## R EGISTRATION 

## R EVIEW



## E COLOGICAL 

## R ISK 

## A SSESSMENT



## P ROBLEM 

## F ORMULATION FOR 

## :



## B ORIC 

## A CID 

## S ALTS

B(OH)3

P REPARED B Y :

Ron Dean, Biologist William P. Eckel, PhD, Senior Physical Scientist Environmental Risk Branch 2 Environmental Fate and Effects Division Office of Pesticide Programs

A PPROVED B Y :

Tom Bailey, Chief Environmental Risk Branch 2 Environmental Fate and Effects Division Office of Pesticide Programs

2

### T ABLE OF 

### C ONTENTS

S TRESSOR S OURCE AND D ISTRIBUTION ............................................................................ 4 I NTEGRATION OF A VAILABLE I NFORMATION ........................................................................ 4 E COLOGICAL E FFECTS ........................................................................................................ 5 Toxicity Studies .............................................................................................................. 5 Toxicity to Avian Species ........................................................................................... 6 Birds, Chronic......................................................................................................... 8 Toxicity to Mammalian Species ................................................................................. 8 Mammals, Acute and Chronic ................................................................................ 8 Toxicity to Benificial Insects ...................................................................................... 9 Toxicity to Aquatic Animals ..................................................................................... 10 Freshwater Fish, Acute ......................................................................................... 10 Freshwater Fish, Acute ......................................................................................... 10 Freshwater Invertebrates, Acute ........................................................................... 10 Freshwater Invertebrates, Chronic ........................................................................ 11 Estuarine and Marine Animals, Acute and Chronic ............................................. 11 Toxicity to Plants ...................................................................................................... 11 E XPOSURE C HARACTERISTICS ......................................................................................... 12 Persistence and Mobility ....................................................................................... 13 Major Degradation Pathways and Degradates ...................................................... 13 Routes of Dissipation ............................................................................................ 13 C HARACTERISTICS OF E COSYSTEMS P OTENTIALLY AT R ISK ........................................... 13 C ONCEPTUAL M ODEL ....................................................................................................... 14 A NALYSIS P LAN O PTIONS ................................................................................................. 17 A NTICIPATED D ATA N EEDS ........................................................................................... 17 L ITERATURE C ITED ........................................................................................................... 24 List of Impaired Waters ............................................................................................. 25 List of Approved TMDLs ............................................................................................ 29

3

### S TRESSOR 

### S OURCE AND 

### D ISTRIBUTION

Boric acid salts are register ed as acaricides, algicides, fungicides, herbicides and insecticides. Most of the regi stered products are for indoor use. The multiple indoor and outdoor use products consist of dusts, wetta ble powders, liquids, granules, pellets, impregnated material, soluble concentrates/solids, bait so lids and liquids and liquids ready-to-use.

The highest labeled rate for boric acid salts is for Redzone Bait granular formulation, where applications of 45 lbs formulated product per acre (2.25 lbs a.i./A) may be applied at seven day intervals up to nine times a year for the control of Fire Ants ( Solenopsis richteri ) and Red Imported Fire Ants ( Solenopsis invicta ) in pastures, commercial nurseries, sod farms, home lawns, golf cour ses and commercial and recreational turf. This product is a bait formulation of corn grit and attractant oil.

When dissolved in water, boric acid salts produce boric acid (H 3 BO 3 ) and sodium ions. Therefore, boric acid will be treated as th e chemical stressor for this assessment. The active moiety is boric acid salts, which cau ses insects’ water-repe llent outer protective layer (exoskeleton) to lose its effectiveness, causing death by loss of body fluids. It also disrupts the protective membrane of fungal mycelia, sporangia, and spores, breaking it down and exposing these tissues to the drying e ffect of the atmosphere. Boric acid salts are also registered for use as herbicides.

Boric acid salts include the following registered active ingredients.

PC Code CAS Registry No

. Chemical Name 011001 10043-35-3 Boric acid 011102 1303-96-4 Borax (B4Na2O7•10H2O) 011103 12280-03-4 Boron sodium oxide (B8Na2O13), tetrahydrate 011104 7775-19-1 Boric acid, sodium salt 011107 12008-41-2 Boron sodium oxide (B8Na2O13) 011110 12179-04-3 Boron sodium oxi deB4Na2O7), pentahydrate 011112 1330-43-4 Boron sodium oxide (B4Na2O7) 011111 11130-12-4 Sodium borate pentahydrate 011002 1303-86-2 Boric oxide



### I NTEGRATION OF 

### A VAILABLE 

### I NFORMATION

The most recent ecological assessment for bor ic acid salts was done 7/17/08 for Redzone Bait granular formulation, for aerial applica tions of 45 lbs formul ated product per acre (2.25 lbs a.i./A) applied at seven day intervals up to nine times a year for the control of Fire Ants ( Solenopsis richteri ) and Red Imported Fire Ants ( Solenopsis invicta ) in pastures, commercial nurseries, sod farms, home lawns, golf cour ses and commercial and

4recreational turf. This applic ation resulted in risk quotient s (RQ’s) above the Agency’s level of concern (LOC) for federa lly listed and non-listed mammals.

The 1993 RED decision concluded that the Agen cy’s “concerns regard ing risks to birds, fish and wildlife species are minimal. Bo ric acid’s limited out door use patterns, low toxicity, and natural presence in terrestrial and aquatic environments are mitigating factors for any potential risk to nontarget organisms.” Howe ver, the application rate and method of Redzone Bait was not considered in that decision.



### E COLOGICAL 

### E FFECTS



### Toxicity Studies

Acute and chronic toxicity da ta from studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential direct effects of boric acid salts to the aquatic and terrest rial receptors identified in this section. This includes toxicity data on the technical grade active i ngredient, degradates, and when available, formulated products (e.g. “Six -Pack” studies). The open lite rature studies are identified through EPA’s ECOTOX database ( http://cfpub.epa.gov/ecotox/ ), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The eval uation of both sources of data can also provide insight into the direct and indirect effects of boric acid salts on biotic communities from loss of species that are sensitive to the chemical and from changes in structure and functional characteristics of the affected communities.

Table 1 provides a summary of the taxonomic groups and the surrogate species tested to help understand potential acute ecological e ffects of pesticides to these non-target taxonomic groups. In addition, the table provides a preliminary overview of the potential acute toxicity of boric acid salts by pr oviding the acute toxici ty classifications.

