Separate and Combined Effects Of

8/10/2019 Separate and Combined Effects Of

1/6

Volume 24 Nu mb er 8, August 1992

~ l . t t n e t o l h t t u m B u l l e m t

\ o l u m c 2 4 N o 8 , p p 4 1 1 - 4 1 ~ 1 9 ~ 2

P r i n t e d i n G r e a t B r i t a i n

( 1 (1 2 ~ , -~ 2 6 X ~ 2 5 0 0 + 0 0 0

1 9 9 2 P e r ~ a m ( m P r e s s L t d

S e p a r a t e a n d C o m b i n e d E f fe c ts o f

S o lar R ad ia t ion T em p erat u re S a lin ity

a n d p H o n t h e S u rv iv al o f F a e c a l

C o l if orm s in S eaw at er

M L A D E N g O L I Q a nd N A D A K R S T U L O V I (2

Insn tute of Oceanography an d Fisheries P O. Bo x 500 58000 Split Croatia

Th e pre sence o f sun l ight was the major fac tor con-

trol l ing the survival of faecal col i for ms (FC ) in seawater.

Th e re sponses of FC survival to in tens i ty of so lar

radiation, temperature and sal inity were inversely

proport ional . The opt imum pH for FC survival was

between pH 6 and pH 7 wi th rap id dec l ine both above

and be low these values . The c omb ined e f fec t of so lar

radiation and tempera ture on the survival of FC was

expressed by mul t ip le l inear regres s ion . The coef -

f ic ients of partial correlation and beta coeff ic ients ([~) ,

which are used in determin ing the re lat ive importance

of so lar rad iat ion and temperature , sugges t that

variations in solar radiation have more effect than vari-

at ions in temperature in br inging about chan ges of Tg0

( t ime required for a 90 reduct ion in bacter ia l number)

for FC. T he increa se o f temperature and sa l in i ty was

more detr imental to FC survival in the presence of

sun l ight sugges t ing that the sun l ight may have ac ted

synergist ical ly w ith temp erature or sal inity.

K n o w l e d g e o f t h e d i e - o ff o r d i s a p p e a r a n c e r a te o f

c o l i f o rm b a c t e r i a , o f t e n e x p re s s e d

as T9

( t im e r e q u i r e d

fo r a 9 0 r e d u c t i o n i n b a c t e r i a l n u m b e r ) , is p a r t i c u la r l y

i m p o r t a n t f o r t h e d e s i g n o f m u n i c i p a l s e w a g e o u tf a l ls

in to the sea (Bel la i r et aL 1 9 7 7 , F i s c h e r & B ro o k s ,

1 9 7 2 ) . C o l i fo rm b a c t e r i a a p p e a r t o e x h i b i t r a p i d d i e -o f f

a f t e r e n te r i n g t h e s e a w a t e r . A r e v i e w o f t h e p u b l i s h e d

re p o r t s (M i t c h e l l & M o r r i s , 1 9 6 9 , F a u s t

et al .

1975 ;

F u j i o k a et al . 1981) revea l s tha t in mos t s tud ies the

c o l i fo rm b a c t e r i a w e re r e p o r t e d t o s u rv i ve fo r d a y s i n

s e a w a t e r . H o w e v e r , i n s o m e in situ s t u d i e s t h e s e

b a c t e r i a h a v e b e e n r e p o r t e d t o b e e f f e c t i v e ly i n a c t i v a t e d

w i t h i n a f e w h o u r s . M o re o v e r , s o l a r r a d i a t io n ,

t e m p e ra t u r e , s a l i n i t y , p H , p r e d a t i o n , c o m p e t i t i o n fo r

nu t r i en t s , ly s i s , and a lga l tox ins have a l l been repor ted

t o b e t h e p r i m a r y m e c h a n i s m b y w h i c h c o l if o r m

b a c t e r i a a r e k i l l e d o r t h e i r n u m b e r s a r e r e d u c e d i n t h e

m a r i n e e n v i ro n m e n t .

