1 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

 

June 18, 2013 

Ms. Donna Wieting, Director 

Office of Protected Resources 

United States Department of Commerce 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Silver Spring, MD 20910 

Dear Ms. Wieting: 

This letter provides both EPA's comments and a summary of public comments on the National 

Marine Fisheries Service’s (NMFS) May 1, 2013 Draft Biological Opinion (BiOp) pertaining to 

the potential effects of products containing diflubenzuron, fenbutatin oxide, and propargite to 

federally listed threatened or endangered Pacific salmon and steelhead and their critical habitat, 

if designated. The Draft BiOp addresses formal consultations EPA initiated with NMFS between 

2002 and 2004, based on potential risks to the subject species from the registered uses of 

diflubenzuron, fenbutatin oxide, and propargite. All of the public comments received on this 

draft BiOp are available at: http://www.regulations.gov/#!docketBrowser;rpp=25;so=DESC;

sb=postedDate;po=0;dct=PS;D=EPA-HQ-OPP-2008-0654. 

EPA looks forward to working collaboratively and expeditiously with NMFS, the U.S. Fish and 

Wildlife Service, and the U.S. Department of Agriculture to review the recent recommendations 

provided in the 2013 National Academy of Science (NAS) report “Assessing Risks to 

Endangered and Threatened Species from Pesticides" and to identify potential improvements in 

the current scientific procedures used in evaluating the potential impacts of pesticides to 

endangered and threatened species. This review is not complete, and the agencies have not yet 

decided on how to proceed with ongoing actions or planned future actions. As we reach mutual 

agreement on how to proceed and as timing allows, EPA suggests that NMFS consider advice 

provided in the report in the final opinion.

Potential Errors in the Draft BiOp 

One public commenter noted that the figure on page 74 lists thiobencarb as a stressor of the 

action, which appears to be a holdover from the previous BiOp. Thiobencarb should be removed 

as this draft BiOp pertains to diflubenzuron, fenbutatin oxide, and propargite. 
2 

The same public commenter noted that on page 286, NMFS states that the contributing adverse 

effects on the environmental baseline and salmonids of chemicals evaluated in previous Opinions 

(2008, 2009) “continue today as the EPA has yet to implement the conservation measures 

(reasonable and prudent alternatives and measures) identified in the previous Opinions.” It 

should be noted that in February of this year the Fourth Circuit Court of Appeals concluded that 

“the BiOp was not the product of reasoned decision-making in that the Fisheries Service failed to 

explain or support several assumptions critical to its opinion. To enable a renewed agency 

process, we vacate the BiOp and remand this case to the district court with instructions to 

remand it to the Fisheries Service for further proceedings consistent with this opinion.” Given 

the status of the BiOp, NMFS should remove the reference to the 2008 BiOp from this draft 

BiOp. 

On page 505, NMFS states that no endocrine studies have been submitted for any of the 

pesticides. However, a fish reproduction study that measured endocrine endpoints was provided 

to NMFS (York, MRID 48618906). EPA also notes that fenbutatin oxide and propagarite are on 

the first list of chemicals for initial Tier I testing for the Endocrine Disruptor Screening Program 

(http://www.epa.gov/scipoly/oscpendo/pubs/final_list_frn_041509.pdf) and the data are currently 

under evaluation. 

The multiple references to nonylphenolics should be substantiated or removed as the registrant 

for diflubenzuron and propargite has informed NMFS that these compounds are not used in its 

formulations as documented by the Confidential Statements of Formula. 

Tables 171, 172, and 173 all say “propargite” in the table even though the other chemicals 

(diflubenzuron, fenbutatin oxide, and propargite) are specified, respectively. This also applies 

for Tables 174, 175, and 176. These tables should be revised to include the appropriate chemical 

in each table. 

Exposure Analysis (pgs. 379 – 424) 

EPA commends NMFS on their effort to spatially and temporally refine the overlap between 

uses of diflubenzuron, fenbutatin oxide, and propargite and listed salmonid occurrence that has 

been made in this BiOp. Chemical-specific comments on the exposure analysis are provided 

below. 

Diflubenzuron 

Several of the diflubenzuron estimated average concentrations reported in Table 74 (page 395) 

exceed the cited solubility limit (0.02 mg/L) for diflubenzuron. This solubility limit is no longer 

considered accurate and has been updated (0.08 mg/L) in the “Registration Review: Problem 

Formulation for the Environmental Fate, Ecological Risk, Endangered Species, and Drinking 

Water Exposure Assessments for Diflubenzuron” document (USEPA, 2012)1

. While most of the 

 

1 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2012-0714-0005
3 

results in Table 74 still exceed this revised solubility limit, EPA wanted to ensure NMFS was 

aware of this change. 

