Despite the unique characteristics of urban forests, the motivating factors of urban forest visitors have not been clearly differentiated from other types of the forest resource. This study aims to identify the motivating factors of urban forest visitors, using latent Dirichlet allocation (LDA) topic modeling based on social big data. A total of 57,449 cases of social text data from social blogs containing the keyword “urban forest” were collected from Naver and Daum, the major search engines in South Korea. Then, 17,229 cases were excluded using morpheme analysis and stop word elimination; 40,110 cases were analyzed to identify the motivating factors of urban forest visitors through LDA topic modeling. Seven motivating factors—“Cafe-related Walk”, “Healing Trip”, “Daily Leisure”, “Family Trip”, “Wonderful View”, “Clean Space”, and “Exhibition and Photography”—were extracted; each contained five keywords. This study elucidates the role of forests as a place for healing, leisure, and daily exercise. The results suggest that efforts should be made toward developing various programs regarding the basic functionality of urban forests as a natural resource and a unique place to support a diversity of leisure and cultural activities. According to the UN DESA , 55% of Although there has not been a firmly agreed definition of urban forests, it is commonly agreed that urban forests differ from forests outside urban areas in terms of their existence in dense areas of human settlements such as large cities and towns . This stThe recent rise in concerns for various diseases and pollution along with the COVID-19 pandemic have enhanced healthcare interests in South Korea . CompareThe specific factors that motivate urban forest visits are being prioritized to highlight the functions and benefits of urban forests and to develop suitable programs for visitors. For these reasons, studies have investigated forest-related policies, the positive effects of forests on health, and the economic impact of forests. However, there is a lack of independent studies focusing only on the motivation of visitors to urban forests. In fact, because the actual urban forest visitors prefer short-distance travel to places in close proximity to city centers or urban living districts, this type of visit needs to be distinguished from the visit to conventional forests such as healing forests, natural recreation forests, and national parks. Most studies on forest resources investigated the visits to the aforementioned conventional forests  rather than the urban forests themselves ,7,8.Previous studies identifying the factors that motivate forest visitors have generally used a conventional scale development approach that relies heavily on the literature review of motivations, the survey of visitors, and in-depth interviews ,10. HoweThus, this study aimed to identify the factors leading to the visit to urban forests through a novel method based on social big data that allows a large sample size, including the visitors’ experience of different urban forest types and the representability of the temporal range. Specifically, the text data of social media containing the keyword “urban forest” were extracted as big data, and latent Dirichlet allocation (LDA) topic modeling was applied to draw each specific topic (theme) to identify the factors that motivate urban forest visitors. Since city residents are likely to experience the urban forests on a more regular basis than other natural forests outside urban areas , it is eUrban forests provide leisure services such as recreation and physical and psychological recovery to the urban residents who are prone to various psychological and emotional problems such as stress; they also function as ecosystems. Therefore, the importance of urban forests has been emphasized as a means to solve the different problems induced by the complexity of urban living .An urban green space (UGS) functions as a critical resource that alleviates the negative psychological and emotional effects of urban life ,12,13. PWith the recognition of the importance of UGS, efforts have been made to provide a diversity of benefits related to urban forests to urban residents in South Korea. In June 2020, urban forests were defined as “forests and trees produced and managed to enhance the health and recreation as well as emotional cultivation and field experience of people in an urban area”, through the enactment of the Regulation of the Production and Management of Urban Forests, etc., while various policies are underway towards the use of urban forests as a place for refreshing environment, rest, and recreation, as well as health improvement and emotional cultivation. Furthermore, several projects for urban forest production focus on preventing the diffusion of fine dust from the source throughout the living district and reducing the fine dust concentration, thereby facilitating the supply of clean air . VariousAs such, the interest in applying urban forests in leisure activities has increased, but so far, only a few independent studies have been conducted regarding the motivating factors of visiting urban forests that are uniquely distinguished from other forests as the resource closely related to urban residents, while many similar studies have reported on the conventional motivations behind forest resources such as green areas, forestry, healing forests, and national parks.The factors that motivate urban forest visitors were analyzed in previous studies from various perspectives, as they targeted visitors to urban forestry or UGS. Studies regarding the factors that motivate the visit based on the review of papers published in South Korea and overseas have mainly included those on urban forest, forest park, national park, and urban green space. The scope of previous studies on urban forests included urban forests, healing forests, natural recreation forests, green areas, and national parks. Analyzing the previous studies showed that the identified factors in general could be accounted for by the push and pull dynamics based on tourism motivation, a motivation theory. The push factors indicate the internal factors of motivation, including escape from daily life, rest, respect, health, and adventure-related desires. The pull factors indicate the external factors of motivation including tourism resource, tourism facility, novelty, convenience, and reputation . In manyVisiting an urban forest may satiate the need for privacy among urban dwellers . Pan andMost studies conducted in South Korea have focused on the motivation to visit healing forests. Nam and Lee’s  study onThe motivations related to natural recreation forests were categorized in a study on hiking tourists as part of nature-based tourism, as follows: enjoying the natural environment, escaping from daily routine, new trips, healthy life, and a sense of intimacy . In a stStigsdotter and Grahn  showed tFinally, Uysal, McDonald, and Martin  reportedAs discussed before, the motivating factors of visiting forest resources could not be clearly differentiated despite the unique characteristics of each forest resource. The reason may be the use of the