Waterborne Search Waterborne Navigation

Publications

PresentationsCrop Protection2020

An Overview of Key Features of Population Models and Their Relevance for Ecological Risk Assessment

View MoreView Less

Session Title: 5.06 – Environmental Effects Modeling: Advances in Development and Application of Effects Models in Environmental Risk Assessment
SciCon2 5.06.01

Abstract:

The last two decades have seen substantial advances in the development of population models for the ecological risk assessment (ERA) of chemicals. These include guidance on systematic and consistent model creation and documentation, model evaluation and testing, and choosing models of appropriate complexity to address different types of risk assessment questions. A growing collection of case studies has clearly demonstrated how such models can inform risk assessment and risk management decisions, and slowly but surely there are indications that the acceptance of population models for ERA will continue to increase. Nevertheless, there remain misconceptions about population models for ERA, including confusion regarding differences among types of model formalization (e.g., differential equation, matrix or agent-based models), uncertainty surrounding the implications of including or ignoring different aspects of reality in the models, as well as a lack of consensus on the role that the models should play in the ERA process. We provide an overview of the key features that may be included in population models to inform ERAs. They include density dependence, spatial variability, external drivers, stochasticity, life history, behavior, energetics and how exposure and effects are integrated in the models. We consider why these features are relevant for ERA and how they can be incorporated into three broadly defined population model categories: unstructured, structured, and agent-based. We show that nearly all features can be included in all model categories, but some features are more or less easily incorporated in certain model types. Using a previously published database of population models, we assessed the frequency with which each of the key features has been included so far in the different model categories. We show that some features have been more strongly associated with a certain model category. The aims of the overview are to help model developers and model evaluators assess the extent to which a model and its features are fit for purpose and to increase the consistency and transparency of population models used for ERA.

C. Accolla (University of Minnesota), M. Vaugeois (University of Minnesota), V. Grimm (Helmholtz Centre for Environmental Research – UFZ), A. Schmolke (Waterborne), A. Moore (University of Minnesota), P. Rueda-Cediel  (University of Minnesota), V. Forbes (University of Minnesota)

An Overview of Key Features of Population Models and Their Relevance for Ecological Risk Assessment. SciCon2 5.06.01, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

Assessing the Risks of Pesticides to Terrestrial Threatened and Endangered Species: Opportunities to Refine Risk Assessments for Listed Terrestrial Plants

View MoreView Less

Session Title: 5.04 – Endangered Species Assessments for Pesticides
SciCon2 5.04.14

Abstract:

There is a continuing need to develop improved procedures and tools for assessing pesticide risks to threatened and endangered (i.e., listed) species in the United States. As part of meeting this challenge, the TERrestrial Endangered Species Assessment (TERESA) model was developed following a tiered approach to efficiently evaluate potential pesticide exposures and risks to listed terrestrial species. The terrestrial plant version of TERESA includes the ability to evaluate risks to listed plant species based on direct effects or potential indirect pathways (e.g., effects to insect pollinators or obligate symbionts). For species that are not screened out in the first tiers of the analysis in TERESA, various refinements can be conducted to better characterize risk using information about the species and relevant product use patterns. We conducted refined case studies for a subset of listed terrestrial plant species potentially exposed to a representative insecticide. Multiple lines of evidence were evaluated including refined spatial exposure estimates based on product use information and species life history and characteristics that may influence exposure potential. Factors considered in these analyses include local use conditions, application rates and methods, temporal relationships between species and application timing and species habitat associations. Given the low direct toxicity of this pesticide to terrestrial plants, the focus is on illustrating an approach to evaluate risk to biological features upon which the listed plant species depends. The case studies highlight the importance of bringing together the most reliable and relevant information to reduce uncertainty and improve our understanding of pesticide risk to listed species.