Th e m a j o r i t y o f t h is w o rk h a s n o t c o n s i d e re d t h e

i n t e r a c t i o n b e t w e e n e n v i ro n m e n t a l f a c t o r s w h i c h c a n b e

i m p o r t a n t f o r t h e l e v e l o f e x p re s s i o n o f t h e c o l i f o rm

b a c t e r i a s u rvi v al . Th e p u rp o s e o f th i s s t u d y w a s t o

d e t e rm i n e t h e e f f e c t o f s o l a r r a d i a t i o n , t e m p e ra t u r e ,

sa lini ty , an d p H on the su rv iva l o f faeca l co l i fo rm s (FC)

i n s e a w a t e r . Th e s o l a r r a d i a t i o n - t e m p e ra t u r e a n d s o l a r

r a d i a t i o n - s a l in i t y c o m b i n e d e f f e c t s w e re p a r t i c u l a r ly

inves t iga ted . F ina l ly , re la t ive impor tance o f the s tud ied

p a ra m e t e r s i n c o n t ro l l i n g t h e s t a b i l i t y o f F C i n m a r i n e

e n v i ro n m e n t i s d is c u s s e d .

M a t e r ia l a n d M e t h o d s

M o d e ra t e l y t o h i g h l y p o l l u t e d s e a w a t e r ( c o n c e n t r a -

t i o n o f F C v a r i e d f ro m 1 0 3 -1 0 5 1 -1) w a s u s e d i n b o t h

f ie ld and labora to ry exper imen ts . In th i s way , the s t res s

a t i n o c u la t i n g t h e e x p e r i m e n t a l v o l u m e o f s e a w a t e r w i t h

F C p re v i o u s l y g ro w n i n m e d i u m w a s a v o i d e d . I n f i e l d

e x p e r i m e n t s s e a w a t e r w a s r e p l a c e d i n t h e a r e a f ro m

w h e re i t h a d b e e n c o l l e c t e d t o k e e p t h e c o n d i t i o n s a s

n a t u r a l a s p o s s i b l e . D u r i n g t h e e x p e r i m e n t s t h e n u m b e r

o f F C w a s d e t e r m i n e d b y m e m b r a n e f il tr a ti o n m e t h o d

( U N E P / W H O , 1 9 8 3) us in g th e m - F C m e d i u m ( D i fc o ).

Th e e f f e c t o f e n v i ro n m e n t a l f a c t o r s o n s u rv i v a l o f F C

w a s s t u d i e d b y a s e t o f e x p e r i m e n t s (Ta b l e 1 ).

Ex p e r i m e n t s w i t h th e s e p a ra t e e f f e c t s o f t e m p e ra t u r e ,

s a l i n i t y , a n d p H w e re p e r fo rm e d i n t h e d a rk t o e x c l u d e

t h e i n f l u e n c e o f l ig ht . D u e t o l o w d i e -o f f r a t e o f F C i n

t h e d a rk t h e s e e x p e r i m e n t s w e re c a r r i e d o u t o v e r a

l o n g e r p e r i o d o f ti m e (2 4 h r ) .

In exper imen ts wi th sa l in i ty , seawater was d i lu ted

w i t h n a t u r a l u n p o l l u t e d f r e s h w a t e r t o o b t a i n l o w e r

sal in i ties. Sinc e there is no s ignificant d iff eren ce

b e t w e e n t h e e f f e c t s o f e q u a l l e v e ls o f s e a s a l ts a n d N a C I

(Ayres , 1977 ; Car lucc i & Pramer , 1959a) sa l in i t i es

h i g h e r t h a n t h o s e o f s e a w a t e r w e re o b t a i n e d b y a d d i n g

N a C 1 . In e x p e r i m e n t s w i t h p H e i t h e r K O H o r H C 1 w a s

u s e d t o a d j u s t p H t o t h e d e s i r e d r a n g e .

