UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON. D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

March 18, 2014 

PC Code: 0601 01 and 0601 02 

DP Barcode: 415548 

SUBJECT: 

FROM: 

Problem Formulation for the Ecological Risk and Drinking Water Exposure 

Assessments to be Conducted in Support of the Registration Review of 

Thiabendazole and its Hypophosphite Salt 11 11 , ....J--11-- ~ry~ Nicholas Mastrota, Ph.D., Wi'ldlife Biologist 

James K. Wolf, Ph.D., Environmental Scientist 

Environmental Risk Branch 3 

Environmental Fate and Effects Division (7507P) 

~LJrl 

Srinivas 

William 

Gowda, 

Erickson, 

Microbiologist 

Ph.D., Biologist 

S -n h)~ ~ V D)>, ~ 

Najm Shamim, Ph.D., Chemist ;1~ a• '""" 

Risk Assessment and Science Support Branch (RASSB) 

Antimicrobials Division (751 OP) 

REVIEWED Rosanna Louie-Juzwiak, Risk Assessment Process Leader ~--T-- BY: Melissa Panger, Ph.D., Senior Biologist 

James Hetrick, Ph.D., Senior Advisor 

Environmental Risk Branch 3 

Environmental Fate and Effects Division (7507P) 

THROUGH: Dana Spatz, Branch Chie~ <:::::::::::: h 3.-1 ~ "' I '-/ 

·Environmental 

Environmental F

Risk 

ate and 

Bran~h Effects ~~ 

Division (7507P) 

Steven Weiss, Branch Chief ~ {JI~, Risk Assessment and Science Support Branch (RASSB) 

Antimicrobials Division (7 51 OP) 

TO: Neil Anderson, Branch Chief 

Ricardo Jones, Chemical Review Manager 

Risk Management and Implementation Branch I 

Pesticide Re-Evaluation Division (7508P) 

1 
2 

1. Executive summary 

The Environmental Fate and Effects Division (EFED) and Antimicrobials Division (AD) have 

completed the preliminary problem formulation for the ecological risk, environmental fate, 

endangered species, and drinking water assessments to be conducted as part of the registration 

review of the systemic fungicide thiabendazole (PC code: 060101) and the related salt, 

thiabendazole hypophosphite (060102), hereon referred to as thiabendazole. The problem 

formulation describes the methods planned to be used during the completion of drinking water 

and ecological risk assessments in support of registration review, and provides an overview of 

the environmental fate, ecological effects, and potential risks associated with the use of 

thiabendazole. Uncertainties unique to the risk assessment of thiabendazole are also discussed. 

Although no data have been submitted for thiabendazole hypophosphite, this assessment 

considers that the salt will dissociate rapidly to form thiabendazole in water. 

The following additional information is needed to better understand the environmental fate of 

thiabendazole: 

 Metabolism rates, identification of degradation products, and sorption/desorption in spent 

mushroom compost before and after pasteurization. 

 Additional information concerning the fate of the spent mushroom compost such as 

residue concentrations, amounts produced, and rates applied as a soil amendment. 

 Information estimating of the amount of thiabendazole released in the wastewater 

effluent from the manufacturing plants during the manufacturing process would be 

beneficial to refine the risk assessment. A ready biodegradability study is also 

anticipated to be required (835.3110). If the ready biodegradability study indicates that 

thiabendazole is not biodegradable, then one of three biodegradation in active sludge 

simulation tests is anticipated to be required, being either GLN 835.3220, 835.3240, or 

835.3280. 

The following additional data are needed for conducting the ecological risk assessment: 

 Acute oral toxicity to a passerine bird (GLN 850.2100) 

 Toxicity to a freshwater and saltwater diatom (GLN 850.4500) 

 Toxicity to cyanobacteria (GLN 850.4550) 

 The Environmental Chemistry Methods (ECM) and Independent Laboratory Validation

(ILV) are needed for water (GLN 850.6100). 

 An Activated Sludge, Respiration Inhibition Test (ASRI) is needed to determine the 

effects of thiabendazole on wastewater treatment plant organisms (GLN 850.3300). 

 A leaching study from treated textiles is needed to assess the textile uses. 

While a life-cycle study with the saltwater mysid (GLN 850.1350) would reduce uncertainty in 

the risk assessment, EPA intends on estimating toxicity using the acute-to-chronic ratio method. 

 
3 

2. Introduction 

EPA evaluated the most recent ecological risk assessments for thiabendazole in association with 

the updated toxicity, exposure, and usage information to determine if sufficient data are available 

and if further updates are needed to support registration review. Recent conventional uses risk 

assessments include assessments for a seed-treatment use on corn (field corn, sweet corn, and 

popcorn) (USEPA, 2010; DP barcode: D363978); a seed-treatment use on dry peas (dry peas, 

lentils, and chickpeas) (USEPA, 2006; DP barcodes: D315436, D322581); and an assessment 

conducted for the re-registration evaluation decision (RED) of thiabendazole (USEPA, 1999); 

see Use Characterization section for additional uses of thiabendazole. In addition, EPA 

considered the latest science policies and risk assessment methodologies. 

The structures of thiabendazole and thiabendazole hypophosphite are given in Figure 1. 

Chemical names and other identifiers of thiabendazole and degradates can be found in Table 5. 

 a. Thiabendazole Structure 

b. Thiabendazole hypophosphite 

Figure 1. Thiabendazole (a.) and thiabendazole hypophosphite (b.) 

Mechanism of Action 

Thiabendazole is a systemic fungicide. The mode of action of thiabendazole inhibits the mitosis 

of plant pathogenic fungi species by preventing the polymerization of beta-tubulins. Because 

dimers of beta-tubulin and alpha-tubulin polymerize to form microtubule structures inside the 

cells, thiabendazole acts as an inhibitor of microtubuline polymerization, terminating cell 

division. 
4 

3. Use Characterization 

Conventional Uses: Thiabendazole is registered for use as a seed treatment on seeds of corn 

(field corn, sweet corn, and popcorn), soybean, dry peas, chickpeas, lentils, and wheat; a 

treatment of seed pieces of potatoes and sweet potatoes; and as a postharvest application to a 

variety of terrestrial food and non-food crops (e.g., potatoes, citrus, pome fruit, ornamentals, turf, 

and tobacco). Thiabendazole is also registered for use in mushroom culture for control of fungal 

diseases. It is applied to seeds and seed pieces as a ready-mix or as a slurry mix. It is sprayed 

onto mushrooms as a flowable concentrate. Thiabendazole hypophosphite, a salt of 

thiabendazole, is used as a tree-injection fungicide in ornamental trees. 

Application rates for seed treatments are given in terms of weight of thiabendazole applied to 

weight of seed. Application rates range from 0.000055 to 0.0028 pound active ingredient (a.i.) 

per pound of seed. EFED estimates upper bound application rates in terms of pounds a.i. per acre 

treated by multiplying these pounds-per-seed rates by maximum expected seed planting rates 

(seeds per acre), which is specific for each crop. Use information provided on the labels for 

thiabendazole seed treatment is given in Table 1. 

Table 1. Application Information for Seed Treatment Uses of Thiabendazole

Seed Type 

Maximum AI 

Application Rate 

(lb a.i./100 lb seed) 

Maximum Seeding 

Rate (lb seed/Acre) 

Max Application 

Rate 

(lb a.i./A) 

Clover 0.283 30.0 0.0849 

Corn, field 0.0200 29.6 0.00593 

Corn, pop 0.042 22.0 0.00974 

Corn, sweet 0.0355 33.2 0.0118 

Garbanzos (including chickpea) 0.0663 217.8 0.0144 

Lentil 0.0341 163.4 0.0558 

Peas, garden 0.0332 411.0 0.136 

Peas, dry 0.0332 217.8 0.0722 

Pea, pigeon 0.0332 43.6 0.0145 

Potato seed-pieces 0.0006722 6969.63 0.0468 

Soybean 0.00548 166.7 0.00913 

Sweet potato seed pieces ND1

Wheat (spring and winter) 0.131 156.0 0.20 

 1 Product labels do not provide enough information to calculate the application rate for sweet potato seed pieces. 2 0.42 fl oz. product/2000 pounds potatoes 

 3 4900-6969 lb potato seed pieces/A; The maximum seeding rate was developed based on data provided by 

BEAD—J. Becker; S. Ratnayake. Acres Planted per Day and Seeding Rates of Crops Grown in the United 

States, March 24, 2011 

Thiabendazole may be applied to mushrooms at the casing, fuzzing, pinning stages, and between 

harvests of mushroom breaks. It may be applied to mushrooms to a maximum rate of 0.641 lb 

a.i./1000 ft2 (20 fl oz Mertect® 340-F [EPA Reg. No 100-889] per 1000 ft2) per crop cycle. The 

first application may be made up to 0.256 lb a.i./1000 ft2

 (8 fl oz Mertect® 340-F per 1000 ft2), 

and subsequent applications may be made up to 0.128 lb a.i./1000 ft2

 (4 fl oz Mertect 340-F per 

1000 ft2). Although application of thiabendazole in mushroom culture takes place indoors, after 
5 

the mushrooms are harvested, the spent compost on which thiabendazole was sprayed may be 

disposed of outdoors, or used as a mulch or soil amendment. This outdoor application of spent 

mushroom compost could result in release of thiabendazole residues into the environment. 

Thiabendazole may be applied to mushrooms at any time during cultivation from spawning 

through 12 hours prior to mushroom harvest. Since mushrooms are grown indoors with closed 

irrigation systems, no appreciable exposure to the outdoor environment is expected during the 

time of culture. However, after a cycle of mushroom harvest is complete, the spent mushroom 

compost (SMC) is commonly collected and sold to distributers for use as a landscape and 

horticulture product. The SMC may then be applied to the surface of soil as a mulch, or mixed 

into farm or garden soil as a soil amendment.1

 Residues of thiabendazole that accumulated 

during mushroom cultivation potentially could remain in the SMC and be released into the 

environment at this time. Grogan and Jukes (2003) found that thiabendazole is highly persistent 

in mushroom casing soil, and thus some thiabendazole residues are expected to persist in SMC. 

Thiabendazole hypophosphite, a salt of thiabendazole, is used as a tree-injection fungicide for 

control of certain fungal diseases in elms, London plane, oak, and sycamore trees. Products 

containing thiabendazole hypophosphite are formulated as a soluble concentrate or a ready-touse solution. They are applied by injection into sapwood of root flares of the tree. The maximum 

application rate for large trees is approximately 94 g (0.21 lb) of active ingredient per 5 inches of 

trunk diameter. For trees less than 30 inches in diameter, the maximum application rate is 

approximately 63 g (0.14 lb) of active ingredient per 5 inch of trunk diameter. The rates in terms 

of thiabendazole equivalence are 71 g (0.16 lb) thiabendazole per 5 inches of diameter for large 

trees and 47 g (0.10 lb) thiabendazole per 5 inches of diameter. Trees may be retreated once 

every three years. 

Antimicrobials Uses: Thiabendazole is registered for use as a material preservative and 

antifungal agent to inhibit the growth of mold and mildew associated with odors, staining, 

discoloration, and general biodeterioration on adhesive films, wallpaper adhesives, interior and 

exterior latex or solvent/oil based paint films, stains, paper products, heating and cooling system 

filters and/or room air cleaners/purifiers, wallboard, sealants, grout, ceiling tiles, plastics, plastic 

intermediates, canvas textiles, and carpet backing, and natural and synthetic fibers. 

4. Conclusions from Previous Risk Assessments 

a. Ecological Risk Assessment 

Ecological risk assessments have been conducted for seed treatment uses of thiabendazole, but 

not for the mushroom use, nor for the tree-injection use of thiabendazole hypophosphite. 

Ecological risk assessments have also not been conducted for the antimicrobial uses 

(paints/stains, textiles). The ecological risk assessment conducted in the RED for seed treatment 

uses concluded that there were minimal potential risks from thiabendazole to terrestrial or 

aquatic animals (USEPA, 1999). Plants were not assessed in the RED; however, risk was not 

expected based on the low exposure potential for the uses registered at the time of the 

 

1 http://extension.oregonstate.edu/gardening/what-mushroom-compost
6 

assessment. In the ecological risk assessment conducted for thiabendazole use as a seed 

treatment on dry peas, no risks to terrestrial or aquatic animals were expected (USEPA, 2006). 

