A b
s
t
r a c
t
St
o rm
e v e nt
s a nd
th
e c o r r e sp
o nd i
ng
r u n of f
of
te n
r e s ult
in
a s ub
sta n
t
ia
l i
n
c r e a s ei
nm i
c r ob i
al
a nd
p
a rt
ic u
l
at
e s ol i d
slo a
d in
g
t
o r e c eiv
i
ng
w
at
e r s.M
ic r o
b i
al
-p
a rti
cle
i
n t
e r a ct
io n s a r e
i
m
p
o rt
an t
d
et
e rm i
n a nt
s of m i
c r ob i
al f
at
e a nd
t
r an
sp
o rt
, a sm i
c r ob
e s a s s o ci
at
ed
w
i
th
p
a rt
i
cl
e st
e nd
to
s et t
l
e o ut
of w
at
e r s,w h i l
em i
c r ob
e si
nt
h
ef
r e ep
h
a s em
ay
t
r a v el
m
u ch
g
r e at
e rd is
t
a n c e sd
ow
n st
r e am
.T h
e s ei
nte r a c
t
i
o ns
al
s oi m
p
a ct t
h
e ef f
e ct
iv e n e s s o
f d
et
e nt
io n
b
a sin
sf
o rm i
c r ob i
al
r e
m
o v al fr o
m
st
o rm w
at
e rT h
ep
a rti
t
io n
i
ng
of
s e v e r al m ic r o
b i
al
sp
e ci
e s(
f
e c al
co
l i f
o rm
s,E
c o
li
, e nt
e r o c o c ci
,C
l
o st
r
i d i
um p
e rfr
i
ng
e n s sp
o r e s, an
d
t
ot
al
c ol i
p
h
ag
e)
w
a si
n v e st
i
g
at
ed i
nu r
b
a n st
o rm w
at
e r r u n of f
G
r ab
s am
p
le s
w
e r eta
k
en
u nd
e rb
a ck
g
r o u nd
c o nd it
io n s a n
d d
u rin
g
s
t
o rm
e v e nt
s, a nd
s am p l
e sw
e r e al
s ot
ak
e nthr o u
g h
o ut
o n e st
o rm
e v e nt
.T
h
efr
a ct
i
o n of
o r
g
a ni
sm
s a s s o cia
t
ed w i
t h
s et t
l
e ab l
ep
a rti
cle s
w
a sd
et
e rm
i
n ed b
y
m ic r o
b i
al
a n al
y
si
sb
ot
h
b
ef
o r e a nd
aft
e r s am p l
e sw
e r e s ub
j
e ct
ed
to
a c e nt
ri ft
ig
at
io n
p
r o c e s sC
e nt
ri f
ug
at
i
o nw
a s sh
ow
nt
o
r em
o v em
o
r et
h
a n9 7 %
of h i g h d
e n si
t y
(
>
2
.5 g/
cm
)
p
a rt
ic
l
e s,w h i le
r et
ain
i
ng
t
h
em
aj
o rit
y
o
f l
ow d
e n sit
y
(
1
.0 5
g
/
cm
')
p
a rt
i
cl
e
st
h
at
w
e r e r ep
r e s e nta
t
iv e
of
"fr
e ep h
a s e "m
ic r o
b i
al
o r
g
a ni
sm
s.St
o rm
s am
p l
e sw
e r e ch
a r a ct
e riz e
d b
y
i
n c r e a s ed m ic r o
b i
al
a nd
p
a rti
cle c o
n
c e nt
r at
i
o n sr e
l
ati
v et
ob
a ck
g
r o u nd
c o nd i
t
i
o n s.T
h
efr
a ct
i
o n of
o rg
a ni
sm
s r em
o v ed
vi
a c e nt
ri f
ug
at
i
o nv a r
i
ed b
y
m i
c r ob
e a nd b
et
w
e e nb
a ck
g
r o u nd
a nd
st
o rm
c o nd i
t
io n s
T
h
eh i
g
h
e st
a v e r ag
er e
m
o v als
w
e r e ob
s e r v ed i
nf
e c al
c ol i f
o rm
s(
2 8% b
a ck g
r o u nd
;
5 8%
st
o rm
)
a nd C I
p
e rf
ri
ng
e n ss
p
o r e s(
4 5%)
b
a ck
g
r o u nd
,6 1%
) st
o rm
)
,w h
e r e a st
ot
al
c ol i p h
ag
ed
em
o n st
r at
ed
t
h
elo
w
e st
r e
m
o v als
(
1
3 %
oi
nb
ot
h b
a ck
g
r o un
d
a nd
st
o rm
c on
d i
t
io n s
)
.P
a rti
cle c o n c e n
t
r at
i
o ni
s c on
si
st
e nt
l
y
h i gh
t
hr o u
g
h
o ut
st
o rm
e v e nt
s,b
ut
p
e ak m ic r o
bi
al
c
o
n c e nt
r at
io n s
t
e
nd
to
v a ry b y
m
i
c r ob
e.F
e c al
c ol i f
o rm
st
e nd
t
ob
eh i gh
e st
a sf lo
w
s a r ein c r e a s
i
ng
,E
c ol
i
c o n c e nt
r at
i
o n ste n
d
t
ob
eh i g h
e st
n e a rp
e ak f
l
ow
s, a nd
e nt
e r o c o c ci
a nd
t
ota
l
i
n
t
r o
d
u c
t i
o n
N
o np
oin
t
s o u r c ew
ate r
p
ol l
ut
io n
is a
w
ate r
q
u al
i
t
y p
r ob l
em
of i
n c r e a sin
g
c o n c e r n .I
t
i
sa
l
e ad i
ng
c
a u s e of w
at
e rp
ol lu
t
i
o ni
nt
h
eU
ni
te
d St
ate s
, a nd
u rb
a n n o np
o
in
t
s o u rc
ep
ol l
ut
i
o ni
sa
m
aj
o rf
a ct
o rin
fr
e sh w
at
e r an
d
e st
u a ry
i m
