Open Forum: In an attempt to promote free and open discussion of issues, The Agrichemical and Environmental News encourages letters and articles with differing views. To discuss submission of an article, please contact Dr. Allan Felsot at 509-372-7365 or afelsot@tricity.wsu.edu; Dr. Catherine Daniels at 509-372-7495 or cdaniels@tricity.wsu.edu; or Dr. Carol Weisskopf at 509-372-7464. The newsletter is available in a hardcopy version for a $15 yearly subscription fee.
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Dr. Rick Weinzierl, Department of Crop Sciences, University of Illinois
This article was initially published in: Proceedings 1998 Illinois Small Fruit and Strawberry Schools, pp.99-102. Reprinted here with permission.
Integrated Pest Management (IPM)
Integrated pest management (IPM) is a reasonably well known concept in agriculture. It may be defined somewhat differently by different individuals, but in general, IPM is described as the use of a combination of cultural practices, resistant varieties, biological control, and pesticides to limit losses to pests (including insects, weeds, pathogens, and vertebrates) and at the same time minimize dollar costs and any adverse effects on the environment and human health. This definition clearly includes pesticides as a part of IPM; it also clearly implies that they should be used as sparingly as possible.
Most growers, if asked (and especially if asked by a concerned consumer), would state that they practice IPM. Most would say that they use pesticides only when necessary and that they are good stewards of the environment. If this is true, perhaps the practice of IPM is a story that the public should understand better and hear more often. A desire to create and then capitalize on public sentiment about IPM is what has led some growers, processors, and food retailers to propose and initiate programs for IPM certification and labeling.
A Brief History on IPM Certification and Labeling
For 20 years or more, extension specialists in land-grant universities throughout the country have worked with growers to improve their practice of IPM. Extension programs have taught or demonstrated the value of pest monitoring, resistant varieties, biological controls, and careful selection and use of pesticides. Such programs have concentrated on the economic benefits of good IPM practices...benefits to growers. Although the overall concept of IPM has been talked about and written about in the media, IPM programs have rarely focused on educating the general public about the use of pesticides in agriculture.
Public concerns about pesticides have, however, influenced agriculture in many ways. One example, reported by Hollingsworth (1994), is especially relevant to IPM labeling and certification. A grower who had participated in an IPM demonstration project in Massachusetts in the 1980's felt scorned by his non-farm neighbors who objected to his use of pesticides. He felt that he was a progressive and responsible farmer, and he asked the University of Massachusetts IPM program staff to develop a sign that he might post— a sign that would indicate his dedication to IPM and the environment. The result was a sign that read simply UMASS IPM Cooperating Grower. The sign was a success...other growers in the program wanted signs too, and all who paid their fees as program participants received signs. But were they all really practicing IPM and could the University of Massachusetts “vouch” for them? The extension staff at the University of Massachusetts answered “no” to those questions and quit producing signs.
The dilemma in Massachusetts- and elsewhere- was determining what really comprised IPM in any given crop and production area. To address this dilemma, Massachusetts' extension specialists worked with growers to define IPM by means of specific practices, not vague concepts. They have since developed commodity-specific definitions of IPM for apples, cole crops, cranberries, peppers, potatoes, squash, strawberries, sweet corn, and tomatoes (Hollingsworth et al. 1994). Definitions use a survey and scoring approach; specific IPM practices are each given weights or values, and growers score their actual compliance with these practices. To qualify as practitioners of IPM, growers must tally 70 or 80 percent of the possible points for a given commodity. (The `passing' score might vary among commodities.) Key practices for strawberries, for example, include leaf tissue analysis, crop rotation, mulching, bed renovation, sprayer calibration, use of disease resistant cultivars, using raised beds where appropriate, basing fungicide and insecticide sprays on the results of prescribed scouting methods (several specifics are included), maintaining accurate records of all pesticide use, making and filing weed maps, attending educational programs, and possessing up-to-date references on pests and pest management. Growers who practiced IPM according to these definitions were certified in the Massachusetts “Partners with Nature” program.
The Massachusetts program was a first step in IPM certification. The steps that followed are much more widely known. In 1996, Wegmans supermarket chains in New York began selling fresh sweet corn with a label that stated the crop was grown under IPM practices. With Cornell University's extension specialists, they had established a working definition of sweet corn IPM that used an approach very similar to the one in Massachusetts. By 1997, Wegmans was also marketing processed vegetables (sweet corn, peas, and more to come soon) in cans and freezer bags that bore labels stating the crop was grown under IPM practices (Heacox 1997). To accompany the labels, Wegmans produced educational videotapes, flyers, and even full-page newspaper advertisements on IPM-grown produce. These materials describe IPM in layman's terms, distinguish it from organic production, and, in general, give consumers at least a bit of an idea about food production and crop protection. Wegmans promotions focus entirely on the environmental benefits of sound IPM...they make no claims about food safety, and they openly state that there is no pesticide-related risk in “non-IPM” foods. The IPM label is part of an overall marketing campaign that Wegmans calls “food you feel good about”.
The Present and Future of IPM Certification and Labeling
Responses from the agricultural sector have been both positive and negative (Acuff 1997; Heacox 1997). Critics suggest that labeling foods as produced under IPM implies that “non-IPM” foods are inferior; they argue that calling attention to the issue of pesticides and pest management is bad for the industry; and they argue that IPM certification and labeling mean more unwanted bureaucracy. Promoters of IPM labeling note that many marketing efforts create advantages and disadvantages for different segments of the produce industry, and that IPM labeling is as justified and appropriate a basis for market advantage as most other criteria. They argue that public attention is already focused on pesticide-related issues, and that IPM labeling might provide some much-needed favorable reaction from consumers. Proponents further argue that practicing IPM, if IPM is correctly and flexibly defined for each crop and production region, is the most economical way to limit pest losses in crop production. Practicing IPM should not really be a burden to growers. Finally, they acknowledge that record keeping for IPM is indeed a necessary task; they note, however, that certification of IPM practices does not need to be (and has not been) assigned to a government agency.
Wegmans and the food processing company that supplies the grocery chain with IPM-certified produce continue to expand this program. Additional fruit and vegetable crops will be packed and sold under IPM labels in 1998. Other grocery chains have contacted the processor and are considering similar efforts. We (Cooperative Extension at the University of Illinois) have been asked to develop criteria for popcorn IPM (popcorn sold in the Wegmans stores is grown in central and southern Illinois), and we contributed to development of the definitions used for sweet corn, peas, and green beans grown for processing by member companies of the Midwest Food Processors Association.
Will IPM certification expand? What benefits will result from IPM certification and labeling? These questions remain unanswered at present. Each of us at the University of Illinois is likely to react and contribute to this issue in different ways. I consider it essential for us to develop the definitions for IPM for Illinois crops so that those definitions are both practical and substantive. I also consider doing so to be necessary so that if IPM certification is a necessary step for market access, Illinois growers are not denied potential markets. I also consider IPM certification and labeling to be processes that will focus public (consumer) attention on positive practices in crop production and pest management.
References:
Acuff, G. 1997. Labels send the wrong message. American Fruit Grower, September, 1997: 29.
Heacox, L. 1997. IPM hits the shelves. American Vegetable Grower, May, 1997: 49.
