AQUATIC TOXICOLOGY OF TRACE ELEMENTS 



231 



after 522, 1033, and 1775 hr of continuous aqueous leaching of the 

 original 52-kg sample of precipitator-collected fly ash. At 522 hr 

 tests were conducted on eggs of the leopard frog and Fowler's toad 

 with undiluted ash effluent. Frog eggs suffered rapid and complete 

 mortality, and a hatching frequency of 46% was observed for 

 Fowler's toad. Survival was 97 to 99% for control populations 

 treated with the same influent water source used to supply the fly- 

 ash leaching chamber (Table 6). Bioassays were initiated at 1033 hr 

 on eggs of the redear sunfish. Undiluted effluent produced complete 

 mortality, and 0.1 and 0.01 dilutions gave survival frequencies of 42 

 and 90%, which closely approached control survival. In tests with 

 goldfish eggs conducted at 1775 hr, survival averaged 57, 76, and 

 88% for undiluted effluent and 0.1 and 0.01 dilutions, respectively. 

 Control survival was 92%. 



Effluent metal concentrations observed for the amphibian 

 bioassays approximated mean values given for the second elution 

 interval (Table 5). Although ash toxicants produced a near-LCgo 

 response for toad eggs, the exposure period was limited to only 1.5 

 days. In addition, developmental stages of Fowler's toad are highly 

 resistant to trace metals, compared with other amphibian and piscine 

 species (Birge, 1976). Animal species used for the initial toxicological 



TABLE 6 

 EMBRYO-LARVAL BIOASSAYS ON FLY-ASH EFFLUENT 



