Risk Assessment

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Risk Assessment
Effects Assessment
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Analysing risks
HOLISTIC whole ecosystem chemical
soup Problems extrapolating to other soups /
ecosystems what is causing the problem? Benefits i
mpact on whole ecosystem identification of
dangerous sources

• TRADITIONAL
• single chemical
• single species
• single compartment
• Problems
• extrapolating to other species
• are there mitigating effects in real world?
• Benefits
• direct quantifiable data
• knowledge of dangerous chemicals

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Analysing risks

• Exposure
• rate of emission
• rate of loss
• rate of transformation
• rate of dilution

Effects acute vs chronic individual vs
population direct vs indirect
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Effects analysis

• Considerations
• at what concentration would you become
  concerned? This is called the concern
  concentration.
• What endpoint are you going to measure
• - death, illness, any noticeable effect?
• - short term acute, or long term chronic?
• how do you cover the breadth of species diversity
  in any ecosystem?

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Median Effect Levels
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Sodium hypochlorite tox (Daphnia)
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Some measurement abbreviations

• NO(A)EC No Observed (Adverse) Effect
  Concentration
• LO(A)EC Lowest Observed (Adverse) Effect
  Concentration
• EC-XX Effect concentration that exhibit XX
  response
• LC-XX Lethal effect concentration for XX of
  population
• LD-XX as above but for Lethal Dose (ie feeding)
• LT-XX as above, stands for Lethal Toxicity

100
50
killed
0
Dose
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LC Definitions
100
50
mortality
10
0
Dose
Notes LC-10 lt LC-50 lt LC-90 LC-0
NOEC(mortality)
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EC and NOEC Definitions
100
90
50
effect
10
0
Dose
Notes EC-10 lt EC-50 lt EC-90 EC-0 NOEC
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Data for NaClO
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LC-50 data
Mean 2.74 (550 mg/L)
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EC-50 data
Mean 2.49 (310 mg/L)
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NOEC LOEC Data for NaClO
Mean 1.99 (98 mg/L)
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What you are after

• Generally, the concern concentration will be
  set somewhere around the 95 confidence interval
  for the NOEC concentration.
• Do a statistical analysis to find this.

What happens if you dont have enough data for
sensible statistical analysis?
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Extrapolation by use of Uncertainty Factors
(UFs)
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Extrapolation by use of Uncertainty Factors
(UFs)
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Extrapolation by use of Uncertainty Factors
(UFs)
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Class Exercise

• You are each given a subset of the NaClO data
  from previously.
• Use the extrapolation factors to derive a concern
  concentration from the data.
• Compare with the concern concentration from the
  full dataset.

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PRV Predation Vulnerability PSE
Photosynthesis PSR Population Size Redn PTR
Phototactic Response PUP Pupation REP
Reproduction RES Respiration RGN
Regeneration RSD Residue SHD Shell
Deposition SPR Secondary Production SRE Whole
System Resp. STR Stress SVC Shell Valve
Closure TER Teratogenesis THL Thermal TMR
Tumour VTE Vertebral
CODE EFFECT ABD Abundance ABN
Abnormality ASM Assimilation Efficiency AVO
Avoidance BEH Behaviour BGC Biogeochem.
Processes BIO Biochemical BMS Biomass CAL Case
Leaving CEL Cellular CLR Chlorophyll CYT
Cytogenetic DEC Decomposition DET
Detachment DIV Species Diversity DRF Drift DVP
Development EMR Emergence ENZ Enzyme EQU
Equilibrium FLT Filtration Rate
FOC Food Consumption GPR Gross Primary
Productivity GSI Gonadosomatic Index HAT
Hatchability HEM Hematological HIS
Histology HMG Hemorrhage HPS Hepatosomatic
Index HRM Hormone IMM Immobilization LOC
Locomotor Behaviour MIG Migration MOR
Mortality MUL Multiple Effects NFX Nitrogen
Fixation OXC Oxygen Consumption PCC Pop.
Carrying Capacity PGR Population Growth PHY
Physiological PIG Pigment POP Population PRB
Predatory Behaviour PRP Primary Productivity
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