conventional scale-development method, where the items are first extracted from previous studies on forest resources to identify the motivating factors; then, the final factors are determined through a survey of actual visitors. In other words, since most motivation-related studies rely on the broad frame of motivating factors that already secured validity and reliability, it would have been difficult to derive differentiated factors. Moreover, the factors analyzed based on a survey present a challenge of adequate sample size to reflect the diverse motivating factors of visiting forest resources. Another limitation comes from the study being based on a cross-sectional design, as the survey is performed at a specific time, preventing the variation in motivating factors at each different time of visit to be reflected.For these reasons, this study used social data containing the experience of visiting an urban forest obtained from social media (blogs) that guarantee adequate samples, coverage of the wide range of time, and minimization of subjective judgment for extracting the motivating factors of visiting urban forests.The decision to visit a specific destination is influenced by experiential data in social media, with social media reviews becoming increasingly important. Accordingly, research interest in understanding visitors’ various behaviors based on social media data has continuously increased ,25. HencHowever, as previously described, studies regarding the motivation to visit urban forests have mainly used conventional methods  with consequent limitations such as the difficulty in analyzing the variations over time due to the samples collected for a set period and the errors in generalization due to inadequate sample size. The use of social media data could be an alternative to overcome a number of limitations related to data collection that frequently occur when applying conventional methods . FurtherTo identify the motivating factors of urban forest visitors, big data containing visitors’ experiences were collected. Blog is an important medium that relays information regarding the topic of interest easily and rapidly, while opinions can be shared and goods or services can be selected. Thus, two websites with accumulated data on visitors’ experiences, Naver and Daum, with 60% share of portal sites in South Korea based on 2020, were selected, and the entire text data from the blogs that contain the keyword “urban forest” were collected for the period between 1 July 2019 and 30 June 2020. The 38,056 cases of the urban forest blog data from the most recent year and 19,393 cases of the data of 11 forests selected and promoted by the Korea Forest Service were collected, totaling 57,449 cases of data samples.The method of data collection was the Python-based Web Crawler program run independently in this study, and the “Web Title” and “Meta Tag Description” of the blogs searched based on the keyword “urban forest” were collected.After the cleaning the first collected set of 57,449 cases based on the procedures of big data analysis, the final 40,110 cases were used in the analysis. Without appropriate pre-processing, the collected data may pose problems of incomplete data that lack a necessary attribute, noisy data that show an abnormal value outside the set scope, and inconsistent data that may arise in compiling several datasets . The goaIn the first cleaning process, texts that did not agree with the study purpose, such as advertisements , were eliminated. Texts related to real estate, rent, studio, sales, lease, or monthly rent were excluded based on the related regional posts and keywords, as they may add other forms of meanings than the intended ones if left alongside the texts related to the keyword “urban forest”. In this way, the data were cleaned so that only the topic (factor) related to “urban forest” with an intact meaning could be drawn.A blogger may write the contents related to the actual experience and review as well as marketing contents for commercial purposes, hence the keywords, despite containing “urban forest”, could lead to an unrelated, commercial blog. Therefore, it is crucial to perform data cleaning prior to the analysis.Prior to analysis, the MeCab was used to construct the “User Dictionary”, whereby the process of structural conversion of the informal data was performed. Following the conversion to the document-term matrix, the open api KoNLPy was used for morpheme analysis, a process of segmentation of phrases or sentences into the smallest semantic unit of morphemes, including both the lexical and syntactic senses. The term “morpheme” means the “first semantic unit”.The process of “User Dictionary—Morpheme Analysis—Stop Word Elimination” is crucial for extracting accurate results in line with the study purpose, and during the process, care should be taken to prevent data loss. Each separated word was screened for common nouns, proper nouns, bound nouns, counter nouns, numerals, and pronouns, while adjectives  and post-positions as well as special letters, emoticons, symbols, and foreign words are eliminated to leave the pure Korean morphemes.The process involves stop word elimination, as stop words do not confer significant contextual meanings despite being essential components of sentences in the processing of natural language. The names of specific brands or regions  that show no association with the study purpose, despite the high frequency of detection, were eliminated. Words unrelated to the factors of urban forest visitors  were repeatedly extracted to be eliminated.The clean text data was applied to the LDA topic modeling, a method of natural language processing, to draw the motivating factors of urban forest visitors. The unsupervised problem method was used to identify the factors within a vast scope of data. In the context of LDA modeling, generally boxes are referred as “plates” which represents replicates. In other words, replicates represent documents in outer plate. Inner plate represents the repeated choice of topics and words within a document, where the marginal distribution of a document is obtained by the repeated choices of the converted document-term matrix . FinallyLDA topic modeling automatically extracts specific topics, issues, or theme groups that represent a given set of texts, with a focus on the pattern of concurrently used keywords present in the text data. Here, a topic may be viewed as a group of words sharing similar senses with a high probability of being detected together. The method allows the extraction of potential topics (factors) based on the statistical analysis of the frequency of words within the text data enabling frame analysis, which is useful for relatively quickly understanding the online community and inferring possible trends within the community . NotablySuch an algorithm is especially useful for identifying hidden topics and themes based on the word co-occurrence for each document in the corpus. It can be applied when the task requires the analysis of topics across a large number of documents since it is relatively simple for a person to analyze the topics in one or two documents, but the analysis