Although there were no effects noted at the highest concentrations tested in the available avian 

reproduction studies, there was some uncertainty related to chronic risk for birds from the 

chickpea use because the estimated environmental concentrations were higher than the highest 

concentration tested. Additionally, risks to aquatic and terrestrial plants could not be assessed 

due to a lack of data. 

The most recent, comprehensive assessment conducted for thiabendazole is the assessment 

conducted for the new use of corn seed treatment (USEPA, 2010) and the new use on dry peas 

(USEPA, 2006). The risk assessment for seed treatment of corn with a maximum seasonal 

application rate of 0.005 lb a.i./A concluded that acute and chronic risks were less than the 

EPA’s levels of concern (LOC) for fish, aquatic invertebrates, birds, and mammals. The risk 

assessment for seed treatment of dry peas with a maximum seasonal application rate of 0.09 lb 

a.i./A concluded that acute and chronic risks were less than the EPA’s LOCs for fish, aquatic 

invertebrates, and mammals. For birds, acute risk was less than the LOC whereas chronic risk 

was above the LOC. Potential chronic risk for birds was concluded, but uncertainties in this 

conclusion were noted due to limitations with the available avian reproduction data and the 

conservative nature of the chronic risk assessment. In both assessments, risks to aquatic plants, 

terrestrial plants, and terrestrial arthropods could not be assessed because toxicity data were 

lacking for these groups of organisms. 

As noted above, previous risk assessments have not included evaluation of the use of 

thiabendazole on mushrooms or tree-injection uses of thiabendazole hypophosphite. Therefore, 

the potential risks from these uses are unknown. EFED expects that the tree-injection uses result 

in limited ecological risks because this use would mainly expose terrestrial animals, and 

thiabendazole has relatively little toxicity to terrestrial animals. However, there is uncertainty 

regarding risk from use in mushroom culture, and exposures from application of spent mushroom 

compost, could potentially be much greater than that for seed treatment uses. When considering 

the application rate expressed in terms of pounds a.i./acre, exposure would be at least 10 times 

greater than those for seed treatments, and the high persistence of thiabendazole which suggest 

that it would likely accumulate and persist in the mushroom compost. 

The major ecological concerns based on previous risk assessment are summarized in Table 2: 

Table 2. Summary of Risk Concerns Identified for Thiabendazole in Previous Assessments 

Birds Mammals Terr. 

Plants 

Terr. 

Inverts Fish BCF Aquatic Inverts 

Aquatic 

Plants 

Groundwater 

Contamination Persistence Degradates of Concern 

Yesa Nob Noc Noc ?b No ?b Noc No Yes No a

 Potential chronic risk to birds was identified for some seed treatment uses. Potential acute risks to passerine 

species is uncertain due to a lack of data. Also, potential risk from use of spent mushroom compost contaminated 

with thiabendazole is unknown. 

b

 Previous assessments have shown that risk from seed treatment uses are low; however, risk from mushroom uses 

are have not been assessed and potentially could be a concern. 

c

 Previous assessments did not assess risk to this taxa because of the lack of toxicity data; however, newly 

submitted toxicity data suggest that risks are low. 

Yes = at least one LOC has been exceeded in previous assessments or risks could not be assessed based on the 

available information; “No“ = LOCs have not been exceeded in previous assessments, or LOC exceedances are not 

expected. “?”= Risks are unknown until exposures from mushroom compost is assessed. 
7 

b. Drinking Water Assessments 

The most recent drinking water exposure assessment for the seed treatment use on field corn, 

sweet corn, and pop corn was conducted for thiabendazole in 2009 (USEPA, 20092

). The highest 

Tier 2 EDWCs for the surface water drinking water exposure concentrations for the proposed 

corn seed treatment for thiabendazole were 0.018, 0.0048, and 0.0034 μg/L, for the peak, annual 

mean, and overall mean concentrations, respectively. Earlier drinking water assessments for 

thiabendazole as a seed treatment was considered for dry peas (D315436), for Section 18 use 

(time limited tolerance petition) on Brussels sprout, cabbage, and cauliflower in California 

(D326593, D326597, D326600), Washington (D327512, D327516, D327517), and wheat 

(D245780). For the Thiabendazole Reregistration Eligibility Document (RED) (D245780), the 

Tier 1 GENEEC drinking water EDWCs were 2.4 μg/L and 1.55 μg/L for the peak and average 

56 day concentration, respectively, for the maximum wheat seed treatment (0.20 lb a.i./acre). 

Previously, drinking water exposure from the mushroom use was not considered because the 

mushrooms are grown indoors. The potential exposure to drinking water from disposal of spent 

mushroom compost (casing and compost materials) was not considered. 

c. Clean Water Act Programs 

Thiabendazole is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act3

. In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for thiabendazole4. More information on impaired water bodies 

and TMDLs can be found at the Agency’s website5

. The Agency invites submission of water 

quality data for this pesticide. To the extent possible, data should conform to the quality 

standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired 

Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and 

Management Process6 in order to ensure they can be used quantitatively or qualitatively in 

pesticide risk assessments. Aquatic benchmarks7

 have not been established for thiabendazole. 

Any data submitted or otherwise located as part of the registration review process may be used to 

update aquatic life benchmarks, if applicable. 

5. Environmental Fate and Transport 

Environmental fate studies show that thiabendazole is persistent and immobile (Table 3). It is 

stable to hydrolysis and soil photolysis and degrades slowly in aerobic (half-life ~ 700 days) and 

anaerobic soil environments. Aquatic photolysis, with a half life of 1.2 days in clear water, 

appears to be the only significant degradation pathway. Under anaerobic aquatic conditions 

thiabendazole showed no evidence of abiotic or biotic degradation but moved rapidly from the 

 

2

 Wolf, J.K. 2009. Drinking Water Assessment for Maxim® Quattro fungicide (EPA Reg. No. 100-RGLE)) a new fungicide for 

field corn, sweet corn, and pop corn. DP Barcode 363978, October 13, 2009. 3 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 4 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PESTICIDES 5 http://www.epa.gov/owow/tmdl/

6 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm 7 http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm
8 

water phase to the sediment phase. Thiabendazole binds tightly to soil due to its high soil/water 

partitioning coefficients (Kocs > 1,000 mL/goc), thus limiting the amount available for leaching 

into ground water and for solution phase runoff into surface water. With the high sorption 

capacity, thiabendazole could be transported on eroded sediment. Terrestrial field dissipation 

studies showed thiabendazole to be extremely persistent with no observed leaching. Vapor 

pressure and Henry’s Constant indicate that thiabendazole poses a low concern for volatilization 

from soil and water. These studies are discussed in more detail in the ecological assessment in 

support of the RED (DP Barcode D245780). Pertinent physico-chemical and environmental fate 

and transport properties of thiabendazole are summarized in Table 3. 

Table 3. Chemical Properties and Environmental Fate Parameters of Thiabendazole 

Parameter Value Description Source 

(MRID #)

Selected Physical/Chemical Parameters 

Molecular mass 201.1 g/mol -- (Calculated) 

Molecular formula C10H7N3S -- 

Vapor pressure (25°C) 3.45 x 10-9 mm Hg 

4.0 x 10-9 mm Hg 

-- 48354601 

Thiabendazole 

RED (2002) 

Henry’s Law Constant (25°C) 3.26 x10-11 atm-m3/mol -- (Calculated) 

Dissociation Constants pKa1 = 4.5 

pKa2 = 12.01 

-- 48354604 

40947302 

Aqueous solubility Buffered solution (25C) at 

pH 5: 30 mg/L 

pH 7: 28 mg/L 

pH 9: 28 mg/L 

Water: 22.74 mg/L 

Buffer solution (20C) at: 

pH4: 79.82 mg/L 

pH7: 22.77 mg/L 

pH10: 23.75 mg/L 

-- 40947301 

48354601 

48354604 

Log octanol-to-water partition 

coefficient (log KOW) 

1.61 @ Room temperature = 16.6°C 48254601 

48354604 

Persistence

Hydrolysis half-life (22C) Stable @ pHs 5, 7, 9 Ratesa

 of transformation were 

extrapolated resulting in t1⁄2s (200 

days) far beyond the length of the 

study (30 days) 

41265301 

(D245780; 

02/04/99) 

Aqueous photolysis half-life (22.5 to 

23.2C) 

t1⁄2 = 1.2 days 96 hour study @ pH5 43328305 

Soil photolysis half-life (25C) Stable -- 41297301 

41397302 

Aerobic soil metabolism half-life 

(25°C) 

t1⁄2 = 688 days -- 41791201 

EFED 

Registration 

Document 

D245780 

Anaerobic soil metabolism half-life 

(25°C) 

t1⁄2 = 211 day Only degradate detected was 

benzimidazole in a 90 day study. 

(max 13.7 % AR;). 

41559601 
9 

Parameter Value Description Source 

(MRID #)

Anaerobic aquatic metabolism half-life No evidence of biotic or 

abiotic degradation. 

 Rapidly moved from water phase to 

the sediment phase. 

00122888 

00070753 

Aerobic aquatic metabolism half-life 

[dissipation half-life A] (25C) 

-- Study requirement waived 41559601 

(D169687; 

12/30/92) 

Mobility

Freundlich soil-water partition 

coefficients (KF); organic carbonnormalized Freundlich coefficients 

(KFOC) 

KF (mL/g)/ Koc(mL/goc): 

(soil textural class) 

2.49/1,104: (sand) 

15.97/3,992: (sandy loam) 

21.75/1,812: (silt loam) 

269.6/22,467: (clay) 

Mean = 7,343 mL/goc

Median = 2,902 mL/goc

41170102 

Field Dissipation

Terrestrial field dissipation half-life in 

upper 6 inch soil layer; (max. depth of 

observed leaching) 

t1⁄2 = 1100 days; (6 inches). 

t1⁄2 = 990 and 1444 days; (12 

inches) 

t1⁄2= 833 and 1093 days: (6 

inches). 

Winter wheat/loamy sand/WA 

Soybean and bare ground/sandy 

loam/IL 

Soybean and bare ground/sandy 

loam/GA 

43187201 

43187202 

43187201 

Octanol/Water Partition Coefficient 

(logPow) 

 1.61 -- 48354604 

Fish Bioconcentration

Fish bioconcentration factors (steadystate); depuration rate 86.5 (whole); 19.7 (edible), 

747 (viscera), 3-day 

depuration: 96% in viscera 

and 50% in edible tissue. 

Low bioconcentration potential in 

edible tissue, some potential to 

bioaccumulate in viscera but with 

rapid depuration 

41631801 

42022701 

a

 Transformation rates of thiobendazole: pH 5 (-0.0019 days-1); pH 7 (-0.0035 days-1); pH 9 (-0.0026 days-1)

a. Transformation Products 

Three degradates were identified in the aqueous photolysis study (benzimidazole-2-carboxamide 

as a major degradate; benzimidazole and benzimidazole-2-carboxylic acid as minor degradates), 

two minor degradates were identified in the aerobic soil metabolism study (benzimidazole and 5-

hydroxythiabendazole), and one major degradate was identified in the anaerobic soil metabolism 

study (benzimidazole) (see below) ( 

Table 4). The common name, chemical names, CAS No., molecular formula and mass, chemical 

structure, and maximum and final percent of applied radioactivity (AR) of the major degradates 

are summarized in Table 5. The proposed degradation pathway in soil is given in Figure 2. The 

only degradate that was analyzed for in the terrestrial dissipation studies is benzimidazole. Test 

results showed that benzimidazole was not detected in any soil layers. No data were available for 

the other three degradates to verify their presence in the field. However, since they comprised a 

relatively small fraction (less than 10%) of the total applied radioactivity in the laboratory 

studies, EFED believes that their concentrations in the fields will also be negligible. 
10 

Table 4. Thiabendazole degradates identified in Environmental Fate Studies. 

