Illinois Pesticide Review
January / February 2015
In This Issue
Paraquat Dichloride: One Sip Can Kill
This topic is heartbreaking but needs to be addressed. At EPA's request, we are warning the pesticide applicator community about the high toxicity of paraquat dichloride and the need to prevent accidental ingestions.
Paraquat dichloride, commonly referred to as paraquat, is a non-selective contact herbicide sold as Gramoxone and many others. There are 11 products registered in Illinois. It is a Restricted Use Product sold to certified applicators only and for use by certified applicators and those under their direct supervision only.
A recent EPA incident investigation found cases of eight deaths due to the accidental ingestion of paraquat dichloride. All eight accidental deaths involved the transfer of paraquat dichloride into a beverage container. The labels of paraquat clearly state "NEVER PUT INTO FOOD, DRINK OR OTHER CONTAINERS." Yet this happens occasionally, which can lead to tragic results. The PSEP program has always addressed the dangers of this practice in our training materials and at our training clinics. We will continue to do so.
The information below, however, brings real-world examples to this discussion. As applicators, we think that tragic events are things we hear about on the news. They won't happen to us. We are more careful. As educators, we falsely believe that warning someone of the hazards is simply enough. As parents, we think that our kids would never drink some unknown beverage out in the garage. They know better, right? Still, the unthinkable can occur. With something this toxic, there is little room for error; one sip can kill. Let's work together to up our game a bit to prevent future accidental deaths.
One might ask, "Shouldn't manufacturers take part in this effort?" From what I've read, they have and will likely continue to do so. Many formulations of paraquat include an emetic that induces vomiting. Additionally, many have a strong, deterring odor and a green color. These have replaced original formulations that were reddish-brown and looked similar to tea, cola, and wine. In 2006, we wrote about a novel Syngenta formulation (Inteon) that included an alginate that works by forming a protective barrier when it comes in contact with stomach acid. It also included a purgative to enhance excretion. The idea was for the body to move the paraquat out as quickly as possible in all directions. The article can be found at http://web.extension.illinois.edu/ipr/i4147_829.html#57064.
Inteon unfortunately had some mixing issues, likely from the alginate, and has since been replaced by Syngenta with the SL formulation, which provides improved mixing. It also contains an alerting agent (odor), an emetic, and dye. Still, there are many manufacturers of paraquat, which is used around the world. Not all formulations contain safeguards.
In the American Association of Poison Control Centers letter that is provided below, the request is made via EPA that manufacturers dilute their formulations so that a small dose would not be fatal – an excellent idea. This could be the catalyst for safety improvements.
Many thanks to EPA for sharing their recent investigation findings, which follows as provided by EPA.
The Accidental Poisoning Problem
The California Poison Control System and the Central California Children's Hospital reviewed data from 1998-2009 and identified more than 1,400 cases of accidental poisonings caused by storage of non-food substances in soda bottles, unmarked bottles, cups or glasses. Several of the deaths involved the accidental ingestion of pesticides, including paraquat.1
Recent Deaths from the Accidental Ingestion of Paraquat
The California Poison Control System and the American Association of Poison Control Centers (AAPCC) recently sent letters of concern to EPA regarding a series of deaths from accidental ingestion of the pesticide paraquat in the San Joaquin Valley of California. AAPCC cited 50 deaths from paraquat; at least 12 were from accidental ingestion of paraquat from a beverage container.
This is a major concern to EPA because paraquat is a Restricted Use Pesticide that should not be accessible to the general public and, as with all pesticides, should never be placed into a beverage container. Paraquat is highly toxic to humans; one small accidental sip can be fatal and there is no antidote.
The product labels clearly prohibit pouring paraquat into food or beverage containers with the prominently placed statements "NEVER PUT INTO FOOD, DRINK OR OTHER CONTAINERS" and "DO NOT REMOVE CONTENTS EXCEPT FOR IMMEDIATE USE."
Paraquat Use Profile
Paraquat dichloride, commonly referred to as "paraquat," is an herbicide registered in the United States since 1964 to control weeds in many agricultural and non-agricultural use sites. It is also applied as a pre-harvest desiccant on some crops including cotton.
All paraquat products registered for use in the United States are Restricted Use Pesticides (RUPs), which can only be sold to and used by certified applicators (and applicators under their direct supervision). There are no homeowner uses and no products registered for application in residential areas.
EPA Incident Investigation
The fatalities resulting from paraquat products transferred into beverage containers in California prompted EPA to investigate all reported cases. EPA conducted an investigation of all reports of fatal and high-severity paraquat incidents. EPA identified 27 paraquat fatality reports to date in its Incident Data System (IDS). The IDS database contains all registrant submissions of adverse health effects from pesticide products, as required by federal law (FIFRA §6(a)(2)). More than 80% of all identified paraquat fatality cases reported to IDS were due to ingestion of the product.