Likewise, the reported log Kow of 7.38 ± 0.35, as cited in Table 65 (page 374), is not correct for 

diflubenzuron. The log Kow is 3.70, as reported in EPA’s registration review problem 

formulation document (USEPA, 2012). EPA recommends revising the solubility and log Kow

values in Table 65. 

Fenbutatin oxide 

EPA believes that it is important to characterize the modeled and measured concentrations used 

as exposure estimates for fenbutatin oxide. Many reported model values are above the solubility 

limit, which in most cases would not be expected in the natural environment. However, NMFS 

should clarify that in some instances the concentration of an active ingredient may exceed its 

solubility limit. 

The following characterization was provided in EPA’s 2007 “Ecological Risk Assessment for 

Fenbutatin-Oxide Section 3 New Use on Pistachios”2

: 

The solubility of fenbutatin oxide is approximately 12.7 μg/L, however, the aquatic EECs 

for several of the currently registered uses of fenbutatin oxide exceed the solubility limit. 

It is unclear if fenbutatin oxide could be present at super-saturated concentrations in 

water bodies immediately post application for enough time to produce acute effects in 

sensitive organisms. Additionally, it is unclear whether or not fenbutatin oxide that is 

bound in the upper soil horizons could periodically wash into surface water as soilbound residue and cause periodic acute toxicity to organisms. To explore the risks 

associated with the uses that produced the highest EECs, we calculated RQs based on the 

solubility limit for the chemical. This resulted in a risk picture similar to the proposed 

pistachio use and the raspberry use (i.e., acute and chronic RQs that exceed the agency's 

LOCs for all aquatic animals except for the chronic RQ for the freshwater invertebrates). 

Surface water sampling in ponds and canals was conducted immediately after treatments 

in an aquatic residue study conducted in Florida. After peaking at less than 1μg/L in 

pond water in conjunction with applications, fenbutatin oxide residues declined to less 

than the level of quantification (LOQ) of 0.10 μg/L in 1-2 days. After peaking at typically 

> 10 μg/L to as much as 111 μg/L in some perimeter/lateral canal water samples in 

conjunction with applications, maximum fenbutatin oxide concentration typically 

declined to <5 μg/L within 14 days after each application, but remained above the LOQ 

for the 60 day post-application study period. These concentrations (>10 μg/L to as much 

as 111 μg/L) approached and greatly exceeded the reported solubility of the compound 

creating a supersaturated condition. According to the study author, the freshwater and 

 

2

 Panger, M., McKinnon, A. 2007. Ecological Risk Assessment for Fenbutatin-Oxide Section 3 New Use on 

Pistachios. USEPA, EFED, DP Barcode 328390. August 24, 2007 
4 

brackish water flatwood groves with shallow aquifers and extensive ditch and canal 

systems all had much higher levels of fenbutatin-oxide in surface water in their 

perimeter/lateral canals than in the ponds (MRID: 42872101 [Wallace, 1993]). It is 

unclear whether the compound is bioavailable for uptake by aquatic organisms during 

the time period between the application of fenbutatin oxide and when the compound 

partitions to sediment. Several issues regarding this study require further review, 

including: determining whether or not the analytical method used has been reviewed and 

accepted; determining whether or not the samples were filtered; if total suspended solids 

were accounted for in the water samples; and storage stability issues.

Propargite 

EPA has no comments on the endpoint selection for propargite. 

Public Comments on the Exposure Analysis

Modeling Issues

A public commenter indicated that watershed-scale models, such as the Soil and Water 

Assessment Tool (SWAT), should be used to determine the likelihood that potential 

concentrations of the three pesticides in intermittent streams, drainages and ditches, would 

threaten salmon or their critical habitat. Otherwise, protecting freshwater habitats appears to be a 

“no exposure” approach instead of a risk-based approach. 

One public commenter indicated that the NMFS exposure assessments do not incorporate 

temporal fluctuations, water movement, or salmon life-stage habitat. Rather, the assessments 

assume that fish are exposed to stagnant, shallow 10-cm water throughout the year. These 

assumptions are due to the use of the AgDRIFT model rather than the more realistic 

PRZM/EXAMS model. NMFS should have used AGDISP which was developed specifically for 

forests. 

One public commenter indicated that NMFS’ generalized land use categories, versus specific 

crop uses, exaggerate the potential co-occurrence of the critical habitat of the ESU with 

propargite or diflubenzuron. 

Lack of Inclusion of Submitted Data

A public commenter indicated that extensive information had been submitted to NMFS on 

diflubenzuron, specifically regarding the labels, usage, environmental fate and transport, mode of 

action and synergism, sublethal effects, degradate toxicity, formulation toxicity, and existing 

protections (Gagne 20113

). Although there was a citation to this paper in the NMFS BiOp, on 

 

3 Gagne, J.A. (2011). Diflubenzuron exposure and potential effects on threatened and endangered Pacific salmonids. 

Compliance Services International, Lakewood, WA; Project ID CSI 11701. MRID 48531101.
5 

page 560, it appears that the actual reference is to Gagne et al. (2013, MRID 49094601). There 

is no citation to Gagne, 2011 in the References section of the draft BiOp and it does not appear 

that the information from this paper was used. Lastly, it is not clear how the propargite water 

monitoring data represent the current label and restrictions. 

