Final Report:

Survey & Effectiveness of Pesticide Application Equipment Cleanout

Methods

2012-2013 HICAHS Pilot Grant

Co-Principal Investigators: Cynthia (Thia) Walker Colorado State University Department of Bioagricultural Sciences & Pest Management 1177 Campus Delivery Fort Collins, CO 80523 (970) 491-6027

Dr. Delphine Farmer Colorado State University Department of Chemistry 1872 Campus Delivery Fort Collins, CO 80523 (970) 491-0624

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Table of Contents Introduction ...................................................................................................................................... 2

Part 1 – Cleanout Survey ............................................................................................................... 2-22

Methods of Data Collection ............................................................................................................. 2

Results and Discussion ..................................................................................................................... 3

Part 2 – Cleanout Samples ........................................................................................................... 22-52

Methods of Sample Collection and Analysis .................................................................................. 22

Results and Discussion ................................................................................................................... 32

Summary ......................................................................................................................................... 54

Part 1: Cleanout Survey ................................................................................................................. 54

Part 2: Cleanout Samples ............................................................................................................... 54

Activities, Products and Future Directions.................................................................................... 55-56

Oral Presentations ......................................................................................................................... 55

Products ......................................................................................................................................... 56

Future Directions ........................................................................................................................... 56

References ....................................................................................................................................... 57

Appendix .................................................................................................................................... 58-88

PowerPoint Presentation Soliciting Survey Volunteers ................................................................. 59

Survey of Pesticide Application Equipment Cleanout ................................................................... 68

Survey for Contact Information for Research Study ...................................................................... 77

Information Survey for Submitting with Samples .......................................................................... 81

Methodology for LC-ESI-MS/MS quantitation techniques ............................................................ 86

Supplemental Information on LC-MS/MS system ........................................................................ 87

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Introduction

A number of problems arise each year from pesticide residues remaining in the pesticide application sprayer from previous applications. It may pose a safety issue for the applicator, might affect workers in the field under Worker Protection Standard, cost employers due to compensation to the injured party, or even result in the employee losing their job. Of these possible consequences, the most important are the risk to the applicator and the risk to field workers. This project was designed as a two part study; the first part was designed to survey licensed pesticide applicators to determine the factors that limit sprayer cleanout and procedures individual applicators use to clean the application sprayer. A paper survey was distributed to both Colorado licensed private and commercial applicators attending licensing recertification workshops.

The second part of the study was to analyze the effectiveness of individual applicator cleanout procedures by recruiting Colorado licensed pesticide applicators as volunteers, providing them with personal protective equipment for use while collecting samples during stages of their normal pesticide application equipment cleanout procedure, and analyzing the collected samples for pesticide residues. Participants will be provided with their individual as well as grouped results of efficacy of their tank cleanout procedures. Identities of participants in the sprayer cleanout sampling will remain anonymous when reporting results. The results of this study will be used to develop an Extension publication on effective methods for pesticide application equipment cleanout, will be presented to licensed applicators at recertification workshops during 2013-2014, and was presented at the National Pesticide Applicator Certification and Training (PACT) Workshop in Minneapolis, Minnesota in August 2013. It will also be presented at The Pesticide Stewardship Alliance Conference in February 2014 (http://tspalliance.org)

Part 1: Survey - Methods of data collection

Equipment Cleanout Survey & Contact Survey A Pesticide Application Equipment Cleanout survey was developed to determine demographics of the applicator responding, the design of the sprayer used by the applicator, what factors limit the applicator’s ability to clean the sprayer, at what point the sprayer is cleaned, and the procedure used by the applicator to clean the sprayer. A copy of the survey is provided in the Appendix. The survey was approved by Colorado State University’s Institutional Review Board (IRB).

The Pesticide Application Equipment Cleanout survey was distributed at Pest Management Workshops which are attended by licensed applicators seeking recertification continuing education credits. In Colorado, Pesticide Applicator licenses are valid for a three year period.

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Sometime during that period, applicators must attend recertification workshops approved by the Colorado Department of Agriculture Pesticide Program (CDA-PP) or must retest for certification. As a result, most applicators choose to attend recertification workshops.

To minimize the sampling bias, the research study was explained to applicators attending the CEC who were then asked to answer 3 demographic questions. Turning Point Audience Response System (Turning Technologies) was used to collect applicator responses. A copy of the presentation and the accompanying script are included in the Appendix. At the conclusion of the presentation, applicators were asked to voluntarily complete the Equipment Cleanout survey. Responses from completed Pesticide Application Equipment Cleanout surveys were entered into SurveyMonkey (www.surveymonkey.com) to compile the data. The following workshops were used for survey distribution and provided exposure to over 1100 licensed applicators:

Colorado Agricultural Aviation Association Rocky Mountain Regional Turfgrass Association Conference Rocky Mountain Agribusiness Association Winter Meeting ProGreen Expo Colorado Association of Lawncare Professionals TriRiver Area Pest Management Workshop And Private Applicator Recertification Workshops in Lamar, Cheyenne Wells, Ordway, Sterling, Brush, Holyoke, Akron, and Brighton. Part 1: Survey - Results and Discussion

Demographic Survey conducted at Recertification Workshops During the presentation at the recertification workshops in which participants were asked to voluntarily complete the surveys, all attendees were asked to respond to three demographic questions. These questions were intended to reduce sampling bias by demonstrating some of the characteristics of applicators attending the workshops. These characteristics can then be compared to the applicators that responded to the survey. The results of these responses are summarized in Chart 1. Although not every person responded to each question, 1102 applicators participated in the demographic survey.

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The results indicate that the majority of the applicators (60.3%) in the workshops were licensed as Commercial applicators, 28% of the applicators were licensed Private applicators, and 11.5% were not licensed. The individuals that are not licensed are typically working as trained technicians under a licensed person, or have not yet taken the exams for licensure.

There was a favorable cross section of applicators that make applications in both urban and rural environments as almost 50% make applications in farm/rural locations and 50% make applications in town/city/suburb locations.

Finally, the majority of the applicators (79%) have more than 3 years of experience while almost 13% had 1-3 years of experience and 8% had less than 1 year experience making pesticide applications.

Completed Cleanout Surveys Voluntarily Submitted by Applicators

The information that was collected by the cleanout surveys provides valuable insight into the experience of applicators, attitudes about cleaning equipment, challenges cleaning equipment, and types of equipment used. This information will be used by pesticide safety educators to

Chart 1. Responses from all applicators attending recertification workshops December 2012- April 2013.

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understand the practices and provide information to focus on training points to improve equipment cleaning and also provide information for discussion in trainings.

Demographic Information regarding respondents

Of the 1102 applicators that were present in the workshops and responded to the demographic questions, 613 returned the equipment cleanout surveys, representing a 55.6% response rate. Of those responding, 72% indicated they were licensed as Private applicators and 71% indicated that they hold a Commercial applicator license. It is not unusual for Commercial applicators to also hold a Private applicator license so they can make applications to their own property. This may have skewed the ratio of commercial and private applicators responding compared to the demographics obtained at the recertification workshops. Private applicators indicated that most of the applications made were made for weed control, followed by insect control (Chart 2). Fewer private applicators make applications for plant disease control and right-of-way. This indicates that majority of the pesticides used by private applicators are herbicides.

Chart 2. Types of applications made by Private applicators.

Commercial applicators indicated that most of the applications made were made for Ag weed control, Turf/Ornamental Weed control, and right-of way (Chart 3). Fewer Commercial applicators make applications for plant disease and insect control. This indicates that majority of the pesticides used by commercial applicators are herbicides.

94%

58%

40%

36%

Private Applicators (n=413) Weed Control

Insect Control

Plant DiseaseControlROW

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Chart 3. Types of applications made by Commercial applicators.

Survey results show that the majority of all applicators (84%) have more than 3 years of experience making pesticide applications, approximately 12% have 1 to 3 years of experience, and approximately 4% had less than 1 year experience. Compared to the demographic survey conducted at the workshops, this indicates that slightly more of the experienced applicators chose to complete the survey and fewer inexperienced applicators chose not to complete the survey (Chart 4). This suggests that the respondents should have ample knowledge about making applications as well as maintaining and cleaning application equipment.

Chart 4. Years of experience making pesticide applications for all survey respondents.

46%

46%

40%

30% 30%

28%

Commercial Applicators (n=433)

Ag Weed

Turf/Ornamental Weed

ROW

Ag Insect

Rangeland

OrnamentalInsect/Plant Disease

4% 12%

84%

Years of Experience (n=584)

Less than 1year1-3 years

More than3 years

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When respondents were asked to characterize their position, and allowed to choose all that apply, the majority indicated that they were the applicator and/or manager (Chart 5). Respondents also included individuals who mix/load pesticides and mechanics.