M. Kern (Balance EcoSolutions LLC), N. Green (Waterborne), N. Snyder (Waterborne), D. Moore (Intrinsik), S. Teed (Intrinsik), C. Priest (Intrinsik), H. Rathjens (Stone Environmental), M. Winchell (Stone Environmental), T. Blickley (Eurofins EAG Agroscience Services LLC)

Assessing the Risks of Pesticides to Terrestrial Threatened and Endangered Species: Opportunities to Refine Risk Assessments for Listed Terrestrial Plants. SciCon2 5.04.14, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

A Tiered Approach to Efficient Refinement of Aquatic Exposure Assessments for Endangered Species

View MoreView Less

Session Title: 5.04 – Endangered Species Assessments for Pesticides
SciCon2 5.04.08

Abstract:

Quantitative pesticide exposure and risk modeling is a powerful tool to effectively and efficiently make the important distinction between threatened and endangered species that are likely to be and not likely to be adversely affected (LAA and NLAA, respectively) as a resulted of a pesticideís labeled uses. To achieve efficiency and transparency in such assessment for aquatic species, progressive steps in exposure modeling are needed that employ the best available datasets and scientific approaches to introduce meaningful and substantial refinements. We have developed a multi-tiered approach for aquatic exposure modeling designed to meet these requirements for national scale endangered species risk assessments. The approach begins with Tier 1 which is highly conservative and represents potential high-end exposure for all species. Tier 1 accounts for a wide range of potential use patterns, cropping scenarios, application dates, and weather conditions. At Tier 2, much greater relevance of the exposure estimates for each species is achieved by accounting for the spatial overlap between pesticide exposure scenarios and species ranges and critical habitats. In Tier 2, two additional refinement steps are incorporated into the exposure modeling. The first refinement accounts for potential pesticide use sites, or percent cropped area (PCA), in estimating exposure concentrations in multiple static and flowing aquatic habitat types. PCA for large numbers of relevant water bodies within a species range are analyzed using GIS datasets and processing techniques. The second refinement step in Tier 2 is based on best available pesticide usage data. Usage data are analyzed probabilistically to generate an ensemble of pesticide usage scenarios across the US and overlaid with species ranges. This pesticide usage data refinement step results in quantitative pesticide exposure probability distributions that are then incorporated into risk assessment decisions. The two-tier methodology developed is an efficient, effective, and transparent process using best available data and scientific analysis methods that helps guide a risk assessor to making NLAA/LAA decisions in national endangered species risk assessments.

M. Winchell (Stone Environmental), H. Rathjens (Stone Environmental), S. Castro-Tanzi (Stone Environmental), J. Dunne (Stone Environmental), N. Snyder (Waterborne), P. Havens (Corteva Agriscience)

A Tiered Approach to Efficient Refinement of Aquatic Exposure Assessments for Endangered Species. SciCon2 5.04.08, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

Assessing the Risk of Pesticides to Threatened and Endangered Species: Developments of Process and Tools

View MoreView Less

Session Title: 5.04 – Endangered Species Assessments for Pesticides
SciCon2 5.04.02

Abstract:

In the United States, registration of a pesticide is considered a Federal action and, as such, requires a review of potential impacts to threatened and endangered species (listed species) and their designated critical habitats under the Endangered Species Act (ESA). There are over 1600 listed species in the United States, multiple use sites for each pesticide active ingredient, and three agencies (the US Environmental Protection Agency (EPA), Fish and Wildlife Service (FWS), and National Marine Fisheries Service (NMFS), collectively ìthe Agenciesî) involved in each assessment. Thus, an endangered species risk assessment (ESRA) for a pesticide is an enormous undertaking. Although there has been progress towards developing more efficient and scientifically defensible approaches for pesticide ESRAs, continuous improvement in these methods is required. This presentation describes investigations into the development of ever more efficient, transparent, reproducible, and sustainable ESRA processes for pesticides, including the development of innovative and user-friendly new tools. We illustrate these developments with case studies involving representative insecticide, herbicide and fungicide chemistries. Subsequent presentations in this session will describe many of the tools and approaches that were developed as part of this work.