R e s u l t s

Effec t o] Temperature

Th e t e m p e ra t u r e o f s e a w a t e r s t r o n g ly a f f e c t e d t h e

s u rv iv a l o f F C . A d e c re a s i n g e x p o n e n t i a l r e l a t i o n s h ip

411


2/6

T A B L E 1

List of experiments

Marine Pollution Bullet~i

Factor

S e p a r a t e effects

1 Solar radmtlon (Win -2)

2 Solar radiation

3 Temperature (C)

4 Temperature

5 Salinity ( 0)

6 pH

C o m b i n e d e f fe c t:

1 Solar radmtmn- tempera ture

2 Solar radmtmn- tempera ture

3 Solar radiatlon- sahmty

Type of Vessel Duration of Number of

experiment Range Depth Type* Volume experiment recordings

Field 510-8301 Surface TPB 201 3 h 5

Field ( )~ 0-45 m GB 1 51 3 h 2

Field 14 5-24 9 Surface BPB 201 24 h 8

Laboratory 4-3 7 - GB 1 51 24 h 5

Laboratory 6-4 0 - GB 1 5 1 24 h 5

Labora tory pH 4-pH 9 - GB 1 5 1 24 h 5

Field t, Surface TPB 201 3 h 5

Laboratory Light-dark , 12 1-23.8 - GB 1 51 6 (24) h 5 (6)

Laboratory Light-dark, 10-35 - GB 1 5 I 6 (24) h 6 (7)

*TPB--transluce nt polyethylene bag, BPB--black polyethylene bag, GB--glass bottle

~ Vertical distribut ion of solar radiation was expressed as a relative value wah respec t to solar radiation at the surface

A

1 3 0 . . . . . . ' ' ' ' ' F ' ' ' '

',

~ \ \ \ \

e

1 i , i , - ' . . . . 1 . . . . i . . . . 1

1 0 ; li t 3 0 4 0

T E I I P E R R T U R E C )

Fig. 1 Effect of temperatu re on the survival of FC m field and labora t-

ory experiment . (A) Field experimen t (Regression model

y~exp(a+bx); a= 5 93; b=- 008 37, R2~9562 ) (B)

Laboratory experiment (Regression model y=ex p(a+ bx),

a= 6 40 5: b= - 0 082, R2~98 88 ) 99 and 95 confidence

hmgs are plotted.

existed between the survival rate of bacteria (expressed

as T90 )

and water tempera ture (Fig. 1). There was not

sigmficant difference between the two regressions (both

the intercepts and the slopes differences were tested by

t-test, P > 03). In both field and laboratory experiments

the value of T90 decreased by about 55 for each 10C

water temperature increment.

Effect of Solar Radtation

The response of the survival of FC to solar radiation

r ' l 4 \ ,

.

~t

0 J . . . . i . . . . J . . . . t . . . .

1 5 1 .0 8 1 0 7 1 8

8 1 0 9 1 0

S O LR R R ~ Z A T Z O H

Fig. 2 Effect of solar radiation (Win--') on the survival ot FC

(Regression model y=exp(a+bx), a=39 05, b= -0 00 47 ,

R-'= 95 69 ) 99 and 95 confidence hmlts are plotted

was inversely proportional (Fig. 2). During the study,

solar radiation ranged be tween 510 and 830 Wm -2.

The value of T9o decreased by about 40 for each 100

Wm-2 solar radiation increment.

Figure 3 shows the relative decrease of solar radi-

ation with depth resulting in the increase of Tg0 value.

