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Application of Biomarkers and Application of Biomarkers and BioindicatorsBioindicatorsfor Marine Environmental Monitoringfor Marine Environmental Monitoring
EAS Congress 2009
Doris W.T. AURudolf S.S.Wu, Paul K.S. Shin
City University of Hong Kong
Manila
Outline• What is biological monitoring? and
Why bother?• Application of biomarkers and
bioindicators for different management purposes
• Successful examples in coastal ocean monitoring
Molecules
OrganellesCells
TissuesOrgans
Organisms
Levels of
Biological O
rganizatio
n
CommunitiesEcosystems
Organ systems
Biochemical
Populations
Minutes / Hours Days Months Years
Time until manifestation
Environmental stresses
Bio-monitoring : Use biological responses at different biological organization levels (biomarkers and bioindicators) to indicate significant environmental changes
Application of integrative biomarkers for ERA
Adam 2003
• Biomarkers are biological responses at lower levels of biological organization (molecular, biochemical and physiological responses) that can provide direct evidence of exposure to stressors
relatively sensitive (short-term response) to stressors, serves as early warning indicators of impaired organism health.
• Bioindicators are biological responses at higher levels of organization (individuals, populations, communities)
relatively insensitive (long-term response) to stressors but have higher ecological relevance
• Chemicals may exist in different forms, while bioavailability and toxicity varies considerably with different chemical forms
• Presence ≠ available ≠ effect ≠ adverse effects• Interaction of chemicals (additive, synergistic or
antagonistic) may be important yet difficult to determine
• Major problems exist in assessing or predicting biological effects from chemical / physical data
Bio-monitoring : Why bother ?
Chemical vs Biological monitoring Strength & Weakness
Chemical Monitoring
• Bioavailability not known• No indication of biological effects• Large variations with time• Indirect interpretation of results• Costly and laborious in sampling• Lower Conc., making analysis
difficult
• Comparable between locations/regions
• Accurate• Continuous measurement is
normally easy• More established techniques
Biological Monitoring
• Indicates bioavailability• Provides clues for biological effects• Time integration built in• Direct interpretation of results• Less expensive and easier• Higher conc., making analysis easier
• Different biota may not allow direct comparison of results
• Less accurate• Continuous measurement difficult
• Less established
1. Identify exposure to certain chemicals2. Monitor spatial and temporal changes in pollution 3. Provide early warning to environmental
deterioration4. Indicate occurrence of adverse ecological
consequences.
Biological indicators developed for different management purposes
In the last two decades, a number of biological indicators have been successfully developed and adopted by various national and international marine pollution monitoring programs in North America, Europe, Australia and New Zealand (e.g. NOAA, USEPA, ICES, WFD, OECD, OSPAR, Mussel Watch)
1. Identify exposure to certain chemicals
• Brain acetycholinesterase(AChE) activity for neurotoxic pesticides
• Liver EROD / CYP1A enzyme activity for PAHs/PCBs
Cl
Cl Cl
Cl
P
OO
SNH2
CH3
CH3
Methamidophos
B(a)P
Enzyme assay
organophosphate pesticides, carbamates
1. Identify exposure to certain chemicals
• Vitellogenin for endocrine disruptive compounds (EDCs)
• Metallothionein for metals
Cu-metallothionein Zn-metallothionein
DNA Adducts, DNA Strand Breakage• Indicates levels of genotoxicants in water• Can be measured by alkaline unwinding assay or single cell gel
electrophoresis (Comet assay)
1. Identify exposure to certain chemicals
Body Burden of Metals & Trace Organics• Indicates time-integrated values of bio-available fractions of metals
and trace organics in the environment
The “Mussel Watch” program
2. Monitor spatial and temporal changes in pollution
0
200
400
86 87 88 89 90 91 92 93
DDTPCB
PAH
DDTPCBPAH
Data from O’Connor & Beliaeff (1995)
Annual means of trace organic in mussels at 154 sites in coastal waters of USA
Fish Pathology• Indicate general quality of the environment, and related to
contamination levels of heavy metals, PAHs, PCBs and DDT
Fin erosion Skeletal deformities Skeletal deformities
Liver tumorEpidermal hyperplasia / papilloma
3. Provide early warning to environmental deterioration
Lysosomal Integrity of Mussels• Indicate pollution-induced stress on mussels• Measured by neutral red assay• Used in biomonitoring programs in Europe and USA (e.g. NOAA,
ICES, MED POL, North Seas, WHO-FAO, Hong Kong)
3. Provide early warning to environmental deterioration
Imposex in Marine Snails• Change of sex from females to males (imposex) indicate levels of
tributyl tin (TBT, an antifouling chemical) • Highly sensitive (threshold: 0.5 ng/L in water or body burden of 10
ng/g)• Easy to determine, quantified by e.g. % imposex, relative penis
size, etc
CH2CH2CH2CH3
SnCH3CH2CH2CH2 CH2CH2CH2CH3
Cl
3. Provide early warning to environmental deterioration
e.g. Changes of species diversity
Gymnodinium
eutrophic
4. Indicate occurrence of adverse ecological consequences
Mesodinium
Community Indicators• Indicate general “health”
of a community– Species richness – Species diversity (H’)– Evenness ( J)– Dominance– Similarity – SAB (Species, Abundance,
Biomass) curves– ABC (Abundance Biomass
Comparison) plot– Multivariate statistics
Skeletonema
A Case study in Hong Kong
Review of 53 bioindicators
13 selection criteria
13 Shortlisted bioindicators
Identify informationgap
Field & Lab validations
13 Selected bioindicators
A US$1.1 M study commissioned by
Environmental Protection
Department, Hong Kong
2001-03
I. Identify exposure to certain chemicals1) EROD, (Ethoxyresourufin-O-deethylase) in fish liver
II. Monitor spatial and temporal changes in pollution2) Body burden of metals and trace organics in barnacles and mussels
III. Provide early warning to environmental deterioration1) Fin erosion of fish2) Epidermal hyperplasia/papilloma of fish3) Condition Factor (CF) of fish4) Hepatosomatic Index (HSI) of fish5) Gonadosomatic Index (GSI) of fish6) Lysosomal integrity of mussels7) Imposex of gastropods
IV. Indicate occurrence of adverse ecological consequences1) Diversity indices2) Log normal distribution3) ABC (Abundance Biomass Comparison) plots4) Multivariate statistics of species composition
The 13 selected biomarkers/bioindicators
Development of a cumulative Index
• Integrate different measures at different biological scales to provide an overall message (good for laymen)
• Rapid evaluation by users of the state of the ecosystem
• Provide early warning of changes• Can be used to make quantitative spatial and
temporal comparisons
Integration of measures into a single index
d j = Σ S iji= 1
n
d j = cumulative index for zone jS ij = weighted score for zone ji = measure ( 1….n)
Conclusion• Many biological indicators have been successfully used
in a cost-effective way in N. America, Europe, Australia and New Zealand, including Hong Kong
• However, applications of bio-monitoring in Asia have been extremely limited
• High national priority should be accorded to adopt and validate the use of these bio-indicators in the local seas, so as to improve the cost-effectiveness and environmental relevance of the current monitoring programs in the region
Selection Criteria
1. Ecological relevance2. Ecological importance3. Sensitivity4. Specificity5. Dose-response
relationship6. Reproducibility7. Confounding factors
8. Representativeness9. Scale of applicability10. Easy to understand11. Overseas experience12. Technical difficulty13. Cost-effectiveness