Reactants # mols delG0 form delG0 reacts Products # mols delG0 form delG0 prods delG0 rxn logKeq Rxn 1 Cl 2  131.3  262.6 Cl2( aq) 1 6.9 6.9 0 e 2 0 0 0  262.6 6.9 269.5  47.2 Rxn 2 Cl 1  131.3  131.3 ClO 1  36.8  36.8 H2O 1  237.18  237.18 H+ 2 0 0 e 2 0 0 Sum( rea):  368.48 Sum( pro):  36.8 331.7  58.1 Rxn 3 Cl 1  131.3  131.3 HClO 1  79.9  79.9 H2O 1  237.18  237.18 H+ 1 0 0 e 2 0 0 Sum( rea):  368.48 Sum( pro):  79.9 288.6  50.6 Rxn 4 Cl 1  131.3  131.3 ClO2  1 17.1 17.1 H2O 2  237.18  474.36 H+ 4 0 0 e 4 0 0 Sum( rea):  605.66 Sum( pro): 17.1 622.8  109.1 Rxn 5 Cl 1  131.3  131.3 ClO2( aq) 1 117.6 117.6 H2O 2  237.18  474.36 H+ 4 0 0 e 5 0 0 Sum( rea):  605.66 Sum( pro): 117.6 723.3  126.8 Rxn 6 Cl 1  131.3  131.3 ClO3  1  3.35  3.35 H2O 3  237.18  711.54 H+ 6 0 0 e 6 0 0 Sum( rea):  842.84 Sum( pro):  3.35 839.5  147.1 Rxn 7 Cl 1  131.3  131.3 ClO4 1  8.62  8.62 H2O 4  237.18  948.72 H+ 8 0 0 e 8 0 0 Sum( rea):  1080.02 Sum( pro):  8.62 1071.4  187.8 Rxn 8 Cl2( aq) 1 6.9 6.9 ClO 2  36.8  73.6 H2O 2  237.18  474.36 H+ 4 0 0 e 2 0 0 Sum( rea):  467.46 Sum( pro):  73.6 393.9  69.0 Rxn 9 Cl2( aq) 1 6.9 6.9 HClO 2  79.9  159.8 H2O 2  237.18  474.36 H+ 2 0 0 e 2 0 0 Sum( rea):  467.46 Sum( pro):  159.8 307.7  53.9 Rxn 10 Cl2( aq) 1 6.9 6.9 ClO2  2 17.1 34.2 H2O 4  237.18  948.72 H+ 8 0 0 e 6 0 0 Sum( rea):  941.82 Sum( pro): 34.2 976.0  171.1 Attachment C to Appendix B 2: Charts 1b through 1e Sodium Chlorate Appendices  54 Rxn 11 Cl2( aq) 1 6.9 6.9 ClO2( aq) 2 117.6 235.2 H2O 4  237.18  948.72 H + 8 0 0 e  8 0 0 Sum( rea):  941.82 Sum( pro): 235.2 1177.0  206.3 Rxn 12 Cl2( aq) 1 6.9 6.9 ClO3  2  3.35  6.7 H2O 6  237.18  1423.08 H + 12 0 0 e  10 0 0 Sum( rea):  1416.18 Sum( pro):  6.7 1409.5  247.0 Rxn 13 Cl2( aq) 1 6.9 6.9 ClO4  2  8.62  17.24 H2O 8  237.18  1897.44 H + 16 0 0 e  14 0 0 Sum( rea):  1890.54 Sum( pro):  17.24 1873.3  328.3 Rxn 14 ClO  1  36.8  36.8 HClO 1  79.9  79.9 H + 1 0 0 Sum( rea):  36.8 Sum( pro):  79.9  43.1 7.6 Rxn 15 ClO  1  36.8  36.8 ClO2  1 17.1 17.1 H2O 1  237.18  237.18 H + 2 0 0 e  2 0 0 Sum( rea):  273.98 Sum( pro): 17.1 291.1  51.0 Rxn 16 ClO  1  36.8  36.8 ClO2( aq) 1 117.6 117.6 H2O 1  237.18  237.18 H + 2 0 0 e  3 0 0 Sum( rea):  273.98 Sum( pro): 117.6 391.6  68.6 Rxn 17 ClO  1  36.8  36.8 ClO3  1  3.35  3.35 H2O 2  237.18  474.36 H + 4 0 0 e  4 0 0 Sum( rea):  511.16 Sum( pro):  3.35 507.8  89.0 Rxn 18 ClO  1  36.8  36.8 ClO4  1  8.62  8.62 H2O 3  237.18  711.54 H + 6 0 0 e  6 0 0  748.34  8.62 739.7  129.6 Rxn 19 HClO 1  79.9  79.9 ClO2  1 17.1 17.1 H2O 1  237.18  237.18 H + 3 0 0 e  2 0 0 Sum( rea):  317.08 Sum( pro): 17.1 334.2  58.6 Rxn 20 HClO 1  79.9  79.9 ClO2( aq) 1 117.6 117.6 H2O 1  237.18  237.18 H + 3 0 0 e  3 0 0 Sum( rea):  317.08 Sum( pro): 117.6 434.7  76.2 Sodium Chlorate Appendices  55 Rxn 21 HClO 1  79.9  79.9 ClO3  1  3.35  3.35 H2O 2  237.18  474.36 H + 5 0 0 e  4 0 0 Sum( rea):  554.26 Sum( pro):  3.35 550.9  96.6 Rxn 22 HClO 1  79.9  79.9 ClO4  1  8.62  8.62 H2O 3  237.18  711.54 H + 7 0 0 e  6 0 0 Sum( rea):  791.44 Sum( pro):  8.62 782.8  137.2 Rxn 23 ClO2  1 17.1 17.1ClO2( aq) 1 117.6 117.6 0 e  1 0 0 0 17.1 117.6 100.5  17.6 Rxn 24 ClO2  1 17.1 17.1ClO3  1  3.35  3.35 H2O 1  237.18  237.18 H + 2 0 0 e  2 0 0 Sum( rea):  220.08 Sum( pro):  3.35 216.7  38.0 Rxn 25 ClO2  1 17.1 17.1ClO4  1  8.62  8.62 H2O 2  237.18  474.36 H + 4 0 0 e  4 0 0 Sum( rea):  457.26 Sum( pro):  8.62 448.6  78.6 Rxn 26 ClO2( aq) 1 117.6 117.6 ClO3  1  3.35  3.35 H2O 1  237.18  237.18 H + 2 0 0 e  1 0 0 Sum( rea):  119.58 Sum( pro):  3.35 116.2  20.4 Rxn 27 ClO2( aq) 1 117.6 117.6 ClO4  1  8.62  8.62 H2O 2  237.18  474.36 H + 4 0 0 e  3 0 0 Sum( rea):  356.76 Sum( pro):  8.62 348.1  61.0 Rxn 28 ClO3  1  3.35  3.35 ClO4  1  8.62  8.62 H2O 1  237.18  237.18 H + 2 0 0 e  2 0 0 Sum( rea):  240.53 Sum( pro):  8.62 231.9  40.6 Rxn H2O 2  237.18  474.36 O2( g) 1 0 0 1W H + 4 0 0 e  4 0 0 Sum( rea):  474.36 Sum( pro): 0 474.4  83.1 Rxn H2O 2  237.18  474.36 H2( g) 1 0 0 2W e  2 0 OH  2  157.3  314.6 0 Sum( rea):  474.36 Sum( pro):  314.6 159.8  28.0 Sodium Chlorate Appendices  56 Attachment C to Appendix B 2: Charts 1b through 1e Sodium Chlorate Appendices  57 Chart 1b: Case 1 Cl predominance ( below bolded lines) considering only Cl, Cl2( aq), ClO, and HClO.

10 12 14 16 18 20 22 24 26 28 30 32 34 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH pE 2a 3b 2b 3c 1a 1b 3a 2) ClO / Cl  3) HClO/ Cl  1) Cl2( aq)/ Cl

Cl  predominance Sodium Chlorate Appendices  58 Chart 1c: Case 1 Cl2( aq) predominance considering only Cl, Cl2( aq), ClO, and HClO.

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH pE 1a 1b 8a 9a 9b 9c 8b 8) ClO / Cl2( aq) 9) HClO/ Cl2( aq) 1) Cl2( aq)/ Cl

Cl2( aq) predominance Sodium Chlorate Appendices  59 Chart 1d: Case 1 ClO predominance ( enclosed by bolded lines) considering only Cl, Cl2( aq), ClO, and HClO.

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH pE 2a 2b 14a 14b 8 2) ClO / Cl  14) HClO/ ClO

ClO  predominance 8) ClO / Cl2( aq) Sodium Chlorate Appendices  60 Chart 1c: Case 1 Cl2( aq) predominance considering only Cl, Cl2( aq), ClO, and HClO.

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH pE 1a 1b 8a 9a 9b 9c 8b 8) ClO / Cl2( aq) 9) HClO/ Cl2( aq) 1) Cl2( aq)/ Cl

Cl2( aq) predominance Chart 1e: Case 1 HClO predominance ( enclosed by bolded lines) considering only Cl, Cl2( aq), ClO, and HClO.

