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MALACCA STRAITS. Name: Poon Tsz Ha, Wendy Fu, Vivian TF Tse. Presentation Outline. Background of the project Methodology of the project Data Analysis Recommendations. Purpose.

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Name: Poon Tsz Ha, Wendy

Fu, Vivian

TF Tse

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Presentation Outline

  • Background of the project

  • Methodology of the project

  • Data Analysis

  • Recommendations

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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

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Background Information

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Unique ecological system

  • High productivity & diversity

  • Rich mix of fauna & flora

  • Intricate hydrodynamics

  • Complex interactions within & between water body & land-based activities

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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)


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  • Euryhaline condition

    • Rich nutrient level

    • Shelter from strong currents & wave action

    • High & uniform temperature

    • Adequate tidal flushing

      • High biological productivity & diversity

      • Rich mix of fauna and flora from Indian & Pacific Ocean

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Natural biological resources

  • Mangrove: 80% at Indonesian side

  • Seagrass bed: patchy and abundant

    • Nursery grounds for many fish species

    • Shows relationship between availability of habitats, fish stocks & sustainable yield

  • Corals: patchy but not very abundant

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Natural biological resources

  • Exploited along both coasts of the Strait

    • 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

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Population & Employment

  • 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

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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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Impacts to the Strait

  • Increase of total suspended solids in the water column & sedimentation

    • 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

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Impacts to the Strait

  • Volume: 1012 m3

  • Considerable dilution & removal of contaminant loads by flushing

  • Dominant surface movement: SE to NW

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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

  • 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)

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  • Human health

    • Fish / seafood consumption

    • Contamination of fish / seafood by metals, pesticides & hydrocarbon

  • Habitat

    • Mangroves, peat swamps, seagrass beds, coral reefs, soft-bottom habitats

  • Species

    • Commercial & non-commercial marine species

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Addressing the questions

  • 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

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Identify assessment & measurement Endpoint

  • Risk = f(H)(E)

    Where: H = Potential harm

    E = Likelihood of exposure to potential harm

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2 stages of risk assessment

  • Initial risk assessment

  • Refine risk assessment

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Initial risk assessment

  • Screening mechanism: identify priority environmental concern on a Strait-wide basis, related data gaps & uncertainties


  • 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

  • Preparation of draft report

    • 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

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Program outline for initial risk assessment

1. Preparation of draft report (cont)

  • 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

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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

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Refine risk assessment

  • The Strait as a whole

    • 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

    • Local exposure concentration in the vicinity of specific human activities or natural resources

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Refine risk assessment

  • 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

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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

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  • Uncertainty assessment

    • Qualitative & quantitative method

  • Society risk

    • Environmental degradation & its impact to the economy

    • Risk-benefit analysis

    • Prioritize risk assessment in the society, as a key in risk management

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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

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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

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Risk Assessment

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Approaches of risk assessment

  • Retrospective risk assessment

  • Prospective risk assessment

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Key ingredients

  • 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

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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

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Habitats - Mangroves

  • Evidences of decline

    • Sumatra (Indonesia): loss 24% of mangrove coverage in 7 years (1987-1993)

    • Malaysia: loss 17% of mangrove coverage in 2 decades (1965-1985)

    • Singapore: loss approximately 81% of mangrove coverage in the last 2 decades

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Habitats - Mangroves

  • 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 non-commercial fish and invertebrates

    • Loss of habitat for endangered species

    • Economic loss for the timber industry

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Habitat: Peat swamp forests

  • 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 logged-over”)

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Habitat: Peat swamp forests

  • 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

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Habitat: Coral reefs

  • 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

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Habitat: Coral reefs

  • 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

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Habitat: Seagrass beds

  • 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)

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Habitat: Seagrass beds

  • 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

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Habitat: Soft-bottom habitats

  • 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

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Habitat: Soft-bottom habitats

  • Attributed causes

    • Physical disruption by trawling

    • Contamination of sediments from pollutants

  • Consequences

    • Loss of tourism attraction e.g. sandy beach

    • Decline for fisheries production

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  • Assessment endpoint: population density and species diversity

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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

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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)

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  • Attributed causes

    • Loss of major habitats

    • Contamination

  • Consequences

    • Loss of tourist attraction

    • Increase in instability of the ecosystem

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  • Evidences of decline on commercial species:

    • Indonesia: Decline in catch-per-unit-effort (CPUE)

    • Malaysia: fall in total catch and catch rate

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  • Attribute causes

    • Over-fishing

    • Losses of nursery grounds

    • Pollution

  • Consequences

    • Economic loss

    • Reduction of fish species

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Prospective risk assessment

  • Identify the likely problems for harm to ecological

  • Scientific and objective measurement

    • Risk quotient

  • Risk quotient

    • Provide indices of risk for further detailed analyses

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Risk Quotient (RQ)

  • Measurement

    • RQ = PEC / PNEC

    • RQ = MEC / STD

  • Certain substances that occur naturally i.e. background concentrations

    • BQ = MEC / background concentration

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Uncertainty analysis

  • 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

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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)

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Likely problems for harm to ecological

  • Various heavy metals in the water and sediment

  • Pesticides in the water and sediment

  • Problems arising from suspended solids

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Concentration of heavy metals in water

  • RQ analysis

    • RQ > 1 = High risk

    • Metals of Pb, Hg, Cd and Cu >1

    • Results of BQ is consistent with RQ

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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

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Concentration of heavy metals in water

  • 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

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Concentration of heavy metals in sediments

  • 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

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Concentration of heavy metals in sediments

  • 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

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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

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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

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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)

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General Recommendations

  • 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

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Recommendations to Risk Management

  • agreement on the approach between littoral States to mangrove clearance

  • controlling fishing intensity

  • food contamination monitoring from metals and pesticides should be considered

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Recommendations to Risk Management

  • 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

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Risk Management Actions

Retrospective Assessment

  • The loss of mangroves, peat swamps and seagrass beds

  • The declining fishing

  • Protection of other species

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Risk Management Actions

Prospective Analysis

  • Immediate action on RQs greater than 1000

  • Food contamination from metals and pesticides deserves serious attention