Solar radiation strongly affected the survival of FC in

the first 30 m below the surface. Below 30 m, the effect

of solar radiation was very weak because at that depth

solar radiation accounted for only 10 of the intensity

at the surface.

om bm ed Effect of Temperature and Solar Radiation

The survival of FC under different combinations of

temperature and solar radiation was examined m field

experiments (Table 2). The results of the analysis of the

simultaneous effect of temperture and solar radmtion

on the survival of FC (expressed as T90 are shown m

Table 3. Multiple linear regression was used to

investigate the combined effect of both independent

variables (solar radiation and temperature) on FC

survival. The relationship between T~o and the

simultaneous effect of solar radlanon and temperature

is expressed by the regression shown in Table 3. The

coeffictent of multiple determination, which measures

the overall degree of association between T~0 and

independent variables, was R 2=0.966. That is, 96.6

of the variance in the Tg, can be explamed with solar

412


3/6

V o l u m e 2 4 / N u m b e r 8 A u g u s t 19 9 2

l i e

.~

8 O

n,.n (DO

I,,-

1 4

A

- .

~ e.l,i [~I. ..

' . . . . I , , , i 1 t - i . . . . i . . . . i

l . 1. 0 ; ~O 3 0 4 0 i O

D E P T H m )

8 0

o o

2 0

0

B

/ /

/ /

/ /

/ ~ j /

. . . . t . . . . i . . . . i . . . . i . . . .

O

. . 8 ; ~ e 3 0 4 0 S O

O E P T H ( m )

c

8 0 ' '

' ' ' ' ' '

II

II

4 O

~,

L

0 x

a

I - i E O x .

O = 0 4 0 ~ 0 8 0 I . O 0

R ~ Z A T X O I ' I ( Y , )

F i g . 3 E f f e c t o f s o l a r r a d i a t i o n o n t h e s u r v i v a l o f F C d e p e n d i n g o n

d e p t h ( A ) R e l a ti v e d e c r e a s in g o f s o l a r r a d I a h o n d e p e n d i n g o n

d e p t h ( R e g r e s s i o n m o d e l y = e x p ( a + b x ) , a ~ 4 . 5 1 4 ,

b = - - 0 . 0 8 4 4 , R 2 = 9 9 6 1 % ) ( B ) V e r t ic a l d i s t r i b u t i o n o f t h e T ~o

v a lu e ( R e g re s s io n m o d e l , y = e x p ( a + b x ) , a = 1 2 3 9 ,

b = - 0 0 6 7 7 , R 2 = 9 4 5 0 % ) ( C ) E f fe c t o f r e la t iv e d e c r e a s in g o f

t h e s o l a r r a d l a h o n i n t e n s i t y o n t h e T 9 0 v a l u e ( R e g r e s s i o n m o d e l

y = a x L I n ( a ) = 4 80 7 , b = - - 0 7 8 7 , R z = 9 5 1 2% ) 9 9 % a n d 9 5 %

c o n f i d e n c e l i m i t s a re p l o t t e d

radiation and water temperature. The relatwe import-

ance of solar radiation and temperature is shown by the

coefficient of partial correlation. The correlatton

between T90 and solar radiation when the effect of

temperature was removed was very similar to that when

the effect of temeprature was present. On the other

hand, the coefficient of correlaUon between T 9 0 and

temperature decreased from 0.700 to 0.514 when the

effect of solar radiation was removed. This suggests that

solar radiation is more important than temperature in

T A B L E

2

S u r v iv a l o f F C i n t h e d if f e r en t c o m b m a U o n s o f t e m p e r a t u r e

s o l ar r a d i a U o n ( W m 2 )

( C ) a n d

T e m p e r a t u r e S o l a r I n k T9 0 R 2

( C ) r a d i a t i o n n * ( N 0 ) t ( h - 1) ~ ( h ~ ) (% )