10 12 14 16 18 20 22 24 26 28 30 32 34 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH pE 3b 14a 3c 14b 9a 9b 3a 3) HClO/ Cl  14) HClO/ ClO

HClO predominance 9) HClO/ Cl2( aq) Sodium Chlorate Appendices  61 Attachment D to Appendix B 2. Charts 3b to 3i. Sodium Chlorate Appendices  62 Chart 3b: Case 2 Cl predominance ( below the bolded line) considering Cl, Cl2( aq), HClO, ClO,

ClO2 , ClO2( aq), ClO3 , and ClO4 .

10 12 14 16 18 20 22 24 26 28 30 2 3 4 5 6 7 8 9 10 11 12 pH pE 2 3 4 5 6 7 1 2) ClO / Cl

3) HClO/ Cl  4) ClO2 / Cl

5) ClO2( aq)/ Cl

6) ClO3 / Cl

7) ClO4 / Cl  1) Cl2( aq)/ Cl

Cl  predominance Sodium Chlorate Appendices  63 Chart 3c: Case 2 Cl2( aq) predominance ( none  no overlap between Cl2( aq) regions above and below bolded lines) considering Cl, Cl2( aq), ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

5 7 9 11 13 15 17 19 21 23 25 27 29 2 3 4 5 6 7 8 9 10 11 12 pH pE 1 8 9 10 11 12 13 1) Cl2( aq)/ Cl  8) ClO / Cl2( aq)

9) HClO/ Cl2( aq) 10) ClO2 / Cl2( aq)

11) ClO2( aq)/ Cl2( aq)

12) ClO3 / Cl2( aq) 13) ClO4

/ Cl Cl2( aq) predominance ? No  no overlap with region below bolded line 13 Cl2( aq) predominance ? No  no overlap with region above bolded line 1 Sodium Chlorate Appendices  64 Chart 3d: Case 2 ClO predominance ( none  no overlap between ClO regions bordered by bolded lines) considering Cl, Cl2( aq), ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 2 3 4 5 6 7 8 9 10 11 12 pH pE 2a 14a 15 16 17 18a 2b 14b 14c 18b 8 2) ClO / Cl  14) HClO/ ClO

15) ClO2 / ClO  16) ClO2( aq)/ Cl O

17) ClO3 / ClO  18) ClO4 / ClO  8) ClO / Cl2( aq) ClO  predominance ? No  no overlap with mirror region below ClO  predominance ? No  no overlap with mirror region above Sodium Chlorate Appendices  65 Chart 3e: Case 2 HClO predominance ( none  no overlap between HClO regions bordered by bolded lines) considering Cl, Cl2( aq) ClO, HClO, ClO2 , ClO3 , and ClO4 .

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 2 3 4 5 6 7 8 9 10 11 12 pH pE 3a 14a 19 20 21 22a 3b 22b 14b 14c 9 3) HClO/ Cl 14) HClO/ ClO

19) ClO 2 / HClO 20) ClO 2( aq)/ HClO 21) ClO 3 / HClO 22) ClO 4 / HClO HClO predominance ? No  no overlap w ith similar region below 9) HClO/ Cl 2( aq)

HClO predominance ? No  no overlap w ith similar region above Sodium Chlorate Appendices  66 Chart 3f: Case 2 ClO2  predominance ( none  no overlap between ClO2  regions above and below bolded lines) considering Cl, Cl2( aq), ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

5 7 9 11 13 15 17 19 21 23 25 2 3 4 5 6 7 8 9 10 11 12 pH pE 15 23 24 25 4 19 10 4) ClO2 / Cl  15) ClO2

23) ClO2( aq)/ ClO2

19) ClO2 / HClO 25) ClO4 / ClO2  24) ClO3 / ClO2

10) ClO2 / Cl2( aq) ClO2  predominance ? No  no overlap with region below bolded line 24 ClO2  predominance ? No  no overlap with region above bolded line 4 Sodium Chlorate Appendices  67 Chart 3g: Case 2 ClO2( aq) predominance ( none  no overlap between ClO2( aq) regions above and below bolded lines) considering Cl, Cl2( aq), ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

 5  3  1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 2 3 4 5 6 7 8 9 10 11 12 pH pE 5a 16 20 23a 26 27 5b 23b 11 5) ClO2( aq)/ Cl

16) ClO2( aq)/ ClO  20) ClO2( aq)/ HClO 23) ClO2( aq)/ ClO2

26) ClO3

/ ClO 27) ClO4 / ClO2( aq) 11) ClO2( aq)/ Cl2( aq) ClO2( aq) predominance ? No  no overlap with region below bolded line 26 ClO2( aq) predominance ? No  no overlap with region above bolded portions of lines 5 & 23 Sodium Chlorate Appendices  68 Chart 3h: Case 2 ClO3  predominance ( none  no overlap between ClO3  regions above and below bolded lines) considering Cl, Cl2( aq), ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

 10  8  6  4  2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 2 3 4 5 6 7 8 9 10 11 12 pH pE 6 17 21 24 26 28 12 17) ClO3 / ClO

21) ClO3 / HClO 24) ClO3 / ClO2  6) ClO3 / Cl

26) ClO3 / ClO2( aq) 28) ClO4 / ClO3

12) ClO3 / Cl2( aq) ClO3  predominance ? No  no overlap with region below bolded line 28 ClO3  predominance ? No  no overlap with region above bolded line 6 Sodium Chlorate Appendices  69 Chart 3i: Case 2 ClO4  predominance ( above the bolded line) considering Cl, Cl2( aq), ClO,

HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

0 2 4 6 8 10 12 14 16 18 20 22 24 2 3 4 5 6 7 8 9 10 11 12 pH pE 7 18 22 25 27 28 13 7) ClO4 / Cl

18) ClO4 / ClO

25) ClO4 / ClO2  22) ClO4 / HClO 28) ClO4 / ClO3

27) ClO4 / ClO2( aq)

13) ClO4

/ Cl ClO4  predominance Sodium Chlorate Appendices  70 Attachment E to Appendix B 2. Charts 4c to 4g Sodium Chlorate Appendices  71 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0  2  4  6  8  10 4 6 8 10 0 5E 13 1E 12 1.5E 12 2E 12 2.5E 12 3E 12 3.5E 12 ClO Activity Ratio pE pH Chart 4c: Case 2 ClO Activity ratio considering Cl, ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

3E 12 4E 12 3E 12 3E 12 2E 12 3E 12 2E 12 2E 12 1E 12 2E 12 5E 13 1E 12 0 5E 13 Sodium Chlorate Appendices  72 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0  2  4  6  8  10 4 8 0.0E+ 00 1.0E 09 2.0E 09 3.0E 09 4.0E 09 5.0E 09 6.0E 09 7.0E 09 8.0E 09 9.0E 09 1.0E 08 HClO Activity Ratio pE pH Chart 4d: Case 2 HClO Activity ratio considering Cl, ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 . Sodium Chlorate Appendices  73 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0  2  4  6  8  10 4 8 0.00E+ 00 5.00E 17 1.00E 16 1.50E 16 2.00E 16 2.50E 16 3.00E 16 3.50E 16 ClO2  Activity Fraction pE pH Chart 4e: Case 2 ClO2  Activity fraction considering Cl, ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

3E 16 4E 16 3E 16 3E 16 2E 16 3E 16 2E 16 2E 16 1E 16 2E 16 5E 17 1E 16 0 5E 17 Sodium Chlorate Appendices  74 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0  2  4  6  8  10 4 8 0.0E+ 00 2.0E 15 4.0E 15 6.0E 15 8.0E 15 1.0E 14 1.2E 14 1.4E 14 1.6E 14 1.8E 14 2.0E 14 ClO2( aq) Activity Fraction pE pH Chart 4f: Case 2 ClO2( aq) Activity fraction considering Cl, ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

1.8E 14 2E 14 1.6E 14 1.8E 14 1.4E 14 1.6E 14 1.2E 14 1.4E 14 1E 14 1.2E 14 8E 15 1E 14 6E 15 8E 15 4E 15 6E 15 2E 15 4E 15 0 2E 15 Sodium Chlorate Appendices  75 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0  2  4  6  8  10 4 9 0.0E+ 00 5.0E 08 1.0E 07 1.5E 07 2.0E 07 2.5E 07 3.0E 07 3.5E 07 ClO3  Activity Fraction pE pH Chart 4g: Case 2 ClO3  Activity fraction considering Cl, ClO, HClO, ClO2 , ClO2( aq), ClO3 , and ClO4 .

0.0000003 0.00000035 0.00000025 0.0000003 0.0000002 0.00000025 0.00000015 0.0000002 0.0000001 0.00000015 0.00000005 0.0000001 0 0.00000005 Sodium Chlorate Appendices  76 Appendix C. Areas in the United States That Grow Selected Commodities on Which Sodium Chlorate Is Used Sodium Chlorate Appendices  77 Sodium Chlorate Appendices  78 Sodium Chlorate Appendices  79 Sodium Chlorate Appendices  80 Sodium Chlorate Appendices  81 Sodium Chlorate Appendices  82 Sodium Chlorate Appendices  83 Sodium Chlorate Appendices  84 Sodium Chlorate Appendices  85 Appendix D. Percent of Irrigated Acres Estimated for Cotton 53 The maturity of the crop is measured in terms of the maturity of the bolls and depends on the time of the year when cotton was set. Boll maturity is determined by visual observation of bolls in the field intended for harvest Sodium Chlorate Appendices  86 Cotton Sodium chlorate is used on cotton as a harvest aid ( defoliant, desiccant, or both). Timing of use as a defoliant depends on: ( a) Maturity of the crop; ( b) Condition of the crop; ( c) Prevailing weather conditions and ( d) Harvest schedule. However, timing depends mainly on maturity of the bolls53 and harvest schedule. Too late defoliation can increase the likehood of rot bolls and fiber damage. Lower temperatures as the Fall season progresses ( i. e., below 60 ° F; < 16 ° C) may inhibit the activity of defoliant. In general, good conditions for defoliation are high temperature, high humidity, low wind velocity, and high to adequate soil moisture. Stressed cotton by drought or retarded growth from cold weather can result in unsatisfactory defoliation. Therefore, there is a temporal and spatial variability in the timing of application of sodium chlorate. Thus, this spatial and temporal variability reflects also on the environmental fate of chlorate ( refer to the " Environmental Fate" section).

