in a plastic bag. All sam

ples were transported in the cold to the laboratory .

Laboratory Procedures

Water Analysis. The water samples were analyzed using the standard

3

o

*1

'~ . SOUTHERN'" SECTOR

,.\ :

I,,I," ,,

, I"

,..-" '", '

. ,~: t ,

I • ... ,I

:;,"t, KMCAS.'. :,., ~. SEWAGE

=- - ~ "'" t:DI2 PLANT'II ,'I, HI B 'C:D''t': ,'.' ," M

.. , .. ,I ~ :, COCONUT ISLAND !/.' :., *4 OUTfAL

' ......

'"-; "-... , t

--. "1. ,.'-: " 't,

,t,,_ ,••""""" , •'.... 0..

*5 ",-,MIDDLE "'1 "

•" .. SECTOR '.:..

..,,"~",.~

.111\

.~."~,

~~••..

\---- NORTHERN --------+----------t--- 21°30'""" SECTOR

~ .. ", ....... ,,, ;...-, .. ,."..., "", ,l,

"" ... """,. :-:, J"""l-;-'

~ ,,-:." :

* STATION

",.I'~ REEF ,/ KANEOHE,," ij SEWAGE PLANT

FIGURE I: KANEOHE BAY SHOWING REGULAR STATIONS,SEWAGE PLANTS AND OUTFALLS.

4

membrane filtration and plating technique [Standard Methods (3) and Milli

pore Filter Corp. Technical publication no. ADM 40 (4)].

The samples from each depth were treated in duplicate as follows:

Coliforms 35°. SO ml of each sample was filtered through a 0.4s~ milli

pore filter (type HA) and placed on endo agar for incubation at 35°C for

24 hours. Coliforms produced typical green sheen colonies on this medium.

Coliforms 45°. Same procedure was followed for 45°C incubation. After

early attempts resulted in no growth, this step was eliminated.

Entepococci. SO ml of the sample were filtered through a membrane filter

which was placed on M - enterococcus agar and incubated for 48 hours at

35°C.

Total Count. The sample was diluted to 1:100 using sterile water and 20

ml of the dilution was filtered. This filter was placed on ZoBell agar

(peptone~ferric phosphate-seawater medium) and incubated at room temper

ature for 24 hours before bacterial colonies were counted.

pH. The pH of the sample was determined with a pH meter.

Sediment Analysis. The sediment samples were diluted with sterile water.

Initially, the membrane filtration technique was used for enumeration

of the indicator bacteria. However, since this procedure excluded the

detection of low numbers of coliforms in the sediment, the Most Probable

Number method (MPN) was adapted and used in subsequent tests. All re

corded data are based on the former method since the MPN data were

inconclusive.

RESULTS

Regular Monitoring: Stations 1-6

Coliforms 35°

Watep (Table l). The numbers of 35° coliforms per 100 ml of water

were in all cases found to be extremely low and, with one exception,

well below the upper limit for Class AA water. It was noteworthy that

5

the water at Station 3, sit uat ed so c l ose to the outfall from the

Kaneohe Sewage Treatment Plant , did not show any significantly higher

degree of coliform pollution than water from the background stations.

A possible explanation of the one single high count at Station 1 on

July 1 will be discussed later .

TABLE 1. STATIONS 1 - 6. NUMBERS OF COLIFORMBACTERIA (35 0 ) PER 100 m1 OF WATER .

STATI ON 2 3 4 5 6

JUNE 14 SURFACE 0 0 1BOTTOM 1 16 0

21 SURFACE 22 3 2BOTTO'-1 44 0 0

27 SURFACE 0 0BOTTO'-1 0 0

JULY 1 SURFACE 16 24 2 0BOTTO'-1 400 4 LOST 0

3 SURFACE 0 0 0BOTTO'-1 0 0 0


10 SURFACE 2 2 0BOTTOM 0 6 0


AUG 4 SURFACE 0 20 0BOTTO'-1 0 0 2

7 SURFACE 0 0 2BOTTOM 4 0 0

8 SURFACE 10BOTTO'-1 0

11 SURFACE 0 28BOTTO'-1 0 14

14 SURFACE 0 2 0BOTTO'-1 0 14 0



Sediments (Table 2). Only Stations 2, 3, and 4 were ~uitable for

sediment sampling . The results were somewhat inconsistent, but high

counts were found at Stations 3 and 4.