2 0 7 7 3 0 5 7 1 9 1 3 3 1 7 3 9 8 4

1 4 5 6 9 8 5 7 5 2 1 2 1 1 9 0 9 7 3

2 1 . 7 6 5 0 5 7 0 3 1 2 3 1 8 7 9 6 1

1 6 4 5 1 0 5 7 7 3 0 . 49 4 7 0 9 3 8

2 4 9 8 3 0 5 8 1 2 2 4 0 0 9 6 9 8 1

* n - - N u m b e r o f d a t a p o i n t s f o r e a c h t e m p e r a t u r e - s o l a r

c o m b i n a t i o n

? N 0 - - N u m b e r o f F C i n t im e t o

: ~ k - - D l e - o f f r a t e o f f a e c a l c o l i f o r m s

r a d i a t i o n

T A B L E 3

S i m u l t a n e o u s e f f e c t o f s o l a r r a d i a t i o n a n d t e m p e r a t u r e o n t h e s u r v i v a l

o f F C

Va riab le R Rp a b l , b 2 [~-coeff

S o l a r r a d i a ti o n - - 0 9 7 8 - - 0 9 6 8 - - 0 0 0 4 3 2 - - 0 8 9

3 9 8 5

T e m p e r a t u r e - - 0 7 0 0 -- 0 5 1 4 - - 0 0 1 8 7 0 - - 0 1 4

R p - - C o e f f i c l e n t o f p a r ti a l c o r r e l a t i o n

a , b 1 , b 2 - - C o e f f I c I e n t s o f m u l t i p l e l i n e a r r e g r e s s i o n ( f o r n = 5 )

y = e x p ( a + b l x l + b 2 x 2 ) , y - T g 0 0 a -] ), x , - - s o l a r r a di a ti o n ( W in - 2) ,

x 2 - t e m p e r a t u r e ( C) ( c o e ff i ci e n t o f m u l ti p l e d e t e r m i n a ti o n ,

R 2 = 9 6 .6 3 % , P = 0 0 3 1 7)

1 3 - c o e f f i c i e n ts - - R e g r e s s i o n c o e f f i c i e n t s s t a t e d i n t e r m s o f t h e i r

s t a n d a r d d e v i a t i o n s

changing Tg0. Beta coefficients [3) regression coef-

ficients stated in terms of their standard deviations) are

also useful in determining the relative importance of

these two independent variables. That is, each increase

of one SD in the value of solar radiation will be

accompanied if temperature stays constant) by a

decrease of 0.89 SD in the value of T 9 0 . Each increase

of one SD in the value of temperature will be accom-

panied if solar radiation stays constant ) by a decrease

of 0.14 SD in the value of Tg0. It is evident that solar

radiation probably accounts for much more of the

actual change m T90 than does temperature.

Experiments with two different temperatures in light

and dark conditions support the fact that solar radi-

ation is more important than temperature as a factor

responsible for ehmination of FC from the marine

environment Fig. 4). T90 of FC was about 27 times

shorter in the light than in the dark, while the increase

of temperature from 12-24C this range corresponds

to yearly oscillations of seawater temperature in the

Adriatic Sea) was accompanied by the decrease of T~0

of only 2.5 times.

Analysis of variance ANOVA) confirms significant

separate effects of temperature and solar radiation on

the survival of FC Table 4). Significant interact ion

dependence of the effect of one factor on the level of

another) between temperature and solar radiation is

particula rly ~mportant. It indicates that the effects of

temperature and solar radiation are not simply additive

but are synergistic in their effect.

ffect of Sahntty

An inverse relationshtp existed between FC survival

413


4/6


5/6

Volume 24/Number 8 August 1992

T A B L E

5

Results of 2-way ANOVA comparing the effects of sahmty and solar

radiation on the survival of FC

Sourc e of ,~ar]atlon SS df MS

Sahmty (Sa) 8970 8 1 8970 8

Solar radi atio n (S) 17 610 3 1 17 610 3

Intera ction (Sa x S) 2998 8 1 2998 8

Err,~r 812 6 8 10l 6

Tola l 30 392 5 11

F P

883


6/6

C h a m b e r l i n , C E M i t c h e l l , R ( 1 9 7 8 ) A d e c a y m o d e l f o r e n t e r i c

b a c t e r i a in n a t u r a l w a t e r s I n

Wa ter Pollutton Mtcrobtology

( R

M i t c h e l l , e d ) , V o l 2 , p p 3 2 5 - 3 4 8 J o h n W i l e y S o n s , N e w Y o r k