of topics across hundreds or thousands of different documents is not easy. In addition, topic modeling is a good way to “let the text talk” because the identified topics do not depend on the evaluators’ individual perspectives or experiences. Moreover, there are numerous possible extensions of LDA, hence LDA topic modeling has been recently applied across fields ,33,34. IThe topics (factors) were drawn from the keywords belonging to the set clusters through discussions between the present investigator and the authors of previous studies. Specifically, based on the words showing high frequency, the words with high correlation were analyzed for probability, and each topic cluster was defined according to the probability distribution (cosine coefficient), which was then named as the theme word to deduce a total of seven topics. As a conventional procedure in LDA-based topic identification, each topic was manually named after analyzing the words included in topics . To ensuWords with a high vector-to-vector correlation were grouped according to the score. Based on the result and throughout the agreement among researchers, the topics of the group were named. Thus, the seven identified topics (factors) were “Cafe-related Walk”, “Healing Trip”, “Daily Leisure”, “Family Trip”, “Wonderful View”, “Clean Space”, and “Exhibition and Photography”. The first motivating factor, “Cafe-related Walk” contained the keywords “cafe, bicycle road, cottage, coffee, road, trip, and night.” Based on the keyword “cafe”, the connection may be made to “bicycle road”, “coffee”, and “trip”, which can indicate the coffee enjoyed at a cafe, a trip on a bicycle, and a walk along the road. Koo et al.’s  survey oThe second motivating factor, “Healing Trip” contained the keywords “trip, summer, travel site, healing, scenery, nature, and photography”. Based on these keywords, visitors to urban forests may be interpreted as visiting the travel site mainly during summer to enjoy the natural scenery and take photographs, and as indicated by the word “healing” that corresponds to an internal motivation for rest, health, and personal desire, the visitors showed a strong correlation with leisure, such as a healing trip, whereby they could photograph the beautiful natural scenery.The third motivating factor, “Daily Leisure” contained the keywords “cafe, street, life, home, location, walk, and vicinity”. The keyword “cafe” here indicated a different meaning from the one contained in “Cafe-related Walk”, and while it exhibited the highest score, the word may be interpreted to describe a daily life in an urban area. As the meaning was related to walking along the streets surrounding the residential area, the theme was closer to daily leisure than to trip. Visitors can be interpreted as visiting the forest as part of daily leisure and spending time in the vicinity of cafes close to home.The fourth motivating factor, “Family Trip” contained the keywords “gourmet, tourism, trip, location, sea, family, and course”. Based on the keyword “family”, the main motivating factors can be interpreted as the visit to gourmet restaurants, tourism, and trip. The theme is closer to trip than daily leisure, and visitors can be seen to visit the forest to enjoy a gourmet restaurant nearby or as part of tourism or trip.The fifth motivating factor, “Wonderful View” contained the keywords “famous site, city, autumn, maple, dream, tree, environment”. It is characterized by the goal of visiting the famous forest in the suburban area, enjoying the beautiful scenery of the season. The keywords “autumn”, “maple”, and “tree”, in particular, indicated the scenery of a beautiful forest as a famous site in autumn. This result is supported by a previous study  showing The sixth motivating factor, “Clean Space”, contained the keywords “fine dust, itinerary, park, citizen, tree, river, sea”. A notable keyword among them is “fine dust” that may indicate the keywords “park”, “tree”, “river”, and “sea” as external factors of motivation to be away from the city. The number of tourists leaving in search for a natural site known to have refreshing air is on the rise, and with increased interest in rest and healthcare, the goal of visiting an urban forest may be interpreted as the desire to visit a clean space.The seventh motivating factor, “Exhibition and Photography”, contained the keywords “exhibition, photography, gourmet, popularity, display, winter, and nature”. The exhibitions related to forests and the goal of photography motivated urban forest visitors. In fact, an increasing trend of visit was found for exhibition galleries, museums, and experience centers surrounding urban forests, and as events such as urban forest cultural experience are being held, the goal of the visitors may be interpreted as the photographing of a popular gourmet restaurant or famous site, and the theme word was named as “Exhibition and Photography”.To investigate the motivating factors of urban forests visitors, this study used social big data from Naver and Daum blogs with 60% share of portal sites in South Korea (based on 2020). A total of 57,449 cases of data from 2019 to 2020 were collected from the blogs related to urban forest visitors; after data cleaning, the final 40,110 cases of data were used to extract the motivating factors of urban forest visitors through text mining and LDA topic modeling techniques. Based on these results, pedagogical and practical implications were drawn.First, to identify the motivating factors of urban forest visitors, no factor was predetermined, and the factors were extracted from the data of visitor experience on the websites that were collected and analyzed comprehensively. In this way, methodological efforts were made to minimize the subjective judgment frequently observed in conventional scale-development methods that use literature review and in-depth interview to extract initial factors and in turn, conduct survey and exploratory or confirmatory factor analysis to finalize major factors.Second, in previous studies applying conventional factor analysis, the small sample size posed limitations due to time and cost constraints; in this study, the use of continuously accumulated social data allowed the collection of a large body of samples in a short period, and the limitation of spatial range was possibly transiently overcome. For this, the target sites were not urban forests, forestry, mountains, and green areas in a specific region, but by using social big data and the keyword “urban forest”, a more extensive scope of regions could be analyzed.Third, while limitations were found in previous studies based on a cross-sectional design and with a focus on a transient time, the LDA topic modeling in this study allowed the incorporation of temporal variations that reflect a wide scope of time to provide the data through which the motivating factors could be analyzed based on the visitors’ experiences. Urban forest visitors in modern society are influenced by online media, but only a few studies have used social data. Thus, the academic significance of this study lies in suggesting a novel method of analysis based on social media data. In