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 122

Table 25 DDT and
metabolites in Atlantic
menhaden regurgitated by
brown pelicans in South
Carolina in 1973. Data from
Table 14 in Blus et al. 1977

Residues ( ʼ g/g fresh wet wt)

DDE TDE(DDD) DDT

0.04 0.04 0.04

0.06 0.04 0.05

0.07 0.02 0.03

0.06 0.03 0.03

0.05 0.03 0.02

0.08 0.03 0.02

0.15 0.07 0.06

GM a 0.067 0.035 0.033

CL b 0.045-0.099 0.024-0.050 0.022-0.049

Range 0.04-0.15 0.02-0.07 0.02-0.06

a GM = geometric mean
b CL = 95% confi dence limits

preventing the full recovery of the colony. Limited observations in 1976 suggested
that an inadequate food supply also contributed to low productivity.
In 1977, Blus et al. published a follow-up report on the brown pelican breeding
colonies in South Carolina. Shells of eggs collected from 1969 to 1973 averaged
14-17% thinner than shells of eggs collected prior to the DDT era. Crushed shells
were thinner than shells from eggs that hatched. Shells of freshly laid eggs were thinner
than shells of hatched eggs. Residues of DDE in eggs decreased from 5.45 ppm in
1969 to 2.09 ppm in 1973. Reproductive success of 1.66 per nest in 1973 was
considered excellent. Atlantic menhaden, a major food item of the brown pelican,
contained a residue of 0.135 ppm total DDT as shown in the author's Table 14 that is
reproduced in Table 25 below. The menhaden were recovered from regurgitated
stomach contents in 1973. The biomagnifi cation value for total DDT from fi sh to
egg was 18. The total DDT residue in menhaden in the late 1960s was 0.295 ppm.
“The migratory habits of the Atlantic menhaden (15, 17) and the brown pelican
confound the signifi cance of biomagnifi cation noted in this study.”
Thompson et al. ( 1977 ) reported on a 1970-1971 study of brown pelicans in
Florida. Regurgitated food items from 14 colony sites were analyzed and found to
contain an average of 0.074 ppm total DDT in 1970 and 0.047 ppm in 1971. Total DDT
in fi sh collected in 1964-1965 averaged 0.174 ppm. Total DDT in brown pelican eggs
collected in 1971 from three colony sites averaged 1.27 ppm.
King et al. ( 1978 ) reported on DDT residues and shell thinning in addled brown
pelican eggs collected in 1970 along the Texas coast. The average total DDT residue
was 3.23 ppm and was negatively correlated with an average 11% shell thinning.
King et al. ( 1977 ) reported 10% thinning in brown pelican eggs collected in Texas
from 1970 to 1974. DDE levels declined from 3.2 ppm in 1970 to 0.86 ppm in 1974.
Endrin toxicity accounted for mortality in adult pelicans and may have caused
reproductive failure. Effects of DDE on reproduction during this period could not be
assessed due to the small populations and confounding endrin toxicity.