Hollingsworth, C.S. 1994. Integrated pest management certification: a sign by the side of the road. American Entomologist 40: 74-76.
Hollingsworth, C.S., W.M. Coli, and R.V. Hazzard. 1994. Integrated pest management, Massachusetts guidelines: commodity specific definitions. SP-136. Cooperative Extension, University of Massachusetts, Amherst.
Return to Table of Contents for the October 1998 issue
The third PNW “Pesticide Issues Conference: Explaining the Science behind FQPA”, will be held October 29, 1998 at the Yakima DoubleTree. The conference is being sponsored by WSU's Pesticide Education Program, Pesticide Information Center and the Food and Environmental Quality Laboratory. Six pesticide recertification credits will be given.
| TIME | TOPIC | SPEAKER |
| 7:30 AM | Registration | |
| 8:00 AM | Welcome | Carol Ramsay, WSU |
| 8:10-8:50 AM | Organophosphates and Neural Developmental Effects | Mike Hooper, Texas Tech. University |
| 9:00-10:30 AM |
Panel: Residues and Tolerances Residue, Reference Dose, and ADI Detection Levels vs. Tolerance Levels Global Harmonization of Tolerances |
Carl Winter, UC Davis Carol Weisskopf, WSU FEQL To be announced |
| 10:45-12:00 PM |
Panel: Where is the Data? FDA's Monitoring Program Pesticide Data Program Pesticide Use Statistics |
Candace Jacobs, WSDA David Brassard, EPA BEAD Allan Felsot, WSU FEQL |
| 12:00-1:00 PM | Lunch | |
| 1:00-2:10 PM |
Panel: Modeling & Risk Assessment Layperson's View of Monte Carlo Residues in Water: 10% of the Cup? Residential Exposure: 10% of the Cup? |
David Brassard, EPA BEAD Marcus Flurry, WSU Bob Kreiger, UC Riverside |
| 2:25-3:05 PM | Consumer Safety/Brochure Outreach | Carl Winter, UC Davis |
| 3:15-4:00 PM | Status of FQPA Implementation | To be announced, EPA OPP |
The conference is aimed at providing education for individuals working with pesticide issues, in particular: consultants, agrichemical industry representatives, grower associations, pest management associations, environmental organizations, educators and regulators. Registration brochures are available by calling the WSU Pesticide Education Program at 509-335-9204 or 509-335-9222, or email ltroka@wsu.edu.The registration cost will be $50 per person and cover costs of conference proceedings, brochure, mailing, lunch, refreshments and speakers. Space will be guaranteed for those registering by October 10, and on-site registrations will be welcomed if space is available.
Return to Table of Contents for the October 1998 issue
The Washington State Department of Agriculture's (WSDA) Pesticide Management Division and WSU's Food and Environmental Quality Laboratory are jointly sponsoring the Minor Crop Registration Workshop III on December 2, 1998. The all-day workshop will be held in the main auditorium of the WSU Tri-Cities campus, and focus on how to obtain Section 18 (emergency exemptions) and Section 24c (special local needs) registrations, as well as highlight available resources for obtaining these registrations. A significant amount of time will be dedicated to breakout sessions where actual examples will be used as models.
| DRAFT AGENDA | |
| 7:45-8:15 AM | Registration |
| 8:15-9:00 AM | Introductory Remarks |
| 8:30-9:00 AM |
Pesticide Information Center On-Line Pesticide Notification Network |
| 9:00-9:30 AM | Washington State IR-4 Program |
| 9:30-9:45 AM | Break |
| 9:45-10:15 AM | Washington State Commission on Pesticide Registration |
| 10:15-12:00 PM |
Introduction to Obtaining Sec. 18 and 24(c) Registrations |
| 12:00-1:00 PM | Lunch |
| 1:00-3:30 PM |
(Break out sessions) Work through one example Obtaining existing data Generating new data |
| 3:30-4:00 PM | Concluding remarks and adjourn |
This workshop is structured to provide education and assistance to individuals involved in minor crop pesticide issues, specifically, consultants, growers and/or associations and educators. Any individual or group who desires to learn more about how to obtain these registrations is encouraged to attend this free workshop. Advance registration is encouraged although on-site registrations will be accepted. To register, contact Catherine Daniels, WSU Tri-Cities, at (509) 372-7495 or email cdaniels@tricity.wsu.edu. For information on workshop content please contact Joel Kangiser, WSDA, at (360) 902-2030.
Return to Table of Contents for the October 1998 issue
The annual Washington Pest Consultants (WaPCA) meeting will be held November 1213, 1998, in Yakima, WA. Thursday morning speakers discuss landscape integrated plant health management, row crop fertility, irrigation strategies, and tree fruit pest and disease IPM. A buffet lunch will be offered with guest speaker Mac Bledsoe. Thursday afternoon's session will be devoted to examining the crop consultant's role in pesticide residue studies, recommendation liability, FQPA issues and heavy metal labeling requirements. "Beer and Bull" social and poster presentation will follow. Friday morning topics include examining the role of crop consultants in transition to organic farming. For more information contact Ellen Bentley (509) 786-9271, Ginny Prest (509) 786-9215, Russ Bowman (509) 952-8005, or point your browser to the WaPCA area of the Washington State Pesticide Page, http://pep.wsu.edu.
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Dr. Doug Walsh, Agrichemical and Environmental Specialist, WSU
I appreciate this opportunity to introduce myself to the readers of this newsletter. First, I would like to say that I am extremely pleased to have been selected to serve as Agrichemical and Environmental Specialist by Washington State University. I have a fairly diverse background in agriculture production and I bring my unique experience as well as my enthusiasm to this position.
I studied Plant Sciences and received my B.A. at U.C. Santa Cruz. In 1986, I became the Agricultural Field Assistant with U.C. Cooperative Extension in Santa Cruz County. At this job I was the technician for three commodity-based County Agents, an Integrated Pest Management Specialist, a 4H Youth Advisor, a Sea Grant Marine Advisor, and a Home Economist. It proved to be a tremendous opportunity and I learned about the culture and pest management of strawberries, apples, lettuce, caneberries, potted ornamentals, cut flowers, Cole crops, and salmon. Additionally, I earned great respect for the public service provided by Cooperative Extension.
I was promoted in 1988 to entomology/plant pathology Research Associate for strawberries and vegetables in Santa Cruz and Monterey Counties. I participated in an interdisciplinary research and implementation team consisting of entomologists, plant pathologists, plant breeders, and agricultural engineers.
In 1991, I entered the Entomology Ph.D. program at U.C. Davis. My dissertation research was a study on the susceptibility of strawberries to spider mites and determining potential mechanisms of host plant resistance. I worked closely with the California Strawberry Commission and I developed a strong and trusting relationship with that industry.
For the past 4 years I have been a co-Principal Investigator for the California Statewide Strawberry Entomology Project, responsible for ongoing pro-active research projects on pests throughout California. I worked closely with the University of California IPM, IR-4, and PIAP programs. Additionally, as a researcher in the U.C. Davis Horticultural Entomology Laboratory I participated in pest management projects on tomatoes, grapes, stone fruits and almonds. I have developed laboratory bioassay techniques to determine the effects of pesticide spray residues on tree bark and leaves on the biology of non-target organisms. I did preliminary work on the photo-degradation of pyrethroid, avermectin, and pyrole pesticides and plan to continue investigating this phenomenon and it's effects on pesticide residues and runoff.
