Optimization of in Situ Bioassays With Hyalella Azteca and Chironomus Tentans

Abstract

Abstract-Uncertainty is always associated with extrapolations of laboratory toxicity test responses to in situ conditions. Exposing toxicity test organisms in situ reduces uncertainty by removing sampling related artifacts and better simulating natural exposures. The amphipod Hyalella azteca and the midge Chironomus tentans, were enclosed in plastic containers with 149-or 74-mm mesh openings. These chambers were anchored to stream substrates allowing continual water exchange and contact with sediments. Hyallela azteca survival was greater than 80% after 4 weeks of exposure. In situ testing with H. azteca in cold water (Ͻ15ЊC) resulted in survival consistently below 60%, possibly due to limited acclimation periods. Handling stress during laboratory to field transport reduced C. tentans survival. High survival was not consistently achieved until a protective ground paper towel substrate was used. A smaller mesh size (74 mm) on the chambers reduced the occurrence of indigenous organisms inside the chambers, making C. tentans identification unmistakable. In situ testing with C. tentans using refined methods resulted in greater than 80% survival after 2 weeks of exposure. In situ exposures of these two benthic invertebrates can effectively evaluate short-to longterm conditions of water and sediment quality.

SERDP SEED Project (CS-1161) Final Report: Feasibility Study: Lab-on-a-chip and In Situ Bioassay Techniques for Rapid Resolution of Ion Signatures for Disturbances of Biological Significance in Streams

“…Often, the test animal(s) end(s) up either being indigenous to the waters being tested, or having a very wide distribution (Pontasch et al 1989). However, species typically used in laboratory bioassays have been used successfully in in situ bioassays as well (e.g., Chappie and Burton 1997;Periera et al 2000). But no one species can serve as a surrogate for the response of an entire biological community in a body of water, so attempts should be made to use more than one species, and if possible, consider more than one life stage (Cairns 1983;Cairns and Cherry 1993;Crane et al 1995;Lagadic and Caquet 1998;Parkhurst 1993).…”

Using artificial streams to assess the effects of metal-mining effluent on the life cycle of the freshwater midge (Chironomus tentans) in situ

“…These fluctuations may affect the degree or nature of effect that a contaminant may have on a study organism [1][2][3]. Certain conditions, such as temperature, photoperiod, and water quality, which are held at optimal levels in laboratory bioassays, tend to fluctuate in the field.…”

Comparison of Laboratory and in Situ Sediment Bioassays Using Corophium Volutator

“…These bioassays include those for phytoplankton [6], the freshwater amphipods Hyalella azteca [7,8] and Gammarus pulex [3,9], Daphnia magna [2], Ceriodaphnia dubia [10,11], the midge Chironomus tentans [8,12], the mayfly Caenis spec [7], the trichoptera Limnephilus lunatus [3], and the oligochaete Lumbriculus variegatus [12]. These bioassays include those for phytoplankton [6], the freshwater amphipods Hyalella azteca [7,8] and Gammarus pulex [3,9], Daphnia magna [2], Ceriodaphnia dubia [10,11], the midge Chironomus tentans [8,12], the mayfly Caenis spec [7], the trichoptera Limnephilus lunatus [3], and the oligochaete Lumbriculus variegatus [12].…”