Response Analysis (pgs. 434 – 512, pgs. 559-562) 

Diflubenzuron 

EPA has the following comments on the reported diflubenzuron toxicity data for invertebrates 

(Table 88): 

(a) The reported toxicity data did not include MRID 00038612, a study on acute toxicity to 

grass shrimp reported in EPA’s California Red-legged Frog assessment (USEPA, October 

20094

). It is also noted that the grass shrimp data included in Table 88 (Wilson and Costlow, 

1986 and 1987; Touart and Rao, 1987) were not deemed acceptable in the ECOTOX 

database due to a lack of controls. 

(b) The ECOTOX database contains data on Americamysis bahia (Mysidopsis bahia) that 

may be useful in estimating the toxicity of diflubenzuron to mysids (ECOTOX #4891 and 

#111352). 

(c) The value reported for Kasai et al., 2007 is the LC99 as reported in the ECOTOX 

database. ECOTOX reports the LC50 = 0.55 μg/L. 

(d) EPA is not certain where the reported blackfly larvae (Simulium vittatum) endpoint of 1.3 

μg/L came from, as the provided citation “EFED database, 2000” is vague. However, there 

are additional data for this species reported in the ECOTOX database (LC50 = 6 μg/L and 330 

μg/L; ECOTOX #12088). 

The 10th percentile effect concentration for diflubenzuron (0.12 μg/L, Figure 77) is based on the 

distribution of EC50s for aquatic invertebrates; therefore it should be recalculated after any 

changes to the dataset are made (e.g., inclusion/exclusion of the data described above). 

Fenbutatin oxide 

EPA has no comments on the endpoint selection for fenbutatin oxide. 

Propargite 

EPA has no comments on the endpoint selection for propargite. 

 

4 http://www.epa.gov/oppfead1/endanger/litstatus/effects/redleg-frog/index.html#diflubenzuron
6 

Public Comments on the Response Analysis

 Toxicity Data, Quality Rankings

Several public commenters noted that data and information reviewed for each assessment 

endpoint were assigned a qualitative ranking of either “low,” “moderate,” or “high.” It is good 

that some assessment of the quality of the data used in the BiOp is made. However, the basis for 

ranking and criteria for scoring should be available. On page 509, NMFS lays out the criteria for 

the qualitative assignment. These criteria include the following. The test species should be a 

listed species or “appropriate surrogate” which is undefined. The experiment should be “well 

conducted” which is undefined, and done with stressors of the action or “relevant chemical 

surrogates” which are also undefined. It is not possible to evaluate how NMFS actually selected 

studies to use in its assessment. Tables 92-94 show that the categories of low, moderate, and 

high actually reflect NMFS’ degree of confidence in the effects, and are not a study classification 

as such. Furthermore, the tables are structured so that it is not readily apparent which studies 

NMFS is relying on. 

Diflubenzuron Toxicity Data

A public commenter noted that the mode of action of diflubenzuron is clearly different from the 

modes of action for fenbutatin oxide and propargite. However, NMFS uses the growth model for 

all three compounds. The growth model is particularly important because it is an important line 

of evidence for determining indirect effects and adverse habitat modification for diflubenzuron. 

One public commenter indicated that NMFS used a single daphnid EC50, which suggests a 48-hr 

exposure. There is no explanation for why this interval is justified for propargite, but a different 

interval is justified for diflubenzuron, especially when NMFS used the growth model for both 

compounds. 

RPAs (pgs. 699 – 714) 

1. Element 1. Implementation of chemical-specific no-spray buffers 

As the implementation of these buffers is for mitigation of risk to salmonids, NMFS should 

move beyond a screening-level approach and consider and incorporate site-specific conditions, 

as well as drift reduction technologies, that might reduce the “one size fits all”-type buffer 

presented in RPA 1. 

While it is apparent that NMFS developed buffer distances for aerial and ground applications 

that resulted in different pesticide concentrations in receiving waters, it remains unclear as to 

why such buffers should be viewed equally protective in avoiding jeopardy when it is a 

fundamental axiom that the exposure level is an important determinant of individual organism 

risk. NMFS should provide a more descriptive and detailed account of how they evaluated 

whether buffers would protect salmon at the population level and how the resultant receiving 
7 

water concentrations expected from proscribed buffers cascade from expected effects to 

individuals to populations. Furthermore, the biological opinion would benefit greatly with the 

addition of a more thorough technical explanation as to how the population models were used to 

determine if the action would affect salmonids at the population level. 

