2016 ACS Conference

252nd American Chemical Society National Meeting & Exposition

252nd American Chemical Society National Meeting & Exposition

Location:Philadelphia, PA

Dates:August 21-25, 2016

The 252nd ACS National Meeting AGRO division and all business and social events will be held at the Loews Philadelphia Hotel. Waterborne always carves out plenty of time to prepare for this exceptional event. This year we have several presentations on our crop protection and home and personal care product work. Below is our 2016 presentation and poster line-up, along with their respective abstracts. We do our best to make presentations available for download after the conference while honoring client guidance on dissemination. If you have questions about any of these presentations, please contact Casey Wisch at wischc@waterborne-env.com.

Waterborne experts are chairing several sessions this year, all to be held at the Loews Philadelphia Hotel. Catch these great sessions here:

  • Gregg Hancock, Lead Scientist & Ecotoxicologist, is chairing, “Agrochemicals & Pollinators: Current Science & Risk Assessment Approaches“, on Tuesday, August 23, from 8:35 am – 11:10 am in Commonwealth Hall C
  • Amy Ritter, Principal Water Resources Engineer, Exposure Modeling & Risk Assessment, is chairing, “Subsurface Fate of Pesticides“, on Thursday, August 25, from 8:25 am – 11:50 am in Commonwealth Hall A2
  • Chris Holmes, Vice President & Principal Geographer, Environmental Risk Assessment, is chairing, “Environmental Risk Assessment of Down-the-Drain Chemicals“, on Thursday, August 25, from 8:50 am – 3:25 pm in Commonwealth Hall A1

The full 2016 ACS technical program can be found here>>

Waterborne's Presentations & Posters

Crop ProtectionPresentations

ENASGIPS – Implications of User’s Choices

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  • Session title: Terrestrial Field Dissipation Studies
  • Presentation type: Presentation
  • Presentation room: Commonwealth Hall A2 at 11:45AM
  • Presentation date: Sunday, August 21, 2016
  • Presenting Author: Gerco Hoogeweg

OECD’s ENASGIPS tool a module in the new harmonized terrestrial field dissipation guidelines (as of January 2016). It is a GIS based application that enables users to quickly determine if test sites located in a particular ecoregion have similar ecoregions elsewhere in Europe or North America. By demonstrating similarity it may not be required to conduct additional studies to achieve registration. ENASGIPS uses long-term annual total rainfall, average precipitation, soil texture, soil pH and soil organic matter to calculate a similarity index in a hollistic approach. As not all listed parameters may influence a pesticide’s behavior in the soil, a weight-of-evidence approach in which the user selects just the parameters that affect their pesticide can be used as well. The selection of just a few variables has a significant impact on the results, and therefore defining the conceptual model of the pesticide’s behavior is critical.

ENASGIPS can also be used by non-GIS experts to quickly select locations based on given set of selection criteria. The site selection module in ENASGIPS will do this. Executing the site selection tool is easy, however selecting the ranges to determine which areas adhere to are not. The input ranges change based on the question ask and how strict a user wants to be.

In this presentation we shall focus on the implication of choices users can make when using the ENAGIPS tool to determine similar ecoregions and to select sites.

Gerco Hoogeweg*, Nick Guth, Megan Sebasky (Waterborne Environmental). “ENASGIPS – Implications of User’s Choices”. Presentation. ACS 2016.

Home & Personal Care ProductsPresentations

Ecological Exposure Assessment Approaches for Indoor Use Pyrethroids in POTW Effluent

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  • Session title: Environmental Risk Assessment of Down-the-Drain Chemicals
  • Presentation type: Presentation
  • Presentation room: Commonwealth Hall A1 at 2:35PM
  • Presentation date: Thursday, August 25, 2016
  • Presenting Author: Chris Holmes

