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2002 Minutes |
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W-45 Technical Meeting Riverside, California, USDA-ARS, Salinity Laboratory, June 9-11, 2002 Attendance: Kevin Armbrust, Steve Aust, J. Gan, Cathleen Hapeman, Jeff Jenkins, Robert Krieger, Linda Lee, Ann Lemley, Qing Li, Glenn Miller, Sharon Papiernik, Ron Pardini, Chris Pritsos, Josef Seifert, Tracy Sterling, Barry Wilson. Guests: Staci Simonich Welcome and introduction: Pritsos welcomed the group, and thanked Sharon for hosting the meeting. Administrative Advisor, Ron Pardini, spoke about new resources for research such as the farm bill and homeland security issues. USDA has the homeland security grants available for food security work. Each State is supposed to have facilities for security. Pardini talked about the Impact Report. The Western group has the report as “Best of the West”. He encouraged having a collective impact report from this committee. The group discussed the support from the w-45 allocation in different States. Each representative shares the arrangement of grant uses in their institute. The websites are:
Jenkins updated the joint meeting with W-82. We need to have a clear goal to have a joint meeting with W-82. The group discussed the issues for discussion when we meet with W-82. Many objectives of W-45 and W-82 are overlapped. The meeting can help to clarify the objectives of the two projects. Pardini suggested having a liaison(s) to meet. The date (January) is a problem for some members, conflicting with teaching. Jenkins will contact with W-82 and inform W-82 that arranging a formal meeting with W-82 cannot work out at this time due to many conflicts. The group will select several liaisons from W-45 to attend W-82 meeting to present W-45 projects which are interests to W-82. This will be stated in the minutes. This is approved by consensus. Report review and critique: The group presented and critiqued technical reports as per usual. Simonich gave a nice presentation of her past, current and future research. Old and new business: New members: Collaborations:
Other ongoing interactions include the participation of Gan, Aust, Hapeman, Papiernik and Lemley in an upcoming ACS Div. of Environmental Chemistry Symposium. It was discussed and agreed that collaborations between Aust and other W45ers interested in pesticide runoff issues should be a priority for the group. Collective impact report: Extension: Extension is represented in the group through Kreiger, Jenkins, Lemley and Gan. Next meeting: Pritsos gave a final note of thanks to Sharon Papiernik for hosting a wonderful dinner for the group the night before and to Sharon Papiernik and Bob Kreiger for hosting the meeting. The meeting was adjourned at 11:45 AM, June 12, 2002. Subcommittee Assignments and Reviews Each subcommittee will review their assigned projects on Sunday evening. The underlined person is responsible for leading the discussion on Sunday and for writing and presenting the subcommittee’s project review on Monday. On Monday, each project leader will be allotted 5 minutes for a verbal introduction of the research being reported, the review subcommittee will be allotted 15 minutes for questions and critique. Ten minutes will then be allotted for open discussion and questions about each project. Please be sure to provide you written review on disk to Qing Li before you depart. As previously discussed, the Reports and Reviews should reflect a high regard for Clarity, Scientific Merit/Quality and Collaboration with other W-45 members. The summary of principle accomplishments must be understandable to the lay community and useful to administrators and policy makers. Group Reviewers Reports to Review
Please Note: First person listed as reviewer is responsible for first report to be reviewed by review team, second person listed as reviewer is responsible for second report to be reviewed and so on. Project Review and Critique:
The project is a continuation of studies on methods to reduce runoff, soil loss, pesticide load and toxicity from vegetable cultivation practices utilizing plastic mulch. Vegetative buffer strips of cereal rye between rows of plastic mulch were investigated. Cereal rye was chosen as it establishes quickly, withstands traffic, and dies off in summer heat, before it competes with the crop for moisture. Vegetable producers prefer plastic mulch even though it results in higher runoff with pesticide loads that are 3 to 25 times greater than with a vegetative mulch. Soil erosion with associated copper hydroxide, suspected to be toxic to the ecosystem, is 2 times greater with no vegetative buffer zone. In this study, metribuzin, esfenvalerate, endosulfan, chlorothalonil and copper, at 42, 3, 56, 190 and 129 mg/m2, respectively, were applied. Trickle irrigation, containing urea, was used during dry conditions. Runoff resulting from rain was monitored every 5 minutes as flow rate and total flow. Runoff from bare soil between tomato rows was 2-10 fold that from cereal rye furrows. Soil loss was nearly 10X higher. Total load loss for particulate phase copper was 2-4 times greater. Dissolved copper load was 2-10 times that of the particulate phase. Runoff data were extremely variable, due to rain events. Some rain events seem drastic as almost 2 tons of soil were lost per