Possible scenarios and
risk assessment
for activities involving substance that may
be released into water paths in case of
accidents
Minsk, 2121-22 October 2008
Possible scenarios and risk
assessment
Industrial activities
Several industrial activities handle dangerous
substances which are generally kept under
control inside process equipment.
In case of
Loss of containment
Fire,
Fire, explosion
explosion and
and toxic
toxic Liquid
Liquid release
release in
in water
water
release
or
release in
in atmosphere
atmosphere
or in
in soil
soil
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Industrial activities
Liquid release in water body
HAZARDS
Release of dangerous substance
may cause damage to:
Animal life
Sources of potable/industrial
waters;
Fishing activities;
Bathing activities.
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Estimate of potential
consequences
Liquid release in water body
Consequences of accidental
release in water can be
calculated as combination of
Toxicological
property of the
dangerous
substance
Maximum
releasable amount
of dangerous
substance
Workshop on: “Training on identification of hazardous
activities”
activities”
Vulnerability of
the territory
surrounding the
release point
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Estimate of potential
consequences
Toxicological property of the dangerous substance
Lethal
Lethal Concentration
Concentration
LC50aq/1
LC50aq/1 hr
hr =
= 0,8
0,8 mg/lit
mg/lit
Main pollutants are classified
according to their potential
impact on aquatic life.
Cl
Effects are
evaluated in terms
of concentration
of dangerous
substances in
water.
Cl
Chlorine
Chlorine
Workshop on: “Training on identification of hazardous
About
About 0,8
0,8 mg/lit
mg/lit of
of chlorine
chlorine
dissolved
into
water
dissolved into water is
is capable
capable
to
to cause
cause the
the death
death of
of yellow
yellow
perch
perch (or
(or other
other common
common
fishes)
after
fishes) after 11 hour
hour of
of
exposure.
exposure.
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Estimate of potential
consequences
Toxicological property of the dangerous substance
LC50aq
aq
Concentration of dangerous substance leading to
death for 50% of a selected aquatic specie for a
specified time of exposure.
Data are produced with laboratory tests.
Data might be taken from:
ƒ Material Safety Data Sheet of the substance;
ƒ Specialised international Data Banks.
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Estimate of potential
consequences
Max releasable amount of the dangerous substance
Large storage tanks
(i.e.
(i.e. oil
oil storage
storage tanks
tanks of
of aa refinery)
refinery)
Oil
Oil spill
spill can:
can:
•• reach
reach immediately
immediately the
the water
water body
body (see
(see
picture).
picture).
•• Reach
Reach the
the sewer
sewer network
network and
and be
be
subsequently
subsequently released
released into
into the
the water
water
body.
body.
Underground tanks
(i.e.
(i.e. liquid
liquid storage
storage at
at chemical
chemical plant)
plant)
Liquid
Liquid spill
spill can
can percolate
percolate into
into the
the soil
soil and
and
reach
reach surface
surface or
or under
under ground
ground water.
water.
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Estimate of potential
consequences
Max releasable amount of the dangerous substance
Maximum Releasable Amount
corresponds at least to the entire
volume of tank of maximum capacity
Mitigation elements:
Basin for
containment
Sewer
network
Workshop on: “Training on identification of hazardous
Water treatment
plant
activities”
activities”
Floating
strips
Minsk, 2121-22 October 2008
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4
Possible scenarios and risk
assessment
Estimate of potential
consequences
Vulnerability of territory surrounding release point
Industry
Town
Commercial
centre
River
Fishery
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
Pag.
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Possible scenarios and risk
assessment
Estimate of potential
Liquid release in water body
consequences
Consequences
Consequences
Toxicological
Toxicological
property
property
Max
Max
releasable
releasable
amount
amount
Vulnerability
Vulnerability
Combination of three functions can be
very complex and require detailed
information:
Technical data from the site (process, protection systems, etc.);
Emergency organization of the site;
Toxicological data of substances;
Detailed data on water courses (flow rate, variability during year, etc.)
Detailed data on sensible activities (towns, fisheries, etc.)
The
The analysis
analysis might
might require
require aa long
long time
time to
to be
be completed.
completed.
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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5
Possible scenarios and risk
assessment
iffiieedd
mpplli chh
S
Siim
oaac
aapppprro
Estimate of potential
Liquid release in water body
consequences
Gravity of consequences is expressed as
Volume of water endangered by toxic
substance
1 kg of
chlorine
Endangered
volume
V (m 3 ) =
V (m 3 ) =
Q( g )
mg
LC50 ( )
lit
1000( g )
= 1250m 3
mg
0,8( )
lit
One
One bottle
bottle of
of chlorine
chlorine is
is sufficient
sufficient to
to endanger
endanger an
an entire
entire swimming
swimming pool
pool of
of 25
25
m
m of
of lenght.
lenght.
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
Pag.
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Possible scenarios and risk
assessment
iilleedd
D
Deettaa acchh
oa
aapppprro
Estimate of potential
Liquid release in superficial water body
consequences
w1
Dangerous
substance
Q
t1
Q = released amount (g)
wi = mean flow rates
(m3/s)
w2
Ti = mean times to cover
distances (s)
t2
w1+w2
t3
w3
Workshop on: “Training on identification of hazardous
w1+w2+w3
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
iilleedd
D
Deettaa acchh
oa
aapppprro
Estimate of potential
Liquid release in superficial water body
consequences
Ci
Ci == mean
mean concentration
concentration of
of
dangerous
dangerous substance
substance
(mg/l)
(mg/l) in
in the
the rivers.
rivers.
C3
C3 == mean
mean concentration
concentration of
of
dangerous
dangerous substance
substance
(mg/l)
(mg/l) close
close to
to
vulnerable
vulnerable target.
target.
Q
C1
Dangerous
substance
C2
C3
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
Pag.
Pag. 13
Possible scenarios and risk
assessment
iffiieedd
mpplli chh
S
Siim
oaac
aapppprro
Estimate of potential
consequences
Liquid release in underground water body
Main
Main risk
risk associated
associated to
to aa release
release
of
of dangerous
dangerous substance
substance in
in the
the
soil
soil the
the contamination
contamination of
of
Q
QGW
GW
Groundwater
Basic
Basic Concepts:
Concepts:
) reaches
•• Of
Of the
the total
total released
released amount
amount (Q)
(Q) only
only aa fraction
fraction (Q
(QGW
GW) reaches
groundwater
groundwater due
due to
to soil
soil permeability
permeability and
and reactivity;
reactivity;
) is directly
•• The
The volume
volume of
of endangered
endangered groundwater
groundwater (V
(VGW
GW) is directly
associated
associated to
to amount
amount of
of dangerous
dangerous substances
substances reaching
reaching the
the
).
water
).
water table
table (Q
(QGW
GW
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
Pag.
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7
Possible scenarios and risk
assessment
Estimate of potential
Liquid release in water body
consequences
iffiieedd
mpplli chh
S
Siim
oaac
aapppprro
Q
Q
Gravity of consequences is expressed as
Volume of water endangered by toxic
substance
VGW (m 3 ) =
Q
QGW
GW
QGW ( g )
mg
LC50 ( )
lit
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
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Possible scenarios and risk
assessment
Neil
Workshop on: “Training on identification of hazardous
activities”
activities”
Minsk, 2121-22 October 2008
Pag.
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