Cotton constitutes the crop of most extensive use of sodium chlorate, at about 90% of the total use of this chemical on agricultural commodities. However, not all of the harvested cotton may use sodium chlorate as a harvest aid. Table D 1 summarizes the number of harvested acres ( in descending order of total harvested acreage) in the major cotton growing states. The Table also includes the percent of crops that is irrigated. Note that all Pima cotton is irrigated, but the percent of irrigated upland cotton varies with region. The lowest percent of irrigation is in some eastern and south eastern states ( FL, VA, SC, TN, AL).

Table D 1. Cotton Production ( Harvest Acres) and Percent of Irrigated Acreage ( Source; USDA, Census of Agriculture, 2002)

State Upland Cotton, Acres Harvested Upland Cotton, % Irrigated Pima Cotton Acres Harvested Pima Cotton % Irrigated Texas 4,638,240 40 18,789 100 Georgia 1,267,150 26 None None Mississippi 1,157,432 35 None None North Carolina 924,097 2.5 None None Arkansas 921,316 77 None None Tennessee 533,755 1.8 None None Alabama 523,123 6.2 None None California 495,943 100 198,710 100 Louisiana 474,784 32 None None State Upland Cotton, Acres Harvested Upland Cotton, % Irrigated Pima Cotton Acres Harvested Pima Cotton % Irrigated Sodium Chlorate Appendices  87 Missouri 395,880 52 None None Arizona 214,880 100 7,842 100 South Carolina 208,420 7 None None Oklahoma 172,228 39 None None Florida 101,766 8 None None Virginia Kansas New Mexico 92,809 55,953 45,994 0.9 45 100 None None NM 7,051 None None 100 Sodium Chlorate Appendices  88 Appendix E. Maximum Labeled Application Rates and Crops for all Agricultural End Use Products Sodium Chlorate Appendices  89 Table E 1. Maximum Labeled Application Rates and Crops for all Agricultural End Use Products Label Crop Application rate ( lbs a. i./ Acre) Application method Helena 2 lb. Sodium chlorate defoliantdesiccant Cotton 5 Aerial or ground Second application may be required for cotton Grain 6 Helena 3 lb. Sodium chlorate defoliantdesiccant Chili Peppers 7.5 Aerial or ground Corn, beans, flas, grain sorghum, guar beans, rice, safflowers, southern peas, soybeans, sunflower 6 Cotton 4.5 Helena 6 lb sodium chlorate defoliant desiccant Dry beans, guar beans, flax, corn, rice, safflower, soybeans, sunflower 6 Aerial or ground Chili peppers 7.5 Cotton, grain sorghum 4.5 Leafex 2 defoliantdesiccant Cotton 5.3 ( Arizona) 4.7 ( all other states) Allows no more than two applications ( reapplication interval not specified)

Leafex 3 defoliantdesiccant Cotton 5.25 ( Arizona) 4 ( all other states) Allows no more than two applications ( reapplication interval not specified)

Grain sorghum, corn, rice, soybean, sunflower 6 Maximum number of applications not specified Shed a leaf " L" Cotton 3.75 Ground or aerial Rice ( MS only) 4.5 Soybean ( MS only), 6 Riverside sodium chlorate Corn 6 Aerial Cotton 3.75 Ground or aerial Dry beans, grain sorghum, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Table E 1. Maximum Labeled Application Rates and Crops for all Agricultural End Use Products Label Crop Application rate ( lbs a. i./ Acre) Application method Sodium Chlorate Appendices  90 Rice 6 Aerial Sodium chlorate 6 Dry beans, grain sorghum, guar beans, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Corn, flax, rice 6 Aerial Cotton 4.5 Ground or aerial Chili peppers 7.5 Ground or aerial D Leaf M cotton defoliant Cotton 4 Ground or aerial Britz cotton defoliant concentrate Cotton 4.58 Ground or aerial First choice cotton defoliant concentrate Cotton 5.52 Ground or aerial Chili peppers 9.2 Ground or aerial Grain sorghum 4.97 Ground or aerial Drexel Defol Chili peppers 7.5 Ground or aerial Corn, rice 6 Aerial Cotton 4.5 Ground or aerial Dry beans, flas, grain sorghum, guar beans, potatoes, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Ornamental gourds 6 Georgia only Ground or aerial Drexel Defol 6 Chili peppers 7.5 Ground or aerial Corn, rice 6 Aerial Cotton 4.5 Ground or aerial Table E 1. Maximum Labeled Application Rates and Crops for all Agricultural End Use Products Label Crop Application rate ( lbs a. i./ Acre) Application method Sodium Chlorate Appendices  91 Dry beans, flax, cucurbits, grain sorghum, guar beans, potatoes, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Drexel Defol 6W Chili peppers 7.5 Ground or aerial Corn, rice 6 Aerial Cotton 4.5 Ground or aerial Dry beans, flax, cucurbits, grain sorghum, guar beans, potatoes, safflower, southern peas, soybeans, sunflower, fallow ground 6 Ground or aerial Drexel defol 5 Chili peppers 7.5 Ground or aerial Corn, rice 6 Aerial Cotton 4.5 Ground or aerial Dry beans, flax, cucurbits, grain sorghum, guar beans, potatoes, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Drexel defol 750 Chili peppers 7.5 Ground or aerial Corn, rice 6 Aerial Cotton 4.5 Ground or aerial Dry beans, flax, cucurbits, grain sorghum, guar beans, potatoes, safflower, southern peas, soybeans, sunflower 6 Ground or aerial Clean crop sodium chlorate Cotton 4.5 Ground or aerial Table E 1. Maximum Labeled Application Rates and Crops for all Agricultural End Use Products Label Crop Application rate ( lbs a. i./ Acre) Application method Sodium Chlorate Appendices  92 Grain sorghum, safflower, soybeans, sunflower, rice 6 Ground or aerial ( except rice  aerial only) California restriction on safflower, soybeans, sunflower MAPCO brand poly foliant Cotton 5.76 Ground or aerial Moore AG Brand Poly Foliant Dry beans, guar beans, cotton, flax, grain sorghum, corn, rice, safflower, soybean, sunflower, southern peas 7.5 Ground or aerial Chili peppers, potatoes 12.5 Ground or aerial Flax, corn, rice 7.5 Aerial Pick Mor Cotton 4.7 Ground or aerial Sodium Chlorate Appendices  93 Appendix F. Estimated Average Percent Crop Treated for Sodium Chlorate on Selected Crops Sodium Chlorate Appendices  94 Estimate of Average Percent Crop Treated ( PCT) for Sodlium Chlorate on Selected Crops Alan Halvorson, BEAD/ EAB, 10/ 26/ 04 Avg PCT Data Source Beans, Lima, Fresh < 1% Source ( 1): 1998 & 2000 Beans, Lima, Process 2% Source ( 1): 2000 Beans, Snap < 1% Source ( 1): 1998, 2000 & 2002, and source ( 3)

Beans/ Peas, Dry < 1% Source ( 3)

Corn, Field < 1% Source ( 2): 1998  2003, and source ( 3)

Corn, Sweet < 1% Source ( 1): 1998, 2000 & 2002, and source ( 3)

Cotton 5% SLUA with data for 1998  2002, and source ( 2): 2003 Flax < 1% Source ( 3)

Guar  No data available Peas, Green < 1% Source ( 1): 1998, 2000 & 2002, and source ( 3)

Peppers, Non Bell < 1% Source ( 1): 1998, 2000 & 2002, and source ( 3)

Potatoes < 1% SLUA with data for 1998  2002 and source ( 2): 2003 Rice < 1% SLUA with data 1998  2002 Safflower 2% Source ( 4)

Sorghum < 1% Source ( 2): 1998 & 2003, and source ( 3)

Soybeans < 1% Source ( 2): 1998 & 2003 Sunflower < 1% Source ( 2): 1999, and source ( 3)

Wheat < 1% Source ( 2): 1998, 2000 & 2002, and source ( 3)

Data Sources:

( 1) USDA/ NASS Agricultural Chemical Usage: Vegetables ( 2) USDA/ NASS Agricultural Chemical Usage: Field Crops ( 3) EPA proprietary usage data, 1998  2003 ( 4) CA DPR, California Use Reports, 2000  2002 Sodium Chlorate Appendices  95 Appendix G: Description of the Risk Quotient Method Sodium Chlorate Appendices  96 The Risk Quotient Method is the means used by EFED to integrate the results of exposure and ecotoxicity data. For this method, risk quotients ( RQs) are calculated by dividing exposure estimates by ecotoxicity values ( i. e., RQ = EXPOSURE/ TOXICITY), both acute and chronic. These RQs are then compared to OPP's levels of concern ( LOCs). These LOCs are criteria used by OPP to indicate potential risk to non target organisms and the need to consider regulatory action. EFED has defined LOCs for acute risk, potential restricted use classification, and for endangered species.

