Selenium uptake and transfer in an aquatic food chain and its effects on fathead minnow larvae

The transfer of Se (Na₂SeO₄) was followed through a laboratory food chain (wateralgae-rotifer-larval fish) and its effect on larval fathead minnows (Pimephales promelas). Selenium transfer between algae (Chlorella pyrenoidosa) and rotifers (Brachionus calyciflorus) was a function of time and food availability. Selenium concentrations in the rotifers ranged from 46 to 91g Se · g^–1 dry weight after 5 hr of feeding. Selenium concentrations (±SD) in larval fish reached 61.1±1.1 g Se · g^–1 dry weight for 9 day-old larvae and 51.7+1.6 g Se · g^–1 for 17 day-old larvae after 7 and 9 days of feeding with Se-contaminated rotifers, respectively. Final dry weights of larvae fed Se-contaminated rotifers were significantly lower than those of controls, although acute toxicity (mortality) was not demonstrated. The biological halflife of food-derived Se in the larvae was 28 days.Based on a thesis by William N. Bennett submitted in partial fulfillment for the degree of Master of Science in Zoology at the University of Wisconsin-Milwaukee.