Considerations for Development of Exposure Limits for Chemicals Encountered During Aircraft Operation.

BACKGROUND: Military aircrews' health status is critical to their mission readiness, as they perform physically and cognitively demanding tasks in nontraditional work environments. Research Objectives: Our objective is to develop a broad operational risk assessment framework and demonstrate its applicability to health risks to aircrews because of airborne chemical exposure, considering stressors such as heat and exertion. METHODS: Extrapolation of generic exposure standards to military aviation-specific conditions can include computation of risk-relevant internal dosimetry estimates by incorporating changes in breathing patterns and blood flow distribution because of aspects of the in-flight environment. We provide an example of the effects of exertion on peak blood concentrations of 1,2,4-trimethylbenzene computed using a physiologically based pharmacokinetic model. RESULTS: Existing published collections on the effects of flight-related stressors on breathing patterns and blood flow address only a limited number of stressors. Although data exist that can be used to develop operational exposure limits specific to military aircrew activities, efforts to integrate this information in specific chemical assessments have been limited. CONCLUSIONS: Efforts to develop operational exposure limits would benefit from guidance on how to make use of existing assessments and expanded databases of the impact of environmental stressors on adult human physiology.

The Environmental Protection Agency's Use of Community Involvement to Engage Communities at Superfund Sites.

The Environmental Protection Agency's (EPA) Superfund program was established to identify, assess and clean up the nation's worst hazardous waste sites to protect human health and the environment. Community involvement is an important part of the Superfund program for at least three reasons. First, involving communities in decision making at Superfund sites is a statutory requirement. Second, community involvement is important so that clean up decisions will support reuse in the surrounding community. Third, because even after cleanup many sites have residual contamination that warrants administrative and legal controls to protect health and the environment, community members should understand these controls to both help protect community members and any limitations on site reuse. Community feedback informs both proposed actions and local reuse decisions. While the EPA recognizes that the agency performs many activities that are helpful to support community involvement, there are areas in need of improvement and further research would be helpful for communities in the future.

The 2011 National Wetland Condition Assessment: overview and an invitation.

The first National Wetland Condition Assessment (NWCA) was conducted in 2011 by the US Environmental Protection Agency (USEPA) and its federal and state partners, using a survey design that allowed inference of results to national and regional scales. Vegetation, algae, soil, water chemistry, and hydrologic data were collected at each of 1138 locations across the conterminous United States (US). Ecological condition was assessed in relation to a disturbance gradient anchored by least disturbed (reference) and most disturbed sites identified using chemical, physical, and biological disturbance indices based on site-level data. A vegetation multimetric index (VMMI) was developed as an indicator of condition, and included four metrics: a floristic quality assessment index, relative importance of native plants, number of disturbance-tolerant plant species, and relative cover of native monocots. Potential stressors to wetland condition were identified and incorporated into two indicators of vegetation alteration, four indicators of hydrologic alteration, a soil heavy metal index, and a nonnative plant indicator and were used to quantify national and regional stressor extent, and the associated relative and attributable risk. Approximately 48 ± 6% of the national wetland area was found to be in good condition and 32 ± 6% in poor condition as defined by the VMMI. Across the conterminous US, approximately 20% of wetland area had high or very high stressor levels related to nonnative plants. Vegetation removal, hardening, and ditching stressors had the greatest extent of wetland area with high stressor levels, affecting 23-27% of the wetland area in the NWCA sampled population. The results from the 2016 NWCA will build on those from the 2011 assessment and initiate the ability to report on trends in addition to status. The data and tools produced by the NWCA can be used by others to further our knowledge of wetlands in the conterminous US.

Quantifying the extent of human disturbance activities and anthropogenic stressors in wetlands across the conterminous United States: results from the National Wetland Condition Assessment.

