Ecological Effects and Endangered Species Risk Assessment for Choline Chloride

Choline chloride a quaternary ammonium salt is miscible with water in all proportions and has a 

measured water solubility of 650 g/L. Due to the measured and calculated log Kow of –3.77 and 

–5.15, respectively, and the calculated log Koc of 0.37, bio- and geoaccumulation are not to be 

expected. Choline chloride was shown to be readily biodegradable according to OECD criteria in 

a MITI I-Test within 14 days. In the atmosphere, the substance will be rapidly indirectly 

photodegraded by reaction with OH-radicals (calculated t 1⁄2 = 6.9 h) based on a 12h-day.

Terrestrial Species

The Agency has estimated potential acute toxicity end points for avian and mammalian species 

(LD50 = 3,129 mg/kg) and calculated potential risk using the Terrestrial Residue Exposure Model 

(T-REX) Version 1.4.1 for the orchard spray application of CP Bio, Choline Chloride 20% SP at 

the maximum rate of 0.282 lbs ai/A (Appendix B). The T-REX model using Kenega values 

produced low dose-based values and risk quotients (RQs) that were at least one to two orders of 

magnitude (0.00 – 0.06) below the EPA Levels of Concern (LOC) of 0.1 for avian and 

mammalian endangered species. The possible effect to honey bees is also very low with an 

LD50> 89 ug ai/bee (RQ < 0.09). The Agency also conducted a search (10/09/2015) of the 

Ecological Incident Information System version 2.1.1 (EIIS) and did not find any reports of 

detrimental exposure of choline chloride to terrestrial species. This low risk to non-target 

terrestrial species suggests that the potential for toxic exposure to endangered/ threatened species 

is also very low. The Agency calculated the chance of individual terrestrial exposure and risk by

using the Individual Effects Chance Model (Version 1.1) which suggest that the chance of effects 

to a terrestrial species from choline chloride exposure is about 1 in 2,940,000 (predictor of 

chance of individual effect using Probit dose-response curve slope and median lethal estimate

Appendix C) which may be considered as a highly unlikely event. The low toxic risk of choline 

chloride to terrestrial organisms (RQ = 0.0 – 0.6), the short environmental half-life (7 days), the 

low maximum concentration of choline chloride to be applied per season (128.0 g/A), and an 

understanding of the mode of action of this compound (plant growth regulator) show that there is 

a very low potential for toxic risk to terrestrial species. Based on the proceeding information, 

choline chloride presents a No Effect (NE) to threatened or endangered terrestrial species, 

if used in accordance with approved labeling.

Aquatic Species

Choline chloride is very water soluble (690 g/L) but exposure to aquatic species is not expected 

to result in acute toxicity. The Agency conducted a worst case scenario using the aquatic model 

FIRST Ver 1.1.1 to assess the potential exposure of runoff and drift from the maximum 

application of choline chloride formulation to an aquatic area (Appendix A). Using the EPA 

LOC values for aquatic listed species (0.05), the expected peak estimated environmental 

concentration of 0.060 ppm, and assuming that 0.282 lbs ai/A, RQ values were calculated at 0.00 

showing no acute toxicity risk to aquatic species. The Agency conducted a search (10/09/2015) 
of the Ecological Incident Information System (EIIS, version 2.1), the ‘Aggregate Incident 

Reports’ (v. 1.0) database, for ecological incidents involving choline chloride and no aquatic 

incidents were reported. The Agency also calculated the chance of individual fish and aquatic 

invertebrate exposure and risk by using the Individual Effects Chance Model (Version 1.1). 

These calculations suggest that the chance of effects to aquatic invertebrates (food source) or to 

fish from methyl choline chloride is about 1 in 418,000,000 (Appendix C), which may be 

considered as a highly unlikely event. Therefore, the Agency concludes a No Effect (NE) to 

aquatic endangered/ threatened species because of the lack of potential for direct or indirect 

toxic risk to aquatic ecological systems from exposure to choline chloride.

Plants (Aquatic and Terrestrial)

Concentration levels of choline in plants can range from 28 – 589 ppm. The environmental 

residue levels of choline chloride after direct application to foliage were calculated from the TRex model and showed a range of 7.93 – 126.90 ppm. According to the assumptions of the EPA 

FIRST Ver. 1.1.1 aquatic model there is an expected 8% drift from orchard spraying that could 

result in 0.63 – 10.15 ppm residues onto adjacent vegetative sites. These expected environmental 

concentration to non-target plants are at or below the background levels found in plants. Choline 

chloride is non-toxic to plants and any indirect effects to non-target plants that could be 

considered habit for endangered/threatened species is expected to be No-Effect.