hectare due to two rain events, only 6 days apart. Soil loss was 10 fold less for the cereal rye cover. Copper load was much less with the cereal rye cover but not significantly when runoff was extreme. The concentration of copper in the runoff was thus much higher in runoff from the rye cover when runoff was high. Comments: Unfortunately no statistics were provided, and some results were difficult to analyze, such as toxicity to newly hatched grass shrimp larvae. But the report contained very extensive vegetable production data. Better production was observed on some days but not others but totals were identical. The toxicity data don’t lend themselves very well to analysis. The data are variable and confusing as toxicity decreases and then increases with increasing dilution. But the conclusion was that toxicity was less for runoff from cereal rye buffers. This is difficult to see and no statistical analyses were provided. A review of the literature on the effect of vegetative buffer zones would be helpful as these have been studied rather extensively. A statement as to the need for further research on this subject as applicable to vegetable growers that use plastic mulch would help demonstrate the need or significance of the research. The figure legends were sometimes incomplete or otherwise difficult to analyze. The species used in toxicity studies needs to be included in the abstract. The work planned for next year seems very appropriate because significant runoff into estuaries seems very evident. Otherwise the report reflects excellent work on a significant potential problem for which a practical and effective solution is suggested. Oregon Project Leader: J. Jenkins Reviewer Team: Wilson, Aust, Krieger and Pardini Summary: Methods of sampling, storage and analysis of runoff from agricultrual spraying of Guthion (azinphos-methyl) are reported presumably as a preclude to studies of the toxicity of the residues to wild salmonid populations. Clarity: The report is claearly and simply written. One criticism is that the lengthy discussion of methodology and its improvement is not accompanied by data demonstrating their statements. The data presented are probably sub-toxic levels found in the field tests. Scientific Merit: The project is of high quality and seems of high quality, even in the absence of data germane to the methodology development. Collaborations: Although many collaborators are mentioned, work with members of W45 are not. Layman's Useful Findings for Administrators: The improvement in analytical techniques, replacing non-detects with numerical values and variances, will be of important to risk assessment of runoff and realistic setting of pesticide residue levels. A cautionary note: Underlying this study (and others too) is the idea that pesticide runoff levels contribute to the decline in numbers of fish, in this case salmonids. But, the pesticide levels presented in the report are low, perhaps too low to adversely affect the fish. Other possibilities to keep in mind are that there may be high levels of the pesticide in streams where reproduction occurs and the fish hatch, there may be chronic accumulated effects of the pesticide, or that more than one agent may be involved.
The USDA Riverside project was well written, technically well done and, most important, interesting and useful. The review committee was particularly impressed with the productivity of the P.I. in terms of publications on a variety of areas important to W-45 members. We suggest a small formatting change for the report- use page numbers. Specific comments:
The Davis Project is to be commended for a very thorough comparison of methods for ACHE determination. There were a few questions we would like to be clarified. When using the Sigma products for the standardization, what is left of the kit contents. How was normalization accomplished? Results showed the kits were not consistent over temperature. How were the different temperatures achieved. How could the kits be improved? What is the future of ACHE testing and the application of this product? California – UC Riverside Project Leader: J. Gan Reviewer Team: A. Lemley (Primary), G. Miller, T. Sterling, J. Seifert The team would like to compliment the researcher on the choice of an important topic and the development of well-designed experiments. The runoff from nurseries is an potential source of water contamination, and the study of distribution of pesticides between soil particles and water in this venue is an appropriate and useful approach. The review team has several questions and comments to clarify the work for others.
New Mexico – NMSU Project Leader: T.M. Sterling Reviewer Team: Li, Papiernik, Pritsos This report describes the experimental determination of the genetic mechanisms of the resistance to the auxinic herbicides picloram and clopyralid by yellow starthistle weed (Centaurea solstitialis L.). The resistant phenotype is recessive and conferred by a single nuclear gene. The review group recognized that it is important to identify the mechanisms of herbicide resistance. The information will have direct implementation value to the best management practices of herbicide application and weed control. The experimental design was clear. This is an interesting project. However, the review group has the following comments and questions.