D u t k a , B . J ( 1 9 8 4 ) S e n s i t iv i t y o f

Le glone lla p ne umo phda

t o s u n h g h t

m f r e s h a n d m a r i n e w a t e r s . Appl Envwon Mtcroblol 4 8 . 9 7 0 - 9 7 4

F a u s t , M A , A o t a k y , A E H a r g a d o n , M T ( 1 9 7 5 ) E f f e c t o f

p h y s i c a l p a r a m e t e r s o n t h e i n s lt u s u r v iv a l o f Escherwhta colt M C - 6

m a n e s t u a r l n e e n v i r o n m e n t

Appl Env t ron Mtc robzol 3 0

8 0 0 -

8O6

F i s c h e r , H B B r o o k s , N . H ( 1 9 7 2 ) T e c h n i c a l a s p e c t s o f w a s t e

d i s p o s a l I n th e s e a t h r o u g h o u t l e t s I n

Marme Pollunon and Sea Ltfe

( M R u v i o , e d ), p p 4 6 4 - 4 7 1 F A O , R o m e

F u j l o k a , R S , H a s h i m o t o , H H , S i w a k , E B Y u n g , R H F (1 9 8 1 )

E f f e c t o f s u n l i g h t o n s u r v i v a l o f i n d i c a t o r b a c t e r i a i n s e a w a t e r

A p p l

Environ Mtcrobtol 4 1 , 6 9 0 - 6 9 6

G a m e s o n , A L H , P ik e , E B D a v e y , K . W ( 1 9 7 3 ) M o r t a l it y o f

c o h f o r m b a c t e r i a i n s e a w a t e r s a m p l e s m d a y h g h t . I n Proceedings of

the 5th International Colloqutum on Medwal Oceanography; p p

3 5 3 - 3 6 2 M e s s m a

M a r i n e P o l l u t i o n B u l l e t i n

M c C a m b r l d g e , J M c M e e k i n , T A ( 1 9 8 1 ) E f f e c t o f s o l a r r a d m t l o n

a n d p r e d a c i o u s m l c r o o r g a m s m s o n s u r v iv a l o f f ae c a l a n d o t h e r

b a c t e r i a A p p l E n v i r o n M t c r o b t o l 4 1 , 1 0 8 3 - 1 0 8 7

M c F e t e r s , G A S t u a r t , D G ( 1 9 7 2 ) S u r v i v a l o f c o h f o r m b a c t e r i a i n

n a t u r a l w a t e r s F i e l d a n d l a b o r a t o r y s t u d i e s w i th m e m b r a n e f i lt e r

c h a m b e r s A p p l E n v i r o n M w r o b l o l 2 4 , 8 0 5 - 8 1 1

M i t c h e l l , R M o r r i s , J C ( 1 9 6 9 ) T h e f a te o f i n t e s t i n a l b a c t e r i a m t h e

s e a I n A d v a n c e s m W a t e r P o l l u ti o n R e s e a r c h (S H J en k i n s , ed ), p p

8 1 1 - 8 2 1 P e r g a m o n P r e ss , O x f o r d

S o t i r a c o p o v l o s , S , S p a l a , D . A n d r l o t l s , M P a p a d a k l s , J A ( 1 9 8 2 )

B a c t e r m l d i e - o f f r a t e s i n t h e S e r o n t k o s G u l f V I J E t u d P o l h a lo n s

C a n n e s C I E S M , 6 2 5 - 6 2 9

T u d o r , M , go l Id , M K r s t u l o v l d , N ( 1 9 9 0 ) T , 0 o f t o t a l c o h f o r m s ,

f a e c a l c o h f o r m s a n d f a e c a l s t r e p t o c o c c i i n t h e K a g t e l a B a y A c t a