The criteria indicate that a pesticide used as directed has the potential to cause adverse effects on nontarget organisms. LOCs currently address the following risk presumption categories: ( 1) acute  there is a potential for acute risk; regulatory action may be warranted in addition to restricted use classification; ( 2) acute restricted use  the potential for acute risk is high, but this may be mitigated through restricted use classification ( 3) acute endangered species  the potential for acute risk to endangered species is high, regulatory action may be warranted, and ( 4) chronic risk  the potential for chronic risk is high, regulatory action may be warranted. Currently, EFED does not perform assessments for chronic risk to plants, acute or chronic risks to non target insects, or chronic risk from granular/ bait formulations to mammalian or avian species.

The ecotoxicity test values ( i. e., measurement endpoints) used in the acute and chronic risk quotients are derived from required studies. Examples of ecotoxicity values derived from shortterm laboratory studies that assess acute effects are: ( 1) LC 50 ( fish and birds), ( 2) LD 50 ( birds and mammals), ( 3) EC 50 ( aquatic plants and aquatic invertebrates), and ( 4) EC 25 ( terrestrial plants). Examples of toxicity test effect levels derived from the results of long term laboratory studies that assess chronic effects are: ( 1) LOAEL ( birds, fish, and aquatic invertebrates), and ( 2) NOAEL ( birds, fish and aquatic invertebrates). The NOAEL is generally used as the ecotoxicity test value in assessing chronic effects.

Risk presumptions, along with the corresponding RQs and LOCs are summarized in Table G 1. Sodium Chlorate Appendices  97 Table G 1: Risk Presumptions and LOCs Risk Presumption RQ LOC Birds1 Acute Risk EEC/ LC 50 or LD 50 / sqft or LD 50 / day 0.5 Acute Restricted Use EEC/ LC 50 or LD 50 / sqft or LD 50 / day ( or LD 50 < 50 mg/ kg) 0.2 Acute Endangered Species EEC/ LC 50 or LD 50 / sqft or LD 50 / day 0.1 Chronic Risk EEC/ NOAEC 1 Wild Mammals1 Acute Risk EEC/ LC 50 or LD 50 / sqft or LD 50 / day 0.5 Acute Restricted Use EEC/ LC 50 or LD 50 / sqft or LD 50 / day ( or LD 50 < 50 mg/ kg) 0.2 Acute Endangered Species EEC/ LC 50 or LD 50 / sqft or LD 50 / day 0.1 Chronic Risk EEC/ NOAEC 1 Aquatic Animals2 Acute Risk EEC/ LC 50 or EC 50 0.5 Acute Restricted Use EEC/ LC 50 or EC 50 0.1 Acute Endangered Species EEC/ LC 50 or EC 50 0.05 Chronic Risk EEC/ NOAEC 1 Terrestrial and Semi Aquatic Plants Acute Risk EEC/ EC 25 1 Acute Endangered Species EEC/ EC 05 or NOAEC 1 Aquatic Plants2 Acute Risk EEC/ EC 50 1 Acute Endangered Species EEC/ EC 05 or NOAEC 1 1 LD 50 / sqft = ( mg/ sqft) / ( LD 50 * wt. of animal) LD 50 / day = ( mg of toxicant consumed/ day) / ( LD 50 * wt. of animal)

2 EEC = ( ppm or ppb) in water Sodium Chlorate Appendices  98 Appendix H. Discussion of Waived Environmental Fate Data Sodium Chlorate Appendices  99 Hydrolysis ( 161 1) ( Abiotic Hydrolysis) The chemistry of chlorate in water is dominated by redox reactions that require the presence of reductants ( inorganic and/ or organic). Because the 161 1 Hydrolysis study is conducted in abiotic media and in types of buffer solutions that are not likely to act as reductants, this study was waived as it was concluded that the study was not going provide any useful or very limited information, unless known environmental reductants were included in the aqueous media. Moreover, the redox chemistry of chlorate in water is extensively documented in the chemical literature.

Photodegradation in water ( 161 2) ( Direct Photolysis) The 161 2 study is conducted in the absence of chemical photosensitizers. That is, this study is designed to address the role of direct photolysis in aqueous media. A necessary, but not sufficient, condition for direct photolysis in environmentally significant aqueous media is that the chemical must absorb energy ( photon) in the sunlight wavelength range. Chlorate does not absorb energy in this range. Therefore, the 161 2 study was waived because it does not the necessary condition for direct photolysis..

Photodegradation on soil ( 161 3) This study was waived because the combined soil sterilization and variability in nature and concentration of reductants in soil are not likely to provide data that can identify that photolysis on soil contributes to the degradation of chlorate.

Note: Photoreactions induced by transfer of energy from photosensitizers in natural water and soils may contribute to the transformation of chlorate in the environment ( that is, indirect photolysis contribution). Many chemical reductants present in natural environments may also behave as photoreductants.

Anaerobic/ aerobic aquatic metabolism ( 162 3/ 162 4) and Aerobic/ Anaerobic soil metabolism ( 162 1/ 2) These studies would not likely produce useful information due to sodium chlorate antimicrobial properties that destroy the microbial populations in soil and water sediment systems. If the microbial population is destroyed, the study cannot adequately address the role of microorganisms in the degradation of chlorate.

Mobility in soil ( 163 1) Sodium chlorate is fully ionized in water. The chlorate anion is not likely to adsorb onto soils or sediments. Therefore, high mobility was anticipated. Guideline studies would not provide additional information.

Bioaccumulation in fish ( 165 4) The estimated log n octanol water partition coefficient is  7 ( i. e., it is a highly hydrophilic chemical) Therefore, the n octanol water partition coefficient does not trigger the need for a 165 4 study. 54 There are no direct applications to water bodies for uses as an herbicide. However, sodium chlorate can be used to generate chlorine dioxide in situ, which is used as an antimicrobial agent in drinking water disinfection and in microorganism control in water cooling systems. The focus of the present ecological risk assessment is solely for the terrestrial field uses of sodium chlorate. Aquatic uses are regulated under the jurisdiction of the Antimicrobial Division and Office of Water.

Sodium Chlorate Appendices  100 Aquatic field dissipation ( 164 2)

There are no direct applications of sodium chlorate to water bodies ( aquatic field). Therefore, this study is not required54. Sodium Chlorate Appendices  101 Appendix I. Impact of sodium from sodium chlorate on soil quality ( soil dispersion). Sodium Chlorate Appendices  102 The analysis was designed to assess the sodium adsorption ratio ( SAR) in acid near neutral and alkaline soils. These conditions were selected because they represent two different soil chemical equilibrium conditions for Ca and Mg, major competing cations on soil adsorption sites. Under the acid near neutral soil conditions, the Ca and Mg activities in soil solution are likely controlled simple cation exchange. These activities are described in chemical equilibrium terms as soil Ca and soil Mg. Under alkaline conditions, the Ca and Mg activities in soil solution are expected to be controlled by calcite ( CaCO 3 ) and dolomite ( MgCO 3 ) ( Lindsay, 1978). The sodium activity in soil solution ( under ideal conditions) was assumed to be controlled by the sodium chlorate application rate.

Predicted Na Concentration in soil solution Assumption:

A soil bulk density of 1.3 g/ cc, 20% field capacity the Na concentration in soil solution = 6.74 mg/ L= 2.933E 4 moles/ L= 0.29 moles/ m3 Predicted Ca Concentration in Soil Solution:

Acidic and Near Neutral Soil= Soil Ca Ca ( log K= 2.5)= Ca activity= 0.003 moles/ L= 3 moles/ m3 Alkaline Soil ( Assuming CaCO 3 equilibria)= CaCO 3 + 2H+ Ca 2+ + C0 2 ( g) + H 2 0 ( Log K= 9.74) ( log Ca 2+ = 9.74  2pH  log CO 2 ( g)) At CO 2 ( g) = 0.0003 atm and pH= 8.5 = Ca activity= 0.00018 moles/ liters= 0.18197 moles/ m3 At CO 2 ( g)= 0.003 atm and pH= 8.5= Ca activity= 0.000018 moles/ liter= 0.018197 moles/ m3 Predicted Mg Concentration in Soil Solution Acidic and Neutral Soil= Soil Mg Mg ( log K= 3.00)= Mg activity= 0.001 moles/ liter= 1 mole/ m3 Alkaline Conditions ( Assume equilibrium with calcite and dolomite) MgCa( CO 3 ) + 2H+ Mg 2+ + CO 2 ( g) + H 2 O + CaCO 3 ( Log K= 8.72) ( log Mg 2+= 8.72 logC0 2 ( g) 2pH)

At CO 2 ( g)= 0.0003 atm and pH 8.5 = 1.7 x 10 5 mole/ L= 0.01737 moles/ m3 At CO 2 ( g)= 0.003 atm and pH 8.5 = 1.7X 10 6 moles/ L= 0.001737 moles/ m3 Predicted Na concentration in Soil Solution Sodium Chlorate Appendices  103 Using the SAR equation= Na/( Ca+ Mg)^ 1/ 2 ( Sposito, 1989)

Acid Near Neutral Soil Conditions SAR ( acid/ neutral soils)= 0.29/( 3+ 1)^ 1/ 2= 0.145 Alkaline Soils ( pH 8.5) and CO 2 ( g)= 0.0003 SAR ( alkaline, pC02= 3.52)= 0.29/( 0.18197+ 0.01737)^ 1/ 2= 0.29/ 0.44= 0.6590 Alkaline Soils ( pH 8.5) and CO 2 ( g)= 0.003 SAR ( alkaline, pCO2= 2.52)= 0.29/ 0.018197 + 0.001737)^ 1/ 2= 0.29/ 0.14= 2.07 Sodium Chlorate Appendices  104 Appendix J. Discussion on Chlorate Redox Chemistry as it Relates to Exposure to Aquatic Organisms in the Environment 55 See " Water Chlorination: Chemistry, Environmental Impact and Health Effects", Volume 5. Edited by Jolley, R. L., et al. Lewis Publishers, 1985.