Government regulations increase the strain for agricultural producers in an increasingly competitive market. I have been impressed by the quality of information and opinion presented in the Agrichemical and Environmental News. I look forward to a productive partnership with my new colleagues at the Food and Environmental Quality Laboratory and I will do my best to serve the interests of the agricultural industry and citizens of Washington in the maintenance of a safe environment within a rational and economically viable framework.
Dr. Walsh begins his appointment on October 1, 1998 and will be stationed at WSU's Irrigated Agriculture Research and Extension Center in Prosser. He can be reached at (509) 786-2226.
Return to Table of Contents for the October 1998 issue
Dr. Carol Weisskopf, Analytical Chemist, WSU
My August newsletter contribution dealt with what detection limits are, how they are determined, and how variability in detection limits arise. What follows is a description of residue distributions, how chemists deal with samples in which there are no residues found above the detection limits, and how they may be used in the regulatory process.
Detection limits, residue distributions and tolerances
One of the first things to consider is how pesticides are distributed in samples. This graph depicts the distribution of pesticide residue concentrations found in an actual set of samples analyzed in our laboratory as part of a registration study.
Concentrations of detected residues are grouped in 0.5 ppm intervals around the values given on the x-axes, the number of samples in each group are shown on the y-axes. The pesticide was in all treated samples, at concentrations less than 4.5 ppm but greater than 1.0 ppm. Our detection limit for the method was 0.2 ppm. The distribution of these data are typical; more samples are found at concentrations in the middle of the range. With a large sample set, the distribution would look like a bell curve, occasionally skewed towards the high or low end of the range.
If the tolerance for this chemical on the crop was 50 ppm, the relationship between detection limit, residues and tolerance would be ideal for both science and regulatory policy. The highest residue would be comfortably below the tolerance, with a method detection limit well below concentrations of interest. If our detection limit had been 2.0 ppm, 10 times higher than we were actually able to achieve, it would still give us sufficient information for a tolerance of 50 ppm despite the occurrence of non-detects in about half of the samples. But if the tolerance was only 5 ppm, it is certain that the application pattern would eventually result in a residue over the tolerance.
Despite the ability to achieve a detection limit of 0.2 ppm, analyzing the samples at a detection limit of 2.0 ppm would have been less expensive, faster and easier, and method development less arduous.
The least informative result from an analysis is that the sample does not contain the compound at a concentration above the detection limit. This is sufficient information if your only objective is to determine if a sample exceeds a particular level, such as a tolerance, and the detection limit is below that level. With current instrumentation, we are able to achieve better sensitivity than that cited in many analytical methods used for registrations of older compounds. Until recently, there was little incentive in commodity analyses to push detection limits significantly below those needed to assess relationships between sample residues and tolerances.
Dealing with non-detections
How a result is handled when concentrations are below the method detection limit depends on what you will be doing with the results. On an individual basis, we report the sample as containing a concentration less than the detection limit of the method (e. g. < 0.2 ppm). We would also report this as the average if no residues were found in any sample in a set. If we are taking a concentration average for a group of samples in which some were found to contain detectable concentrations and some were not, several methods can be used. The one approach we don't take is to include the value as 0 ppm.
If most of the samples have detected residues, I often include the non-detects in calculations at a level equivalent to half of the detection limit. This is a reasonable approach when examining environmental distributions of chemicals, as it assumes some of the non-detect samples contain concentrations just below the detection limit and some contain no pesticide at all. Examination of the distribution of samples in which the pesticide was detected will indicate if the assumption is reasonable. Another method is to omit non-detects entirely and make calculations using only the samples in which residues were found. This is usually the approach when only a few of the samples contain detected residues. A conservative approach is to include non-detects in calculations as if they had a concentration equivalent to the detection limit. This is frequently used when assessing maximum concentrations or exposure levels, and would probably be most appropriate in risk assessments.
When the detection limit is very low in comparison to the majority of the residue concentrations, deciding to include non-detects at the detection limit, at half the detection limit or even at 0 in calculations has little effect on the result. When the detection limit is high in comparison to the residue level, things get more complex, and how it might be handled depends on the purpose of the analyses.
Registration and tolerance enforcement methods are equally demanding
In our previous pesticide residue distribution scenario, what would we conclude if the tolerance was 5 ppm and the method detection limit was 4.5 ppm? We would still be able to see concentrations exceeding the tolerance. The pesticide concentrations in the study samples would be the same; however, we would have reported no residue detections in any of the samples. The tolerance and the detection limit are so close that the risk of samples exceeding the tolerance would not be evident. This is one case where pushing the detection limit to a lower level would definitely be worth the trouble. But, we could still use the method to find a tolerance violation, whether an excessive concentration or an unregistered use. Or could we?
Method detection limits represent the best performance consistently achievable from a method in a particular laboratory with a given set of instrumentation. Confidence in pesticide concentrations determined at or near the detection limit is generally adequate; it is confirmation of pesticide identity that is a problem. In a study of residues for a known application of a particular pesticide, confirmation of pesticide identity is usually not an issue. We know the pesticide was applied. It is no surprise to find it in samples, even at low levels. Generally, no other chemicals have been applied that will interfere with our analyses.
In commodity screens, the chemist rarely knows what was applied to the crop, and what interfering compounds might be present. If we find an instrumental response that we suspect is a particular pesticide, we can accurately determine the concentration if the compound is what we think it is. For tolerance violations, confirmation of identity is essential. I wouldn't care for my results to be used in a crop-destruct order unless I was sure of the data.
For methods relying on mass spectrometric (MS) detection, confirmation of identity is built into the method. The measured response is generated from diagnostic molecular mass fragments, providing detection and identification at the same time. For many pesticides, MS analysis is either not possible or is not as sensitive as other detectors. With other detectors, confirmation of identity requires use of at least one alternate detector and/or alternate chromatographic column. If we get the next best method out of our chemist's bag of tricks, the detection limit is usually 2 to 10 times less sensitive. If the enforcement level was close to the detection limit of our most sensitive method, there would be no alternate choice for confirmation.
Tolerance levels can thus be used to judge the adequacy of a method's detection limit, whether the method was intended to be used for pesticide registration or tolerance enforcement. In both cases, the method needs to be sensitive enough to detect concentrations below the tolerance, either to assess the probability of exceeding a tolerance from a particular application or to allow room for confirmation of pesticide identity.
The FQPA incentive
It has become increasingly important for analytical methods to achieve the lowest detection limits possible. For many pesticide and crop combinations, the majority of commodity analyses lead to non-detects. If concentrations in these samples are assumed to be at the detection limit for calculation of exposures, a gross overestimation of exposure can result. It has become crucial to know what is going on in the murky regions below previous detection limits. Finding no detected residues in samples at levels comfortably below an existing tolerance is no longer enough; for determination of aggregate exposures, data for actual residue levels regardless of their relationship to existing tolerances are best to use. When no residues are detectable, having the lowest detection limits possible reduces overestimations in risk assessments.