In 2011, the U.S. Environmental Protection Agency conducted the National Wetland Condition Assessment (NWCA) as part of the National Aquatic Resource Survey (NARS) program to determine the condition of wetlands across the 48 contiguous states of the United States (US). Sites were selected using a generalized random tessellated stratified (GRTS) probability design. We quantified the types, extent, and magnitude of human activities as indicators of potential stress on a sample of 1138 wetland sites representing a target population of 251,546 km2 of wetlands in the US. We used field observations of the presence and proximity of more than 50 pre-determined types of human activity to define two types of indices that quantify human influences on wetlands. We grouped these observations into five types of human activity (classes) and summed them within and across these classes to define five metrics and an overall Human Disturbance Activity Index (HDAI). We calculated six Anthropogenic Stress Indices (ASIs) by summing human disturbance activity observations within stressor categories according to their expected effect on each of six aspects of wetland condition. Based on repeat-visit data, the precision of these metrics and indices was sufficient for regional and national assessments. Among the six categories of stress assessed nationally, the percentage of wetland area having ASI levels indicating high stress levels ranged from 10% due to filling/erosional activities to 27% due to vegetation removal activities. The proportion of wetland area with no signs of human disturbance activity (HDAI = 0) within a 140-m diameter area varied widely among the different wetland ecoregions/types we assessed. No visible human disturbance activity was evident in 70% of estuarine wetlands, but among non-estuarine wetlands, only 8% of the wetland area in the West, 15% of the Interior Plains, 22% of the Coastal Plains, and 36% of the Eastern Mountains and Upper Midwest lacked visible evidence of disturbance. The woody wetlands of the West were the most highly stressed reporting group, with more than 75% of their wetland area subject to high levels of ditching, hardening, and vegetation removal. The NWCA offers a unique opportunity to quantify the type, intensity, and extent of human activities in and around wetlands and to assess their likely stress on wetland ecological functions, physical integrity, and overall condition at regional and continental scales.

Applying adaptive management and lessons learned from national assessments to address logistical challenges in the National Wetland Condition Assessment.

The National Wetland Condition Assessment (NWCA) is one of a series of probability-based National Aquatic Resource Surveys (NARS) conducted by the U.S. Environmental Protection Agency (USEPA) to provide a comprehensive assessment of the condition of the Nation's waters. Randomized design and standardized training and protocols allow USEPA to analyze data that are nationally consistent and regionally relevant. Each NARS assessment was preceded by careful consideration of key logistical elements that included pre-survey planning, training, sampling logistics, and laboratory analysis. Numerous state, tribal, and contractor crews were supported across the country for each assessment; sampling and sample analyses were tracked from initiation; laboratory analyses were completed at USEPA, state, regional, and contract laboratories; and the data analyses and reporting were completed by USEPA-led workgroups, states, and contractors. The complexity and difficulty of each step offered unique challenges and provided lessons learned for each of the NARS assessments. Major logistical elements for implementing large scale assessments that are constrained by sampling period and number and duration of visits are covered in this paper. These elements include sample transport, equipment and supplies, sampling and sample tracking, information management regional technical expertise, and a sound field training program. This paper describes how lessons from previous assessments were applied to the NWCA and how new challenges faced in the NWCA were addressed and carried forward into future surveys.

Foreword to the USEPA's National Wetland Condition Assessment Topical Collection.

The Environmental Protection Agency's (EPA) National Aquatic Resources Survey (NARS) is a 5-year ongoing cycle of nationwide aquatic resource surveys which provide a report card on the condition of our nation's waters. The surveys are performed using a randomized, statistically valid design and provide statistically robust data which are used to develop the reports. These reports assess how well existing pollution prevention programs are protecting those waters, and how to better target future protection efforts. This presentation will focus on the results and uses of the 2011 National Wetland Condition Assessment (NWCA) outcomes. Some of the outcomes from the NWCA include (1) robust multi-metric indices used to evaluate condition across varying wetland types, streams, and ecoregions and (2) physical, chemical, and biological indicators of stress (risk factors) which identify the factors which contribute most to poor condition. (3) A wealth of quality-assured, statistically valid data which can be mined to pursue other questions within both regulatory and non-regulatory programs by providing a more robust look at wetland and stream condition. There are a variety of ways in which knowledge of condition can be used to better evaluate environmental states and inform decision-making. Knowledge of risk factors, for example, can be used to prioritize restoration efforts to improve the health of streams and wetlands in poor condition, as well as to identify practices to be avoided in reviewing permit applications for work in waters. The use of multi-metric plant condition indices could be useful in better identifying achieved "lift" in wetland mitigation banks, as well as providing a more robust measure of mitigation or restoration success. It is our hope to generate some seeds for future thought and discussion on ways in which the products of these NARS surveys can enhance the protection and restoration of these aquatic resources.