Conclusion

The unique characteristics of this product, choline chloride, the non-toxic mode of action (plant 

growth regulator), biodegradability (7 day half-life), photo degradation (6.9 hours), no 

bioaccumulate (Log Koc = 0.37) and low potential for exposure (maximum application of 0.282 

lbs ai/A 4 times /season) will result in no acute direct or indirect toxic risk to non-target 

organisms, including threatened and endangered species. Based on the proceeding information, 

choline chloride presents a No Effect (NE) to threatened or endangered terrestrial or 

aquatic species (plants or animals), if used in accordance with approved labeling.
References

MOE Japan (1999). Ministry of Environment. Acute toxicity study of choline chloride on the

freshwater alga Pseudokirchneriella subcapitata unpublished study. No. 1998-13.

BASF AG (2003). Department of Product Safety. Laboratory of Ecology. Hemmung der

Algenzellvermehrung nach DIN 38412 L9: "78% choline chloride dissolved in water". 

Unpublished data. Reprint of report No. 09908 (06 Nov 1989). 16 Sept. 2003.
Appendix A.0 Calculate Water Concentrations for Choline Chloride using FIRST Ver 1.1.1 

MAR 26, 2008

Table A.1 Water Concentration for Choline Chloride after Application to Stone Fruits at 

0.282 lbs/A 

 -------------------------------------------------------------------------------------------------------------------

 RATE (#/AC) No. APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP

 ONE (MULT) INTERVAL Koc (PPM) (%DRIFT) AREA (IN)

 -------------------------------------------------------------------------------------------------------------------

 0.282 (0.722) 4 7 0.4 ******* ABLAST (6.3) 87.0 0.0

 FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

 --------------------------------------------------------------------

 METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED

 (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.)

 -----------------------------------------------------------------------------------------------------------------------

 14.00 0 14 0.29- 35.96 14.00 10.08

 UNTREATED WATER CONCENTRATION (PPB)) 

 --------------------------------------------------------------------

 PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)

 ------------------------------------------------------------------------------------------------------------

 60.101 1.792

 
Appendix B.0 T-REX Output for Choline Chloride Exposure to Avian and Mammalian 

Species after 

Table B.1 Terrestrial Residue Exposure Model (T-REX) Version 1.4.1 Application to Stone 

Fruit 

Chemical Name:

 Use

 Formulation

Application Rate 0.282 lbs a.i./acre

Half-life 7 days

Application Interval 7 days

Maximum # Apps./Year 4

Length of Simulation 1 year

Variable application rates? no

Bobwhite quail LD50 (mg/kg-bw) 3129.00

Bobwhite quail LC50 (mg/kg-diet) 0.00

Mallard duck NOAEL(mg/kg-bw) 0.00

Bobwhite quail NOAEC (mg/kg-diet) 0.00

3129.00

0.00

0.00

0.00

Kenaga

Values

Short Grass 126.90

Tall Grass 58.16

Broadleaf plants 71.38

Fruits/pods/seeds 7.93

Arthropods 49.70

Endpoints

 Upper Bound Kenaga Residues For RQ Calculation

Dietary-based EECs (ppm)

NOAEL (mg/kg-bw)

NOAEC (mg/kg-diet)

Mammals

LD50 (mg/kg-bw)

LC50 (mg/kg-diet)

Choline chloride

stone fruits

CP Bio Choline Chloride

Avian
Avian Results

Avian Body Ingestion (Fdry) Ingestion (Fwet) % body wgt FI

Class Weight (g) (g bw/day) (g/day) consumed (kg-diet/day)

Small 20 5 23 114 2.28E-02

Mid 100 13 65 65 6.49E-02

Large 1000 58 291 29 2.91E-01

20 5 5 25 5.06E-03

Granivores 100 13 14 14 1.44E-02

1000 58 65 6 6.46E-02

Avian Body Adjusted LD50

Weight (g) (mg/kg-bw)

20 2254.22

100 2869.74

1000 4053.62

small mid large

20 100 1000

Short Grass 144.53 82.42 36.90

Tall Grass 66.24 37.77 16.91

Broadleaf plants 81.30 46.36 20.76

Fruits/pods 9.03 5.15 2.31

Arthropods 56.61 32.28 14.45

Seeds 2.01 1.14 0.51

20 100 1000

Short Grass 0.06 0.03 0.01

Tall Grass 0.03 0.01 0.00

Broadleaf plants 0.04 0.02 0.01

Fruits/pods 0.00 0.00 0.00

Arthropods 0.03 0.01 0.00

Seeds 0.00 0.00 0.00

Dietary-based RQs 

(Dietary-based EEC/LC50 or 

Acute Chronic

Short Grass #DIV/0! #DIV/0!

Tall Grass #DIV/0! #DIV/0!

Broadleaf plants #DIV/0! #DIV/0!

Fruits/pods/seeds #DIV/0! #DIV/0!

Arthropods #DIV/0! #DIV/0!

