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MALACCA STRAITS
Name: Poon Tsz Ha, Wendy
Fu, Vivian
TF Tse
Presentation Outline
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Background of the project
Methodology of the project
Data Analysis
Recommendations
Purpose
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Demonstrate ERA – risk management
as a viable framework for managing
land- & sea-based sources of marine
pollution in subregional sea areas
Packaging the approach, methods &
experience for the similar environmental
management in E Asian region
MALACCA STRAITS
Background Information
Unique ecological system
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High productivity & diversity
Rich mix of fauna & flora
Intricate hydrodynamics
Complex interactions within & between
water body & land-based activities
Geography
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Natural channel
between Indian &
Pacific Ocean
Bounded by 3
littoral States
2nd busiest
shipping lane in
the world (300
vessels/day)
Source:
http://en.wikipedia.org/wiki/Strait_of_Malacca
Geography
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Euryhaline condition
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Rich nutrient level
Shelter from strong currents & wave action
High & uniform temperature
Adequate tidal flushing
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High biological productivity & diversity
Rich mix of fauna and flora from Indian &
Pacific Ocean
Natural biological resources
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Mangrove: 80% at Indonesian side
Seagrass bed: patchy and abundant
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Nursery grounds for many fish species
Shows relationship between availability of
habitats, fish stocks & sustainable yield
Corals: patchy but not very abundant
Natural biological resources
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Exploited along both coasts of the Strait
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Fisheries for demersal & pelagic species:
NW half of the Strait
Mangrove removal for timber &
aquaculture : entire length
Extensive aquaculture: cause potential
problem to environment through release of
organic waste & chemicals
Population & Employment
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Indonesia: 11m; predominant on
agriculture & fisheries, derivative
industries based on natural resources
Malaysia: 10m; mix of agriculture,
fisheries, heavy & light manufacturing
industries
Singapore: 3m; manufacturing &
commercial activities
River system
Similar numbers of river catchments on
Indonesian & Malaysian coasts
 Similar amount of rainfall
 Similar volume (90million m3)of
outflows & runoffs from both coasts
(presumption)
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Sewage facilities & Quality of
inputs
Area
Sewage facility
Quality of inputs
Indonesia
very limited
agricultural
Malaysia
limited
industrial
Singapore
very complete
industrial
Impacts to the Strait
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Increase of total suspended solids in the
water column & sedimentation
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Mangrove removal (esp. NW half of Strait) 
increase erosion
River load
Agricultural runoff
Aquaculture
  O2 depletion, light attenuation &
physical cover  impacts on mangroves,
seagrass beds & corals
Impacts to the Strait
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Volume: 1012 m3
Considerable dilution & removal of
contaminant loads by flushing
Dominant surface movement: SE to NW
Temperature and its impacts
Constant high temperature (26 – 30。C)
 Exposure side:  rate of biodegradation
 contaminants
 Effect side:  rate of contaminant
High level of metabolism
(Ecotoxicological effect)
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Rainfall and its impacts
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High intensity but Short duration
Considerable contamination of dissolved and
particulate materials from storm water runoff
Reduce in salinity  Osmotic stress in marine
species   contaminant exposure
Reduce in salinity  Alter bioavailability of
many contaminant (e.g.  Cd   fraction
of dissolved metal exits as free ions)
MALACCA STRAITS
Methodology
Target
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Human health
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Habitat
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Fish / seafood consumption
Contamination of fish / seafood by metals,
pesticides & hydrocarbon
Mangroves, peat swamps, seagrass beds, coral
reefs, soft-bottom habitats
Species
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Commercial & non-commercial marine species
Addressing the questions
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Evidence for problems with human
health, habitats & species (incl.