Efforts to achieve the best possible detection limits have generally been devoted to environmental and biological samples. The rules of the commodities game have changed, and life in the analytical laboratory is getting even more challenging. Commodities and pesticides that are difficult to analyze are at a distinct disadvantage. These will have higher detection levels, and could therefore be assumed to contain higher concentrations when actual residues cannot be determined. New pesticide chemistries are abounding, and new demands are being put on analysis of existing pesticides. Perhaps this pressure will spawn the next generation of detectors, and we will get a few new toys (as well as a few more headaches) in the lab.
Return to Table of Contents for the October 1998 issue
1999 Subscription ReminderThis is the time of year to start thinking about renewing your subscription for the 1999 Agrichemical and Environmental News. The subscription fee remains at $15 per year and will include 12 issues of fascinating information and riveting reading. Please make the check out to WSU, and mail it to Pesticide Information Center, WSU Tri-Cities, 2710 University Dr., Richland WA, 99352-1671. As before, the subscription fee merely covers the costs of printing and mailing the newsletter. Web access remains free; the URL is http://picol.cahe.wsu.edu. Don’t take too long to think about it though, as we must have your check by December 15, 1998 in order to mail you the January 1999 issue. If your check arrives after December 15, we will make all efforts to include you in the January mailing, but if you’re late we will only guarantee that you will begin 1999 with the February issue. If you have any questions or comments please direct them to Catherine Daniels at (509) 372-7495, or email cdaniels@tricity.wsu.edu. |
Return to Table of Contents for the October 1998 issue
WSU Recertification Courses offer 6 credits per day. Registration fee is $45 per day. Register early and save $15 per day. For information contact: Cooperative Extension Conferences: 509-335-2830 or pest@cahe.wsu.edu Information is also available on-line at: http://pep.wsu.edu
| Eastern Washington | Western Washington | ||
| Tacoma | November 19 & 20 | Okanogan | November 3 |
| Pasco | November 9 & 10 | ||
| Pasco (Spanish) | November 10 | ||
| Eastern Washington | Western Washington | ||
| Spokane | January 13 & 14 | Vancouver & PCO Workshop | January 6 & 7 |
| Yakima | January 21 & 22 | Tacoma | January 13 & 14 |
| Pasco | January 26 & 27 | Edmonds | January 21 & 22 |
| Moses Lake | January 28 & 29 | Port Orchard | January 28 & 29 |
| Pullman | February 3 & 4 | Olympia | February 1 & 2 |
| Wenatchee | February 17 & 18 | Highline | February 4 & 5 |
| Spokane (Agriculture) | February 19 | Mt. Vernon | February 10 & 11 |
| Seattle | March 4 & 5 | ||
| Bellingham Insect Workshop | March 12 | ||
Washington State University annually conducts pre-license training for pesticide applicators, consultants, and dealers. Washington State Department of Agriculture offers all exam categories at the end of the training. Anyone preparing for pesticide licensing exams will benefit from the training programs offered; however, this training will be most useful to those preparing for the following license exams:
| Eastern Washington | Western Washington | ||
| Spokane | January 12,13,14 | Vancouver | January 5,6,7 |
| Yakima | January 20,21,22 | Tacoma | January 12,13,14 |
| Pasco | January 25.26,28 | Mt. Vernon | February 9,10,11 |
| Moses Lake | January 28,29 | Tacoma | February 23,24,25 |
| Pullman | February 2,3,4 | Puyallup | March 23,24,25 |
| Wenatchee | February 16,17,18 | ||
| Richland | February 22 | Wenatchee | February 24 |
| Yakima | February 23 | Spokane | February 25 |
| PCO Workshop Vancouver | January 7 | Landscape Insect Workshop Bellingham | March 12 |
Return to Table of Contents for the October 1998 issue
Dr. Allan S. Felsot, Environmental Toxicologist, WSU
Perhaps a million dollars will be spent before all is said and done in implementing the Columbia Basin Ground Water Management Area (GWMA) (Tri-City Herald 1998). The GWMA is a coordinated local, state, and federal effort to manage ground water quality in Franklin, Grant, and Adams Counties. It was formed partly in reaction to the EPA proposal to designate the Columbia Plateau as a sole-source aquifer and thus bring increased federal regulation to the region. Focusing on nitrates in well water, GWMA will use the public funding for monitoring, education, and implementation of solutions to reduce contamination.
Preventing nitrates from leaching to ground water is ostensibly motivated by the need to protect public health. Nitrates in drinking water have been associated with isolated cases of methemoglobinemia (MHB). Commonly known as “blue-baby” syndrome, MHB affects infants under 6 months of age. The most characteristic symptom is an ashen, bluish (cyanotic) hue to the skin and nails.
The most commonly perceived risk factor for MHB is feeding infants powdered formulas diluted with well water containing excessive levels of nitrates. The presence of well water nitrate is commonly attributed to farming practices that have used excessive amounts of synthetic fertilizers over the last thirty years. Given these perceptions, altering agronomic management practices for nitrogen use will logically result in safer water.
The problem with this cause-and-effect scenario is that common perception may now be wrong, or at least so out-of-date as to put in place management practices that will fail to provide corresponding benefits in public health. Consider the following statement that appeared in a 1995 report (Nitrate and Nitrite in Drinking Water) from the National Research Council (NRC), the research arm of the National Academy of Sciences (NRC 1995). “Infection is the major contributor to methemoglobinemia from nitrate exposure; the incremental contribution of drinking water is negligible.” A bombshell of a statement, indeed, but very important if the GWMA is to implement appropriate solutions for protecting ground water quality that ultimately has tangible public health benefits.
The key to appropriate ground water management is buried in the NRC statement and the scientific literature behind it. Based on my review of this literature, I hypothesize that focusing solely on nitrates, as the GWMA plan now seems to do, will not benefit public health. Poorly constructed and located old wells and bacterial contamination are as much a cause of drinking water quality deterioration as are nitrates. I will develop this hypothesis further by reviewing briefly the historical linkage between nitrates and infant MHB, the alternative perspective expounded in the NRC report, and recent ground water monitoring studies useful for guiding the way to effective management that will protect public health.
Historical Concerns about Well Water Nitrates and Public Health
Nitrate is one of the few contaminants whose drinking water standard is solely derived from epidemiological studies. But the early studies, which date prior to 1950, were not broad scientific investigations. Rather, they were medical cases reported in the literature. Nevertheless, the current standard, 10 milligrams (mg) of nitrate-nitrogen (N) per liter (L) of water (or 44 mg/L of nitrate ion), was first proposed over 50 years ago, specifically to protect infants from MHB (NRC 1978).
Patient case observations by H. H. Comly, a young resident doctor at the University of Iowa, were the first to link infantile MHB with the consumption of well water containing high levels of nitrates (Comly 1945). By the early 1940's, methemoglobin, an aberrant form of the blood protein hemoglobin but lacking the capabability of transporting oxygen, was well known. Methemoglobin is a normal constituent of blood, but its level is kept low by an enzyme that rapidly changes it back into normal hemoglobin. Certain drugs, including those containing nitrate and the related ion, nitrite, were recognized as causing an excessive build up of methemoglobin leading to MHB. As a result, when the hemoglobin levels are too low, the skin and nails turn cyanotic.
