Katherine E. Kapo

Characterizing sediment acid volatile sulfide concentrations in European streams

Sediment acid volatile sulfide (AVS) concentrations were measured in wadeable streams of a wide variety of ecoregions of western Europe (84 sites in 10 countries and nine ecoregions) to better understand spatial distribution and ecoregion relationships. Acid volatile sulfide has been shown to be a major factor controlling the bioavailability and toxicity of many common trace metals, such as Cd, Cu, Ni, Pb, and Zn. Sediment characteristics varied widely. The ratio of the sum of the simultaneously extracted metals (SEM) to AVS ranged from 0.03 to 486.59. The sigmaSEM-AVS ranged from -40.02 to 17.71 micromol/g. On a regional scale, sediment characteristics such as dominant parent soil material showed significant trends in AVS distribution and variation by ecoregion. Total Fe and Mn were correlated weakly with SEM concentrations. Three AVS model approaches (i.e., the SEM:AVS ratio, SEM-AVS difference, and carbon normalization) were compared at threshold exceedance levels of SEM/AVS > 9, SEM-AVS > 2, and SEM-AVS/foc > 150 micromol/g organic carbon (OC). Only 4.76% of the sediments exceeded all three AVS thresholds; 22.6% of the sediments exceeded two models; and 13% of the sediments exceeded one model only. Using the SEM:AVS, SEM-AVS, and fraction of organic carbon models, and including site-specific data and regional soil characteristics, ecoregions 1 (Portugal), 3 (Italy), 4 (Switzerland), and 9 (Belgium/Germany) had the highest potential metals toxicity; ecoregions 13 and 8 (Belgium/France) showed the lowest potential toxicity. However, because AVS can vary widely spatially and temporally, these data should not be considered as representative of the sampled ecoregions. The general relationship between AVS levels and sediment characteristics provides some predictive capability for wadeable streams in the European ecoregions.

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.

Making ecosystem reality checks the status quo

Holistic approaches to assessing stressors and managing aquatic ecosystems should be the rule; instead, they are the exception. Disjointed, overlapping, and competing environmental regulatory actions—all with the noble mission of protecting and restoring the environment—can no longer be justified. For at least 60 years, environmental regulatory programs in the United States, Europe, and other developed countries have relied heavily on various forms of assessing chemical risk to manage and protect ecosystems. Water quality, primarily focused on chemical regulation, emerged from the need to control water pollution problems caused by poor or nonexistent wastewater treatment. The result has been largely a singlechemical approach to environmental management and regulatory programs. To protect aquatic life uses for example, many countries developed water quality criteria for selected priority compounds. Legally enforcing these criteria (such as the Clean Water Act in the U.S.) has undoubtedly reduced chemical pollution, and many aquatic systems have benefited. Abundant information demonstrates, however, that singlechemical standards are just one approach to assess, manage, and regulate aquatic systems. For example, toxicity testing (e.g., the U.S. Environmental Protection Agency’s [U.S. EPA] whole effluent toxicity program [WET]) has been used successfully to help assess effects of chemical interactions and the effects of unknown chemicals that may be present. Such testing, however, addresses only direct toxicity effects. Many aquatic systems are impaired by non-chemical stressors, including invasive species, habitat degradation from agriculture and urbanization, and flowmodifications or are influenced by complex interactions among chemicals and other stressors (e.g., nutrients) that are not addressed using either a singlechemical approach or mixture toxicity testing.

Eco-epidemiology of aquatic ecosystems: Separating chemicals from multiple stressors