6

TABLE 2. STATIONS 2 - 4. NUM3ERS OFCOLIFORM BACTERIA (35°) PERGR.AM OF SEDIMENT

STATION 2 3 4

JULY 3 200 4,000,000 0

7 500 0 0

10 0 0 108,000

Enterococci

Water (Table 3). Because of initial difficulties with the diag

nostic medium for enterococci, only four samples obtained in August were

tested. The numbers were, as with the coliforms, generally low, but

possibly higher at Stations 3 and 4 than at the other stations. However,

the data for this group of bacteria is too scarce for any definite con

clusions to be drawn. No data is available for enterococci in sediments.

TABLE 3. STATIONS 1 - 6. NLMBERS OF ENTEROCOCCIPER 100 ml OF WATER .

4 02 2

o 0o 0

STATION 2 3

AUGUST 11 SLRFACE 0 60BOTTOM 0 10

14 SURFACE 2 4BOTTOM 0 18

18 SURFACE 0BOTTOM 0

29 SURFACE 0BOTTO'-1 0

4

128

5 6

Total bacterial count

Water (Table 4). The total count of bacteria reflect, among other

things, the nutrient level of the water, particulate as well as dissolved.

Considering that bacteria tend to become adsorbed to particles present

in the water, it is not surprising that the population assessment shows

a good deal of variation. Generally, the counts found in Kaneohe Bay

are not surprisingly high, although the number of bacteria in pure oceanic

water in the photic zone seldom exceeds 10,000 per 100 mI. The bacterial

population in nearshore waters ranges between 100,000 to several millions

per 100 mI, depending on the nut r ients present in t he water.

7

TABLE 4. STATIONS 1 - 6 . TOTAL COUNTS OF BACTERIA PER 100 m1 OF WATER

STATION 2 3 4 5 6

JUNE 14 SURFACE 400,000BOTTO'1 265, 000

21 SURFACE 15,000,000 5, 000 5,000BOTTO'1 535,000 <5 ,000 <5 ,000

27 SURFACE 28,500 4,500BOTTO'1 13, 500 4,000

JULY SURFACE 10,000 33, 500 6,500 6,000BOTTOM 150,000 6, 500 LOST 1,500

3 SURFACE 360, 000 256, 000 100,000BOTTOM 350, 000 11,000 6, 500

7 SURFACE 35, 000 94,000 10,500BOTTO'1 50,000 160, 000 5,500

10 SURFACE 2, 000 2,000 8,000BOTTO'1 6,000 6,500 34,500

28 SURFACE 55,000 27, 000 136,000BOTTO'1 30,000 1,500 10,500

AUG 4 SURFACE 200 1,800 600BOTTO'1 200 1, 400 < 200

7 SURFACE 1,000 11,600 3,000BOTTO'1 200 9, 200 1,800

8 SURFACE 3,600BOTTO'1 1,600

11 SURFACE 1,200 800BOTTO'1 600 1, 200

14 SURFACE 4,000 18,500 8,500BOTTO'1 1,000 43,500 3,000

18 SURFACE 4,000 2, 200 1,200BOTTO'1 5,600 5,400 1,800

29 SURFACE 2,600 4,600 4, 200BOTTO'1 10,000 6,200 5,400

Sediment (Table 5) . Only Stations 2, 3, and 4 have been monitored .

On three different occasions when samplings were made, high counts ofbacteria were found.

In addition to the r egul ar monitoring, a special sampling was made

on July 17 t o determine the total count in the sediments at Station 3.

Ten substations encirc led the sewage outfall f rom t he Kaneohe municipal

sewage plant (see Fig . 2). The dark brown sediments obtained were free

from sulfide odors and relatively homogeneous with high and fairly con

sistent bacterial counts (Table 6).

