PESTICIDE MANAGEMENT PLAN COMMITTEE
July, 23, 2013
Room B149 Orville Freeman Building, Saint Paul, MN
PMPC members in attendance:
PMPC Members not in attendance: Dick Rossman - Minnesota Department of Natural Resources.
Welcome and Introductions
Joe Zachmann, Minnesota Department of Agriculture (MDA) welcomed the participants, reviewed the agenda and the Pesticide Management Plan (PMP) objectives. He reminded the Pesticide Management Plan Committee (PMPC) members that the Commissioner welcomes questions and encourages interaction amongst this diverse group during the meeting.
All committee documents and presentations (those given and those planned but not given) are posted on the Pesticide Management Plan web page
2012 Monitoring: When, Where and How
Presentation: Bill Van Ryswyk, MDA
The MDA’s water monitoring uses new LC-MS/MS, GC-MS/MS, GC-MS analytical methods for its monitoring program. General information related to the 2012 groundwater and surface water monitoring work-plan components and progress were reviewed. The MDA analyzed 127 pesticide analytes in 2012.
The details of the ground water and surface monitoring sites, precipitation monitoring, glyphosate monitoring and special root river water shed special project were discussed. The committee lauded the MDA monitoring efforts and discussed issues related to precipitation monitoring, frequency of sampling and possibility of modifications of Pesticide Monitoring Regions (PMR) based on detections etc.
A committee member suggested that PMRs should be restructured according to the maximum and frequency of pesticide detections. The MDA explained that restructuring will not benefit because PRs are based on several factors including topography, soil type, climate, water resources etc.
Review of 2012 Monitoring Data
Presentation: Joe Zachmann, MDA
Joe Zachmann, MDA, led the review of the “Summary of 2012 Pesticide Detections in Groundwater and Surface Water Resources.” The summary focused on surface water “pesticides of concern” and groundwater “common detection pesticides,”
Committee discussion of the review included:
Ground water monitoring
It was found that degradates were major drivers for ground water sampling rather than parent compound. For example acetochlor parent was detected very infrequently as compared to acetochlor oxa.
A committee member enquired about the reasons for neonicotinoid detections in the ground water. The MDA explained that neonicotinoid detections are much below the bench mark values and are not of concern in Minnesota ground water. Neonicotinoids started showing up in water samples because of upgraded and efficient laboratory capabilities of the MDA. The MDA explained that neonicotinoid are used in Minnesota both for agricultural and urban usage and thus may be a reason for detections.
Acetochlor ESA was the primary form of acetochlor detections in ground water. No form of acetochlor exceeded available health based standards in 2012 in any of the PMRs. With an exception of PMR 5, acetochlor or acetochlor degradate median concentrations were below limits of detection.
A committee member raised questions about the maximum value (8.2 µg/L) of acetochlor ESA in PMR 8. The MDA explained that values are still very low and are more than 100 times below the available risk levels. The maximum value is still below 75th percentile and thus presents no concerns for human health.
A committee member suggested for looking reasons for high value in one particular well if that particular well was compromised and also suggested to present data in alternate form which could emphasize that detected values are much below the detection limits.
Another committee member enquired if acetochlor BMPs were concentrated in specific PMRs where there were high detections. The MDA explained that acetochlor BMPs were more concentrated in PMR 8 and 5 which showed maximum acetochlor values or increasing trend.
Alachlor detections showed decreasing trend and no form of alachlor exceeded available health based standards in 2012. Alachlor is not used much anymore and whatever detections are seen are probably from its use in previous years.
Atrazine and atrazine degradates were below available health based standards in 2012. Parent compound, atrazine and the degradate desethylatrazine were the drivers for detections in 2012. With an exception of PMR 5 and 9 median concentrations of atrazine and atrazine degradates were below detection limits.
A committee member suggested that cropping pattern maps may be included along with detections for making correlations. The MDA suggested that it will consider including hot links for cropping patterns in the report next year.
No form of dimethanamid exceeded available health based standards in 2012 and it will no more be a pesticide of concern. The MDH informed that guidance values for dimethanamid will be corrected this year.
No form of metalachlor exceeded available health based standards in 2012. Several PMRs showed upward trend for metolachlor forms. Detection frequency of all forms of metolachlor varied between all PMRs.
In 2012, metribuzin or metribuzin degradates were detected in PMR 4 only and did not exceed available health based standards. PMR 4 showed metribuzin detections probably because of soybean and potato dominance in PMR 4. Atrazine is not labeled for use in these two crops.
Deeper wells had similar concentrations as previous years. The concentrations between deeper and shallow wells are unpredictable with deeper wells frequently having higher concentrations than shallow wells.
Detection frequencies and concentrations were low for majority of compounds in urban groundwater. MCPP and Diuron were detected solely in urban areas.
PMR 4 and 9 had the highest percent detection at concentrations exceeding the MDH health risk limits for nitrate. Nitrate-nitrogen ratios commonly exceeded the MDH health risk limits in agricultural settings in Minnesota.
Surface Water Monitoring
The MDA monitors surface water in tiered structure. In 2012, 213, 144, 167 pesticide samples were collected at tier 1, 2 and 3 levels, respectively. Results were discussed separately for each tier system. Sixteen samples had concentrations greater than the chronic aquatic life standard for acetochlor and chlorpyrifos. Detections of three organophosphate insecticides (dichlorvos, malathion and terbufos) were above or very near chronic reference values. A single detection of 2,4-D and imidicloprid exceeded 50 percent of the applicable reference values at two different urban locations. Atrazine was detected above 50 percent of the 30-day human health standard at two different locations. For most parts chlorpyrifos detections were sporadic and not related to storms.
MCPA gave brief overview of STID sapling sites and methods and discussed interrelationship stressor ID and impairment.
Targeted Township Domestic well sampling
Presentation; Joe Zachmann
The MDA discussed a voluntary program “targeted township domestic well sampling program” for collecting water samples from urban areas and briefed about the progress and bottlenecks of the program.. Committee members discussed about the sampling procedures, methods, location, well structure, duration of program, farmer participation etc..
Acetochlor Impairment Response updates
Presentation: Larry Van Lieshout
The MDA informed that there were no acetochlor water quality standard violations since 2005 probably because growers are using lower rates of acetochlor and following BMPs. The MDA will continue to monitor waters in future years and work with MCPA on listing and delisting of impaired waters.
Chlorpyrifos draft impairment listing and BMPs
Presentation: Larry Van Lieshout
Chlorpyrifos is a listed as a pesticide of concern in because of its repeated detections and associated concentrations in Minnesota waters. The MDA is developing a water quality best management practices for chlorpyrifos. MCPA proposed listing seven mile creek as impaired.
U.S. EPA has not yet approved it.
Monitoring workplan for 2013
Presentation: John Hines
The MDA briefed about the changes in methods of detection limits for 2013 monitoring data. Reporting limits will be down for most of the pesticides and may need alternate analysis methods. However reporting limits will remain same for some of the important compounds such as chlorpyrifos and desethylatrazine. The MDA will be using ND instead of P for future reporting. The committee discussed merits and demerits of this approach.
A committee member suggested constructing a technical advisory committee for solving method and statistical issues.
Pesticide program updates
Presentation: Joe Zachmann
The MDA presented updates on other activities taken up by the MDA. These activities included special registration review, publishing bedbug control guide, pollinator habitat management.
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