ENVS 4000 Assignment II - SSDs and EEDs - 2024

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1 ASSIGNMENT II SPECIES SENSITIVITY and EXPOSURE DISTRIBUTIONS ENVS*4000 Toxicological Risk Characterization This assignment is worth 10% of your final grade and should be submitted to Courselink’s dropbox by 11:59 pm on Sunday, February 18 th (before midnight) . The total marks for this assignment are 52. You are advised to do any calculations etc., and even the entire answer, in rough before writing/typing it on the answer sheet. Marks will be deducted for poor grammar, syntax and spelling as well as for unclear or disorganized answers. Use only the space provided to respond unless otherwise indicated. Name: Cooper Stock Student Number: 1145398 SPECIES SENSITVITY DISTRIBUTIONS 1) You have been given a set of acute toxicity data for ammonia to various genera of aquatic organisms (Table 1). You have been asked to A) construct the species sensitivity distribution (SSD) for this toxicant and B) estimate the concentration at which 5% and C) 95% of organisms would be impacted by exposure to ammonia. For Part A , please attach a graph showing the SSD, with properly labeled axes, and the theoretical distribution with the best fit. Show how you decided which theoretical distribution to use. Graphs need to be produced in R. Provide a figure caption. (10 marks) B. The concentration at which 5% of aquatic organisms will be impacted by ammonia is 0.775mg/L. (2 mark) C. The concentration at which 95% of aquatic organisms will be impacted by ammonia is 14.104mg/L. (2 mark) Table 1: The acute 24hr LC 50 s for various aquatic genera to ammonia. Genus Acute LC 50 (mg/L) Hyalella 3.2 Ceriodaphnia 12.1 Ictalurus 0.7 Muscullium 1.4 Lepomis 2.9 Micropterus 5.9 Pimephales 2.5 Catostomus 8.8

2 Distribution AIC AICc Delta lnorm 43.82596 46.22596 0 gamma 43.83475 46.23475 0.009 invpareto 45.3445 47.7445 1.519 llogis 44.33832 46.73832 0.512 lgumbel 45.01756 47.41756 1.192 weibull 43.94728 46.34728 0.121 gompertz 44.13251 46.53251 0.307 Table 1.1: Results of goodness of fit measures for selecting best distribution model to create species sensitivity distribution. A kaike’s Information Criterion corrected for sample size ( AICc) is the metric being assessed for selecting the best distribution model, due to it being more accurate than the standard AIC for smaller samples. Log-normal (lnorm) was therefore selected due to it possessing the smallest AICc value and delta. Figure 1: Species sensitivity distribution for ammonia for different aquatic genera using data from Table 1. Log-normal distribution was used for normalizing data, which was decided with results from best-fit measures from Table 1.1. The log-concentration of ammonia is represented on the x-axis, and the percentage of species affected is represented on the y-axis. The shaded area represents the lower (left) and upper (right) confidence intervals of the sensitivity curve. This figure was created using the “ggplot2” library in R.

3 EXPOSURE AND EFFECT DISTRIBUTIONS 1) You have been given a data set of toxicity values for trichloroacetic acid (TCA) (Table 2), a disinfection by-product with herbicidal effects, to a suite of aquatic organism genera and TCA concentrations found in various Canadian Rivers (Table 3). You have been asked to A) calculate the species sensitivity distributions (SSDs) for this toxicant to primary producers and non-primary producers, B) calculate the exposure distributions for the two rivers, and C) estimate the risk of exceeding the 5 th centile for primary producers and non-primary organisms in the Saskatchewan and Red Rivers. For Part A , please attach a graph for primary producers and a graph for non-primary producers showing the SSDs, with properly labeled axes, and theoretical distribution with the best fit. Show how you decided which theoretical distribution to use. Graphs need to be produced in R. Provide a figure caption. (12 marks) Distribution AIC AICc Delta gamma 224.9663 226.2996 0 weibull 225.0093 226.3426 0.043 lnorm 225.483 226.8163 0.517 llogis 226.1694 227.5027 1.203 invpareto 226.7996 228.1329 1.833 lgumbel 227.9605 229.2938 2.994 Table 2.1: Results of goodness of fit measures for selecting best distribution model to create non-primary producer species sensitivity distribution. The gamma distribution was selected for redistributing the data due to it possessing the smallest AICc and delta values.

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4 Figure 2: Species sensitivity distribution for trichloroacetic acid (TCA) for different non-primary producer species using data from Table 2. Gamma distribution was used for normalizing data, which was decided with results from best-fit measures from Table 2.1. The log-concentration of TCA is represented on the x- axis, and the percentage of species affected is represented on the y-axis. The shaded area represents the lower (left) and upper (right) confidence intervals of the sensitivity curve. Distribution AIC AICc Delta gamma 40.88426 44.88426 0 lnorm 41.29087 45.29087 0.407 invpareto 41.46791 45.46791 0.584 llogis 41.8947 45.8947 1.01 lgumbel 42.10044 46.10044 1.216 weibull 40.99056 44.99056 0.106 Table 2.2: Results of goodness of fit measures for selecting best distribution model to create primary producer species sensitivity distribution. The gamma distribution was selected for redistributing the data due to it possessing the smallest AICc and delta values. Figure 3: Species sensitivity distribution for trichloroacetic acid (TCA) for different primary producer species using data from Table 2. Gamma distribution was used for normalizing data, which was decided with results from best-fit measures from Table 2.2. The log-concentration of TCA is represented on the x- axis, and the percentage of species affected is represented on the y-axis. The shaded area represents the lower (left) and upper (right) confidence intervals of the sensitivity curve.