p
air
m
e nt
(
E
P
A
,2
0 02
)
.T
h
eC l
e a nW
ate r
A
ct
A
m
e nd m
e nt
s of
1
9 8
7
h
a v e s o ug h
t t
o ad d
r e s st
h
ep
r ob
l
em
of
n o np
oi
nt
s o u r c ep
ol l
ut
i
o n,b
ut th
ei d
e nt
i
f
i c at
i
o n a nd
r em
ed i
at
i
o n of
th
e s e s o u r c e sh
a sb
e e nm
u ch m
o r ed i f fi
c ul
t th
an
f
o rp
oin
t
s o u r c e s
(
J
am
e s,2
0 0 3
)
.N
o
np
oin
t
s o u r c e c o nta
m in a n
t
s c a ni
n cl
ud
e s u sp
e nde
d
s ol i d
s a nd
ah
o st
o
f
o rg
a ni
c a nd b i
ol
ogi
c al
c o nt
am i
n a nt
s.O f
p
a rt
i
c ul
a ri
nt
e r e st t
op
ub l i
ch
e al
th
a r et
h
em
i
c r ob
i
al
c o nt
am
i
n a nt
st
h
at
e nt
e rw
at
e r sh
ed
si
n sto r
m w
at
e r r u n of f
.Pa
t
h
og
e n c on t
am i
n at
io n
i
st
h
e s e c o nd m
o st
p
r e v al
e nt
c a u s e of w
ate r
b
od
y
i m
p
air
m
en t
i
nt
h
eU
ni
t
ed St
at
e s,w
it
h
o v e r7
,0 0
0 i m
p
air
m
e nts n a
t
io n
w i d
e(
E P
A
,2
0 0
4
)
St
o rm
e v e nt
s an
d
th
e r e s ult
in
g
r u n of f
c a u s e as u
b
st
a nti
al
p
o rt
i
o n of
t
h
e c o nt
am
i
n an t
l
o ad i
ng
of m i
c r ob i
al
o rg
a nis
m
st
o r e c ei
vin
g
w
at
e r s(
C
r ab i l l
et
al 19 9 8
,N i
x19 9 4
,W
a ni
el is
t
ae
t
al
.1 9 7 7
,W
ei b
el
et
al
.19 64
)
.B
a ct
e ri
al lo
adi
ng
si
nu r
b
a n st
r e am
sh
a v eb
e e nl i
nk
ed
t
oh
o
u si
ng d
e ns
it
y
,p
op
ul
at
i
o n, a nd d
e v el
op
m
e nt
(
Y
o u ng
a nd
T
h
a ck
st
o n19 9 9
)
, a nd
t
h
et
h
r e at
sto
w
ate r
q
u al i
t
y
w
i
l l
c o nt
i
n u et
o ri
s ew i
t
h
u rb
a ng
r ow
t
h
.M
i
c r ob i
al
c o nta
m
in a
t
io n
c a nh
a v ew
i d
e sp
r e ad p
ub
l i
ch
e al
t
h
c o n s eq
u e n c e s,i
n clu
d i
ng
a
dv e r s e
ef f
e ct
s o nd
ri
nk i
ng
w
at
e r, r e c r e at
io n a
l w
ate r
s o u r c e s, aq
u ati
cf
o od
, a nd w
at
e r sh
eds
.R
e c e nt
r e s e a r ch
s ug g
e st
s ap
o s si b l
el i
nk b
etw
e e n r ain
f
al l
r un
of f
a nd
o utb
r e ak
s of w
at
e rb
om
ed i
s e a s e(
C
u r ri
e r o et
al
.2 0 0 1,
R
o s e et
al
.2
0 0 1
)
.S
om
e stu
d i
e sh
a v e ad dr e s s e
d
t
h
ep
o st
-st
o rm
s e
d i
m
e nt
s of
w
ate r
b
od
i
e s,l
e s si
nlo
i ow
n ab
o ut
m
i
c r ob
ia
l b
eh
a vi
o ri
nt
h
ew
at
e rc
ol
um
n a nd
t
h
etr a
n
sp
o rt
p
r o c e s s e sb
y
w h i
ch
m ic r o
b
e sb
e c om
ep
a rt
of
t
h
e s ed
i
m
e nt
I
m
p
r ov
ed
k
n ow
l
ed
g
eo
f m
i
c r ob i
al p
a rt
i
ti
o ni
ng
c a np
r o vi d
e ab
a si
sf
o rb
et t
e r u nde r s
t
an
d
i
ng
t
h
e s et
r a n sp
o rt
p
r o c e s s e sM
i
c r ob i
al
-p
a rt
ic
le
in
t
e r a ct
i
o n s c an
h
a v e c rit
i
c al
ef f
e ct
s o nm ic r o
b
i
al
f
at
ea
nd
t
r a n sp
o rt
.M
i
c r ob
e sm
ay
a s s o ci
ate
w i
t
h p
a rt
ic
l
e si
nt
h
ew
ate r
c ol
um
n o r r em
ai
ni
nth
e "fr
ee
"p
h
a s e.M
i
c r ob
e s a s s o cia
t
ed w i
th
p
a rt
i
cl
e s,p
a rt
i
c ul
a rl
y
h
e a vie r a
n
d /
o ri
n o rg
a nic
p
a rt
ic
l
e s,w i l l
t
e nd
t
os e
t tl
e o ut
of
t
h
ew
at
e r c olu
m
n
m
o r eq
ui
ck l
y
,w h i l
em
i
c r ob
e sin
th
efr
e ep
h
a s em
a
y t
r a v el m
u ch
g
r e at
e rd i
sta n c e sd
ow
n st
r e am
In
ad d it
io n
,m i
c r ob
e s a s s o cia
t
ed w i
t
h
p
a rti
cle s o
f
t
e nt
e nd
t
os u r v
i
v el
o ng
e rin
n at
u r al w
at
e r s(
H
ow
el l
,J
M
et
al
.1 9
9 6
,Sh
e r e r et
al
.1
9 9 2
,B
u
rto n
et
al
1
9 8 7,