Degradates Hydrolysis Photolysis 

(water) 

Photolysis 

(soil) 

Aerobic 

Soil 

Anaerobic 

Soil 

Terrestrial 

Field 

Benzimidazole X X Xa 

5-hydroxy 

thiabendazole X 

Benzimidazole-2-

carboxamide Xa

 

Benzimidazole-2-

carboxylic acid X 

Unidentified [14C] X X 

Unknown 1 X 14CO2 X a

 - major degradates (>10%) 
11 

Figure 2. Proposed degradation pathway of thiabendazole in soil. 
12 

 Table 5. Thiabendazole and Its Environmental Degradates 

Name 

Chemical Name CAS No. Formula Molecular Mass 

Chemical Structure Study Type Maximum (%AR

PARENT

Thiabendazole 2-(4-thiazolyl)-1H-benzimidazole

CAS No.: 148-79-8

Formula: C10H7N3S 

MW: 201.25 g/mol 

Aerobic Soil Metabolism Anaerobic Soil Metabolism 

-

a 

TRANSFORMATION PRODUCTS 

Thiabendazole-5-hydroxy 5-hydroxythiabendazole; 

2-(4-Thiazolyl)-5-benzimidazololCAS No.: 948-71-0 Formula: C10H7N3S 

MW: 217.25g/mol 

Aerobic Soil 

Metabolism 

-

Benzimidazole 1H-Benzimidazole 

CAS No.: 962-28-7 Formula: C7H6N2

MW: 118.05 g/mol 

Aq. Photolysis (minor) 

Aerobic Soil 

Metabolism 

Anaerobic Soil Metabolism Terrestrial Field Dissipation 

- 

2.2% 

13.7% 

- 
13 

Name 

Chemical Name CAS No. Formula Molecular Mass 

Chemical Structure Study Type Maximum (%AR

Benzimidazole carboxylic acid 

1H-Benzimidazole-2-carboxylic acid CAS No.: Formula: C8H6N2O2

MW: 162.15 g/mol Aq. Photolysis (minor) - 

Benzimidazole-2-carboxamide 

1H-Benzimidazole-2-carboxamide CAS NO. 5805-52-7 Formula: C8H7N3O MW: 161.16 g/mol 

Aq. Photolysis (major) - 

a Increasing with time. 
14 

6. Receptors 

a. Effects to Aquatic Organisms 

Table 6 provides a summary of toxicity endpoints that characterize the acute and chronic 

toxicity of thiabendazole to aquatic organisms. Based on the available ecotoxicity data, 

thiabendazole is classified as highly toxic to fish and aquatic invertebrates on an acute 

basis. Chronic toxicity testing is available with freshwater fish and invertebrates. Chronic 

toxic effects were observed in the rainbow trout at concentrations as low as 0.23 mg 

a.i./L, with a NOAEC established at 0.11 mg a.i./L. Chronic toxic effects were observed 

in the water flea at concentrations as low as 0.087 mg a.i./L, with a NOAEC established 

at 0.042 mg a.i./L. 

No data are available on the chronic toxicity of thiabendazole to saltwater fish or 

invertebrates. Chronic toxicity to saltwater invertebrates therefore will be estimated based 

on the acute-to-chronic ratio (ACR) for freshwater species (the water flea) and the acute 

toxicity value for the mysid. The ACR (EC50/NOAEC) for freshwater invertebrates is 

7.38. The chronic toxicity for saltwater invertebrates is estimated by dividing the acute 

EC50 for the mysid (0.34 mg a.i./L) divided by the ACR. This estimated chronic NOAEC 

value is 0.046 mg a.i./L. 

An aquatic plant toxicity test determined the EC50 for duckweed to be 0.56 mg a.i./L, 

indicating that vascular aquatic plants are also sensitive to thiabendazole. Limited data 

are available on the toxicity of thiabendazole to algae and cyanobacteria. 

Table 6. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for 

Thiabendazole. 

Taxonomic 

Group 

Study 

Type Surrogate Species 

Toxicity Value 

(in terms of active 

ingredient) 

Acute 

Toxicity 

Classification 

Source (Study 

Classification) 

Freshwater fish1

Acute 

Rainbow Trout 

(Oncorhynchus 

mykiss) 

96-hr LC50 = 0.56 

mg/L Highly toxic 41025005 (Acceptable) 

Chronic 

(Early 

LifeStage) 

Rainbow Trout 

NOAEC = 0.11 

mg/L 

LOAEC = 0.23 

mg/L 

Endpoint: Reduced 

weight 

-- 42508901 

 (Acceptable) 

Freshwater 

invertebrates Acute Water Flea 

(Daphnia magna) 

48-hr EC50 = 0.31 

mg/L2 Highly toxic 00123326 

(Acceptable) 

Chronic Water Flea 

NOAEC = 0.042 

mg/L 

LOAEC = 0.087 

mg/L 

Endpoint: survival, 

offspring 

production 

-- 

00094645 

(Acceptable) 
15 

Taxonomic 

Group 

Study 

Type Surrogate Species 

Toxicity Value 

(in terms of active 

ingredient) 

Acute 

Toxicity 

Classification 

Source (Study 

Classification) 

Estuarine/marine 

fish Acute 

Sheepshead Minnow 

(Cyprinodon 

variegatus) 

LC50 > 10 mg/L3 Slightly toxic 41192003 

(Supplemental) 

Estuarine/marine 

invertebrates 

Acute 

Mysid 

(Americamysis 

bahia) 

96-hr LC50 = 0.34 

mg/L Highly toxic 41192002 (Acceptable) 

Eastern Oyster 

(Crassostrea 

virginica) 

IC50 > 0.26 mg/L 

(22% inhibition at 

0.26 mg/L) 

Endpoint: shell 

growth 

Not 

determined 

41192004 

(Supplemental) 

Aquatic plants 

and algae Vascular Duckweed 

(Lemna gibba) 

7-day EC50 = 2.32 

mg/L 

NOAEC = 0.26 

mg/L 

Not defined 48996308 

(Supplemental) 

Nonvascular 

Freshwater Green 

Algae 

(Pseudokirchneriella 

subcapitata) 

96-hr EC50 = 3.06 

mg/L 

NOAEC = 0.532 

mg/L 

Not defined 49146601 

(Supplemental) 

1 Freshwater fish may be surrogates for aquatic-phase amphibians. 2

 A second acute toxicity study with Daphnia magna determined the 48-hr EC50 of thiabendazole to be 0.85 mg a.i./L 

(MRID 41709401). EPA’s policy is to use the lowest valid toxicity endpoint for a species when more than one is 

available. 

3

 30% mortality was observed at 10 mg a.i./L, the highest test concentration. Therefore, 10 mg a.i./L will be used as a 

conservative estimate of the LC50 for conducting a preliminary risk assessment. 

b. Effects to Terrestrial Organisms 

Table 7 provides a summary of toxicity endpoints that characterize the acute and chronic 

toxicity of thiabendazole to terrestrial organisms. Based on the available ecotoxicity data, 

thiabendazole is classified as practically nontoxic to birds (Bobwhite quail and mallard) 

and mammals on an acute basis. A waiver was submitted for the conduct of an acute 

toxicity study on passerines; however, it was denied. Chronic toxicity testing is available 

with birds and mammals. In birds, no chronic toxic effects were observed in the bobwhite 

and the mallard when tested with dietary concentrations as high as 400 mg a.i./kg-diet. 

Therefore, the NOAEC was established at 400 mg a.i./kg for both species. For mammals, 

acute oral toxicity classifies thiabendazole as practically nontoxic on an acute basis. For 

chronic toxicity to mammals, a two-generation rat reproductive study established the 

NOAEL at 10 mg a.i./kg/day based on reduction in body weight gain and food 

consumption at the next higher concentration of 30 mg a.i./kg/day (MRID 43190301). 

This NOAEL is equivalent to a dietary concentration of approximately 600 mg a.i./kgfood. Previous ecological risk assessments used a higher NOAEC of 1800 mg ai/kg-diet, 

but that was based only on the lack of reproductive effects observed in this study. Other 

studies also have noted sublethal toxic effects at dietary exposures at or near 600 mg 

a.i./kg-diet, including liver hypertrophy (MRID 43593201) and histopathological changes 

in bone marrow, liver, and thyroid (MRID 42942802). In a developmental rat study, a 
16 

growth effect was also observed in developing young (decreased fetal body weight) at the 

slightly higher dietary concentration of 800 mg a.i./kg-diet (MRID 42942803). 

Phytotoxicity testing thiabendazole determined that the most sensitive species were 

ryegrass and cucumber. The IC25 was 0.23 lb a.i./A for effects on seedling emergence, 

and ≥0.23 lb/A for effects on vegetative vigor. The NOAEC was less than 0.23 lb a.i./A 

for both the seedling emergence and vegetative vigor studies. 

Table 7. Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for 

Thiabendazole 

Taxonomic 

Group 

Study Type Surrogate 

Species 

Toxicity Value 

(all units in terms 

of active 

ingredient) 

Acute 

Toxicity 

Classification 

Source 

Birds1

Acute 

Bobwhite quail 

(Colinus 

virginianus) 

LD50 > 2,250 mg 

a.i./kg-bw 

Practically 

non-toxic 

41025002 

(Acceptable) 

Passerine 

species No data available 

Sub-acute 

dietary 

Bobwhite quail 

and mallard 

(Anas 

platyrhynchos) 

LC50 > 5,620 mg 

a.i./kg-diet 

Practically 

nontoxic 

41025003 & 

41025004 

(Acceptable) 

Chronic Bobwhite quail 

and mallard 

NOAEC = 

400 mg a.i./kg-diet 

LOAEC > 

400 mg a.i./kg-diet 

-- 

00123327 & 

00123328 

(Acceptable) 

Mammals 

Acute Oral 

Laboratory rat 

(Rattus 

norvegicus) 

LD50 = 

5070 mg/kg-bw (M) 

4734 mg/kg-bw (F) 

Practically 

nontoxic 41258201 

Acute 

Inhalation Laboratory rat LC50 > 6.84 mg/L Toxicity 

Category III 00100706 

Chronic 

(2-generation 

reproduction) 

Laboratory rat 

NOAEL = 

 10 mg/kg/day 

LOAEL = 

 30 mg/kg/day 

Endpoint: reduced 

body weight gain 

and food 

consumption 

-- 43190301 

Terrestrial 

invertebrates 

Acute 

contact 

Honey bee 

(Apis 

mellifera) 

LD50 > 34 μg/bee 

(No toxic effects) 

Practically 

nontoxic 

48996305 

(Acceptable) 

Acute oral Honey bee LD50 > 4 μg/bee -- 48996305 
17 

Taxonomic 

Group 

Study Type Surrogate 

Species 

Toxicity Value 

(all units in terms 

of active 

ingredient) 

Acute 

Toxicity 

Classification 

Source 

Terrestrial 

plants 

Seedling 

Emergence 

Monocot – 

Ryegrass 

NOAEC < 0.23 lb/A 

EC25 > 0.023 lb/A 

Endpoint: shoot 

length -- 

48996306 

(Acceptable, 

except 

Supplemental 

for bean and 

soybean) Dicot* NOAEC = 0.23 lb/A 

EC25 > 0.23 lb/A 

Vegetative 

Vigor 

Monocot* NOAEC = 0.23 lb/A 

EC25 > 0.23 lb/A 

-- 48996307 

Dicot – (Acceptable) 

cucumber 

NOAEC < 0.23 lb/A 

EC25 ≥0.23 lb/A 

Endpoint: 

emergence and 

survival 

* Because no significant inhibition was observed in any test species, the most sensitive species was not 

determined in this study. 

c. Ecological Incidents 

The ecological incident information system (EIIS) is an OPP database that houses 

ecological incidents that have been reported to the Agency. When available, EIIS 

includes date and location of an incident, type and magnitude of effects observed in 

various species, use(s) of pesticides known or suspected of contributing to the incident, 

and results of any chemical residue analysis or other analyses conducted during incident 

investigation. EIIS incidents are categorized according to the certainty that the incident 

resulted from pesticide exposure. The Avian Monitoring System (AIMS) is a database 

administered by the American Bird Conservancy that contains publicly available data on 

reported avian incidents involving pesticides. Many of the incidents listed in this database 

are also in the EIIS. 

In a search conducted on November 19, 2013, EIIS returned two incidents involving 

thiabendazole. One incident (I015152-001) involved damage to a soybean crop in 2004 

as a result of an accidental misuse. In this incident, tebuconazole was accidently added to 

a lot of the fungicide Rival (which contained the fungicides quintozene, thiabendazole, 

and captan) by a formulator. In another incident that occurred in 2012 (I023976-001), 

several bee hives were affected. Thiabendazole was one of several pesticides applied near 

the incident (i.e., fludioxonil, azoxystrobin, clothianidin, metalaxyl, and thiamethoxam). 