Chart 5. Position of Survey Respondent

Ninety-five percent (95%) of the respondents indicated that the applicator is the one who routinely cleans the application sprayers, including tanks, while 19% indicated that the mixer/loader routinely cleans the equipment (n=608).

Opinions of respondents relating to application equipment cleanout

When asked how important is cleaning their application spray tank to their operation, 71% indicated it was VERY IMPORTANT, while 27% said that it was SOMEWHAT IMPORTANT. Less than 2% indicated that it was NOT IMPORTANT AT ALL. The applicators in the latter group are likely to be those that use dedicated sprayers for individual products they use during the spray season and do not clean the sprayers until the end of the season.

Applicators were also asked their opinions about what factors were ‘VERY IMPORTANT, MODERATELY IMPORTANT, or NOT IMPORTANT AT ALL’, regarding cleaning their application equipment.

The majority found the following ‘VERY IMPORTANT’:

No suitable place to clean sprayer – 47% (n=600)

Limited availability of clean water – 46% (n=600)

Limited place to put rinsates during cleaning – 50% (n=596)

61%

76%

42%

24%

Position of Survey Respondent (n=608)

ManagerApplicatorMixer/LoaderMechanic

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These factors present challenges that many applicators must solve and can serve as important training points during recertification workshops. It is important to have a proper place to clean the sprayer where rinsate will not contaminate water supplies, streams, or where puddles will not be accessible to children, pets, or other animals. If applicators cannot find a suitable location, they must collect the rinsate and use it as a diluent for future pesticide mixtures. However, for it to be used legally as a diluent, it must meet certain conditions: if it is labeled on the site, if the amount of pesticide in the rinsate plus the amount of pesticide in the new mixture does not exceed labeled rate for the site, and if the rinsate is the same or compatible with the pesticide in the new mixture. If these conditions cannot be met, the rinsate can be collected and disposed of as hazardous waste. Survey respondents indicated that 71% apply the rinsates to a labeled application site while only 9% store it for future use. Another 23% indicate that they “pull the plug and let it drain” which we assume suggests they collect it at the mixing/loading pad and dispose of it as hazardous waste. Another challenge for applicators is to have a clean water source for rinsing. The best solution to rinsate disposal is to apply on a labeled site, however, it means that the applicator may have to carry additional water to the site for cleaning. The survey results show mixed results as to where spray application equipment is cleaned. Pesticide safety educators continue to emphasize that the first rinsate should be applied to the application site as it is likely to contain higher levels of residues than the subsequent rinses. Chart 6 shows the frequency with which respondents clean the sprayer at the application site. Chart 6. Frequency that applicators clean equipment at the application site.

38%

25%

37%

Clean at the application site (n=584)

Most times

Occassionally

Never

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Applicators sometimes choose to clean their equipment at the facility where the sprayer is stored. Chart 7 shows the frequency that respondents follow this practice. A large number of respondents indicated they do their cleanout where they store their equipment and pesticide safety educators must emphasize the proper disposal or reuse of rinsates when this is the location. Additionally, 2% of the applicators responded that they clean their equipment at the local car wash. Pesticide safety educators must emphasize that this is not a suitable site as the rinsates are directly disposed of into a municipal waste water system. Chart 7. Frequency that applicators clean equipment where the sprayer is stored.

Finally, it is difficult to find a suitable place to dispose of rinsate. As mentioned above, the best possible place to dispose of rinsate is to apply on a labeled site. Some recommendations for cleaning application equipment suggest filling the tank 1/3 full of water, spraying it out, and repeating that two additional times. That might seem reasonable with small tanks, but if that procedure is used on very large tanks, it can generate a large quantity of rinsate and complicate their disposal. For example, if the application equipment has a 1000 gallon tank, and it is filled 3 times with 300 gallons each time, that equates to 900 gallon of rinsate generated! Of the respondents, 36% indicated that they fill their spray tank with less than 1/3 full when cleaning while 36% indicated that they fill their tank 1/3 to 1/2 full when cleaning. The remaining applicators either fill more than half full or fill it completely full. These latter applicators represent applicators that have tanks 200 gallons or less and likely have less concern about quantities of rinsate disposal.

53% 29%

18%

Clean where the sprayer is stored (n=597)

Most times

Occassionally

Never

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The majority of respondents found the following ‘SOMEWHAT IMPORTANT’:

Difficulty in thoroughly rinsing sprayer tank – 40% (n=592)

This reflects applicators that have larger tanks (above 500 gallons) which can be more difficult to clean because it is difficult to reach all areas of the tank without a built-in rinsing nozzle or the use of a separate rinsing nozzle. Of the applicators responding to the survey, only 24% had a built-in rinsing system. Of those, 62% indicated that they did NOT rely solely on that system to clean their tank.

The majority of applicators also found the following ‘NOT IMPORTANT’:

Time Consuming – 43% (n=596)

Too much ‘downtime’ for equipment – 50% (n=593)

Cost of tank cleaning additives – 59% (n=598)

It is encouraging that a large number of the applicators do not consider the amount of time it takes to clean their equipment “too time consuming”. Only 18% considered this to be a VERY IMPORTANT factor in cleaning their equipment. The amount of time spent on the tank cleaning procedure is shown in Chart 8. The majority of the respondents indicated that it take 30 minutes to 1 hour to complete their cleaning procedure.

Chart 8. Time spent on cleaning procedure

30%

53%

18%

Time spent on cleaning procedure (n=591)

< 30 minutes

30 min-1 hour

> 1 hour

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And 50% of the respondents were not concerned with the amount of ‘downtime’ when cleaning the equipment. This is important as some of the cleaning procedures for certain pesticide products recommend adding a tank cleaner such as ammonia and allowing it to stand overnight before rinsing. And the majority of respondents were not concerned with the cost of tank cleaning additives. Provided they select the proper additive for their pesticide product, the cost can be much lower than compensating a client or losing a crop and safety educators should remind applicators of this mindset.

Information about the application equipment

Respondents were asked if, at any time in the last 5 years, they ever experienced left over residues in the spray tank causing symptoms to off-target plants. While 84% indicated they did not, 16% have observed this problem (n=608). Seventeen percent (17%) of commercial applicators indicated that they have observed symptoms in off-target plants while only 15% of private applicators admit they have observed this. Picture 1 is an example of pesticide residues from a previous application affecting a crop in a subsequent application. Typically, in this situation, the area where the application begins is affected and as the contaminants are sprayed out, the crop damage declines.

Picture 1. Damage to sugarbeet crop from residues in application sprayer.

Some of the difficulty that applicators face in cleaning their sprayer is due to the equipment itself. While 46.5% of the respondents have sprayers with tank capacities up to 200 gallons, some applicators have tanks that hold over 1000 gallons (Chart 9). As the tank capacity increases, the tanks become more difficult to clean as it is challenging to reach all areas of the inside of the tank. As previously mentioned, only 24% of the respondents report having a built-in tank rinsing system. Those who do not, should consider using a separate tank rinsing nozzle if

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they have a large tank. These are available from several manufacturers but applicators must select a nozzle based on the size of the spray tank to be cleaned.

Chart 9. Tank capacities of sprayers

The majority of respondents indicate that their spray tank is constructed of polyethylene which, in general, is more difficult to clean than stainless steel (Chart 10). However, stainless steel and aluminum tanks can become corroded by some pesticides and fertilizers if not cleaned after use. If the tank does not have adequate agitation, dry-flowable and wettable powder formulations can settle and accumulate in the bottom of spray tanks, making cleaning more difficult regardless of the composition.

46%

30%

15%

9%

Tank capacity of sprayers (n=602)

up to 200 gal

201-500 gal

501-1000 gal

1001-1500 gal

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Chart 10. Composition of spray tanks

Most survey respondents indicated that they have tanks which are horizontal in shape, followed by vertical tanks (Chart 11). Some indicated that they have tanks on their aircraft, either saddle tanks on a helicopter or a tank built into the fuselage of the aircraft. Horizontal tanks are more challenging to clean as the upper surfaces are difficult to reach as are areas around tank baffles. Tanks built into aircraft fuselages today typically hold 400 to 800 gallons and can be difficult to clean as they may still retain 5 or more gallons when ‘empty’. Saddle tanks range from 90 gallons to 230 gallons and are mounted on the contour of the body on both sides. Due to their smaller size, these are likely easier to clean.

Chart 11. Shape of spray tank.

