DDT, Chlordane, Toxaphene and PCB Residues in Newport Bay and Watershed: Assessment of Hazard to Wildlife and Human Health - Reviews of Environmental Contamination and Toxicology - page 59

datasets from these seven species are consistent with the strong trend evident in
the red shiner data set. The combined evidence from all fi sh species lends far more
weight to the conclusion that fi sh tissue DDT concentrations are declining in the
watershed than could be concluded from data from any single species considered
alone. As to the important point that some of these fi sh species may range outside
the Bay to feed, and thus concentrations of DDT in the tissues of these fi sh species
may refl ect DDT obtained outside of Newport Bay, Allen et al. ( 2004 ) concluded
that “monitoring studies are needed to determine if elevated DDT levels in the
popular sport fi shes noted above are due to contamination in the bay or to sources
outside the bay.” Also, in a follow-up study, Allen et al. ( 2008 ) found mean DDT
levels in striped mullet from Newport Bay to be 499 ppb. As in the 2004 study (Allen
et al. 2004 ), the authors caution that: “striped mullet (the species with the highest
DDT levels) can leave the Bay and move up and down the coast. Its very high levels
of DDT may be accumulated outside the Bay (perhaps in the Los Angeles/Long
Beach Harbor area,”
Allen et al. ( 2008 ) also reported whole-body DDT levels in seven species of
forage fi sh that are consumed by birds in Newport Bay. The species average DDT
level was 143 ppb. The mean level was skewed by one species, the deep body anchovy,
a nocturnal feeder that had an average whole-body DDT level of 495 ppb.
Like the red shiner, mussels are good bioindicators. Mussel tissue data from
three locations in the Newport Bay Watershed—San Diego Creek, Upper Newport
Bay, and Lower Newport Bay—were evaluated for trends in DDT concentrations
over time. Like red shiner data, mussel tissue data collected since 1982 show statis-
tically signifi cant declines in DDT concentrations (Fig. 5 ). An exponential regression
analysis of mussel data, including the entire period of record from 1982 to 1999,

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Fig. 5 DDT in mussels from Newport Bay and Watershed. Data from California Mussel Watch
Program ( 1980 -2000). The mussel watch program ended in 2000