G
e rb
a a nd Sc
h
ai b
e rg
e r19 7 5
)
.P
a rt
it
i
o nin
g
of
m
ic r o
b
e st
h
e r ef
o r e af f
e
ct
sn o t
o nl
y
m i
c r ob ia
l f
at
e a nd
tr a n s
p
o rt
i
nt
h
e e n vir o n
m
e nt,
b
ut
al
s
ot
h
el
e ng
t
h
of
t
i m
et
h
e s e o rg
a ni
sm
sr e
m
ain
ap
ot
e nt
i
al
t
h
r e at t
op
ub l i
ch
e al
th
.T
h i
s st
ud
y
ch
a r a ct
e riz e s
t
h
ep
a rt
it
i
o ni
ng
of
s e v e r al
m
i
c r ob i
al
sp
e cie s
(
f
e c al
c ol i f
o rm
s,E
c ol
i
, e nt
e r o c o c ci
,C lo s
tr
i
d
i
um p
e rf
ri
ng
e n s sp
o r e s, a nd
t
ot
al
c ol i p h
ag
e)
i
n u rb
an
st
o rm w
at
e rr u n o
f f b
y
i
n v e st
i
g
at
in
g p
ot
e nt
ia
l l i
nk
sb
et
w
e e nm i
c r ob i
al
c o n c e ntr a
t
io
n
,p
a rt
ic
l
e c o n c e nt
r at
i
o na n
d d i f f
e r e nt
p
a rt
i
cl
e si
z e cla s s e s
.Su c
h
p
a rti
t
i
o nin
g
r el
at
i
o n sh i p
sa
r e e s s e nti
al f
o rm
od
el i
ng
th
el
o c at
i
o n a nd
s e v e rit
y
of w
at
e rq
u al
i
t
y
i m
p
ai
rm
en t
, a sw
el l
a sf
o rd
et
e rm i
nin
g t
h
ee
f f
e ct
i
v e n e s s of
s ed i m
e nt
ati
o n a s at
r e at
m
e nt
st
r ate
gy
(
i
.e.d
et
e nt
i
o nb
as
i
n s)
.M
a ny
c u r r e nt
w
at
e rq
u
al i
t
y
m
od
els
(
e.g
.B A
S
I
N S
)
a s s um
et
h
at
al l
m
i
c r ob
e s a r ein
t
h
e
fr
e ep
h
a s e, an
e r r o ri
nt
h
e c a s e of m
an
y
m i
c r ob
es
t
h
at
im
p
a ct
sw
at
e rq
u al i
t y
est
i m
at
e s.G iv e n
th
at
m
od
el
s a r ec u r r e n
tl
y
ap
ri
m
a ry
m
e a n s of
e v al
u at
i
ng p
e rm
i
t
ap p
l i
c at
i
o n s(
eg
N
at
io n a
l P
ol l
ut
a nt
D i
s ch
a rg
eS
t
o rm w
at
e rM
a n ag
em
e nt
)
, r e s e a r ch
t
h
at
f
a ci l i
ta t
e si
m
p
r ov ed
m
od
el i
ng t
h
r ou g
h
c
o nsi d
e r at
i
onB
a c
k g
r o u n
d
R
e s e a r ch h
a sd
e s c ri b
ed
t
h
ep
a rt
i
t
io n
i
ng
r el
at
io n s
h
i
p
sb
et
w
e e np
a rt
i
cl
e s an d
v a ri
o u sc o n
t
am i
n a nt
si
nt
h
ew
at
e r c ol
um
n,b
ot
h
o rg
a ni
c(
S
t
e n st
r om
et
al
.1
9
8 4
,
H
u nt
e r et
al
.1 9 7 9
)
a nd
in o r
g
a ni
c(
C h
a r a ck l is a
n
d
W
i
es
n e r1
9 9 7
,T
an
iz a
k i
et
al
.19 9 2
)
.H
ow
e v e r,
m
u ch l
e s sw
o rk h
a sb
e e nd
o n et
o ch
a r a ct
e ri
z et
h
ep
a rt
i
t
io n
i
ng
r el
at
io n s
h i
p
s of m i
c r ob ia
l
c o nt
am
i
n a nt
sP
r e vi
o u sp
a rt
ic
l
e-m ic r o
b i
a
l
st
ud ie s
h
a v ef
o c u s ed
o nt
h
e s ed i m
e nt
s r at
h
e rt
h
a nt
h
ew
at
e r c ol
um
n(
Sh
e r e re
t
al
.1
9 9 2
,
B
u rt
o n et
al
1
9 8
7
,L
aB
el l
e a nd G
e rb
a1
9 8
0
)
.W
h
i l
et
h
i
si
nf
o rm
at
io
n
i
si
m
p
o rt
a nt
i
n e v alu a
t
in
g t
h
ep
o s si b l
ei m
p
a ct
s of
r e s u sp
e n si
o n,i
t
i
sl
e s s u s ef
ul fo r
e v al
u at
i
ng p
a rt
i
t
i
o nin
g
i
nt
h
ew
at
e r c ol
um
n
T h i
s
i
si m
p
o rt
a nt
b
e c a u s ei
t
i
st
h
ep
a rt
i
t
i
o ni
ng b
eh
a vio r
i
nt
h
ew
at
e rc o
lu
m
nt
h
at
p
l
ay
s a c ri
t
i
c al
r ol
ei
nd
et
e rm i
ni
ng m i
c r ob i
al f
at
e an
d
t
r an
sp
o rt
.So
m
e st
ud
i
e sh
a v e ob
s e r v ed
a nd
r ep
o rt
ed
e vi d
e n c e of
p
a rt
i
cle
-m ic r o
b ia
l
r e
l
at
i
o n sh
i
p
si
nt
h
ew
at
e r c ol
um
n a nd i
n s ed i m
e nt
s,w i
t
h
at t
en t
io n
u s u al l
y
f
o c u s ed
o nf
e c al
c ol i f
o rm
s.G
e rb
a an
d S
ch
ai b
e rg
e r(
1
9
7
5
)
in
di
c at
ed
t
h
at
b
a ct
e ri
al
c o nt
am
in a
n t