68% 18%

14%

Composition of spray tank (n=610)

Polyethylene

Stainless Steel

Fiberglass

79%

19%

5% Shape of spray tank (n=605)

Horizontal

Vertical

Built in fuselageor saddle tanks

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The majority of the sprayers have chemical resistant hoses running from the tank to the spray boom (67%, n=607), followed by rubber hoses (27%). Respondents indicated that, for most sprayers, the boom line is constructed from chemical resistant hoses, followed by stainless steel pipe, and rubber hoses. It is important that applicators check hoses and boom lines for cracks as pesticide residues can collect there and should be replaced to reduce the risk of this happening. Other respondents indicated that they have a boomless sprayer (Chart 12).

Chart 12. Material boom constructed from

Pesticide residues can collect in ends of booms which can be released during subsequent applications. This design flaw occurs in both ground application equipment and aerial application equipment. Many applicators have modified boom ends after purchase so that they have the ability to clean them, as shown in Picture 2.

40%

12%

17%

12%

7%

Material boom constructed from (n=578)

Chemical resistant

Stainless steel

Rubber

Polyethylene

Other

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Picture 2. Ends of booms (circled) can accumulate pesticide residues if not cleaned. This boom was modified after purchase.

Information about procedures used to clean application equipment

Respondents were asked how often they clean their application equipment, and were asked to choose all that apply. The results are shown in Chart 13. The majority of applicators (59%) clean their application equipment when switching type of pesticide. This would primarily be when switching from a herbicide to an insecticide or fungicide in effort to avoid phytotoxicity to the crop. Some applicators (31%) clean when switching sites (crops, turf, ornamental, etc). These applicators don’t worry about whether they are spraying a herbicide, fungicide, or insecticide as long as it is labeled for the site (for example, corn). If they switch sites (for example, from corn to sugar beets), they would clean their equipment. A small portion of applicators (22%) clean the sprayer at the end of each day’s use. Applicators should be encouraged to mix only the amount required for the day and to end with an empty tank. If the same material will be used the next day, rinsing with water may be sufficient. Otherwise, more comprehensive cleaning may be required. Applicators should be reminded that it is never a good idea to allow pesticide spray solutions to sit overnight as some pesticides will continue to degrade and residues may dry on the tank interior. Also, some pesticides may cause the equipment to deteriorate if left in the tank for extended periods of time. Some pesticide solutions also create a paste-like substance in the tank and accumulation of this material can be avoided by frequent cleaning.

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Chart 13. Frequency of sprayer cleaning.

Respondents were asked which tasks they routinely do when cleaning the sprayer and were allowed to choose all that apply. Chart 14 indicates how they clean the outside of the sprayer and the tank, while Chart 15 indicates what other components of the sprayer they clean. A large majority of the respondents (78%) clean both the outside and the inside of the sprayer while 30% clean only the inside tank. A few (17%) clean only the outside of the sprayer. Pesticide safety educators should remind applicators that it is important to clean BOTH the outside of the sprayer as well as the inside of the tank, especially if concentrated chemicals have been spilled during mixing/loading. But cleaning the outside of the sprayer is also important before working on, or allowing others to work on, any of the sprayer components.

22%

31%

59%

37%

How often sprayer is cleaned (n=587)

At the end of eachdayWhen switchingsitesWhen switchingtype of pesticideAt the end ofseason

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Chart 14. Parts of sprayer cleaned

The majority of respondents clean components on the sprayer as shown in Chart 15. Ninety percent (90%) of the respondents clean the sprayer hoses by flushing water through the system. However, only 55% of them clean out the end of the booms. This is likely due to the design of the boom and, as mentioned previously, many applicators have to modify their boom to accomplish this. Nozzles and screens are cleaned by 77% of the respondents and pesticide safety educators should remind applicators that these components are easily clogged with residues and contaminants which will alter application rates. Seventy-one percent (71%) clean filters on the spray system. It is important to clean these as contaminants frequently collect in these components (Picture 3).

17%

30% 78%

Parts of sprayer cleaned (n=592)

Clean outside ofsprayer only

Clean inside oftank only

Clean both outside& inside of sprayer

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Chart 15. Components cleaned on sprayer

Picture 3. As shown here, contaminants can collect in screens and filters in the sprayer system.

Most applicators use a 3 rinse system with a tank cleaner during the second rinse (Chart 16). About 1/3 of the respondents indicated that they just run water through the system to clean and some just rinse twice, using a tank cleaner at the second rinse. Still others indicate that they use other methods including triple rinse with just water or power washing followed by rinsing.

76%

71% 90%

55%

Components cleaned on sprayer (n=592) Clean nozzles &

screensClean filters

Clean hoses

Clean out end ofbooms

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Chart 16. Procedure typically used to clean sprayer

Respondents were also asked if they wore personal protective equipment (PPE) when cleaning sprayers. Although 87% indicated that they did wear PPE, 13% do not. This represents an important area for pesticide safety educators to alert applicators that PPE is necessary when cleaning equipment to protect themselves from not only the spray solution, but to protect themselves from some of the chemicals used to clean the equipment.

When asked about what they routinely add when cleaning the inside of the spray tank, the majority of respondents indicated only water. However, others used commercial tank cleaners, ammonia, or chlorine bleach (Chart 17). Only one respondent indicated that they use fuel oil or kerosene to clean the sprayer.

34%

14% 50%

6% Procedure used (n=599)

Just waterthrough system2 rinses with tankcleaner3 rinses with tankcleanerOther

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Chart 17. Additives used when cleaning inside of sprayer.

Respondents were asked to indicate which commercial tank cleaners they routinely used. Of the 157 respondents, the majority indicated they use Wipe-Out® (Helena Chemical Company) followed by Cornbelt® Tank and Equipment Cleaner. Chart 18 indicates the products and percentages of the 157 respondents naming a specific tank cleaner.

Chart 18. Most commonly used tank cleaners when named by respondents.

Pesticide safety educators should instruct applicators to refer to equipment cleaning instructions on pesticide labels when available. However, few labels provide specific instructions on cleaning application equipment so applicators need to be provided with guidelines on which products to use for specific pesticides, and the precautions they must take

48%

40%

15% 10%

Additives used for cleaning inside sprayer (n=591)

Water only

Commercial tankcleanerAmmonia

chlorine

22%

11% 8%

7%

5% 4%

Most commonly used tank cleaners (n=157)

Wipe-OutCornbeltAll ClearPro TankK-KleanDish soap

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when using them. Commercial tank cleaners can be used to remove some oil-and water-soluble herbicides as they usually raise the pH of the solution and act as detergents. The choice of tank cleaner is often decided by the owner of the operation or the manager and applicators may not have the freedom to choose otherwise.

Wipe-Out® is a combination of nonionic and ionic surfactants plus ammonia (1.5-3%) which carries a WARNING signal word due to its corrosiveness and ability to cause eye and skin irritation. Cornbelt® Tank and Equipment Cleaner (Van Diest Supply Co.) also contains 1.5-3% ammonia along with complex phosphates, sodium hydroxide, sodium carbonate, monocyclic terpenes and nonionic surfactants. It carries a CAUTION signal word due to its ability to irritate eyes and skin. All Clear® (Loveland Products, Inc) is promoted as a non-ammonia cleaner containing sodium dodecylbenzenesulfonate and 2-aminoethanol. It carries a WARNING signal word because it is a eye and skin irritant. Pro Tank® (Winfield) is a proprietary blend of phosphate and carbonate salts, sequestering agents, surfactants and solvents. It carries a DANGER signal word because it can cause severe burns to eyes. K-Klean™ (Kalo Inc.) contains ‘cleaning agents in a proprietary transparent emulsion’ containing sodium xylene sulfonate and sodium metasilicate. It carries a CAUTION signal word.

Although all these products have signal words, not all of them have labels containing PRECAUTIONARY STATEMENTS for PPE. Sometimes, applicators would have to refer to the Safety Data Sheet (SDS) for protective equipment. Pesticide safety educators train applicators to refer to the PPE requirements on the pesticide label and NOT to the Safety Data Sheet so recommending they refer to the SDS when using tank cleaners is contrary to what they have been told about requirements when using pesticides. In general, applicators should refer to the PPE requirements for the pesticide products in the tank and the PPE for the tank cleaner, and use the most restrictive requirements for protection. They should also consider wearing a chemical resistant apron and goggles, even if not required.