On page 710, NMFS indicates the following for the no-spray buffers: 

“The degree to which expected exposure to the a.i. overlaps with response endpoints varies 

somewhat at different buffer sizes and among the three a.i.s. This is due, in part, to qualitative 

considerations made in assigning the buffers and recognition of inherent uncertainty associated 

with these estimates. For example, AgDRIFT estimates associated with aerial application of 

diflubenzuron at buffers of 500-1000 ft exceed concentrations predicted to cause population level 

responses associated with reductions in prey. However, we considered that AgDRIFT has a 

tendency to overpredict drift at larger buffer distances (Bird et al. 2002). Therefore we expect 

the predicted concentrations at these buffer distances to occur infrequently.” 

NMFS should provide information on how specific buffer distances were established and clarify 

what qualitative considerations were made, given that the expected exposure concentrations 

exceed the response endpoints. As presented, the derivation of the proposed buffers is unclear 

and appears arbitrary. In addition, NMFS should provide further information on the extent to 

which the buffers may be reduced taking into account “qualitative considerations”, as well 

situations where factors controlling spray drift (i.e., droplet size, release height, and wind speed) 

may influence buffer sizes. 

With regards to the fenbutatin oxide no-spray buffers, although EPA uses a different 

methodology to estimate no-spray buffers, the estimates developed by EPA, using screeninglevel input parameters (e.g., spray droplet size distribution of very fine) are in line with those 

developed by NMFS. 

Public Comments on RPA 1

One public commenter stated that RPA 1 specifies no-spray buffers required for each of the three 

active ingredients (up to 1000 ft. for aerial application and up to 500 ft. for ground application, 

depending on a.i.) with specified maximum application rates that cannot be exceeded. NMFS 

showed example graphs of effects endpoints with buffer exposure estimates but it was not clear 

how these buffer values were determined. This should be clearly provided, so that anyone can 

repeat the analysis conducted in the BiOp and understand how the conclusions were reached. 

A public commenter indicated that NMFS made efforts to qualify the strength of each source in 

terms of its level of uncertainty and its ability to contribute to the risk assessment. However it is 

still unclear how NMFS specifically considered much of the qualitative evidence in the 

determination of jeopardy and in outlining RPA 1. It is not clear how NMFS weighted each line 

of qualitative evidence against another or how they were accounted for in the final 

determinations. It would be extremely helpful to readers of this document if NMFS went through 
8 

the lines of qualitative evidence or gave several detailed examples of how the lines of evidence 

were used in determining the buffers in RPA 1. Additionally, a description as to the impact they 

have on buffer size determination in terms of increasing or decreasing specific distances and the 

degree to which this could account for gains in protection would enhance support for the 

conclusion contained in the document. 

One public commenter expressed that because drainages and ditches are required to be buffered 

by NMFS (not on the EPA label), these buffers (particularly in high precipitation areas) will 

essentially eliminate most ground applications of diflubenzuron, and aerial applications of 

propargite and diflubenzuron. 

One public commenter indicated that NMFS must factor in both seasonal rainfall and irrigation 

method when proposing buffers for propargite, fenbutatin oxide, and diflubenzuron. The buffers, 

as currently proposed, present a one-size-fits-all approach that is unreasonable for many crops. 

For fenbutain oxide and propargite particularly, mite outbreaks are most severe in hot, dry, and 

dusty conditions; conditions that obviously exist in areas with little rainfall. Low seasonal 

rainfall means less chance of runoff carrying pesticides into salmon-bearing waters. Likewise in 

crops using drip irrigation, there is less likelihood that over irrigation will carry pesticides off 

site. 

One public commenter feels that NMFS has not considered existing water quality programs. In 

places where water quality programs already exist and where it can be demonstrated that they are 

protective of salmon-bearing streams, the buffer requirements outlined in the BiOp should be 

lifted. One effective California water quality regulatory program is the Irrigated Lands 

Regulatory Program (ILRP) under the Central Valley Regional Water Quality Control Board 

(part of the State Water Resources Control Board). 

One public commenter felt the buffer zones with no vegetative buffer (300 ft. for propargite) 

would be almost as large as the entire treated area. The buffer zones do not account for the size 

of fields, only the application rate. With the exception of some wastewater ways for irrigation 

project drainage, there are not many lands near irrigated fields that would be considered riparian. 

According to this public commenter, the riparian area option (Element 3 in the BiOp) is not a 

realistic option. 

One public commenter recommends that NMFS factor use patterns into the buffers proposed in 

the draft BiOp. Low use equals low risk and a reduced need to create buffers. The public 

commenter also indicated that if the buffers proposed for fenbutatin oxide are applied to 

irrigation canals, they are unworkable. It is not clear (without appropriate data) how applications 

near non-salmon bearing water affect salmonids, especially given the possible large spatial 

separation between application site and the salmon-bearing water. 
9 

2. Element 2. Application of reduced no-spray buffers with a maintained vegetated filter 

strip ≥ 30 feet. 