commercial fish stocks)
Problems caused to human health,
habitats & species by conditions exist
now or in the future
Identify assessment &
measurement Endpoint
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Risk = f(H)(E)
Where: H = Potential harm
E = Likelihood of exposure to
potential harm
2 stages of risk assessment
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Initial risk assessment
Refine risk assessment
Initial risk assessment
Screening mechanism: identify priority
environmental concern on a Strait-wide basis,
related data gaps & uncertainties
Objective:
 Utilize available information on sources,
exposure & effect of land- & sea-based
activities, and pollution derived therefrom on
living & non-living resources
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Program outline for initial risk
assessment
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Preparation of draft report
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Major polluting sources & activities, and
their effects on living & non-living
environment
Delineation of the significant indicators of
ecological, human health & social risk from
pollutive land- & sea-based activities
Spatial & temporal scales of assessment
Program outline for initial risk
assessment
1. Preparation of draft report (cont)
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Interaction between land- & sea-based
activities and interactions with living &
non-living resources in & along the Straits
Combine effects of multiple & diverse
stress on ecology
Systematic effect of a catastrophic event,
e.g. oil / dangerous chemicals spillage by
shipping accident
Program outline for initial risk
assessment
2. Identify data gaps & uncertainties that
need comprehensive risk
characterization
3. Formulation of action plan for
comprehensive risk assessment
Utilize available expertise & resources to
develop risk management program for
the subregion
Refine risk assessment
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The Strait as a whole
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The Strait as a single compartment and
estimate a single average exposure
concentration for the entire Strait)
Selected contaminants, risk to local
areas within the Strait
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Local exposure concentration in the vicinity
of specific human activities or natural
resources
Refine risk assessment
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Complete refined risk assessment of
land- & sea-based sources of pollution
& their effects on living & non-living
resources
Using results of initial risk assessment &
updated information from the 3 littoral
states to produce a comprehensive
document on ERA
Program outline for refined risk
assessment
1. Review & analyze available data provided,
update and/or verify the methodologies,
conclusions & recommendation of initial risk
assessment
2. Model development & demonstration of
series of scenarios. Analysis of scenarios
3. Test techniques for improving uncertainty
analyses and report the results
Others
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Uncertainty assessment
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Qualitative & quantitative method
Society risk
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Environmental degradation & its impact to
the economy
Risk-benefit analysis
Prioritize risk assessment in the society, as
a key in risk management
Consideration
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Relation between potential causes of
problems for human health and the
environment
Consequences in the Strait
Analysis of risk pathways: high
economic importance, incl. social,
national, governmental commercial
interests
Consideration
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Sources of hazards related to economic
Knock-on effects to economy by pollution
Influence judgment about priorities for action
 Direct risk assessment  Weigh benefits
to human health and the environment with
costs to economy Influence management
actions taken
MALACCA STRAITS
Risk Assessment
Approaches of risk assessment
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Retrospective risk assessment
Prospective risk assessment
Retrospective risk assessment
Key ingredients
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Identifying targets and endpoints precisely
Identifying significant adverse changes
 Evidences to show the problems
Identifying possible causes of the
changes
Identifying possible consequences of the
changes for ecosystems and human
welfare
Key ingredients
In this paper:
 Evidences of decline on the Straits
 Habitats
 Biodiversity
 Attributed causes
 Based on expert judgment and weight of
evidence rather than experimental sciences
 Possible consequences
Habitat loss and consequences
Habitat
 in
Areal  in
Consequences
extent quantity quality
Ecological Economic
Mangroves
L
L
M
***
**
Peat swamps
L
L
NI
***
**
Coral reefs
S
NI
M
**
*
Seagrass beds M
NI
M
**
*
Soft bottoms
No
M
**
**
L
Habitats - Mangroves
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Evidences of decline
 Sumatra (Indonesia): loss 24% of
mangrove coverage in 7 years (19871993)
 Malaysia: loss 17% of mangrove