56 See http:// www. epa. gov/ oppefed1/ models/ water/ index. htm 57 " Standard Potentials in Aqueous Solutions", Edited by A. J. Bard, R. Parsons, and J. Jordan for the International Union of Pure and Applied Chemistry, Physical and Analytical Chemistry Divisions, Commissions on Electrochemistry and Electroanalytical Chemistry. Published by Marcel Dekker, New York, 1985.

Sodium Chlorate Appendices  105 Although there are some models55 available that are used in water chlorination, they are not suitable for uses that have a direct application to a terrestrial environment ( i. e., environmental conditions for chlorination in water treatment plants are markedly different than those found in terrestrial environments).

Because the chlorate chemistry is highly dependent on pH pE ( redox) conditions in the environment, these factors need to be considered in modeling the environmental fate and transport of chlorate. One problem is that environmental fate and transport models for pesticides ( GENEEC, SCI GROW, FIRST, PRZM) do not have the capability to quantitatively assess the impact of environmental redox potentials ( pH pE) on chemical speciation. Although the EXAMS component of PRZM EXAMS has the capability to use redox potential as an input parameter with specific chemical species, it also needs kinetics data ( which is difficult to obtain for redox systems such as the chlorine) 56 . Moreover, even if the kinetics data were available, the nature and predominance ( relative concentrations) of reduction products cannot be obtained using EXAMS.

Further refinement of the exposure assessment was conducted to investigate the impact of redox conditions on the distribution of chemical speciation of chlorine including: ( 1)) Chlorate, ClO 3 ; Cl( V); ( 2) Chlorite, ClO 2 ; Cl ( III); Hypochlorite, ClO ; Cl ( I); and Chloride, ClO; Cl ( I).

A chemical equilibrium modeling approach was used as a first approximation on the distribution of chemical species of chlorine as function redox potential. This approach, however, does not consider reaction kinetics. Reaction kinetics have been shown to be an important consideration in determining the stability of chlorate ( ClO 3 ) in soil and aquatic environments ( see reference). As discussed in 3.1.1, reaction kinetics of the chlorine system is extremely complex and most of data comes from study conditions that are not relevant to conditions found in the environment. However, thermodynamic data is readily available and was obtained from peer reviewed data included in publications widely used as reference ( see Appendix A) 57 A mole fraction diagram for chlorate and redox species for the reactions was constructed to show the relative predominance of chlorine species as function of redox potential ( Figure 1). This exercise demonstrated that chlorate ( ClO 3 ) and chlorite ( Cl0 2 ) under equilibrium conditions are not expected to be predominant Cl species under normal environmental redox potentials ( pe+ pH< 17). Hypochlorite was the predominant Cl species pe+ pH > ~ 17, which is outside the environmentally significant pe + pH range. As expected, the chloride ion ( Cl) was the Sodium Chlorate Appendices  106 pe + pH 2 4 6 8 10 12 14 16 18 20 Mole Fraction 0 20 40 60 80 100 CL02

CL0

Cl NO3   N02

Fe + 3  Fe + 2 SO4+ 2 vs S 2 predominant Cl species under normal environmental redox potentials ( pe+ pH < 17) These data suggest that chlorate and chlorite are not expected to be stable under normal environmental redox conditions in surface water. This assessment, however, assumes the kinetics of reactions do not control the rates of reduction and oxidation of the various chloride species. As previously discussed, the nature and concentration of redox species in natural water should also be taken into account. However, given the extensive spatial and temporal variability of redox species in natural water, a quantitative assessment cannot be performed.

Both the mole fraction and the activity fraction diagrams ( Appendix B 2) showed that, at thermodynamic equilibrium, chloride is the predominant chlorine chemical species under environmental conditions. The fraction diagram is illustrated in Figure J 1 below. Sodium Chlorate Appendices  107 Appendix K. Terrestrial EECs for the Maximum Labeled Application Rates for all of Sodium Chlorate's Current End Use Products Sodium Chlorate Appendices  108 Table K. Calculated EECs ( mg ai/ kg food item) for Terrestrial Animal Risk Assessment ( Non agricultural Uses)

Use Application rate ( lbs a. i./ Acre) Predicted 90th Percentile Residue Levels ( ppm) Predicted Mean Residue Levels ( ppm)

short grass tall grass broadleaf forage,

small insects fruit, pods, seeds,

small insects short grass tall grass broadleaf forage,

small insects fruit, pods, seeds,

small insects Industrial sites such as driveways, paths,

brick walks, cobble gutters, tennis courts 52 12500 5700 7000 780 4400 1900 2300 360 Driveways, parking lots, walks, around fences, curbs, similar areas. Not for use on lawns. 140 33600 15400 18900 2100 11900 5040 6300 980 Fence rows, rights of ways and similar areas; Around buildings, storage areas, fences,

recreational areas, guard rails, highway medians, industrial sites;

Around buildings, storage areas, fences,

pumps, machinery, fuel tanks, recreational areas, roadways, guard rails, airports, rights of ways. 160 38400 17600 21600 2400 13600 5760 7200 1120 Driveways, walks, patios, tennis courts,

curbs, garages, etc. 220 52800 24200 29700 3300 18700 7920 9900 1540 Table K. Calculated EECs ( mg ai/ kg food item) for Terrestrial Animal Risk Assessment ( Non agricultural Uses)

Sodium Chlorate Appendices  109 Industrial sites, rights of way, lumberyards,

petroleum tank farms, around farm buildings, along fence lines, and similar areas; Bleachers, fence lines, fire hydrants, helo pads, parking lots, runways, vacant lots. 240 57600 26400 32400 3600 20400 8640 10800 1680 Brick walks, patios, parking areas, along fences, curbs, gutters, around building,

graveled pathways, driveways, under asphalt paving 330 79200 36300 44550 4950 28050 11880 14850 2310 Bleachers, bridge abutments, buildings,

guard rails, helo pads, under asphalt,

concrete, gravel, driveways, sidewalks,

wood decks. 390 93600 42900 52650 5850 33150 14040 17550 2730 Parking lots, under asphalt paving, fence lines, building perimeters, ditch banks,

picnic areas, vacant lots, wood decks,

bleachers, cemeteries, fuel tanks, runways,

helo pads, etc.;

Bleachers, fence lines, fire hydrants, guard rails, parking lots, under driveways,

sidewalks, asphalt 520 125000 57000 70000 7800 44000 19000 23000 3600 Pre paving 650 157000 72000 88000 9800 56000 24000 29000 4600 Sodium Chlorate Appendices  110 Appendix L. Summary of Publically Available Data in EPA's ECOTOX Database Sodium Chlorate Appendices  111 Fish Common Name Endpoint Test Duration Duration Units Ref # LC50 ( ug/ L)

Brown trout LC50 48 h 448 LC50: 7,300 Cherry salmon, yamame trout LC50* 96 h 6034 LC50: 1,100,000 Cherry salmon, yamame trout LC50* 48 h 6034 LC50: 3,300,000 Cherry salmon, yamame trout LC50* 24 h 6034 LC50: 4,000,000 Cherry salmon, yamame trout NR ZERO 4 d 8138 NR Cherry salmon, yamame trout NR 2 d 8138 NR Cherry salmon, yamame trout NR 1 d 8138 NR Fathead minnow LC50 96 h 6051 LC50: 13,500,000 Fathead minnow LC50 96 h 6051 LC50: 13,600,000 Fathead minnow LC50 96 h 6051 LC50: 13,800,000 Goldfish NR 4 d 916 Endpoint Not Reported: 1,000,000 Harlequinfish, red rasbora LC50* 24 h 542 LC50: 8,600,000 Hasu fish LC50 96 h 12402 LC50: 2,340,000 Japanese barbel LC50* 10 d 6034 LC50: 2,000,000 Japanese barbel LC50* 96 h 6034 LC50: 3,300,000 Japanese barbel LC50* 48 h 6034 LC50: 3,800,000 Japanese barbel LC50* 48 h 6034 LC50: 3,800,000 Japanese barbel LC50* 96 h 6034 LC50: 3,800,000 Japanese barbel LC50* 24 h 6034 LC50: 4,000,000 Japanese barbel LC50* 24 h 6034 LC50: 4,200,000 Japanese barbel LC50* 12 h 6034 LC50: 4,700,000 Japanese barbel LC50* 6 h 6034 LC50: 4,900,000 Minnow LC50 96 h 12402 LC50: 2,340,000 Rainbow trout, donaldson trout LC50 48 h 344 LC50: < 1,100,000 Rainbow trout, donaldson trout NR NR wk 8139 Endpoint Not reported: No effects at 60,000 Hasu fish LC50 96 h 12402 LC50: 2,340,000 Sodium Chlorate Appendices  112 Fungi Scientific Name Endpoint Test Duration Ref # Concentration ( mM)