It’s difficult for applicators to determine the best product to use due to the number of cleaners with a variety of ingredients. While the best source of information for cleaning sprayers is the pesticide label. However, many generic formulations do not offer any information. Pesticide educators need to inform applicators when to use different chemicals based on the pesticides they are trying to clean out of the sprayer. For example, a 1% household ammonia solution (1 quart to 25 gallons water) can be used to increase the pH of the solution which can increase the solubility of some pesticides, but it will not decompose or deactivate them. Chlorine bleach solutions can deactivate residues of many pesticides but it does not increase their solubility so it is not used as often. Additionally, chlorine bleach cannot be used in tanks which had ammonia fertilizers as this will produce toxic chlorine gas. Oil-based esters and emulsifiable concentrate formulations are typically more difficult to remove from spray tanks so a general

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guideline is to clean with a 1% solution of kerosene or diesel fuel (1.5 cups kerosene plus 1 TBSP powdered detergent in 2.5 gallons water added to 25 gallons) followed by a second rinse of 1% ammonia, followed by a water rinse. Even household detergents can be used to remove some water-soluble liquids or wettable powders. Although respondents indicated they used liquid soap, most recommendations suggest using dry household detergents (2 pounds to 30-40 gallons water). Trisodium phosphate (TSP) is another example of a household detergent that can be used at a ratio of 1 cup TSP to 25 gallons water. Applicators should also be made aware that crop oils or nitrogen solutions can release herbicide residues remaining in spray equipment. (Bretthauer, 2006; Duncan, 2011; Wilson, et.al, 2000)

When respondents were asked if they winterize their application equipment, 90% of them indicated that they do while 10% do not (n=597). Winterizing application equipment is important to properly maintain equipment. However, as automotive antifreeze is typically recommended to winterize after a final cleaning, applicators should be reminded to collect the antifreeze solution when running the mixture through the entire system and draining the fluid prior to the start of a new application season (Duncan, 2011).

PART 2: Methods of Sample Collection and Analysis

At the conclusion of the survey in Part 1, respondents were asked to consider participating in a research study on the effectiveness of their application sprayer cleanout. The last page of the Equipment Cleanout survey asked for volunteers interested in participating in Part 2 of the research project to complete the Contact Information: Pesticide Sprayer Tank Cleanout Research Study. This document is also included in the Appendix. If they chose to participate in the study, they were asked to provide their name, mailing address, and email contact information and information on what type of applicator license they hold. Of the interested parties, 91 applicators were selected to voluntarily participate in the study and reflected a combination of private/commercial applicators and aerial/ground applicators. However, only 46 of the sample boxes were returned for sample analysis, with an additional 5 boxes lost in transit.

The sampling participants were provided a box containing the following items:

• Personal Protective Equipment (Tyvek QC Chem Spray Suit with Hood, disposable boots, chemsplash googles, three sets of 15-ml nitrile gloves, chemical-resistant apron)

• 6 sampling jars (to collect spray solution from tank, water sample from water source used to clean, up to 3 tank rinses, and a sample of tank cleaner, if used)

• Pre-paid packing box to return samples to CSU Department of Chemistry • Paperwork to document pesticides in the tank, information about the equipment and

procedure they used to clean equipment (included in the Appendix)

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Pesticide standards were provided by the Colorado Department of Agriculture from the Environmental Protection Agency. Mobile phases were (A) water with 0.1% formic acid and (B) acetonitrile with 0.1% formic acid; all solvents are LCMS grade purchased from Fischer Scientific.

Three methods were used to analyze the data: (1) HPLC-UV analysis, (2) LC-UV-MS/MS analysis, and (3) a total ion detection method. These approaches are described below. Table 1 summarizes the detection techniques used in this study. The +/- under HPLC-MS/MS indicates the ESI polarity that was used for detection. Blanks indicate that quantification was not possible with the instrument. In addition, a Vernier conductivity probe was used to determine ion concentration in selected samples.

Table 1. Quantitation of a broad suite of pesticides through LC-UV and LC-MS/MS techniques.

Pesticide

HPLC-UV/VIS C8

HPLC-MS/MS C18

2,4-D

-

aminopyralid

-

atrazine Y

bifenthrin Y

chlorsulfuron

-

clethodim

+

clopyralid

-

dicamba

-

diflufenzopyr

diquat dibromide

diuron Y +

EPTC Y +

fluroxypyr

-

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glyphosate

hexaconazole y +

imazamox

+ -

imazapyr

+ -

Malathion

MCPA

Mecoprop

mecoprop-P

-

mesotrione

-

methamidophos

metsulfuron-methyl

+ -

Oryzalin Y -

pendimethalin Y

Picloram

-

Pinoxaden

+

Quinclorac

S-metolachlor Y +

sulfentrazone Y -

trifensulfuron-methyl

+ -

Triclopyr

-

Trifluralin Y

triflusulfuron-methyl Y -

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(1) HPLC-UV. While HPLC has been previously demonstrated for separation of aqueous pesticides, such separations typically use mass spectrometric detectors. However, UV/Vis detectors are less expensive and more common. We investigated HPLC-UV for quantitative analysis of aqueous pesticide concentrations. While 35 aqueous pesticides were investigated, quantitative separation was achieved for 11 pesticides, as summarized in Table 2.

HPLC separation

0

0.5

1

1.5

2

2.5

190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340

ABSO

RBAN

CE U

NIT

S

WAVELENGTH (NM)

2,4-D AminopyralidAtrazine BifenthrinChlorsulfuron ClethodimClopyralid DicambaDiflufenzopyr Diquat DibromideDiuron EPTCFluroxypyr GlyphosateHexaconazole imazamoximazapyr MalathionMCPA Mecoprop-PMesotrione Methamidophos

Figure 1. Absorbance in the UV-Visible range for a select suite of pesticide standards

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An HPLC-UV (Thermo Scientific Dionex Ultimate 3000) was equipped with a reversed-phase C8 analytical column (Aglient Zorbax SB). We investigated separation along a gradient of water (HPLC grade, mobile phase A) and acetonitrile (HPLC grade, mobile phase B). Prior to experiments, the column was flushed with solvent (80% water, 20% acetonitrile, 0.6 mL min-1) for one hour. Initial separation was based on methods described in Rajski et al. Separation of aqueous pesticide mixtures was optimized to a flow rate of 0.9 mL min-1 and a series of linear mobile phase gradients with the first gradient spanning 15 minutes shifting from 100% water to 95% water / 5% acetonitrile, a second gradient spanning five minutes from 5% acetonitrile to 50% acetonitrile, and a 3rd gradient spanning 17.5 minutes to 100% acetonitrile. The gradient was held at 100% acetonitrile for 1.5 minutes before returning to initial conditions. The total run time was 43 minutes. Sample injection volume was 50 µL. The column was maintained at 60°C. Blank runs included both water and acetonitrile samples. Based on UV-Vis spectra obtained for the full suite of pesticides under study (Figure 1), the detector was set to 200 nm.

A sample LC-UV chromatogram is shown in Figure 2. Distinct separated peaks were observed for selected pesticides (Figure 2), which resulted in calibration curves demonstrating adequate sensitivity.

Figure 2. Typical LC-UV chromatogram using an Agilent Zorbax C8 column wih gradient elution with an acetonitrile/water mix.

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Figure 3. Chromatograms for multiple pesticide standards of varying concentration demonstrate the LC-UV's potential for quantitative analysis

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Separation of atrazine and diuron was achieved by wavelength switching between 200 and 224 nm. By comparing the absorbance at two wavelengths and noting that atrazine and diuron have very different absorbances at these two wavelengths, we are able to quantify the two pesticides, despite overlapping retention times.

The HPLC-UV analysis allowed us to separate eleven pesticides with retention times (ts) between 20-35 min. Detection limits (S/N = 3) for the 11 pesticides ranged from 7 to 1014 ppb, and are summarized in Table 2. Allowable values are either EPA-MCL (regulated maximum contamination limit in drinking water) or USGS-Health Based Screening Levels (suggested maximum concentration in drinking water). Some limits were not available.

Table 2. Detection limits and sensitivity for pesticide quantitation by LC-UV.

(2) LC-UV-MS/MS. Calibration standard preparation is summarized in the Appendix. Standards and samples were analyzed on a Hewlett-Packard Agilent 1100 series high performance liquid chromatograph coupled to mass spectrometric detection (HPLC-UV-ESI-MS/MS) (California, USA) using a 0.45 µm filter and a Waters XBridge BEH C18 XP column (130 Å, 3.5 µm, 2.1 mm x 150 mm) (Ireland) (Part number 186003023 Lot No. 128B381711). UV absorption was detected at 200 nm. The tandem mass spectrometer settings were optimized using 10 µM to 25 µM pesticide standards in 1% acetonitrile and 99% water, and are summarized in the Appendix. Figure 4 shows pesticide calibration curves in ESI negative mode for pesticide mixed standards levels of L5 (10,000 ppb), L4.2 (6,000 ppb), L4.1 (3,000 ppb), L4 (1,000 ppb), L3.1 (500 ppb), L3 (100 ppb), and a 20% water/80% acetonitrile blank. The concentrated pesticide standards were made in acetonitrile and were diluted into water to the desired concentration. Table 3 includes

29 | P a g e

pesticide calibration curve line fit data, uncertainty, R2, detection limits, ion used for integration, and the integration time range. The blank standard deviation was calculated using the integration of six blanks.