A d n a t 3 1 , 6 7 - 7 4

U N E P / W H O ( 1 9 8 3 ) D e t e r m i n a t i o n o f f a e ca l c o h f o r m s in s e a - w a t e r

b y t h e m e m b r a n e f i l tr a ti o n c u l tu r e m e t h o d R e f e r e n c e M e t h o d s f o r

M a n n e P o l h m o n S t u d te s N o 3 , R e v 1 , U N E P

E d i t e d b y D. J . H . Ph i l l ip s

T h e o b j e c t iv e o f B A S E L I N E is to p u b l is h s h o r t

c o m m u n i c a t i o n s o n d i f f e r e n t a s p e c t s o f p o l l u t i o n

o f th e m a r i n e e n v i ro n m e n t . O n l y t h o s e p a p e r s

which c lear ly iden t i fy the qua l i ty o f the da ta wi l l

b e c o n s i d e re d fo r p u b l i c a t i o n . C o n t r i b u t o r s t o

B a s e l i n e s h o u l d r e f e r t o ' B a s e l i n e - - T h e N e w

F o r m a t a n d C o n t e n t '

( M a r . P o l l u t. B u l l .

24 , 124) .

Marine PolhatonBulletin

Volum e24 No 8, pp 416 418 1992

Printed m G reat Britain

0025 326X 92 S500+ 000

1992 PergamonPressLtd

D i s t r ib u t i o n o f H e a v y M e t a l s

in P r a w n s f ro m N o r t h e r n

Terr i tory Austra l ia

N . P E E R Z A D A , M . N O J O K a n d C . L E E r

*Sc hoo l o f Ch emis try Ea r th Sc iences , Facul ty o f Sc tence ,

Nor thern Termory Universay , Casuarma,

No r thern Terr ttory 0811, Aus tra l ia

t Schoo l o f Bto log tcal Sc tences , Facul ty o f Sc ience ,

No r thern Terr itory Untvers ity , Casuarma,

Nor th ern Terr ttory 0811, Au s trah a

T h e c o n c e n t r a n o n s o f m e t a l s in m a r i n e o r g a n is m s c a n

m c r e a s e b y m a n y o r d e r s o f m a g n i tu d e a b o v e b a c k -

g ro u n d l e v e l s (F 6 r s t n e r & W i t t m a n n , 1 9 8 3 ; F u rn e s s &

R a i n b o w , 1 9 9 0 ; P e e r z a d a

et al. ,

1 9 9 0 ) , t h u s d e m o n -

s t r a t l n g t h e i r p o t e n t i a l a s s e n t i n e l a c c u m u l a t o r s o f

heavy meta l s (Ph i l l ip s , 1980 ; Sou le & Kleppel , 1988) .

Th e g e n e ra l i s o l a ti o n o f N o r t h e rn Te r r i t o ry f ro m t h e

r e s t o f A u s t r a l i a p ro v i d e s a n i d e a l s i tu a t i o n t o a c q u i r e

b a s e l i n e i n fo rm a t i o n o n h e a v y m e t a l c o n c e n t r a t i o n s i n

a q u a t i c e n v i ro n m e n t s w h i c h a r e f r e e f ro m a n t h ro p o -

g e n i c p o l l u t i o n . Th e s e d a t a a r e u s e fu l f o r c o m p a r i s o n

w i t h t h o s e f ro m o t h e r i n d u s t r i a l i z e d l o c a t i o n s i n

A u s t r a l ia , p a r t i c u l a r ly H a w k e s b u ry R i v e r , S y d n e y a n d

Y a r r a R i v e r , M e l b o u rn e , w h e re h e a v y m e t a l c o n c e n t r a -

t i o n s a r e k n o w n t o b e r e l a t i v e l y h i g h (M a c k a y

et al. ,

1975 ; Ph i l ip et al. , 1 9 7 5 ) . A w e a l t h o f k n o w l e d g e n o w

e x i s t s f o r h e a v y m e t a l s i n m a rm e o rg a n i s m s i n m a n y

a re a s o f t h e w o r l d , w h i l e c o m p a ra t i v e l y l i t t l e i n fo rm a -

t i o n i s a v a i l a b l e fo r A u s t r a l i a n s p e c i e s (D e n t o n &

