SREL Reprint #0538




Effects of Naturally Occurring Aquatic Organic Fractions on Cadmium Toxicity to Simocephalus serrulatus (Daphnidae) and Gambusia Affinis (Poeciliidae)

J. P. Giesy, Jr., G. J. Leversee, and D. R. Williams



Cadmium toxicity to Simocephallus serrulatus and Gambusia affinis in soft well water, highly organic pond water and well water containing various sized organic fractions isolated from pond water was determined and compared to Cd binding capacity of each water type.  Pond organics were separated into three nominal molecular diameter fractions (>0.0183 pm; 0.0183 <> 0.0032 pm; 0.0032 <> 0.0009 pm) using ultrafiltration.  Cadmium binding capacity was determined using selective ion electrodes.  Pond water and organic fractions bound Cd, reducing the amount of free Cd2+ as determined by Cd selective ion electrode.  Whole pond water reduced Cd toxicity to S. serrulatus but had little effect on Cd toxicity to G. affinis.  The three larger molecular diameter organic fractions reduced Cd toxicity to S. serrulatus, while the smallest fraction slightly increased Cd toxicity.  Cadmium 96 h LC50 values cannot be predicted from Cd binding capacities determined by selective ion electrode.


SREL Reprint #0538

Giesy, J.P., Jr., G.J. Leversee, and D.R. Williams. 1977. Effects of naturally occurring aquatic organic fractions on cadmium toxicity to Simocephalus serrulatus (Daphnidae) and Gambusia affinis (Poeciliidae). Water Research 11:1013-1020.

To request a reprint