This incident is classified as “unlikely” for thiabendazole since thiabendazole has low 

toxicity to bees, whereas several of the other pesticides associated with the incident are 

known to be toxic to bees. No incidents have been reported in EIIS for thiabendazole 

hypophosphite. 
18 

As of November, 2013, there were no avian incidents reported in AIMS and no 

aggregated ecological incidents involving thiabendazole reported by the registrant. 

7. Exposure Pathways of Concern 

Direct outdoor uses of thiabendazole are limited to seed treatments and preplant treatment 

of bulbs and tubers. Therefore, spray drift and atmospheric transport are not expected to 

be relevant routes of exposure to plants and animals. As thiabendazole is moderately 

soluble, residues potentially could wash off or dissolve from the surface of treated seeds, 

bulbs, and tuber during rain events or irrigation, and transport through runoff could 

contaminate surface water. This route of exposure is expected to be limited because the 

high potential for thiabendazole to bind to soil particles gives it very little mobility in 

soil. Sorbed thiabendazole would be transported on eroded soil. 

 

Residues of thiabendazole that dissolve in soil pore water potentially could leach and 

contaminate ground water. Contamination from leaching, however, is expected to be very 

limited because of the low mobility of thiabendazole. 

Since mushrooms are grown indoors, use of thiabendazole during the cultivation of 

mushrooms is not expected to result in any significant environmental exposure during 

cultivation. However, after the mushrooms have been harvested, disposal of 

thiabendazole-contaminated growth medium (casing or compost), or use of the growth 

medium for mulch or compost, could potentially contaminate surface water and 

groundwater. A preliminary evaluation indicate that this route could be significant since 

the use rate on mushroom compost is much greater than that associated with seed 

treatment uses, and the high persistence of thiabendazole makes it likely that residues will 

persist in spent mushroom compost when it is disposed of or applied to soil. These routes 

of exposure therefore will be evaluated when assessing ecological risks associated with 

use of thiabendazole on mushrooms. 

For tree-injection uses of thiabendazole hypophosphite, a limited amount of water 

contamination may occur from residues that leach out of shed leaves and fallen trunks 

and branches. This route of exposure is expected to be minor since release of residues 

through these routes would be slow, and because of the high cost and labor of tree 

injection, only a small fraction of trees in a watershed are expected to be treated with 

thiabendazole. 

For terrestrial wildlife, direct consumption of seeds by granivorous animals is a primary 

route of exposure. Animals may be exposed to treated seeds through feeding on shallowly 

sown seeds in fields and on spilt seeds. Puddles and pooling of water on fields planted 

with treated seeds, bulbs, or tubers may also result in exposure of wildlife through 

consumption of drinking water. EPA’s Screening Imbibition Model8

 (SIP) was used to 

 

8

 Further information on the SIP model is available at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm. 
19 

screen for the potential for risk from drinking water. This model indicated that exposure 

from drinking water is not a significant concern for mammals, but could potentially be a 

concern for birds due to the potential for chronic effects. Because thiabendazole is not 

applied as a spray for outdoor uses, inhalation is not expected to be a significant route of 

exposure. Because many treated seeds, bulbs, and tubers would be planted underground, 

exposure through dermal absorption is also not expected to be a significant exposure 

route. 

Since thiabendazole is a systemic fungicide and is stable (except for aquatic photolysis), 

seed treatment may result in some of the active ingredient being absorbed by the roots of 

growing crops and translocate into the tissue and nectar of the crops. Therefore, the 

potential exists for some exposure to wildlife that feed on the foliage of crops grown 

from treated seeds, and to pollinator insects and birds which may feed on nectar from 

flowers of treated crops. However, this route of exposure is expected to be minor 

compared to direct consumption of treated seeds. Therefore, risk from this exposure route 

is assumed to be negligible. 

For tree-injection uses of thiabendazole hypophosphite, the primary route of terrestrial 

exposure would be through consumption of edible parts of treated trees. Birds and 

mammals would be exposed primarily through consumption of fruit and seeds of treated 

trees. Terrestrial insects may also be exposed through consumption of leaves, wood, 

nectar, or pollen of treated trees. 

For the materials preservative uses, thiabendazole poses potential risks to organisms in 

the aquatic environment if material leaches from treated exterior surfaces and the active 

ingredient is transported to impounded water bodies (e.g., ponds, lakes) or flowing 

waterways (e.g., streams, rivers). Thiabendazole also may reach the aquatic environment 

via down-the-drain discharge from use on textiles. Aquatic organisms likely to be 

exposed include fish, invertebrates, and aquatic plants. For aquatic animals, the major 

route of exposure is considered to be uptake via the respiratory surface (gills) or the 

integument from surface water residues. For aquatic plants, the major route of exposure 

is considered to be uptake from surface water. 

Thiabendazole has a low log kow (1.61) and the low bioconcentration factors in fish (19.7 

to 747). Therefore, bioaccumulation and bioconcentration of residues in fish and 

terrestrial wildlife is not expected to be significant. 

8. Analysis Plan 

a. Stressors of Concern 

The stressor of ecological and drinking water concerns is only the parent compound, 

thiabendazole. Thiabendazole is stable in the environment, and therefore formation of 

degradation products will be very slow. In the field dissipation studies, no degradation 

products of thiabendazole were detected ( 
20 

Table 4). Therefore, exposure to degradation products is expected to be minimal. 

Thiabendazole hypophosphite salt completely dissociates in water. Therefore, 

thiabendazole is also the ecological stressor for tree injection uses of thiabendazole 

hypophosphite. 

b. Measures of Exposure 

i. Exposure Modeling 

Drinking Water and Aquatic Exposure Modeling 

EPA will prepare updated drinking water and ecological aquatic exposure assessments 

for thiabendazole using standard available models9

 to evaluate potential exposure to 

pesticides in surface water (PRZM and EXAMS) and groundwater (PRZM-GW) sources 

as described at http://www.epa.gov/pesticides/science/models_db.htm. 

To estimate exposure to thiabendazole in water, all exposure modeling will be made 

based on maximum application rates. 

Although a drinking water exposure assessment would not per se be conducted for the 

use of thiabendazole on mushrooms, drinking water and aquatic exposure will be 

considered for residues in spent mushroom compost used as a soil amendment. For the 

mushroom compost disposal, application rates will be estimated from compost 

concentrations and rate of applications of the compost as a soil amendment. The 

maximum application rate for thiabendazole will be used in the PRZM/EXAMS and 

PRZM-GW modeling. Previous drinking water assessments did not consider the 

mushroom uses of thiabendazole where residues may remain on casing and in spent 

compost material that is used as a soil amendment. For further information on these 

EFED models see, http://www.epa.gov/oppefed1/models/water/index.htm.

AD will also conduct an aquatic exposure assessment for textile leaching and for 

wastewater discharge during manufacturing processes using the down-the-drain module 

of the EFAST Model. This assessment was not included in previous assessments. 

For antimicrobial applications of paints/stains to exterior surfaces, estimated 

environmental concentrations (EECs) will be modeled to provide estimates of acute and 

chronic exposure in the aquatic environment. The EECs are determined for a 1-ha, 1-m 

deep farm pond, based on the amount of thiabendazole leached from treated surfaces and 

the number and size of treated structures per unit of area. For textile use, determination 

of surface water concentrations will be done using the down-the-drain module of the 

EFAST Model. 

 

9 PRZM and EXAMS are Tier I and II models used to estimate environmental exposure concentrations in 

surface water. A description of these models and the guidelines for selecting input parameters can be 

found at http://www.epa.gov/oppefed1/models/water/
21 

Terrestrial Exposure Modeling 

Exposure to terrestrial animals is estimated using the Terrestrial Residue Exposure (TREX) model. Exposure to terrestrial plants is estimated using the TerrPlant model. For 

terrestrial plants, exposure is based on the calculated maximum application rates with 

assumed exposure from runoff, but not spray drift. These models are described at 

http://www.epa.gov/pesticides/science/models_db.htm. 

For terrestrial animals exposed to treated seed, the maximum application rate will be used 

to estimate the LD50-per-square-foot risk index. In addition, risk quotients will be 

calculated based on dietary exposure for animals that feed directly on treated seeds. This 

exposure is calculated by multiplying the amount of a.i. expected to be on a treated seed 

by the number of seeds an animal would need to consume in one day to meet its daily 

average food intake. Finally, risk is further characterized by calculating the number of 

treated seeds animals need to consume to reach a dose equal to the acute LD50 and 

chronic NOAEL. 

ii. Available Monitoring Data 

EPA is aware of monitoring conducted by federal (e.g., USGS NAWQA) and states (e.g.,

CDPR monitoring database) agencies. Available monitoring data will be evaluated and 

considered in an assessment conducted for Registration Review. 

iii. Approach to Estimating Exposure from Non-Seed Treatment 

Uses 

Mushroom Use 

Thiabendazole may be applied to mushrooms at any time during cultivation from 

spawning through 12 hours prior to mushroom harvest. Since mushrooms are grown 

indoors with closed irrigation systems, no appreciable exposure to the outdoor 

environment is expected during the time of culture. However, after a cycle of mushroom 

harvest is complete, the spent mushroom compost (SMC) is commonly applied to the 

surface of soil as a mulch, or mixed into farm or garden soil as a soil amendment.10 

Residues of thiabendazole that accumulated during mushroom cultivation potentially 

could remain in the SMC and be released into the environment at this time. 

The crop cycle of mushrooms typically involves several cycles of harvesting mushrooms 

(i.e., mushroom breaks) which form from the same body of mycelium growing in 

mushroom compost and overlaying casing. The label allows up to 27.9 lb a.i./A of 

thiabendazole to be applied throughout this crop cycle. The estimated residues in the 

 

10 http://extension.oregonstate.edu/gardening/what-mushroom-compost
22 

SMC will be based on one application at 11.2 lb a.i./A, followed by three subsequent 

applications at 5.6 lb a.i./A each, with 6 days between each application, and the last 

application to the mushrooms made 12 hours prior to the final harvest. The application of 

the SMC as a soil amendment will be assumed to take place 7 days after harvest. The rate 

of dissipation of thiabendazole residues in SMC is unknown; based on available data 

from field dissipation studies, thiabendazole appears to dissipate very slowly in soil (half 

lives 833-1444 days, MRID 43187201 and 43187202). 

Based on information on use of SMC provided by the Oregon State University Extension 

Service11 and the American Mushroom Institute,12 it is estimated that 2 to 3 inches of 

SMC will be applied to soil. The depth of compost (with casing) in mushroom houses is 

estimated to be approximately half this depth. When conducting the exposure modeling 

for application to outdoor soil, it will be assumed that a square-foot of compost in a 

mushroom house would be spread over approximately 2 square feet of soil; therefore, the 

application rates will be multiplied by 0.5 to account for this factor. 

Several other factors potentially could affect the amount of thiabendazole that is released 

from SMC into the environment: 

 Pasteurization of SMC prior to collection and distribution could potentially break 

down thiabendazole residues or could retard degradation by reducing microbial 

degradation. 

 SMC removed from the mushroom house may be stored outdoors for several 

months (for logistic reasons, or to be “weathered”), and significant dissipation of 

thiabendazole residues could occur during this time. 

 The high temperature and high microbial activity which occur in compost piles 

may accelerate degradation. 

 The very high in organic matter content of SMC may increase the binding 

capacity of amended soils and could result in different environmental fate activity 

than is observed in laboratory studies using mineral soil types (Grogan and Jukes, 

2003). 

The EPA would welcome any information that could be provided to better understand the 

fate of thiabendazole residues in SMC and to reduce the uncertainties of our exposure 

assessment. 

Leachate from piles of SMC stored outside and exposed to precipitation can contaminate 

ground and surface water (Chorover et al., 2001). Leachate from piles of thiabendazoletreated SMC potentially could be a source of thiabendazole contamination to nearby 

aquatic habitats and drinking water sources. 