At least eight of these 27 deaths were due to the accidental ingestion of paraquat. All eight of these accidental deaths involved transfer of paraquat into a beverage container. Several of these cases have occurred recently. A review of the SENSOR-Pesticides data identified additional ingestion cases, including the fatal case of an 8-year-old child who drank the paraquat out of a soda bottle.
• In 2013, a 70-year-old female ingested some contents of a re-used iced tea bottle that contained paraquat, unknown to her. She went to the hospital awake and alert with persistent vomiting. Over the course of a 16-day admission, she evolved the classic picture of paraquat ingestion: corrosive gastrointestinal injury plus kidney and respiratory failure leading to death.
• In 2010, a 44-year-old male mistakenly drank paraquat, which he thought was fruit juice. He developed difficulty breathing and vomited blood. He was admitted to the hospital intensive care unit where he died after 20 days of aggressive treatment.
• In 2008, an 8-year-old boy drank paraquat that had been put in a Dr. Pepper bottle, which he found on a window sill in the garage. He died in the hospital 16 days later. His older brother had used the product on weeds around the house and put it in the bottle in the garage. The older brother obtained the product from a family friend who is a certified Restricted Use Pesticide applicator.
• In 2003, a 49-year-old male took a sip from his coffee cup in which he had poured paraquat because the product's bottle was deteriorating. He realized his mistake and went to the Emergency Department. At that time, he was vomiting, cold and sweating profusely. Doses of activated charcoal were administered and his stomach was pumped; morphine was provided for esophageal pain; and he was intubated to support breathing function on the fourth day. Aggressive supportive care continued until he died on the tenth day.
• In 2000, a 15-month-old boy ingested paraquat that had been transferred into a Gatorade container and stored inappropriately. The boy survived in the hospital for 13 days after the ingestion and received aggressive treatment but died after suffering acute kidney and liver failure.
• In 2000, an 18-month-old boy ingested an unknown amount of paraquat solution from a bottle found in his father's landscaping truck. He received multiple-dose activated charcoal treatment two hours after the ingestion. He suffered from lack of oxygen during the first 24 hours followed by progressive liver, kidney, and cardio-pulmonary dysfunction. The boy died 11 days after the ingestion.
While EPA determines the appropriate regulatory response, we want to warn the applicator community about the high toxicity of paraquat.
It is the responsibility of pesticide applicators to ensure that RUP products are used safely and appropriately, including never transferring any pesticide product, including paraquat, into a beverage container.
The Solution is YOU
ONE SIP CAN KILL!
To prevent the severe injury and/or death from paraquat ingestion, a paraquat product must:
• Be used only by a certified applicator or under the direct supervision of a certified applicator;
• Never be transferred to a food, drink or any other container;
• Always be kept secured to prevent access by children and/or other unauthorized persons;
• Never be stored in or around residential dwellings; and
• Never be used around home gardens, schools, recreational parks, golf courses or playgrounds.
Paraquat Dichloride Information Resources
• EPA's Paraquat Dichloride Registration Review Docket, EPA-HQ-OPP-2011-0855, for information on EPA's current re-evaluation of paraquat. This docket includes a letter from Dr. Gellar (California Poison Control System), the EPA response, and the AAPCC letter. http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2011-0855
• Syngenta's Paraquat Information Center: www.paraquat.com/safety
EPA email sent 12/24/14 to American Association of Pesticide Safety Educators members.
Nozzle Wear: What Happens When Your Orifice Gets Bigger
As nozzles are used to apply pesticide sprays, they gradually wear out. The part of the nozzle that wears out is the orifice. Over time the spray passing through the orifice erodes the surface. The main change that occurs as the orifice wears over time is an increase in flow rate. There are, however, several other things that change too, including spray pattern and droplet size.
Nozzle flow rate is measured in gallons per minute, or GPM. It is often measured in fluid ounces and converted to gallons in order to make a more accurate measurement. You should measure the flow rate from your nozzles when you first set up the sprayer to verify they are outputting the desired flow rate. Following this initial calibration and setup, periodically check the flow rate to see if it has increased. If it has, and the increase is more than 10 percent of the original flow rate, then it is time to replace the nozzle.