On page 430 of the Draft BiOp, NMFS states “We also consider runoff a likely pathway of 

exposure although environmental fate characteristics suggest it may be less important than drift 

as none of the three a.i.s are particularly mobile in soil.” Given the relatively low solubility of 

the three pesticides (0.013-0.6 mg/L) along with the low potential for mobility (Koc values 

ranging from 2,000 to 320,000 L/kgoc), EPA believes that the majority of runoff from fields 

treated with these pesticides would be bound to eroded soil rather than mixed with water. While 

vegetative buffers have the potential to mitigate pesticide movement due to soil erosion, EPA 

questions the validity of the use of a vegetative filter strip as means to mitigate exposure in 

aquatic habitats via runoff when spray drift is the primary route of exposure. Additionally, no 

rationale is provided regarding the extent to which a vegetative filter strip would result in a 

reduction of the no-spray buffer distances by up to 25%. Generally, when EPA considers the 

impact of spray drift buffers and vegetative filter-strips, the analysis is done independently, since 

the transport routes are separate and mitigation of one route does not impact the other route. 

NMFS should clarify exactly how the no-spray buffer would be reduced with a maintained 

vegetated filter strip, how one would determine the reduction in the no-spray buffer, and how 

one will one ensure that the vegetated filter strips will be “maintained”. 

Public Comments on RPA 2

Several public commenters indicated that it was unclear whether the no-spray buffers distances 

prescribed in RPA 2 begin from the edge of field, and therefore include the >30ft vegetated filter 

strip, or whether no-spray buffers start at the inner edge of the >30ft vegetated filter strip. 

Furthermore, it is unclear what criteria was used to define 30 feet as the minimum distance or 

why further reductions in no-spray buffer distances were not considered if larger vegetated filter 

strips were in place. The public commenter also noted that the BiOp did not mention other 

specifications or give directions to technical guidance as to how filter strips should be created or 

maintained. The BiOp also did not explain if the potential benefit of having a vegetated filter 

strip was evaluated and whether a quantitative method (similar to Element 1) was used to 

determine the reduction in no-spray buffer size for RPA 2. Perhaps NMFS could describe this in 

more detail or illustrate this with figures similar to those used in RPA 1 (Figures 85, 86, and 87). 

NMFS did not provide a rationale for why reductions in no-spray buffer distances were 

considered for the >30 ft vegetated filter strip but not for other types of conservation buffers (i.e., 

vegetative barriers, herbaceous wind barriers, riparian forest buffers, etc.). These other 

conservation buffers would similarly provide potential reductions in pesticide drift and reduced 

runoff of the chemicals included in the current action as well as other pesticides and adjuvants 

that may degrade water quality and potentially pose a threat to salmonids and their habitat. 

NMFS should consider applying the same reduction to no-spray buffers considered for >30 ft 

vegetated filter strips to other types of USDA NRCS recognized conservation buffers which is in 

part suggested in RPA 3 of the BiOp. 
10 

NMFS is proposing the use of vegetative buffer strips. In growing regions where there is low 

rainfall, maintaining these buffer strips would require the application of irrigation water. One 

public commenter is concerned that this additional water requirement might not, in and of itself, 

be protective of salmonids. Increasing the demand for irrigation water seems counterproductive 

to protecting salmon populations. Pressure currently exists to reduce the amount of water used 

for irrigation to protect salmon populations by increasing the flows in salmon-bearing waters. 

While vegetative buffer strips might be relatively easily established and maintained during the 

winter months in the Sacramento Valley (where there is on average more than 25 inches of 

rainfall), irrigation would be necessary to maintain buffer strips during the summer months. The 

further south in the San Joaquin Valley, the less likely it is that vegetative buffer strips could be 

maintained as there is insufficient rainfall even in the winter months. 

A public commenter asked why NMFS did not consider low-drift application methods for RPAs 

1 and 2. A public commenter also suggested that landowners’ current stewardship efforts should 

also be taken into account for RPA 2. 

