Pollution of
crops and
pastures by a
smelter
S m e l t e r 'fall-out' l a n d i n g
potentially toxic metals
h o w m u c h lead, zinc, and
b e l c h e d out o f the smelter's
c a d m i u m these contained.
o n the l e a v e s a n d s t e m s o f
chimney. What goes up must
A s a c h e c k , they also
w h e a t plants d i d n o t
c o m e d o w n , and the metals
m e a s u r e d the c o n c e n t r a t i o n s
apparently c o n t r i b u t e to
e v e n t u a l l y fell to earth,
o f m e t a l s that are very m i n o r
c o n t a m i n a t i o n , e v e n in c r o p s
w h e r e t h e y persist.
c o m p o n e n t s o f the s m e l t e r
g r o w n nearby. W a s h i n g
s m o k e , s u c h as c o p p e r .
w h e a t plants m a d e n o
A t least 3 4 0 0 sq k m o f
l a n d are c o n t a m i n a t e d b y
T h e y found a good
l e a d , a n d i n 2 7 0 sq k m t h e
c o r r e l a t i o n b e t w e e n the
d i f f e r e n c e to t h e i r m e t a l
c o n t e n t ; this w a s n o t
s o i l c o n t a i n s 10 o r m o r e
degree o f contamination o f
s u r p r i s i n g , as t h e
times the general
m o s t p l a n t s a n d the
concentrations o f heavy
' b a c k g r o u n d ' l e v e l o f 10
c o n t a m i n a t i o n o f the soils
m e t a l s i n t h e f u m e s f r o m the
parts p e r m i l l i o n ( p . p . m . ) .
they g r e w in. T h e m o r e
s m e l t e r s h a v e b e e n kept very
C a d m i u m and zinc pollute
c a d m i u m that p o l l u t e s the
l o w for years.
s i m i l a r areas. W e k n o w the
g r o u n d , for e x a m p l e , the
c o n c e n t r a t i o n s o f the
m o r e there w i l l be in a wheat
c o u l d in theory contaminate
c o n t a m i n a n t s i n s o i l and
stalk o r a p a d d y m e l o n leaf.
p l a n t s , b u t w h e a t g r a i n is
T h e farther t h e s c i e n t i s t s
w e l l p r o t e c t e d w i t h i n the
v e g e t a b l e s ( s e e Ecos 7 ) . T o
w h a t e x t e n t are c e r e a l s a n d
W i n d - b l o w n soil dust
travelled a l o n g t h e i r s o u t h ­
h e a d as it d e v e l o p s , a n d the
p a s t u r e s affected, a n d is t h e
b o u n d transect, t h e less
scientists found n o e v i d e n c e
health o f h u m a n s and
contamination they found,
that d u s t h a d c o n t r i b u t e d to
l i v e s t o c k at risk? A t e a m o f
u n t i l , a b o u t 3 5 k m f r o m the
the higher levels o f heavy
researchers from the CSIRO
smelter, the pollutant
metals found in grain g r o w n
concentrations had dropped
near t h e s m e l t e r s .
W i t h increasing distance
f r o m the smelter, p o l l u t i o n
falls t o a ' b a c k g r o u n d ' level.
Z i n c is s h o w n h e r e ; lead and
c a d m i u m c u r v e s are similar.
C o p p e r is a negligible
c o m p o n e n t o f smelter
smoke.
to ' b a c k g r o u n d ' levels
A l l this m a y c o m e as a
similar to those f o u n d
relief to l o c a l farmers, but
e l s e w h e r e i n the State.
w h a t o f the p a s t u r e s that
T h e levels o f heavy metals
f o r m an e s s e n t i a l part o f c r o p
in wheat c a m e well within
rotations? A r o u n d Port Pirie
the l i m i t s set b y State h e a l t h
the m a i n p a s t u r e s p e c i e s are
authorities. W h a t ' s m o r e , the
annual m e d i c and various
pollutant metals b e c o m e
a n n u a l g r a s s e s , w i t h native
diluted during bulk handling
chenopods (species o f goose-
T h e South Australian town
and m i l l i n g , w h e n
foot) and introduced w e e d s .
o f P o r t P i r i e is d o m i n a t e d b y
c o n t a m i n a t e d g r a i n is
I n p l a c e s s t o c k graze o v e r
a metal-refining c o m p l e x ,
blended with wheat from
f o r m e r w h e a t l a n d s that h a v e
incorporating the w o r l d ' s
u n p o l l u t e d areas. T h e
reverted t o s a l t b u s h a n d
largest l e a d s m e l t e r .
r e s e a r c h e r s b e l i e v e that
bluebush, or o n samphire
h u m a n h e a l t h is u n l i k e l y t o
g r o w i n g o n salty s o i l s .
