Acute and chronic toxicities of arsenic(III) to fathead minnows, flagfish, daphnids, and an amphipod

Abstract

Acute and chronic toxicities of arsenic (III) (As) to four species of freshwater organisms were determined. All tests were flow-through exposures except the daphnid (Daphnia magna) tests which were static concentration renewal exposures. Acute exposures of fathead minnows (Pimephales promelas), flagfish (Jordanella floridae), and an amphipod (Gammarus pseudolimnaeus) to As resulted in 96-hr LC₅₀ or EC₅₀ estimates of 14,100, 14,400, and 874 μg/L, respectively. Daphnids were exposed to As with and without food resulting in 96-hr EC₅₀ estimates of 4,340 and 1,500 μg/L, respectively. Chronic exposures of 28 to 31 days duration were made for fathead minnows, flagfish, and daphnids. The chronic limit ranges (highest tested exposure concentration having no adverse effect and the lowest tested exposure concentration having an adverse effect) based upon the most sensitive measured parameters of body length and wet weight were 2,130 to 4,300 μg/L for fathead minnows and 2,130 to 4,120 μg/L for flagfish. Daphnids had chronic limits of 633 to 1,320 μg/L based upon survival and the measured parameters of reproduction and body length. Calculation of an acute test/chronic test ratio for fathead minnows, flagfish, and daphnids (fed and unfed) resulted in a range of values from 1.64 to 4.80.