48 THE ROLE OF ALGAE AND PLANKTON IN MEDICINE 



River below the Hanford Atomic Energy plant in Washington. He esti- 

 mated that about 570 tons of wet weight plankton passed the plant daily, 

 with a resulting planktonic radioactivity about 0.6 curies per day. Analyses 

 indicated that 5-30 per cent of the plankton's radioactivity came from 

 isotopes with half-lives near to or longer than P 32 , while the remainder 

 was of shorter half-life. Some radioactivity persisted beyond 600 days' 

 decay. Since algae can transmit their radioactive toxicity right up through 

 the nutritional pyramid to higher food animals, it is clear that more than 

 conventional disposal methods must be devised for atomic wastes. 



An indirect application of algal attributes relates to mosquito con- 

 trol. Matheson 249 noticed that mosquitoes did not breed in certain pools 

 where Chara fragilis thrived; he and Hinman then postulated that the large 

 amount of oxygen from the algae either interferes with the larval food 

 supply or gives the mosquitoes indigestion. However, Biswas, 250 over a 

 decade later, insisted that algal flora provide not only food for the 

 mosquito, but also shelter! 



b. Animal Intoxications 



The microalgal scums, odors, and tastes described in the last section 

 produce chiefly esthetic problems. Of far greater import are the many 

 harmful reactions reported to have occurred in both animals and 

 humans. 253-273 Freshwater phytoplankton has been implicated since 1878 

 in the intoxication and death of domesticated animals, as well as water- 

 fowl, shorebirds, and their mammalian or avian predators. 



In Table VII we present a chronological summation of 38 incidents of 

 animal intoxications by phytoplankton as culled from the literature. In 

 most cases attacks occurred after the animals had drunk from lakes or 

 ponds containing heavy algal growth, usually during hot weather. They 

 have variously been suspected of being due to botulism, anthrax, or worm 

 infestations; or to poisons such as lead, arsenic, copper, cyanide, or alkali; 

 or, as in South Africa, to gallsickness (carried by ticks), lamsiekte, and 

 poisoning by plants such as senecio, gousiekte, and gifblaar. Also con- 

 fused with algal poisoning has been the African geel dikkop of sheep, 

 produced by photosensitizing toxins. 



The reported symptomatology of algal intoxications has varied, but the 

 most striking clinically have been the involvements of the neuromuscular 

 and respiratory systems. As described by Francis, 253 in the Australian 

 outbreak due to Nodularia spumigeria, "the animals developed stupor and 

 unconsciousness, falling and remaining quiet, as if asleep unless touched, 