Indoor use pesticides are regulated for potential environmental impacts after movement down the drain and eventual release from publicly owned treatment works (POTWs). Pyrethroids are commonly used within the home for applications such as general household insect control (including ants, cockroaches, fleas and bedbugs) by both professional and homeowner application, for houseplant protection, as an insect repellent on clothing, and for the maintenance of pet health. Depending on the application type, some portion of the pyrethroid may be disposed of down the drain via cleaning of hard surfaces after application, washing of clothing or bedding after treatment, and bathing pets indoors. As pyrethroids traverse the sewer system and eventually are released from wastewater treatment plants, a large fraction is removed from the effluent water due to the extremely high hydrophobicity of pyrethroids and the prevalence of organic material to which it can adsorb. However, some pyrethroid residues do pass through to the POTW effluent along with dissolved organic matter and these are mixed into river flow. It is at this point (as well as for downstream river reaches), that an assessment of the potential ecological effects of the bioavailable fraction of pyrethroids must be conducted. Using results for several pyrethroids, this presentation will discuss the relevant aspects that should be considered in an ecological risk assessment. In addition, a tiered approach for conducting an exposure assessment using models at various spatial scales will be presented along with an evaluation of the potential impact of various sources of uncertainty in these assessments. Comprehensive pyrethroid POTW monitoring data are available to help provide context for refined model output.

Chris Holmes* , Stephanie Herbstritt, Amy Ritter (Waterborne Environmental), Scott Jackson (BASF Corporation), Russell Jones (Bayer CropScience), Paul Hendley (Phasera Ltd.), Richard Allen (Valent USA Corportation), Gary Mitchell (FMC Corporation). “Ecological Exposure Assessment Approaches for Indoor Use Pyrethroids in POTW Effluent”. Presentation. ACS 2016.

Crop ProtectionPresentations

Predicting Pesticide Biphasic Soil Concentration Decline Under Field Conditions: Model-Data Comparison

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  • Session title: Subsurface Fate of Pesticides
  • Presentation type: Presentation
  • Presentation room: Commonwealth Hall A2 at 9:45AM
  • Presentation date: Thursday, August 25, 2016
  • Presenting Author: Dazhi Mao

As part of the NAFTA degradation kinetics calculation process, the Double First-Order in Parallel (DFOP) model is considered along with the Single First Order (SFO) and the Intermediate Order Rate Equation (IORE). However, only SFO kinetics are represented in pesticide fate regulatory modeling tools like the Pesticide Root Zone Model (PRZM), thus hindering the model’s capability of simulating chemicals with biphasic degradation characteristics. We have recently incorporated DFOP into synPRZM, a PRZM-based environmental fate model as an additional option to the sorption kinetics developed by Syngenta and Waterborne for predicting field soil residue declines. The model codes in synPRZM treat the chemical under simulation as two separate fractions which are determined by the DFOP degradation kinetics, with each fraction having a distinct degradation rate constant. Both fractions are simulated simultaneously each day, and the sum of their results is output as a whole for the chemical. Using DFOP parameters independently measured in laboratory soil metabolism studies, synPRZM was able to predict a number of field soil residue data sets reasonably well without elaborated calibration. Predicted soil pore water concentrations from synPRZM are compared with measured data from field lysimeters. The robust performance of synPRZM demonstrates the model’s predictive capability as a useful and pragmatic option to handle biphasic degradation behavior frequently observed in pesticide field studies.

Dazhi Mao* (Waterborne Environmental), Wenlin Chen (Syngenta Crop Protection), Mark Cheplick (Waterborne Environmental). “Predicting Pesticide Biphasic Soil Concentration Decline Under Field Conditions: Model-Data Comparison”. Presentation. ACS 2016.

Crop ProtectionPresentations

Leveraging Ambient and Focused Monitoring Data to Refine Regulatory Modeling Exposure Estimates

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  • Session title: Increasing the Value of Water Monitoring Data for Pesticide Fate & Effects Evaluations
  • Presentation type: Presentation
  • Presentation room: Commonwealth Hall A1 at 9:20-9:45AM
  • Presenting Author: Nathan Snyder

Re-registration of crop protection products under USEPA or Health Canada’s PMRA regulatory frameworks lead to a revision of exposure estimates based on updating of regulatory tools and guidance for use of environmental fate data. Particularly with revised groundwater tools, risks are being identified that are substantially different than previous assessments or as demonstrated in the monitoring data. For products with a long use history, extensive monitoring data is often available. In this case study, the authors will present a comparison of the extensive monitoring data and new exposure estimates. Learnings from detailed studies like Prospective Groundwater (PGW) Studies along with the use of monitoring data points with demonstrated applicability to labeled use patterns are used to improve the modeling predictions by presenting scenarios and parameterization refinement options. The authors will highlight areas where monitoring can be used to augment the modeling efforts leading to protective, yet more realistic exposure estimates for use in risk assessments.