 

11 Oregon State University Extension Service, 2003. “What is Mushroom Compost” 

http://extension.oregonstate.edu/gardening/what-mushroom-compost

12 http://www.mushroomcompost.org/Corn.pdf
23 

Tree-Injection Use (Thiabendazole Hypophosphite) 

Thiabendazole hypophosphite is used in tree-injection products that are injected into the 

trunks or root flares of elms, oaks, sycamore, and London plane. Exposure for this use 

pattern stems from translocation of the fungicide into parts of treated trees that are used 

as food items for animals, such as fruits and nuts. Information on the translocation and 

partitioning of thiabendazole into specific tissues of the tree is not available. Since the 

fungicide products are injected into the xylem, it is expected to be transported up the 

sapwood and into the upper portions of the tree. Therefore, the EPA will assume that the 

thiabendazole injected into the tree will be distributed evenly throughout the foliage 

component of the tree. The typical foliage biomass of trees may be calculated using the 

equations presented in Ter-Mikaelian and Korzukhin (1997). The predicted foliar 

concentration will be used as the assume thiabendazole concentration in all parts of 

treated trees that terrestrial animals would likely consume (leaves, fruits, nuts, twigs, and 

buds). 

For aquatic exposure, a screening-level assessment will be done based on thiabendazole 

being released from fallen leaves. Trees that are treated with thiabendazole 

hypophosphite will assume to surround a standard one-acre pond. Standard tree densities 

will be used to estimate the maximum number of trees that could grow on the perimeter 

of the pond. For a conservative screening-level assumption, all of the thiabendazole 

hypophosphite injected into the trees will be assumed to be translocated into the leaves, 

and released into the pond water when the leaves fall and decay. This amount will be 

divided by the volume of water in the pond to derive a conservative aquatic EEC for this 

use. 

Materials Preservatives Use 

An aquatic plant and animal risk assessment will be conducted for the materials 

preservatives uses for textiles and paints/stains. Data will be needed to determine the 

amount of thiabendazole which will leach from textiles. Determination of surface water 

concentrations of thiabendazole will be done using the down-the-drain module of the 

EFAST Model for textile leaching and for the amount of thiabendazole in the wastewater 

effluent during the manufacturing process at the manufacturing plant. 
24 

c. Measures of Effect 

Toxicity data presented in Section 3 of this problem formulation are used to calculate risk 

quotients. Any additional information submitted by the registrant or found in the open 

literature prior to conduct of a risk assessment will also be considered. The open 

literature studies are identified using EPA’s ECOTOXicology database (ECOTOX) 

(USEPA, 2007), which employs a literature search engine for locating chemical toxicity 

data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data 

can also provide insight into the direct and indirect effects of pesticides on biotic 

communities from loss of species that are sensitive to the chemicals and from changes in 

structure and functional characteristics of the affected communities. 

d. Estimation of Risk 

The exposure and toxicity data are integrated in order to evaluate the potential risks of 

adverse ecological effects on non-target species. The risk quotient (RQ) method is used to 

compare exposure and toxicity values. EECs are divided by acute and chronic toxicity 

values. The resulting RQs are then compared to the Agency’s levels of concern (LOCs). 

Risk presumptions, along with the corresponding RQs and LOCs for terrestrial animals 

are summarized in Table 8. 

 
25 

Table 8. Risk Presumptions and Levels of Concern 

Risk Presumption RQ LOC 

Birds1

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5 

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day 0.2 

Acute Endangered Species EEC/LC50 or LD50/sqft or LD50/day 0.1 

Chronic Risk EEC/NOEC 1 

Mammals1

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5 

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day 0.2 

Acute Endangered Species EEC/LC50 or LD50/sqft or LD50/day 0.1 

Chronic Risk EEC/NOEC 1 

1

 LD50/sqft = (mg/sq ft) / (LD50 * wt. of animal) 

 LD50/day = (mg of toxicant consumed/day) / (LD50 * wt. of animal) 

e. Endangered Species Assessments 

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), 

the Agency will evaluate risks to federally listed threatened and/or endangered (listed) 

species from registered uses of pesticides in registration review. The process for 

evaluating potential risks to listed species is further described at: 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm. 

f. Endocrine Disruptor Screening Program 

Thiabendazole was not included in the first group of 67 chemicals issued an order to 

conduct Tier 1 EDSP testing, or in the revised second list of 134 chemicals issued June 

14, 2013. For additional information the EDSP program, visit 

http://www.epa.gov/endo/. 
26 

9. Preliminary Identification of Data Gaps 

a. Environmental Fate

Table 9 identifies environmental fate studies for thiabendazole by MRID that offer data 

for each guideline requirement, as well as study classifications and whether or not further 

data are needed in order to support risk assessment. 

Upon review of the data available it appears that several studies are either not submitted 

or previously waived by the Agency. The Environmental Chemistry Methods (ECM) and 

Independent Laboratory Validation (ILV) have been submitted for soils, but not for 

water. The aerobic aquatic metabolism (OCSPP 835.4300; old Guideline 162-4) 

guideline study was previously waived (D16987, 12/30/1992) following the conventions 

at that time because there were no direct aquatic uses. Although the estimated 

environmental concentrations are expected to be low (based solely on the low proposed 

application rate), there would be uncertainty related to risks, most notably for aquatic 

organisms. This data would be useful if drinking water or aquatic exposure 

concentrations require refinements. Additional issues are noted in Table 9. 

Additional information concerning the fate of the spent mushroom casing and compost 

such as residue concentrations, amounts produced, rates applied as a soil amendment 

would be useful. Based upon the data available thiabendazole will be persistent but not 

very mobile in the environment. Thiabendazole is resistant to degradation by microbial 

metabolism as indicated by the slow degradation rates (i.e., long half-lives). It appears 

that the standard practice prior to disposing of the spent mushroom compost it to sterilize 

(or pasteurize) via heating. Therefore, an understanding of the degradation/metabolism 

rates, identification of degradation products, and sorption/desorption in spent mushroom 

compost before and after pasteurization is needed to understand the potential exposure 

from this use of thiabendazole. 

The existing fate and transport data adequately addresses most of the AD uses for 

thiabendazole. However, a number of AD use scenarios will trigger Down-the Drain 

estimation. In addition, for use of thiabendazole in natural and synthetic fibers, a leaching 

study is needed to estimate the exposure concerns due to the likely presence of 

thiabendazole in waste water stream effluents from manufacturing plants. A nonguideline leaching study will be needed for the treated fibers use. 

Table 9. Submitted Environmental Fate Data for Thiabendazole and Data Gaps 

OCSPP 

GUIDELINE MRID STUDY TITLE ISSUES 

Are 

Additional 

Data 

Needed? 

835.1230 41170102 Adsorption/desorption 

Data/Leaching - N 

835.2120 41265301 Hydrolysis - N 

835.2240 43328305 Photodegradation in water - N 
27 

OCSPP 

GUIDELINE MRID STUDY TITLE ISSUES 

Are 

Additional 

Data 

Needed? 

835.2410 41397301 

41397302 Photodegradation in Soil - N 

835.3110 

835.3220 

835.3280 

835.3240 

- 

Ready biodegradability test 

or one of three 

biodegradation in activated 

sludge simulation tests 

Transport to wastewater treatment 

plant and aquatic environment Y 

835.4100 41791201 Aerobic Soil Metabolism - N 

835.4200 41559601 Anaerobic Soil Metabolism - N 

835.4300 - Aerobic Aquatic 

Metabolism 

Requirement was waived because 

of no direct aquatic uses. N1 

835.4400 41559601 

Acc# 244423

Anaerobic Aquatic 

Metabolism waived2

 N 

835.6100 

43187201 

43187202 

43187203

Terrestrial Field 

Dissipation - N 

850.1730 41631801 Bioconcentration in fish - N 

850.6100 43187201 

43187203

Environmental Chemistry 

Methods (ECM) and 

Independent Laboratory 

Validation (ILV)

Soil 

Water (no study) 

N (soil) 

Y (water) 

Nonguideline 

study 

- Leaching from treated 

textiles 

Provide estimate of the total 

thiabendazole discharged into the 

wastewater through the 

manufacturing processes 

Y 

1

 While data are not being requested at this time, the lack of available aerobic aquatic metabolism data 

would preclude any refinements, if needed. 2

 Waived 162-3, 162-4, 164-2, 165-3(12/20/1992; D169687, D170813) 

b. Ecological Effects

Table 10 identifies submitted ecological effects studies for aquatic species, and the 

current status of those guideline requirements. 
28 

Table 11 does the same for terrestrial species. The following ecological effects data are 

needed for conventional uses ecological risk assessment: 

 A study of avian acute oral toxicity (GLN 850.2100) with a passerine bird. 

 Studies algal toxicity (GLN 850.4500) with a freshwater and a saltwater diatom 

specie. 

 Studies algal toxicity (GLN 850.4550) with cyanobacteria (blue-green algae). 

 

The following ecotoxicity data are needed to support the antimicrobial uses ecological 

risk assessment: 

 An Activated Sludge Respiration Inhibition test (GLN 850.3300). 

. 

Table 10. Submitted Aquatic Ecological Effects Data for Thiabendazole

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Test Species Study 

Classifications

Are data 

needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

850.1010 Freshwater 

invertebrate 

acute toxicity 

41709401 Water flea Acceptable No -- 

00123326 Water flea Acceptable 

850.1035 

850.1045 

Saltwater 

crustacean 

acute toxicity 

41192002 Mysid Acceptable No -- 

850.1025 

850.1055 

Saltwater 

bivalve 

acute toxicity 

41192003 Eastern oyster Supplemental No 

 850.1075 Freshwater fish 

acute toxicity 

42477701 Bluegill 

sunfish 

Acceptable No -- 

41025005 Rainbow trout Acceptable 

41025006 Bluegill 

sunfish 

Supplemental 

00123311 Rainbow trout Acceptable 

00122906 Bluegill 

sunfish 

Acceptable 

 850.1075 Saltwater fish 

acute toxicity 

41192003 Sheepshead 

minnow 

Supplemental No 

 850.1300 Freshwater 

invertebrate 

life cycle 

00094645 Water flea Acceptable No -- 
29 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Test Species Study 

Classifications

Are data 

needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

 850.1350 Saltwater 

invertebrates 

life cycle 

(None) (N/A) (N/A) No EPA will estimate the 

NOAEC using the 

acute-to-chronic ratio 

method, based on the 

available acute toxicity 

data for the mysid and 

acute and chronic 

toxicity data for the 

water flea. Comparison 

of the acute mysid 

endpoint (0.34 mg 

a.i./L) with the acute 

daphnid endpoint (0.31 

mg a.i./L) indicates that 

these species have 

similar sensitivity to 

thiabendazole. 

Therefore, one would 

expect that the chronic 

toxicity value for the 

mysid also would be 

similar to that for the 

daphnid, and therefore 

obtaining a chronic 

toxicity value for the 

mysid is not expected to 

change the risk 

assessment conclusions 

for potential chronic 

risk to aquatic 

invertebrates. 

 850.1400 Freshwater fish 

early-life stage 

42508901 Fathead 

minnow 

Acceptable No -- 

00094644 Fathead 

minnow 

Acceptable for 

formulated 

product1 

00097969 Rainbow trout Acceptable for 

formulated 

product1 

 850.1400 Saltwater fish 

early-life stage 

(None) (N/A) No -- 

 850.1500 Fish life cycle (None) (N/A) No -- 

850.4400 Aquatic plant 

Toxicity Test 

using Lemna 

spp. 

48996308 Duckweed Supplemental No The supplemental study 

provides adequate 

information on toxicity 

to vascular aquatic 

plants for assessing 

ecological risk. 
30 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Test Species Study 

Classifications

Are data 

needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

850.4500 Algal toxicity 49146601 Supplemental Yes The supplemental study 

provides adequate 

information on the 

toxicity to green algae, 

but toxicity data are 

anticipated to be needed 

for freshwater and 

saltwater diatoms. 

850.4550 Cyanobacteria (None) Yes No toxicity data has 

been submitted to assess 

risk to cyanobacteria, 

and are anticipated to be 

needed. 

850.3300 ASRI (None) Yes No toxicity data has 

been submitted to assess 

risk to waste water 

treatment plant 

organisms. These data 

are anticipated to be 

needed. 

1. This study was conducted with the formulated product Mertect® 340-F, which contains 42.28% 

thiabendazole. 

 
31 

Table 11. Submitted Terrestrial Ecological Effects Data for Thiabendazole

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Test Species Study 

Classifications 

Are data 

needed for 

risk 

assessment? 