s a s s o cia
t
ew i
t
h
p
a rt
i
cl
e si
n
s
t
o rm w
at
e r r u n of f
, an
d G
a rmo n(
19 8 3
)
i
nd i
c at
ed
t
h
at
s am
p
le s
w i
t
h h i
g
h
t
u rb i d i
t
y
c oin c
i d
ed
w
i
t
h h i g h f
e c al
c ol i f
o rm l
e v els
.O
t
h
e r st
ud i
e sh
a v e ob
s e r v ed p
a rt
i
t
i
o ni
ng
of
vi
r u s e si
nt
h
ew
at
e r c ol
um
n(
G
e rb
a a nd Sc
h
ai b
e rg
e r1
9
7 5
)
a nd
s ed i
m
e nt
s of
e st
u a ri
n e e n vi
r o nm
e nt
s(
L
aB
el l
e a nd G
e rb
a19 8 0
)
,b
ut
vir a
l p
a rt
i
t
io n
i
ng h
a s n ot
b
e e nin v e s
t
i g
at
ed i
nf
r e sh w
at
e rc o n
d i
t
i
o n s.A
l
t
h
o ug h
s om
et
r e nd
sh
a v eb
e e n ob
s e r v ed
,
f
ew
of
t
h
ep
r e vi
o u s st
ud i
e sh
a v eq
u a nt
i
t
at
iv e
l
y
ch
a r a ct
e ri
z ed
t
h
ep
a rt
i
t
i
o ni
n
g
r el
at
i
o n sh i p
sin
am
an
n e r u s ef
ul f
o r e st
i
m
at
i
ng
t
r a n sp
o rt
a nd /
o r r em
o v al p
r o c e s s e s.I
n ad di
t
i
o n,t
h
e r el
at
i
o n sh i p
sb
et
w
e e np
a rt
i
cle s a n
d
ot
h
e rm
i
c r ob
i
al
o rg
a ni
sm
s(
eg E
c ol
i
a nd
e nt
e r o c o c ci
)
h
a v e n ot
b
e e nd
e v elo
p
ed
.C h
a r a ct
e ri
zi
ng
t
h
ep
a rt
i
t
i
o nin
g
of
p
a rt
i
c ula r
m i
c r ob
e st
op
a rt
i
cl
e si
nd i f f
e r e nt
si
z eL
a rg
e r,d
e n s e r(
eg
i
n org
a ni
c)
p
a rti
cl
esw
i l l h
av eg
r e at
er s et t
l i
ng
v el
oci
t
i
e s.M
i
c
rob
e sa
t t
a ch
ed
t
o s u ch
p
a rt
ic
l
e sw i l l
n ot
r em
ain
s u sp
e nd
ed i
nt
h
ew
at
e r c ol
um
n a sl
o ng
a nd
t
h
u sw
i l
l
t
r a v el
sh
o rt
e rla
t
e r al
d i
st
an
c e si
n r e c ei
vi
ng
w
at
e r st
h
a nt
h
o s e a s s o ci
at
ed w
i
t
h
l
e s sd
e n s e(
eg
o r
g
a ni
c)
p
a rt
i
cl
e s o rt h
o s e r em
ain
i
ng
i
nt
h
ef
r e ep
h
a s eA
st
ud y
b
y S
ch i l
l i
ng
e r an
d G
a n n o n(
19 8 5
)
in v e s
t
i
g
at
ed
t
h
ep
o s si b
i l
i
t
y
of
ag
e n e r al
a s s o c
i
at
i
o nb
et
w
e e nf
e c al
c ol i f
o rm
s a nd
p
a rt
i
cle s
.Si
ng
le s
t
o rm w
at
e rg
r ab
s am
p
l
e sw
e r ec o
l l
e ct
ed du r
i
ng
st
o rm
s e v e nt
sfr o
m
a st
o rm dr a
i
n a nd i m
m
ed i
a
t
el
y
an
al
y
z ed f
o rt
u rb i d i
t
y
,s u s
p
e nd
ed
s ol i d
s,t
ot
al
s ol i d
s,f
e c al
co
l i f
o rm
s,K
l
eb
si
el l
ab
a ct
e ria
,P
s e ud
om
o n a sb
a ct
e ri
a, a nd
G
r am
n eg
at
i
v eb
a ct
e ria
.A
s ugg
e st
iv e
p
o si
t
i
v et
r e nd b
et
w
e e nf
e c al
co
l i f
o rm
s a nd
s u sp
e nde
d
s o
l i d
s c o n c e nt
r at
io n s
w
a s ob
s e r v ed i
nt
h
e r aw
s am p l
e s, al
t
h
o ug
h
t
h
et
r e nd w
a s no t
st
at
i
st
ic a
l l
y
s
i g
ni f
i c a nt
.A
p
a rt
i
t
io n
i
ng
r el
at
io n s
h i
p i
s s ug g
e st
ed
b
y
t
h i
sd
at
a,b
u t t
h
e r ew
e r en
od i
r e ct
p
a rt
ic
l
e si
z em
e a s u r em
e nt
s of
t
h
e s u sp
e nd
ed
s ol i d
s.Sa
m
p
l
e sw
e r e c ol l
e ct
ed
a nd
s om
ew
e r es
et
t
le
d
T
h
e s up
e r n at
a nt
of
t
h
e s et t
l
ed
s am
p
l
e sw
a s r em
o v ed
a nd
t
e st
ed f
o rb
a ct
e ri
a.T
h
et
ot
al p
a rt
i
cl
em
a s s of
t
h
e s up
e rn
at
a nt
an
d
s ed i m
e nt
w
a sm
e a s u r ed
.I
nt
h
eb
a ct
e ri
al
s am p l
e s,16
.8
%
of
t
h
ef
e ca
l
c ol i f
o rm
s,3 3
%
of
t
h
eK l
eb
si
el l
a,a n
d 3
1 1
%
of
t
h
eP
s e ud
om
o n a s et t
l
ed
o ut
of
t
h
e s am p
l
e sI
n
g
e n e r al
,t
h
eK l
eb
si
el l
a a nd
P
s e ud
om
o n a sb
a ct
e ria s e