Nathan Snyder*, Kendall Jones (Waterborne Environmental), Aldos Barefoot (DuPont). “Leveraging Ambient and Focused Monitoring Data to Refine Regulatory Modeling Exposure Estimates”. Presentation. ACS 2016.

Crop ProtectionPresentations

Monitoring Approaches to Provide Temporal and Spatial Context to Residential Pesticide Occurrence in the American River

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  • Session title: Environmental Fate & Modeling of Agriculturally-Related Chemicals
  • Presentation type: Poster
  • Presentation room: Regency Ballroom B on display from 1:00PM – 5:00PM
  • Presentation date: Monday, August 22, 2016
  • Presenting Author: Greg Goodwin

Extensive urban stream and river monitoring for residential use pyrethroids has been conducted in California over the last few years and detectable residues of potential concern have been measured in some samples. Unfortunately, most of these monitoring programs have been based on simple grab sampling and have reported whole water residues; as a result, the temporal and spatial context of biologically relevant pyrethroid residues remains unknown. Consequently, a program was designed to address these questions by employing a spatially robust monitoring design at 8 locations down the length of the lower American River. The design specified multiple replicate sample collection across a variety of time scales (hourly to multi-day) during several dry weather and rainfall driven monitoring events over a 3-year period. Both discrete and depth-integrated water column samples were collected at each location with associated measurements of flow rate, depth and suspended solids concentrations. Both cross-sectional and Lagrangian sampling techniques were utilized, providing spatial characterization both within a river cross-section as well as longitudinally up and down a river reach. Analyses quantified pyrethroid residues and TOC co-occurrence. This rich long-term monitoring dataset, combined with GIS approaches allows a detailed analysis of residential pesticide residue occurrence in space and time and provides context for the program results which show that while higher pyrethroid residues do occasionally occur during storm events they are spatially confined, transient (on a time-scale of a few hours), rapidly diluted and heavily modified by the presence of dissolved and particulate organic matter. This work also allows data from other monitoring programs and publications to be put into context.

Greg Goodwin (Waterborne Environmental), Stephen Clark (Pacific EcoRisk), Gary Mitchell (FMC), Scott Jackson (BASF Corporation), Chris Harbourt (Agrible), Paul Hendley (Phasera Ltd.). “Monitoring Approaches to Provide Temporal and Spatial Context to Residential Pesticide Occurrence in the American River”. Poster. ACS 2016.

Crop ProtectionPresentations

Placing EPA Tier II Scenarios into National Context in Terms of Runoff-Erosion Vulnerability After Pyrethroid Applications to Agriculture

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  • Session title: Environmental Fate, Transport & Modeling of Agriculturally-Related Chemicals
  • Presentation type: Presentation
  • Presentation room: Regency Ballroom C1 at 8:55AM
  • Presentation date: Wednesday, August 24, 2016
  • Presenting Author: Chris Holmes

US EPA regulatory evaluations of pesticides utilize crop-specific scenarios in a tiered exposure assessment framework. EPA defines the standard scenarios as “… best professional judgement sites expected to produce runoff greater than would be expected at 90% of the sites for a given crop/use”. In order to evaluate standard scenario relevance for pyrethroid runoff and erosion, PWG has examined 15 crop scenarios using two different approaches. Firstly, the single field scale where 10-ha of a single soil is 100% cropped to the crop of interest was considered. The 90thpercentile annual maximum runoff/erosion flux of a representative pyrethroid was estimated for each SSURGO soil shown by NASS CDL to have been cropped to each of the 15 crops over a 5-year period. This estimation used standard PRZM modeling with the nearest approved SAMSON 30-yr weather data and regional cropping dates. The second approach considered the real world catchment scale where surface waters receive runoff from multiple fields. The 90th percentile pyrethroid runoff/erosion fluxes were summed for all soil areas in each NHD+ catchment on which a given crop was grown. In both cases, the predicted runoff/erosion pyrethroid loads were ranked to produce distributions against which the runoff/erosion loads from the corresponding standard EPA Tier II scenarios were compared to assess their relative vulnerability. The first approach indicated that across the 15 EPA standard scenarios, predicted runoff/erosion loading vulnerabilities varied with approximately half above and half below the 85th percentile. However, when compared to the summed pyrethroid runoff/erosion fluxes from soils growing each crop in real-world small catchments, 12 of the 15 EPA standard scenarios fell above the 99th percentile for runoff/erosion vulnerability for pyrethroids, and in two cases were more severe than any NHD+ catchment in the US. The approaches, results and implications of these analyses will be presented.