Table 1 Test Species Evaluated for A ssessing Potential Ecological Effects of Associated Acute Toxi city Classification

Taxonomic Group Example(s) of Surrogate Species Acute Toxicity Classification Birds 1 Mallard ( Anas platyrhynchos ) Bobwhite ( Colinus virginianus ) Practically non-toxic

Mammals Laboratory rat ( Rattus norvegicus ) Moderately toxic Benificial Insects Honey bee ( Apis mellifera ) Practically non-toxic Freshwater fish 2 Bluegill sunfish ( Lepomis macrochirus ) Rainbow trout ( Onchorhynchus mykiss ) Practically non-toxic

Freshwater invertebrates Water flea ( Daphnia magna ) Practically non-toxic

Estuarine/marine fish Sheepshead minnow ( Cyprinodon variegatus ) No data

Estuarine/marine Mysid shrimp ( Americamysis bahia ) No data

5invertebrates Eastern oyster ( Crassostrea virginica ) Terrestrial plants 3 Monocots: corn ( Zea mays ) Dicots: soybean ( Glycine max ) No data

Aquatic plants and algae Vascular: Duckweed ( Lemna gibba ) Nonvascular: Green algae ( Selenastrum capricornutum ) No data

1 Birds represent surrogates for terrest rial-phase amphibians and reptiles.

2 Freshwater fish may be surroga tes for aquatic-phase amphibians.

3 Four species of two families of monocots, of which one is corn; six species of at least four dicot families, of which one is soybeans

. There are no submitted studies regarding the t oxicity of boric acid salts to terrestrial vascular or aquatic vascular and non-vascular pl ants. Boron is an essential element in the diet of animals, and the metabolism of plan ts. Non excessive xposures may therefore be beneficial in many cases, rather than adverse. While natural concen trations of boron are essential for normal plant growth, an excess of boron is toxic to plants (WHO 1998). In many areas, there are naturally high levels of boron in the soil and water that would outweigh any potential exposure from boric acid use as a pesticide. According to ATSDR, the average concentration of boron in U.S. soil is 26 to 33 mg/kg, and the average surface water concentrations are about 0.1 mg/L (ATSDR, Sept. 2007. Draft Toxicological Profile, for Boron).



### Toxicity to Avian Species

According to data submitted to OPP, boric acid salts are practically non-toxic to birds on an acute basis. Literature studies indicate that reproductive effects in birds may occur, but only at exposures of 250 ppm in the diet or higher. Effects on egg hatchability and spermatozoa production were also found.

Birds, Acute An acute oral toxicity study using the technical grade of th e active ingredient (TGAI) is required to establish the toxicity of boric acid to birds. The preferred test species is either mallard duck (a waterfowl) or bobwhite qua il (an upland gamebird). Boric Acid is considered practically nontoxi c to avian species on an acute oral basis with an LD 50 of >2150 mg ai/kg.

No acute toxicity data for passerine species are available. Although the submitted avian acute data suggest that boric ac id is practically non-toxic to the Bobwhite Quail, toxicity data for game birds may not reflect risks to pa sserine birds which have been identified to be more sensitive to pesticides in some cas es than the Bobwhite Quail. In addition, because there are bait formulations for boric acid that are made from corn grit and oil, birds may be attracted to this bait and cons ume large quantities of it. Therefore, additional data are needed to accurately asse ss risks to these species. Acceptable avian acute oral toxicity values for boric acid salts are summarized in Table 2

.

6Table 2. Avian Acute Oral Toxicity

Species LD 50 (mg ai/kg ) Toxicity Category MRID No. Study Classification

Mallard Duck > 2150 Practically nontoxic ACC254367 Acceptable

(No Mortalities Observed)

Birds, Subacute Two subacute dietary studies using the TGAI are required to establish the toxicity of boric acid to birds. The preferred test species are mallard duck and bobwhite quail. Boric acid salts exhibit a 5-Day LC 50 of > 2510 ppm ai. Ther efore it is considered practically nontoxic to avian sp ecies on a subacute dietary basis. Results of these tests are tabulated below in Table 3

. Table 3. Avian Subacute Dietary Toxicity

Species 5-Day LC 50 (ppm ai) Toxicity Category MRID No. Study Classification

Mallard Duck > 5620 Practically nontoxic ACC254367 Acceptable

(No Mortalities Observed)

Bobwhite Quail > 5620 Practically nontoxic ACC254367 Acceptable

(No Mortalities Observed)

Mallard Duck > 10000 Practically nontoxic Not Reported/ Noles / 1984 Acceptable

(No Mortalities Observed)

Bobwhite Quail > 10000 Practically nontoxic Not Reported/ Noles / 1987 Acceptable

(No Mortalities Observed)

Bobwhite Quail > 2510 Practically nontoxic Not Reported/ Noles/ 1992 Acceptable

(No Mortalities Observed)

7Birds, Chronic Avian reproduction studies usi ng the TGAI are required for boric acid salt because the birds may be subject to repeated or conti nuous exposure to boric acid salt due to its persistence, especially preceding or during the breeding season.

Currently no reproductive toxicity studies have been submitted to the Agency and no acceptable studies are available from the ECOTOX database.



### Toxicity to Mammalian Species

Clinical signs of acute toxi city observed following acute exposures include depression, ataxia and convulsions Toxicity values classifications for bo ric acid salts are summarized in Table 1

.

Mammals, Acute and Chronic Based on the results of acute exposure studies, bo ric acid salt is classified as moderately toxic, with an LD 50 in male rats of 4.5 g boric acid salts/kg (Weir and Fisher 1972). Clinical signs of toxicity observed followi ng acute exposures incl ude depression, ataxia and convulsions.

In a two generation reproduction study c onducted in mice, boric acid salt was administered throughout the study in the di et at levels of 0, 1000, 4500, or 9000 ppm (0, 150, 675, or 1350 mg/kg). The parental LOA EL was 4500 ppm based on decreases in organ weights in both sexes. The repr oductive LOAEL was al so 4500 ppm based on decreased fertility and decreased pup weight. At this dose, the average number of days between litters increased afte r the second litter a nd the number of dams producing litters decreased significantly. At the highest dos e tested, no litters were produced and the males in this group had a decrease in sperm concentration and motility when compared to controls. The NOAEL reported for this study was 1000 ppm for this study.

