Lecture 11

Question 1

what are the measurement endpoints for the shorthorn sculpin?

Answer 1

1) literature toxicity data = establish a threshold value for ‘risk’ to reproduction and survival
2) mixed function oxygenase (MFO) induction
3) body morphology

Question 2

what were the results of MFO induction?

Answer 2

• 26-fold greater in the beach area compared to reference sites
• clear evidence of altered liver enzyme activity

Question 3

what are the results for sculpin testing in saglek bay?

Answer 3

1) literature suggests significant adverse reproductive effects in the range of 1000-5000ng/g
2) geometric mean tissue PCB concentration among beach sculpin was 2660 ng/g
3) based on the sediment-sculpin PCB relationship established for exposure assessment, the PCB concentration associated with this sculpin exposure is ~750 ng/g (dry weight)

Question 4

what were the measured endpoints of the black guillemot (an upper trophic level species)?

Answer 4

• multiple endpoints: MFO induction, thyroid activity, growth, immune function, etc.
• results interpreted in dose-response manner: ‘dose’ = measured PCB concentration, ‘response’ = measured endpoint response
• only strong and statistically significant responses were used to characterize risk

Question 5

what were the results for black guillemot testing in saglek bay?

Answer 5

adverse effects of PCBs on:
- immune function and thymus mass
- sex hormones in blood and gonad development
- retinoid (vitamin A levels)
- liver mass
for BG, the ERA identified a lower sediment threshold of 77-355 ng/g dry weight

Question 6

what were the conclusions of the ERA at saglek bay?

Answer 6

• sediment contamination poses a significant risk to ecosystem health
• 2 indicator species showed adverse effects
• definition of ERZ based on site specific criteria (77ppb and 40m water depth)

Question 7

what was the management decision for saglek bay?

Answer 7

allow natural ecosystem recovery to take place and continually evaluate the effectiveness of the recovery

Question 8

what are the results of evaluating biological recovery at saglek bay over the 8 year period?

Answer 8

• shorthorn sculpin: mean liver PCB concentrations have dropped 5-fold
• black guillemot: mean liver concentrations have dropped 20-, 6- and 2-fold at the 3 sites, significant decrease in nestling and egg PCB concentrations in the beach group