The dynamics of diquat in a model eco-system.

Muskelung (Esox-masquinongy chiensis) fry were used in a 96 hour toxicity study with diquat and simazine. Although the death of sufficient control fish invalidated the test as a whole, some interesting observations were made. At the end of 48 hours 4 out of 10 fish had died in the control tank and 8 had died in the simazine tank while all 10 diquat-treated fish appeared healthy. Two model eco-systems with components from Chautauqua Lake, N.Y. were constructed in 20 gallon glass aquaria to trace the movement of 14C labeled diquat. After activity had reached near background levels in the water from the test tank, fish, plants, sediments and snails were counted in a liquid scintillation counter to discover the fate of diquat within the system. The concentration of diquat was found to be highest in sediments, followed by fish tissue, snail parts, with plants having the lowest measured concentration.