Current Additional 

Data Need 

 850.2100 Avian oral 

toxicity 

41025002 Bobwhite Acceptable Yes To better assess the 

risk of thiabendazole 

to all species of birds, 

including passerines, 

an acute oral toxicity 

study with a passerine 

species is anticipated 

to be needed. 

00123313 Bobwhite Acceptable 

00137948 Mallard Acceptable 

 850.2200 Avian dietary 

toxicity 

41025003 Bobwhite Acceptable No -- 

41025004 Mallard Acceptable 

00123314 Bobwhite Acceptable 

 850.2300 Avian 

reproduction 

00123327 Bobwhite Acceptable No -- 

00123328 Mallard Acceptable 

Nonguideline Avian 

inhalation 

(None) (N/A) 

 850.3020 Honey bee 

acute contact 

toxicity 

48996305 Honey bee Acceptable No -- 

850.3030 Honey bee 

residue on 

foliage 

(None) (N/A) No -- 

 850.3040 Field testing 

for pollinators 

(None) (N/A) No -- 

850.4100 Seedling 

Emergence 

and Seedling 

Growth 

48996306 10 species Supplemental 

for common 

bean and 

soybean, 

Acceptable for 

other 8 species 

No Data for common 

bean and soybean are 

supplemental, but are 

nevertheless adequate 

to show low risk for 

the current seed 

treatment uses. 

850.4150 Vegetative 

Vigor 

48996307 10 species Acceptable No -- 
32 

References 

Grogan, H M and A A Jukes. 2003. Persistence of the fungicides thiabendazole, 

carbendazim and prochloraz-Mn in mushroom casing soil. Pest Manage. Sci.

59:1225-1231. 

Guo, M, J Chorover, R Rosario, and R H Fox. 2001. Leachate chemistry of fieldweathered spent mushroom substrate. J. Environ. Qual. 30(5):1699-1709. 

Ter-Mikaelian, M. T. and M. D. Korzukhin. 1997. Biomass equations for sixty-five North 

American tree species. For. Ecol. and Manage. 97(1):1-24 

USEPA, 1999. EFED Reregistration Document for Thiabendazole. Environmental Fate 

and Effects Division, Office of Pesticide Programs, United States Environmental 

Protection Agency. Washington, DC. February 4, 1999. DP barcode: D245780. 

USEPA, 2006. Review of New Use for Thiabendazole (Mertect 340-F) as a seed 

treatment on dry peas. Environmental Fate and Effects Division, Office of 

Pesticide Programs, United States Environmental Protection Agency. 

Washington, DC. April 13, 2006; DP barcodes: D315436, D322581. 

USEPA, 2007. ECOTOX user guide: ECOTOXicology database system, v. 4.0. 

Washington, DC: US Environmental Protection Agency. Available at: 

http:/www.epa.gov/ecotox/

USEPA, 2009. Drinking Water Assessment for Maxim® Quatro Fungicide (EPA Reg. 

No. 100-RGLE, a new fungicide for field corn, sweet corn, and popcorn. 

Environmental Fate and Effects Division, Office of Pesticide Programs, United 

States Environmental Protection Agency. Washington, DC. October 13, 209. DP 

barcode D363978. 

USEPA, 2010. Environmental Fate and Ecological Risk Assessment for the Proposed 

Section 3 New Use of Thiabendazole on Field corn, Sweet corn, and Popcorn. 

Environmental Fate and Effects Division, Office of Pesticide Programs, United 

States Environmental Protection Agency. Washington, DC. January 6, 2010. DP 

barcode D363978. 

 
33 

Appendix A 

OPPIN Bibliography 

Ecotoxicity

060101 Thiabendazole Eco Effects Bibliography 03/13/12 

Note: Some MRIDs also show up for 060102 Thiabendazole hypophosphate 

71-1 Avian Single-Dose Oral Toxicity 

MRID Citation Reference 

123313 Fink, R.; Beavers, J.; Brown, R. (1977) Acute Oral LD50--Bobwhite 

Quail: Thiabendazole: Project No. 105-119. Final rept. (Unpublished 

study received Dec 5, 1977 under 618-88; prepared by Wildlife 

International Ltd. and Washington College, submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:232421-G) 

137948 Fink, R.; Beavers, J.; Brown, R. (1977) Acute Oral LD50--Mallard 

Duck: Thiabendazole: Project No. 105-118. Final report. (Unpublished 

study received Dec 5, 1977 under 618-88; prepared by Wildlife 

International Ltd. and Washington College, submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:232421-H) 

41025002 Grimes, J.; Jaber, M. (1989) Technical Thiabendazole: An Acute Oral 

Toxicity Study with the Bobwhite: Final Rpt. Proj. No. 105-138. 

Unpublished study prepared by Wildlife International Ltd. 26 p. 

92183004 Wislocki, P. (1990) Merck & Co. Inc. Phase 3 Summary of MRID 

41025002. Technical Thiabendazole: An Acute Oral Toxicity Study 

with the Bobwhite: Project No. 105-138. Prepared by WILDLIFE 

INTERNATIONAL. 9 p. 

122900 Fink, R.; Beavers, J.; Brown, R. (1978) Acute Oral LD50--Mallard 

Duck: Mertect LSP: Project No. 105-126. Final rpt. (Unpublished study 

received May 24, 1978 under 618-84; prepared by Wildlife 

International Ltd. and Washington College, submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:234030-A) 

122901 Fink, R.; Beavers, J.; Brown, R. (1978) Acute Oral LD50--Bobwhite 

Quail: Mertect LSP: Project No. 105-125. Final rpt. (Unpublished study 

received May 24, 1978 under 618-84; prepared by Wildlife 

International Ltd. and Washington College, submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:234030-B) 

 71-2 Avian Dietary Toxicity 

MRID Citation Reference 
34 

47899 or 

117805 

Knott, W.B.; Johnston, C.D. (1968) Thiabendazole: Safety Evaluation 

on Bobwhite Quail. (Unpublished study received Aug 7, 1974 under 

5F1537; prepared by Woodard Research Corp., submitted by Merck & 

Co., Inc., Rahway, N.J.; CDL:094556-G) CDL:091522-F) 

47900 or 

107425 or 

122827 

Fink, R. (1973) Final Report: Eight-Day Dietary LC50--Mallard Ducks: 

Project No. 105-101. (Unpublished study received Aug 7, 1974 under 

5F1537; prepared by Truslow Farms, Inc., submitted by Merck & Co., 

Inc., Rahway, N.J.; CDL:094556-H) 

122902 Fink, R.; Beavers, J.; Brown, R. (1978) - Eight day Dietary LC50-- 

Bobwhite Quail: Mertect LSP: Project No. 105-123. Final rpt. 

(Unpublished study received May 24, 1978 under 618-84; prepared by 

Wildlife International Ltd. and Washington College, submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:234030-C) 

122903 Fink, R.; Beavers, J.; Brown, R. (1978) Eight-day Dietary LC50-- 

Mallard Duck: Mertect LSP: Project No. 105-124. Final rpt. 

(Unpublished study received May 24, 1978 under 618-84; prepared by 

Wildlife International Ltd. and Washington College, submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:234030-D) 

123314 Fink, R.; Beavers, J.; Brown, R. (1977) Eight-day Dietary LC50-- 

Bobwhite Quail: Thiabendazole: Project No. 105-117. Final rpt. 

(Unpublished study received Dec 5, 1977 under 618-88; prepared by 

Wildlife International Ltd. and Washington College, submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:232421-I) 

41025003 Grimes, J.; Jaber, M. (1989) Technical Thiabendazole: A Dietary LC50 

Study with the Bobwhite: Proj. No. 105-136. Unpublished study 

prepared by Wildlife International Ltd. 29 p. 

41025004 Grimes, J.; Jaber, M. (1989) Technical Thiabendazole: A Dietary LC50 

Study with the Mallard: Proj. No. 105-137. Unpublished study prepared 

by Wildlife International Ltd. 28 p. 

92183005 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41025003. Technical Thiabendazole, A Dietary LC50 Study with the 

Bobwhite: Project No. 105-136. Prepared by WILDLIFE 

INTERNATIONAL. 9 p. 

92183006 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41025004. Technical Thiabendazole, A Dietary LC50 Study with the 

Mallard: Project No. 105-137. Prepared by WILDLIFE 

INTERNATIONAL. 9 p. 

71-4 Avian Reproduction 

MRID Citation Reference 

123327 

ACC 235974 

Fink, R.; Beavers, J.; Brown, R. (1978) One-generation Reproduction 

Study--Bobwhite Quail: Thiabendazole 98.5% Technical: Project No. 

105-120. Final rept. (Unpublished study received Nov 21, 1978 under 

618-75; prepared by Wildlife International Ltd. and Washington 

College, submitted by Merck & Co., Inc., Rahway, NJ; CDL:235974-A) 
35 

123328 Fink, R.; Beavers, J.; Brown, R. (1978) One-generation Reproduction 

Study--Mallard Duck: Thiabendazole 98.5% Technical: Project No. 

105-121. Final rept. (Unpublished study received Nov 21, 1978 under 

618-75; prepared by Wildlife International Ltd. and Washington 

College, submitted by Merck & Co., Inc., Rahway, NJ; CDL:235974-B) 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 

47897 Knott, W.B.; Johnston, C.D. (1968) Thiabendazole: Safety 

Evaluation on Bluegill Sunfish. (Unpublished study received Aug 7, 

1974 under 5F1537; prepared by Woodard Research Corp., 

submitted by Merck & Co., Inc., Rahway, N.J.; CDL:094556-E) 

117804 or 

123304? 

Knott, W.; Johnston, C. (1968) Thiabendazole: Safety Evaluation on 

Bluegill Sunfish. (Unpublished study received Apr 21, 1970 under 

0F0881; prepared by Woodard Research Corp., submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:091522-E) 

123304 

ACC 100340 

Knott, W.; Johnston, C. (1968) Thiabendazole Safety Evaluation on 

Bluegill Sunfish. (Unpublished study received Nov 27, 1968 under 

618-66; prepared by Woodard Research Corp., submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:100340-B) 

47898 

ACC 094556 

Knott, W.B.; Johnston, C.D. (1968) Thiabendazole: Safety 

Evaluation on Rainbow Trout. (Unpublished study received Aug 7, 

1974 under 5F1537; prepared by Woodard Research Corp., 

submitted by Merck & Co., Inc., Rahway, N.J.; CDL:094556-F) 

117803 Knott, W.; Johnston, C. (1968) Thiabendazole: Safety Evaluation on 

Rainbow Trout. (Unpublished study received Apr 21, 1970 under 

0F0881; prepared by Woodard Research Corp., submitted by Merck 

& Co., Inc., Rahway, NJ; CDL:091522-D) 

122905 Vilkas, A. (1977) The Acute Toxicity of Mertect LSP to the Rainbow 

Trout, Salmo gairdneri Richardson: UCES Proj. # 11506-42-05. 

(Unpublished study received May 24, 1978 under 618-84; prepared 

by Union Carbide Corp., submitted by Merck & Co., Inc., Rahway, 

NJ; CDL:234030-F) 

122906 Vilkas, A. (1977) The Acute Toxicity of Mertect LSP to the Bluegill 

Sunfish, Lepomis macrochirus Rafinesque: UCES Proj. #11506-42- 

04. (Unpublished study received May 24, 1978 under 618-84; 

prepared by Union Carbide Corp., submitted by Merck & Co., Inc., 

Rahway, NJ; CDL:234030-G) 

123311 or 

122822 in PC 

060102 

Knott, W.; Johnston, C. (1971) Metasol TK-100, 20% Solution and 2-

(4'Thiazolyl) Benzimidazole Safety Tests in Rainbow Trout. 

(Unpublished study received Dec 5, 1977 under 619-88; prepared by 

Woodard Research Corp., submitted by Merck & Co., Inc., Rahway, 

NJ; CDL:232418-D) 

126631 same 

as 123311 also 

in PC 060102 

Knott, W.; Johnson, C. (1971) Metasol TK-100, 20% Solution and 2-

(4'Thiazolyl)benzimidazole Safety Tests in Rainbow Trout. 

(Unpublished study received Mar 11, 1983 under 10445-31; pre- 
36 

pared by Woodard Research Corp., submitted by Calgon Corp., 

Pittsburgh, PA; CDL:249806-G) 

41025005 Beglinger, J.; O'Boyle, R. (1989) Acute Aquatic Effects of 

Thiabendazole on the Rainbow Trout, Salmo gairdneri: Study No. 