addition, using LDA topic modeling, this study contributed to introducing more concrete motivating factors of urban forest visitors. Unlike other forest-related studies, this study specially presented the motivating factors related to tourism and leisure activities in detail such as ‘café-related walk’, ‘family trip’, etc. Based on the findings, the study was able to propose diverse insights and perspectives for designing and managing urban forests.An overall interpretation of the results for the motivating factors of urban forest visitors showed that due to the recent phenomenon of fine dust, the preference of visitors towards clean space has increased, while most urban forest visitors walk around cafes or enjoy the scenery. The themes of “Healing” and “Photography” as daily leisure or time in nature (forest) were shown to be preferred by visitors to urban forests. Based on the motivating factors identified from social big data, the following practical implications are suggested.First, among the motivating factors of urban forest visitors, “Cafe-related Walk” and “Daily Leisure” were both found to be based on the keyword “cafe”. The results implied that many tourists visited an urban forest to visit a nearby café. The results showed that their motivations to visit urban forests were to take a trip on a bicycle, enjoy daily leisure activities such as walking, and enjoy the leisure of drinking coffee at a cafe. Thus, accessibility to urban forests may be improved through the development of tourism packages connecting urban forests and cafes and the construction of roads such as bicycle roads around urban forests, as urban forest visitors preferred daily leisure.Second, “Healing Trip” and “Clean Space” clearly indicated the increased number of people seeking the healing of the body and mind and the clean space without fine dust, in line with the recent increase in the desires for rest and health due to the COVID-19 pandemic and the find dust phenomenon. As such, marketing managers should make efforts to highlight the benefits of urban forests as a clean space without finding dust and a place for the slow healing of the body and mind, while visitors may take the rest in nature and photograph the beautiful scenery.Third, “Family Trip” and “Wonderful View” showed that, for urban forest visitors, the tour of gourmet restaurants and wonderful view were critical motivating factors. The urban forests known as famous sites were visited for the beauty of a specific season as indicated by the keywords “autumn”, “maple”, and “tree”, while the goals of the family in visiting urban forests were the tour of gourmet restaurants and trip. Thus, to increase the number of visitors to urban forests, ways should be sought to introduce accommodations for family visitors together and promote famous and beautiful gourmet restaurants and historic sites.Fourth, “exhibition” and” photography” were found among the motivating factors to indicate the importance of exhibitions and photography related to urban forests. The exhibition galleries, museums, and experience centers related to urban forests as well as events such as urban forest cultural experience contributed to these themes as important motivating factors. The Green Walking Project in the UK contains photography, meditation, and forest experience as part of a program with flexibility for modification in accordance with the circumstances in the field . In refeLast but not least, the benefit of urban forests needs to be mentioned. The results of this study showed that urban forests can play important roles in not only improving urban dwellers’ public health such as physical and mental health but also increasing leisure and recreational activities. In particular, the study revealed that urban forests can serve as a tourism or leisure destination in the city beyond simply providing a green space for rest or healing. Looking at the collected text data, many visitors frequently used the word ‘travel’ and ‘trip’ concerning visiting urban forests. This might mean that not only urban residents living close to urban forests but people living farther than expected can benefit from urban forests. With regards to the health impact of urban forests, as Gianfredi et al.’s  recent sWith regards to the limitation of this study, the motivating factors based on the characteristics of urban forests in each region or administrative district could not be analyzed as the factors were extracted from the social big data-based web data that had been comprehensively collected. Nevertheless, the general factors that motivate the visit to urban forests across the nation can be identified extensively. For example, the urban forests within the city and in a suburban area may vary in terms of the location and travel range to affect motivation, and as each region or administrative district has different characteristics, it may be difficult to generalize the results of this study. More focused and specific studies should be conducted to determine the general motivating factors of urban forest visitors and to suggest a paradigm through which conventional methods are complemented in various ways. Further studies should also continue to investigate the differences between the forests within the city and in a suburban area and the regional characteristics or the unique features of each urban forest to determine the various motivating factors, which will lead to greater academic significance.The information analyzed might have a sample bias because all the samples collected were visitors who are encouraged to post their experiences online after visiting urban forests. This means that those visitors who are less active to leave their comments on blogs might have been neglected, which in turn, results that the motivating factors extracted may not be fully representative of all urban forest visitors. To reduce the bias, it is suggested to use the mixed method that incorporates both text mining and in-depth interview in future studies. In addition, the study was conducted only in one geographical context and, balanced sampling considering demographic distribution such as age, gender, educational level, etc., was not performed. This may mean that the findings and implications may not fully apply to other geographical settings. Therefore, it is suggested to conduct cross-region or cross-cultural studies to validate the results of this study and to provide more insightful explanations about the cultural and geographical impact on motivations.