As an example, let's say you are calibrating a sprayer to a spray application rate of 10 gallons per acre. Your average travel speed is 13 miles per hour and your nozzles are 20 inches apart. Using the University of Illinois Sprayer Calibration app, you determine that you need a flow rate out of your nozzle of 0.44 GPM. You select an 11004 pre-orifice nozzle, which you will operate at 48 psi in order to achieve the required flow rate. To verify the correct output, you convert 0.44 GPM into fluid ounces per minute, which is 56. Operate the sprayer at 48 psi, collect sprayer from the nozzles for one minute, and confirm the output is 56 fluid ounces.
After getting a month into your spraying season, you decide to recheck nozzle flow rate for a few nozzles on the boom to determine if there has been an increase in flow. You find the average flow rate from the nozzles you measure is 58 fluid ounces per minute, which is 0.45 GPM. This does not necessitate a nozzle change, as an increase of 0.01 GPM is only a 2 percent increase in flow rate. A recheck at the end of the spraying season shows an average flow rate of 0.49 GPM. This is an increase of 0.05 GPM from the original flow and represents an 11 percent increase in flow rate. This is greater than the recommended 10 percent increase, so it is now time to change your nozzles.
As your nozzle wears, the spray pattern also changes. The orifice on a flat fan nozzle is elliptical, which causes it to create a flat fan spray pattern, with the heaviest concentration of spray in the center of the pattern and tapering off to nothing at the edges. As the orifice wears, though, it becomes more circular in shape. This has the overall effect of reducing the width of the spray pattern. This would be like slowly going from a 110-degree fan angle to an 80-degree fan angle. A narrower spray pattern will reduce overlap between adjacent nozzle patterns. If boom height is not increased to compensate, this reduction in overlap could result in a decrease in spray uniformity along the length of the spray boom and skips in coverage. If boom height is increased to compensate for the narrowing spray pattern, the risk of drift can increase.
The third change that occurs as a nozzle wears is droplet size. As the orifice increases in size, the droplet size also increases. Furthermore, the narrowing of the spray angle also increases the droplet size. Droplet size impacts both efficacy and drift potential. Smaller droplets tend to provide better coverage and deposition but are also more likely to drift off-target, as they are lighter. So the increase in droplets size as the orifice wears will improve drift mitigation but potentially reduce efficacy. In either case, it will certainly change from the droplet size you were targeting when you calibrated your sprayer.
As an example of the impact of the increasing orifice size and decreasing fan angle on droplet size, we can examine the volume median diameter for a series of extended-range flat nozzles. The volume median diameter, or VMD, is the droplet diameter where half of the spray volume comes out in droplets smaller then the VMD and the other half comes out in droplets larger than the VMD. Table 1 shows the VMDs for a range of extended-range orifice sizes and fan angles. Two trends are clearly visible. First, as orifice size increases (except for the 04 to 05 transition for the 110-degree flat fan), so does droplet size. Second, as fan angle decreases, droplet size increases. Nozzle wear creates a combination of increasing orifice size with narrowing fan angle (Table 1).
How quickly a nozzle wears out depends on the material it is made of as well as the material sprayed through it. More abrasive products will cause wear to occur more rapidly. In terms of nozzle manufacturing, there are a variety of materials a nozzle can be made from, including brass, stainless steel, various types of plastics, and ceramic. Brass is the least wear resistant, while ceramic is the most wear resistant. There are various types of plastics, or polymers, that can be used to manufacture nozzles and some of them are as or more wear resistant than stainless steel. Figure 1 shows the average wear rate ratios for the most common types of materials nozzles can be manufactured from. Ceramic is the most wear resistant material; stainless steel wear resistance falls between the different types of plastics used to make nozzles.
In summary, nozzles wear with use. This wear causes an increase in flow rate, a decrease in spray pattern width, and an increase in spray droplet size. This has an impact on the efficacy and safety of the pesticide applications you make, so nozzle wear should not be overlooked. Check you nozzle flow rates on a regular basis to make sure your applications are as effective as possible.Scott Bretthauer (firstname.lastname@example.org)
Dr. Loren Bode served almost continually as the Coordinator of the University of Illinois Pesticide Safety Education Program (PSEP) from 1991 through 2013. He also taught pesticide equipment and calibration at many of the Pesticide Applicator Training Clinics into the mid-1980s. He died on December 3, 2014 at age 71. His complete obituary can be accessed at http://www.news-gazette.com/obituaries/2014-12-06/loren-bode.html.
Loren joined the Agricultural Engineering Department at the University of Illinois in September 1973 and served as faculty member in the department until his retirement in 2008. He became the fifth head of the department in 1993 and served in that role through December 2004.
