Papers & ReportsHome and Personal Care Products, Water/Wastewater Assessments2015
Mixing Zone and Drinking Water Intake Dilution Factor and Wastewater Generation Distributions to Enable Probabilistic Assessment of Down-The-Drain Consumer Product Chemicals in the U.S.
Environmental exposure and associated ecological risk related to down-the-drain chemicals discharged by municipal wastewater treatment plants (WWTPs) are strongly influenced by in-stream dilution of receiving waters which varies by geography, flow conditions and upstream wastewater inputs. The iSTREEM® model (American Cleaning Institute, Washington D.C.) was utilized to determine probabilistic distributions for no decay and decay-based dilution factors in mean annual and low (7Q10) flow conditions. The dilution factors derived in this study are “combined” dilution factors which account for both hydrologic dilution and cumulative upstream effluent contributions that will differ depending on the rate of in-stream decay due to biodegradation, volatilization, sorption, etc. for the chemical being evaluated. The median dilution factors estimated in this study (based on various in-stream decay rates from zero decay to a 1 h half-life) for WWTP mixing zones dominated by domestic wastewater flow ranged from 132 to 609 at mean flow and 5 to 25 at low flow, while median dilution factors at drinking water intakes (mean flow) ranged from 146 to 2 × 107 depending on the in-stream decay rate. WWTPs within the iSTREEM® model were used to generate a distribution of per capita wastewater generated in the U.S. The dilution factor and per capita wastewater generation distributions developed by this work can be used to conduct probabilistic exposure assessments for down-the-drain chemicals in influent wastewater, wastewater treatment plant mixing zones and at drinking water intakes in the conterminous U.S. In addition, evaluation of types and abundance of U.S. wastewater treatment processes provided insight into treatment trends and the flow volume treated by each type of process. Moreover, removal efficiencies of chemicals can differ by treatment type. Hence, the availability of distributions for per capita wastewater production, treatment type, and dilution factors at a national level provides a series of practical and powerful tools for building probabilistic exposure models.
Katherine E. Kapo, Kathleen McDonough, Thomas Federle, Scott Dyer, Raghu Vamshi, 15 June 2015. “Mixing Zone and Drinking Water Intake Dilution Factor and Wastewater Generation Distributions to Enable Probabilistic Assessment of Down-The-Drain Consumer Product Chemicals in the U.S.”. Science of the Total Environment, Volumes 518–519, pp. 302-309. DOI: 10.1016/j.scitotenv.2015.02.105
Papers & ReportsWater/Wastewater Assessments2014
Hydraulic “Fracking”: Are Surface Water Impacts an Ecological Concern?
Use of high-volume hydraulic fracturing (HVHF) in unconventional reservoirs to recover previously inaccessible oil and natural gas is rapidly expanding in North America and elsewhere. Although hydraulic fracturing has been practiced for decades, the advent of more technologically advanced horizontal drilling coupled with improved slickwater chemical formulations has allowed extensive natural gas and oil deposits to be recovered from shale formations. Millions of liters of local groundwaters are utilized to generate extensive fracture networks within these low-permeability reservoirs, allowing extraction of the trapped hydrocarbons. Although the technology is relatively standardized, the geographies and related policies and regulations guiding these operations vary markedly. Some ecosystems are more at risk from these operations than others because of either their sensitivities or the manner in which the HVHF operations are conducted. Generally, the closer geographical proximity of the susceptible ecosystem to a drilling site or a location of related industrial processes, the higher the risk of that ecosystem being impacted by the operation. The associated construction of roads, power grids, pipelines, well pads, and water-extraction systems along with increased truck traffic are common to virtually all HVHF operations. These operations may result in increased erosion and sedimentation, increased risk to aquatic ecosystems from chemical spills or runoff, habitat fragmentation, loss of stream riparian zones, altered biogeochemical cycling, and reduction of available surface and hyporheic water volumes because of withdrawal-induced lowering of local groundwater levels. The potential risks to surface waters from HVHF operations are similar in many ways to those resulting from agriculture, silviculture, mining, and urban development. Indeed, groundwater extraction associated with agriculture is perhaps a larger concern in the long term in some regions. Understanding the ecological impacts of these anthropogenic activities provides useful information for evaluations of potential HVHF hazards. Geographic information system–based modeling combined with strategic site monitoring has provided insights into the relative importance of these and other ecoregion and land-use factors in discerning potential HVHF impacts. Recent findings suggest that proper siting and operational controls along with strategic monitoring can reduce the potential for risks to aquatic ecosystems. Nevertheless, inadequate data exist to predict ecological risk at this time. The authors suggest considering the plausibility of surface water hazards associated with the various HVHF operations in terms of the ecological context and in the context of relevant anthropogenic activities. Environ Toxicol Chem 2014;33:1679–1689. © 2014 SETAC