T h e study area.
T h e c o m p l e x almost holds
a n o t h e r r e c o r d : its 2 0 5 - m -
b e e n d a n g e r e d by the h e a v y
high chimney, completed
metals in wheat grain
w h o c a r r i e d o u t t h e study o f
h a r v e s t e d n e a r the s m e l t e r s .
pasture c o n t a m i n a t i o n ,
last A u g u s t , is t h e s e c o n d tallest m a n - m a d e structure
D i v i s i o n o f S o i l s has b e e n
in Australia, surpassed o n l y
tackling these questions.
by a stack at M t Isa.
M r Merry and D r T i l l e r ,
f o u n d that different p l a n t
species took up widely
differing quantities o f metal
M r Richard Merry, D r
K e v i n Tiller, M r Paul de
p o l l u t a n t s , a n d i n different
a n d z i n c f r o m o r e m i n e d at
Vries, and D r Brian
w a y s . C a d m i u m a n d z i n c , it
Broken Hill. T h e smoke
Cartwright took samples o f
a p p e a r s , are a b s o r b e d b y t h e
c l i m b i n g the c h i m n e y
w h e a t a n d p a s t u r e plants
r o o t s , b u t m o s t o f t h e l e a d is
c o n t a i n s traces o f t h e s e
f r o m sites at v a r i o u s
deposited o n shoots, from
heavy metals — and o f other
distances from Port Pirie,
d u s t a n d c h i m n e y fall-out.
e l e m e n t s , s u c h as c a d m i u m ,
including points o n a line
T h e s c i e n t i s t s b e l i e v e that
that o c c u r in s m a l l e r
stretching m o r e than 3 0 k m
s o i l d u s t plays little part i n
s o u t h f r o m the s m e l t e r s . T h e
pasture p o l l u t i o n e x c e p t
T h e s m e l t e r s refine l e a d
a m o u n t s in t h e o r e .
N o w a d a y s t h e s e traces are
scientists c o l l e c t e d both
very s m a l l , b u t f r o m 1 8 8 9 ,
grain and w h o l e tops o f
w h e n the first s m e l t e r b e g a n
w h e a t p l a n t s , as w e l l as
operating, until 1925, w h e n
specimens of some 30
e m i s s i o n s w e r e greatly
pasture s p e c i e s a n d s a m p l e s
reduced following a Royal
o f t h e s o i l s in w h i c h all
C o m m i s s i o n report, an
these plants g r e w .
e n o r m o u s quantity —
perhaps 4 0 000 tonnes — o f
T h e y then analysed the
plants and s o i l s to find o u t
H e a v y metal uptake is
illustrated here b y c a d m i u m :
the m o r e there is in the s o i l ,
the m o r e will c o n t a m i n a t e a
plant. M o s t pasture s p e c i e s
take u p less c a d m i u m than
W a r d ' s w e e d but m o r e than
b l u e b u s h . Soil metal values
w e r e o b t a i n e d by extraction
with a standard reagent,
w i t h i n a b o u t 5—10 k m o f the
EDTA.
t h e s c a l e , the least-
smelters.