During the late 1940's several other case reports echoed Comly's experiences (Bosch 1948, Walton 1951). An infant would be brought to an emergency room or clinic. The symptoms were usually the same as described by Comly, a bluish color perhaps with difficulty breathing or general lethargy. A normal color would return upon treatment with methylene blue, a dye that had been known to counteract the symptoms of MHB. The infant was sent home with parental directions to not use the well water. In many cases the water was tested and found to have excessive levels of nitrate.
By 1951, enough methemoglobinemia case reports had been published to put together a review (Walton 1951). Seventeen states had reported cases of water-induced infant MHB; no state reported cases when the nitrate-N concentration was less than 10 mg/L. Examination of the data gave validity to Comly's estimation that the upper limit for nitrate-N should be no higher than 10 mg/L. In 1962, the U.S. Public Health Service recommended a nitrate-N limit of 10 mg/L. In 1974, under authority of the Safe Drinking Water Act, the EPA adopted the same standard (Fan 1996).
Since first adoption of the nitrate standard, occasional medical case reports have linked nitrates in drinking water with infant MHB (Knotek 1964; Vigil 1965; Miller 1971; Shearer 1972; Super 1981; Johnson 1987). About 2000 cases of MHB with a mortality rate of 10% have been reported worldwide between 1945 and 1990 (Kross et al. 1992). In the U.S., however, cases reported from Minnesota, including deaths, still account for most of the reports. The NRC (1995) found no studies of nitrate-induced MHB since 1990. Water-induced MBH seems rather rare now, but a dearth of cases has been attributed primarily to a lack of reporting requirements, and secondarily to a lack of physician awareness.
An Alternative Hypothesis of the Relationship between Nitrates and MHB
The 1995 NRC report was a response to a request from the EPA for a review of the current basis of the drinking water standard for nitrate and to determine whether it remained protective of public health. The NRC concluded that limiting infant exposure to nitrate was a sensible public health measure, and given the current toxicological and epidemiological information, the 10 mg/L regulatory standard was adequate. However, the NRC pointed out that bacterial and viral infection, which can manifest as diarrhea, vomiting, and acidosis (abnormally low blood pH), are contributing factors to MHB, suggesting that nitrates are but one of several water quality parameters to consider.
What is striking about the historical case reports of MHB associated with nitrates in water, is how often the infants were reported to have diarrhea and sometimes vomiting (Comly 1945, Bosch et al. 1950, Vigil et al. 1965, Shearer et al. 1972, Johnson et al. 1987, Knobeloch et al. 1993). The high nitrate content of water was frequently associated with unacceptable levels of coliform bacterial contamination. Even when bacterial contamination was not reported, the wells were often described as shallow, improperly sealed, dug structures. The well locations were usually near a barnyard, septic system, cesspool, or outhouse (Bosch et al. 1950, Miller 1971).
Although no one disputes the hazard of high levels of nitrates to infants, numerous published cases have reported MHB in infants with diarrhea and acidosis but no exposure to water with elevated nitrate levels (Hegesh and Shiloah 1982, Bricker et al. 1983, Dagan et al. 1988, Smith et al. 1988, Lebby et al. 1993, Murray and Christie 1993, Gebara 1994, Hanukoglu and Danon 1996). Other studies, while not reporting whether water was a source of nitrates, have recognized that MHB may be commonly associated with diarrhea and acidosis (Danish 1983, Kay et al. 1990), and sometimes urinary tract infections (Hanukoglu et al. 1983). Other contaminants in water could also lead to MHB, confounding the role of nitrates. For example, a recent case of MHB in a Wisconsin infant was attributed to elevated copper levels (Knobeloch et al. 1993). The infant was symptomatic with vomiting and diarrhea, and the well water contained 10 mg/L nitrate-N after going through a treatment process known as reverse osmosis.
Why Would MHB Be Associated with Diarrhea?
By the 1960's, when the nitrate drinking water standard was developed, the formation of methemoglobin and the extraordinary susceptibility of infants was well known. Biochemical studies had shown that nitrite, not nitrate, interacted with hemoglobin to produce methemoglobin. Infants were susceptible because they lacked enough of an enzyme that commonly changes the methemoglobin back to its normal, oxygen carrying form. Infants under 6 months old also carried a form of hemoglobin that could be more easily affected by nitrite than older children and adults. Because the infant stomach was not nearly as acid as an adult stomach, nitrate-transforming bacteria thrived and changed the nitrate into nitrite.
In addition to formation in the stomach, nitrite is produced from nitrate in the salivary glands. Nitrate moves from the stomach into the small intestine where it is absorbed into the blood. As the blood circulates through the salivary glands, some of the nitrate is changed to nitrite and both ions are secreted into the mouth and are then swallowed again. About 5% of the total ingested nitrate is believed to be converted to nitrite (NRC 1995). Nitrate is not changed to nitrite in the blood.
Nitrite tends to pass out of the stomach more slowly than nitrate. It can be slowly absorbed from the intestine, but significant amounts are eliminated in the feces. During infection, however, the intestinal lining becomes irritated and inflamed, causing it to be more leaky to the nitrite. One study has shown that diarrhea speeds up the passage of nitrite from the stomach into the intestine (Witter et al. 1979). Thus, it is probable that digestive tract infections allow a lot more nitrite absorption into the blood than when the intestine is healthy.
Another reason that bacterial and viral infections of the digestive or urinary tract could be associated with the onset of MHB is also related to the body's ability to synthesize nitrate and nitrite (Green et al. 1981). If water nitrates are low, about 45% of the total nitrate exposure is due to this endogenous synthesis (NRC 1995). Studies in rodents have shown that bacterial infection causes an increase in nitrate and nitrite synthesis by specialized cells of the immune system (Wagner et al. 1983, Stuehr and Marletta 1985). The newly synthesized nitrite can be excreted into the blood by these cells and thus become available to bind with hemoglobin.
Incidence of Bacterial and Nitrate Contamination of Ground Water
The flurry of MHB case reports in the late 1940's occurred at a time when synthetic mineral nitrogen fertilizers were somewhat of a novelty. Synthetic fertilizer use did not start to increase until the end of the 1950's. Yet, the wells involved in the early MHB cases were highly contaminated with nitrates. Ironically, as annual synthetic fertilizer use increased from about 3 metric tons in 1960 to 10 metric tons by 1980 (Puckett 1995), the number of published MHB reports related to nitrates in well water diminished. Instead, the majority of reports seemed to be making a connection between the coincidence of infant diarrhea and MHB, suggesting that bacterial contamination may be just as important to manage as nitrate content.
Two recent ground water monitoring reports emphasize the widespread nature of bacterial contamination. A statewide survey of well water quality in Nebraska showed that 19% of rural wells were contaminated with greater than 10 mg/L nitrate-N, and 15% had bacterial contamination (Gosselin 1997). Wells contaminated with bacteria generally had low nitrate concentrations unless the wells were constructed of brick, concrete or tile rather than the more acceptable PVC plastic or steel.
A province-wide survey in Ontario, Canada showed 14% of drinking water wells with nitrate-N above 10 mg/L and 34% with unacceptable bacterial contamination (Goss et al. 1998). Bacterial contamination decreased with increasing distance of a well from feedlots or exercise yards on livestock farms. Monitoring wells installed inside agricultural fields still had significant levels of bacterial and nitrate contamination, which was attributed to application of manure (Rudolph et al. 1998).