Figure 4. Pesticide calibration curves for LC-MS/MS standards mixed in water.

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Table 3. Calibration curve parameters for pesticide quantitation by LC-MS/MS

Pesticide

ODR Slope,

M

(area/ppb)

Slope Relative

Uncertainty

(%)

R2

Blank Standard

Deviation, S

(area)

Limit of Detection, DL

3S/M

(ppb)

Integration

Ion

(m/z)

Integration

Range

(min)

2,4-D 4893.5 2.49% 0.9970 35159 21.55 219.4 11.54-13.00

aminopyralid 380.95 7.38% 0.9720 23557 185.5 205.1 1.96-3.11

chlorsulfuron 3753.8 6.77% 0.9766 14869 11.88 356.6 10.69-11.35

clethodim 23152 5.27% 0.9864 137002 17.75 358.7 14.81-19.48

clopyralid 894.56 2.93% 0.9958 193490 648.9 190.3 2.55-4.51

dicamba 4850.3 2.39% 0.9972 16683 10.32 219.3 8.91-9.80

fluroxypyr 2033.0 3.02% 0.9954 31619 46.66 253.4 8.56-9.68

imazamox 13119 0.63% 0.9998 11807 2.70 304.4 4.16-5.15

imazapyr 8081.6 1.45% 0.9990 18120 6.73 260.4 2.80-4.10

mecoprop-P, MCPP 9497.8 3.65% 0.9934 26054 8.23 213.5 12.98-14.10

mesotrione 9141.4 2.43% 0.9971 15624 5.13 338.5 9.53-10.30

metsulfuron-methyl 5417.6 7.07% 0.9744 44547 24.67 380.5 9.97-10.86

oryzalin 16691 5.84% 0.9834 47365 8.51 345.7 15.53-16.38

picloram 834.61 2.56% 0.9966 55887 200.9 239.2 2.76-4.60

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sulfentrazone 13942 2.87% 0.9959 28877 6.21 385.7 11.00-11.93

thifensulfuron-methyl

3547.9 7.16% 0.9738 8060 6.82 386.5 9.45-10.23

triclopyr 3937.1 1.93% 0.9982 26078 19.87 254.4 12.32-13.21

triflusulfuron-methyl 17989 10.62% 0.9453 78574 13.10 491.4 14.71-15.60

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Results

The full suite of samples received and analyzed at the time of this report are summarized in Table 4. Table 5 includes pesticide concentration (ppb) for each sample jar as determined by LC-MS/MS, as well as additional information on cleaners and percent removal for each rinse cycle. We note that a few late-arriving samples are in the process of being analyzed. The LC-UV data are summarized in Figs 5 and 6.

Figure 5. Pendamethalin in Sample 4 as determined by LC-UV.

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Figure 6. Atrazine in Sample 82 as determined by LC-UV analysis.

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Table 4. Samples received and analyzed from the HICAHS project, including the last three pesticides used in the tank (product name, EPA registration number).

Sample Date Response Text Pesticides

4 Jul 16, 2013 10:24 PM

Hardball - 5905-549

Pendulum - 241-341

Confront - 62719-92 2,4-D pendimethalin triclopyr clopyralid

17 Jul 16, 2013 10:03 PM

Perspective EPA 352-846 Glyphosate 4 Pro EPA 72112-4 Speedzone - EPA2217-833 Chlorsulfuron glyphosate dicamba

mecoprop-p 2,4-d

24* Jul 16, 2013 9:56 PM

Touchdown 100-1169

Halex 100-1282

Atrazine - 9779-225

Clarity - 7969-137

Quadris 100-1098 Glyphosate S-Metolachlor glyphosate

mesotrione atrazine dicamba

42 Jul 3, 2013 9:27 PM

Milestone 62719-519 Torodon - 62719-6 Latigo - 5905-564 aminopyralid picloram 2,4-D dicamba

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34 Jul 3, 2013 9:19 PM

Amine 4 2,4-D 34704-120

Makaze 34704-MT-001

Strut 34704-1043 2,4-D Glyphosate dicamba

82 Jul 3, 2013 9:16 PM

Durango 62719-517 Status 7969-242 Atrazine 4L 11773-1 bifenthrin glyphosate atrazine dicamba diflufenzopyr

80 Jul 3, 2013 9:14 PM

Roundup 524-549

2,4-D 1381-102

RangeStar 42750-55 glyphosate 2,4-D dicamba

1 Jul 3, 2013 9:09 PM

Buccaneer Plus 524-454-55467

Status 7969-242

Zidua 7969-388 glyphosate dicamba diflufenzopyr

10 Jul 3, 2013 9:03 PM

Durango Glyphosate 62719-517

Detonate Dicamba 7969-137-55467

Dimethoate Dimethoate 34704-207 bifenthrin glyphosate dicamba

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31 Jul 3, 2013 8:41 PM

Makaze Gen "Glyphosate" Sterling Blue "Clarity" Activate glyphosate dicamba

12 Jul 3, 2013 8:38 PM

Dicamba 42750-40 RT3 524-544 Vida (pyraflufen-ethyl) 10163-314 Dicamba pyraflufen

36 Jul 3, 2013 8:35 PM

Ranger Pro 524-517

ProClipse 228-434

Triplet 228-4009 glyphosate 2,4-D Dicamba

81 Jul 3, 2013 8:33 PM

Intensity 34704-864

2,4-D LV4 1381-102

Roundup Powermax 524-549 Clethodim 2,4-D glyphosate

77

Latigo, NuCop, Approach 2,4-D

50

E-99 EPA 1381-195

Alligare MSM EPA 81927-7 Dicamba 4DMA EPS 83520-10 Crop Oil Concentrate CAL 5905-50085-AA

Cornerstone 5 Plus EPA 2,4-D

Metsulfuron- Methyl dicamba glyphosate

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42750-59-1381

Class Act NG CA 1381-50005-AA

9

Atrazine 4L EPA 33270-10

Huskie EPA 264-1023

WeedOne LV6 EPA 71368-11 Atrazine Pyrasulfotole 2,4-D

23

AMINE 2,4-D 48273-4-829

Rifle 34704-861 Act 90 (Surfactant) 2,4-D Dicamba

3

Mojave 70-EG #74477-9-81927

Cornbelt 4lb. Amine #11773-2

GlystarPlus #42750 Imazapyr Diuron 2,4-D Glyphosate

48

Plateau 241-365

Vista XRT 62719-586

Hardball 5905-549 Imazapic fluroxypyr 2,4-D

19

Escort 352-439 metsulfuron-methyl 2,4_D

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2,4-D (LV6) 71368-11

Brewer90 Exempt

47

Torndon22K - EPA62719-6 Hardball - EPA 5905-549 Induce - Surfactant picloram 2,4-D

43

Sureguard EPA 59639-120 Platoon EPA 228-145

Rodeo EPA 62719-324 2,4-D glyphosate

62

RECENT: Glystar Plus 42750-61

Outlaw 42750-68

PRIOR: Oberon 4SC 264-850 Glyphosate Dicamba 2,4-D

2

Battleship EPA #228-371-5905 Trimec992 EPA #2217-656

Mec Amine-D EPA# 34704-239 MCPA fluroxypyr Mecoprop 2,4-D dicamba

45

Dicamba

2,4-D

Buccaneer Plus Dicamba 2,4-D glyphosate

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79

August 14,2013

Roundup Power Max 524-549, 2,4-D&Dicamba RangeStar 42750-55 Dicamba 2,4-D glyphosate

53 August 14,2013

Karate Syngenta 100-1086, Gemstar Certis 70051-45， Brigade FMC 279-3313

Lambda-Cyhalothrin

virus (polyhedral occlusion bodies) bifenthrin

30

Grazon P & D #62719-182 Rifle #34704-861 Purestand #71368-38 picloram 2,4-D dicamba Metsulfuron-Methyl

