PT08 Chronic and Sublethal Sediment Toxicity
Exhibit Hall
8:00 AM - Tuesday
(PT133) An evaluation of reconstituted water for use in chronic water-only and sediment toxicity tests with Hyalella azteca.
Ivey, C1, Ingersoll, C1, Brunson, E1, 1 U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, USA
ABSTRACT- The objective of this study was to evaluate various recipes for preparing reconstituted water for use in chronic toxicity tests with the amphipod Hyalella azteca. Previous studies conducted at CERC have found that H. azteca survival and growth is poor when various types of reconstituted water have been used to conduct chronic (>14d) water-only or sediment toxicity tests. Borgmann (1996) reported success using the addition of sodium bromide in reconstituted water with H. azteca. Personnel at USEPA in Duluth, MN have found that the addition of a small amount of Instant Ocean salts (16 to 1000 mg/L) improved 10- to 28-d survival and growth of H. azteca in Lake Superior water. A series of experiments were conducted simultaneously to evaluate the response of H. azteca in various reconstituted waters in 42-d water-only exposures. Waters evaluated were: (1) CERC Well Water (hardness 280 mg/L and alkalinity 250 mg/L as CaCO3 and pH 7.80), (2) ASTM hard water (hardness 160-180 mg/L and alkalinity 110-120 mg/L as CaCO3 and pH 8.2), (3) Borgmann (1996) water (hardness 120-140 mg/L and alkalinity 60-80 mg/L as CaCO3 and pH 8.0), and (4) ASTM hard water supplemented with 1.2 mg/L NaBr. A dilution series of Instant Ocean salts added to ASTM hard water were also evaluated (500, 250, 125, 63, 31 mg/L added to ASTM hard water). After 42 days, only CERC well, Borgmann (1996), and 500 mg/L Instant Ocean water supported >90% survival of amphipods. Borgmann (1996) water samples produced the most young (172) compared to CERC well water (76) and 500 mg/L Instant Ocean water (0 young). The addition of sodium bromide to ASTM water resulted in survival of only 73% at day 42. Results of this study indicate that the Borgmann (1996) water can be used to support survival, growth, and reproduction of H. azteca in chronic toxicity tests.
Key words: water-only toxicity, hyalella azteca, reconstituted water, sediment toxicity