Lessons Learned
Failure to thoroughly understand the nature of a public health problem can lead to failed attempts at management. A survey of newspaper articles indicates that growers tend to be the scapegoats for nitrate contamination and, by association, infantile MHB. Is it unreasonable to assume that the articles may reflect the attitudes of policy makers or at least influence them? Allowing policy to myopically focus on nitrates is causing hazards to be overlooked. Bacterial contamination can lead to infection, acidosis, diarrhea, and vomiting, known risk factors for MHB in infants. Surely, very high levels of nitrates in water are not desirable and increase the risk of MHB, but simply mandating reduced nitrogen inputs is a simplistic solution to a potential public health problem. By focusing only on nitrates, and ignoring potentially widespread bacterial contamination, poor well construction and undesirable locations, the GWMA may mollify the policy makers, but ultimately do little to protect public health.
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References:
Bosch, H. M., A. B. Rosenfield, R. Huston, H. R. Shipman, and F. L. Woodward. 1950. J. Am. Water Works Assoc. 42:161-170.
Bricker, T., L. S. Jefferson, and A. A. Mintz. 1983. J. of Pediatrics 102:161.
Comly, H. H. 1945. J. Am. Medical Associ. 129:112-116.
Dagan, R., F. Zaltastein, and Gorodischer. 1988. Eur. J. Pediatr. 147:87-89.
Danish, E. H. 1983. J. of Pediatrics 102:162-161.
Fan, A. M., and V. E. Steinberg. 1996. Regulatory Toxicol. and Pharmacol. 23:35-43.
Gebara, B. M., and M. G. Goetting. 1994. Clinical Pediatrics 370-373.
Goss, M. J., D. A. J. Rudolph, D. L. Barry. 1998. J. Contaminant Hydrology 32:267-293.
Gosselin, D. C., J. Headrick, R. Tremblay, X. -H Chen, and S. Summerside. 1997. Ground Water Monitoring and Remediation 17:77-87.
Green, L. C., K. R. De Luzuriaga, D. A. Wagner, W. Rand, N.Istfan, V. R. Young, and S. R. Tannenbaum. 1981.
Proc. Natl. Acad. Sci. USA 78:7764-7768.
Hanukoglu, A., and P. N. Danon. 1996. J. Pediatric Gastroenterology and Nutrition 23:1-7.
Hegesh, E., and J. Shiloah. 1982. Clinica Chemica Acta 125:107-115.
Johnson, C. J., P. A. Bonrud, T. L. Dosch, A. W. Senger, K. A. Busch, D. C. Kilness, and M. R. Meyer. 1987.
J. Am. Medical Assoc. 257:2796-2797.
Kay, M. A., W. O'Brien, B. Kessler, R. McVie, and E. R. B. McCabe. 1990. Pediatrics 85:589-592.
Knobeloch, L., K. Krenz, and H. Anderson. 1993. Morbidity and Mortality Weekly Report (MMWR) 42:217-219.
Knotek, Z., and P. Schmidt. 1964. Pediatrics 78-83.
Kross, B. C., A. Ayebo, and L. J. Fuortes. 1992. American Family Physician 46:183-188.
Lebby, T., J. J. Roco, and E. L. Arcinue. 1993. Am. J. Emergency Medicine 11:471-472.
Miller, L. W. 1971. J. Am. Medical Assoc. 216:1642-1643.
Murray, K. F., and D. L. Christie. 1993. Journal of Pediatrics 122:90-92.
National Research Council (NRC). 1995. Nitrate and nitrite in drinking water. National Academy Press, Washington D. C.63 pages.
Rudolph, D. L., D. A. J. Barry, and M. J. Goss. 1998. J. Contaminant Hydrology 32:295-311.
Shearer, L. A., J. R. Goldsmith, C. Young, O. A. Kearns, and B.R. Tamplin. 1972. American Journal of Public Health 62:1180.
Smith, M. A., N. Shah, J. S. Lobel, and W. Hamilton. 1988. Am.J. Pediatric Hematology/Oncology 10:35-38.
Stuehr, D. J., and M. A. Marletta. 1985. Proc. Natl. Acad. Sci. 82:7738-7742.
Super, M., H. De V. Heese, D. MacKenzie, W. S. Dempster, J.Du Plessis, and J. J. Ferreira. 1981. Water Research 15:1265-1270.
Vigil, J., S. Warburton, W. S. Haynes, and L. Kaiser. 1965.Public Health Reports 80:1119-1121.
Wagner, D. A., V. R. Young, and S. R. Tannenbaum. 1981. Proc. Natl. Acad. Sci. USA 80:4518-4521.
Walton, G. 1951. Am. J. Public Health 41:986-996.
Witter, J. P., S. J. Gatley, and E. Balish. 1979. Science 204:411-413.
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Dr. Allan S. Felsot, Environmental Toxicologist, WSU
The EPA had been promising to make its hazard assessments for pesticide registration decisions much more open to public view, especially since passage of the Food Quality Protection Act (FQPA). Perceiving that the organophosphate insecticides (OPs) contribute an inordinate amount of risk under the new FQPA mandates, the EPA assessment of this important group of compounds. The detailed full human health assessments for the first 16 OPs are now out of the closet. Known as the Human Health Assessment Reregistration Eligibility Decision Documents, they can be downloaded from the internet in Portable Document Format (PDF) at http://www.epa.gov/oppsrrd1/op/. The WEB site also posts two documents summarizing the preliminary finding for all the OPs. A short HTML file of frequently asked questions is included for each of the 16 OPs reviewed in detail thus far.
Hazard Assessment of the Organophosphates Report
If you can't wait for the full hazard assessments of all 40 OPs, you can get a reliable overview of what to expect from the Hazard Assessment of the Organophosphates Report, (http://www.epa.gov/oppsrrd1/op/hiarcfqp.pdf). Prepared by the Hazard Identification Assessment Review Committee (HIARC), the document evaluates each compound's potential for neurotoxic, developmental, and reproductive toxicity. The HIARC reviewed the following types of tests (dosing scheme shown in parentheses).
u Neurotoxicity
u Prenatal Developmental Toxicity
u Two-Generation Reproductive Toxicity
Although numerous toxicology tests are required, and dogs may be used in addition to rodents and rabbits, EPA's objectives, as reported in the overview report, focused only on tests that would give clues to potential enhanced susceptibility of infants and children. A second objective was to determine the completeness of the toxicological databases. Both the evidence of enhanced susceptibility and completeness of the database were used to make recommendations for uncertainty factors (i.e., safety factors). These factors are applied to the dose levels (per unit of body weight per day) where no effects are observed (the NOEL). The reference doses that result from division of the NOELs by the uncertainty factors represent the maximum acute (one dose) and chronic (multiple doses over a life-time) exposure with reasonable certainty of no adverse effect.
FQPA Safety Factor Recommendations
One of the provisions of the FQPA that has been very contentious is the EPA's mandate to adjust the reference doses by an extra ten-fold uncertainty factor if children are more susceptible than adults. Likewise, a greater uncertainty factor could be applied if critical data concerning developmental and reproductive effects are missing from the toxicological database. Application of this extra safety factor to the usual 100-fold uncertainty factor would greatly reduce the allowable exposure, possibly resulting in reduced tolerances, altered use patterns, and lower maximum application rates.