D. Moore (Intrinsik), T. M. Blickley (Corteva Agriscience), L. Brewer (Compliance Services International), A. Frank (Compliance Services International), J. Giddings (Compliance Services International), P. Havens (Corteva Agriscience), M. Kern (Balance EcoSolutions LLC), C. Priest (Intrinsik), B. McGaughey (Compliance Services International), H. Rathjens (Stone Environmental), N. Snyder (Waterborne), R.S. Teed (Intrinsik), M. Whinchell (Stone Environmental)

Assessing the Risk of Pesticides to Threatened and Endangered Species: Developments of Process and Tools. SciCon2 5.04.02, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

Coupling PRZM with SWAT for Ecological Risk Assessment of Agricultural Pesticides

View MoreView Less

Session Title: 4.03 – Exposure: Processes and Approaches for Estimating Environmental Exposures
SciCon2 4.03.10

Abstract:

Ecological risk assessment for the regulatory compliance of agricultural pesticides requires determination of potential exposure levels in receiving water bodies to which aquatic organisms may be exposed. Modeling and monitoring approaches are key methods used in determining pesticide exposure levels, length and frequency of occurrences. In this study, we present a modeling framework involving a conjunctive use of the field-scale PRZM and watershed-scale SWAT environmental models. The use of PRZM-SWAT modeling framework allowed to leverage PRZM is detailed field-level representation of pesticide fate and transport processes and SWAT is key hydrological and biogeochemical attenuation processes between edge of field losses and loss in water moving from the field into surface water networks. The PRZM-SWAT modeling framework was calibrated using a Monte Carlo approach to stream flow and a 4-, 7-, 21-, 30-, and 60-day maximum annual rolling average exposure durations, that are of significance to the ecological risk assessments. The performance of the model was evaluated using 8-year monitoring of atrazine data and stream flow from a high use-intensity, headwater watershed in Missouri. This presentation will describe the modeling framework, calibration approaches, and results of the modeling performances.

L. Ghebremichael (Syngenta), W. Chen (Syngenta), A. Jacobson (Waterborne), C. Roy (Waterborne)

Coupling PRZM With SWAT for Ecological Risk Assessment of Agricultural Pesticides. SciCon2 4.03.10, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

A Dfop-Based PRZM Model to Predict Non-First Order Degradation and Subsurface Transport in Soil and Groundwater

View MoreView Less

Session Title: 4.03 – Exposure: Processes and Approaches for Estimating Environmental Exposures
SciCon2 4.03.02

Abstract:

Many soil metabolism and other environmental fate studies have observed non-first order degradation often in a biphasic pattern with fast initial decline followed by a noticeably slower phase. The decline pattern deviates from the classical simple first-order (SFO) kinetics. Although widely recognized, biphasic degradation has never been directly incorporated into regulatory models. Instead, regulatory modeling policies require an SFO curve fit preferentially to the slow portion of the decline data while largely ignoring the fast initial phase. As a result, modeling errors in the predicted exposure levels in surface and ground waters can be artificially elevated. This paper examines the impact of biphasic degradation on pesticide leaching behavior using a PRZM-based model synPRZM developed by Syngenta and Waterborne. The model directly incorporates the kinetics of Double First-Order in Parallel (DFOP) to account for the complete biphasic decline profile. Sensitivity analysis of synPRZM shows that the model converges to the same results of the original PRZM model when the kinetics fit is SFO. When the kinetics shows DFOP characteristics, synPRZM can represent biphasic degradation better. Using DFOP, synPRZM was able to predict several field soil residue data sets reasonably well without elaborated model calibration. Predicted soil pore water concentrations from synPRZM are also compared with measured data from field lysimeters. The overall model performance suggests synPRZM can be used as a predictive tool to handle biphasic degradation behavior frequently observed in pesticide field studies. The inherent nature of DFOP reflecting the rate-limiting effect of time-dependent sorption on biodegradation is also examined for the soil-pore water system.

