Document 1Qbx1vYgd8bzyjBDDo7rVJjka

BACK TO MAIN TOXICITY TO AQUATIC PLANTS (SELENASTRUM CAPRICORNUTUM) TEST SUBSTANCE_____________________________________ Identity: Perfluorooctanoic acid, ammonium salt; may also be referred to as PFOA ammonium salt, Ammonium perfluorooctanoate, PFO, FC-116, FC-126, FC-169, or FC-143. (Octanoic acid, pentadecafluoro-, ammonium salt, CAS # 3825-26-1) Remarks: The 3M production lot number was 427. The test sample is FC-143, referred to by the test laboratory as N2803-4. The T.R. Wilbury study number is 895-TH. The purity of the sample was not sufficiently characterized, although current information indicates it is a mixture of 96.5 - 100% test substance and 0 3.5% C6, C7, and C9 perfluoro analogue compounds. METHOD Method: U.S. EPA-TSCA Guideline 797.1050 Test: Acute static GLP: Yes Year completed: 1996. Species: Selenastrum capricornutum Source: Originally from The Culture Collection of Algae at the University of Texas at Austin, maintained in culture medium at T.R. Wilbury, Inc., Marblehead, MA. Element basis: Algal cell counts (cells/ml), and specific growth rates. Exposure period: 96-hours Statistical methods: Cell densities, growth rates and percent inhibition values used to estimate the EC10, EC50, and EC90values and 95% confidence limits were calculated using the computer software of C.E. Stephan. The no observed effect concentration (NOEC) was calculated using one-way analysis of variance (ANOVA). Analytical monitoring: pH and temperature Test Conditions: Algal nutrient medium: U.S. EPA-recommended sterile enriched medium, prepared by spiking deionized water with nutrient stocks. The pH of the synthetic algal medium at test initiation was 7.5. Stock and test solutions preparation: A 1,000 mg/L primary stock solution was prepared in sterile enriched media. Appropriate amounts of this stock solution were added directly to dilution water to formulate the test media. BACK TO MAIN Exposure vessels: 250 mL glass Erlenmeyer flasks containing 50 mL of test solution. Agitation: Shaken continuously at 100 rpm Number of replicates: 3 Initial algal cell loading: 1.0 X 104cells/mL Number of concentrations: Five plus a negative control Lighting: ~400 ft-c from continuous cool-white fluorescent lighting Water chemistry: pH range: (0 - 96 hours) 7.5 - 9.6 (control exposure) 5.4 - 7.4 (l,000 mg/L exposure) Test temperature range: (0 - 96 hours) 23.5 - 23.7C RESULTS Nominal concentrations: Bk control, 62, 130, 250, 500, 1,000 mg/L. Element value and 95% confidence interval: 72-hour EC10 (cell density) = 310 (110 - 440) mg/L 72-hour ErC10 (growth rate) = 470 (380 - 550) mg/L 72-hour EC50 (cell density) = 520 (250 - 1,000) mg/L 72-hour ErC50 (growth rate) = >1,000 mg/L (C.l. not calculable) 72-hour EC90 (cell density) = >1,000 mg/L (C.l. not calculable) 72-hour ErC90 (growth rate) = >1,000 mg/L (C.l. not calculable) 96-hour EC10 (cell density) = 97 (77 - 120) mg/L 96-hour ErC10 (growth rate) = 220 (160 - 280) mg/L 96-hour EC50 (cell density) = 310 (280 - 350) mg/L 96-hour ErC50 (growth rate) = >1,000 mg/L (C.l. not calculable) 96-hour EC90 (cell density) = 1,000 (830 - >1,000) mg/L 96-hour ErC90 (growth rate) = >1,000 mg/L (C.l. not calculable) 96-hour NOEC (cell density): 62 mg/L 96-hour NOEC (growth rate): 500 mg/L Element values based on nominal concentrations BACK TO MAIN Biological observations after 96-hours: Mean Measured C oncentration, m g/L Mean Num ber o f C ells per mL Percent Inhibition via D e n s ity Percent Inhibition via G row th Rate C o n tro l 62 130 250 500 1,000 1,407,000 1,445,000 1,129,000 7 5 3 ,0 0 0 4 4 3 ,0 0 0 181,000 -3 20 46 69 87 0 6 13 25 42 Control response: Satisfactory Observations: Algal cell counts in each test vessel were determined by means of direct microscope counts with a hemocytometer. After 96 hours of exposure, there were no signs of aggregation, flocculation or adherence of the algae to the flasks in the control or any test treatment group. In addition, there were no noticeable changes in cell size, color or morphology when compared to the control. Reversibility of Growth Inhibition: Effect of the test substance was determined to be algistatic based on the results of the post-definitive test exposure. CONCLUSIONS______________________________________________ The test sample 96-hour EC50 and 95% confidence interval for Selenastrum capricornutum was determined using two calculation methods. By cell density, it was 310 (280 - 350) mg/L, and by growth rate >1,000 mg/L. The 96-hour NOEC was determined to be 62 mg/L using cell density and 500 mg/L using growth rate. No signs of aggregation, flocculation, or adherence were noted in any of the test solutions. This test substance was determined to be algistatic. Submitter: 3M Company, Environmental Laboratory, P.O. Box 33331, St. Paul, Minnesota, 55133. BACK TO MAIN DATA QUALITY Reliability: Klimisch ranking = 2. The study lacks analytical measurement of test substance concentrations in the test solutions and the sample purity is not sufficiently characterized. REFERENCES____________________________________________ This study was conducted at T.R. Wilbury Laboratories, Inc., Marblehead, MA, at the request of the 3M Company, Lab Request number N2803-4. OTHER____________________________________________________ Last changed: 4/01/01