EN-412-GWN001-2. Unpublished study prepared by Eastman 

Kodak Co. 58 p. 

41025006 Beglinger, J.; O'Boyle, R. (1989) Acute Aquatic Effects of 

Thiabendazole on the Bluegill Sunfish, Lepomis macrochirus: Study 

No. EN-413-GWN001-2. Unpublished study prepared by Eastman 

Kodak Co. 55 p. 

42477701 Holmes, C.; Swigert, J.; Smith, G. (1992) Thiabendazole: A 90-hour 

Static Acute Toxicity Test with the Bluegill (Lepomis Macrochirus): 

Lab Project Number: 105A-118A. Unpublished study prepared by 

Wildlife Intl. Ltd. 42 p. 

92183007 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41025006. Acute Aquatic Effects of Thiabendazole (Sponsor 

Product No. 47982) on the Bluegill Sunfish (Lepomis macrochirus): 

Study No. EN-413-GWN001-2. Prepared by EASTMAN KODAK, 

Health and Environmental Laboratories. 12 p. 

92183009 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41025005. Acute Aquatic Effects of Thiabendazole (Sponsor 

Product No. 47982) on the Rainbow Trout, Salmo gairdneri: Study 

No. EN-412-GWN001-2. Prepared by Eastman Kodak Co. Health 

and Environmental Lab. 9 p. 

72-2 Acute Toxicity to Freshwater Invertebrates 

MRID Citation Reference 

122904 Vilkas, A. (1978) The Acute Toxicity of Mertect LSP to the Water 

Flea--Daphnia magna Straus: UCES Project # 11506-42-06. 

(Unpublished study received May 24, 1978 under 618-84; 

prepared by Union Carbide Corp., submitted by Merck & Co., Inc., 

Rahway, NJ; CDL:234030-E) 

123326 Vilkas, A. (1977) The Acute Toxicity of Thiabendazole Technical 

to the Water Flea (Daphnia magna Straus): UCES Proj. # 11506-

42- 02. (Unpublished study received Jul 5, 1978 under 618-75; 

prepared by Union Carbide Corp., submitted by Merck & Co., Inc., 

Rahway, NJ; CDL:235634-D) 

41709401 Holmes, C.; Bellantoni, D.; Peters, G. (1990) Thiabendazole: A 

48-Hour Flow-through Acute Toxicity Test with Cladoceran 

(Daphnia magna): Final Report: Lab Project Number: 105A-101. 

Unpublished study prepared by Wildlife International Ltd. 129 p. 
37 

72-3 Acute Toxicity to Estuarine/Marine Organisms 

MRID Citation Reference 

41192002 Surprenant, D. (1989) Acute Toxicity of Thiabendazole to Mysid 

Shrimp (Mysidopsis bahia) Under Flow-through Conditions: SLS 

Study No. 359.0888.6105.515: Report No. 89/1/2955. Unpublished 

study prepared by Springborn Life Sciences, Inc. 45 p. 

41192003 Surprenant, D. (1989) Acute Toxicity of Thiabendazole to 

Sheepshead Minnow (Cyprinodon variegatus) under Flow-through 

Conditions: SLS Study No. 359.0888.6106.505: Report No. 89-3-

2957. Unpublished study prepared by Springborn Life Sciences, 

Inc. 40 p. 

41192004 Surprenant, D. (1989) Acute Toxicity of Thiabendazole to Eastern 

Oysters (Crassostrea virginica) Under Flow-Through Conditions: 

SLS Study No. 359.0888.6107.504: Report No. 89-5-2986. Unpublished study prepared by Springborn Life Sciences, Inc. 51 p. 

92183008 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41192003. Acute Toxicity of Thiabendazole to Sheepshead 

Minnow (Cyprinodon variegatus) under Flow-through Conditions: 

Study No. 359.0888. 6106.505. Prepared by EASTMAN KODAK, 

HEALTH AND ENVIRONMENTAL LABORATORIES. 12 p. 

92183010 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41192004. Acute Toxicity of Thiabendazole to Eastern Oysters 

(Crassostrea virginica) under Flow-through Conditions: Study 

#359-888.6107.504. Prepared by SPRINGBORN LIFE SCIENCES, 

INC. 12 p. 

92183011 Wislocki, P. (1990) Merck & Co. Inc.. Phase 3 Summary of MRID 

41192002. Acute Toxicity of Thiabendazole to Mysid Shrimp 

(Mysidopsis bahia) under Flow-through Conditions: Study No. 

359.0888.6105.515. Prepared by SPRINGBORN LIFE SCIENCES, 

INC. 12 p. 

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle 

Study 

MRID Citation Reference 

94644 LeBlanc, G.A.; Mastone, J.D.; Wilson, B.F. (1981) The Toxicity of 

Mertect Fungicide to Fathead Minnow (Pimephales promelas) 

Embryos and Larvae: Report #BW-81-5-890. (Unpublished study 

received Jan 19, 1982 under 618-75; prepared by EG & G 

Bionomics, submitted by Merck & Co., Inc., Rahway, N.J.; CDL: 

246711-A) 

94645 LeBlanc, G.A.; Mastone, J.D.; Suprenant, D.C.; et al. (1981) The 

Chronic Toxicity of Mertect Fungicide to the Water Flea (Daphnia 

magna): Report #BW-81-6-900. (Unpublished study received Jan 
38 

19, 1982 under 618-75; prepared by EG & G Bionomics, 

submitted by Merck & Co., Inc., Rahway, N.J.; CDL: 246711-B) 

97969 LeBlanc, G.A.; Mastone, J.D.; Wilson, B.F. (1982) The Toxicity of 

Mertect Fungicide to Rainbow Trout (Salmo gairdneri) Embryos 

and Larvae: Report #BW-82-1-1099. (Unpublished study received 

Mar 25, 1982 under 618-75; prepared by EG & G, Bionomics, 

sub- mitted by Merck & Co., Inc., Rahway, N.J.; CDL:247102-A) 

42508901 Holmes, C.; Swigert, J. (1992) Thiabendazole: An Early LifeStage Toxicity Test with the Fathead Minnow (Pimephales 

promelas): Lab Project Number: 105A-111. Unpublished study 

prepared by Wildlife International Ltd. 58 p. 

40789802 LeBlanc, G.; Mastone, J.; Surprenant, D. (1981) The Chronic 

Toxicity of Mertect Fungicide to the Water Flea (Daphnia 

magna): Supplement to MRID 94645: Project ID. BW-81-6-900. 

Unpublished study prepared by EG & G Bionomics. 6 p. 

171-4A2 Nature of the Residue in Plants 

MRID Citation Reference 

5001172 

Verma, R.K.; Vyas, S.C. (1976) Uptake, translocation and 

persistence of five systemic fungicides in gram seedlings. 

Pesticides 10(12):21-24. 

5002793 

Bolkan, H.A.; Milne, K.S. (1975) Systemic uptake of four 

fungicides by potato plants. Plant Disease Reporter 59(3):214-

218. 

Environmental Fate

060101 Thiabendazole Fate Chemistry Bibliography 

161-1 Hydrolysis 

MRID Citation Reference 

122852 Wolf, F. (1972) Letter sent to Buck dated Aug 29, 1972: TBZ 

sugar beets pesticide: Project No. 5734 0360. (Unpublished study 

received Jan 28, 1972 under 2F1237; submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:094101-D) 

123315 WARF Institute, Inc. (1976) Environmental Chemistry: Hydrolysis 

of Radiolabelled Thiabendazole in Aqueous Solutions. (Unpublished study received Aug 4, 1977 under 618-75; submitted by 

Merck & Co., Inc., Rahway, NJ; CDL:232424-C) 
39 

146781 Warf Institute, Inc. (1976) Environmental Chemistry Hydrolysis of 

Radiolabelled Thiabendazole in Aqueous Solutions: Report a. Unpublished report. 128 p. 

41265301 Kabler, K.; Dykes, J. (1989) Hydrolysis as a Function of pH at 25 

Degrees C of Carbon-14-Thiabendazole: ABC Final Report 

#37636. Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 309 p. 

92183026 Van den Heuvel, W. (1990) Merck & Co. Inc.. Phase 3 Summary 

of MRID 41265301. Hydrolysis a Function of pH at 25 [degrees] of 

[Carbon-14]- pH at 25 [degrees] of [Carbon-14]- Thiabendazole: 

Project 37636. Prepared by ANALYTICAL BIO-CHEMISTRY 

LABORATORIES INC. 10 p. 

161-2 Photodegradation -- Water 

MRID Citation Reference 

146780 Warf Institute, Inc. (1976) Environmental Chemistry 

Photochemical Degradation of Thiabendazole: Report b. 

Unpublished report. 74 p. 

123316 WARF Institute, Inc. (1976) Environmental Chemistry: 

Photochemical Degradation of Thiabendazole. (Unpublished 

study received Aug 4, 1977 under 618-75; submitted by Merck & 

Co., Inc., Rahway, NJ; CDL:232424-D) 

41258203 

See 41265101 

Kabler, K.; Dykes, J. (1989) Determination of the Photolysis Rate 

of [Carbon - 14]-Thiabendazole in pH 5 Buffered Solution at 25 

degree C: Project ID 37637. Unpublished study prepared by 

Analytical Bio-Chemistry Laboratories, Inc. 743 p. 

41265101 Kabler, K.; Dykes, J. (1989) Determination of the Photolysis Rate 

of (Carbon - 14)-Thiabendazole in pH 5 Buffered Solution at 25 

[Degree] C.: ABC Final Report #37637. Unpublished study 

prepared by Analytical Bio-Chemistry Laboratories, Inc. 576 p. 

43328305 Flynn, J. (1994) Determination of the Aqueous Photolysis Rate of 

(carbon 14)-Thiabendazole: Final Report: Lab Project Number: 

41285. Unpublished study prepared by ABC Labs, Inc. 82 p. 

92183027 Van den Heuvel, W. (1990) Merck & Co. Inc.. Phase 3 Summary 

of MRID 41265101. Determination of the Photolysis Rate of 

[Carbon-14]- Thiabendazole in pH 5 Buffered Solution at 25 

[degrees]: [Carbon-14]- Thiabendazole Project 37637. Prepared 

by ANALYTICAL BIO-CHEMISTRY LABORATORIES. 11 p. 

161-3 Photodegradation -- Soil 

MRID Citation Reference 

70750 Chib, J.S.; North, S.P.; Harrison, S.L. (1980) Chloramben (3-
40 

Amino- 2,5-dichlorobenzoic Acid) Hydrolytic Degradation 

Studies: Project No. 00010121/780A. (Unpublished study 

received Feb 18, 1981 under 264-138; submitted by Union 

Carbide Agricultural Products Co., Inc., Ambler, Pa.; 

CDL:244443-C) 

120017 Merck, Sharp & Dohme (1971) Results of Tests on the 

Amount of Residue Remaining; Including a Description of 

Analytical Methods: (Thiabendazole). (Compilation; 

unpublished study received Aug 13, 1972 under 2F1237; 

CDL:091094-A) 

123324 Schroeder, C. (1978) Photodegradation of Thiabendazole in 

Soil. (Unpublished study received Jul 5, 1978 under 618-75; 

prepared by WARF Institute, Inc., submitted by Merck & Co., 

Inc., Rahway, NJ; CDL:235632-B) 

41397301 Dykes, J.; Kabler, K. (1990) Determination of the Photolysis 

Rate of [Carbon 14]-Thiabendazole on the Surface of Soil: 

(Revised Final Report): Lab Project Number: 37638. 

Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 602 p. 

41397302 Dykes, J. (1990) Determination of the Photolysis Rate of 

[Carbon 14] Thiabendazole on the Surface of Soil 

Supplemental Data: Lab Project Number: 376381. 

Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 32 p. 

92183037 Van den Heuvel, W. (1990) Merck & Co. Inc.. Phase 3 

Summary of MRID 41397301 and Related MRIDs 41397302. 

Determination of the Photolysis Rate of [Carbon 14]-

Thiabendazole on the Surface of Soil: Project 37638. 

Prepared by Analytical Bio-Chemistry Laboratories, Inc. 11 p. 