W. Chen (Syngenta), M. Cheplick (Waterborne), D. Mao (Waterborne)

A Dfop-Based PRZM Model to Predict Non-First Order Degradation and Subsurface Transport in Soil and Groundwater. SciCon2 4.03.02, SETAC 2020 Virtual Meeting.

PresentationsWater/Wastewater Assessments2020

Expansion of the iSTREEM Environmental Exposure Model to Canada and Mexico

View MoreView Less

Session Title: 4.13 – Late Breaking: Chemistry and Exposure Assessment
SciCon2 4.13.23

Abstract:

The iSTREEMÆ model (www.istreem.org), a broad scale spatially explicit aquatic exposure model covering the continental U.S., is a robust tool for estimating exposure from the use of down the drain chemicals. Leveraging the iSTREEM model is fundamental principles and river routing algorithm, and through the strategic integration of best available global data and modeling tools, a spatially explicit global environmental exposure modeling framework was developed. Global mean annual river flow was generated based on the Curve Number approach and combined with global hydrology network of catchments and rivers from HydroBASINS and HydroRIVERS. Detailed population and best available country specific water use and wastewater treatment plant (WWTP) information were integrated with the modeling framework to provide a means to estimate a distribution of environmental concentrations of chemicals disposed down the drain. In this presentation, use of the global framework to develop models for Canada and Mexico is discussed. WWTP locations, population connected to WWTPs, per capita water use, and direct discharge information were collected from national sources. The WWTP locations were spatially integrated with the river hydrology network and the corresponding river flows at a catchment level. The model estimates catchment specific wastewater effluent concentrations, dilution factors, and river concentrations and routes flow and chemicals across the river network. Modeling results from a case study chemical will be discussed against monitoring data from literature to compare modeled concentrations with measured data. The spatial and probabilistic nature of the model provides a robust means to estimate exposure over a large geography. The presentation demonstrates the expansion of iSTREEM and the global model framework to conduct down the drain environmental exposure assessments for Canada and Mexico.

R. Vamshi (Waterborne), B. Kent (Waterborne), K. McDonough (Proctor & Gamble), M. Fan (Proctor & Gamble), S. Csiszar (Proctor & Gamble), T. Bradley (American Cleaning Institute), K. Stanton (American Cleaning Institute)

Expansion of the iStreem Environmental Exposure Model to Canada and Mexico. SciCon2 4.13.23, SETAC 2020 Virtual Meeting.

PresentationsCrop Protection2020

Towards an efficient and improved approach for assessing risks of pesticides to endangered species in the United States: Methomyl case study

View MoreView Less

ACS 2020, AGRO 178
Session Title: Integrating Species Conservation with Pesticides from Bench to Market
Available Monday, August 17, 2020 at 8:00am

Abstract:

Under the Endangered Species Act, the US Environmental Protection Agency (EPA) and the Services (National Marine Fisheries Service and Fish & Wildlife Service) are required to assess potential risks to threatened and endangered (listed) species as part of the process to register pesticides. EPA issued interim guidance for developing biological evaluations (BE) for pesticides in 2015. Since then, the EPA, the Services, the regulated community and others have continued to develop and refine national endangered species risk assessment (ESRA) methodologies, first with 3 organophosphates and recently with two carbamates, carbaryl and methomyl. In March 2020, EPA issued revised guidance for conducting BEs. Much, however, remains to be done to develop the most efficient, practical and scientifically defensible approach. Therefore, we are developing an improved scientific approach with methods that more efficiently screen out listed species that are not at risk earlier in the tiered assessment process. The approach begins with simple methods such as off-ramping (e.g., screening out listed species that have no potential for exposure); conservative, protective screening-level risk assessments to screen out entire receptor groups that are tolerant of exposure; and co-occurrence analyses to screen out species not present in pesticide use areas. We are developing spatially explicit, species-specific tools for each major receptor group to determine which listed species are potentially at risk using more advanced, but still protective, methods. Using methomyl as a case study, we demonstrate how these early tier methods can efficiently reduce the formidable scope of a national ESRA to focus on those listed species most at risk. The latter species would then proceed to probabilistic, more refined modeling and proper weight-of-evidence assessments.