Burton, G. A., Basu, N., Ellis, B. R., Kapo, K. E., Entrekin, S. and Nadelhoffer, K. (2014), Hydraulic “Fracking”: Are surface water impacts an ecological concern?. Environmental Toxicology and Chemistry, 33: 1679–1689. doi: 10.1002/etc.2619
PostersCrop Protection, Water/Wastewater Assessments2014
Implementing National-Scale Proximity Analyses with Efficiency & Reliability
Performing a National Threatened and Endangered Species Risk assessment for each pesticide registration action is daunting. The scale, both geographically, temporally, and the sheer number of species, presents a challenge. Add to this the fact that data sets and approaches will be refined moving forward, but current registration efforts cannot be delayed. To effectively perform Proximity Analyses at Step 1, a process which is computationally efficient, technically accurate for the scale, and robust enough to handle changing data sets must be developed. This poster demonstrates an approach to address these challenges. Using authoritative geospatial data from government sources, a National Potential Pesticide Use Site Layer is generated which can be easily updated as new data are released annually. The potential pesticide use site layer is used in a framework that allows for Flexible Action Area Definition and subsequent National Proximity Analysis of 100’s of Species at a Time. Furthermore, Downstream Transport must be accounted for when calculating proximity to Aquatic Species. By using existing Automation and Scripting methods within ArcGIS and SQL Server, the framework can be reapplied as needed (such as availability of newer data), and also provides a source of documentation at each step of the process. This poster illustrates an approach to Implementing National-Scale Proximity Analyses with Efficiency & Reliability and Results.
Joshua J. Amos, Vivienne L. Sclater, and Christopher M. Holmes. Implementing National-Scale Proximity Analyses with Efficiency & Reliability. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
Tiered Testing Approach for Whole-Sediment Toxicity Tests
A majority of recent data call-ins (DCIs) issued by the USEPA for pesticide registrants have included requirements for chronic sediment toxicity testing with midge as well as freshwater and marine amphipod species. Sediment toxicity testing triggers for either acute or chronic studies are currently based predominately on environmental fate data focused on compound-specific degradation and partitioning behavior. Biological data are only used to evaluate risk while determining if chronic sediment data are needed; however, acute sediment toxicity data are seldom available for such comparisons. While ecotoxicity data from water-only studies may be leveraged to estimate thresholds for benthic organisms based on sediment equilibrium partitioning theory; this approach may introduce substantial uncertainty into ecological risk assessment and is likely most effectively used as a lower level screening tool.
Jennifer K. Collins, Mark A. Cafarella. Tiered Testing Approach for Whole-Sediment Toxicity Tests. SETAC North America 35th Annual Meeting, Vancover, B.C. November 14, 2014.
PostersCrop Protection, Water/Wastewater Assessments2014
iSTREEM® – A Web-based River Chemical Concentration Estimation Model for Consumer Pesticide Product Chemicals
In recent years, attention to anthropogenic chemicals in the environment has expanded beyond conventional industrial chemicals and agricultural pesticides to include those used in everyday consumer products such as pharmaceuticals, cosmetics, cleaning products and consumer pesticide product chemicals. Although there is more interest, researchers are often not familiar with use patterns of consumer product ingredients and therefore have more difficulty estimating exposures and impacts to aquatic environments. The American Cleaning Institute developed iSTREEM®, a publicly-available, web-based computer model that predicts the concentration in the environment of chemicals used in products typically disposed of ‘down-the-drain’. iSTREEM®estimates concentration in the effluent of more than 10,000 wastewater treatment plants throughout the continental United States, their resultant mixing zones and downstream river reaches (more than 25,000) and at 1,700 drinking water intakes downstream of wastewater discharges (http://www.cleaninginstitute.org/science/istreem.aspx). The data are geo-referenced permitting combination with similar data sets to reveal spatial relationships. By estimating freshwater exposures, the model permits scientists to understand where the greatest potential chemical risks may lie and how to best develop environmental monitoring programs. Likewise, it is a tool that can be utilized in setting public policy regarding freshwater discharges and pollution prevention. The presentations will feature an application of the model for N,N-Diethyl-m-toluamide (DEET), which is reaching the environment mainly from consumer use of DEET-containing insect repellent. Results will be compared to aquatic toxicity benchmarks to provide a screening-level estimation of risk that may be suitable for regulatory purposes.
