Document jygNv7yDD40dXOkGqypjVxG95

BACK TO MAIN ACUTE ORAL TOXICITY TO TERRESTRIAL INVERTEBRATES (HONEY BEE) TEST SUBSTANCE Identity: Perfluorooctanesulfonate; may also be referred to as PFOS or FC-95. (1-Octanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8heptadecafluoro-, potassium salt, CAS # 2795-39-3) Remarks field: The 3M production lot number was 217. The test substance is a white powder. Sample was stored AT 16-20oC prior to testing. Purity determined to be 86.9% by LC/MS, 1H-HMR, 19F-NMR and elemental analyses techniques. METHOD Method: OECD Guideline 213, EPPO Guideline 170 Test type: Acute Oral GLP: Yes Year Completed: 2001 Species: Apis mellifera L. Analytical monitoring: None - nominal concentrations Test honey bee source: Obtained from colony number 32 belonging to the Central Science Laboratory (CSL), Sand Hutton, York, UK, National Bee Unit. Test honey bee age at study initiation: Young adult Test honey bee type: Worker honey bees, free of acarine, nosema and amoeba. Varroacide treatment: None within the 4 weeks prior to test initiation. Test conditions Humidity: 65% + 5% Temperature: 25 + 2oC Lighting: Conducted in darkness Stock and test solutions preparation: Test substance: Initial stock solution prepared in analytical grade acetone to a final concentration of 47.8 gg PFOS/pL (nominal concentration). Final test concentrations prepared from dilutions of this solution with 50% w/v sucrose. Resulting acetone concentration was 5%. Reference toxicant: Primary stock solution of dimethoate was prepared in deionized water containing 1 g/L Triton X-100 to a final concentration of 3.0 gg/gL. Secondary stock solutions were made BACK TO MAIN by diluting the primary stock solution in deionized water containing 1 g/L Triton X-100. Final test concentrations prepared from dilutions of these solutions with 50% w/v sucrose. Stability of the test chemical solution: A dispersion test was carried out on an 86 gg PFOS/pL acetone solution before the toxicity study was performed. The homogeneity of the mixture was assessed after 2 hours. The test item formed a clear solution on mixing; after 2 hours at room temperature, slight sediment was noted. For the toxicity test, all solutions were re-mixed prior to use. The contract laboratory considered the solutions of the test doses to be homogenous for the purpose of administration. Exposure vessels: Clean, well-ventilated, inverted petri dishes, measuring approximately 9 cm in diameter. Feeding: During the first four hours of the test, bees provided with 50% w/v aqueous sucrose solutions containi ng the appropriate PFOS dose. After 4-hours, dosed sucrose removed, and bees provided with 50% w/v aqueous sucrose solutions, continuously available through the end of the exposure period. Number of replicates: Three Number of bees per replicate: Ten Negative control: 50% w/v sucrose Solvent control: 50% w/v sucrose plus 5% acetone Reference substance: Dimethoate Reference substance control: Triton X-100 Number of concentrations: five plus a negative and a solvent control Dose administration: The bees were anaesthetized with carbon dioxide immediately before dosing and gently tipped out onto filter paper and counted into the petri dish cage (drones were discarded). Each group of 10 bees was offered 0.2 mL of a given test concentration or control solution. The dose was measured into a small, pre-weighed, glass feeder within the cage using a variable volume pipette. This volume of solution is equivalent to 20 pL per bee. Dose frequency: Once, for 4 hours of exposure Dose calculation: Feeders were weighed after removal from the cages to determine the dose consumed per bee. Element basis: Mortality RESULTS Nominal concentrations: Negative control (sucrose only), acetone + sucrose control, 0.205, 0.450, 0.991,2.17, 4.78 pg/bee Element value and 95% confidence interval : 24-hour LD50 = 0.72 (0.60 - 0.85) pg/bee 48-hour LD50 = 0.46 (0.32 - 0.55) pg/bee BACK TO MAIN 72-hour LD50 = 0.40 (0.33 - 0.48) jg/bee 72-hour NOEL = 0.21 |jg/bee All element values based on nominal concentrations Statistical Evaluation: Probit mortality plotted against the logarithm of dose using the contract laboratory Probit 1 package. A least-squares regression (Finney 1971) was fitted to these. The NOELs were estimated using Student's t-test (p<0.05) Biological observations: There was significant mortality at all doses above a mean intake of 0.21 jg/bee with a steep dose response between mean intakes of 0.45 and 2.2 jg/bee. Cumulative percent mortality:______________________ N om inal Test Conc., |jg /b e e 4-hours 24-hours 48-hours 72-hours Negative C ontrol Solvent Control 0.205 0.450 0.991 2.17 4.78 0 0 0 0 0 6.7 30 0 3.3 0 20 70 100 100 0 3.3 6.7 50 93 100 100 0 3.3 10 60 97 100 100 Sub-lethal Effects - Percent Knockdown (K) or Stumbling (S): N om inal Test Conc., jg /b e e 4-hours 24-hours 48-hours 72-hours Negative C ontrol 0 0 Solvent Control 0 0 0.205 00 0.450 0 3.3 (S) 0.991 00 2.17 00 4.78 10 (K) 0 Control response: satisfactory 0 0 0 3.3 (K) 0 0 0 0 0 0 3.3 (K) 0 0 0 Reference toxicant response: satisfactory - dimethoate 72-hour LD50 = 0.11 jg/bee BACK TO MAIN CONCLUSIONS The potassium perfluorooctanesulfonate 72-hour oral LD50 for the honey bee was determined to be 0.40 pg/bee with a 95% confidence interval of 0.33 - 0.48. The 72-hour no observed effect level was 0.21 pg/bee. The dose response was steep between a mean uptake of 0.45 and 2.2 pg/bee. Submitter: 3M Company, Environmental Laboratory, P.O. Box 33331, St. Paul, Minnesota, 55133 DATA QUALITY Reliability: Klimisch ranking 1 REFERENCES This study was conducted at Central Science Laboratory, Sand Hutton, York, UK, under contract by Wildlife International, Ltd, Easton, MD at the request of the 3M Company, Lab Request Number U2723, 2001. OTHER Last changed: 5/1/01