5 For Part B , please attach a graph for each river, i.e., Saskatchewan, Red, and Grand showing the exposure distributions, with properly labeled axes, and theoretical distribution with the best fit. Show how you decided which theoretical distribution to use. Show how you decided which theoretical distribution to use. Graphs need to be produced in R. Provide a figure caption. (18 marks) River Distribution AIC AICc Delta Red (best) gompertz 116.3793 117.3793 0.000 Red (chosen) gamma 116.4897 117.4897 0.110 Saskatchewan lnorm 154.0996 155.0996 0.000 Grand invpareto 142.1832 143.1832 0.000 Table 2.3: Goodness of fit statistics for exposures of TCA in Canadian rivers, using data from Table 3. Only the best fit distribution is depicted for the rivers with all their associated measures of fit. Red River’s distribution was manually selected to be the second best fit as the Gompertz distribution did not maintain confidence intervals and was therefore not used for redistributing data. Figure 4: Environmental exposure distribution of trichloroacetic acid (TCA) in Red River created from samples in Table 3. Gamma distribution was used for fitting the data from Table 3 using R. The red line represents the gamma distribution curve, and the green lines represent the lower (left) and upper confidence intervals (right).

6 Figure 5: Environmental exposure distribution of trichloroacetic acid (TCA) in Saskatchewan River created from samples in Table 3. Confidence intervals are represented as the green curves, and the red curve represents the EED. Samples were redistributed using the theoretical log-normal distribution chosen in Table 2.3. The red line represents the gamma distribution curve, and the green lines represent the lower (left) and upper confidence intervals (right). Figure 6: Environmental exposure distribution of trichloroacetic acid (TCA) in Grand River created from samples in Table 3. Confidence intervals are represented as the green curves, and the red curve represents the EED. Samples were redistributed using the theoretical inverse-pareto distribution chosen in Table 2.3. u u

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7 The bottom four points are censored data, representing <0.5μg/L caused by the limit of quantification. The red line represents the gamma distribution curve, and the green lines represent the lower (left) and upper confidence intervals (right). Part C : I) The probability of TCA concentrations in the Red River exceeding the 5 th centile of toxicity for all primary producers is 0.70%. (2 mark) II) The probability of TCA concentrations in the Red River exceeding the 5 th centile of toxicity for non-primary producers is 0.00%. (2 mark) III) The probability of TCA concentrations in the Saskatchewan River exceeding the 5 th centile of toxicity for all primary producers is 75.88%. (2 mark) IV) The probability of TCA concentrations in the Saskatchewan River exceeding the 5 th centile of toxicity for non-primary producers is 0.00%. (2 mark) Table 2: The toxicity values for various aquatic genera to trichloroacetic acid (TCA). Species Latin Name Common Name Effect Level of Effect Exposure Duration Toxicity (mg/L) Pimephales promelas Fathead minnow Mortality LC 50 96 hrs 2200 Aedes aegypti Mosquito Mortality LC 50 96 hrs 5900 Salmonidae Rainbow Trout Mortality LC 50 96 hrs 1600 Nitocra spinipes Harpacticoid Mortality LC 50 96 hrs 4900 Dictospaerium pulchellum Green Algae Growth Inhibition EC 50 14d 16.3 Xenopus laevis African Clawed Frog Mortality LC 50 96 hrs 4400 Carassius sp. Goldfish Mortality LC 50 96 hrs 3000 Tinca tinca Tench Carp Mortality LC 50 96 hrs 3600 Chlorococcum sp. Green Algae Growth Inhibition EC 50 14d 1.1 Daphnia magna Water Flea Mortality LC 50 96 hrs 1000 Scenedesmus acutus Green Algae Growth Inhibition EC 50 14d 8.9 Chorella pyrenoidosa Green Algae Growth Inhibition EC 50 14d 0.1 Poecilia reticulata Guppy Mortality LC 50 48 hrs 8200 Chorella mucosa Green Algae Growth Inhibition EC 50 14d 0.6 Alburnus alburnus Bleak Carp Mortality LC 50 96 hrs 9900 Ankistrodesmus minutissimus Green Algae Growth Inhibition EC 50 14d 35.4 Cyprinus carpio Carp Mortality LC 50 96 hrs 2600 Leuciscus idus Orfe Carp Mortality LC 50 48 hrs 7200

8 Table 3: The measured environmental concentrations of trichloroacetic acid (TCA) for two Canadian rivers monitored during 2018 downstream of water treatment facilities. Sampling Date Saskatchewan River (μg/L) Red River (μg/L) Grand River (μg/L) 01/01/18 132 40 232 20/01/18 156 25 187 12/02/18 110 15 104 28/02/18 82 34 32 21/03/18 25 9 11 05/04/18 30 10 5 24/04/18 18 3 < 0.5 14/05/18 93 11 2 31/05/18 20 1 < 0.5 17/06/18 15 2 < 0.5 1/07/18 24 7 < 0.5 17/07/18 55 22 24 15/08/18 65 45 56 01/09/18 39 5 82 01/10/18 75 8 62

ENVS 4000 Assignment II - SSDs and EEDs - 2024

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