3. Element 3. Use of riparian areas to reduce pesticide loading negating the need for nospray buffers. 

NMFS is proposing the use of riparian areas (e.g., vegetated buffer areas between treated fields 

and waterbodies used to filter, transform, and absorb pesticides) to reduce pesticide loading and 

possibly negating the need for no-spray buffers. NMFS proposes a coordinated effort between 

EPA, USDA’s Natural Resources Conservation Services (NRCS), and others in exploring the use 

of riparian areas, such that qualified personnel could verify the effectiveness of riparian areas at 

removing pesticides, and a reduced set of no-spray buffers, or the alleviation of a no-spray 

buffer, would be credited to the land owner. EPA agrees that the use of riparian areas has the 

potential to reduce pesticide loading via runoff and spray drift and that this RPA has the potential 

to be an effective means at reducing pesticide loading to waterbodies. The use of this measure on 

a label or Endangered Species Protection Program (ESPP) Bulletin may present some challenges, 

given that the effects of riparian areas are pesticide-specific, site-specific, and temporallyspecific, and currently, EPA does not have the means to evaluate their effectiveness. EPA is 

open to working with NMFS and USDA to further develop the use of riparian areas for 

protecting endangered species and also minimize impacts to grower operations. Alternatively, 

drift reduction technologies, such as low-drift nozzles, addition of adjuvants, and the use of 

physical drift reduction devices (e.g., spray shields, cones, etc.), can be applied objectively in 

reducing or eliminating no-spray buffers. Additionally, EPA is currently finalizing its protocol 

for the evaluation of drift reduction technologies (DRTs), allowing for their implementation in an 

economically feasible manner. 
11 

Public Comments on RPA 3

A public commenter indicated that NMFS should change the definition for “riparian area” in 

RPA 3. The mention of pesticides should be deleted, as riparian areas exist in many areas 

without pesticide usage. Riparian areas may also contain non-native vegetation. The public 

commenter suggested the following: Riparian areas occur along watercourses or water bodies, 

and they are distinctly different from the surrounding lands because of unique soil and vegetation 

characteristics that are strongly influenced by unbound water in the soil. 

A public commenter indicated that the use of the term “buffer” for both no-spray and riparian 

was confusing. NMFS should consider using “buffer” for one or the other, but not both; i.e., nospray zone and riparian buffer or no-spray buffer and riparian area. Additionally, the more 

effective a riparian area is at pesticide removal, the narrower the no-spray buffer could be. 

A public commenter noted that RPA 3 requires USDA’s NRCS and EPA to develop a novel 

approach which could take years to implement. A public commenter questioned whether NMFS 

would permit enough time for “a novel system” to be developed. Otherwise, RPAs 1 and 2 

would be the only alternative for growers who would be heavily and negatively impacted. 

Terms and Conditions (pgs. 719-720) 

Term and Condition 1.a EPA shall not authorize application of pesticide products when wind 

speeds are greater than or equal to 10 mph. 

EPA recommends that wind direction, as well as wind speed, should be considered. NMFS 

should specify whether or not they would consider different buffers depending on the wind 

direction. 

Term and Condition 1.b EPA shall not authorize application of pesticide products when soil 

moisture is at field capacity, or when a storm event likely to produce runoff from the treated area 

is forecasted (by NOAA/National Weather Service, or other similar forecasting service) to occur 

within 48 hours following application. 

In EPA’s responses to previous draft BiOps, EPA has stated that there is confusion surrounding 

the term “field capacity”. EPA previously recommended that the Term and Condition be 

changed to indicate that applications may not be made when the “soil is saturated.” 

EPA also previously recommended that NMFS consider whether this Term and Condition would 

more appropriately limit pesticide application when soil is saturated AND when a storm event 

likely to produce direct runoff to salmonid-bearing water from the treated area is forecasted. It 

was argued that both soil saturation and a rain event is what would lead to runoff. It was further 

suggested that NMFS include in this Term and Condition a suitable rainfall probability to inform 

when rainfall is considered “likely.” For example, this Term and Condition may be more 

meaningful if it were to specify a specific threshold probability of a storm event of a certain 
12 

magnitude, such as when the potential for a significant storm event is greater than 50% (or some 

other suitable rainfall probability). This would provide flexibility to continue operations when 

the probability of an event is low or when even though high in probability, the event itself is 

inconsequential such as “occasional rain” or “light drizzle” is predicted as is said to often be the 

case in parts of the Pacific Northwest. 

EPA also questioned the need to predict rainfall events that may occur within 48 hours and asked 

for an explanation of why 48 hours is appropriate rather than 24 hours or some other time frame. 

Terms and Condition 1.c Report all incidents of fish mortality that occur within the vicinity of 

the treatment area, including areas downstream and downwind, in the four days following 

application of and of these a.i.s to EPA’s Office of Pesticide Programs. Alternatively, these 

incidents may be reported to the pesticide manufacturer through the phone number on the 

product label once EPA modifies FIFRA 6(a)2 to require registrants to report all fish kills 

immediately, regardless of incident classification (i.e. both minor and major incidents). Within 

one year of receipt of this Opinion, EPA shall submit an annual report to NMFS Office of 

Protected Resources that identifies the total number of fish affected and incident locations.

EPA appreciates the revision of this term, as compared to those in previous BiOps, to include the 

alternative for incidents to be reported as stipulated on the product label. 