8

TABLE 5. STATIONS 2 - 1+. TOTAL C~TS OF BACTE-RIA iER GRAM OF SEDIMENT .

STATION 2 3 1+

JULY 3 22,000 180,000 360,000

7 320,000 1,380,000 880,000

10 11+0,000 1+06,000 3,190,000

TABLE 6. STATION 3, SUBSTATI ONS. TOTAL CQUIlTS OFBACTERIA PER GRAM OF SEDIMENT ( SEE FIG. 2).SAMPLING JULY 17, 1967.

SUBSTATIONS3-1 3-2 3-3 3-4 3-5 3-6

178,000 160,000 162, 000 112,000 204,000 112,000

SUBSTATIONS3-7 3-8 3-9 3-10 3-11 3-12

100,000 228,000 560,000 368,000 1+32 ,000 736,000

Sewage Treatment Plants, Sewage Outfalls, and Streams

As the level of coliform bacteria and enterococci in Kaneohe Bay

was found to be far below that expected for a polluted estuarine, an

investigation was made of the discharge of fecal bacteria into the Bay

from known and suspected sources. For this purpose, bacterial analyses

were made at selected steps in the sewage treatment process at the Kaneohe

sewage treatment plant and the Kaneohe Marine Corps Air Station (KMCAS)

sewage plant. Similar analyses were made near the outfall from the KMCAS

plant and Coconut Island. In addition, several water samples were taken

near the mouths of streams flowing into the Bay between Kahaluu and Molii.

The results of these investigations are reported below.

Kaneohe Municipal Sewage Plant (Table 7). The number of 350 coliforms

was found to decrease with the degree of sewage treatment, and the bac

teria were quantitatively removed during the final chlorination of the

3-4.

3-5 •

3-6 •

3-3• • * STATION :33-2 .3-1

.3-12

3-7 • I •3-8· 3-~ I 3-10

II

t~'ft,~GE

II

~~=:::::~7"/

/,....-<.---~........-- -- - -

[Q] KANEOHESEWAGEPLANT

PIER

FIGURE 2: POSITION OF STATION 3 SUBSTATIONS.SEDIMENT SAMPLING FOR TOTAL BACTERIALCOUNTS JULY 17, 1967.

The same trend was ev ident with 45° coliforms; in fact, the

10

sewage.

sewage effluent was found to be compl etely sterile. This result was

confirmed in a second s ampling made one week later than the first s am

pling . (The personnel of the sewage t reatment plant had not been noti

fied before the second s ampling.)

TABLE 7. KANEOHE MUNI CIPAL SEWAGE PLANT. NUM3ERSOF COLIFORM BACTER IA (3 5° AND 45°) PER100 rnl OF SEWAGE SAMPLED AT DIFFERENTPO INTS OF THE TREATMENT PROCESS. JULY20, 1967.

SAMPLE COLIFORMS 35° COLI FORMS 45°

RAW SEWAGE 25,600,000 0

AFTER PR IMARY SETTLING 9,200, 000 400,000

AFTER BIO FILTER 7,800,000 180,000

FINAL EFFLUENT AFTER

CHLORINE TREATMENT 0 0

KMCAS (Table 8 &Figure 3) . The numbers of 35° coliforms also decreased

for each step of treatment of the sewage at this plant. However, the

final chlorination here seemed to be less heavily applied than at the

muni c i pa l plant leaving about 0.75 million coliforms per 100 ml in the

effluent.

TABLE 8. KMCAS SEWAGE PLANT. NlM3ERS OF COLIFORMBACTERIA (3 50 AND 450 ) PER 100 ml OFSEWAGE SAMPLES AT DIFFERENT POINTS OFTHE TREATMENT PROCESS. JULY 20, 1967.

SAMPLE

RAW SEWAGE

AFTER SETTLI NG

FINAL EFFLUENT AFTER

CHLORINE TREATMENT

COLIFORMS 35°

13, 800,000

8,000,000

760,000

COLIFORMS 45°

o

°o

For this reason, it was found desirable to investigate the outfall

area in the Bay from this plant more closely. Additional stations were set

up near Station 2 and water taken from near the bottom and also from the

surface. In spite of rather turbid water and visible evidence of proxi

mity of the pipe opening, the numbers of coliforms were not found to be

significantly higher in this restricted area than in the Bay in general

11

•2-10

* STATION 2

•2-4 •2-3 •. 2-2

[QJ KMCASI SEWAGEI PLANTII

II

II

II

I

•2-1

-501

-

••----100'---

•_---- 2001

- - - - - -.