Four decades of research, teaching and extension resulted in Loren being an acknowledged international authority regarding the design and use of equipment for applying agricultural chemicals. The approach he helped develop for calibrating sprayers and other pesticide application equipment is currently being used throughout the U.S. and around the world. He has written more than 200 publications and has been recognized with many rewards and honors.
Throughout his years as PSEP Coordinator, Loren was instrumental in smoothing out the rough spots that occurred with University of Illinois, Illinois Department of Agriculture, USEPA, and USDA administrators and personnel as well as with PSEP clientele. His calm, soothing manner tended to defuse contentious situations, eliminate emotional baggage, and reduce the issues to important points that could be intelligently addressed. The high level of respect he commanded within the university, the state, and among clientele was extremely helpful on numerous occasions.
Loren Bode's passion and professionalism were an inspiration to everyone who had the good fortune to work with him. He could motivate those around him to strive for excellence and always try to improve things. He had an enthusiasm that was contagious and his presence always made wherever he was a better, happier place. When the time came for criticism, he was honest and forward, but never harsh or demeaning. His advice and council made you a better person. Loren was as much a family man as he was a professional. He had a zest for life and was sure to remind others of "what life's all about".
He functioned as a mentor to the PSEP specialists that taught at pesticide training clinics through the years as well as those currently doing so. His guidance to us was immeasurable and impossible to completely express. Those of us in the PSEP program will miss him and be thankful for him throughout our lives.
Monarch Butterfly – Endangered Species?
Monarch butterflies (Danaus plexippus) are easily recognized by most people, being the Illinois State Insect. It reproduces as far north as southern Canada, migrating down the east coast and through the midwest to overwinter in large numbers in mountain forests north of Mexico City. Those in the western U.S. overwinter in several locations in forests along the California coast.
There has been a huge drop in the number of monarch butterflies in recent years. In the 1990s, estimates of up to one billion monarchs flew from central North America to overwinter in Mexico, and more than one million monarchs overwintered in California. Now, researchers and citizen scientists estimate that only about 33 million monarchs remain, representing more than a 90% drop across North America. Threats to monarch butterflies include habitat loss – particularly the loss of milkweed, the monarch caterpillar's sole food source – and mortality resulting from pesticide use.
The U.S. Fish and Wildlife Service announced on December 29, 2014 that it will be conducting a status review of the monarch butterfly under the Endangered Species Act (ESA). The Service has determined that a petition from the Center for Biological Diversity, the Center for Food Safety, the Xerces Society for Invertebrate Conservation, and Dr. Lincoln Brower to list a subspecies of monarch (Danaus plexippus plexippus) presents substantial information indicating that listing may be warranted.
To ensure this status review is comprehensive, the Service is requesting scientific and commercial data and other information through a 60-day public information period. Specifically, the Service seeks information including:
• The subspecies' biology, range and population trends, habitat requirements, genetics and taxonomy;
• Historical and current range, including distribution patterns;
• Historical and current population levels and current and projected trends;
• The life history or behavior of the monarch butterfly that has not yet been documented;
• Thermo-tolerance range and microclimate requirements of the monarch butterfly;
• Past and ongoing conservation measures for the subspecies, its habitat or both; and,
• Factors that are the basis for making a listing determination under section 4(a) of the ESA;
The notice was published in the Federal Register December 31, 2014, and it is requested that information be received by March 2, 2015. To view the notice and submit information, visit www.regulations.gov, docket number FWS-R3-ES-2014-0056.
Nationally, the Xerces Society's partnership with the USDA NRCS has resulted in planting more than 120,000 acres of habitat for monarchs and other pollinators, including tens of thousands of diverse wildflower plantings that include milkweed. The Xerces Society is also working to increase the availability of native seed and to make it less expensive to use in restoration activities.
However, not all species of milkweed are equally beneficial. One milkweed species that is popular with gardeners is a tropical species frequently called bloodflower, (Asclepias curassavica). Tropical milkweeds continue growing with green leaves attractive to monarch egg-laying right up until frost, with the plants and remaining monarchs being killed by winter weather. Midwestern gardeners grow this tender perennial as an annual, planting seed or transplants each spring, not realizing its ability to trap and inadvertently kill late-season monarchs.
In the southern U.S., this tropical milkweed continues to grow and support monarch larvae through the winter, selecting for monarchs that do not migrate to Mexico. These monarchs that do not migrate have been found to have a higher infection rate by the protozoan Ophryocystis elektroscirrha, which causes the resulting butterflies to have wing deformities, smaller body size, reduced flight performance, and shorter adult lifespans.
Southern plantings of these tropical milkweeds function as a trap to infect the larvae of passing migrating monarch butterflies, further reducing the number of butterflies that are able to migrate.
Phil Nixon (email@example.com)