coverage in 2 decades (1965-1985)
 Singapore: loss approximately 81% of
mangrove coverage in the last 2
decades
Habitats - Mangroves
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Attribute causes
 Clearance for brackish water ponds
 Over-exploitation for timber and charcoal
 Clearance for development
 Sedimentation and pollution
Consequences
 Reduced protection from coastal erosion and natural
disaster
 Reduced nursery grounds for commercial and noncommercial fish and invertebrates
 Loss of habitat for endangered species
 Economic loss for the timber industry
Habitat: Peat swamp forests
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Evidences of decline
 Sumatra (Indonesia): 7.3-9.3 million
hectares to 3.6 million hectares (50%
reduction)
 West coast of Peninsular Malaysia:
299,145 hectares (77% of this area are
indicated as “disturbed and loggedover”)
Habitat: Peat swamp forests
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Attribute causes
 Logging of commercially valuable tree
species
 Land conversion to rice, palm and
coconut plantations
Consequences
 Loss of biodiversity
 Similar to the consequences of the loss
of mangrove coverage
Habitat: Coral reefs
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Evidences of decline
 No data on the total area of coral reefs in the
Straits and the loss of coral reef area
 Indonesia:
 Poor condition: 42%; Fair condition: 29%;
Good condition: 24%; Excellent condition: 5%
 Malaysia:
 Most of the coral reefs are rated as fair
condition
 Singapore:
 Among the most stressed in Asia coral reef
Habitat: Coral reefs
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Attributed causes
 Fishing damage
 Pollution e.g. metals, oil spills and pesticides
 Massive land reclamation in Singapore
Consequences
 Reduced in physical protection of shorelines
 Loss of biodiversity
 Reduced in fishery production
 Loss of tourist attraction
Habitat: Seagrass beds
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Evidences of decline
 No quantitative data on areal coverage or its loss
 Singapore: Extensive seagrass beds  Isolated
patches
 50 known seagrass species
 Indonesia:12 species
 West coast of Peninsular Malaysia: 9 species
 Singapore: 9 species decline to 7 species(1990s)
Habitat: Seagrass beds
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Attributed causes
 Destruction due to the conversion to coastal
aquaculture
 Natural disaster e.g. storm and disease
 Deposits of mining spoils and tailings
 Excessive sediments due to deforestation Pollution
Consequences
 Loss of buffering zone from wave action
 Reduced stabilization of sediment
 Reduced in biodiversity
 Loss of harvestable invertebrates, macroalgae and
grass
 loss of nursery grounds for fishes
Habitat: Soft-bottom habitats
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Evidences of decline
 Straits: covered by sandy and muddy bottom
extensively
 * Quality in supporting species
 An examination of effects on female
reproductive systems in gastropods in
terms of percent female imposex
 Negative correlations between females with
imposex and distance to the nearest
shipping route
Habitat: Soft-bottom habitats
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Attributed causes
 Physical disruption by trawling
 Contamination of sediments from
pollutants
Consequences
 Loss of tourism attraction e.g. sandy
beach
 Decline for fisheries production
Biodiversity
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Assessment endpoint: population
density and species diversity
Biodiversity
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Evidence of decline on on-commercial
species
 Population density: Two indigenous fish
species (Alosa toil and Lactarius lacarius)
are getting rare in Singapore
 Species diversity: 52 species of fish, 13
species of coral and anemones, 12
specie of crustaceans – extinct; >50
other species – threatened in Singapore
Biodiversity
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The increasing deterioration of
environmental conditions in the Straits and
increasing human activities result in
changes of species composition
(disappearance of other species and the
increasing number of endangered species)
Biodiversity
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Attributed causes
 Loss of major habitats
 Contamination
Consequences
 Loss of tourist attraction
 Increase in instability of the ecosystem
Biodiversity
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Evidences of decline on commercial
species:
 Indonesia: Decline in catch-per-uniteffort (CPUE)
 Malaysia: fall in total catch and catch
rate
Biodiversity
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Attribute causes
 Over-fishing
 Losses of nursery grounds
 Pollution
Consequences
 Economic loss
 Reduction of fish species
Prospective risk assessment
Prospective risk assessment
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Identify the likely problems for harm to
ecological
Scientific and objective measurement
 Risk quotient
Risk quotient
 Provide indices of risk for further
detailed analyses
Risk Quotient (RQ)
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Measurement
 RQ = PEC / PNEC
 RQ = MEC / STD
Certain substances that occur naturally i.e.