FIGURE 3: POSITION OF STATION 2 SUBSTATIONS NEAR THESEWAGE OUTFALL FROM THE KMCAS SEWAGEPLANT. SAMPLINGS JULY 26, 1967.

12

(Tab le 9). However , cons i dering the re lative l y small volume of sewage

discharged from the KMCAS plant (ca. 0. 4 million gallons per day), this

resul t might possibly be explained as an eff ect of di lution .

TABLE 9. KMCAS SEWAGE OUTFALL AREA IN KANEOHE BAY .NUMBERS OF COLIFORM BACTERIA ( 35°) ANDTOTAL BACTERIAL COUNTS PER 100 ml OF WATER.SAMPLING JULY 26, 1967. ( SEE FIG. 3).

SUBSTATIONS COLIFORMS TOTAL COUNTS

2-la SURFACE

jBOTTO'1 0 118, 000

2- 1 SURFACEBOTTO'1 22 200

2- 2 SURFACE 38 2,000BOTTO'1 16 4,000

2- 3 SURFACE 0 360,000BOTTO'1 6 4,000

2- 4 SURFACE 2 2,000BOTTOM 2 2,000

Coconut Island. No coliform bacteria were f ound i n the Bay water near

the sewage pipe from HIMB on Coconut Island.

Streams , R-Stations (Tabl e 10 and Figure 4) . Surface water samples were

taken a few hundred fee t upstream from where the bridges of Highway 83

cross the streams. Only t wo s amples were t aken on the bay side of the

bridge. Both 35 0 col iform and enterococci, as well as, total bacterial

count were determined in each sample.

TABLE 10. STREAMS BETWEEN KAHALUU AND MOll I (R- STATIONS) . NUMBERSOF COLI FORM BACTERI A (35°), ENTEROCOCCI AND TOTAL BACTERIALCOUNTS PER 100 ml OF WATER . SAMPLING AUGUST 16, 1967.

STATION STREAM COLIFORMS ENTEROCOCCI TOTAL COUNT pH

R-la KAHALW (BAYSIDE) 100 6,000 5,200 7.3

R-lb KAHALW (UPSTREAM) 100 4,600 2,800 6.9

R-2 KAALAEA 600 2,000 656 7.3

R-3 WAIAHOLE 600 1,040 400 7.2

R-4 WAIAHOLE (BRANCH) 600 110 74 6.4

R-5a WAIKANE (BAYS IDE) 560 1,200 122 6.9

R-Sb WAIKANE (UPSTREAM) 560 1,100 88 7.2

R- 6 HAK IPW 700 1,040 2,000 7.0

13

WAIKANE

WAIHOLE

HIG~

MOLlI'POND

1 . 1 1 1 1 1 1 1 1 1 11

UJ..U.U) KANEOHE ........1/

WA.UJ BAY ... ""'1111111

COCONUT(}ISLAND

FIGURE 4: STREAMS EMPTYING INTO KANEOHE BAYBETWEEN KAHALUU AND MOLII .R-STATIONS. SAMPLING AUGUST 15, 1967.

14

The results indicate that all of the streams investigated were

heavily polluted with fecal bacteria, but that the total counts were

generally low. Enterococci were predominant, but coliforms were also

present in large numbers, well above the proposed standards for Class I

fresh water.

Shallow Water, and the Channel Off the Shores

Between Kahaluu and Molii

The high count of coliforms and enterococci in the streams between

Kahaluu and Molii suggested that samplings be made in the Bay water along

this coastline. A series of 9 stations (S-stations) were therefore set

up in the shallow waters close to the stream mouths, and 7 additional

stations were set up near buoys in the channel between the Middle Sector

and the Northern Sector (B-stations in Fig. 5).