W a r d ' s w e e d r e c o r d e d the
highest c a d m i u m and zinc
concentrations, and potato
w e e d t o p p e d t h e list for l e a d ,
w i t h W a r d ' s w e e d n o t far
b e h i n d . A t the other e n d o f
27
v e g e t a t i o n , the r e s e a r c h e r s
c l e a r story o f i n c r e a s e d
introduced from the
b e l i e v e that the a n i m a l s at
h e a v y m e t a l intake near the
Mediterranean region,
greatest risk are t h o s e w i t h i n
s m e l t e r s . F a e c e s f r o m the
s a m p l e s at three t i m e s o f
c o n t a i n s relatively l a r g e
a b o u t 5 k m o f the s m e l t e r
sheep nearest Port Pirie
year, a n d i n c l u d e d p l a n t s at
amounts not only o f
complex.
c o n t a i n e d 4 0 t i m e s as m u c h
v a r i o u s stages o f their life
c a d m i u m b u t a l s o o f sulfur,
c y c l e s , a n d this m a y at least
a n o t h e r e l e m e n t that
partly a c c o u n t for t h e
antagonizes copper.
contaminated plants were
the s p e c i e s o f b l u e b u s h . T h e
s c i e n t i s t s c o l l e c t e d their
Ward's weed, w h i c h was
M r Merry and D r T i l l e r
l e a d as f a e c e s f r o m the s h e e p
feel that this q u e s t i o n o f
o n the m o s t distant p r o p e r t y ,
a n i m a l h e a l t h n e e d s further
w h e r e the a n i m a l s w e r e
i n v e s t i g a t i o n . A study b e i n g
e x p o s e d o n l y to ' b a c k g r o u n d '
h a r d t o assess b e c a u s e
c a r r i e d o u t at the I n s t i t u t e o f
levels o f heavy metals. T h e
t h e s e p a s t u r e s ; are they
several m e t a l s are i n v o l v e d ,
M e d i c a l and Veterinary
c o r r e s p o n d i n g ratio for
b e i n g harmed by their
a n d t h e y interact.
S c i e n c e i n A d e l a i d e is
c a d m i u m w a s 3 0 , a n d for
providing valuable
zinc 4.
variations b e t w e e n species.
S h e e p a n d cattle graze o n
Saltbush is g r a z e d o n s o m e
former wheatlands.
T h e risk is particularly
Z i n c , for e x a m p l e ,
aggravates l e a d t o x i c i t y . O n
information. T h e r e , M r T e e -
the other hand, c a l c i u m and
Siaw K o h and D r G e o f f
these additional heavy
p h o s p h o r u s h e l p t o offset the
J u d s o n are t e s t i n g the i d e a
m e t a l s t o f i n d their w a y i n t o
t o x i c effects o f b o t h l e a d a n d
that the c o p p e r d e f i c i e n c y
the s h e e p ' s o r g a n s . M r K o h
zinc. T h e Port Pirie r e g i o n
observed in sheep grazing
and D r Judson have found
has c a l c a r e o u s soils, w h i c h
n e a r the s m e l t e r s c o u l d b e
three t o five t i m e s as m u c h
p e r h a p s offer s t o c k s o m e
caused by the levels o f heavy
l e a d a n d c a d m i u m i n the
measure o f protection.
m e t a l s i n t h e diet.
T h e scientists s e l e c t e d s i x
W e must expect some o f
b l o o d a n d tissues o f the
s h e e p near t h e s m e l t e r s as i n
the ' b a c k g r o u n d ' s h e e p .
c h e m i c a l diet? T h i s is a
properties from 6 to 4 0 k m
t o u g h q u e s t i o n . It s e e m s that
s o u t h o f the s m e l t e r s , a n d
the risk d e p e n d s t o s o m e
o n t o e a c h f a r m m o v e d 14
largest q u a n t i t i e s o f h e a v y
e x t e n t o n w h i c h s p e c i e s they
s h e e p f r o m the State's
metals also had the l o w e s t
eat. B y c h o i c e , t h e s t o c k take
u n p o l l u t e d south-east.
concentrations o f copper in
the m a i n p a s t u r e p l a n t s , but
Assisted by M r W a r w i c k
their livers — o n l y o n e -
w h e n t h e s e are i n s h o r t
H a c k o f the S o u t h
twentieth the 'normal' value.
supply the animals turn to
Australian Department o f
saltbush and b l u e b u s h , and
Agriculture, they t o o k
that the e x p e r i m e n t a l s h e e p
samples o f b l o o d and faeces
near the smelters m i g h t have
every 3 m o n t h s , a n d e v e r y 6
approached or even reached
m o n t h s t h e y k i l l e d three
a state o f c o p p e r d e f i c i e n c y .
finally t h e burrs (fruits) o f
medic.