39

Outlaw EPA# 5905-574 WeedDestroy AM-40 Amine Salt EPA# 228-145 2,4-D dicamba

6

August 20,2013

Dicamba Max 4 #83222-14 weedar 64 #71368-1 2,4-D dicamba

75 August 20,2013

Milestone 62719-519 Telar XP #352-654,

Vanquish 228-397, 2,4-D (cornbelt) #11773-2 aminopyralid

chlorsulfuron 2,4-D dicamba

87 30-Aug NA 2,4-D Glyphosate dicamba

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7 Sep.5

Rapid Fire #62719-566,

Latigo #5905-564,

Low Vol6 #34704-125 glyphosate 2,4-D dicamba

58 Sep.10

34704-120 Amine 4 2,4-D Weed killer;

62719-6 Tordon 22K 2,4-D picloram

46 Oct.7

speedzone #2217-833,

hardball #5905-549,

transline #62719-259 2,4-D mecoprop-p dicamba clopyralid

20 Oct.7

Weedmaster #71368-34, surflan A.S. #70506-44,

Razor Pro 228-366 NA (broken jars) Dicamba oryzalin Dicofol

64 Oct.8

Kocide #352-662,

Tanos #352-604,

Mancocide #352-690 copper hydroxide Famoxdone cymoxanil

59 Oct.8

Gly star #42750-61, Glystar/Dicamba 42750-209, Widematch #62719-512 Glyphosate dicamba clopyralid fluroxypyr

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5 Oct.8 Grazon P+D #62719-182 picloram 2,4D

67 Oct.8

Durango DMA #62719-556 , Atrazine 4L #1381-158, SNARPIN #769-278 Glyphosate atrazine

52 Oct.8

milestone 62719-519,

E-2 #228-442,

Telar 352-654 Aminopyralid Chlorsulfuron 2,4-D fluroxypyr dicamba

38 Oct.8

Tordon #62719-5,

2,4-D Amine #48273-4-829 Picloram 2,4-D

27 Oct.8

buccaneer #55467-9,

piper #63588-93-59639, perspective #352-846 glyphosate flumioxazin proxasulfone Chlorsulfuron Aminocyclopyrachlor

73 Oct.8

makaze yield pro #34704-1033, LI 700 #34704-50035, gunsmoke #34704-50077 glyphosate

phosphatidylcholine, methoxyacetic acid and alkyl polyoxyethylene ether

monocarbamide dihydrogen sulfate

alkylamine ethoxylate 1,2,3-trihydroxypropane

92(88) Oct.8 Amine 4 2,4-D 34704-120 2,4-D

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16 Oct.11

milestone #62719-537,

Talar 352-654,

Pendulum 241-341,

Rodeo 62719-324 aminopyralid chlorsulfuron

pendimethalin glyphosate

35 Oct.15

Matrix #352-556,

Telar XP #352-654,

Milestone #62719-519

rimsulfuron(CAS122931-48-0)

Chlorsulfuron aminopyralid

74 Oct.15

Habitat #241-426,

Rodeo #62719-324 imazapyr glyphosate

65 Oct.18

Reglone #100-1041,

Super Tin Group #70506-214, Bravo Ultrex #50534-201-100

diquat as dibromide

triphenyltin hydroxide chlorothalonil

66

Oct.18 (Jar not arrived, J6 last rinse)

Amine4 #71368-1-2935,

Matrix SG #352-768,

Eptain 7E #10163-283

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29 Nov.7

Dimension 2EW #62719-542, Speedzone+induce #2217-833, Trimec 992 +induce #2217-656 dithiopyr

carfentrazone-ethyl 2,4-D mecoprop-p dicamba

61 Nov.7

Tomahawk (5 pound generic round-up) #83222-21@40oz, E99(6-pound 2,4-D)-#1381-195@30oz Glyphosate 2,4-D

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Table 5. Final LC-MS/MS concentrations. * indicates that pesticide was detected but not listed as recently used. Italics: values below DL. We note that background water signals from jar 1 have not been subtracted from the signals of jars 2-5.

# Pesticides

Jar 1

Background

Water

(ppb)

Jar 2 Concentration (ppb)

Jar 3 Concentration (ppb)

Jar 4 Concentration (ppb)

Jar 5 Concentration (ppb)

Jar 6

Cleaner

(Y/N)

Number

of Rinses

Detection Limit, DL (ppb)

Final Rinse

Percent Removal

1 2.4-D* -2.46 41838.47 109.74 - - N 3 21.55 99.74%

1 dicamba -42.43 387566.53 443.02 - - N 3 10.32 99.89%

2 2,4-D -4.57 21384.28 166.20 160.95 21.57 N 3 21.55 99.90%

2 dicamba -38.05 1713.16 -1.64 -15.62 -30.47 N 3 10.32 101.78%

2 fluroxypyr -156.46 12587.72 -117.29 -101.91 -52.92 N 3 46.66 100.42%

2 mecoprop-p -272.91 7773.97 -265.03 -271.98 -267.69 N 3 8.23 103.44%

3 2,4-D -3.74 559533.33 44558.96 7081.27 - Y 2 21.55 98.73%

3 dicamba* -47.31 53044.50 2483.08 64.37 - Y 2 10.32 99.88%

3 Imazapyr 25.66 458794.81 18364.81 482.99 - Y 2 6.73 99.89%

4 2,4-D -8.30 447509.31 107735.21 62140.36 29207.86 Y 3 21.55 93.47%

4 clopyralid -125.24 872.63 1.42 -102.78 -131.05 Y 3 648.9 115.02%

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4 triclopyr -92.13 4825.99 74.69 38.37 -71.58 Y 3 19.87 101.48%

5 2,4-D N/D 5543.359

5 picloram N/D 3219.348

6 2,4-D 572867.62 69.9577 99.99%

6 dicamba - -20.6247

7 2,4-D 668394.16 1833.857 99.73%

7 dicamba 527163.79 579.7239 99.89%

8 2,4-D 26780.65 1997 3065.15 524.49

9 2,4-D 3.24 91569.41 7713.08 - - N 1 21.55 91.58%

10 dicamba 3.01 633470.59 69.54 32.06 -19.72 Y 3 10.32 100.00%

12 2.4-D* 79.63 41765.73 5460.19 2229.52 666.95 Y 3 21.55 98.40%

12 Dicamba -23.37 457717.62 32105.67 6204.63 987.09 Y 3 10.32 99.78%

16 aminopyralid N/D N/D

16 Chlorsulfuron N/D N/D

17 2,4-D -3.87 3754.11 316.34 368.98 106.52 N 3 21.55 97.16%

17 chlorsulfuron -182.58 191608.78 6403.30 333.69 -163.48 N 3 11.88 100.09%

17 dicamba -33.71 1163.24 15.46 10.83 -18.01 N 3 10.32 101.55%

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17 mecoprop-p -275.67 534.14 -170.14 -59.21 -217.11 N 3 8.23 140.65%

19 2,4-D 532.90 139155.79 129.98 - - N 1 21.55 99.91%

19 dicamba* -43.85 11988.52 6.63 - - N 1 10.32 99.94%

19 metsulfuron-methyl

-118.40 167772.63 -83.69 - - N 1 24.67 100.05%

23 2,4-D -7.70 747163.00 41050.10 - - N 1 21.55 94.51%

23 dicamba -37.54 421212.94 16218.22 - - N 1 10.32 96.15%

27 Chlorsulfuron 276.2385

29 2,4-D 779337.5 95532 10329.2 1559.95 99.8

29 Dicamba 108011.9 13174.6 450.112 12.67 99.99

29 Mecoprop-p 458479.3 57456.8 2681,61 112.47 99.98

30 2,4-D 442.45 384137.63 21643.47 49592.54 2988.97 Y 3 21.55 99.22%

30 dicamba 235.90 100735.21 1502.34 7423.33 -50.15 Y 3 10.32 100.05%

30 metsulfuron-methyl

132.05 120203.27 118.12 511.41 -108.85 Y 3 24.67 100.09%

30 picloram 237.51 4047333.63 5242.11 9286.65 414.33 Y 3 200.9 99.99%

31 2.4-D* 16.70 54010.53 785.74 x 221.78 Y 3 21.55 99.59%

31 dicamba -23.82 561191.14 3312.43 x 303.27 Y 3 10.32 99.95%

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34 2,4-D 48.41 404112.60 38923.92 4837.52 284.43 N 3 21.55 99.93%