Surface and bottom water samples from near the buoys (B-13 to B-25)

were taken for analysis but the highest event of 35° coliform was only

10 bacteria per 100 ml, and 9 out of the 14 samples were negative.

In contrast to this almost negative result in the Channel, the sta

tions S-l through 5, which were closer to the shores, showed large numbers

of coliforms and enterococci (Table 11) . The stations marked S-6 to S-9,

adjacent to reefs, were significantly lower in bacterial numbers.

Other Observations

Meteorological observations and correlation between weather and bacterial

counts. By courtesy of KMCAS, weekly data compilations from daily obser

vations of air temperature, wind direction and velocity, cloudiness, etc.

made by the Aerology Branch of KMCAS were made available during the inves

tigation period. A careful study of the data was made with special atten

tion to periods of heavy precipitation (which were frequent in June and

July) and changes in wind direction from the usual trade to Kona conditions

and their effects on bacterial counts.

Tide movements. Tide movements in Kaneohe Bay were recorded during the

sampling period, but again no significant correlation was found between

the observed bacterial numbers and the tidal fluctuations.

15

nCOCONUTUISLAND

,," " -.

,

\ .8-21

~(tS-9 .8-23 (/0.... .8-25

",. ,., '........-, ' I I. .

• I,

,,\"'11 11 /". '" l:::!i",-I" "_. .8-13

~" .' .-

~ 5-4 (t S-8 :-:...., :"~ .8-15 r;. .. ",

"(tS-5 ~ .8-17 ' , ....

:.~ (tS-7 """ _""'.,~S-6 .8-19 -.,_ :, •.-

'1 , 1 1"" "... .-~.

(t S- STATIONS

• 8- STATIONS

--,O

",,-"-'....

"; ., ,,, " ~\,

, I" II I . ', \'

I".,·,,~, REEF",

FIGURE 5: KANEOHE BAY. SAMPLING STATIONS IN SHALLOWWATER (S-STATIONS) AND NEAR BUOYS IN THECHANNEL OF THE CENTRAL SECTOR (B-STATIONS).SAMPLINGS AUGUST 1967.

16

TABLE 11. SHALLOWWATERS OF KANEOHE BAY BETWEEN KAHALUUAND ~LII. NUMBERS OF COLI FORM BACTERIA (35°),ENTEROCOCCI AND TOTAL BACTERIAL COUNTS PER 100ml OF WATER . SAMPLING AUGUST l a, 1967.

STATION COLIFORMS ENTEROCOCCI TOTAL COLNTS

S- l SURFACE 182 792 187,600BOTTOM 88 376 123,600

S- 2 SURFACE 128 368 110,800BOTTOM 252 149,600

S-3 SURFACE 300 1,360 140, 800

S-4 SURFACE 232 504 968

S-5 SURFACE 224 192 33,200

S-6 SURFACE 6 6 1,800BOTTOM 4 0 1,600

S-7 SURFACE 14 6 3,200BOTTOM 8 2 1,600

S-8 SURFACE 4 2 6,500BOTTOM 6 2 2,000

S-9 SURFACE 2 2 4,500

Watep te~e~atupe . The water temperature was recorded prior to each

sampling during the entire period and was found to be fairly constant

during the entire observation period, ranging from 26°C to 2SoC. There

is no reason to believe that these small fluctuations of the water temp

erature should have influenced bacterial counts .

The temperature in the monitored streams was found to range between

23°C and 26°C. .

Watep tpanspapency. Transparency ranges (in meters) for several stations

and the corresponding extinction coe fficients (as computed according to

the formula K = 1.7/D, where D is the transparency measured with the

Secchi disc) are shown in Table 12. If the value for Station 6 is used

as a value for "natural conditions" of s ea water, the deviations of every II

one of the five other stations exceed the 20% limit set for Class B waters. i

pH of the Bay watep. The pH values measured in surface and bottom water

on different occasions (minimum of 4 individual measurements) are given

in Table 12. Stations 1 and 3 (sur f ace only) and Stations 4 to 6 qualify

for Class AA water.