iSTREEM® – A Web-based River Chemical Concentration Estimation Model for Consumer Pesticide Product Chemicals. Christopher M Holmes, Paul C DeLeo, John A Weeks, Katherine E Kapo. Poster presentation by Christopher Holmes. ACS/IUPAC 2014.
Papers & ReportsWater/Wastewater Assessments2014
Developing a Foundation for Eco-Epidemiological Assessment of Aquatic Ecological Status Over Large Geographic Regions Utilizing Existing Data Resources and Models
Eco-epidemiological studies utilizing existing monitoring program data provide a cost-effective means to bridge the gap between the ecological status and chemical status of watersheds and to develop hypotheses of stressor attribution that can influence the design of higher-tier assessments and subsequent management. The present study describes the process of combining existing data and models to develop a robust starting point for eco-epidemiological analyses of watersheds over large geographic scales. Data resources from multiple federal and local agencies representing a range of biological, chemical, physical, toxicological, and other landscape factors across the state of Ohio, USA (2000–2007), were integrated with the National Hydrography Dataset Plus hydrologic model (US Environmental Protection Agency and US Geological Survey). A variety of variable reduction, selection, and optimization strategies were applied to develop eco-epidemiological data sets for fish and macroinvertebrate communities. The relative importance of landscape variables was compared across spatial scales (local catchment, watershed, near-stream) using conditional inference forests to determine the scales most relevant to variation in biological community condition. Conditional inference forest analysis applied to a holistic set of environmental variables yielded stressor–response hypotheses at the statewide and eco-regional levels. The analysis confirmed the dominant influence of state-level stressors such as physical habitat condition, while highlighting differences in predictive strength of other stressors based on ecoregional and land-use characteristics. This exercise lays the groundwork for subsequent work designed to move closer to causal inference. Environ Toxicol Chem 2014;33:1665–1677. © 2014 SETAC
Kapo, K. E., Holmes, C.M., Dyer, S. D., de Zwart, D. and Posthuma, L. (2014), Developing a foundation for eco-epidemiological assessment of aquatic ecological status over large geographic regions utilizing existing data resources and models. Environmental Toxicology and Chemistry, 33: 1665–1677. doi: 10.1002/etc.2557.
Papers & ReportsAgriculture and Food, Crop Protection, Water/Wastewater Assessments2014
Sensitivity Analysis of Individual Parameters for Synthetic Pyrethroid Exposure Assessments to Runoff, Erosion, and Drift Entry Routes for the PRZM and AGRO-2014 Models
This analysis focused on individual parameter sensitivity to identify pyrethroid variables that have the greatest impact on predicted runoff and erosion mass loadings from the PRZM model as well those expected to have a significant effect on the receiving water body concentrations predicted by the AGRO-2014 modeling system. This study showed the PRZM and AGRO-2014 models were highly sensitive to numerous individual parameters related to the amount of chemical applied to the field and drift onto the receiving water body, chemical field degradation parameters, factors that greatly influence the content of the edge-of-field runoff/erosion flows, and parameters related to pond geometry and water-sediment partitioning parameters. View chapter >
“Describing the Behavior and Effects of Pesticides in Urban and Agricultural Setting, Chapter 12: Sensitivity Analysis of Individual Parameters for Synthetic Pyrethroid Exposure Assessments to Runoff, Erosion, and Drift Entry Routes for the PRZM and AGRO-2014 Models.” (Desmarteau, D.A. and Ritter, A.M.) American Chemical Society, 2014. Electronic Publication.
