Assignment 1 Key


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ASSIGNMENT 1 BIOMAGNIFICATION, HABER’S RULE, HAZARD ASSESSMENT AND PROBIT ANALYSIS ENVR/BOTN/ZOOL/AGRI 2180 and 2190 Introductory Toxicology This assignment is worth 15% of your final grade and is due at the start of class on Tuesday, February 20 th , 2007. The total marks for this assignment are 50. It is advised to do any calculations etc., and even the entire answer, in rough before filling in the answer sheet. Marks will be deducted for poor grammar, syntax and spelling as well as answers that are unclear or disorganized. Use only the space provided to respond and attached require graphs to the answer sheet with a staple. The graphs must be done using graphing software, such as Excel, SigmaPlot or other available software. Name: __________________________________ Student Number: __________________________ HABER’S RULE 1) Using Haber’s Rule on the data set in Table 1, plot the relationship and report the equation between time and the concentration required to cause a specific effect as a linear function. (6 marks) Remember to log transform the values! 2) You estimate the concentration of carbamate required to kill 50% of the Daphnia magna after 48 hours of exposure to be _2.08 or 2.05 or 2.1 ug/L_ . (1 mark.) Table 1: Acute toxicity data for Daphnia magna exposed to the carbamate insecticide carbofuran. Time LC 50 (μg/L) 12 8.4 24 4.2 72 1.4 96 0.98 168 0.61 BIOMAGNIFICATION 11) You are concerned about possible biomagnification of a perfluorinated surfactant, in this case, PFOS (perfluorooctance sulfonate), in arctic ecosystems. PFOS was one of the key ingredients in Scotchgard, formerly produced by 3M. To see if there are any concerns, you have sampled various zooplankton, fish, birds, marine and terrestrial mammals for PFOS in their tissue (see Table 2). The next step is to examine the trends in the data and plot the relationship between concentration versus trophic level. Before you do this, you need to determine the trophic level of each organism and normalize the tissue 1
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concentration to lipid content. For full marks, fill in Table 1, graph the relationship between PFOS concentration in the organism and trophic level, and report the regression equation. The graph, properly labeled with the regression equation reported, is worth 10 marks . Remember to log transform the concentration values! Use the following equation to calculate trophic level: λ = 2 + ( δ 15 N organism - δ 15 N Calanus hyperboreus )/3.8 Table 2: PFOS concentrations in selected biota in the Canadian Arctic. (10 marks) Species δ 15 N Tissue Concentration (ng PFOS/g tissue) Lipid Content (% of tissue) Lipid Concentration (ng PFOS/g lipid) Tophic Level ( λ ) Euaugaptilus hyperboreus 7.4 3.9 1.5 260.0 2.9 Calanus hyperboreus 3.8 1.3 1.3 100.0 2.0 Phoca hispida 14.5 649.1 8.9 7293.3 4.8 Alle alle 10.6 1325.7 10.2 12997.1 3.8 Boreogadus saida 12.5 987.6 9.7 10181.4 4.3 Ursus maritimus 18.6
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This note was uploaded on 07/05/2008 for the course BOTN 2180 taught by Professor Farenhorst,goldsborough,hanson during the Fall '07 term at Manitoba.

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