18 
Another effect of heated water on an ecosystem is the possible crea- 
tion of favorable environments for proliferation of pests into new 
areas. Such a case occurred recently in Oyster Creek, New Jersey 
where yacht basins were attacked by teredos or shipworms, a type of 
wood-boring clam. The problem resulted from a newly built nuclear 
power plant which raised the water temperature and increased the 
salinity of the Creek by diverting fresh water, enabling the pest to 
proliferate. 
The consequences of pouring billions of gallons of heated water into 
a body of water are not fully known, but evidence indicates that it is 
ecologically dangerous to assume the consequences are insignificant. 
Radioactivity —Since the accomplishment of a controlled nuclear 
reaction in 1942, man has begun to contaminate the oceans with 
artificial radioactivity. Artificial (man generated) radionuclides are 
produced by (1) fission of heavier elements such as plutonium or 
uranium, (2) fusion of light isotopes such as tritium and deuterium, 
and (3) neutron activation or bombardment of stable isotopes with 
neutrons. 
There are several sources of artificial radioactivity in the oceans 
but most of the radioisotopes presently found there resulted from at- 
mospheric testing of nuclear weapons. With decreased worldwide 
testing this source has become less significant. However, peaceful 
uses of nuclear energy are increasing. Many radionuclides are in- 
corporated in fallout from nuclear explosions. Those of greatest 
importance, because of their longer half lives and biologic activity, 
are iron (Fe), strontium (Sr®°), and cesium (Cs'87). Others such as 
iodine (I*!), barium (Ba™°), or lanthanum (La!°) may be biologically 
important for brief periods in the vicinity of the explosion. Runoff 
of radioactive fallout over land is not likely to reach the oceans in 
significant amounts. Fallout from nuclear excavations such as have 
been proposed to construct a sea level canal across Central America 
would, however, have a significant impact on radioactivity in nearby 
marine environments. Table XIIJ and Figure 1 illustrate the world- 
wide deposition of strontium (Sr®°°) fallout since 1957. 
TABLE XIII1—WORLDWIDE DEPOSITION OF SR% 
Average 
concentration 
in North 
Atlantic 
Annual Cumulative surface 
deposition ! deposition 1 waters? 
Year (MCi) (MCi) (upCi/1) 
Sources: 
1 Volchok, H. L. Worldwide Deposition of Sr8° Through 1969. In health and safety laboratory fallout program, quarterly 
summary report, July 1, 1970. USAEC HASL-227, 1970: 1-70-80. ; : 
2 Adapted from Bowen, V. T., V. E. Noshkin, H. L. Volchok, and T. T. Sugihara. Fallout Strontium-90 in Atlantic Ocean 
a ae In health and safety laboratory fallout program, quarterly summary report, July 1, 1968. USAEC HASL-197 
3 For first 6 months or 1967 only. 