Dose-based EECs 

(mg/kg-bw) 

Avian Classes and Body Weights (grams)

Dose-based RQs 

(Dose-based EEC/adjusted LD50)

RQs

Avian Acute RQs

Size Class (grams)
The application of CP Bio, Choline Chloride 20% SP at the maximum rate of 0.282 lbs ai/A does 

not pose an acute risk to nontarget or threatened avian or mammalian species. Risk quotients 

(RQs) were generated using the acute mammalian LC50 = 3,129 mg/kg. The T-REX model using 

Kenega values produced low dose-based values and RQs that were at least one to two orders of 

magnitude (0.00 – 0.06) below the EPA Levels of Concern (LOC) of 0.1 for avian and 

mammalian endangered species.

Mammalian Results

Mammalian Body Ingestion (Fdry) Ingestion (Fwet) % body wgt FI

Class Weight (g bwt/day) (g/day) consumed (kg-diet/day)

15 3 14 95 1.43E-02

Herbivores/ 35 5 23 66 2.31E-02

insectivores 1000 31 153 15 1.53E-01

15 3 3 21 3.18E-03

Grainvores 35 5 5 15 5.13E-03

1000 31 34 3 3.40E-02

Mammalian Body Adjusted Adjusted

Class Weight LD50 NOAEL

15 6877.01 0.00

Herbivores/ 35 5564.24 0.00

insectivores 1000 2406.70 0.00

15 6877.01 0.00

Granivores 35 5564.24 0.00

1000 2406.70 0.00

15 35 1000

Short Grass 120.99 83.62 19.39

Tall Grass 55.45 38.33 8.89

Broadleaf plants 68.06 47.04 10.91

Fruits/pods 7.56 5.23 1.21

Arthropods 47.39 32.75 7.59

Seeds 1.68 1.16 0.27

15 grams 35 grams 1000 grams

Acute Chronic Acute Chronic Acute Chronic

Short Grass 0.02 #DIV/0! 0.02 #DIV/0! 0.01 #DIV/0!

Tall Grass 0.01 #DIV/0! 0.01 #DIV/0! 0.00 #DIV/0!

Broadleaf plants 0.01 #DIV/0! 0.01 #DIV/0! 0.00 #DIV/0!

Fruits/pods 0.00 #DIV/0! 0.00 #DIV/0! 0.00 #DIV/0!

Arthropods 0.01 #DIV/0! 0.01 #DIV/0! 0.00 #DIV/0!

Seeds 0.00 #DIV/0! 0.00 #DIV/0! 0.00 #DIV/0!

Dose-Based EECs 

(mg/kg-bw)

(grams)

Mammalian Classes and Body weight

Medium mammal Large mammal Dose-based RQs 

(Dose-based EEC/LD50 or 

Small mammal
Appendix C.0 Individual Effects Chance Model for Terrestrial and Aquatic Species

Table C.1. Individual Effects Chance Model Version 1.1 for Predicting the Chance of 

Individual Effects of Choline Chloride to Terrestrial Endangered Species

IEC V1.1 - Individual Effect Chance Model Version 1.1

Predictor of chance of individual effect using Probit dose-response curve slope and median lethal estimate 

Enter LC50 or LD50 3129

Enter desired threshold 0.1

Enter slope of dose-response 4.5

z score result -4.5

Probability associated with z 3.40E-06

Chance of individual effect, ~1 in . . . 2.94E+05

Table C.2. Individual Effects Chance Model Version 1.1 for Predicting the Chance of 

Individual Effects of Choline Chloride to Aquatic Endangered Species

IEC V1.1 - Individual Effect Chance Model Version 1.1

Predictor of chance of individual effect using Probit dose-response curve slope and median lethal estimate 

Enter LC50 or LD50 100

Enter desired threshold 0.05

Enter slope of dose-response 4.5

z score result -5.85463498

Probability associated with z 2.39E-09

Chance of individual effect, ~1 in . . . 4.18E+08
Appendix D.0 Calculated RQ Values

Table D.1 Summary of Specific Ecological Assessment Endpoints and Calculated RQ 

Values for Terrestrial and Aquatic Species Exposed to Choline Chloride after Application 

to Stone fruits

TAXA MEASURE OF EFFECT

Species Toxicity RQ

Freshwater Fish Acute

Rice fish (Oryzias latipes) 96 hr LC50 > 100 mg/L 0.00

Freshwater 

Invertebrates

Acute

Daphnia magna EC50 =349 mg/L 0.00

Avian Acute

Mallard duck 

(Anas platyrhynchos)

a

LD 50 = 3,129 mg ai/kg

0.00 – 0.6

Mammals Acute

Rat

(Rattus norvegicus)

LD50 = 3,129 mg/kg 0.00 – 0.2

Insect Acute

Honey bee 

(Apis mellifera) LD50 > 89 ug ai/bee < 0.09

a The mammalian acute toxicity data is used as a surrogate for avian oral dose