Penicillium verrucosum NOEC 48 hr 19279 >= 7.48 Trichoderma hamatum NOEC 48 hr 19279 >= 7.48 Aquatic Invertebrates, Laboratory Studies Scientific Name Common Name Test Duration Duration Units Ref # Concentration ( ug/ L, except where noted)

Asellus hilgendorfi Aquatic sowbug 96 h 6034 LC50: 2,100,000 Asellus hilgendorfi Aquatic sowbug 96 h 6034 LC50: 2,800,000 Asellus hilgendorfi Aquatic sowbug 48 h 6034 LC50: 3,100,000 Asellus hilgendorfi Aquatic sowbug 48 h 6034 LC50: 3,400,000 Asellus hilgendorfi Aquatic sowbug 24 h 6034 LC50: 4,100,000 Haliplus sp. Beetle 10 d 6696 NOEC: 105,500 Stenopsyche griseipennis Caddisfly 96 h 6034 LC50: 2,700,000 Stenopsyche griseipennis Caddisfly 24 h 6034 LC50: 3,100,000 Stenopsyche griseipennis Caddisfly 48 h 6034 LC50: 3,100,000 Cloeon dipterum Mayfly 24 h 6954 LD50: > 40,000 Cloeon dipterum Mayfly 3 h 6954 LD50: > 40,000 Cloeon dipterum Mayfly 48 h 6954 LD50: > 40,000 Cloeon dipterum Mayfly 6 h 6954 LD50: > 40,000 Baetis tricaudatus Mayfly 10 d 6696 NOEC: 104,000 Tricorythodes minutus Mayfly 10 d 6696 NOEC: 109,000 Polycelis nigra Planarian 48 h 10013 LT50: 0.15 ( M)

Rutilus rutilus Roach 96 h 12402 LC50: 2,340,000 Petromyzon marinus Sea lamprey 24 h 638 Endpoint Not Reported: 5,000 Isoperla longiseta Stonefly 10 d 6696 NOEC: 52,000 Isoperla transmarina Stonefly 10 d 6696 NOEC: 104,000 Daphnia magna Water flea 48 h 6696 LC50: 3,162,000 Sodium Chlorate Appendices  113 Daphnia magna Water flea 48 h 2130 Lethal concentration: 4,240,000 Daphnia magna Water flea 48 h 607 NOEC: 1,000,000 Dasycorixa hybrida 10 d 6696 NOEC 107,000 Table Notes. Aquatic Invertebrates, Field Studies Scientific Name Common Name Effect Trend Test Duration Duration Units Ref # Exposure Concentration ( ug/ L) Application Rate ( kg/ ha) Application Frequency Application Date Not Specified POP CHG NR wk 8139 <= 60,000 NR NR NR Not Specified POP DEC 7 h 8139 20,000  60,000 NR NR NR Not Specified POP CHG NR d 8138 0  57,000 200 1 X 10/ 13/ 69 Not Specified POP CHG NR d 8138 0  57,000 200 1 X 10/ 13/ 69 Not Specified POP CHG 4 d 8138 0  57,000 200 1 X 10/ 13/ 69 Ephemera japonica Mayfly MOR DEC 4 d 8138 800  57,000 200 1 X 10/ 13/ 69 Gammarus sp. Scud, Amphipod MOR DEC 4 d 8138 800  57,000 200 1 X 10/ 13/ 69 Note: Significance of Effects were not indicated Aquatic Plants Scientific Name Common Name Test Duration Ref # Concentration Units Nostoc calcicola Blue green algae 14 days 19279 NOEC: 3.74 mM Nostoc calcicola Blue green algae 14 days 19279 NOEC: 3.74 mM Ectocarpus variabilis Brown algae 14 days 19279 NOEC: < 0.005 mM Ectocarpus variabilis Brown algae 14 days 19279 LOEC: 0.005 mM Ectocarpus variabilis Brown algae 14 days 19279 EC50: 0.012 mM Ectocarpus variabilis Brown algae 14 days 19279 LOEC: 0.04 mM Ectocarpus variabilis Brown algae 14 days 19279 NOEC: 0.04 mM Ectocarpus variabilis Brown algae 14 days 19279 EC50: 0.14 mM Phaeodactylum Diatom 72 hours 19369 NOEC: 50 mg/ L Scientific Name Common Name Test Duration Ref # Concentration Units Sodium Chlorate Appendices  114 tricornutum Phaeodactylum tricornutum Diatom 72 hours 19369 LOEC: 100 mg/ L Phaeodactylum tricornutum Diatom 72 hours 19369 NOEC: 100 mg/ L Phaeodactylum tricornutum Diatom 72 hours 19369 LOEC: 200 mg/ L Phaeodactylum tricornutum Diatom 72 hours 19369 EC50: 298 mg/ L Phaeodactylum tricornutum Diatom 72 hours 19369 EC50: 444 mg/ L Lemna perpusilla Duckweed 7 days 15281 Endpoint Not Reported: 1000000 ug/ L Selenastrum capricornutum Green algae 96 hours 19279 NOEC: 0.75 mM Selenastrum capricornutum Green algae 96 hours 19279 NOEC: >= 0.93 mM Selenastrum capricornutum Green algae 96 hours 19279 LOEC: 0.93 mM Selenastrum capricornutum Green algae 5 days 344 EC50: 133 ppm Scenedesmus quadricauda Green algae 96 hours 17729 NOEC: >= 784 ug/ L Scenedesmus subspicatus Green algae NR 19370 NOEC: 1569 mg/ L Scenedesmus subspicatus Green algae NR 19370 NOEC: 1569 mg/ L Scenedesmus quadricauda Green algae 4 days 607 Endpoint Not reported: 3000 ug/ L Scenedesmus subspicatus Green algae 72 hours 19370 LOEC: > 3137 mg/ L Scenedesmus subspicatus Green algae 72 hours 19370 LOEC: > 3137 mg/ L Scenedesmus subspicatus Green algae NR 19370 LOEC: 3137 mg/ L Scenedesmus subspicatus Green algae NR 19370 LOEC: 3137 mg/ L Scenedesmus subspicatus Green algae 72 hours 19370 NOEC: 3137 mg/ L Scenedesmus subspicatus Green algae 72 hours 19370 NOEC: 3137 mg/ L Sodium Chlorate Appendices  115 Appendix M. Summary of Key Toxicity Studies for This Assessment Sodium Chlorate Appendices  116 Fish MRID 418872 03 Rainbow trout ( 20/ concentration) were exposed to sodium chlorate at 150, 240, 380, 600, and 1000 mg/ L for 96 hours under flow through conditions. Dissolved oxygen was 9.0 to 9.8 mg/ L, pH was 6.8 to 7.3, and the temperature was 11.0 to 11.6 ° C. The NOAEC was 600 mg/ L ( 1/ 20 fish died at 1000 mg/ L). There was evidence that the chlorate concentrations were lower at the end of the study as indicated by a decline in conductivity between days 3 and 4 of the study. Conductivity is directly related to chlorate concentration. Therefore, this study is classified as supplemental.

MRID 418872 02 Bluegill ( 20/ concentration) were exposed to sodium chlorate at 140, 240, 380, 600, and 1000 mg/ L for 96 hours under flow through conditions. Dissolved oxygen was 8.3 to 9.4 mg/ L, pH was 8.0 to 8.7, and the temperature was 21.1 to 22.9 ° C. The NOAEC was 1000 mg/ L. Chlorate concentrations were not analytically confirmed. Also, variability in some of the water quality parameters were observed. This variability, however, did not likely affect the results of this study, and submission of a new study in bluegill would not likely affect the conclusions of this risk assessment. As discussed in Section 3 of this assessment, this study was previously considered invalid by the Agency. Submission of a confirmatory study in daphnids was submitted, which allows this fish study to be upgraded from invalid to supplemental. Therefore, this study is classified as supplemental.

MRID 418872 07 Sheepshead Minnows ( 20/ concentration) were exposed to sodium chlorate at 140, 240, 380, 600, and 1000 mg/ L for 96 hours under flow through conditions. The NOAEC was 1000 mg/ L. Chlorate concentrations were not analytically confirmed. As discussed in this assessment, this study was previously considered invalid by the Agency. Submission of a confirmatory study in daphnids was submitted, which allows this fish study to be upgraded from invalid to supplemental. Therefore, this study is classified as supplemental.

Aquatic Invertebrates MRID 418872 04 Daphnids ( 20/ concentration) were exposed to sodium chlorate at 150, 240, 380, 600, and 1000 mg/ L for 48 hours under flow through conditions. Temperature was 19.5 20.9 B C. Dissolved oxygen was 8.5 9.0 mg/ L, and pH was 7.3 7.7. The NOAEC was 1000 mg/ L. Chlorate concentrations were not analytically confirmed. As discussed in this assessment, this study was previously considered invalid by the Agency. Submission of a confirmatory study in daphnids was submitted, which allows this fish study to be upgraded from invalid to supplemental. Therefore, this study is classified as supplemental.