In a reproduction study conducted in Sprague Dawley rats, boric acid salt was administered in the feed at doses of 0, 65, 154, or 515 mg/kg/day for three generations. The systemic and reproductive NOAELs we re 154 mg/kg/day and the systemic and reproductive LOAELs were 515 mg/kg/day. At this dose level, there was a reported decrease in weight gain dur ing the pre-mating period in bo th sexes and food efficiency was lower in females. The testes in males were atrophied and there was a reported decrease in the number of corpora lutea in females at the highest dose tested.

Additionally, no litters were produced when high dose males were mated to high dose females. When high dose females were mate d to control males, there was a reported decrease in the number of litters and pup survival was adversel y affected. These toxicity values are reported below in Table 4.

8Table 4. Mammalian Toxicity

Species/ Study Duration % ai Test Type Toxicity Value Affected Endpoints MRID No/ Author / Year.

Rat/ Acute Exposure Tech. Acute Oral 450 mg boric acid salts/kg Mortality. 5584/Weir and Fisher 1972
Mouse/Chronic Exposure Tech. 2 Generational 150 mg/kg NOAEL Decreased parental organ weight, fertility, and decreased pup weight 5584

Rat/Chronic Exposure Tech. 3- Generational 154 mg/kg/day NOAEL Decrease in weight gain during the pre-mating period in both sexes and food efficiency was lower in females. 68882



### Toxicity to Benificial Insects Test results indicate that boric acid salt is relatively non-toxi c to bees on an acute contact basis. Results of this test are tabulated below in Table 5

. Table 5. Nontarget Benificial Insect Acute Contact Toxicity

Species LD50 (ug ai/bee) Toxicity Category MRID/ Document No. Study Classification

Honey Bee 362.58 Practically nontoxic 40269201 Acceptable

Although these results indi cate that boric acid salts are rela tively non-toxic to bees on an acute contact basis, boric acid is registered for use as an insecticide. Therefore, the Agency will consider risks to ot her terrestrial invertebrates.

9

### Toxicity to Aquatic Animals

Freshwater Fish, Acute Two freshwater fish toxicity st udies using the TGAI are required to establish the toxicity of boric acid salt to fish. Th e preferred test species are ra inbow trout (a coldwater fish) and bluegill sunfish (a warmwater fish). A definitive LC 50 endpoint value could not be determined. The highest concentration te sted on the Rainbow Trout, was 1100 ppm ai, and exhibited no mortalities. Boric acid sa lts are therefore considered practically nontoxic to freshwater fish on an acute basis. Results of these tests are tabulated below in Table 6

.

Table 6. Freshwater Fish Acute Toxicity

Species 96-hour LC50 (ppm ai) Toxicity Category MRID/ Document No. Study Classification

Bluegill sunfish > 1021 Practically nontoxic 40594602 Acceptable

Rainbow trout > 800 Practically nontoxic TN 2751

Doc. No.: 2047235/42 Supplemental

Rainbow trout > 1100 Practically nontoxic 40594601 Acceptable

Freshwater Fish, Chronic There are no acceptable studies by which to asse ss chronic fish toxicity for boric acid salts. It can be assumed that fish are adap ted to naturally-occurring boron levels in their local environments. Therefore, there is onl y a concern for water bodies with naturally low levels of boron because the fish inhabi ting these waters are not selected to be resistant to boron, nor would they be expected to be acclimated to high levels of boron.

Freshwater Invertebrates, Acute A freshwater aquatic invertebrate toxicity test using the TGAI is requ ired to establish the toxicity of boric acid salt to aquatic inve rtebrates. The preferred test species is Daphnia

magna . The most sensitive EC 50 endpoint, as exhibited by Daphnia magna, is 133 ppm ai, boric acid salt is considered practically nontoxic to aquatic invertebrates on an acute basis. Results of this test are tabulated below in Table 7

.

10Table 7. Freshwater Invertebrate Acute Toxicity

Species 48-hour EC50 (ppm ai) Toxicity Category MRID/ Document No. Study Classification

Water flea 133 Practically nontoxic Doc No.: 2024942 Acceptable

Water flea 226 Practically nontoxic Doc No.: 2024942 Supplemental

Water flea 777 Practically nontoxic TN 2750 Supplemental

Freshwater Invertebrates, Chronic There are no acceptable studies by which to assess chronic invertebrate toxicity for boric acid salts. However, it can be assumed that invertebrates are adapted to naturallyoccurring boron levels in thei r local environments. Theref ore, there is a concern for water bodies with naturally low levels of boron because the species inhabiting these waters are not selected to be resistant to boron, nor would they be expected to be acclimated to high levels of boron..

Estuarine and Marine Animals, Acute and Chronic There are no acceptable studies by which to assess acute or chronic toxicity of boric acid salts to estuarine or marine fish or inverteb rates. However, there is a high naturallyoccurring level of boron in seawater. It can be assumed that marine organisms are adapted to naturally-occurring bo ron levels. The contribution of pesticidal uses of boric acid is expected to be negligible.



### Toxicity to Plants

Terrestrial Plants There are no acceptable studies by which to asse ss the toxicity of boric acid salts to terrestrial plants. However, it is expected th at literature data will be available to assess both adverse and beneficial effects of boron on plants. It is generally known that terrestrial plants differ in th eir tolerance of, and requirement for, boron. In many cases, crops are studied for the e ffects of boron deficiency.

11Aquatic Plants There are no acceptable studies submitted to the agency by which to assess the toxicity of boric acid salts to aquatic vasc ular and non-vascular plants. There is a study in the open literature that suggests that Waterweed ( Elodea Canadensis ) and Watermillfoil ( Myriophyllum alterniflorum ) express an LD 50 of 5.0 ppm (WHO 1998). However, this study has not been reviewed by the agency. This and other relevant data will be considered during the risk assessment.



### Incident Reports

There are no reported incidents involving Bo ric Acid in EFED’s Ecological Incident Information System regarding boric acid salts. The absence of documented incidents does not necessarily mean that such incidents did not occur. Mortalit y incidents must be seen, reported, investigated, and submitted to the Agency in order to be recorded in the incident database. Incidents may not be noticed because the car casses decayed, were removed by scavengers, or were in out-of-the -way or hard-to-see locations. Due to the voluntary nature of incident reporting, an in cident may not be reported to appropriate authorities capable of investigating it.