background concentrations
 BQ = MEC / background concentration
Uncertainty analysis
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Carried out for the prospective risk assessment to the
varying levels of sophistication
PNECs and STDs
 Depend on the reliability of the ecotoxicological
and toxicological data
MECs
 Depend on the reliability of sampling and
analytical techniques
PECs
 Depend on the assumptions of the models used in
making predictions and the reliability of input data
Prospective risk assessment
In this paper
 Estimate the likelihood of adverse effects
from environmental conditions within the
Straits
 By comparing measured environmental
concentrations (MECs) and predicted
environmental concentrations (PECs)
Likely problems for harm to
ecological
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Various heavy metals in the water and
sediment
Pesticides in the water and sediment
Problems arising from suspended solids
Concentration of heavy metals in
water
Metal
As
Highest RQ (table RQ
BQ
7-3)
(Danish std) (MEC/BV)
mean
MEC
8
0.08
/
8
Cd
114
11
46
28500
Cr
62
0.12
/
413
Cu
34
0.34
11.7
567
Hg
68
68
227
136000
Pb
108
1
19
108000
Concentration of heavy metals in
water
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RQ analysis
 RQ > 1 = High risk
 Metals of Pb, Hg, Cd and Cu >1
 Results of BQ is consistent with RQ
Concentration of heavy metals in
water
Uncertainty analysis
 Variability among standards
 Purpose for use
 Variability in MECs
 Values above or below the critical value (Log
RQ = 0)
 Data of RQ have to be transformed and
presented as mean log value
 Log RQs for all metal > 0
Concentration of heavy metals in
water
West Coast of
Peninsular Malaysia
Metal Highest
RQ
mean PEC (Danish std)
Zn
0.334
0.004
Klang River
Highest
mean PEC
/
RQ
Cu
2.6
0.9
25.8
9.9
Hg
0.0007
0.0002
/
/
Pb
0.404
0.007
0.089
0.016
(Danish
std)
/
Concentration of heavy metals in
water
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Klang River
 Greatest density of manufacturing
industry along the west coast of
Peninsular Malaysia
 Heavy Metal contamination in coastal
waters was limited to certain areas close
to industrial sites and estuaries
Concentration of heavy metals in
sediments
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No general accepted sediment quality standards
RQ estimation
 Based on water quality
 Csed = (Cw X Ksw) / r
 Critical concentration of metal in sediment =
(concentration of metal in water X solids-water
partition coefficient) / empirically derived
concentration ratio between suspended matter
Concentration of heavy metals in
sediments
MetalsCd
As
Cd
Cr
Cu
Ni
Pb
Zn
RQ (table 7-3)
0.0400
0.0060
0.0007
0.0700
0.0030
RQ
(Danish std)
0.03
0.36
2.40
2.10
0.06
0.07
Concentration of heavy metals in
sediments
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Lack of concordance between water column and
sediment data
 The water and sediment samples were taken
from different sites
 Different metals were included in the 2 types
of analysis
 Periodically dredged of sediment
 Dissolved and particle-bound form of
sediments
Heavy metals and human
health
RQ = daily metal intake / tolerable daily
intake (TDI)
 Daily metal intake = daily intake X metal
content of the intake
 Level of concern (Action level) = Tolerable
daily intake / Seafood consumption
 Likely problems for harm to ecology and
human
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Heavy metals and human
health
Uncertainty analysis
 Uncertainty in tolerable daily intakes
 TDIs standard varies between countries
 Dermal exposure to metal e.g. bathing
Conclusion
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Retrospective Risk Assessment
Decline in mangroves, peat swamp forests,
coral reefs, seagrass beds and soft bottom
habitats
Mainly caused by habitat destruction such as
coral reef were affected by increased
sediment loads
Reduction in fish stocks due to overfishing
Pollution was probably a contributory factor
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Prospective Risk Assessment
Various heavy metals were found in water
column and sediment, pesticides
TBT or nutrients were not identified
Human Health Prospective Risk
Assessment
No indication that health problems might
arise from oil and hydrocarbon exposure
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Oil and Hydrocarbon Pollution
Long term exposure
– land based industrial activities
Short-term exposure
– accident was calculated on the basis of
historical experience
MALACCA STRAITS
Recommendations
Recommendations
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General Recommendations
Standards used in future risk assessment
should be agreed by all littoral States
E.g. definition of ecological targets on
both scientific and societal issues
E.g. definition of thresholds (standards
and PNECs)
General Recommendations
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Regional monitoring programs should be available
for future risk assessments
Exposure models should be developed for future
risk assessment.
Needs in human health risk assessment to reduce
the uncertainties with both threshold effect
values and exposure information
Recommendations to Risk
Management
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agreement on the approach between
littoral States to mangrove clearance
controlling fishing intensity
food contamination monitoring from
metals and pesticides should be
considered
Recommendations to Risk
Management
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prevention of the exposure on the most
contaminated beaches to avoid sewage
infection
Management strategies should be more
proactive to reduce the potential for
contact between high risk vessels and
vulnerable habitats
Risk Management Actions
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Retrospective Assessment
The loss of mangroves, peat swamps
and seagrass beds
The declining fishing
Protection of other species
Risk Management Actions
Prospective Analysis
 Immediate action on RQs greater than
1000
 Food contamination from metals and
pesticides deserves serious attention