Papers & ReportsAgriculture and Food, Crop Protection, Water/Wastewater Assessments2014
Influence of Landcover, Rainfall, and River Flow on the Concentration of Pyrethroids in the Lower American River, Sacramento, California, United States
A multi-site, spatio-temporal transect study on the Lower American River was conducted to systematically investigate the influence of agricultural and urban landcover, river flows and rainfall events on the concentration of pyrethroids. The majority of the flow in this section of the river throughout the year is controlled discharge from Folsom Dam. Local storm drains, small ephemeral channels and an extensive network of organized storm drain collection and pump stations discharge excess rainfall from surrounding urban and suburban environments into the Lower American River channel. Rainfall event-driven sampling was carried out during the 2011-2012 and 2012-2013 rainy seasons for eight pyrethroids. Results indicate that rainfall-runoff events are the driving perturbations behind the infrequent and highly variable pyrethroid movement into the Lower American River. A variety of factors contribute to environmental complexity. However, rainfall is the only true driver, while other land cover complexities, stormwater detention systems, and hard surfaces contribute to the variability in local rainfall-runoff contribution to river flows.
“Describing the Behavior and Effects of Pesticides in Urban and Agricultural Setting, Chapter 7: Influence of Landcover, Rainfall, and River Flow on the Concentration of Pyrethroids in the Lower American River, Sacramento, California, United States.” (Harbourt, C.M., Goodwin, G.E., Clark, S.L., Gantner, D., Sliz, B.A., Albertson, T., Dobbs, M., Henry, K. and Mitchell, G.) American Chemical Society, 2014. Electronic Publication.
Prioritizing Research Needs for Threatened and Endangered Species in California Watersheds
A decline in pelagic species in the San Francisco Bay Delta region has led to speculation as to whether contaminants may be playing a role. A weight-of-evidence analysis was conducted to rank the relative risk potential for pesticides to impact threatened or endangered species in the Sacramento River, San Joaquin River, and Bay-Delta estuary watersheds. The study utilized monitoring data, simulation modeling, and GIS to address the co-occurrence of 40 widely used herbicides, fungicides, and insecticides to 12 aquatic and semi-aquatic species, including Chinook Salmon (Oncorhynchus tshawytscha), Central Valley steelhead (O. mykiss), southern North American Green Sturgeon (Acipenser medirostris), Delta smelt (Hypomesus transpacificus), Striped Bass (Morone saxatilis), San Francisco Longfin Smelt (Spirinchus thaleichthys), Threadfin Shad (Dorosoma petenense), California Red-legged Frog (Rana draytonii), and the California Freshwater Shrimp (Syncaris pacifica). Pesticide application sites represented in model simulations included fruit, vegetable, grain, nuts, rice, landscape maintenance, and structural applications. Daily pesticide concentrations were predicted at the PLSS section level from runoff, erosion, and drift sources. An co-occurrence matrix approach was developed to evaluate the spatial and temporal co-occurrence of pesticides and species. Areas of highest potential concern were located along the main branch of the Sacramento River, the northern part of the Delta region, and the southern part of the Delta in San Joaquin County. A few small clusters of high co-occurrence values were predicted along the Sacramento River Deep Water Ship Channel and in southern Butte County along the Feather River. Monitoring is sparse in a number of these and lesser areas of potential concern. The results of this study can be used to support current and future monitoring programs by strategic placement of sampling locations and frequency. Ultimately, it is hoped that this project will improve decision making and optimize resource spending of groups seeking to improve the long-term sustainability of these aquatic habitats.
Using Spatial and Remote Sensing Technologies to Help Interpret Results from Monitoring Studies and Support Stewardship Initiatives
In the October 2003 Atrazine Interim Reregistration Eligibility Decision (IRED), the US EPA required a statistically designed multiple season intensive monitoring program to measure atrazine concentrations in small headwater streams flowing through highly vulnerable watersheds. 40 watersheds (9-100 sq. mi.) were instrumented and monitored for at least two seasons between 2004 and 2006. Atrazine concentrations were measured at least every 4 days at all sites along with flow and weather data. Detailed GIS data were accumulated and analyzed in order to identify potential drivers of runoff in each watershed. Of these 40 potentially highly vulnerable watersheds, only 3 were determined by EPA to require continued monitoring and a watershed management program based upon the monitoring results. Two of these three streams exhibit intermittent flow during the summer. Monitoring continued after 2007 in these three as well as several adjacent watersheds using a daily auto-sampling protocol.
Hendley P., R. Joseph, C.Harbourt and P. Miller. Using Spatial and Remote Sensing Technologies to Help Interpret Results from Monitoring Studies and Support Stewardship Initiatives. Land Grant and Sea Grant National Water Conference, Washington, DC. Jan. 31-Feb. 1, 2011.