### E XPOSURE 

### C HARACTERISTICS

All boric acid salts yield boric acid upon contac t with water. Therefore, boric acid will be treated as the chemical stressor for this assessment. Table 8 provides a list of boric acid’s chemical characteristics.

Table 8 Nature of the Chemical Stressor

Value Source Common name Boracic acid, ortho boric acid salts, borofax Chemical name Boric acid Pesticide type Inorganic salt Chemical class Merck Index, 1983

CAS number 10043-35-3 Empirical formula H 3 BO 3 Molecular mass (g/mol) 61.84 Vapor pressure Volatile with

steam Merck Index, 1983

Henry’s Law Constant (atmm 3 /mol) Not calculated

Solubility in water (g/L) 1 g/18 mL cold

water Merck Index, 1983

121 g/4 mL boiling water Log K ow Not applicable pK a (or pK b ) pH of 0.1 molar solution: 5.1 Merck Index, 1983



### Persistence and Mobility

Boron acid salts dissolve in water to produce boric acid (H 3 BO 3 ). Boric acid should persist indefinitely until absorbed and meta bolized by a plant or animal. As an acid, boric acid will be present in the water column, and will be very mobile.



### Major Degradation Pathways and Degradates

Boric acid is the stable form of boron in th e environment, and is not expected to break down any further. Boric acid may act as a Le wis base and complex w ith an electron pair donor.



### Routes of Dissipation Boric acid dissipates by transp ort in surface or ground water.

Clean Water Act:

Some areas, such as the western US, have higher natural borate content in soil, and therefore in adjacent waters. In such areas, it is expected that the plants and animals naturally present are adapted to, or tolerant of, higher borate levels, and that less-tolerant organisms will not be present, or will find such areas to be marginal habitat.

Certain water bodies have been identified under section 303(d) of the Clean Water Act by the USEPA Office of Water as requiring limits on borate co ncentration (Total Maximum Daily Load, TMDL). Use of Boric acid salts in these watersheds may be subject to regulation under the Clean Wate r Act (see Appendix C). An updated list of watersheds listed under section 303(d) will be obtained duri ng the Analysis phase of the registration review.



### C HARACTERISTICS OF 

### E COSYSTEMS 

### P OTENTIALLY AT 

### R ISK

EFED files indicate that boric acid products have similiar ch emical properties, use rates and patterns. Outdoor use pa tterns include: terrestrial f ood and feed crops, unspecified agricultural crops/soils , and orchards, terrestrial non-food crops, agricultural uncultivated areas, golf course turfs, air ports, landing fields, recreati onal areas, refuse solid waste sites, and rights-of-way, outdoor residental uses, ornament als lawns and turf, swimming pools, aquatic food crops, drainage ditchba nks, lakes/ponds/reservoirs, aquatic non-food industrial areas, sewage systems and drainage systems, forestry, and forest products (treated wood).

13

### A SSESSMENT 

### E NDPOINTS

Assessment endpoints are defined as “explicit expressions of the ac tual environmental value that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the envir onment that are considered to be at risk; and 2) operationally defining the assessment endpoint in terms of an ecolo gical entity (i.e., a community of fish and aquatic invertebrate s) and its attributes (i.e., survival and reproduction). Therefore, selection of th e assessment endpoints is based on valued entities (i.e., ecological recep tors), the ecosystems potential ly at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide-related contamination. The selecti on of clearly defined assessment endpoints is important because they provide direction a nd boundaries in the ri sk assessment for addressing risk management issues of c oncern. Changes to assessment endpoints are typically estimated from the available toxicity studies, which are used as the measures of effects to characterize potentia l ecological risks associated w ith exposure to a pesticide, such as boric acid salts.

To estimate exposure concentra tions, the ecological risk asse ssment considers application at the maximum rate to fields that have vul nerable soils. If multiple applications are allowed, the maximum amount per applic ation and minimum interval between applications are used – provided that maximu m total annual applic ation amounts are also included in this configuration. Several EFED exposure models (e.g., GENEEC, PRZMEXAMS, T-REX) are used to estimate likely high-end exposure to boric acid salts. The most sensitive toxicity endpoints are used from surrogate test species to estimate treatment-related direct eff ects on acute mortality and chr onic reproductive, growth and survival assessment endpoints. Toxicity te sts are intended to determine effects of pesticide exposure on birds, mammals, fish, te rrestrial and aquatic invertebrates, and plants. These tests include short-term acu te, sub-acute, and repr oduction studies and are typically arranged in a hierarchical or tiered system that progresse s from basic laboratory tests to applied field studies. The toxicity st udies are used to evaluate the potential of a pesticide to cause adverse effects, to determ ine whether further tes ting is required, and to determine the need for precautionary label st atements to minimize the potential adverse effects to non-target animals and plants.



### C ONCEPTUAL 

### M ODEL

In order for a chemical to pose an ecologica l risk, it must reach ecological receptors in biologically significant concen trations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an ecological receptor. For an ecological exposure pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecologi cal receptors, and a feasible route of exposure.

14The conceptual model (Figure 1) depicts the potential pathways for ecological risk associated with boric acid use. The con ceptual model provides an overview of the expected exposure routes for organisms within the boric acid action area. For terrestrial organisms, the major route of exposure (aside from direct contact to insects from foliar applications) considered here is ingestion of food items such as grasses, other green vegetation, seeds, and insects that harbor boric acid residues as a result of direct application or drift. For aquatic organisms, the major routes of exposure are considered to be via the respiratory surface (gills) or th e integument. Aquatic plants may be exposed via direct uptake and adsorption. Estimate d exposure concentrations for all organisms are obtained through the use of several Ag ency exposure models. Note that only aerial/ground spray and chemig ation applications are depicted here; hand spray (spot treatment) is expected to result in much less exposure.

Only outdoor use sites will be considered in this assessment. The use of borax products in non-pesticide products (for example, in la undry products) is expected to dominate the exposure from indoor use and “down-the-dr ain” exposure via sewage treatment and discharge.