34 dicamba -26.74 4168.51 259.54 44.73 -13.37 N 3 10.32 100.32%

35 aminopyralid

N/D

35 Chlorsulfuron 74.52129

36 2,4-D 3.61 637377.29 37775.82 2590.87 - N 2 21.55 99.59%

36 dicamba -25.54 104341.54 3335.82 179.71 - N 2 10.32 99.83%

38 picloram N/D

38 2,4-D 1651.996

39 2,4-D 5.16 1015287.53 2120.66 1993.17 1112.73 Y 3 21.55 99.89%

39 dicamba -30.27 1872.95 139.57 350.46 35.06 Y 3 10.32 98.13%

42 2,4-D 0.16 97383.11 15413.79 5396.66 205.27 Y 3 21.55 99.79%

42 aminopyralid 45.81 3059428.15 171467.40 1842.82 272.00 Y 3 185.5 99.99%

42 dicamba -36.03 55100.07 6404.72 277.77 -16.62 Y 3 10.32 100.03%

42 picloram 217.52 157053.88 13069.88 1249.22 200.25 Y 3 200.9 99.87%

43 2,4-D -0.96 15445.42 158.61 65.09 120.22 Y 3 21.55 99.22%

45 2,4-D 75.03 76549.84 31898.89 700.02 1232.28 Y 3 21.55 98.39%

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45 dicamba -42.93 538861.13 17401.74 1461.38 100.51 Y 3 10.32 99.98%

46 2,4-D N/D

46 mecoprop-p N/D

46 dicamba N/D

46 clopyralid N/D

47 2,4-D -12.80 347061.61 5263.29 6263.30 180.72 Y 3 21.55 99.95%

47 dicamba* -29.32 4501.81 91.04 16.04 30.50 Y 3 10.32 99.32%

47 picloram 166.41 1313880.58 6346.27 7848.63 216.78 Y 3 200.9 99.98%

48 2,4-D -3.88 50789.46 209.23 1768.14 132.62 Y 3 21.55 99.74%

48 fluroxypyr -153.55 8037.95 -116.41 150.07 -47.37 Y 3 46.66 100.59%

50 2,4-D 44.10 70106.00 85275.95 60412.25 18668.31 Y 3 21.55 73.37%

50 dicamba* 480.98 321284.17 110982.51 52869.02 5162.44 Y 3 10.32 98.39%

50 metsulfuron- methyl

-74.17 15029.05 11729.16 2617.01 94.64 Y 3 24.67 99.37%

51 2,4-D 61472 3260.9 1231.21 98.00

51 Dicamba 3295 2776.92 60.52 98.16

51 clopyralid

Not detectable

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52 aminopyralid

not detectable

52 Chlorsulfuron

not detectable

52 fluroxypyr

not detectable

52 2,4-D

not detectable

52 dicamba*

not detectable

58 2,4-D 1054738.2 9295.038 99.12%

58 picloram 1202376.5 1386.906 99.88%

59 dicamba

not detectable

59 clopyralid

not detectable

59 fluroxypyr

not detectable

61 2,4-D 314673.5 44.1 8143.45 7274.22 99.99%

62 2,4-D -8.64 397640.01 8716.61 760.34 -10.28 Y 3 21.55 100.00%

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62 dicamba -38.06 650449.66 6769.75 654.41 -3.76 Y 3 10.32 100.00%

74 Imazapyr

75 2,4-D

75 Dicamba

Chlorsulfuron 52754.234 -127.999 100.24%

75 aminopyralid 50169.353 287.1794 99.43%

77 2,4-D 92.93 248154.53 28527.35 55570.65 - Y 2 21.55 77.61%

77 dicamba -9.55 588743.36 12041.01 33024.73 - Y 2 10.32 94.39%

79 2,4-D 311.15 898864.91 106188.14 6991.16 239.00 N 3 21.55 99.97%

79 dicamba 88.30 339291.88 34648.25 1319.95 71.24 N 3 10.32 99.98%

80 2,4-D 10.99 2088.71 415.65 175.46 35.00 N 3 21.55 98.32%

80 dicamba -34.14 408.32 60.58 18.23 -17.80 N 3 10.32 104.36%

81 2,4-D -1.62 17224.25 2015.21 415.88 387.58 N 3 21.55 97.75%

81 clethodim -4.99 2028.23 1695.42 31.03 -0.08 N 3 17.75 100.00%

82 2,4-D* -12.02 5681.83 309.78 803.80 17.61 Y 3 21.55 99.69%

82 dicamba -21.54 4376.02 235.23 12.29 -10.61 Y 3 10.32 100.24%

87 2,4-D 9413.223

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87 dicamba 1541.065

92 2,4-D 2942.796

24 dicamba -58.9056

24 mesotrione 9413.223

52 | P a g e

We note that of 8 instances of samples with recent use of pesticides detectably by LC-UV, only 2 contained pesticides above detection limits. However, both of these samples showed high concentrations, despite both applicators using a cleaner. A vast amount of LC-MS/MS data was acquired, and is still being analyzed. Preliminary analysis shows similar result to LC-UV analysis, with >98% cleanout by the third rinse for most, but not all pesticides.

Aminopyralid, chlorsulfuron, clethodim, clopyralid, imazapyr, mesotrione, and triclopyr were not detected in more than one sample. We must conclude that either these pesticides are not widely used, were more easily cleaned, or were used in significantly lower quantities as to be below our detection limits. There are fewer (two to four) samples of metsulfuron-methyl, picloram, mecoprop-p and fluroxypyr. This small number of samples makes interpreting statistics impossible, but we do note that cleanout efficiency for the third rinse was not less than 99.4% effective. Concentrations for fluroxypyr were below the detection limit for every final rinse. All complete sample sets for all pesticides demonstrated the trend of exponentially decreasing pesticide concentrations for each rinse.

A large enough number of samples showed recent use of 2,4-D and dicamba to warrant statistical analysis. The average Jar 5 concentration for 2,4-D was 3308 ± 1202 ppb (standard error, n=29 datapoints). The range of concentrations was from below the detection limit (22 ppb) to 29,208 ppb. The average percent cleanout was 97.9%, but only one sample showed a cleanout efficiency less than 97% (sample 50 show a 74% cleanout rate, with a final concentration of 18,668 ppb of 2,4-D).

Figure 7. 2,4-D concentrations detected in the five sample jars for each complete set of samples: background (1), unrinsed pesticide (2), and 1st, 2nd and 3rd rinses (samples 3-5). Note that 2,4-D is on a logarithmic scale.

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Dicamba showed much lower concentrations in final jar samples than 2,4-D, with no clean-out efficiencies less than 98%. The final cleanout rinse has an average concentration of 408 ppb, but this seems to be pulled by two samples (87 and 50), which show final concentrations over 1000 ppb. Excluding these two points, dicamba shows an average final concentration of 98 ppb, despite initial concentrations of over 240 ppm!

Figure 8.Dicamba concentrations detected in the five sample jars for each complete set of samples: background (1), unrinsed pesticide (2), and 1st, 2nd and 3rd rinses (samples 3-5). Note that [dicamba] is on a logarithmic scale.

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Summary

Part 1 - Survey

The survey method proved to be an effective tool to determine the methods applicators use to clean their spray equipment as well as the challenges they must overcome. The results indicate areas which pesticide safety educators should cover in applicator trainings. The majority of the respondents had more than 3 years of experience, indicating that they are familiar with the practices used for cleaning equipment but also suggest they may have established methods for cleaning and may be resistant to change.

As noted throughout the report, areas where pesticide safety educators can provide interventions and recommendations to improve worker health and reduce loss of non-target species include:

• Emphasizing that Personal Protective Equipment (PPE) should be worn while cleaning equipment and to select the most restrictive PPE required based on the pesticide products AND the tank cleaner used.

• As a result of the analyses of samples submitted, three rinses are very effective at removing most of the residues compared to even two rinses.

• Appropriate sites for cleaning application equipment to avoid groundwater and surface water contamination.

• Proper disposal of rinsates including how much clean water should be added to the tank for cleanout. This information will include limitations on how much water to use based on the size of the tank and the ability to dispose of rinsates.

• Information on how to select the appropriate tank cleaner based on the pesticide products in the tank.

• Use of tank rinsing nozzles and modifying boom ends for easier cleanout can improve removal of pesticides.

• Remind applicators to clean inline screens and check hoses and boom lines for cracks where pesticides can accumulate.

Part 2 – Sample analysis

Samples from pesticide cleanout procedures were collected from 46 individual pesticide applicators and tested for recently used pesticides using both a standard LC-MS/MS (liquid chromatography coupled to an electrospray dual quadrupole mass spectrometer) and novel LC-UV technique. We developed a multi-residue method for quantifying aqueous pesticides using LC-UV. While less sensitive than traditional LC-MS system, this approach is sensitive enough to test in the range of acceptable levels (parts per million). We demonstrated our ability to quantify aqueous pesticides using LC-MS/MS, with very low detection limits (parts per billion).