Term and Condition 1.d EPA shall, in close coordination with NMFS Office of Protected 

Resources, develop and implement an effectiveness monitoring plan for floodplain habitats, and 

produce annual reports of the results. The plan shall identify representative floodplain habitats 

prone to drift and runoff of pesticides within agricultural areas. The representative floodplain 

habitat sampling sites shall include floodplain habitats currently used by threatened and 

endangered Pacific salmonids, as identified in coordination with NMFS Office of Protected 

Resources. Sampling sites include at least two sites for each general species (i.e., coho salmon, 

chum salmon, steelhead, sockeye salmon, and ocean-type Chinook and stream-type Chinook 

salmon). Sampling shall consist of daily collection of surface water samples for seven 

consecutive days during three periods of high application of these a.i.s. Collected water samples 

will be analyzed for the three active ingredients. A report summarizing annual monitoring data 

and including all raw data shall be submitted to NMFS Office of Protected Resources and will 

summarize annual monitoring data and provide all raw data. 

EPA has commented on this Term and Condition in relation to previous BiOps and will continue 

discussions with NMFS on the purpose and design of this proposed requirement. If it is 

determined that monitoring data are necessary, EPA can work with NMFS to design a reasonable 

monitoring study which will allow the federal government to determine peak concentrations of 

the pesticides in these vulnerable habitats and at the same time provide information and data that 

might allow EPA to determine the effectiveness of its modeling in determining potential 

exposures in such habitats. EPA would also seek the input of the U.S. Geological Survey in 

developing such a protocol with NMFS. 
13 

Term and Condition 2.a EPA shall include the following instructions requiring reporting of 

fish kills either on the labels for all products containing diflubenzuron, fenbutatin oxide, or 

propargite in ESPP Bulletins:

NOTICE: Incidents where salmon appear injured or killed as a result of pesticide 

applications shall be reported to NMFS Office of Protected Resources at 301-713-1401 

and EPA's Office of Pesticide Programs. The finder should leave the fish alone, make 

note of any circumstances likely causing the death or injury, location and number of fish 

involved, and take photographs, if possible. Adult fish should generally not be disturbed 

unless circumstances arise where an adult fish is obviously injured or killed by pesticide 

exposure, or some unnatural cause. NMFS Office of Protected Resources or Office of 

Law Enforcement may request the finder to collect specimens or take other measures to 

ensure that evidence intrinsic to the specimen is preserved. 

EPA requires pesticide registrants to provide information regarding incidents to EPA through a 

system established under section 6(a)(2) of FIFRA. EPA would request that NMFS provide to 

EPA any reported incidents on listed salmonids related to diflubenzuron, fenbutatin oxide, or 

propargite exposure. 

Public Comments, Term and Condition 2.a

One public commenter indicated that the draft BiOp does not spell out what happens if there is a 

fish-kill that is found to be linked to pesticide use. It does not appear that the draft BiOp 

currently addresses the basic, critical issues necessary to determine whether listed species - and 

treaty-reserved fishing rights - are being adequately protected. 

One public commenter remarked that according to NMFS (page 719, Term 1c.), all incidents of 

fish mortality that occur within the vicinity of the treatment area need to be reported to EPA’s 

Office of Pesticide Programs, or alternatively to the pesticide manufacturer. However in contrast, 

the label is required to have a statement which indicates that such incidents shall be reported to 

NMFS Office of Protected Resources and EPA’s Office of Pesticide Programs (page 720, Term 

2a.). In either case, State Lead Agencies (SLA), which are responsible for enforcing FIFRA, are 

not included in the notification requirements. SLAs can respond to reports of incidents in a 

timely manner and are experienced in conducting joint investigations with state and/or federal 

wildlife agencies. To prevent the loss of critical evidence due to delays, there should be an option 

for a “finder” to also report to a SLA, or local fish and wildlife agency. 

Term and Condition 2.b EPA shall report to NMFS Office of Protected Resources any 

incidents regarding diflubenzuron, fenbutatin oxide, or propargite effects on aquatic ecosystems 

added to its incident database that EPA has classified as "probable" or "highly probable". 

While EPA will work with NMFS to develop more efficient methods for reporting incident 

information in a routine manner, EPA would like to better understand how NMFS intends to 
14 

utilize this information so we can optimize our reporting for their needs.Conservation 

Recommendations (pgs. 720-721) 

 

Element (1) recommends that mixture toxicity analysis be conducted in screening level and 

endangered species biological evaluations. This topic was referred to the National Research 

Council (NRC) of the National Academy of Science (NAS). According to the conclusions in the 

NAS 2013 report “Assessing Risks to Endangered and Threatened Species from Pesticides” 

(page 97): 

 “A quantitative mixture risk assessment requires extensive data, including data on the 

identity, concentration, and toxicity of mixture components. Challenges in assessing risk 

to listed species from pesticide-containing mixtures arise largely because of the lack of 

such data and the lack of understanding of the potential for interactions among mixture 

components.” 