Survey design to assess condition of wetlands in the United States.

The US Environmental Protection Agency (US EPA) initiated planning in 2007 and conducted field work in 2011 for the first National Wetland Condition Assessment (NWCA) as part of the National Aquatic Resource Surveys (NARS). It complements the US Fish and Wildlife Service (USFWS) National Wetland Status and Trends (S&T) program that estimates wetland acres nationally. The NWCA used a stratified, unequal probability survey design based on wetland information from S&T plots to select 900 sites for the conterminous 48 states. Based on site evaluation information, the NWCA estimates that there are 94.9 (± 6.20) million acres of wetlands in the NWCA target wetland population (reported in acres to be consistent with S&T). Not all of the estimated target population acres could be sampled due to accessibility and field issues. Based on the sites that could be sampled, the sampled population for the NWCA is estimated to be 62.2 (± 5.28) million acres of wetland area. Landowner denial for access was the main reason (24.7% ± 3.5%) for the sampled population being smaller than the target population, and physical inaccessibility was the second reason (6.8% ± 2.1%). The NWCA 2011 survey design was successful in enabling a national survey for wetland condition to be conducted and coordinated with the USFWS S&T survey of wetland extent. The NWCA 2016 survey design has been modified to address sample frame issues resulting from the difference in S&T focusing only on national estimates and NWCA focusing on national and regional estimates.

Striving for consistency in the National Wetland Condition Assessment: developing a reference condition approach for assessing wetlands at a continental scale.

One of the biggest challenges when conducting a continental-scale assessment of wetlands is setting appropriate expectations for the assessed sites. The challenge occurs for two reasons: (1) tremendous natural environmental heterogeneity exists within a continental landscape and (2) reference sites vary in quality both across and within major regions of the continent. We describe the process used to set reference expectations and define a disturbance gradient for the United States (US) Environmental Protection Agency's National Wetland Condition Assessment (NWCA). The NWCA employed a probability design and sampled 1138 wetland sites across the conterminous US to make an unbiased assessment of wetland condition. NWCA vegetation data were used to define 10 reporting groups based on ecoregion and wetland type that reduced the naturally occurring variation in wetland vegetation associated with continent-wide differences in biogeography. These reporting groups were used as a basis for defining quantitative criteria for least disturbed and most disturbed conditions and developing indices and thresholds for categories of ecological condition and disturbance. The NWCA vegetation assessment was based on a reference site approach, in which the least disturbed reference sites were used to establish benchmarks for assessing the condition of vegetation at other sites. Reference sites for each reporting group were identified by filtering NWCA sample data for disturbance using a series of abiotic variables. Ultimately, 277 least disturbed sites were used to set reference expectations for the NWCA. The NWCA provided a unique opportunity to improve our conceptual and technical understanding of how to best apply a reference condition approach to assessing wetlands across the US. These results will enhance the technical quality of future national assessments.

Exploring current read-across applications and needs among selected U.S. Federal Agencies.

Read-across is a well-established data gap-filling technique applied for regulatory purposes. In US Environmental Protection Agency's New Chemicals Program under TSCA, read-across has been used extensively for decades, however the extent of application and acceptance of read-across among U.S. federal agencies is less clear. In an effort to build read-across capacity, raise awareness of the state of the science, and work towards a harmonization of read-across approaches across U.S. agencies, a new read-across workgroup was established under the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM). This is one of several ad hoc groups ICCVAM has convened to implement the ICCVAM Strategic Roadmap. In this article, we outline the charge and scope of the workgroup and summarize the current applications, tools used, and needs of the agencies represented on the workgroup for read-across. Of the agencies surveyed, the Environmental Protection Agency had the greatest experience in using read-across whereas other agencies indicated that they would benefit from gaining a perspective of the landscape of the tools and available guidance. Two practical case studies are also described to illustrate how the read-across approaches applied by two agencies vary on account of decision context.