Infants and children are commonly perceived as being more susceptible to toxic effects of chemicals than adults. However, based on EPA's report FQPA Safety Factor Recommendations for the Organophosphates (http://www.epa.gov/oppsrrd1/op/hiarcfqp.pdf), 18 of the OPs will have no extra FQPA safety factors applied because the neurotoxicological, developmental, and reproductive studies indicated that offspring were not more sensitive than the adults. An extra three-fold FQPA safety factor will be applied to another 10 OPs, not because of enhanced susceptibility, but because required neurotoxicity studies are incomplete. Twelve OPs will retain the full 10-fold FQPA safety factor, either because of evidence from the scientific literature of potentially adverse neurodevelopmental effects, or because the database lacks the toxicological studies needed to properly assess hazards to children.
All of EPA's hazard assessments are preliminary and subject to public comment before a final decision is made. It is now clear that only a few of the OPs will likely be subjected to an extra 10-fold FQPA safety factor for protection of children. Future editions of AENews will carry more in-depth reports of the hazard assessments for individual OPs that are important to minor crop production.
Return to Table of Contents for the October 1998 issue
| Tolerance Information | ||||||
| Chemical | Federal | Tolerance | Commodity (raw) | Time-Limited | ||
| (type) | Register | (ppm) | Yes/No | New/Extension | Expiration Date | |
| buprofezin (insecticide) | 8/5/98 page 41720 | 0.50 | cucurbits | Yes | New | 12/31/99 |
| 0.70 | tomatoes | |||||
| 1.00 | tomato paste | |||||
| Comment: These time-limited tolerances are issued in response to EPA's granting Section 18s for use on cucurbits, to control whiteflies, in Arizona, and for the control of silverleaf whitefly on tomatoes in Florida. | ||||||
| fluroxypyr 1-methylheptyl ester | 8/5/98 page 41727 | 0.50 | wheat and barley, grain | Yes | New | 12/1/99 |
| (herbicide) | 12.00 | wheat, forage | ||||
| 20.00 | wheat and barley, hay | |||||
| 12.00 | wheat and barley, straw | |||||
| 0.60 | aspirated grain fractions | |||||
| 0.05 | corn, sweet, K + CWHR | |||||
| 2.00 | corn, sweet, forage | |||||
| 2.50 | corn, sweet, stover | |||||
| 0.05 | corn, field, grain | |||||
| 2.00 | corn, field, forage | |||||
| 2.50 | corn, field, stover | |||||
| 0.10 | meat, fat, and mbp (except kidney) of cattle, goats, hogs, horses, and sheep | |||||
| 0.50 | kidney of cattle, goats, hogs, horses, and sheep | |||||
| 0.10 | milk | |||||
| Comment: These time-limited tolerances are issued in response to EPA's granting Section 18's for use of fluroxypyr on wheat, barley, and corn to control volunteer potatoes in Oregon, Michigan, and Washington, and to control kochia in wheat and barley in the Dakotas. | ||||||
| avermectin (insecticide) | 8/7/98 page 42246 | 0.05 | spinach | Yes | Extension | 1/31/00 |
| Comment: This time-limited tolerance is issued in response to EPA granting a Section 18 for use of avermectin to control leafminer on spinach in California. | ||||||
| endothall (herbicide) | 8/7/98 page 42248 | 0.30 | canola seed | Yes | Extension | 2/29/00 |
| Comment: This time-limited tolerance is issued in response to EPA granting a Section 18 for the use of endothall to control smartweed and buckwheat in canola in Montana, Minnesota, and North Dakota. | ||||||
| carfentrazone-ethyl (herbicide) | 8/7/98 page 42240 | 0.20 | wheat, hay | Yes | Extension | 5/8/99 |
| 0.20 | wheat, straw | |||||
| 0.20 | wheat, grain | |||||
| 0.15 | corn, forage | |||||
| 0.15 | corn, fodder | |||||
| 0.15 | corn, grain | |||||
| Comment: These time-limited tolerances are issued in response to a request by FMC for an EUP. | ||||||
| potassium dihydrogen phosphate (fungicide) | 8/12/98 page 43083 | exempt | all food commodities | No | N/A | N/A |
| zucchini juice (inert ingredient) | 8/12/98 page 43085 | exempt | see comment | No | N/A | N/A |
| The exemption applies when zucchini juice is used as a source of the inert ingredient gustatory stimulant cucurbitain in pesticide formulations. | ||||||
| triasulfuron (herbicide) | 8/18/98 page 44146 | 0.50 | cattle, kidney | No | N/A | N/A |
| 0.50 | goat, kidney | |||||
| 7.00 | grass, forage | |||||
| 2.00 | grass, hay | |||||
| 0.50 | horse, kidney | |||||
| 0.50 | sheep, kidney | |||||
| phosphine (rodenticide) | 8/25/98 page 45176 | 0.10 | timothy; seed, forage, & hay | Yes | New | 2/1/00 |
| 0.10 | clover; forage & hay | |||||
| 0.10 | alfalfa; forage & hay | |||||
| Comment: These time-limited tolerances are issued in response to EPA's granting a Section 18 for the use of zinc phosphide on timothy, timothy-alfalfa, clover stands in Washington. | ||||||
| deltamethrin (insecticide) | 8/26/98 page 45406 | 0.05 | food/feed items | No | N/A | N/A |
| triclopyr (herbicide) | 8/26/98 page 45404 | 0.20 | fish | Yes | Extension | 6/30/00 |
| 5.00 | shellfish | |||||
| Comment: These time-limited tolerances are extended in response to EPA's granting Section 18's for the use of triclopyr to control purple loosestrife in aquatic sites in Minnesota and North Dakota. | ||||||
| Miscellaneous Information | ||||||
| On August 11, EPA announced it had established a screening program for determining which pesticides are endocrine disruptors. The major elements of the Endocrine Disruptor Screening Program are discussed in the Federal Register commencing on page 82452. Operational details, regulatory implementation, and an opportunity for public comment will be provided in a later Federal Register notice. (8/11/98 page 42849) | ||||||
| On August 12, EPA announced the availability for review of preliminary risk assessments for 9 organophosphates. The risk assessments themselves were not published; however, EPA has made these documents available on the web at URL http://www.epa.gov/oppsrrd1/op/index.htm. The compounds reviewed are: azinphos-methyl, bensulide, ethion, fenamiphos, isofenphos, naled, phorate, profenofos, and terbufos. Written comments on these preliminary risk assessments are due October 13, 1998. (8/12/98 page 43175) | ||||||
| In the August 14,1998, Federal Register, the Grain Inspection, Packers and Stockyards Administration (GIPSA) announced that it would be reviewing the US Standards for Sorghum contained in Subpart I of 7 CFR part 180. GIPSA is inviting any comments or suggestion including those concerning the classification of sorghum or the definition of sorghum, broken kernels, foreign material, or damaged kernels. Comments are due October 13, 1998. (8/14/98 page 43641) | ||||||
Return to Table of Contents for the October 1998 issue
The PNN is operated by WSU's Pesticide Information Center for the Washington State Commission on Pesticide Registration. The PNN system is designed to distribute pesticide registration and label change information to groups representing Washington's pesticide users. The material below is a summary of the information distributed on the PNN in the past month.
