mike johns, phd...mike johns, phd toxicology consultant to san diego unified port district. item no....
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Mike Johns, PhD
Toxicology Consultant to
San Diego Unified Port District
Sufficiency of DTR
• RWQCB considered information typical to sediment investigations
• Analysis is consistent with acceptable practice• Would do some analysis differently
– Fisher exposure includes catching fish outside site – Consider inclusion of additional polygon– Additional analysis of another polygon
Beneficial Uses
Exposure pathway conceptual model
Water
Sediment
Spotted Sand Bass FisherShipyard Site
Shipyard sediment concentrations are high
Copper
Tributyltin
Mercury
Shipyard chemicals can accumulate in aquatic animals
HPAH
Tributyltin
Mercury
Fish tissue concentrations exceed concentrations in reference fish
0
0.1
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0 500 1000 1500 2000 2500
Cumulative Pe
rcen
tile by
Site
Total Homologs (ww)
whole body
Southwest
NASSCO
Reference
Spotted sand bass
Fisher interactions
Sediment re‐suspension with engine testing and docking
Polygon SW 29
Rank of SW 29
0
1000
2000
3000
4000
5000
6000
SW02 SW04 SW21 SW08 SW28 SW29 SW20 SW01 SW05 SW23 NA19
Total PCB
(µg/kg)
Incremental cleanups are important to preserving beneficial uses of the Bay