t
t
le
d
t
o ag
r e at
e r e xt
en
t t
h
an
fe c a
l
c ol i f
o rm
s.T h
e se
r e su
l
t
s su
gg
e st
ed
t
h
at t
h
ed
eg
r e e of
m
i
c r ob i
al
p
a rt
i
t
i
o ni
ng
m
ay
v a ry
b
y
o rg
a ni
sm
v e r
y
sm
al l
p
a rt
i
cl
e s)
B
e c a u s ep
a rt
i
cl
e
s a nd m i
c r ob
e s sm
a
l l
e rt
h
a n5
|
Lim
c o ul
d
h
a
ve
b
ee
nr e
t
ai
n ed b
y
t
h
ef
ilt
e r c ak
et
h
at
b
ui l d
s up
d
u
ri
ng
f
ilt
r at
i
o n,th
ef
r a ct
i
o n e xi
st
i
n
g i
nt
h
ef
r e ep h
a s em
ay
h
a v eb
e e n u nd
e r e st
i
m
at
ed T h
e st
ud
y
al
s o n ot
ed
t
h
at t
h
e sh
e a r st
r e s s e s a s s oc
i
at
ed
w
i
t
h
t
h
es
m
al l
e rfi l
t
e r s c r e e n c o ul d h
a v e c a u s ed
p
r ob l
em
sw i
t
h
t
h
ed
at
a.B
a ct
e ri
al p
a rti
t
i
o ni
ng h
a s al
s ob
e e n e xp
l
o r ed i
n a c o n st
r u ct
ed w
et
l
a nd
a nd
aw
at
e rp
ol l
ut
i
o n c o nt
r ol
p
o nd
sy
st
em
(
D
a vi
e s a nd
B
a v o r,2
0 0 0
)
.A
n al
y
si
sw
a s c om
p
l
et
ed f
o rp
r e s um
p
ti
v et
h
e rm
ot
ol
e r a nt
c ol i f
o rm
s, e nt
e r o c o c ci
,t
ot
al h
et
e r ot
r op
h i
c
b
a ct
e ri
a,a n
d
C l
o st
ri
d
i
um p
e rf
ri
ng
em
sp
o r e sI
nf l
ow
an
d
o ut
fl
ow w
at
e r s am
p
l
e sw
e r e c ol l
e ct
ed w
e ek l
y
S
ed i m
e nt
a nd w
at
e r c ol
um
n s am p l
e sw
e r e c ol l
e ct
ed
o n c e.T h
ep
a rt
i
cl
e si
z ed i
st
ri b
uti
o n of
t
h
es e
d i m
e nt
s am
p
l
e sw
a sd
et
e rm
i
n ed
u si
ng t
h
ep
i
p
et t
em
et h
od
(
t
h
ep
a rt
i
cl
e si
z ed i
st
ri b
ut
i
o n of
th
ew
at
e r c ol
um
nw
a s n ot
c o n si d
e r ed
)
.A
s et
of
c ol
um
n e xp
e ri m
e nt
sw
e r e c o nd
u ct
ed w i
t
h
t
h
e s es e
d i m
e nt
s r e s u sp
e nd
ed
i
nd
ei
o ni
z ed w
at
e r.F
o rt
h
ep
i
p
et t
em
et
h
od
, s et t
l i
ng
v el
o ci
t
i
e s,d
e ri
v ed
v
i
aSt
ok
e s'L
aw
,w
e r e u s ed
t
od
et
e rm i
n eth
e s am
p
l i
ng
ti
m
ef
o r e a ch
of
t
h
e si
x si
z efi
-a c
t
i
o n s(
f
o r at
ot
al
p
a rt
i
cl
e r a ng
e of
<
2
^
m
t
o>
6 2
f
xm
)
at
a c e rt
ai
nd
ep
t
h i
nt
h
e s am
p l
eT h
e s ed i m
e nt
sw
e r e r e s u sp
e nd
ed i
nd
ei
o ni
z ed w
at
e r a nd
al l
ow
ed
t
o s et t
l
e,w i
t
h
s am p l
e s a cq
ui
r ed
at
sp
e ci f
i ed
t
i m
e sb y
p
i
p
et
t
e at t
h
e s et
d
ep
th
.T h
e st
ud y
c o n cl
ud
ed
t
h
at
t
h
eb
a ct
e ri
aw
e r ep
r ed
om i
n an t
l y
a
d
s o rb
ed
t
ofi
n e cl
ay p
a rti
cl
e s(
l
e s st
h
a n2
\
im i
nd i
am
et
e r)
.H
ow
e v e r , si
n c e r e su
sp
e nd
ed
s e
d i m
e nt
sw
e r e u s ed
t
op
e rf
o rm
th i
s a n al
y
si
s,t
h
ein
i
t
i
al b
eh
a vi
o ri
nth
e
w
at
e r c ol
um
nw
a s n ot
d i
r e ct
l
y
i
n v e st
i
g
at
ed
.T h
e s ep
r e vi
o u s st
ud i
e sh
a v ef
o c u s ed
o ng
r ab
s am
p
l
e sto
ch
a r a ct
e ri
z e st
o rm
e v e nts
.S
ch i l l i
ng
e r a nd G
a nn
o n c ol l
e ct
ed
s am
p
l
e s at
p
e ak fl
ow
, an
d D
a vi
e s a nd
B
a v o r co
l l
e ct e
d
m
i
c r ob i
al
c o n c e nt
r at
i
o n s, n ei
t
h
e r e xp
l
o r ed h
ow m i
c r ob
i
al
c o n c e nt
r at
i
o n s a nd p
a rt i
t
i
o ni
ng
b
eh
a vi
o rm i
g
h
t
ch
a ng
et
h
r o ug
h
o ut
a st
o rm
e v e nt
.R
e s e a r ch i
nd i
c at
e st
h
ed i f f
i c ul
t
y
i
n ch
a ra
ct
e ri
zi
ng
a "t
y p
i
c al
"s
t
o rm
(
F
i
el
d
et
al
.19 93
,
Q
u r e sh i
a nd
D
ut
k
a1 9 7 9
,W
ei b
el
et
al
.1 9 6 4
,W
an
i
el i
st
a et
al.