Organophosphate insecticide exposure: A clinical consideration of chlorpyrifos regulation.

BACKGROUND AND PURPOSE: In March 2017, the Environmental Protection Agency (EPA) reversed course on a proposal to ban the agricultural use of the organophosphate (OP) insecticide chlorpyrifos (CPF). The purpose of this article is to examine the evidence leading to this controversial decision and provide clinically applicable health promotion guidance for nurse practitioners on CPF exposure and risk reduction measures. METHODS: Environmental Protection Agency documents on CPF regulation and corresponding research referenced within the EPA reports are reviewed. Evidence-based health promotion strategies obtained through PubMed, CINAHL, Center for Disease Control and Prevention, and National Institutes of Health sources are summarized. CONCLUSIONS: Available data suggest a potential association between CPF exposure and adverse neurodevelopmental outcomes. Particularly vulnerable populations are pregnant women, children younger than two years, and agricultural workers. There may be genetic variability in susceptibility to environmental toxins. IMPLICATIONS FOR PRACTICE: Because of the extensive use of the OP CPF in agriculture and other community-based settings throughout the United States, nurse practitioners should be knowledgeable of the evidence regarding CPF exposure and be prepared to provide health promotion guidance to patients in clinical practice. Nurse practitioners should also consider their role in advocacy for healthy environments and the protection of vulnerable populations as it relates to agricultural insecticide exposure.

The Environmental Protection Agency in the Early Trump Administration: Prelude to Regulatory Capture.

We explore and contextualize changes at the Environmental Protection Agency (EPA) over the first 6 months of the Trump administration, arguing that its pro-business direction is enabling a form of regulatory capture. We draw on news articles, public documents, and a rapid response, multisited interview study of current and retired EPA employees to (1) document changes associated with the new administration, (2) contextualize and compare the current pro-business makeover with previous ones, and (3) publicly convey findings in a timely manner. The lengthy, combined experience of interviewees with previous Republican and Democratic administrations made them valuable analysts for assessing recent shifts at the Scott Pruitt-led EPA and the extent to which these shifts steer the EPA away from its stated mission to "protect human and environmental health." Considering the extent of its pro-business leanings in the absence of mitigating power from the legislative branch, we conclude that its regulatory capture has become likely-more so than at similar moments in the agency's 47-year history. The public and environmental health consequences of regulatory capture of the EPA will probably be severe and far-reaching.

The US Federal Tox21 Program: A strategic and operational plan for continued leadership.

The traditional approaches to toxicity testing have posed multiple challenges for evaluating the safety of commercial chemicals, pesticides, food additives/contaminants, and medical products.The challenges include number of chemicals that need to be tested, time and resource intensive nature of traditional toxicity tests, and unexpected adverse effects that occur in pharmaceutical clinical trials despite the extensive toxicological testing.Over a decade ago, the U.S. Environmental Protection Agency (EPA), National Toxicology Program (NTP), National Center for Advancing Translational Sciences (NCATS), and the Food and Drug Administration (FDA) formed a federal consortium for "Toxicology in the 21st Century" (Tox21) with a focus on developing and evaluating in vitro high-throughput screening (HTS) methods for hazard identification and providing mechanistic insights.The Tox21 consortium generated data on thousands of pharmaceuticals and datapoor chemicals, developed better understanding of the limits and applications of in vitro methods, and enabled incorporation of HTS data into regulatory decisions. To more broadly address the challenges in toxicology, Tox21 has developed a new strategic and operational plan that expands the focus of its research activities. The new focus areas include developing an expanded portfolio of alternative test systems, addressing technical limitations of in vitrotest systems, curating legacy in vivo toxicity testing data, establishing scientific confidence in the in vitrotest systems, and refining alternative methods for characterizing pharmacokinetics and in vitro assay disposition.The new Tox21 strategic and operational plan addresses key challenges to advance toxicology testing and will benefit both the organizations involved and the toxicology community.