Recognition of the value of “social accountability” to improve health systems performance and to address health inequities, has increased over the last decades, with different schools of thought engaging in robust dialogue. This article explores the tensions between health policy and systems research and practice on the one hand, and health equity-focussed activism on the other, as distinct yet interacting processes that have both been impacted by the shock effects of the Covid-19 pandemic. This extended commentary brings multidisciplinary voices seeking to look back at health systems history and fundamental social-institutional systems’ behaviors in order to contextualize these current debates over how best to push social accountability efforts forward.There is a documented history of tension between long and short processes of international health cooperation and intervention. Social accountability approaches, as a more recent strategy to improve health systems performance, intersect with this overarching history of negotiation between differently situated actors both global and local on whether to pursue sustained, slow, often community-driven change or to focus on rapid, measurable, often top-down interventions. Covid-19, as a global public health emergency, resulted in calls for urgent action which have unsurprisingly displaced some of the energy and aspiration for systemic transformation processes. A combination of accountability approaches and mechanisms have their own legitimacy in fostering health systems change, demanding collaboration between those that move both fast and slow, top-down and bottom-up.We argue that social accountability, much like all efforts to strengthen health systems, is “everybody’s business” and that we must understand better the historical processes that have shaped the field of practice over time to move forward. These differences of perspective, knowledge-base and positioning vis-a-vis interventions or longer-term political commitment should not drive a conflict of legitimacy but instead be named, subsequently enabling the development of a shared code of conduct that applies to the breadth of actors involved in social accountability work. If we are concerned about the state of/status of social accountability within the context of “building back better” we must approach collaboration with a willingness to create dialogue across distinct disciplinary, technical and politically-informed ways of working. Over the last two decades, there has been increasing use of “social accountability” language and practices in global health, particularly in the area of health policy and systems research and interventions. In our use of the term “social accountability” in a contemporary context we refer to the broad range of strategies that are used to bolster community engagement and to hold public and private actors to account within the context of the public health sector, while noting that many health systems are pluralistic in nature and not wholly  publicly controlled or owned. Social accountability organizes constituencies and information to generate dialogue or confrontation, and can aim to do different things, such as: address equity issues, quality of care, and unequal power relationships between citizens, care providers, health systems managers, and policy makers. Alternatively it can be mobilized to draw attention to service providers’ blind spots and/or broken public commitments. This extended commentary explores the tensions, actual or perceived, between health policy and systems research interventions and program implementation on the one hand (the world of “technicians”), and health equity-focussed activism on the other (the world of “activists”), as distinct yet interacting fields that have both been impacted by the shock effects of the Covid-19 pandemic. We use “technicians” and “activists” as short-hand for schools of thoughts or patterns of approach, recognizing that these terms are an over-simplification of what is in fact a more complex reality of shifting roles and strategies.With increased global health attention to social accountability, health program actors have moved closer to the spaces where health equity activists, local, ‘global’ and in-between, articulate their demands for accountability on governments and public duty-bearers. The authors of this commentary are part of the Community of Practice (CoP) on measuring social accountability and health outcomes convened by the Department of Sexual and Reproductive Health and Research based at the World Health Organization. As researchers coming to this topic with different foundational framings – a social historian and participatory ethnographer (EN), a health systems researcher working within a national context where the history of health systems creation marked a political turning point (VS), and health systems researchers and practitioners both internationally and nationally situated — we have seen these two fields of activity - health systems research and practice, and health equity-focussed activism—develop over time as distinct, yet interacting, processes. More recently, we have witnessed the Covid-19 pandemic as a ‘shock event’ that has disrupted the world and subsequently these fields of activity in which we, the authors, are differently involved. The wide range of public health and health systems responses to Covid-19 have taken center stage, resulting initially in a the dominance of command-and-control responses, while participatory and community-led responses emerged more slowly, or rather, with less international attention [Given the already-existing challenges in maintaining focus and momentum across a diverse range of social accountability efforts in global health, we seek to look back, look forward, and discern what this moment offers in terms of strengthening an equity-focussed agenda.Historical perspectives can help us better understand the current moment for social accountability in health. Accountability theorists and health systems researchers talk about the importance of historical context, but there is often little effort made to deepen understandings of how the past has shaped the systems, structures and logics of the present. International development and global health actors, naturally engaged in planning and forecasting, can have tremendous blindspots when it comes to the past failures and unmet promises of their own institutions or within their fields of practice –5. One oThis is not the place to elaborate on the breadth of historical research that could reasonably inform current social accountability approaches, but rather a reflection on the value of integrating long- and short-term perspectives in social accountability processes, as well as giving attention to intergenerational commitments to social justice. Short-term versus long-term ways of working have emerged in different areas of global health: service delivery and capacity building, system strengthening, technically-driven health interventions and community-engaged, participatory public health approaches. It is important to recognize that the tensions between these distinct modes of practice are not new phenomena in international health cooperation. Though this commentary is not a bibliographic review, it draws on one authors’ (EN’s) historical research over time related to international public health/global health, as well as an intergration of historical perspectives into a contemporary health research practice. This commentary reflects an emerging and expanding field of literature that has identified some of the origins of, and the repeating nature of, tensions between “activist” and “technical” approaches to health from the interwar period through to the turn of the twenty-first century –9.We begin with a brief review of relevant