Page 2: Is the statement of “BAH is a stable product because of its extremely slow reaction rate with BIC” correct? Table 1: Is the soil series information in Table1 available? Indiana – Purdue University Project Leader: L.S. Lee Reviewer Team: Li, Papiernik, Pritsos This report presents degradation and formation of N,N’-dibutylurea, a conversion product from the fungicide Benomyl breakdown, in soils. The formation experiments were conducted by applying n-butyl isocyanate to soil. However, the formation of N,N’-dibutylurea from n-butyl isocyanate was not observed under the experimental conditions. Therefore, if N,N’-dibutylurea is found in soils, it is most liely from application of N,N’-dibutylurea-containing Benomyl formulation. N,N’-Dibutylurea degradation was primarily microbial and relatively fast (90% degraded in 6 weeks) The degradation was affected by a combination of at least two of the following factors: high clay content (>40%), dry condition, high pH, and high temperature. Specific comments and questions: Page 2: Explain the statement of “BAH is a stable product because of its extremely slow reaction rate with BIC.” Table 1: Is the soil series information in Table1 available? Utah – Utah State University Project Leader: Steve Aust Reviewer Team: Sharon Papiernik (Primary), Chris Pritsos, Qing Li The review committee commends Dr. Aust on his excellent report, which was clear and concise. The committee particularly noted that the experiments, which had a relatively simple design, provided very important information for the understanding of the mechanism of degradation of recalcitrant organic compounds by wood-rotting fungi. The committee has several questions for clarification and further information:
Reported is an analysis of products for pesticide cleaning products for fruits and vegetables compared to water rinse. Were companies approached to explain their claims and how they were substantiated? Such as claims made in P&G brochure?
Results and Discussion, 5th paragraph: water and Fit are not significantly different, but Fit residues were lower? This seems conflicting. What are the standard deviations of the measurements? What are the US EPA tolerances? This would be useful in data interpretation. Knowledge of crops used in the study would be useful for data interpretation and evaluation of the potential for extrapolation to other crops. What is the ability of different crops to “trap” pesticides – ie waxed apples and cucumbers vs. lettuce. As a limited number of pesticides were evaluated (2), can the results be compared to the 10 compounds used in P&G study. Were Captan and Methomyl used in the P&G study? What crop does P&G base its claim on and is it the same as yours? Is it bad if consumers feel that they are able to eat “non-organic” foods if they are “cleaned”? Is it significant that Fit removes more wax than water rinse? New York – Cornell University Project Leader: A. Lemley Reviewer Team: Jenkins, Simonich, Gan, Armbrust, Hapeman Reported is the continuation of research on the feasibility of ion exchange anodic Fenton treatment (membrane AFT) for the treatment of pesticide wastewater. Reported here is further refinement of methods reported in previous W-45 reports. Method development using 2,4 D as the substrate is further validated in this report using the insecticide carbaryl. The research goal is to improve the laboratory method’s applicability to use in the field. We commend Ann on her determination to move closer a practical application of the Fenton treatment for remediation of pesticides. We would like to see a brief discussion of model. The purpose of HPLC and GC/MS analysis is unclear. Should consider treatment efficiency per unit energy input, as well as Fenton reagent used. Pg 4 second paragraph, what about the gradient? Pg 4, third paragraph, “Because it is advisable” is unclear as a for optimal NaCl concentrations. Degradation products, need chromatogram proportion of products. Is what is generated better than the starting material. How will it be disposed of. How were peaks ID, spectral library, standards. Figure 3. What curve fit used for each data set? Carbaryl stable at acidic pH. But will Catylase may be a better quench agent than methanol because degrades residual peroxide. What about scale up. Competitive reactions with pesticide formulation and spray tank additives. Have you considered collaboration with W-45 microbiologist? Hawaii – University of Hawaii Project Leader: Q. Li Reviewer Team: Gan, Simonich, Jenkins, Armbrust Reports on new immunoassay for imidacloprid. Do other methods exist? The report is standalone and concise. Need compare analysis and cost with existing HPLC and GC methods. What is sensitivity of detection compared to existing HPLC and GC methods. Matrix interference with coffee appears to be a significant limitation. Need to characterize magnitude of interference by statistical analysis comparing dilutions. How does IC50 of 0.4 ppb value compare to other compounds. Has method been applied to real (aged) samples? Has immunoassay method sensitivity and selectivity been compared to existing (LC-MS) methods. Barry: ACh receptors? Hawaii – University of Hawaii Project Leader: J. Seifert Reviewer Team: Armbrust, Gan, Simonich, Jenkins Reported is a teratogenicity study of imidacloprid using chicken embryo. The premise is solid based on data available on organophosphates. The study is also timely. Generally the study is straightforward, however brief and lacking in detail. For example, results and discussion is only one paragraph. Comparison with OPs would be useful. Would be interesting to test Imidacloprid degradation product 4-chloronicotinic acid this procedure. Is there registrant data on teratogenicity in rats or mice? |
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