Chris Holmes*, Dean Desmarteau, Joshua Amos, Mark Cheplick, Amy Ritter (Waterborne), Paul Hendley (Phasera.). “Placing EPA Tier II Scenarios into National Context in Terms of Runoff-Erosion Vulnerability After Pyrethroid Applications to Agriculture”. Presentation. ACS 2016.

Crop ProtectionPresentations

Variations on a Theme: Groundwater Sensitivity

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  • Session title: Subsurface Fate of Pesticides
  • Presentation type: Presentation
  • Presentation room: Commonwealth Hall A2 at 8:55AM
  • Presentation date: Thursday, August 25, 2016
  • Presenting Author: Amy Ritter

Downward water movement and subsurface degradation are key factors in estimates of pesticide concentrations in groundwater. Since PRZM-GW estimated drinking water concentrations (EDWC) are averaged over 30 years as opposed to estimating 90th percentile concentrations, timing of heavy (>2 inches) storms have a huge impact on EDWC for compounds with extremely short half-lives as compared to persistent compounds due to moving the pesticide out of the degradation zone. This presentation show the sensitivity of various factors including timing of rain storms, type of application, and soil degradation was evaluated with PRZM-GW (USEPA’s groundwater assessment tool) and PRZM-VADOFT. In addition, various soil degradation schemes were simulated and analyzed for the degradation in soil to the 1-m depth and degradation in soil below 1 m. The EDWC results were reduced 5 fold or to negligible concentrations as compared to results predicted following US EPA PRZM-GW guidance. The impact of these modeling assumptions will be tested with these two models.

Amy Ritter*, Mark Cheplick, Ishadeep Khanijo (Waterborne Environmental). “Variations on a Theme: Groundwater Sensitivity”. Presentation. ACS 2016.

Crop ProtectionPresentations

Three Estuarine Mixing Scenarios for Pesticide Risk Assessment

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Session: Environmental Fate, Transport & Modeling of Agriculturally-Related Chemicals
Time: 1:30PM – 1:55PM
Location: Regency Ballroom C1 – Loews Philadelphia Hotel
Type: Presentation

The US EPA, the National Marine Fisheries Service, the US Fish & Wildlife Service, and pesticide registrants are focused on accurately assessing the potential risks of pesticides to threatened and endangered species. Currently, the EPA’s Office of Pesticide Programs assesses risk with a modeling system, the Pesticide in Water Calculator (PWC), which couples the daily-time-step, field-scale numerical-solution model Pesticide Root Zone Model (PRZM) with the Variable Volume Water Model (VVWM). The VVWM has various receiving water mixing scenarios, including estuarine and coastal zones, but none of the scenarios consider tidally-driven sea water stratification and sediment transport processes. This creates a significant gap in understanding the exposure component of pesticide risk assessment, since the toxicology data component – – pesticide toxicity to marine and estuarine organisms – – is usually complete and available. We propose to create three distinct marine/estuarine mixing scenarios for incorporation into the VVWM: salmonids in the Pacific Northwest, coral in the Hawaiian Islands or the Florida Keys, and crustaceans in the Chesapeake Bay. The diverse scenarios include a coastal embayment or a marine shoreline, a salt wedge estuary, and a drowned eroded river valley. The biology of target species will drive the development of each scenario; e.g., the coral reef embayments will not have high TSS concentrations (coral doesn’t grow in high TSS environments). A key consideration will be the exchange coefficient, i.e., the exchange of conservative substances due to tidal circulation. The full semi-diurnal tide will be considered so that times such as the slack tide period, when many of the organisms are feeding and there is low mixing, will be fully considered. The study will characterize the circulation, geometry, and aquatic chemistry of each habitat. Water, salt, and pesticide mass balances based on box model volume elements will be constructed that represent multiple vertical and horizontal segments. A key phase will be testing the models against field data for each scenario.

Stuart Cohen (Environmental & Turf Services), Louis Thibodeaux (Louisiana State University), Craig Jones (Integral Consulting), Martin Williams (Waterborne Environmental), Sandra Haefner (Environmental & Turf Services). “Three Estuarine Mixing Scenarios for Pesticide Risk Assessment”. ACS Philadelphia Presentation. August 2016.