15Figure 2. Ecological conceptual diagram for boric acid salts

R ISK H YPOTHESIS

Based on an examination of the physical/chemi cal properties of boric acid salts, the fate and disposition in the environment, and m ode of application, a conceptual model was developed that represents the possible rela tionships between the stressor, ecological receptors, and the assessment endpoints. Fo r boric acid salts, the following ecological risk hypothesis is being employed for this baseline risk assessment:

Boric acid salt, when used in accordance with its labels, results in potential adverse effects upon the su rvival, growth, and reproduction of non-target terrestrial and aquatic organisms. There are no data to assess the effects of boric acid exposure to passerine birds, estuarine/marine organisms or the chronic risks that boric acid may pose to aquatic invertebrates. There are also no acceptable data submitted to the Agency by which to evaluate risks boric acid salts may pose to terrestrial vascular or aquatic vascular and non-vascular plants. Due to the fact that the sensitivity to chemicals may vary gr eatly between groupings of taxa, and that the acute sensitivity of an or ganism may not accurately predict the chronic sensitivity, in most cases the Agency must make the assumption

16that there will be acute and chronic ri sks to species for which there are no data.



### A NALYSIS 

### P LAN 

### O PTIONS

In registration review, pesticide ecological risk assessments will follow the Agency’s Guidelines for Ecological Risk Assessment, will be in compliance with the paper titled “Overview of the Ecological Risk Assessm ent Process in the Office of Pesticide Programs, U.S. Environmental Protection Ag ency” (“Overview Document”) (January 2004), and will be done in accordance with Se ction 7 of the Endangered Species Act.

Results from aquatic and terres trial exposure models (GENEEC 2, T-Rex) will be used to determine likely high-end exposure conditions resulting from boric acid use (and compared with results from previous documents). It is likely that only Tier 1 aquaticmodeling (GENEEC2) will be used, since the applicability of the Tier 2 model (PRZMEXAMS) is questionable for an inorganic compound such as boric acid salts. These predicted exposure values will then be used to determine the possible environmental effects of boric acid use.

If the planned ecological risk assessment indi cates that boric acid exceeds the Agency’s Level of Concern for Listed species, either directly or indirectly, a preliminary “May Affect” determination will be made for the affected taxa (e.g., birds, mammals, fish, invertebrates, etc). A map of the boric acid use “footprint,” consis ting of all land cover types for which the LOC is exceeded ma y be generated, along with a narrative description of the area outside the footprint wh ere effects are expected to occur. These maps and narrative descriptions will be provi ded to the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (t he Services) for them to determine which listed species may be affected. The Agency w ill then consult with the Services, formally or informally, to refine the Effects Determination.

A NTICIPATED D ATA N EEDS

The Agency does foresee requiring additional ecological effects studies prior to conducting the planned assessments. Data gaps , uncertainties and potential paths forward for the assessment of boric acid are described below.

17Guideline Number: 850.2100 Study Title: Avian oral toxicity (Passerine species) Rationale for Requiring the Data
Because there are bait formulations for boric acid that are made from corn grit and oil, birds may be attracted to this bait and cons ume large quantities of it over an extended period of time. No data for passerine species are availabl e. Although the submitted avian acute data suggest that boric acid is practically non-toxic to the Bobwhite Quail, toxicity data for game birds may not reflect risks to passerine birds which have been identified to be more sensitive to pesticides in some cases than the Bobwhite Qua il. Therefore, additional data are needed to accurately assess risks to these spec ies. Specifically, data are required on one passerine species in addition to either one waterfowl species or one up land game bird species for terrestrial, aquatic, forestry, and residential outdoor uses. New CFR 158.630 guidelines now require that passerine species be tested for outdoor uses.

Practical Utility of the Data How will the data be used? The passerine acute toxicity data are needed fo r future regulatory deci sions, and for endangered species assessments. The data w ill allow the Agency to better asses s the risks to these organisms, including the likelihood of potential risks to enda ngered species, either by direct effects or by indirect effects such as reducing food sources to listed predators and scavengers. Results of this study would be used to calculate acute risks to passerine species from exposure to boric acid and to identify whether current labeling is appropriate and whether fu rther mitigation is necessary.

How could the data impact the Agency’s future decision-making? If the data indicate that boric acid poses a significan t acute risk to upland game or passerine birds, the Agency may explore additional decision options to minimize the risk of boric acid to these species. If future endangered species risk asse ssments are performed without these data, the Agency would have to assume that boric acid "m ay affect" passerine birds directly and other endangered species indirectly through loss of prey. The lack of these data will limit the flexibility the Agency and registrants have in complying w ith the Endangered Species Act and could result in unnecessary use restrictions, and the use of boric acid may need to be restricted in areas where endangered species occur unless these data are provided.

Guideline Number: 850.2300 Study Title: Avian reproductive toxicity Rationale for Requiring the Data Although the submitted avian acute data suggest that boric acid is practically non-toxic to the Bobwhite Quail, Adverse effects on avian reproduc tion can occur at levels of exposure several magnitudes lower than those that can cause acutely toxic effects. Boric acid is known to exert toxic effects on the male reproductive system, specifically causing testicular atrophy. Definitive data for this effect in avian species are needed to quan titatively assess this risk. A pesticide’s properties are not adequate predictors of avian reproduction e ffects. Because there are bait formulations that these species may consume over a long period of time, there is a need to determine the possible chronic risks this may pose to av ian species. Therefore, additional data are needed to accurately assess risks to these species. Specifically, data are required for terrestrial, aquatic, forestry, and residential outdoor uses.

18Practical Utility of the Data How will the data be used? The avian toxicity data are needed for future regulatory decisions, and for endangered species assessments. The data will a llow the Agency to better assess the risks to these organisms, including the likelihood of potential risks to enda ngered species, either by direct effects or by indirect effects such as reducing food sources to listed predators and scavengers. Results of this study would be used to calculate chronic risks to avian species from exposure to boric acid salts and to identify whether current labeling is appr opriate and whether further mitigation is necessary.

How could the data impact the Agency’s future decision-making? If the data indicate that boric acid salt poses a significant chronic risks to birds, the Agency may explore additional decision options to minimize the risk of boric acid salts to these species. If future endangered species risk assessments are performed without these data, the Agency would have to assume that boric acid salts "may affect " birds directly and other endangered species indirectly through loss of prey. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act a nd could result in unnecessary use restrictions, and the use of boric acid salts may need to be restricted in areas where endangered species occur unless these data are provided.

Guideline Number: 850.1400 Study Title: Fish Early-Life Stage Toxicity (freshwater) Rationale for Requiring the Data The requested data would allow EPA to refine its chronic risk (growth and reproduction) estimates for freshwater fish, and allow it to define an action area for endangered species. Risk mitigation strategies ( e.g. , determining maximum clethodim applica tion rate that results in an RQ below the LOC) cannot be evaluated without these data.