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The LC-UV technique was demonstrated to have detection limits in the parts per million range, while LC-MS/MS has detection limits for a much wider range of pesticides in the parts per billion range. The industry standard of three repeated rinses removes the majority (typically >98%) of pesticide, although we note that there are a few individuals with much lower removal efficiencies. Perhaps unsurprisingly, final rinsate concentrations of 2,4-D typically remain above typical thresholds for drinking water; these results should be used as a reminder for applicators of the importance of wearing personal protective equipment throughout the cleaning process, and to consider placing even the third rinse back on the areas to which they were applied.

The standard ‘three rinses’ appears to remove the bulk (i.e. >98%) of the pesticide initially placed in containers. However, we note that the final rinses for many applicators still showed pesticide levels substantially higher than the minimum allowable concentrations (Table 1), and should thus still be treated with care using proper personal protective equipment. Applicators using 2,4-D should be particularly careful of post-cleanout usage on off-target samples. Preliminary data suggests cleaner may be unnecessary in the tank cleaning process, but further data analysis is required.

Activities, Products, and Future Directions.

Oral Presentations not previously reported to HICAHS:

Koty Swanson. “Quantitative analysis of pesticide tank rinses for residues”. Poster and oral (July 18th, 2013) presentation as part of Colorado State University Chemistry Research Experience for Undergraduates Program.

Koty Swanson. “Quantitative analysis of pesticide tank rinses for residues”.South Eastern Regional ACS

Koty Swanson. “Quantitative analysis of pesticide tank rinses for residues”. Accepted to Successful Student Chapter Poster Session with undergraduate funding for 247th National ACS meeting in Dallas, TX.

Thia Walker. “A Glimpse at Real-World Sprayer Cleanout: Results from Aerial Spray Equipment.” Colorado Agricultural Aviation Association, Loveland Colorado. November 21, 2013.

Future Oral Presentations

Thia Walker. “Real World Pesticide Use Issues”. 14th Annual Pesticide Stewardship Conference, San Diego, CA on Thursday February 6, 2014.

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Thia Walker. PowerPoint Presentation on HICAHS Survey and Sampling Results. Will be presented at the following location/dates:

Rocky Mountain Agribusiness Association January 16, 2014 Greeley Farm Show January 29, 2014 ProGreen Expo February 13, 2014 Tri River Area Pest Management Workshop February 18, 2014 Adams County CEC Workshop February 21, 2014 Fort Morgan CEC Workshop February 24, 2014 Sterling CEC Workshop February 25, 2014 Irrigation Research Farm CEC Workshop February 26, 2014 Akron CEC Workshop February 27, 2014 Burlington CEC Workshop February 28, 2014 CO Assoc. Lawn Care Professionals March 5, 2014 Weld County CEC workshop March 11, 2014 Eads CEC Workshop March 13, 2014 Lamar CEC Workshop March 14, 2014

Products

• A short video demonstrating a cleanout process for a large commercial sprayer will be submitted to HICAHS.

• A PowerPoint presentation is currently being developed which will incorporate some of the results of the survey to serve as talking points as well as the results of the cleanout sample study. This PowerPoint will be shared with other pesticide safety educators in the United States, Canada, and US Territories.

• Articles will be prepared for submission to peer-reviewed journals in areas of crop production, pesticide safety education, and environmental chemistry.

• An extension publication on cleaning and winterizing sprayers in development with Dr. Fred Whitford of Purdue University.

Future Directions

As a result of this research, a cooperative working relationship has formed between the Department of Chemistry and Bioagricultural Sciences and Pest Management. There have been further discussions on possible future projects between these two departments as a result. This project has also provided very important preliminary information on methods used by pesticide applicators to clean their spray equipment and how effective these methods might be in removing pesticide residues. This information

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will be used to pursue additional funding to research the effectiveness of sprayer cleanout procedures under controlled environments.

REFERENCES

Bretthauer, Scott. 2006. Cleaning your sprayer. News Release dated October 22, 2006. University of Illinois Extension, Urbana, Illinois.

Duncan, Celestine. 2011. Cleaning and Winterizing Your Herbicide Sprayer. Techline News, TechNotes http://tinyurl.com/winterizingeq

Wilson, G., W. Kirkpatrick, C. Capps, A. Vangilder, T. Barber, P. Spradley, and S. Sadaka. 2013. Burn It Down, Clean It Up. Avoiding Crop Injury Due to Sprayer Contamination. FSA2170 University of Arkansas, Little Rock, Arkansas.

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Appendix

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Appendix: Methodology for LC-ESI-MS/MS quantitation techniques.

Calibration Standard

Concentration (ppb)

Preparation Sample Volume (µl)

Concentrated stock 1.0 x 106 10 mg of pesticide standard into 10,000 µl acetonitrile

10,000 x 32 samples

Concentrated mixture

31,250 100 µl of each of the 32 concentrated stock solutions

3,200

Level 5 10,000 480 µl of concentrated mixture into 1,020 µl water

1,500

Level 4.2 6,000 276 µl of concentrated mixture into 1,224 µl water

1,500

Level 4.1 3,000 300 µl of level 5 into 700 µl of water 1,000 Level 4 1,000 150 µl of level 5 into 1,350 µl of water 1,500 Level 3.1 500 167 µl of level 4-1 into 833 µl of water 1,000 Level 3 100 15.0 µl of level 5 into 1,485 µl of water 1,500 Level 2 10 150 µl of level 3 into 1,350 µl of water 1,500 Level 1 1 15.0 µl of level 3 into 1,485 µl of water 1,500

Table x: All concentrated stock pesticide standards were prepared in HPLC grade acetonitrile excluding glyphosate, which was prepared in HPLC grade water. The standard mixtures, level 5

through level 1 were diluted into HPLC grade water. All standards were prepared by volume and massed in triplicate.

Time (min) Mobile Phase (A : B) 0.00 80% A : 20% B 20.00 0 % A : 100% B 22.00 0 % A : 100% B 22.50 80% A : 20% B 31.50 80% A : 20% B

Table x: LC gradient profile. Mobile phase A: water 0.1% formic acid. Mobile phase B: acetonitrile 0.1% formic acid.

Parameter Setting Runtime 31.50 min Flow rate 0.250

ml/min Injection volume 20.0 µl Column temperature

45 ◦C

Auto sampler tray 4 ◦C Table x: LC instrument parameters.

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Parameter Setting Sheath gas flow rate 35 arb Spray voltage 4.3 kV Capillary voltage -4.00 V Capillary temperature 180 ◦C Tube lens offset 20.00 V MS/MS percentage collision energy

38%

Table x: Electrospray ionization, ESI, negative mode, parameters.

MS/MS Segment

Time (min) Pesticide Parent Ion (m/z) Product Ion (m/z)

1 2.92 aminopyralid 205.1 159, 187 2 3.69 clopyralid 190.3 146 3 4.11 imazapyr 160.4 215, 232 4 4.77 picloram 239.2 195 5 5.72 imazamox 304.4 259 6 8.96 fluroxypyr 253.4 207, 179 7 9.90 dicamba 219.3 175 8 10.78 metsulfuron-methyl 380.5 165, 139 9 11.50 chlorsulfuron 356.6 139, 165 10 12.95 2,4-D 219.4 161 11 13.91 mecoprop-p 213.5 213, 215 12 15.60 triflusulfuron-

methyl 491.4 262, 239

13 16.50 oryzalin 345.7 281 14 22.10 clethodim 358.7 Table x: Summary of tandem mass spectrometry segments, time span, and pesticide collision

information using electrospray ionization (ESI) negative mode. Every segment utilizes two scanning events. The first scanning event is a total ion chromatogram within the ion range of

100-850 m/z. The second scanning even is a tandem mass spectrum, which selected parent ion and bombards it with inert gas, helium, causing collision induced dissociation of the parent ion,

forming the product ion(s).

Supplemental Information on LC-MS/MS system:

Waters BEH XBridge C18 XP column (130 Å, 2.5 µm, 2.1 mm x 100 mm), Part Number: 186006031

Method: C:\Xcalibur\methods\Farmer\130722_Multi_seg_negative_mode_PO (for triclopyr: C:\Xcalibur\methods\Farmer\130722_Multi_seg_negative_mode_4_PO)

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(for mesotrione: C:\Xcalibur\methods\Farmer\130722_Multi_seg_negative_mode_24_PO) Tune method for all segments: C:\Xcalibur\methods\Farmer\PestTune02Jul13B.LCQTune Sequence: C:\Xcalibur\methods\Farmer\130726_ESI_neg_Cal_L3,L3-1,L4,L4-1,L4-2,L5, SAMPLES