MRID 438748 01 The 48 hour acute toxicity of sodium chlorate to the water flea was studied under static conditions. Daphnids ( 20/ concentration) were exposed to the test material at mean measured concentrations of 0, 52, 103, 208, 405, and 1019 mg/ L. The EC50 was 920 mg/ L, and the NOAEC was 405 mg/ L based on 55% mortality at 1019 mg/ L. This study is classified as supplemental because the pH and water hardness were outside the range recommended by EPA guidelines. pH could affect the toxicity of chlorate because a reduction product ( chlorite) is particularly toxic to daphnids.

MRID 418872 06 The 96 hour acute toxicity of sodium chlorate to mysid shrimp was studied under flow through conditions. Mysid shrimp ( 20/ concentration) were exposed to sodium chlorate at nominal concentrations of 0, 130, 220, 360, 590, and 1000 mg/ L. Dissolved oxygen was 7.4 to 8.9 mg/ L, pH was 7.6 to 7.8, and the temperature was 21.4 to 23.0* C. 2/ 20 mysids died at 1000 mg/ L, and 1/ 20 died at 590 mg/ L. No other mortalities or signs of toxicity were Sodium Chlorate Appendices  117 noted. This study is classified as supplemental because the test substance concentratins were not analytcally confirmed. This study was previously assigned a classification of invalid; however, as discussed in this assessment, submission of a confirmatory study in daphnids was submitted, which allows this fish study to be upgraded from invalid to supplemental.

MRID 418872 05 Eastern oysters ( 20/ concentration) were exposed to sodium chlorate at nominal concentrations of 0, 70, 120, 250, 500, and 1000 mg/ L for 96 hours under flow through conditions. Temperature was 20 23* C, dissolved oxygen was 7.2 7.5, pH was 7.7 8.0, and salinity was 21 24 ppt ( parts per thousand). EC50 was > 1000 mg/ L. No treatment related mortalities occurred. Shell growth at 250, 500, and 1000 mg/ L was 10%, 15%, and 30% lower than controls, respectively. Shell growth at all other concentrations were equivalent to or greater than controls. Chlorate concentrations were not analytically confirmed. As discussed in this assessment, submission of a confirmatory study in daphnids was submitted, which allows this fish study to be upgraded from invalid to supplemental. Therefore, this study is classified as supplemental.

Aquatic Plants MRID 418872 01 Green algae were exposed to sodium chlorate at nominal concentrations of 0, 62.5, 125, 250, 500, and 1000 mg/ L ( nominal) for 96 hours under flow through conditions. Temperature was 23.5 25.5 B C and pH was 7.2 7.6. The EC50 was 133 mg/ L and the NOAEC was 62.5 mg/ L. This study is classified as Core.

Van Wijk, Kroon, and Irmgard. 1998. Toxicity of chlorate and chlorite to selected species of algae, bacteria, and fungi. Ecotoxicology and Environmental Safety. 40: 206 211. Green algae, brown algae, and blue green algae were exposed to unreported chlorate concentrations for 14 days ( brown and blue green algae) or 96 hours ( green algae). Initial cell density was not reported. Temperature was 22 to 24 B C and pH was maintained at 7.8 to 9. EC50 values were estimated by linear regression. Organisms were grown using either ammonium or nitrate as the sole nitrogen source. The EC50 for brown algae was 0.012 mM to 0.14 mM depending on the nitrogen source. A NOEC was not observed ( effects were observed at the lowest concentrations tested, 0.04 to 0.005 mM). EC50s were not estimated for green algae or blue green algae. The NOEC and LOEC for green algae was 0.75 mM and 0.93 mM, respectively. No effects were observed in bluegreen algae at concentrations up to 3.74 mM.

Terrestrial Plants MRID 463008 01 Vegetative vigor was studied on 10 plant species after application of Sodium chlorate at 348 lb a. i./ A. Test species included buckwheat, corn, cucumber, mustard, oats, onion, radish, sorghum, soybean, and tomato. The 348 lb a. i./ A treatment group percent inhibitions exceeded 25% for the mean fresh weights of all test species. For all test species, almost all plants were dead by 11 days and the phytotoxic effects included chlorosis, necrosis and stunting in the 348 lb a. i./ A treatment group. Cucumber exhibited the greatest reduction for a dicot, with 95.4% mean fresh weight inhibition and sorghum exhibited the greatest reduction for a monocot, with 83.1% mean fresh weight inhibition. The EC25 and NOEC were < 348 lb a. i./ A for all test species. A Tier II study is recommended. This study is classified as Core for a Tier I vegetative vigor study.

MRID 463008 02 Seed germination and seedling emergence were studied on 10 plant species after application of sodium chlorate at 348 lb a. i./ A. Test species included buckwheat, corn, cucumber, mustard, oats, onion, radish, sorghum, soybean, Sodium Chlorate Appendices  118 and tomato. By 5 days in the petri dish bioassay, the 348 lb a. i./ A treatment groups had failed to germinate for all test species compared to the controls. By 14 days, the percent inhibitions for emergence were 10, 3, 97, 81, 5, 0, 27, 21, 8, and 82% for buckwheat, corn, cucumber, mustard, oats, onion, radish, sorghum, soybean, and tomato, respectively, compared to the control. The 348 lb a. i./ A treatment group percent inhibitions exceeded 25% for the mean fresh weights of all test species. For all test species, the phytotoxic effects included chlorosis, necrosis, stunting, and distortion in the 348 lb a. i./ A treatment group. Cucumber exhibited the greatest reduction for a dicot, with 98% mean fresh weight inhibition and corn exhibited the greatest reduction for a monocot, with 90% mean fresh weight inhibition. The EC25 and NOEC for this study was < 348 lb a. i./ A for all test species. A Tier II study is recommended. This study is classified as Core for a Tier I seedling emergence study.

Sodium Chlorite Two toxicity studies using sodium chlorite on non target plants were submitted. These studies were not considered in this assessment on sodium chlorate because non target plant exposure to chlorite from use of sodium chlorate is uncertain, and the relative toxicity of chlorite to chlorate is uncertain. Also, the maximum concentration used in these studies was equivalent to 7.0 lbs ai./ Acre. Chlorate is used at up to 12.5 lbs a. i./ Acre. Nonetheless, a summary of these studies are presented below.

MRID 419485 01 Seed germination (% germination and radicle length) and seedling emergence (% emergence and fresh weight) were studied on 10 plant species after application of Sodium Chlorite at 3.5 ppm ( 7.0 lb a. i./ A). Test species included buckwheat, corn, cucumber, mustard, oats, onion, radish, sorghum, soybean, and tomato. Buckwheat was the only species which exhibited > 25% inhibition, based on reductions in radicle length. In addition to this negative effect, oat and onion radicle length were also significantly reduced in the treatment group ( however, reductions did not exceed 25% for these species). No other species was significantly affected by treatment for radicle length, % emergence, or fresh weight endpoints. The EC25 and NOEC for buckwheat radicle length were < 7 lb a. i./ A. Based on the sensitivity of buckwheat radicle length ( i. e., > 25% reduction), a Tier II study with this species is suggested.

This study is classified as Supplemental. However, this study cannot fulfill the guideline requirements for a vegetative vigor study for sodium chlorate ( Subdivision J, § 122 1 ( TIER I)) because the test substance was not sodium chlorate. Also, missing information needs to be provided to ensure that the study is scientifically sound. Additional water was applied to the soil surface immediately after application in the emergence test ( reportedly to ensure contact of the test chemical with the seed). Chlorite is expected to be very soluble in water and very mobile in soil. Therefore, this watering may have resulted in decreased exposure to chlorite.

MRID 419485 02 Vegetative vigor ( fresh weight) was studied on 10 plant species after application of Sodium Chlorite at 3.5 ppm ( 7.0 lb a. i./ A). Test species included buckwheat, corn, cucumber, mustard, oats, onion, radish, sorghum, soybean, and tomato. The 7.0 lb a. i./ A treatment group percent inhibitions were < 25% for the mean fresh weights of all test species. No mortalities occurred throughout the duration of the test. Chlorosis was observed in three replicates of oats, new leaf distortion was observed in all tomatoes. These observations were observed in treated and control plants. These symptoms were manifested throughout the course of the test for oats and tomatoes. Corn experienced symptoms of nitrogen deficiency during the first week of testing, but these symptoms were not present at the conclusion of the test. The EC25 and NOEC were > 7.0 lb a. i./ A for all test species.

This study is classified as Supplemental. This study cannot fulfill the guideline requirements for a vegetative vigor study for sodium chlorate ( Subdivision J, § 122 1 ( TIER I)) because the test substance was not sodium chlorate. Also, this study did not evaluate some toxicological parameters including dry weight and plant height. In addition, overhead watering used in this study on two occasions could have facilitated chlorite's dissipation and reduced exposure time. Sodium Chlorate Appendices  119 Birds MRID 421494 01 Mallard ducks ( 10/ dose) were administered a single acute oral dose via gavage at 398, 631, 1000, 1590, or 2510 mg/ kg bw. No mortality or signs of toxicity were observed at any dose. This study is classified as acceptable.

