Uptake of Dietary PCBs by Rainbow Trout

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Uptake of Dietary PCBs by Rainbow Trout

• Robert F. Carline and Patrick M. Barry
• Penn. Coop. Fish Wildlife Res. Unit
• U.S.G.S. and Penn State University
• H. George Ketola
• U.S.G.S Tunison Lab. Aquatic Science

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Background

• 1998 PCBs discovered in PA state trout hatcheries
• 1999 PCB concentrations exceed states
  consumption advisory limits
• PCB concentrations varied among hatcheries

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Background

• 1999 Low concentrations of PCBs in fish feeds
• Feeds meet FDA standard, lt200 ppb

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Objectives

• 1. What is the relation between concentrations
  of PCBs in fish feed and concentrations in trout
  fillets?

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Objectives

• 2. Of the PCBs consumed by trout, what
  proportion is assimilated ?

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Objectives

• 3. If PCBs are present in hatchery supply water,
  what are the relative contributions of PCBs from
  the water and from the feed to the total found in
  trout?

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Feed Formulations (Aroclor 1260 added)
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Sampling PCBs in water

• Semi-permeable membrane device (SPMD)
• Flattened polyethylene tubing
• 91 cm long by 2.5 cm wide
• 0.9 grams of triolein (purified lipid)

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Experiments

• 6-month trial 4 diets
• 3-week assimilation trial 4 diets

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6-Month Trial

• 4 diets
• 3 tanks of trout per diet
• Monthly sampling
• Food
• Fish
• Water (SPMDs)

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• PCB and lipid analyses conducted by Battelle
  Laboratories, Duxbury, Mass.
• Aroclor 1254/1260 standard

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Initial Trout Size

• 124 mm total length (SD 5.9)
• 22.6 grams (SD 3.8)

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6-Month Trial Final Sizes
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Objectives

• 2. Of the PCBs consumed by trout, what
  proportion is assimilated?

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Assimilation Study

• Add chromic oxide to feed 1 by wt.
• Feed fish for 2 weeks
• Strip feces
• Analyze feces for PCBs and chromic oxide

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Assimilation Experiment
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Objectives

• 3. If PCBs are present in hatchery supply water,
  what are the relative contributions of PCBs from
  the water and from the feed to the total found in
  trout?

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SPMD Deployments

• 3 in source spring and 3 in tank with no fish
• Replace monthly

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12-Month Average

• Source Spring
• 293 ng PCB/SPMD
• Inside Tank
• 200 ng PCB/SPMD

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Mass Balance Approach

• Initial Body Burden of PCBs
• PCB uptake from feed
• Expected Body Burden of PCBs

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Actual body burden of PCBsminus Expected
body burden of PCBsUptake of PCBs from water
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Diet 2 Month 1
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24 Monthly Comparisons

• 8 comparisons Actual gt Expected
• Uptake from water
• 16 comparisons Expected gt Actual
• No evidence of uptake from water
• Overall Average difference 8.8, meaning on
  average, no evidence of uptake from water

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Summary

• PCB concentrations in fillets were positively
  related to PCB concentrations in feed
• With feed that had 126 ppb PCBs, concentrations
  in fillets after 6 months did not exceed advisory
  limit of 100 ppb

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Summary

• PCBs were detected in the source water and there
  was no indication that the hatchery
  infrastructure contributed additional PCBs to the
  water
• Preliminary analyses suggest that uptake of PCBs
  from water was not important

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Summary

• PCB uptake was primarily from the feed and trout
  assimilated a large a large proportion (87) of
  PCBs in the feed