7 
chlorinated hydrocarbons in their bodies.”® Eggs of these pelicans 
frequently collapsed due to a deficiency of calcium carbonate which 
was highly correlated to the amounts of DDE in the birds. The birds 
with less DDE showed less shell thinning. Many other species of birds 
have since been shown to react in a similar manner to ingested DDE 
from marine fish. These birds include double-crested cormorants, 
American egrets, common murres, American kestrel, ashy petrels, and 
mallard ducks. In addition, there is circumstantial evidence to indicate 
that such species as peregrine falcon, osprey, and bald eagle are having 
reproductive failures due to ingested chlorinated hydrocarbons. 
Chlorinated hydrocarbon insecticides such as dieldrin and hepta- 
chlor epoxide have been detected in resident wildlife in Antarctica. 
Dieldrin has also been found in some sea birds. Another chlorinated 
hydrocarbon, endrin, is extremely poisonous to life forms requiring 
concentrations of only 2.6 ppb (parts per billion) in water to kill 
juvenile fish of some species. This compound has been found in fish 
from the Mississippi River and in brown pelicans from Florida and 
the Gulf of California. Since the early sixties, the brown pelican has 
disappeared from along the coast of Louisiana. Previously it had 
been the state bird of Louisiana. It is possible that endrin in the fish 
the pelicans ate caused their disappearance from the Gulf coast. 
Effects of chlorinated hydrocarbons on fish reproduction have also 
been studied. Concentrations of chlorinated hydrocarbons necessary 
to impair reproduction (0.2 to 2.0 ppm) were of the same order as 
those found in Lake Michigan eggs of coho salmon and in the kiyi, 
a species formerly abundant in Lake Michigan but which has become 
rare. Tables IJ and II hist DDT and PCB concentrations in plankton 
and fish from many areas of the world. There is no proof that these or 
other marine species are or will be harmed by these concentrations, but 
there are reasonable grounds for concern, especially if accumulation 
continues. One goal of the International Decade of Ocean Exploration 
(IDOE) is to establish a worldwide monitoring program to determine 
the distribution and biological effects of chlorinated hydrocarbon 
compounds and other pollutants. Every nation is encouraged to 
participate in this effort. The future of many populations of marine 
birds and fish is clearly related to the rates of accumulation of chlori- 
nated hydrocarbons in marine ecosystems. 
TABLE I1.—DDT AND PCB IN PLANKTON 
Totals (ug/kg wet weight) 
No. of 
Area samples DDT PCB 
ES AN ASSONG Galen. eu tew ee emma eM. LU nnLleny EMG AMAA RE kk Mina ae EMO ft 4 0.7 7-450 
ES OLENA CLANITI Cee eum tve asthe cues MAUD UU ALE ae I ai a UT 4 .2-2.6 19-638 
NonineastyA tlanticn seis a2 et Maea i EN Gae CR URE SIS Tee Ie rea hs 22 2-26 10-110 
IG IVE RS COLL Ti CE aE S NOG ys ee DET EEN Ee PEATE UL Ss Seed 15 6-130 40-230 
CALIF OTM iat SA eee UE SL Sa Le LTT iv LA SRC oe 15 - 2-206 . 7-30 
CO ef LT I RANE 8, CU BS SU a PASTA) MR aE EU SL AB 100-1300 
Aceland (phy toplanktom) sees ss a SO Ee INI OAS a ea [Ree eh SN eae 500 
_ Source: !DOE. Baseline studies of pollutants in the marine environment and research recommendations. IDOE Basee 
tine Conference, May 24-26, 1972. New York, IDOE Baseline Conference, p. 12. 
7 Risebrough, R. W., D. B. Menzel, D. J. Martin, and H. S. Olcott. DDT residues in Pacific sea birds: 
a persistent insecticide in marine food chains. Nature, v. 216, 1967: 589-591. 
8 Risebrough, R. W. Chlorinated hydrocarbons. In Impingement of Man on the Oceans (Hood, D. W., 
ed.). New York, Wiley-Interscience, 1971: 259-286. 