A non-toxic environment and a good ecological status are policy goals guiding research and management of chemicals and surface water systems in Europe and elsewhere. Research and policies on chemicals and water are however still disparate and unable to evaluate the relative ecological impacts of chemical mixtures and other stressors. This paper defines and explores the use of eco-epidemiological analysis of surveillance monitoring data sets via a proxy to quantify mixture impacts on ecosystems. Case studies show examples of different, progressive steps that are possible. Case study data were obtained for various regions in Europe and the United States. Data types relate to potential stressors at various scales, concerning landscape, land-use, in-stream physico-chemical and pollutant data, and data on fish and invertebrates. The proxy-values for mixture impacts were quantified as predicted (multi-substance) Potentially Affected Fractions of species (msPAF), using Species Sensitivity Distribution (SSD) models in conjunction with bioavailability and mixture models. The case studies summarize the monitoring data sets and the subsequent diagnostic bioassessments. Variation in mixture toxic pressures amongst sites appeared to covary with abundance changes in large (50-86%) percentages of taxa for the various study regions. This shows that an increased mixture toxic pressure (msPAF) relates to increased ecological impacts. Subsequent multi-stressor evaluations resulted in statistically significant, site-specific diagnosis of the magnitudes of ecological impacts and the relative contributions of different stress factors to those impacts. This included both mixtures and individual chemicals. These results allow for ranking stressors, sites and impacted species groups. That is relevant information for water management. The case studies are discussed in relation to policy and management strategies that support reaching a non-toxic environment and good ecological status. Reaching these goals requires not only focused sectoral policies, such as on chemical- or water management, but also an overarching and solution-focused view.

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.

Estimation of U.S. sewer residence time distributions for national-scale risk assessment of down-the-drain chemicals

Sewer residence time (the amount of time a given volume of wastewater resides in a sewer system prior to treatment) can have a significant influence on predictions of environmental fate and transport of wastewater constituents and corresponding risk assessment. In this study, a geographic information systems-based approach for estimating the distribution of sewer residence times for the U.S. was developed using road networks as a spatial proxy for sewer networks. The suitability of the approach was evaluated using case study municipalities, and the approach was subsequently extrapolated to 3422 wastewater treatment facilities of varying size across the U.S. to estimate a national distribution of sewer residence times. The estimated national median residence time for the U.S. was 3.3h. Facilities serving smaller municipalities (<1 million gallons per day) had comparatively shorter sewer residence times to facilities serving larger municipalities, though the latter comprise a greater proportion of overall national wastewater volume. The results of this study provide an important data resource in combination with chemical in-sewer biodegradation data to enable probabilistic risk assessment of consumer product chemicals disposed of down the drain.

Developing population models: A systematic approach for pesticide risk assessment using herbaceous plants as an example

Population models are used as tools in species management and conservation and are increasingly recognized as important tools in pesticide risk assessments. A wide variety of population model applications and resources on modeling techniques, evaluation and documentation can be found in the literature. In this paper, we add to these resources by introducing a systematic, transparent approach to developing population models. The decision guide that we propose is intended to help model developers systematically address data availability for their purpose and the steps that need to be taken in any model development. The resulting conceptual model includes the necessary complexity to address the model purpose on the basis of current understanding and available data. We provide specific guidance for the development of population models for herbaceous plant species in pesticide risk assessment and demonstrate the approach with an example of a conceptual model developed following the decision guide for herbicide risk assessment of Meads milkweed (Asclepias meadii), a species listed as threatened under the US Endangered Species Act. The decision guide specific to herbaceous plants demonstrates the details, but the general approach can be adapted for other species groups and management objectives. Population models provide a tool to link population-level dynamics, species and habitat characteristics as well as information about stressors in a single approach. Developing such models in a systematic, transparent way will increase their applicability and credibility, reduce development efforts, and result in models that are readily available for use in species management and risk assessments.

Development of Diagnostic Tools for Trace Organic Compounds and Multiple Stressors