Since the registration of boric acid salts, the Agency has worked to finalize its update to the data requirements in 40 CFR Part 158. These updated da ta requirements were promulgated in October 2007. Now one freshwater fish early life stage study is required to support all terrestrial, aquatic, forestry, and residential turf use patterns.

40 CFR Part 158 was revised to list the fish early-life stage and aquatic invertebrate life-cycle studies as separate requirements in the data table; then identify each test organism as a freshwater or saltwater species. For the freshwater fish early-life stage and freshwater invertebrate life-cycle data requirements, the Agency requires testing of one fish species and one aquatic invertebrate species, respectively, for the terrestrial, aquatic , forestry, and residential turf use patterns. Previously, the freshwater invertebrate life cycle and freshwater fish early life stage tests were combined under one data requirement with testi ng required of only the more sensitive species in acute studies. However, when a pesticide enters the aquatic environment, both groups of organisms are exposed. Moreover, acute sensitivity is not a reliable indicator of chronic sensitivity, particularly when looking across different groups of organisms, so chronic data are needed regardless of the results of acute testing.

This change was warranted because the relative sensitivity of fish and invertebrates can vary widely across chemicals. Previously, only the more sensitive of the two organisms, either fish or aquatic invertebrates, as determined by Tier I acute studies, was tested. However, since both organisms are exposed when a pesticide enters an aquatic environment and the acute sensitivity of an invertebrate may not accurately predict the chronic sensitivity in fish and vice versa, both

19species must now be tested for chronic effects. The Agency cannot make the assumption that a chemical is not chronically toxic at much lo wer concentrations than some ratio of the LC 50 value would suggest. Practical Utility of the Data

How will the data be used? These data are needed for a registration re view decision and for an endangered species assessment, which will be conducted as part of that decision. The effects data would be used to determine the likelihood that the chronic risk s can potentially impact aquatic communities, by direct effects on fish and their reproduction. By refining the assessment, the Agency would be able to determine the appropriate mitigation for clethodim.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are performed without these data, the Agency would have to assume that clethodim “may aff ect” endangered fish directly (and endangered species from other taxa indirectly). Thus, use of clethodim might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for clethodim which are unnecessarily severe.

Guideline Number: 850.1300 Study Title: Daphnid chronic toxicity Rationale for Requiring the Data

Since the registration of boric acid salts, the Agency has worked to finalize its update to the data requirements in 40 CFR Part 158. These updated da ta requirements were promulgated in October 2007. Now one freshwater invertebrate life-cycle study is required to support all terrestrial use patterns.

The Agency had conditionally required fish early-life stage and aquatic invertebrate life-cycle studies (guidelines 850.1300, 850.1350, and 850.1400) for terrestrial food and nonfood, aquatic food and nonfood, forestry, and domestic outdoor uses. These studies still are not required for greenhouse food and nonfood, and indoor uses. The Ag ency has made several revisions to clarify the applicability of the requirements.

The first is to list the fish early-life stage and aquatic invertebrate life-cycle studies as separate requirements in the data table; then identify each test organism as a freshwater or saltwater species. For the freshwater fish early-life stage and invertebrate life-cycle studies, the Agency changed the conditional requirement for terrest rial and aquatic (food crop and nonfood) and forestry uses to required, and changed the a quatic nonfood residential use to not required. Previously, the freshwater invertebrate life cycle and fish early life stage tests were conditionally required for terrestrial, aquatic (food crop and nonf ood), and forestry uses. When promulgated in 1984, one basis for the conditional nature of the requirements was that only one of the two tests was required, depending on whether fish or invert ebrates were more sensitive in the acute studies. However, when a pesticide enters the aquatic environment, both groups of organisms are exposed. Moreover, acute sensitivity is not a reliabl e indicator of chronic sensitivity, particularly when looking across different groups of organisms, so chronic data are needed regardless of the results of acute testing. The change to ‘‘not re quired’’ for aquatic nonfood residential use is due to the fact that the previous ‘‘aquatic nonfood ’’ use pattern is now split into aquatic nonfood outdoor and aquatic nonfood reside ntial. As the latter represents a much smaller use pattern, the

20Agency has reduced or eliminated the data requi rement for aquatic nonfood residential uses. In addition, the Agency now requires both of these t ests for all turf uses including residential, since exposure varies.

This change was warranted because the relative sensitivity of fish and invertebrates can vary widely across chemicals. Previously, only the more sensitive of the two organisms, either fish or aquatic invertebrates was tested. However, sin ce both organisms are exposed when a pesticide enters an aquatic environment and the acute sen sitivity of an invertebrate may not accurately predict the chronic sensitivity in fish and vice versa, both species must now be tested for chronic effects. The Agency cannot make the assumption that a chemical is not chronically toxic at much lower concentrations than some ratio of the LC 50 value would suggest.

Practical Utility of the Data How will the data be used?

The data will be used to estimate potential risks to freshwater aquatic invertebrates and to reduce uncertainties associated with the current ecological risk assessment.

How could the data impact the Agency's future decision-making?

Without these data, the Agency cannot determine the levels of boric acid salts that could result in adverse effects to freshwater aquatic invertebrates. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for boric acid salts which may otherwise be avoided, or which are unnecessarily severe.

Guideline Number: 850.4100 Study Title: Seedling emergence, Tier II

Guideline Number: 850.4150 Study Title: Vegetative vigor, Tier II

Guideline Number: 850.4400 Study Title: Aquatic plant toxicity test using Lemna spp; Tier II

Guideline Number: 850.5400 Study Title: Algal toxicity, Tier II Rationale for Requiring the Data No toxicity data are currently ava ilable to assess the risk of boric acid salts to terrestrial or aquatic plants. Plants form the basis of most habitats and significantly contribute to overall environmental quality, and therefore a solid understanding of the potential risks to plants is essential for sound environmental management. While boric acid salts is applied as a foliar treatment to cotton and has not been reported to damage this plant, ther e are no data to determine if boric acid salts is phytotoxic to other terrestrial or aquatic plant taxa . Therefore, tier I testing for both aquatic and terrestrial plants is needed.