historiography on the emergence of “health systems” and “accountability” as concepts and as fields of practice. Prior to the spread of “health systems” approaches in international public health (circa mid 1960s), transnational networks of public health/sanitarian activists and technicians recognized the interrelationship between local infrastructure, sanitation, education, economic status, agricultural development, nutrition as linked to health outcomes. As early as 1937, at the Bandung “Intergovernmental Conference of Far Eastern Countries on Rural Hygiene” one can identify the emergence of “intersectoral and interagency cooperation” across fields of practice, distinct disciplines, and areas of expertise with the aim of addressing shared public health challenges . The ideHealth by the People, an edited compendium of community public health initiatives which highlighted the grassroots work of social medicine activists in Latin America, South East Asia, the Middle East and China [In 1967, the WHO set up the in-house Division of Research in Epidemiology and Communication Sciences (RECS) to develop new planning methods for health “systems” in “developing” countries, led by Kenneth Newell, and drawing on the experience and expertise of innovators in multidisciplinary planning approaches from diverse country contexts [nd China . For thend China .The Alma Ata moment, contrary to how it is portrayed in global health literature, marked the beginning of a shift away from “horizontal” or community-led, multi-sectoral, ‘activist- inclusive approaches to health systems development within international/global health circles. By 1979, within the WHO, UNICEF and amongst Western global health leadership, the tide had turned towards a politically neutral and economically feasible “selective” approach to Primary Health Care , 14, 15.The development of systems thinking and the tensions between “activist” and “technician” led approaches to public health are important precedents to understand contemporary accountability ecosystems framings. Over time, conflicts have emerged between health systems strengthening researchers and practitioners on the one hand, and health equity-focussed activists on the other, the former associated with timebound project cycles and the latter with generational societal transformations , 20. A “Prior to the the Covid-19 pandemic, accountability theorists and practitioners in health systems were concerned with the rise of digital technologies, the increased corporatization of health systems and the concomitant challenges of embedding accountability mechanisms within institutions, regulatory powers, professional associations, and at an international level – a shifting group of global health governance leaders. Within the context of the Covid-19 crisis, as with most emergencies, the first instinct has been to focus on short-term response and “command and control” interventions, at the expense of measures which may have provided more community engagement and involvement in the development of prevention and risk management strategies . While tWithout knowing the future development of the Covid-19 pandemic, we know that it will not be the last pandemic or global health emergency . To dateAccountability takes many forms  of which social accountability is just one element , 24. In We can now examine where perspectives diverge, in spite of this common ground. Social accountability activists, whether local, national or transnational in practice, see problematic hierarchies of power, broken institutional commitments, or at a minimum public service provider blind spots, as a starting point for change. They may focus on health systems changes specifically, but will often look more broadly at societal arrangements and structural inequalities to determine which issues matter most, to whom, and how they should be addressed. By contrast, heath systems technicians, be they working for on behalf of donor governments, philanthropic funders, or working as project implementers, may perceive gaps in performance relative to the investments made by the institutitions or governments for whom they work and be expected to address and resolve problems that have proved intractable to prior health systems professionals. Within the field of what is still considered “global” health, funding for health systems strengthening  has long been, and remains a small slice of the overall funding pie, though by comparison with the resources available to local civil society organizations and activist groups, these funds are relatively substantial .Table Most dichotomies oversimplify and Table The Covid-19 pandemic triggered a ‘crisis’ response as global health emergencies often do , 23, 40.Those concerned about the state of social accountability efforts within the context of pandemic response and beyond must learn from our international public health forebearers the value of both ‘technicians’ and ‘activists’ in driving health systems change. In a context of rapid change, including processes already underway prior to Covid-19 such as shifts in global political leadership and the emergence of increasingly mixed health systems, accountability efforts aimed at addressing health inequities are all the more crucial.prior to, or in anticipation of, future disruptions and shocks. Those working in the social accountability space may have different methodological tools and experiential knowledge to contribute, but without drawing on the fullest spectrum of human creativity and problem-solving capacity, the effort to address longstanding health systems inadequacies will remain stunted.In considering the impact of Covid-19 within the much longer time scale of international public health cooperation and health systems development, we suggest that social accountability should be pursued Staying with the construct social accountability “technicians” and “activists” can we discern a shared set of values or “code of practice” to help shift towards more effective collaboration? We conclude with some suggestions.“First do no harm” and “building synergies” remain valid principles, although their operationalization in practice is debated. A step in this direction may be to accept the plurality of our perspectives, and recognize the legitimacy of differently-framed agendas and diverse knowledges. Working across distinct academic disciplines, diverse forms of technical and professional expertise, and institutional cultures, let alone meaningfully incorporating indigenous and non-Western knowledge and practice, requires humility, openness and a willingness to be made uncomfortable when confronted with the limitations of one’s own assumptions. That said, when we cast our eye over the broad sweep of health systems history and the longstanding tensions between those who proffer “vertical”  versus “horizontal”  approaches to public health, it is clear that there is no one model way of working. Social accountability efforts oriented towards improving health equity demand dialogic and relational approaches from both “technicians” and “activists” even if at times this dialogue proves oppositional and fraught .For activists, the attention of “technicians” is an acknowledgement of their own success in demonstrating the value of social accountability to improving meaningful community engagement in health systems improvements. In seeking alliances to achieve time-bound targets with the support and funding of external interventions, social accountability activists can still leverage these opportunities for learning and coalition building, while recognizing that cooptation—institutional or personal--are ever-present challenges. On the other hand, donor agencies, health systems planners and managers of externally-funded health projects intervening in social accountability processes should recognize the disruption that their short-term work brings. Such technicians should be more attentive to the history of past health systems efforts both specific to the contexts where they work, as well as within the broader landscape of international public health cooperation before steaming ahead with “new” innovations in design and approach. Respect for endogenous processes and local perspectives should be an active and ongoing commitment. What this history teaches us is that working towards a collaborative “middle” ground is an ongoing learning process, one that is not devoid of confrontation or dissent. As with all health systems strengthening interventions, further illuminated by the wide-ranging impacts of Covid-19, social accountability is “everybody’s business” . To do b


Toxic chemicals — “toxicants” — have been studied and regulated as single entities, and, carcinogens aside, almost all toxicants, single or mixed and however altered, have been thought harmless in very low doses or very weak concentrations. Yet much work in recent decades has shown that toxicants can injure wildlife, laboratory animals, and humans following exposures previously expected to be harmless. Additional work has shown that toxicants can act not only individually and cumulatively but also collectively and even synergistically and that they affect disadvantaged communities inordinately — and therefore, as argued by reformers, unjustly. As late as December 2016, the last full month before the inauguration of a president promising to rescind major environmental regulations, the United States federal environmental-health establishment, as led by the Environmental Protection Agency (EPA), had not developed coherent strategies to mitigate such risks, to alert the public to their plausibility, or to advise leadership in government and industry about their implications. To understand why, we examined archival materials, reviewed online databases, read internal industry communications, and interviewed experts. We confirmed that external constraints, statutory and judicial, had been in place prior to EPA’s earliest interest in mixture toxicity, but we found no overt effort, certainly no successful effort, to loosen those constraints. We also found internal constraints: concerns that fully committing to the study of complex mixtures involving numerous toxicants would lead to methodological drift within the toxicological community and that trying to act on insights from such study could lead only to regulatory futility. Interaction of these constraints, external and internal, shielded the EPA by circumscribing its responsibilities and by impeding movement toward paradigmatic adjustment, but it also perpetuated scientifically dubious policies, such as those limiting the evaluation of commercial chemical formulations, including pesticide formulations, to only those ingredients said by their manufacturers to be active. In this context, regulators’ disregard of synergism contrasted irreconcilably with biocide manufacturers’ understanding that synergism enhanced lethality and patentability. In the end, an effective national response to mixture toxicity, cumulative risk, and environmental injustice did not emerge. In parallel, though, the National Institute of Environmental Health Sciences, which was less constrained, pursued with scientific investigation what the EPA had not pursued with regulatory action. Toxic chemicals — “toxicants” — in environmental media act and interact and are acted upon, some persisting unchanged, others changing predictably or unpredictably, uncounted numbers mixing in uncontrolled proportions with numerous traces co-accumulating in animals, including humans, with low-dose individual and synergistic effects reported by reputable laboratories. These facts and their implications have been studied for decades , in receMixture toxicity, cumulative risk, and related findings — low-dose effects, synergism, endocrine disruption, inordinate exposures in poorer-paying jobs and poorer neighborhoods — have elicited various responses: disinterest, dismissal, confusion, alarm. What these findings have not elicited has been a consistent response within the United States federal environmental-health establishment. Within that establishment are leading and subsidiary units. The Environmental Protection Agency (EPA) monitors environmental quality, enforces standards in accordance with statutes and rulings, regulates pesticides, maintains inventories of chemicals and toxic releases, and conducts laboratory testing, scientific research, and environmental education. The National Institute of Environmental Health Sciences (NIEHS) conducts and funds research probing the human health effects of environmental exposures; its Superfund Research Program (SRP) studies contaminated sites and their remediation, and its National Toxicology Program (NTP) develops analytical innovations and maintains a registry of carcinogens. The Centers for Disease Control and Prevention (CDC) includes two environmentally oriented subsidiaries: the Agency for Toxic Substances and Disease Registry (ATSDR), an advisory and non-regulatory unit focused on hazardous waste, and the National Center for Environmental Health (NCEH), whose core commitment is to protect from certain environmental hazards the public’s vulnerable subpopulations: the young, the old, and the disabled  but not As late as December 2016, the EPA, bearing primary federal environmental regulatory responsibility, had not developed a coherent strategy to mitigate mixture toxicity and cumulative risk, to alert the public to their plausibility, or to advise leadership in government and industry about their ramifications. Then, a month later, with the inauguration of a new president, environmental regulation itself became the first focus of an intensive effort to loosen restrictions on industrial and commercial activities, an effort, in sum, to accept more risks and reduce fewer . We haveDuring this period, 1980–2016, when initiatives might have advanced, stasis prevailed, even as an empirical premise for action had been converging, as sampled here, from three different directions: field study, epidemiological study, and experimental study.Field study had found abnormal development, including intersex anatomy, physiology, and behavior, among aquatic animals and their predators in watersheds subject to point-source  and non-Epidemiological study had found differential risk for urogenital abnormalities in children of countries