 “In the absence of such quantitative data, the possible contribution of specific mixture 

components to the toxicity of a pesticide active ingredient cannot be incorporated into a 

quantitative risk assessment. However, the risk assessor should describe the possible 

effects of mixture components on the risk estimate to the decision-maker.” 

As the type of data identified in the NAS response is usually not available when EPA conducts a 

screening-level assessment, analysis of mixture toxicity is not generally conducted. However, 

EPA will continue to evaluate formulated product toxicity data, when submitted, to determine if 

observed toxic effects may be attributed to the active ingredient alone. EPA recommends that 

NMFS revise Element (1) in the final BiOp to integrate the approaches that are developed as part 

of the interagency process underway to implement the NAS recommendations relative to mixture 

toxicity analysis. 

Element (2) recommends that EPA develop models to estimate pesticide concentrations in 

floodplain habitats. Models currently available to EPA are capable of simulating processes in a 

wide range of aquatic habitats including floodplain habitats of concern to NMFS. However, in 

order to make use of these modeling tools for simulating floodplain habitats, the geometry and 

hydrology of these systems need to be defined in a way that can be used to develop site-specific 

scenarios for the models. Given the wide range of floodplain habitat sizes and shapes used by 

Pacific salmonids, it is currently possible to assess only a small fraction of these environments, 

given the nature of current assessment tools. EPA has previously discussed the nature of these 

environments with NMFS and looks forward to further discussion on the characteristics of these 

waterbodies that would enable development of scenarios for floodplain habitats. Similar to the 

recommendation noted under Element (1) above, EPA recommends that NMFS revise Element 

(2) in the final BiOp to integrate the approaches that are developed as part of the interagency 

process underway to implement the NAS recommendations relative to exposure modeling. 

Element (3) recommends that EPA develop models to estimate pesticide concentrations in 

aquatic habitats associated with nonagricultural applications, particularly in residential and 

industrial environments. EPA has developed scenarios to employ the Tier II aquatic model 
15 

currently being used (e.g., PRZM/EXAMS) for residential and impervious surfaces and 

considers the use of these scenarios adequate for assessing runoff from these areas. 

Element (4) recommends that EPA work with other appropriate federal agencies to determine 

efficacy of riparian area management methods in reducing pesticide loading from authorized 

uses especially the types of vegetation and width of riparian areas needed. As discussed in the 

RPA comments above, while EPA concurs that the use of riparian areas has the potential to 

reduce pesticide loading via runoff and spray drift, the effects of riparian areas are pesticidespecific, site-specific, and temporally-specific, and EPA does not currently have the means to 

evaluate their effectiveness. EPA supports collaborative efforts with NMFS and USDA to 

identify methods for protecting endangered species that also minimize impacts to grower 

operations. 

As you are aware, EPA makes draft BiOps related to pesticide actions available through the EPA 

website5

 and a public docket6 for purposes of obtaining input on any draft RPAs, RPMs, terms 

and conditions, as well as provide an opportunity to propose alternate risk reduction measures 

that accomplish the same protection goals but may be easier/less costly to implement. As 

previously noted, these comments are available at: http://www.regulations.gov/#!docketBrowser;

rpp=25;so=DESC;sb=postedDate;po=0;dct=PS;D=EPA-HQ-OPP-2008-0654. EPA has made 

clear that any comments on other aspects of the draft BiOp submitted to EPA will be provided to 

NMFS for consideration during development of the final BiOp. EPA requests that you consider 

the comments EPA has received in the public docket related to this Draft BiOp. This would 

include all comments with a posting date since May 2, 2013 (the date on which EPA posted the 

Draft BiOp to the Docket). 

EPA believes that public transparency and accountability are core values for our agencies. EPA 

recommends that NMFS prepare a document for inclusion in the administrative record that 

addresses how comments were considered and, if appropriate, how the final BiOp will be 

modified to address the comments. EPA anticipates working with NMFS to finalize this BiOp 

and appropriate RPMs. 

Thank you for providing the draft BiOp for EPA's review and comment. EPA appreciates the 

methodological improvements NMFS has made relative to previous BiOps and believes there are 

areas that would benefit from further scientific review, discussion and continued cooperation 

between EPA and NMFS. 

 

5 http://www.epa.gov/oppfead1/endanger

6 http://www.regulations.gov/search/Regslhome.html#docketDetail?R=EPA-HQ-OPP-2008-0654
Please do not hesitate to contact me if you have any questions regarding our comments. 

Sincerely, 

Steven Bradbury, Ph.D., Director 

Office of Pesticide Programs 

cc: Jim Jones 

Sarah Bittleman 

Bill Jordan 

Donald Brady 

Richard Keigwin 

Helen Golde 

Anita Pease 

Cathrine Eiden 

Mark Dyn~r 

Melissa Grable 

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