Our office operates a web page called PICOL (Pesticide Information Center On-Line). This provides a label database, status on registrations and other related information. PICOL can be accessed at http://picol.cahe.wsu.edu or call our office, (509) 372-7492, for more information.
Federal Issues
Manufacturers Use Deletions
In the July 30 Federal Register, EPA announced that it had received a request from BASF Corporation to delete stone fruit and strawberry uses from its vinclozolin registrations. BASF is requesting this use deletion in response to decisions made as part of EPA's reregistration review. BASF currently has three vinclozolin products registered in Washington for use on stone fruit and strawberries. The products are: Ronilan FL, Ronilan DF, and Ronilan EG.
EPA proposes to accept BASF's request to amend its vinclozolin registration to terminate these uses and at BASF's request, EPA has waived the standard 180-day comment period. The notice of cancellation was published to allow affected parties to either convince BASF to maintain the desired use or to register the product themselves. In this notice EPA is also proposing 4 existing stock provisions. These are:
1) Commencing on the date the use termination becomes effective, no vinclozolin products may be released for shipment containing labels that allow for use on stone fruit and strawberries.
2) On that same date, any product not yet release for shipment may be stickered by BASF to reflect these use terminations.
3) Retailers, distributors, and end-users may sell, distribute, and use products containing the previously approved labeling until January 30, 2000.
4) Within 30 days of use termination BASF will provide all Ronilan points of purchase copies of a bulletin that details the label amendments and existing stock provisions.
In the July 8 Federal Register, EPA announced that it had received a request from Valent to delete pasture and rangeland uses from its insecticide Orthene Turf, Tree, & Ornamental WSP. Unless this request is withdrawn, these use deletions will become effective January 4, 1999. Anyone interested in retaining these uses should contact Valent before January 4, 1999.
In the July 8 Federal Register, EPA announced that it had received requests from three registrants to delete cranberries from three product labels. The products are: Furadan 15G (FMC), Pyrellin EC (Webb Wright), and Rotenone 5 Organic Insecticide (Bonide). Unless these requests are withdrawn, the cranberry use deletions will become effective January 4, 1999. Anyone interested in retaining these uses should contact the specific product registrant before January 4, 1999.
In the August 5 Federal Register, EPA announced that it had received a request from Bayer to delete lettuce as a usage site from the label for its insecticide Di-Syston 15% Granular. Unless this request is withdrawn, this use deletion will become effective February 1, 1999. Anyone interested in continued use of Di-Syston 15% Granular on lettuce should contact Bayer before February 1, 1999.
Section 18 Specific Exemptions
On August 4, EPA issued a Section 18 specific exemption for the use of Rally 40W to control powdery mildew in U-Pick and the Redcrest variety of strawberries. The exemption allows for treating 300 acres and expires June 24, 1999. The exemption was amended by EPA on August 5 to add the following rotational crop restrictions:
1) Strawberry fields treated with Rally 40W can be rotated at any time to crops included on the Rally 40 W label.
2) Strawberry fields treated with Rally 40W may be rotated to crops not included on the Rally 40W label if the following delays are observed: Leafy vegetables and small grains - 120 days; Root vegetables and all other crops - 210 days.
On July 23, EPA issued a specific exemption for the use of Hacco's Zinc Phosphide Oat Bait to control meadow voles in timothy, timothy/alfalfa, timothy/clover hay as well as in timothy seed crops. The exemption allows for use on 31,000 dormant acres in Kittitas County and it expires July 23, 1999.
Supplemental Labels and Use recommendations
Micro Flo has issued a use recommendation for its fungicide Captec 4L. The use recommendation provides product dilution instructions for use on apples grown in the pacific northwest.
State Issues
New Registrations
WSDA has issued a registration to Loveland Industries for its insecticide Prozap Dust'R. This product is registered for use on beef and dairy cattle, poultry and poultry buildings, and swine to control face flies, horn flies, lice, and mites.
WSDA has issued a registration to Loveland Industries for its insecticide Prozap LD-44Z Farm Insect Fogger. This product is registered for use on the following PNN-related sites: beef cattle, dairy cattle, dairy building, non-dairy livestock building, poultry building/yard, and swine.
WSDA has issued a registration to Loveland Industries for its insecticide Prozap Zipcide Dust. This product is registered for use on beef and dairy cattle for the control of horn fly and lice.
WSDA has issued a registration to Amrep/MBL Inc. for its herbicide Misty Weedtrol VF. Along with other sites, this product is registered for use to control marginal, floating, and submerged weeds in aquatic sites.
WSDA has issued a registration to American International Chemical for its fungicide Copper Sulfate Large Crystals. This product is registered for use on the following PNN-related sites: apricot, aquatic site, cherry, nectarine, peach, walnut, and flower. In addition to registering the main label, American International Chemical has also issued a supplemental label providing chemigation instructions for this product.
Section 24c Registrations
On August 5, WSDA issued an SLN, WA-980026, to Helena Chemical for the use of its insecticide Omni Supreme Oil for the control of powdery mildew on hops. This is a “me-too” registration similar to WA-980022 and WA-980023 for JMS Stylet Oil and Superior Spray Oil N.W. This SLN expires December 31, 1998.
On August 6, WSDA issued a Section 24c SLN registration, WA-980028, to Micro Flo for the use of its insecticide Endosulfan 3EC, through chemigation, to control Colorado potato beetle, armyworms, and aphids on potatoes. This is a “me-too” registration similar to WA-980017 issued for Drexel Endosulfan 3EC and WA-900023 issued to FMC for Thiodan 3EC. This SLN expires December 31, 1998.
On August 11, WSDA issued an SLN, WA-980030, to Brandt Consolidated for the use of its product Saf-T-Side to control mites and powdery mildew on hops. This is a “me-too” registration, similar to WA-980022, WA-980023, and WA-980026. This registration expires December 31, 1998.
On August 6, WSDA issued an SLN, WA-980027 to Micro Flo for the use of its insecticide Endosulfan 3EC to control spotted alfalfa aphid in alfalfa grown for seed. This is a “me-too” registration, similar to WA-980012 issued for the use of Drexel's Endosulfan 3EC, and WA-880012 issued to FMC for the use of Thiodan 3EC. This SLN will expire December 31, 1998.
Section 24c Revisions
On August 10, 1998, WSDA issued a revision to SLN WA-910032. This SLN had previously been issued to Sandoz for the use of its herbicide Banvel on fall or spring seeded wheat. The revisions include altering the waiting period for harvest from 10 to 14 days to read 14 days, adding a wind caution statement, and changing the EPA registration number (Banvel is now registered by BASF).
On August 10, 1998, WSDA issued a revision to SLN WA-960037. This SLN had previously been issued to Gowan for the use of its fungicide Botran 5F for the control of white mold on potatoes. The changes include the addition of a storage and disposal statement, a notice of conditions of sale statement, and the inclusion of an emergency medical response phone number.
Miscellaneous Regulatory Information
In August the PNN also distributed a message from WSDA requesting information on uses of organophosphates critical to Washington agriculture.
This page has been accessed
times since September 29, 1998.
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