19 7
7
,G
el d
r ei
ch
et
al.
19 6 8
)
.V
a ri
ati
o n si
n c o nt
am
i
n a nt
c o n c e nt
r at
i
o n s an
d
r e c ei
vi
ng
w
at
e r ch
a r a ct
e ri
sti
cs
a r ea
f
un
ct
i
o n of
p
r e-s
t
o rm
c o nd i
t
i
o n s(
e.g
.t
i
m
e si
n c el
a st
st
o rm
)
, s
t
o rm d
u ra t
i
o n, st
re
am f l
ow
,w
a t
e rt
em
p
e r at
u r e, a nd
oth
e r sit
e ch
a r a ct
e ri
st
i
c s.T h
ef
i r st
f l
u sh
r ef
e r st
oth
ef
i r st
p
o rti
o
n of
s
t
o rm w
at
e rt
h
at
en t
e r s aw
at
e rb
od
y
a nd
i
s oft
e nth
o ug h
t t
oh
a v et
h
em
aj
o ri
t
y
of
m
i
c r ob
i
al
c o n
t
am i
n an t
s a s s o ci
at
ed w it
h
t
h
e st
o rm
e v e nt
.Q
u r e sh i
a nd
D
u t
k
a(
19 7 9
)
d
et
e rm
i
n ed
th
at
p
e ak
c o n
t
am i
n an t
c o n c e nt
r at
i
o n s c a n v a ry
c o n si d
e r ab l
y
a nd
a r e n ot
n e c e s s a ri l
y
f
o u nd i
nt
h
ef
i r st
f l
u sh
.N
o
ap
p
a r en t
l i
nk
sb
et
w
e e np
e ak f l
ow
a nd
th
eo
c c u r r e n c e of p
ea
k m i
c r ob i
a
l p
op
ul
at
i
o n sw
e r e ob
s e r v ed
.D
u
et
oth
e ch
a ng
e si
np
a rti
cl
e an
d m i
c r ob i
al
c o n c e nt
r at
i
o n st
h
r ou
g
h
o ut t
h
ed
u r at
i
o n of
a st
o rm
e v e nt
,i
t
m
ay
b
em
o r e ap
p
r op
ri
at
et
o u s e a c om
b in
at
i
o n of
sin
g
l
eg
r ab
s a
m
p l
e s a nd
s am
p
l
e s c ol l
e ct
ed
o v e rth
eh
y
d
r og
r ap
h
(
i
nt
r a-s
t
o rm
s am
p l
e s)
t o
p
r ov
i d
e am
o r ea c c u r a
t
em
e a n s of
ch
a r a ct
e ri
zi
n
g
t
h
et
ot
al
m i
c r ob i
al l
o ad f
r om
a st
o rm
e v e nt
.E
a rl i
e r st
ud i
e sh
a v et
ak
e ni
nit
i
al
st
ep
si
nd
e v el
op
i
ng t
h
e r el
ati
o
n sh i p
sd
e s c ri b i
ng
b
a ct
e ri
al
-p
a rt
ic
l
ei
nt
e r a ct
i
on
si
n st
o rm w
at
e r.B
ot
h S
ch i l l i
ng
e r a nd G
an
n o n(
19 8 5
)
a nd D
a vi
e sa n
d B
a v o r(
2 0 0 0
)
h
a v e s ug g
e st
ed
t
h
at
a c o n si d
e r ab l
ef
r a ct
i
o n of b
a ct
e ri
a a s s o ci
at
ew it
h
s u s
p
e nd
ed
p
a rt
i
cl
e s,b
ut
q
u a nt
i f
i c at
i
o n of
th
e s e r el
at
i
o n sh i
p
si
s st
i l l l
a ck i
ng
.I
n ad d i
ti
o n,th
ei m
p
r o vi
ng
e st
i
m
at
e s of
m
i
c r ob
i
al
t
r an
sp
o rt
a nd
d
et
e rm
i
ni
ng
t
l
i e ef f
e ct
i
v en
e s s of
st
o rm w
at
e rM
e
t h
o
d
s
3
.1 S i
t
e
S
e
l
e c
t
i
o n
S
am
p l
e sw
e r e c ol l
e ct
ed f
r om
t
h
r e el
o c at
i
o n s :E
n oR
i
v e r,M
e et
i
ng
of
t
h
eW
at
e r sC
r e ek
,a n
d B
o ok
e rC
r e ek
, ai l i
n a nd
a r o u nd
C h
ap
el
H i l
l
an
d D
u rh
am
,N
o rth C
a r ol i
n aB
o ok
e rC
r e ek
a n
d
M
e et
i
ng
of
t
h
eW
at
e r sC
r e ek f l
o
w i
n
t
oJ
o rd
an
L
ak
e,w h i
ch
t
h
e nf l
o
w
si
n
t
ot
h
eC
ap
eF
e a rR i
v e r.T
h
eE
n oR i
v e rf l
ow
si
nt
oF
al l
sL
ak
e,w h i
ch
t h
e nf l
ow
si
nt
ot
h
eN
e u s eR i
v
e r.Si
t
e sw
e r e s el
e ct
ed
t
ob
e r ep
r e s e nt
at
i
v e of d i f f
e r e nt
t
y p
e s of l
a nd
u s e.S
am
p
l
e sf
r om
t
h
eE
n oR
i
v e rw
e r e c ol l