17

TABLE 12. pH VALUES AND TRANSPARENCY eSECCHI DISC) OF 'THE WATER OF THESIX REGULAR STATI ONS IN KANEOHE BAY.

pH TRANSPARENCY eM) EXTINCTIONSTATIoN RANGE ' AVERAGE RANGE AVERAGE COEFFICIENT

SURFACE 8.0-8.2 8.1 6.0-13 .5 11.5 0.15BOTTQ'1 7.1-8.1 7.6

2 SURFACE J . 5- 8 . 1 ,7. 9 3.0-7.0 4.7 0.36BOTTQ'1 7:0-8 .1 7.6

3 SURFACE 7.8 -8.1 8.0 2.0-3.5 2.5 0.43BOTTQ'1 7.4-8 .2 7.9

4 SURFACE 8.1-8.1 8.1 4.5-5.5 5.2 0.33BOTTQ'1 8.1-8 .1 8.1

5 SURFACE 8 ~1-8 . 2 ' 8.2 ' 8.0-10 .5 8.8 0.19BOTTQ'1 8.0-8 ,1 8.1

6 SURFACE 8.1-8.2 8.2 12.5-18.0 15.3 0.11BOTTQ'1 8.0-8 .2 8.1

The pH measurements have two points of interest. One is the gen

erally high (and satisfactory) ' va l ues for Station 3 which in all other

respects was considered 't o be the most polluted station. , Of six separate

measurements only one was lower than pH 8.0 i n the surface water, and

' t hr ee i n bottom water . This clearly shows that pH values are not neces

sari iyan indicat ion of pOlluted 'water and should be interpreted with

caution.

The second point of ' interest was the low pH values found in the

bottom water at -St a t i on 1. An explanation for this is suggested under

DISCUSSION AND CONCLUSIONS.

Maui and Kauai. Data on bacterial counts·, water temperature, and pH in

areas of suspected pollution around Maui and Kauai are reported in the

Appendix to ,this report . ,

DISCUSSION AND CONCLUSIONS

It is evident from the results of this investigation that Kaneohe

18

Bay, with the exception of the nearshore middle sector, is not heavily

polluted with bacteria of fecal origin. Although this is not the expected

result, it is more readily understandable on the basis of the finding, "

that the effluent from the major contributor of sewage material, the '

Kaneohe municipal sewage treatment plant, was virtually sterile. The

small numbers of fecal bacteria originating from the KMCAS plant, Coconut

Island, and other sources apparently are rapidly diluted out or die off

when exposed to sea water.

From a sanitary point of view, the zone of primary concern in

Kaneohe Bay is the nearshore shallow water , in t.hejrtiddLe sector and the

many small streams emptyi~g into the Bay between Kahaluu and Molii. These 1waters are heavily polluted with bacteria of fecai origin, especially

enterococci. This situation was discovered in the very last stage of the

investigation. Lack of time precluded af6110w up. According to the

proposed water quality standards ' for the state of ' Hawaii both the streams.......... . ...

and shallow waters need to only meet the requirements of Class II water

(fresh-water statement). However, it is urgent that the sources of

pol Iu't i.on.ta l.ong the-st.reams be .f cund and, if possible , eliminated. It

, is recommended that other streams not yet investigated be monitored.

High total counts 9f bacteria ,we~e found throughout the Bay, but

this shouldflotbe ,of ,great concern as ,t hey ,pr obabl y contribute, consi

derably to t.he minerali~at~onofth~ large amounts of dissolved an~ parti

;cul at,e organic matter .disch~rged into ,t he, Bay, and thereby do more good

than harm. Of course, the activities of these bacteria might result in

the lowering of the dissolved ,qxygen ,cpntent of the water which can only

', ,: be r-epIeni.shed by photosynthetic actiyity of phytoplankton and by diffu

sion of oxygen from the air.