D. Moore (Intrinsik), S. Teed (Intrinsik), C. Priest (Stone), M. Winchell (Stone), H. Rathjens (Stone), A. Frank (CSI), J. Giddings (CSI), M. Kern (Balance EcoSolutions), N. J. Snyder (Waterborne), T.M. Blickley (Corteva Agriscience), P.L. Havens (Dow AgroSciences).
Towards an efficient and improved approach for assessing risks of pesticides to endangered species in the United States: Methomyl case study. AGRO 178, ACS 2020. Virtual Meeting.

PostersWater/Wastewater Assessments2020

Geospatial model to estimate microplastics entering waterways from wastewater systems and land applied biosolids

View MoreView Less

ACS 2020, AGRO 150
Session Title: Environmental Fate of Agrochemicals

Abstract:

There is a need for exposure models to simulate the pathways and transport of such particles in waterways especially with increasing public awareness about the presence of microplastics in the environment. Microplastics may enter the environment from various sources and in many forms. One source includes personal care products containing plastic particles being washed down residential drains and entering municipal wastewater treatment plants (WWTPs). A large portion of these plastic particles are removed from the water phase during the treatment process, and generally end up in the solids (i.e., sludge). Sludge disposal varies by country, region and locality, including landfill, incinerator, compost, or as land-applied biosolids. There is potential for particles in biosolid applications to reach aquatic systems depending on application location and subsequent environmental conditions. This poster will present a broad-scale model designed to estimate emissions and model the fate of plastic particles exiting WWTPs into the terrestrial and aquatic environments in Europe. The model uses geospatial information on WWTPs, river hydrology and terrestrial transport potential. This regional/continental scale model is based on publicly available datasets and contained in a modular and transparent framework which is scalable and portable to multiple geographies. This presentation will demonstrate the utility of the model and how the resulting information about ultimate mass disposition (e.g., soil, freshwater, sediment, marine) and concentrations (surface water, sediment) can be used to help inform the discussion about prospectively assessing the presence and concentration of microplastics in the environment as emitted by WWTPs as effluent or transport from fields applied with biosolids.

A. Ritter, C. Roy, C. Hoogeweg (Waterborne), C. Holmes (Applied Analysis Solutions, LLC). Geospatial model to estimate microplastics entering waterways from wastewater systems and land applied biosolids. AGRO 150, ACS 2020. Virtual Meeting.

Presentations2020

Reflections on our AGRO division: Fifty years of engagement

View MoreView Less

ACS 2020, AGRO 72
Session Title: Chemistry for Sustainable Agriculture and Public Health: AGRO Evolution and Future Opportunities
Monday, August 17, 2020 8:00AM

Abstract:

This talk will cover AGRO Division’s fifty year relationship with the broader aspects of agrochemical history. We will embark on a historical look back at AGRO’s role as a crucible for discussions of emerging issues in the protection of agricultural productivity, public health and the environment with engagement across industry, academia, and key government agencies. We will highlight key aspects of our division’s governance that have positioned us for meaningful AGRO awards, international participation, student engagement and career development opportunities for all.

As part of the celebration plans, a 50th Timeline Team formed to capture submitted milestones from across our AGRO membership; the results of those efforts inform this talk.

C. Barnett Cleveland (BASF), A.Ritter (Waterborne), T.A. Wehner. Reflections on our AGRO division: Fifty years of engagement. AGRO 72, ACS 2020. Virtual Meeting.