Breck , 1981) , par t i cu la r ly f rom the t rop ica l reg ion o f

N o r t h e rn Te r r i t o ry . I n t h i s p a p e r w e r e p o r t p r e l i m i n a ry

re s u l t s o f a n o n g o i n g b a s e h n e s t u d y i n t o h e a v y m e t a l s ;

i r o n, c a d m i u m , z i n c , m a n g a n e s e , c o p p e r , s i lv e r a n d l e a d

c o n c e n t r a t i o n s a r e r e p o r t e d i n f i e ld p o p u l a t i o n s o f t w o

s p e c i e s o f p a l a e m o n i d p r a w n s f ro m A d e l a i d e R i v e r ,

N o r t h e rn Te r r i to ry .

Th e s a m p l i n g s i t e , a t A d e l a i d e R i v e r i s a b o u t 8 0 k m

b y ro a d n o r t h e a s t o f D a rw i n . I t h a s n o k n o w n

i n d u s tr i a l o r a n t h ro p o g e n l c i n p u t, a n d i s u s e d fo r

recrea t iona l f i sh ing and p rawning . I t i s sub jec ted to two

s e a s o n s ; a d ry s e a s o n e x t e n d s f ro m A p r i l t o O c t o b e r ,

w h e n s o u t h e a s t t r a d e w i n d s p r e v a i l , a n d a w e t s e a s o n

e x t e n d s f r o m N o v e m b e r t o A p r i l , w h e n t h e n o r t h w e s t

m o n s o o n o c c u r s . D u r i n g t h e l a t t e r p e r i o d , c y c l o n e s c a n

b e e x p e r i e n c e d , p a r t i c u la r l y i n th e m o n t h s o f F e b ru a ry

a n d M a rc h . Th e a n n u a l r a i n f al l m e a s u re d a t D a rw i n

A i rp o r t w a s 1 4 8 1 m m i n 1 9 9 0 a n d m o s t o f ~t ( 9 8 ) fe l l

d u r i n g t h e w e t s e a s o n (A n o n . . 1 99 1 ). Th e w a t e r

q u a h t i e s o f t h e r iv e r s in t h e N o r t h e rn Te r r i t o ry c h a n g e

b e t w e e n s e a s o n s a n d H a r t e t a l . (1 9 8 7 ) fo u n d t h a t

e l e v a t e d l e v e l s o f c o p p e r , z i n c a n d l e a d e n t e r e d t h e

c a t c h m e n t s o f N o r t h e rn Te r r i t o ry d u r i n g t h e w e t s e a s o n

a n d t h e s e d e c re a s e d d u r i n g t h e d ry s e a s o n .

Tw o s p e c i e s o f w i l d p r a w n s , M a c r o b r a c h m m r o s e n -

b e r g i

a n d

M n o v a e h o l l a n d t a e

w e re c o l l e c t e d f ro m

b r a c k is h p a r t o f A d e l a i d e R i v e r m M a r c h 1 9 9 0. T h e

p ra w n s w e re d i v i d e d i n t o s i z e g ro u p s o f v a r i o u s

c a r a p a c e le n g th ( C L i n m m ) : 1 5 - 1 9 : 1 9 - 2 2 f o r t h e

smal le r M . n o v a e h o l l a n d l a e a n d a si ng le 2 2 - 5 2 m m C L

s i z e g ro u p fo r M . r o s e n b e r g l F o r t h e s m a l l e r s p e c i e s ,

t h e h e p a t o p a n c re a s , o v a r i e s a n d g i l l s f r o m 6 -8 p r a w n s

416

Documents

Separate and Combined Effects Of