Since the boric acid salts RED was signed, the Agency has finalized its update to the data requirements in 40 CFR Part 158. In these update d data requirements, which were promulgated on October 26, 2007, Tier II seedling emergence (guideline 850.4100), Tier II vegetative vigor

21(guideline 850.4150) and aquatic plant growth (850.5400, 850.4400) studies are conditionally required for terrestrial uses for known phytotoxicants. Because boric acid salts are registered as herbicides, phytotoxicity is assumed and the Tier II teats are therefore required. Boric acid salt is registered for use on terrestrial crops, and therefore these data are required under the new 40 CFR Part 158 data requirements. Practical Utility of the Data

How will the data be used? The data will be used to estimate potential risks to terrestrial and aquatic plants, including the likelihood of potential risks to endangered species, eith er by direct effects or by indirect effects, and to reduce uncertainties associated with the curre nt ecological risk assessment. By refining the assessment, the Agency will be able to determin e whether current labeling is appropriate and whether further mitigation is necessary.

How could the data impact the Agency’s future decision-making? These data, once submitted, will allow the Agency to characterize the risk of boric acid salts to terrestrial and aquatic ecosystems. Primary producers ( i.e. plants) provide oxygen, food and habitat vital to ecological processes. Therefore, a solid understanding of the potential risks to plants is essential in order to assess the environmen tal risks the use of boric acid salts may pose. If the data indicate that boric acid salts poses signi ficant risks to these pl ant species, the Agency may explore additional decision options to minimize the risks to these species.

The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act and could result in u se restrictions for boric acid salts which may otherwise be avoided, or which are unnecessarily severe.

The Agency will however conduct a search of th e open literature to ensure that all best available science is utilized. The Agency uses the ECOTOX database as its mechanism for searching the open literature for ecological effects information. ECOTOX integrates three previously independent databases - AQUIRE, PHYTOTOX, and TERRETOX - into a system which includes toxicity data derived predominately from the peer-reviewed literature, for aquatic life, terrestrial plants, and terrestrial wildlife, respectively.

O THER I NFORMATION N EEDS

There is specific information that will assist the Agency in refini ng the ecological risk assessment, including any species-specific effects determinations. The Agency is very much interested in obtaining the following information:

1. confirmation on the following label information

a. sites of application b. formulations

c. application methods and equipment d. maximum application rates

22e. frequency of application, applicati on intervals, and maximum number of applications per season f. geographic limitations on use 2. use or potential use distri bution (e.g., acreage and geogr aphical distribution of relevant crops) 3. use history 4. median and 90 th percentile reported use rates (lbs. a.i./acre) from usage data – national, state, and county 5. application timing (date of first applica tion and application intervals) by crop – national, state, and county 6. sub-county crop location data 7. usage/use information for non-agricultural uses (e.g., forestry, residential, rightsof-way) 8. directly acquired county-level usage da ta (not derived from state level data)

a. maximum reported use rate (lbs. a.i./acre) from usage data – county b. percent crop treated – county

c. median and 90 th percentile number of applications – county d. total pounds per year – county

e. the year the pesticide was last us ed in the county/sub-county area f. the years in which the pesticide was applied in the county/sub-county area 9. typical interval (days) 10. state or local use restrictions 11. ecological incidents (non-target plant dama ge and avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency 12. monitoring data

The analysis plan will be revisited and may be revised de pending upon the data available in the open literature and the information s ubmitted by the public in response to the opening of the Registration review docket.

23L ITERATURE C ITED

Flickinger, E.L., D.H. White, C.A. Mitche ll, and T.G. Lamont. 1984. Monocrotophos and boric acid residues in birds as a result of misuse of organophosphates in Matagorda County, Texas. J. A ssoc. Off. Anal. Chem. 67:827-828.

U.S. Environmental Protection Agency. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of Research and Development, Washington, D.C. EPA/630/R-95/002F. April 1998.

U.S. Environmental Protection Agency. 2000. Risk Characterization Handbook. Science Policy Council, U.S. Environm ental Protection Agency, Washington, D.C. 20460. EPA 100-B-00-002. December 2000.

U.S. Environmental Protection Agency. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency. Endangered and Threat ened Species Effects Determinations. Office of Prevention, Pesticides and T oxic Substances, Office of Pesticide Programs, Washington, D.C.

USDA, Forest Service. 2006. Human heal th and ecological risk assessment for boric acid salts (Sporax) Final Repor t. Forest Health Protection, USDA Forest Service. Rosslyn Plaza Building C, Room 7129C 1601 North Kent StreetArlington, VA 22209

WHO (World Health Organization). 1998. Environmental health Criteria. Boron. Environmental Health Criteria 204.

24

## List of Impaired Waters

Click here to see metadata for this report. Query Parameters:

Cause of Impairm ent = BORON

NOTE: Click on the underlined Waterbody Name for a detailed Listed Water Report. Click on the underlin ed "MAP 303(d)" literal fo r a map of the Listed Water.

State Waterbody Name Map of Listed Water State Basin Name Location Cyles Listed

AZ GILA RIVER, CENTENNIAL WASH - GILLESPIE DAM No Spatial

Data HUC: 15070101 2004

AZ GILA RIVER, COYOTE WASH - FORTUNA WASH No Spatial

Data HUC: 15070201 2004

CA CALLEGUAS CREEK REACH 4 (WAS REVOLON SLOUGH MAIN BRANCH: MUGU LAGOON TO CENTRAL AVENUE ON 1998 303D LIST) MAP 303(d) LOS ANGELES 2002

CA CALLEGUAS CREEK REACH 7 (WAS ARROYO SIMI REACHES 1 AND 2 ON 1998 303D LIST) MAP 303(d) LOS ANGELES 2002

25CA CALLEGUAS CREEK REACH 8 (WAS TAPO CANYON REACH 1) MAP 303(d) LOS ANGELES 2002

CA CHOLAME CREEK MAP 303(d) CENTRAL COAST 2002

CA FOX BARRANCA (TRIBUTARY TO CALLEGUAS CREEK REACH 6) MAP 303(d) LOS ANGELES 2002

CA MUD SLOUGH MAP 303(d) CENTRAL VALLEY 2002, 1998

CA ORCUTT SOLOMON CREEK MAP 303(d) CENTRAL COAST 2002

CA SALT SLOUGH (UPSTREAM FROM CONFLUENCE WITH SAN JOAQUIN RIVER) MAP 303(d) CENTRAL VALLEY 2002

CA SAN ANTONIO CREEK (SAN ANTONIO WATERSHED, RANCHO DEL LAS FLORES BRIDGE AT HWY 135 TO DOWNSTREAM AT RAILROAD BRIDGE) MAP 303(d) CENTRAL COAST 2002