This WERF sponsored research presents a preliminary screening process and ecological diagnostic approaches that could be used to help prioritize and evaluate treated wastewater-influenced sites that may be most at risk from trace organic chemical (TOrC) exposure. This work builds on the TOrC prioritization research completed earlier in this research and demonstrates how current diagnostic approaches used in the U.S. (CADDIS) and Canada (Environmental Effects Monitoring) could be extended to evaluate potential risks due to TOrCs. The screening process uses indicators in four categories: (1) wastewater influent and population served, (2) wastewater treatment characteristics, (3) ecological characteristics of the site, and (4) exposure or effects information from the site if available. The indicators included in the screening process are hypotheses, to be tested further using case studies in this research, and should not be taken as validated measures to be used to infer TOrC issues at a site. The diagnostic approach described in this research could be applied prospectively (could ecological effects due to TOrCs occur at my site?) and retrospectively (I have observed ecological effects at my site; are TOrCs a contributing cause?). However, given our current lack of knowledge concerning modes of action for many TOrCs, as well as the factors that determine whether TOrC effects on individuals are translated to community-level ecological effects, the diagnostic approach in this research focuses on retrospective applications at this time. The screening process has been used with some modification for sites in the Ohio Erie Drift Plain ecoregion and some of these, as well as other sites, will be evaluated using diagnostic approaches in Task 3 (case studies) of this research. A web-based database application ( ) has been developed for this project to help end users eventually search and evaluate TOrC data collected by many organizations in the U.S. and to assist in screening and diagnosing risks due to TOrCs. Comments are welcome on the various search features and metadata available for TOrCs within the current database. This title belongs to WERF Research Report Series . ISBN: 9781843395348 (eBook)

Diagnostic Tools to Evaluate Impacts of Trace Organic Compounds Final Report

With the advent of improved analytical detection capabilities, a variety of organic chemicals have been found in trace amounts (Trace Organic Chemicals, TOrCs) in surface waters, sediment, and fish tissue. These TOrCs include pharmaceuticals, personal care products, surfactants, and other currently unregulated chemicals. This WERF sponsored research presents a preliminary screening process and ecological diagnostic approaches that could be used to help prioritize and evaluate treated wastewater-influenced sites that may be most at risk from trace organic chemical (TOrC) exposure. Identifying or predicting ecological effects of TOrCs in typical aquatic systems is challenging, requiring a variety of tools that can diagnose effects at multiple scales of ecological organization. Development of a prioritization process is the goal of Task 1 of this research and the focus of this report. This research developed three approaches to prioritize TOrCs: 1) risk-based, 2) chemical persistence, bioaccumulation potential, and toxicity (PBT), and 3) a hybrid based on risk, persistence, and bioaccumulation potential. Using an occurrence database compiled from over 100 monitoring studies, the three prioritization approaches were applied to over 500 TOrCs that have been detected in water or effluent samples in the U.S. over the past 10 years. Types of TOrCs identified as high priority differed among approaches: steroids/hormones, pharmaceuticals, and surfactants comprised most of the high priority TOrCs based on risk while pesticides, industrial chemicals, and PAHs comprised most of the high priority TOrCs based on a PBT approach. Except for the synthetic hormones and steroids, results of all three prioritization approaches yielded only a few pharmaceuticals of high priority. Using a risk-based prioritization approach, predicted chronic toxicity endpoints were more sensitive than endpoints based on estrogenic activity for most TOrCs. The prioritization list(s) resulting from this work is not necessarily intended to be viewed as a list of compounds to be monitored or for which water quality criteria should be developed. The process of developing the list(s) is as important as the list(s) itself and the appropriate use of any resulting list(s) will depend largely on the goals of the user. This title belongs to WERF Research Report Series . ISBN: 9781843395478 (Print) ISBN: 9781780403335 (eBook)

Author's response to Shappell (2016)

Ltter to th e Ed to DEAR SIR: On behalf of myself and my co-authors, we thank Dr. Nancy Shappell for her interest in our article (Kapo et al. this issue) and for her efforts in suggesting andproviding an alternativemethod for visualizing the monitoring data and simulation results. Our case study compared available monitoring data for the United States to national modeled concentration distributions independently generated by the iSTREEM 1 model. We used a traditional cumulative distribution plot format to present the data because we felt it best met the primary objective and focus of our study (evaluating the similarity of modeled vs measured distributions) andwould be in a familiar and easily interpretable format for readers. However, we encourage users of the iSTREEM model to employ the data visualization format best suited to their particular research needs (including the example provided by Dr. Shappell), which can vary based on the preference of the researcher and the specific goals of a study.