e ct
ed
at t
h
eG
u es
sR
o ad
c r o s si
ng
of
t
h
e ri
v e r.T h
e s u r r o u nd i
ng
l
an
d i
s cl
a s si f
i ed
a sl
ow d
e n si
t
y
r e si d
e nt
i
al
.T h
e
r ei
s aU S G S
g
ag
e st
at
i
o nd
ow
n st
r e am
at t
h
eSR 5 0 1
c r o s si
ng
of
t
h
e ri
v e r, an
d
t
h
eT
ow
n of D
u rh
am
al
s o c ol l
e ct
sw
at
e rq
u al i
t
y
d
at
a at t
h i
sl
o c at
i
o n
M
e et
i
ng
of
t
h
eW
at
e r sC
r e ek w
a s s am
p
l
ed
at t
h
eb
ri dg
el
e ad i
ng
t
ot
h
e e nt
r a n c et
ot
h
eO
r a ng
eW
at
e r a nd
S
ew
e rA
ut
h
o ri
t
y
(
O
W
A
SA
) M
a s o nF
a rm R
o ad
W
a st
ew
at
e rT
r e at
m
e nt
P l
a nt
T h i
sl
o c at
i
o nw
a s up
st
r e am
of
t
h
eO
W
A
S
A d i
s ch
a rg
e.T
h
el
a nd
u s ei
s cl
a s si f i
ed
a sp
ri m
a ri l
y
i
n st
i
t
ut
i
o n al
; t
h
eU
ni
v e r si
t
y
of N
o
rt
h C
a r ol i
n a at
C h
ap
el H i l l i
s up
st
r e am
.W
at
e rq
u al i
t
y
i
sm
o ni
t
o r ed m
o nt
h l y
at
t
h i
sl
o c at
i
o nb
y
t
h
e
T
ow
n of C h
ap
el H i l l
a nd
aU S G S g
ag
es
t
at
i
o ni
sl
o c at
ed
j
u st
d
ow
n st
r e am
.B
o ok
e rC
r e ek
w
a s s am
p
l
ed
at
W
i l l
ow D
ri
v e,d
ow
n st
r e am
of
t
h
eE
a st
g
at
eSh
op p
i
ng
3
.2 S
a
m
p l
e
C
o
l l
e c
t
i
o n
Sa
m
p
l
e sw
e r e c ol l
e ct
ed
i
nb
a ck g
r o u nd
(
dr
y
)
a nd w
et
w
e at
h
e r c o nd
i
t
i
o n s,w i
t h
b
a ck
g
r o un
d
c o nd i
t
i
on
sd
ef
i n ed
a s at
l
e a st
t
h
r e ed
ay
sw i
t
h
o ut
app
r e ci
ab l
ep
r e ci
p
i
t
at
io n
S
t
o rm
s a
m
p
l i
ng
e v e nt
sw
e r e ch
a r a ct
e riz e
d b
y
at
le a s
t t
h
r e ed
ay
sw i
t
h
o ut
ap p
r e ci
ab l
e r ai
n
f
al l b
ef
o r et
h
e e v e nt
a nd
a ni
n c r e a s ei
n st
r e am
f l
ow
of
at
l
e a st
f
o u rt
i
m
e sp
r e-st
o rm fl
ow
.
A
l l
s am
p
le s
w
e r e c ol l
e ct
ed i
n rin s e
d
n ew
, st
e ri l
e c ub i
t
ai
n e r s.Sa
m
p
le s
w
e r e c ol l
e ct
ed i
nd
up
l i
c at
ef
o rq
u al i
t
y
c o nt
r ol
an
d
r ep
r odu c
i b i l i
t
y p
u rp
o s e s.Sa
m
p
le s
w
e r e ob
t
ai
n ed
ei
t
h
e rb
y
w
ad in
g
in
t
ot
h
es
t
r e am
a nd
s ub m
e rg
in
g
t
h
e c on
t
ai
n e ri
nt
h
e st
r e am w
at
e r, o rb
y
l
ow
eri
ng
ab
u ck
et
in
t
ot
h
es
t
r e am
w
h
e nt
h
ew
at
e rl
e v el
o rb
ri d
g
eh
ei
g
h
t
w
o ul d
n ot
al l
ow f
o rw
ad i
n
g
.W
at
e rt e
m
p
e r at
u r ew
a s r e c o rd
ed
at t
h
et
i
m
e of
s am
p
l i
n
g
a nd
p H
w
a sd
et
e rm
i
n
ed i
n t
h
ela
b
o r at
o ry
(
A
c c um
et
1
0
p
H m
et
e r)
A
f
t
e r s am
p
l
e sw
e r e c ol l
e ct
ed
,t
h
ey
w
e r e st
o r ed i
n c o ole r s
w i
t
h i
c ep
a ck
s an
d
t
r a n sp
o rt
ed
t
ot
h
el
ab
o r at
o ry
f
o ri m m
edi
at
e a n al y
si
s.D
u rin
g d
ry w
e at
h
e r,b
a ck g
r o u nd
g
r ab
s am
p l
e sw
e r e c ol l
e ct
ed
.F
o rw
et
w
ea
t
h
e rs a
m
p
l
e s,4
-6
s
t
o rm
sw
e r e ch
a r a ct
e ri
z ed b y
si
ng
l
eg
r ab
s amp l
e s(
d
ep
e nd in
g
up
o n sa
m
p
l i
ng
si
t
e)
a n
d
1
st
o rm
w
a s ch