CA SAN JOAQUIN RIVER (BEAR CREEK TO MUD SLOUGH) MAP 303(d) CENTRAL VALLEY 2002

CA SAN JOAQUIN RIVER MAP 303(d) CENTRAL VALLEY 2002

26(MENDOTA POOL TO BEAR CREEK)

CA SAN JOAQUIN RIVER (MERCED RIVER TO SOUTH DELTA BOUNDARY) MAP 303(d) CENTRAL VALLEY 2002

CA SAN JOAQUIN RIVER (MUD SLOUGH TO MERCED RIVER) MAP 303(d) CENTRAL VALLEY 2002

CA SAN LORENZO CREEK MAP 303(d) CENTRAL COAST 2002

IL MARKHAM CREEK MAP 303(d) UPPER ILLINOIS 2004, 2002

IL S. FK. SANGAMON RIVER MAP 303(d) LOWER ILLINOIS 2004, 2002

IL SALINE BR. MAP 303(d) WABASH RIVER 2004, 2002

IL SANGAMON RIVER MAP 303(d) LOWER ILLINOIS 2004, 2002

IL SUGAR CREEK MAP 303(d) 2004, 2002, 1998

IL SUGAR CREEK MAP 303(d) 2004, 2002, 1998

KS ARKANSAS RIVER No Spatial

Data UPPER ARKANSAS STATION/SEGMENT: 286_1 2002

KS ARKANSAS RIVER MAP 303(d) UPPER ARKANSAS STATION/SEGMENT: 594_1 2002

KS ARKANSAS RIVER MAP 303(d) UPPER ARKANSAS STATION/SEGMENT: 594_11 2002, 1998, 1996

KS ARKANSAS RIVER No Spatial

Data UPPER ARKANSAS STATION/SEGMENT: 594_10 2002

27KS DOOLEYVILLE CREEK MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_8 2002

KS GOOSE CREEK MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_10 2002, 1998, 1996

KS NORTH FORK NINNESCAH RIVER MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_6 2002, 1998, 1996

KS NORTH FORK NINNESCAH RIVER MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_5 2002, 1998, 1996

KS RED ROCK CREEK MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_12 2002, 1998, 1996

KS SILVER CREEK MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_7 2002, 1998, 1996

KS UNNAMED STREAM MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_289 2002

KS WOLF CREEK MAP 303(d) LOWER ARKANSAS STATION/SEGMENT: 525_9 2002

NV HUMBOLDT RIVER MAP 303(d) HUMBOLDT BASIN BATTLE MTN TO COMUS 2004, 2002

NV HUMBOLDT RIVER MAP 303(d) HUMBOLDT BASIN RODGERS DAM TO HUMBOLDT SINK 2004, 2002

NV MAGGIE CREEK MAP 303(d) CONFLUENCE WITH JACK CREEK TO HUMBOLDT RIVER 2002

NV MUDDY RIVER MAP 303(d) COLORADO RIVER BASIN GLENDALE TO LAKE MEAD 2004, 2002

NV STEAMBOAT CREEK MAP 303(d) TRUCKEE RIVER BASIN SEC 33, T18N, R20E TO TRUCKEE RIVER 2002

NV STILLWATER MARSH MAP 303(d) CARSON RIVER BASIN AREA OF STILLWATER MARSH EAST OF WESTSIDE ROAD AND NORTH OF THE COMMUNITY OF STILLWATER 2004, 2002

NV VIRGIN RIVER MAP 303(d) COLORADO RIVER BASIN STATELINE TO MESQUITE 2004, 2002

28MAP 303(d) NV VIRGIN RIVER COLORADO RIVER BASIN MESQUITE TO LAKE MEAD 2004, 2002

NV WEST WALKER RIVER MAP 303(d) WALKER RIVER BASIN STATELINE TO WELLINGTON 2004, 2002

UT PARIETTE DRAW MAP 303(d) UINTA RIVER BASIN PARIETTE DRAW & TRIBS: FROM COFLUENCE WITH GREEN RIVER TO HEADWATERS 2002, 2000, 1998

UT SALT LAKE CANAL No Spatial

Data WEBER RIVER HEXCEL CORP.- SL OPERATIONS 2002

UT UNNAMED DRY WASH No Spatial

Data CEDAR/BEAVER RIVER AMERICAN AZIDE CORPORATION 2002



## List of Approved TMDLs

Click here to see metadata for this report. Query Parameters:

Pollutant = BORON

NOTE: Click on the underlined TMDL Document Name to see a detailed TMDL report. Click on t h underlined Listed Water Impairment Name to see appli cable listed waters for the TMDL. EPA is i n process of collecting TMDL info rmation from the states. Because these efforts are on-going, ther e additional approved TMDLs that were not included in the listings below.

State TMDL Document Name TMDL Pollutant TMDL Establishment Date EPA Action Listed Water Cause of Impairment Cycles Listed

CO APACHE CANYON COALBED METHANE TMDL BORON DEC-03-2001 EPA APPROVED None Reported None Reported

CO FLORIDA RIVER BORON DEC-10-2001 EPA APPROVED AMMONIA 1996

CO RALSTON CREEK - COTTER CORPORATION SCHWARTZWALDER MINE BORON SEP-23-2005 EPA APPROVED PLACEHOLDER TO PROVIDE LINKAGE FOR UNLISTED IMPAIRMENTS AND/OR UNLISTED WATERS None Reported

29BORON SEP-11-2000 EPA APPROVED BORON KS ARKANSAS RIVER 1998

KS ARKANSAS RIVER BORON SEP-11-2000 EPA APPROVED BORON 1998

KS ARKANSAS RIVER BORON SEP-11-2000 EPA APPROVED BORON 1998

KS ARKANSAS RIVER BORON SEP-11-2000 EPA APPROVED BORON 1998

KS ARKANSAS RIVER BORON SEP-11-2000 EPA APPROVED BORON 1998

NV VIRGIN RIVER (STATELINE-L. MEAD) BORON JAN-14-2003 EPA APPROVED BORON 1998, 1996

30