162-1 Aerobic Soil Metabolism 

MRID Citation Reference 

123321 WARF Institute, Inc. (1976) Environmental Chemistry: 

Metabolic Fate of Radiolabelled Thiabendazole in Soil: (Soil 

Metabolism): Report d. (Unpublished study received Aug 4, 

1977 under 618-75; submitted by Merck & Co., Inc., 

Rahway, NJ; CDL:232423-A) 

146782 Warf Institute, Inc. (1976) Metabolic Fate of Radiolabelled 

Thia-endazole in Soil (Soil Metabolism): Report d. 

Unpublished report. 145 p. 

41791201 Daly, D.; Williams, M. (1991) Aerobic Soil Metabolism of 

[Carbon 14] Thiabendazole: Final Rept: Lab Project 

Number: 37639. Unpublished study prepared by Analytical 

Bio-Chemistry Laboratories, Inc. 1876 p. 

162-2 Anaerobic Soil Metabolism 
41 

MRID Citation Reference 

146782 Warf Institute, Inc. (1976) Metabolic Fate of Radiolabelled 

Thiabendazole in Soil (Soil Metabolism): Report d. 

Unpublished report. 145 p. 

41559601 Daly, D.; Williams, M. (1990) Anaerobic Soil Metabolism of 

[Carbon 14] Thiabendazole: ABC final Report 37640. 

Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 1062 p. 

162-3 Anaerobic Aquatic Metabolism 

MRID Citation Reference 

122888 Steele, J.; Lechnir, R. (1979) Environmental Chemistry: 

Thiabendazole--Anaerobic Aquatic Metabolism. Interim rept. C. 

(Unpublished study received Jul 31, 1979 under 618-75; 

prepared by Raltech Scientific Services, Inc., submitted by 

Merck & Co., Inc., Rahway, NJ; CDL:098855-A) 

ACC244423 Thiabendazole Anaerobic Aquatic Metabolism, report (final), 

Jan. 14, 1981, by Raltech Scientific Services for Merck and 

Co., Rathway, NJ, Accession No. 244423. 

163-1 Leaching , Adsorption/Desorption 

MRID Citation Reference 

70748 Chib, J.S.; North, S.P.; Harrison, S.L. (1980) Chloramben (3-

Amino- 2,5-dichlorobenzoic Acid) Adsorption and Desorption 

Studies: Project No. 10121/1080. (Unpublished study 

received Feb 18, 1981 under 264-138; prepared in 

cooperation with A & L Agric. Lab., Inc., submitted by Union 

Carbide Agricultural Products Co., Inc., Ambler, Pa.; 

CDL:244443-A) 

70749 Chib, J.S.; North, S.P.; Harrison, S.L. (1980) Chloramben 

(2,5-Di- chloro-3-aminobenzoic Acid) Leaching Studies: 

Project No. 00010121/780B. (Unpublished study received Feb 

18, 1981 un- der 264-138; prepared in cooperation with A & L 

Agricultural Laboratories, Inc., submitted by Union Carbide 

Agricultural Products Co., Inc., Ambler, Pa.; CDL:244443-B) 

117800 Lauber, J. (1970) Letter sent to B. Greenwald dated Jan 20, 

1970: Soil study with thiabendazole--review of Erwin and 

Borum study. (Unpublished study received Apr 21, 1970 

under 0F0881; sub- mitted by Merck & Co., Inc., Rahway, NJ; 

CDL:091522-A) 

120631 Aharonson, N.; Kafkafi, U. (1975) Adsorption, mobility, and 

per- sistence of thiabendazole and methyl 2-
42 

benzimidazolecarbamate in soils. J. Agric. Food Chem. 

23(4):720-724. (Also In unpub- lished submission received 

Sep 27, 1979 under 4581-340; sub- mitted by Agchem Div., 

Pennwalt Corp., Philadelphia, PA; CDL: 099006-L) 

121795 Erwin, D.; Borum, D. (1970) Persistence of Thiabendazole in 

Soil. (Unpublished study received 1970 under 0F0881; 

prepared by Univ. of California--Riverside, Dept. of Plant 

Pathology, submitted by Merck & Co., Inc., Rahway, NJ; 

CDL:093178-B) 

123300 Steele, J. (1979) Environmental Chemistry: Partition of Thiabendazole between Water and Soils. (Unpublished study 

received Jul 31, 1979 under 618-75; prepared by Raltech 

Scientific Services, Inc., submitted by Merck & Co., Inc., 

Rahway, NJ; CDL: 098856-A) 

Not Given Mobility of Thiabendazole Aerobically Aged in Soil and 

Photodegraded Thiabendazole Collin Schroeder and John 

Steele, WARF Institute, Inc . 

123317 WARF Institute, Inc. (1976) Environmental Chemistry: Soil 

Leaching Study: Column Method Radiolabelled 

Thiabendazole. (Unpublished study received Aug 4, 1977 

under 618-75; submitted by Merck & Co., Inc., Rahway, NJ; 

CDL:232424-E) 

146783 Warf Institute, Inc. (1976) Soil Leaching Study: Column 

Method Radiolabelled Thiabendazole: Report c. Unpublished 

report. 90 p. 

Not provided Thiabendazole Aerobically Aged in soil and Photodegraded 

Thiabendazole. 

123323 Schroeder, C. (1978) Soil Mobility of Thiabendazole 

Aerobically Aged in Soil and Photodegraded Thiabendazole. 

(Unpublished study received Jul 5, 1978 under 618-75; 

prepared by WARF Institute, Inc., submitted by Merck & Co., 

Inc., Rahway, NJ; CDL: 235632-A) 

41170102 Dykes, J. (1989) "Soil Adsorption/Desorption with 

Thiabendazole": Project ID: Final Report No. 37635. 

Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 339 p. 

92183038 Van den Heuvel, W. (1990) Merck & Co. Inc.. Phase 3 

Summary of MRID 41170102. Soil Adsorption/Desorption with 

Thiabendazole: Project 37635. Prepared by Analytical BioChemistry Labs. 12 p. 

164-1 Terrestrial Field Dissipation 

MRID Citation Reference 

98889 Chevron Chemical Company (1979) ?Residue Data from Soil 

in Which Potato Tubers Were Grown from Seed Pieces 
43 

Treated with Ortho- cide-mertect 10-0.5 Seed Protectant|. 

(Compilation; unpublished study received Sep 18, 1979 

under 239-2474; CDL:241044-A) 

123322 WARF Institute, Inc. (1976) Environmental Chemistry: Field 

Dissipation Studies: Thiabendazole: Report e. (Unpublished 

study received Aug 4, 1977 under 618-75; submitted by 

Merck & Co., Inc., Rahway, NJ; CDL:232423-B; 235632) 

Not provided Supplement to Thiabendazole Field Dissipation Studies 

Collin Schroeder and John Steele WARF Institute. Inc. 

43187201 Jacobson, B. (1994) Terrestrial Field Dissipation for 

Thiabendazole in Wheat: Lab Project Number: 618-360-

92530: 37853-3. Unpublished study prepared by Qualls 

Agricultural Labs. and ABC Labs., Inc. 178 p. 

43187202 Jacobson, B. (1994) Terrestrial Field Dissipation for 

Thiabendazole in Soybeans: Lab Project Number: 618-360-

92516: 38043. Unpublished study prepared by Agri-Growth 

Research, Inc. and ABC Labs., Inc. 187 p. 

43187203 Jacobson, B. (1994) Terrestrial Field Dissipation for 

Thiabendazole in Soybeans: Lab Project Number: 618-360-

92678: 38042. Unpublished study prepared by Research 

Options, Inc. and ABC Labs., Inc. 177 p. 

164-2 Aquatic Field Dissipation 

MRID Citation Reference 

122856 Interregional Research Project No. 4 (1974) Environmental 

Study on Thiabendazole|. (Unpublished study received 1974 

under 4E1478; CDL:095866-A) 

123301 Steele, J. (1979) Thiabendazole: Combined Field Dissipation 

and Water Dispersal from Rice Paddies. (Unpublished study 

received Jul 31, 1979 under 618-75; prepared by Raltech 

Scientific Services, Inc., submitted by Merck & Co., Inc., 

Rahway, NJ; CDL: 098857-A) 

164-5 Long-term Soil Dissipation 

MRID Citation Reference 

146784 Warf Institute, Inc. (1976) Field Dissipation Studies: 

Thiabendazole: Report e. Unpublished report. 337 p. 

146785 Steele, J.; Schroeder, C.; Morton, S. (1977) Supplement to 

Thiabendazole Field Dissipation Studies: Report e:Mertect 

340-F. Unpublished report prepared by Warf Institute, Inc. 

241 p. 
44 

165-4 Bioaccumulation in Fish 

MRID Citation Reference 

41631801 Hirsch, M. (1990) Bioconcentration of Thiabendazole(2-(4-

Thiozolyl) -1H-Benzimidazole) in Bluegill Sunfish, Lepomis 

macrochirus: Final Report: Lab Project Number: EN-456-

GWN004-1. Unpublished Study prepared by Eastman Kodak 

Co., Health and Envir. Laboratories. 235 p. 

42022701 Hirsch, M. (1991) Bioconcentration of Thiabendazole (2-(4-

thiazo- lyl)-1H-Benzimidazole) in Bluegill Sunfish, Lepomis 

macrochirus: Lab Project Number: GWN009: 90-0313. 

Unpublished study prepared by Eastman Kodak Co. 267 p. 

123320 WARF Institute, Inc. (1976) Environmental Chemistry: 

Accumulation and Dissipation of Thiabendazole in Catfish. 

(Unpublished study received Aug 4, 1977 under 618-75; 

submitted by Merck & Co., Inc., Rahway, NJ; CDL:232425-C) 

Non-Guideline Study 

MRID Citation Reference 

97322 

Hine, R.B.; Johnson, D.L.; Wenger, C.J. (1969) The 

persistency of two benzimidazole fungicides in soil and their 

fungistatic activity against phymatotrichum omnivorum. 

Phytopathology 59(Jun):798-801. (Also in unpublished 

submission received Dec 29, 1969 under 0F0936; submitted 

by E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.; 

CDL:093241-C) 

121796 

Lauber, J. (1970) Letter sent to B. Greenwald dated Jan 16, 

1970: Soil study with thiabendazole--review of articles by Hine 

et al. (Unpublished study received 1970 under 0F0881; 

submitted by Merck & Co., Inc., Rahway, NJ; CDL:093178-C) 

123319 

WARF Institute, Inc. (1974) Environmental Chemistry: Effect of 

Thiabendazole on Soil Microorganisms. (Unpublished study 

received Aug 4, 1977 under 618-75; submitted by Merck & 

Co., Inc., Rahway, NJ; CDL:232425-B) 

 
45 

Appendix B 

SIP Model Output 

 

Table 1. Inputs 

Parameter Value 

Chemical name Thiabendazole 

Solubility (in water at 25oC; mg/L) 50 

 

Mammalian LD50 (mg/kg-bw) 4734 

Mammalian test species laboratory rat 

Body weight (g) of "other" mammalian species 

 

Mammalian NOAEL (mg/kg-bw) 40 

Mammalian test species laboratory rat 

Body weight (g) of "other" mammalian species 

 

Avian LD50 (mg/kg-bw) 2250 

Avian test species northern bobwhite quail 

Body weight (g) of "other" avian species 

Mineau scaling factor 1.15 

 

Mallard NOAEC (mg/kg-diet) 400 

Bobwhite quail NOAEC (mg/kg-diet) 400 

NOAEC (mg/kg-diet) for other bird species 

Body weight (g) of other avian species 

NOAEC (mg/kg-diet) for 2nd other bird species 

Body weight (g) of 2nd other avian species 

 

 

Table 2. Mammalian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 8.6000 8.6000 

Adjusted toxicity value (mg/kg-bw) 3641.2061 30.7664 

Ratio of exposure to toxicity 0.0024 0.2795 

Conclusion* 

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

 
46 

 

Table 3. Avian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 40.5000 40.5000 

Adjusted toxicity value (mg/kg-bw) 1620.9664 19.8450 

Ratio of exposure to acute toxicity 0.0250 2.0408 

Conclusion* 

Drinking water exposure 

alone is NOT a potential 

concern for birds 

Exposure through drinking 

water alone is a potential 

concern for birds 

 

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, 

when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water 

may contribute to a total exposure that has potential for effects to non-target animals.