I n the s e m i - a r i d c l i m a t e o f
Port Pirie, the g r o w i n g
s e a s o n lasts f o r o n l y 5
Bluebush is less
contaminated than most
plants examined, but stock
turn to it only when the
main pasture species are in
short supply.
m o n t h s and drought
c o n d i t i o n s o c c u r frequently.
T h e s h e e p c o n s u m i n g the
T h e scientists c o m m e n t
sheep o n e a c h property and
T h e faecal a n a l y s e s s h o w
r e m o v e d liver, k i d n e y ,
that o n all p r o p e r t i e s the
m u s c l e , and b o n e samples.
s h e e p i n g e s t e d the s a m e
A n i m a l s vary i n their
T h e analyses s h o w h o w
a m o u n t s o f c o p p e r , s o it
s e e m s l i k e l y that t h e
T h i s m e a n s that s h e e p are
physiological responses, too.
m u c h o f the heavy metals
often driven to r u m m a g i n g
S h e e p a n d cattle tolerate
the s h e e p are s w a l l o w i n g
absorption o f copper-from
the g u t i n t o the b l o o d is
for m e d i c b u r r s , i n e v i t a b l y
l e a d i n their diets at
a n d a b s o r b i n g i n t o their
garnished with a significant
concentrations u p to 300
t i s s u e s , a n d e n a b l e the
impaired, probably by high
quantity o f soil, w h i c h
p.p.m. without s h o w i n g any
researchers to k e e p an eye o n
l e v e l s o f o n e o r m o r e o f the
contains higher metal levels
i l l e f f e c t s , a l t h o u g h they d o
the a n i m a l s ' l e v e l s o f c o p p e r
heavy metals.
than d o the plants. T h e
a c c u m u l a t e the m e t a l . ( T h i s
and other essential elements.
animals' intake o f lead, in
c o n c e n t r a t i o n is m a n y t i m e s
T h e faecal s a m p l e s t o l d a
particular, w i l l r i s e , s i n c e
higher than any the
l e a d is a b o u t 10 t i m e s as
scientists f o u n d in plants
c o n c e n t r a t e d i n s o i l as i n
near Port Pirie.) Other n o n -
C l e a r l y a q u e s t i o n that
w i l l n e e d a n s w e r i n g is
w h e t h e r the m e t a l s
\t
accumulating in livestock
raised near P o r t P i r i e m a y ,
ruminants cannot put up
w h e n the m e a t r e a c h e s t h e
w i t h l e a d l e v e l s n e a r l y as
d i n n e r table, p r e s e n t a
the w a y s i n w h i c h h e a v y
h i g h as t h i s : h o r s e s , for
hazard t o h u m a n h e a l t h .
m e t a l s m a y affect a n i m a l s .
e x a m p l e , c a n tolerate o n l y
C e r t a i n l y t o o m u c h o f any
about 80 p.p.m.
pasture.
S c i e n t i s t s d o n o t k n o w all
o n e metal will be toxic.
Contamination o f wheat
T h e scientists f o u n d lead
crops around a l e a d - z i n c
What's m o r e , s o m e pollutant
concentrations o f
smelter. R . H . Merry, K . G .
m e t a l s a n t a g o n i z e essential
2000 p.p.m. or even more in
Tiller, M.P.C. de Vries,
e l e m e n t s : for e x a m p l e , a n
s o i l s i n the t o w n , a n d w h e a t
and B. Cartwright.
a n i m a l that s w a l l o w s s o m e
a n d p a s t u r e s o i l s near P o r t
Environmental Pollution
c a d m i u m will absorb less o f
Pirie often c o n t a i n e d
the c o p p e r i n its f o o d t h a n i f
3 0 0 - 5 0 0 p . p . m . B e c a u s e the
its m e a l h a d b e e n
most contaminated soils
unpolluted.
g r o w the m o s t c o n t a m i n a t e d
28
Ward's weed, an introduced
annual, takes up relatively
large amounts of cadmium
and zinc in polluted areas.
(Series B), 1 9 8 1 , 2 , 3 7 - 4 8 .
T o x i c metals around Port
P i r i e . Ecos N o . 7 , 1 9 7 6 ,
27-31.