APPENDIX M. RE-ANALYSIS OF ATRA ZINE TOXICITY DATA USED FOR CONSTRUCTING PATI (3 Pages)

NOTES FOR MARCH 28-30, 2012, These notes describe the corrections and changes to the toxicity data fo r constructing the PATI relationship that were made between the finali zation of Appendix E and the more recent Table 19 in the white paper.

(1) All regression analyses used for slopes and EC 50s in original toxic ity parameter database were redone with all three TRAP mo dels instead of just logistic m odel. For the logistic analysis, this provided the same results within converg ence variation with the following exceptions: (a) Hinman 1989 Hydrilla – original analys is used the sigmoidal threshold model (b) Zagorc-Koncan 1996 Scenedesmus – original analysis used th e sigmoidal threshold model (c) Hoberg 1993c Lemna – original analysis (a nd report) had final concs rather than average (d) Roberts 1990 Selenastrum – original analysis had an error in one SGR

(2) In addition to correcting the above mistakes in the original analysis for the final compilation, it was noted that the report had a few errors that needed to be corrected in redoing the analyses. (a) Fairchild et al. 1994 Na jas – report has concen tration 8.4 – should be 9.4 (b) Fairchild et al. 1994 Lemna – multiple errors in SGR in the report – corrected to original (c) Hinman 1989 Hydrilla – slope in report table differs from that in analysis in appendix (d) Forney and Davis 1981 – slope in report table di ffers from that in an alysis in appendix

(3) Slopes for all three models were log-transformed and compiled for determination of mean and standard deviat ion in Statistica. Original log slopes – m ean = -0.058, stdv = 0.180 New log slopes – mean = -0.071, stdv = 0.195 (Logistic Model) Range 0.54,0.85,1.33 – mean = -0.059, stdv = 0.191 (Threshold Model) Range 0.56,0.87,1.36 – mean = -0.163, stdv = 0.186 (Piecewise Model) Range 0.45,0.69,1.05

(4) Author-reported EC50s for SGR surrogates that were used unchanged in the original analysis were used for the compilation for all three models these included: Versteeg 1990 Selenastrum

Turbak et al. 1986 Selenastrum Hersh and Crumpton 1989 Chlamydomonas, Chlorella Stratton 1981, 1984 Anabaena sp, Chlorella, Scenedesmus(5) Kallqvist and Romstad 1994 reported an EC10 of 27 and an EC50 of 110 for the SGR and this was converted to a slope for each model as follows:

Logistic: ܵ ൌ ୪୬ ሺ ೛ భష೛ ሻ
ସሺ୪୭୥ ሺ ா஼௣ ሻ ି୪୭୥ ሺ ா஼ହ଴ ሻ ሻ ൌ 0.900

ܵ ൌ ଵି ඥ ଶ௣ Threshold: ୪୭୥ ሺ ா஼ହ଴ ሻ ି୪୭୥ ሺா஼௣ሻ ൌ 0.906

ܵ ൌ ௣ି଴.ହ ୪୭୥ ሺ ா஼௣ ሻ ି୪୭୥ ሺ ா஼ହ଴ ሻ Piecewise: ൌ 0.656

(6) For Schafer et al 1993, the EC50 of 51 co rresponded to an 16.0% re duction in the SGR if this EC50 was for biomass increase and a 19.6% reduction in the SGR if this EC50 was for AUC, given an SGRC=1.06/d. This was extrapolated to an EC 50 for the SGR using all three models and using the low, med, high steepne ss from analyses of just algae data: Algae log slopes – mean = -0.054, st dv = 0.147 (Logistic Model) Range 0.63,0.88,1.24 – mean = -0.041, stdv = 0.146 (Threshold Model) Range 0.65,0.91,1.27 – mean = -0.155, stdv = 0.146 (Piecewise Model) Range 0.50,0.70,0.98 Because lower/upper bounds were within a factor of 2, estimates for the middle slope were used. This resulted in EC50s (assuming biomass vs AUC) of 128.2 vs 150.8, 131.2 vs 153.0, and 138.5 vs 156.0 for the logistic, threshold, and piecewis e models, respectively. The mean of the biomass versus AUC were used.

(7) For Larsen et al. 1986, calculations outlined in the report were repeated for both models and with the updated algal steepness in point(6) , resulting in update SGR EC50s as follows:

Test Species 14 C EC 50 ( μ g/L) SGR EC 50 Logistic SGR EC 50 Threshold SGR EC 50 Piecewise Selenastrum capricornutum 43 81 83 90 Ankistrodesmus sp. 66 124 127 138 Chlamydomonas reinhardi 37 70 71 78

Scenedesmus obliquus 48 90 92 101

Chlorella vulgaris 308 580 592 645 Stigeoclonium tenue 175 330 336 367

Ulothrix subconstricta 88 166 169 184 Anabaena cylindrica 204 292 294 317

(8) Kirby and Sheehan 1994 reported similar 10-day Lemna EC50s of 56, 60, and 62 for frond number, weight increase, and chlorophyll. Based on the average SGRC for Lemna, the frond EC50 was equated to a ECp for SGR and then to an EC50 for SGR using the range of steepness for Lemna. Lemna log slopes – mean = 0.115, stdv = 0.069 (Logistic Model) Range 1.01,1.30,1.53 – mean = 0.124, stdv = 0.055 (Threshold Model) Range 1.17,1.33,1.51 – mean = 0.014, stdv = 0.043 (Piecewise Model) Range 0.93,1.03,1.14(9) Calculated mean and stdv for logEC50 for new compilation – overall for all tests Original log EC50s – mean = 2.123, stdv = 0.366 New log EC50s – mean = 2.127, stdv = 0.365 (Logistic Model) – mean = 2.133, stdv = 0.366 (Threshold Model) – mean = 2.145, stdv = 0.366 (Piecewise Model)