Transcript Delayed, chronic, and indirect effects of shoreline oiling

Part 3: Chronic effects
of decade-long
contamination of key
shoreline habitats and
indirect interactions
are important
Delayed, chronic, and indirect effects of
shoreline oiling/treatment
• Treat EVOS as an ecosystem
perturbation
• Capitalize on vast research
effort
• Synthesis focused on
shoreline habitats
• Contrast of NRDA based on
old ecotoxicity risk models
vs. field-based sampling
What is different about the Exxon
Valdez oil spill?
• $100 million into post spill research
• Low background
contamination
• Isolated
environment
Limitations of old dogma underlying
ecotoxicity risk assessment
• Based solely on shortterm acute toxicity in lab
• Typically assesses only
one mechanism (eg,
exposure to WSF –
water-soluble fraction)
• Treats species as
independent, not linked
through food web or
habitat responses
Limitations of old dogma underlying
ecotoxicity risk assessment
•Extrapolates from few lab-rat
species to species taxonomically
similar but potentially different in
ecology and physiology
•Includes no effects of chronic
exposure, delayed impacts, or
interactions among species
•Includes no sub-lethal impacts on
growth, development, or
reproduction – all of which can
translate to population
consequences
Field sampling approach
• Employs statistical sampling design
• Integrates responses across all
mechanisms
• Includes effects of chronic exposure
and delayed impacts on long time
scales
• Includes interactions of oil and
other stressors
• Includes indirect interactions from
trophic cascades, habitat
modifications, etc.
Implications for
NRDA
• Omission of indirect, chronic, delayed effects
in ecotoxicity risk models amounts to a large
understatement of oil spill impacts
• Predictive ability of such subtle effects by
ecological science lies far in the future,
although some strong interactions can be
confidently predicted
New implications for OPA `90
[Oil Pollution Act of 1990]
• Heavy reliance on bioassay-based acute risk assessment
paradigm of the 1970’s grossly underestimates injury
•Absence of chronic effects assessment also
underestimates recovery times
•Need for agreement among RP (spiller) and government
trustees limits field assessments
•Incentives for quick settlement prevent study of chronic
impacts
•Unexpected impacts also overlooked
Implications for responsible oil use
• Baseline monitoring by independent scientists of sensitive
and risk-prone habitats and resources should be required
•Long-term monitoring needed by independent parties
•Costs should be shared fairly among all users of oil, not
externalized to be borne by the public or public trust
New implications for water quality and
stormwater regulations
• Water quality standards need to be based on
chronic exposure to weathered oil and PAHs
– toxic effects ~ 1 ppb
– prudent safety margin will lower
standard to < 0.1 ppb
•Highway runoff alone produces 1
EVOS annually per 50 million people
•Urbanized estuaries under chronic
pollution stress from PAHs in
stormwater – Phase II EPA rules
Broader policy implications of new oil
ecotoxicity paradigms
• Not just large oil spills but also
numerous small spills and releases
into urban stormwater are important
concerns
• Input to energy conservation policies
• Input to energy source policies
• Input to energy transportation and
waste disposal policies (eg, tanker
transport risk, ballast water disposal)