a r a ct
e ri
z ed
b
y
in
t
r a-st
o rm
s am
p
l in
g
(
at t
w
o si
t
e s)
.T h i
si
nt
r a
-s
t
o rm
s a
m p l i
ng
c o n si
st
ed
of 5
-6
s a
m p l
e st
ak
e n o v e ra
2
4
-h
o u r
p
e rio
d
t
o a n al y
z et
h
e c on
d i
t
io n s o v e r
t
h
eh
y
d
r og
r ap
h
3
.3 S
a
m
p
l
e
P
a r
t
i
t i
o n
i
n
g
C
e nt
ri f
ug
at
io n
w
a s u s ed
t
o r em
o v ep
a rt
ic
l
e s a nd
a s s o ci
at
ed
m
i
c r ob
e sf
r om
s
u sp
e n si
o n .Co n
t
r ol
e xp
e rim
e nt
s(
Se c
t
i
o n3
.5
)
ch
a r a ct
e riz e
d
t
h
ed
eg
r e et
ow h i
ch
c e nt
ri f
ug
at
io n
r em
o v e st
h
el
a rg
e r a nd/
o rd
e n s e rp
a rt
ic
l
e s.B y
u sin
g
c e nt
ri f
ug
at
i
o n,m i
c r ob i
al
an
d
p
a rt
i
cl
ep
a rt
i
cl
e-m
i
c r ob i
al p
a rt
i
t
i
o ni
ng b
eh
a vi
o rC
e nt
ri
f
ug
at
i
o n r at
h
e rt
h
a nf
i l
t
r at
i
o nw
a su
s ed b
e c au
seo
f
t
h
ep
ot
e nt
i
al
p
r ob
l
em
s of
cl
og g
i
ng
t
h
ef
il
t
e r s o r sh
e a ri
ng p
a rt
i
cl
e s(
S
ch i l l i
ng
e r a nd G
a n n on
,19 8
5
)
O
n c et
h
e s am
p l
e sw
e r e r et
u r n ed
to
t
h
el
ab
o r at
o ry
, an
y
m
at
e ri
al
t
h
at
m
ay
h
a v e s et t
l
ed
d
u ri
ng
t
r a n sp
o rt
w
a s r e s u sp
e nd
ed b y g
e nt
l y i
n v e rt
i
ng
e a ch
c ub i
t
ai
n e rt
h
r e et
i m
e s.A
p
o rt
i
o n of
e a c
h
s am
p
l
e(
c ub i
t
ai
n e r)
w
a s c e nt
ri f
ug
ed i
n1 L
a ut
o cl
a v ed
c
e ntr
i f
ug
eb
ot t
l
e s.A S
o
r v al l R C
-
3
H
-6
0 0
0 A C
e ntr
i f
ug
ew
a s u s ed
t
o s ep
a r at
et
h
e s am
p
l
e si
nt
ot
h
et
w
o si
z ef
r a ct
i
o n s.T h
ec e n
t
ri f
ug
ew
a s r u n at
1
1
6 4
xg
(
2 00 0
rp
m
)
f
o r10 m i
n ut
e sw i
t
h
ab
r ak
eo
f 4 w h i l
e at
em
p
e r at
u r e of
4
°C w
a sm
ai
nt
ai
n ed
.O
n c e c e nt
ri f
ug
at
i
o nw
a s c om
p
l
et
e, ap
p
r o xi m
ate
l
y 7
0 0
m
L
of
su
p
e r n at
a nt
f
r om
e a ch
c e n
t
ri f
ug
eb
ot t
l
ew
a s r em
o v ed
.T h
e ap p
a r at
u s u s ed
t o
r em
o v et
h
ew
at
e rf
r om
t
h
e ce
nt
ri f
ug
eb
ot t
l
e s c o n si
st
ed
of
a v a c u um fl
a sk w i
t
h
ah
o s e c o nn
e ct
ed
t
o ap
i
p
et t
et
h
at
t
h
at
d
r ew w
at
e r o ut
o
f
t
h
e c e nt
ri f
u
g
eb
ot
t
l
e a nd i
nt
o t
h
efl
a sk
T h
eb
o r e of
t
h
e5 m L p i
p
et
te
w
a s e nl
a rg
ed
at
b
ot
h
e n
d
st
o c r e at
e aw i d
e r ap
e rtu r e a n
d l i
m
i
t
p
a rt
i
cl
eb
r e ak
up
f
r om
sh
e e rf
o r c e s.T h
ep
i
p
et t
et
i
p
w
a sk
ep
t
j
u st
un
d
e rt
h
ew
at
e r s u rf
a c e o nt
h
e ed g
e of
t
h
eb
ot
t l
e a st
h
ew
at
e rw
a sw
i
t
h d
r aw
nT h
e s am p l
e sf
o rp
a
rt
i
cl
e a n al y
s
i
sw
e r ep
ut
i
n1 L
s am
p l
eb
ot t
l
e st
h
at
h
ad b
e e nw
a sh
ed
w
i
t
h
t
ap
w
ate r
t
h
r e et
i m
e s a nd d
ei
o ni
z ed
w
at
e rt
h
r e et
i m
e sT h
e s am
p
l
e sf
o rm
i
c r ob i
al
an
al
y
si
sw
e
r ep
ut
i
n1 L
a ut
o cl
a v ed
s am p l
eb
ot t
l
e sA f
t
e r r em
o v al
, al l
r aw
a nd
c e ntr
i f
ug
ed
s am
p
l
e sw
e r esto r e