Relatively high total counts and low pH values were sometimes

found at StatLonT. This station was selected as a background station

' because ' i't: was 5upposed'to be in'a regionof 'pureoceanic water. How

ever, these findings suggest the possibility that some of, the inner Bay

water escapes through the narrow channel near Station 1, presumably from

the area of Station 2, instead'of following 't he main current towards NW

through the middle and northern sectors. Oceanographic data available

;" when these observations were made ~i~ not support the supposition of a

counter-current at Station 1. However, current measurements made by

19

Mr. K. H. Bathen, Department of Oceanography, in Kaneohe Bay late this

summer have shown the presence of an outflowing current near Station 1

and thus support the observations presented here.

ACKNOWLEDGEMENTS

The skillful technical assistance of Miss Diane Hayduk is grate

fully acknowledged.

The cooperation provided by State Department of Health, the City

and County of Honolulu, U. S. Navy, the Hawaii Institute of Marine

Biology, University of Hawaii, and the coordination provided by L.

Stephen Lau and N. C. Burbank, Jr. are also gratefully acknowl~dged.

20

BIBLIOGRAPHY

1. Department of Health, State of Hawaii: Proposed Water Quality stand

ards. Honolulu, April 24, 1967, p. 2 .

. 2. Data on Water Quality of Kaneohe~ Waimanalo and Kailua Bays. Honolulu,

1966.

3. Standard Methods for the Examination of Water~ Sewage~ and Industrial

Wastes. American Public Health Association, Inc . , New York,

1965.

4. Teohniques for Miorobiologioal Analysis. Millipore Filter Corp .,

Technical Paper #ADM40, 1965 .

APPENDIX

II

jI

Maui . (Sept. 1 3~ 1967) . Samplings

the surface a t 10 stat i ons along a

Mol okini and ' Kamaiki Point, .Lanai .

23

APPENDIX

In addition to the .bacteri al monitoFings i n Kaneohe Bay, additional

tests for bac terial pollution wer e made i n other areas of the islands

which were visited quring two cruises on the R/V Teritu, the University

of Hawaii's research vessel.

wer e made at 30~meter depths and at

tri angl e between Lanaina, Maui, :and

Tests f or 35° coliforms and entero-

cocci and t otal bacterial counts wer e made a ccor ding to standard methods

descr ibed in the Kaneohe Bay report. All wor k was done ab()ard the ship

immediately following the sampl ing. The r esults are shown in Table 13.

TABLE 13. THE SEA SOUTH OF Mb.UI . NLX-1BERS OF BACTER IA PER 100 mlOF SURFACE .WATER AND WATER FROM 30m- DEPTH. SEPTEMBER 13, ' 1967. .

WATER TEMP-STATIoN ERATURE DC pH COLI FORMS ENTEROCOCCI TOTAL COLtolT

LAHAINA HARBOR SURFACE 27.8 7.1 2 0 1,80030m 8.1 2 0 1,800

2 HEKILI PT . (Mb.UI) SURFACE 28.2 8.2 10 8 2,0000.5 MILES OFFSHORE 30m 8.3 0 0 10,800

3 OPEN SEA SURFACE 28.2 8.2 4 0 2,40030m 8.2 0 0 5,200


5 /o'OLOK INI SURFACE 28.5 8.2 0 0 4,80030m 8.2 0 0 2,600



8 KAMAIKI PT. (LANAI) SURFACE 28.5 8.1 0 0 26,8000.5 MILES OFFSHORE 30m 8.2 0 0 1,800

9 KIKOA PT. (LANAI) SURFACE 28.0 8:2 2 0 12,8001 MILE OFFSHORE 30m 8.2 0 0 400


'jji

Although a few fecal bacteria were found in the near-shore surface 1,j

wat er s of Stations 1, 2 , 3 , and 9, t he figures, i ncl udi ng total count, .~

.!

and pH do indicate significant bacterial pollution in this ~

not any area. i~

.J@.~ t

"~~':::j

~,

!,~

24

Kauai. (Nov. 18, 1967). The same procedure was followed as in the Maui

samplings and tests. The results are summarized in Table 14. There were

5 stations near major land run-off areas including Nawiliwili Harbor.

Fecal bacteria and relatively high total counts were only found in Nawili

wili Harbor, but their numbers were far too low to be of any significance.

wafer t:rh' v · coliform bacteria (35°) and total bacterial counts per 100 m1 of water 12...

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