9 
natural pigmentation, developed a hyaline vesica, and finally dis- 
integrated.” ? 
Plankton blooms leading to toxic conditions in the water are well 
known from the phenomenon called the ‘‘red tide.”” Appearance of red 
tide is associated with overfertilization and is generally caused by 
upwelling of nutrient-rich water masses, but may also be caused by 
nutrient-rich effluent from land. These algae may directly poison and 
kill fish and even cause skin irritations to man when the algae are 
blown inshore with the foam. Filter feeders, which are not poisoned 
themselves by toxic algae, might accumulate the toxin in their flesh, 
and when eaten by man cause grave paralytic poisoning. In more diluet 
concentrations this fertilizer can be beneficial in stimulating reasonable 
levels of plant productivity, but it is suggested that the removal of 
these nutrients from sewage and their application on land would be of 
more economic benefit.'° Although not municipal sewage, anothér 
source of plant nutrients that should be included is runoff from agri- 
cultural areas. This source annually contributes significant quantities 
of nitrates and phosphates to the oceans either directly from coastal 
areas or by river systems. 
There are many additional effects of sewage disposal in the ocean 
such as pollution of fish and fishing gear by sludge material, destruc- 
tion of bottom fauna and flora by settled sludge, reduction of amenities 
by floating material washed on shore, and destruction of valuable 
recreation sites. These effects are, however, of a more or less local 
nature concentrated around outlets and dumping places. 
Bacteria and viruses are another problem of municipal wastes. 
Bacterial pollution is generally monitored by coliform bacteria counts. 
Coli in itself is not considered dangerous to human health, but the 
number of coli may be an indicator of the presence of other bacteria 
and viruses that cause such diseases as typhoid fever, hepatitis, and 
polio. The persistence of coliform and pathogenic bacteria in the sea 
is dependent on the amount of predation by protozoa or zooplankton, 
salinity, sunlight, tempearture, pressure, bacteriophage, and heat-label 
bacterial substances." Bacteria gradually disappear in the open ocean 
but can reach high concentrations in nearshore filter feeders. Re- 
searchers have studied the fate of poliovirus in Northern Quahaugs an 
found that several species of shellfish were capable of rapidly accumu- 
lating significant amounts of virus in their digestive tracts.” Outbreaks 
of infectious hepatitis associated with the consumption of raw oysters 
were reported in Sweden in 1956. Four outbreaks which involved 
approximately 900 cases of illness in the United States were also 
traced back to consumption of raw oysters, quahaugs, and hard 
clams.'? 
Parasites must also be considered in connection with disposal of 
municipal wastes in the sea. The possibility exists that marine ani- 
mals may be affected by human parasites released with the waste. 
§ Korringa, P. Biological Consequences of Marine Pollution With Special Reference to the North Sea Fishery 
Helgolander wiss. Meeresunters., Vv. 17, 1968: 126-140. 
10 Pentelow, F. T. K. Fish, Sewage and Sea Outfalls. Instit. Publ. Health Engrs. J., v. 60, 1961: 232 
11 Gunnerson, C. G. Sewage disposal in Santa Monica Bay, California. J. Sanit. Eng. Div. Amer. Soc. 
Civil Engrs., vy. 84, No. SA 1, Proc. paper 1534, 1958. 
2 Liu, O. C., H. R. Seraichekas, and B. L. Murphy. Fate of poliovirus in northern Quahaugs. Proc. Soc. 
Exp. Biol. Med., v. 121, 1966: 601-607. 
13 Mason, J. O. and W. R. McLean. Infectious hepatitus traced to the consumption of raw oysters.. 
Amer. Jour. Hyg. v. 75, 1962: 90-111. 
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