MRID 418199 07 Bobwhite quail ( 10/ dose) were maintained on a diet supplemented with sodium chlorate at measured concentrations of 562, 1000, 1780, 3160, or 5620 ppm for 5 days. No mortality or signs of toxicity were observed at any concentration. This study is classified as acceptable.

MRID 418199 08 Mallard ducks ( 10/ dose) were maintained on a diet supplemented with sodium chlorate at measured concentrations of 562, 1000, 1780, 3160, or 5620 ppm for 5 days. No mortality or signs of toxicity were observed at any concentration. This study is classified as acceptable.

Mammals Acute exposures In an acute oral toxicity study ( MRID 41819901), groups of fasted, young adult Sprague Dawley albino rats ( 5/ sex) were given a single oral dose of sodium chlorate crystal ( 100 % a. i., batch/ lot DL 1) in 50% w/ w solution of distilled water at doses of 2 or 5 g/ kg bw and observed for 14 days. These doses were based on a range finding study of 1 rat/ sex dosed at 0.3, 0.6, 1.25, 2.5, or 5.0 g/ kg bw, where there no mortalities observed. Oral LD50 is equal or greater than 5000 mg/ kg bw ( both sexes). Sodium chlorate is of SLIGHT oral Toxicity based on the oral LD50 in males and females ( Toxicity Category IV). All animals in the 2 g/ kg group survived with only transient hunched posture in one male 2 4 hours post dosing. In the 5g/ kg dose, one female died one day after dosing. Several other animals appeared lethargic and had hunched posture shortly after exposure that lasted for the first 24 hours. Necropsy findings of the dead female showed green discoloration of the intestine, a light green fluid on the stomach, pink liquid in the abdominal cavity and dark red lung discoloration. Necropsy findings of the survivors were unremarkable. This acute oral toxicity study is classified acceptable/ guideline. This study satisfies does satisfy the guideline requirement for an acute oral toxicity study on the technical material ( OPPTS 870.1100; OECD 401) in the rat. Other acute studies are summarized in Table M 1 below. Sodium Chlorate Appendices  120 Table M 1. Acute Toxicity Profile in Mammals Guideline No./ Study Type Study Type  Species MRID No. Results 870.1100 Acute oral  Rats 41819901 5000 mg/ kg ( rat)

870.1200 Acute dermal  Rabbits 41819902 42497601 LD50 = > 2000 mg/ kg ( dry crystal) LD50 = > 2000 mg/ kg ( moistened)

870.2400 Acute eye irritation  Rabbit 00085090; 00102998 41819904 mildly irritating mildly irritating 870.2500 Acute dermal irritation  Rabbit 41819905 42497602 non irritating ( dry crystal) minimally irritating ( moistened) Sodium Chlorate Appendices  121 Table M 2. Summary of Selected Repeated Dose Toxicity Studies Using Sodium Chlorate in Laboratory Animalsa Guideline No./ Study Type MRID No. ( year)/ Classification / Doses Results 870.3100 90 Day oral toxicity ( Sprague Dawley Rats)

Non Guideline 90 Day oral toxicity ( Sprague Dawley Rats)

Non Guideline 90 Day oral toxicity ( F344 rats and B6C3F1 mice) 40444801( 1997) Acceptable/ guideline 0, 10, 40, 100 or 1000 mg/ kg/ day, oral gavage McCauley et al, 1995 SD rats ( 10/ sex/ group) NaClO3 in the drinking water 3.0, 12.0, or 48 mM for 90 days M: 30, 100 and 512 mg/ kg/ day F: 42, 158, and 800 mg/ kg/ day Hooth et al, 2001 NaClO3 in drinking water at 0, 0.125, 0.25, 1.0 or 2 g/ L for 21 days or 90 days in rats and mice M: 14, 28, 112, 225 mg/ kg/ day F: 20, 40, 160 mg/ kg/ day at 0, 0.5, 1.0, 2.0, 4.0, or 6 g/ L NOAEL = 100 mg/ kg/ day LOAEL = 1000 mg/ kg/ day based on hematological effects ( hemoglobin concentration, hematocrit, RBC counts were statistically significantly decreased, and reticulocyte count was statistically significantly increased in females. In males, only the hematocrit was statistically significantly decreased. The adrenal weight was depressed in both males and females.

NOAEL = 30 and 42 mg/ kg/ day in males and females. LOAEL = 100 mg/ kg/ day in males and 150 mg/ kg/ day in females, based on the pituitary effects ( vacuolization) and thyroid gland effects ( colloid depletion), the body weight decrease and organ weight changes and reduction in erythrocyte counts and hemoglobin content.

NOAEL = 0.25 g/ L ( 28 & 40 mg/ kg/ day for males and females, respectively) LOAEL = 1.0 g/ L based on colloid depletion and follicular cell hyperplasia, ( 112 & 160 mg/ kg/ day for males and females, respectively) Total serum triiodothyronine ( T3) and thyroxine ( T4) concentrations were decreased significantly and TSH levels increased significantly in male and female rats after 4 days of treatment with 1.0 or 2.0 g/ L and after 21 days of treatment with 2.0 g/ L. TSH levels also increased significantly in male rats after 21 days of treatment with 1.0 g/ L. Serum T3 and T4 levels were comparable to controls in male and female rats after 90 days of treatment, but TSH levels were increased in both sexes. Follicular cell hyperplasia was not present in male or female mice. Table M 2. Summary of Selected Repeated Dose Toxicity Studies Using Sodium Chlorate in Laboratory Animalsa Guideline No./ Study Type MRID No. ( year)/ Classification / Doses Results Sodium Chlorate Appendices  122 870.3150 90 Day oral toxicity ( Beagle Dogs) MRID 40460402 ( 1987) Acceptable/ Guideline oral gavage 0, 30, 60 or 360 mg/ kg/ day for 90 d NOAEL = 360 mg/ kg/ day ( HDT) LOAEL = greater than 360 mg/ kg/ day based on lack of detectable adverse effects. Higher dose levels were not possible due to occurrence of emesis at higher doses. Non Guideline subacute study in dogsHeywood et al, 1972 doses of 200 to 326 mg/ kg/ day of sodium chlorate administered daily by intubation as 50 ml of 6% solution to 8 dogs for 5 days sodium chlorate caused reduction of packed cell volume, hemoglobin and red blood cells. A consistent increase in plasma urea concentration was also observed. Two animals that received 308 or 326 mg/ kg/ day suffered appetite loss, body weight decline and appearance of blood in their urine or feces. One of the animals died after 4 days of exposure. Postmortem examination of both animals revealed typical signs of chlorate poisoning, including cyanotic kidney surface and evidence of necrosis and hemolysis in the kidney. Five of the 8 animals displayed tissue pathology indicative of hemolysis such as Kupffer cells containing brown pigment.

Non Guideline 21 day oral toxicity study ( B6C3F1 mice) NTP Study ( 1999a) 10/ sex/ dose: 0, 125, 500, 1000 or 2000 mg/ L M: 22, 43, 173 or 348 mg/ kg/ day 0, 20, 44, F: 94, 192 or 363 mg/ kg/ day Sodium chlorate had no effect on survival, body weights, clinical signs, water consumption, hematology parameters, methemoglobin concentration, or organ weights of either sex. There were no gross or microscopic lesions that were considered to be due to sodium chlorate treatment.

Non Guideline 21 day oral toxicity study ( Fisher 344 rats) NTP Study ( 1999b) 10/ sex/ dose: 0, 125, 500, 1000 or 2000 mg/ L M: 0, 20, 36, 77 or 170 mg/ kg/ day F: 0, 21, 38, 73, 152 or 338 mg/ kg/ day Sodium chlorate had no effect on survival, body weights, clinical signs or water consumption. A moderate to severe neutropenia was observed in both sexes on day 4 and 22. Very mild decreases in erythrocyte counts, hemoglobin, and hematocrit were considered not to be biologically significant. The only gross or microscopic lesion that was considered to be treatment related was a minimal to mild follicular cell hyperplasia of the thyroid gland seen in males at 500 mg/ L or greater and in females at 250 mg/ L or greater.

870.3700a Prenatal developmental ( rats) MRID 40460401( 1987) Acceptable/ Guideline oral gavage 0, 10, 100 or 1000 mg/ kg/ d on GD 6 15 Maternal NOAEL = 1000 mg/ kg/ day ( HDT) LOAEL = > 1000 mg/ kg/ day. Developmental NOAEL = 1000 mg/ kg/ day ( HDT) LOAEL = > 1000 mg/ kg/ day based on lack of effects Table M 2. Summary of Selected Repeated Dose Toxicity Studies Using Sodium Chlorate in Laboratory Animalsa Guideline No./ Study Type MRID No. ( year)/ Classification / Doses Results Sodium Chlorate Appendices  123 870.3700b Prenatal developmental ( Rabbits) NTP ( 2002) Acceptable/ Guideline 0, 100, 250, or 475 mg/ kg/ d on GD 6 29. Range finding study: 0, 100, 250, 500, 750 or 1000 mg/ kg/ d Maternal NOAEL = 475 mg/ kg/ day ( HDT) LOAEL = 500 mg/ kg/ day based on mortality in range finding study. Developmental NOAEL = 475 mg/ kg/ day ( HDT) LOAEL = > 475 mg/ kg/ day a Data compiled by the Health Effects Division of EPA.