similar in most respects but hosting dissimilar dominant industries , 15, andExperimental study had often found disturbing effects. Mixtures of homologous oil shale components had proved additively toxic to marine bacteria, but mixtures of non-homologous components, even of structural isomers, had proved synergistically toxic . Many enWhy, with much known, was little done? This question, to our knowledge, has not previously been posed across disciplines and decades. Its answer should help explain how scientific understanding and regulatory response diverged and how their divergence may yet be narrowed.We accessed holdings of the National Archives and Records Administration to examine documents, published and unpublished, deposited by or relating to the EPA and allied bodies from 1980 to 1986, the period when mixtures policy was forming and mixtures guidelines were being written. We analyzed the development, provisions, and consequences of six federal statutes enacted from 1972 through 2016, one Supreme Court ruling from 1980, and one presidential Executive Order from 1994. To study the legislative history of the Food Quality Protection Act, the federal statute that in 1996 introduced cumulative-risk and aggregate-risk obligations, we accessed United States Senate archives; complementary House of Representatives archives remained under embargo. We inspected one herbicide manufacturer’s internal communications released fortuitously through court order. We reviewed policy statements and framework documents and seven National Research Council advisory studies and assessed their influence. We searched PubMed.gov for “environmental mixture toxicity”, “cumulative risk”, “environmental justice”, and numerous narrower associated terms, concentrating on the 1980–2016 period and examining scientific evidence, topical reviews, and expert commentaries that either motivated or illuminated the policy history being probed. We did not conduct a systematic review of these literatures, nor did we conduct a meta-analysis. To supplement objective findings, and in a manner compliant with requirements of our Institutional Review Board, we interviewed four topic experts, three of them participants in the development and implementation of the policies investigated. The authors throughout collaborated to identify and pursue emergent themes.We present our findings narratively over time, tracing statutory, judicial, methodological, political, scientific, and regulatory factors as they came to prominence and as they interacted. Interviews are placed where most pertinent.Scientific interest in mixture toxicity had increased enough by 1952 to warrant comprehensive review and theoretical specification, with interactions — synergism and antagonism — modeled mathematically and cumulative risk promoted presciently as a topic for future study . Yet polThe EPA, formed 2 December 1970, focused initially on pollution at its sources: stack emissions, industrial and municipal effluents, pesticides applied to crops, and chemicals spilled onto land or into water. Immediate problems were not subtle, and “risk” was rarely mentioned. As multiple low-dose exposures to unfamiliar and poorly characterized chemicals became appreciated as commonplace, a new concept, “risk assessment”, took shape . EPA’s cThe EPA soon had additional responsibilities and, regarding chemical formulations, peculiar constraints. The Federal Insecticide Act of 1910 had been amended as the Federal Insecticide, Fungicide, and Rodenticide Act of 1947 (FIFRA) , essentiIn the new FIFRA, foundational definitions appeared. “Active ingredient … in the case of a pesticide” was defined as “an ingredient which will prevent, destroy, repel, or mitigate any pest”. “Inert ingredient” was defined as “an ingredient which is not active”. And “pesticide” itself was defined as “(1) any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest, and (2) any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant”. A pesticide, then, even if a mixture of ingredients “active” and “inert”, was, for regulatory purposes, unitary, and in this respect the EPA’s purview was to be “any pesticide if it contains any new active ingredient or if it would entail a changed use pattern” .Then, in 1976, the Toxic Substances Control Act  , enteredTSCA went on, still in Sect. 3, to define “mixture” tortuously and, one may suspect, tendentiously:(8) The term “mixture” means any combination of two or more chemical substances if the combination does not occur in nature and is not, in whole or in part, the result of a chemical reaction; except that such term [“mixture”] does include any combination which occurs, in whole or in part, as a result of a chemical reaction if none of the chemical substances comprising the combination is a new chemical substance and if the combination could have been manufactured for commercial purposes without a chemical reaction at the time the chemical substances comprising the combination were combined.(9) The term “new chemical substance” means any chemical substance which is not included in the chemical substance list compiled and published under Sect. 8 (b) .Untwisting these passages suggests their authors’ intent. No mixture could “occur in nature”, so at least one of any mixture’s chemical components had to be an industrial substance. No component could be “the result of a chemical reaction” without meeting two requirements. The “result” could not be “a new chemical substance”, a term paragraph (9), above, would define as a chemical not officially listed, and “the combination” had to be one that “could have been manufactured for commercial purposes without a chemical reaction”. So, really, all components had to be industrial substances, and that conclusion may tell why no guidance explained how two or more industrial substances could be declared a mixture when found among myriad natural substances; no guidance was needed. An environmental mixture could not be, in TSCA terms, a “mixture” if its components included chemical substances altered in the environment. Nor could the still toxic breakdown products of two different industrial substances constitute a mixture.These paragraphs, shrewdly crafted, could not have made environmental sense to drafters and legislators and regulators but would have made sense of other sorts. Polluters’ liability risks would have been easier to foresee, and to avoid, with mixtures defined restrictively. And the EPA’s responsibility to study real mixtures in real environments would have been diminished.Might statutory intent still be honored if mixtures were studied in laboratories? Yes. TSCA expressly required the testing of a mixture per se when prior knowledge of its individual components seemed a poor guide to understanding: “If the Administrator finds that … in the case of mixtures, the effects … on health or the environment may not be reasonably and more efficiently determined or predicted by testing the chemical substances which comprise the mixture the Administrator shall by rule require that testing be conducted” . To the Industrial Union Department, AFL-CIO v. American Petroleum Institute — that toxicant-specific quantitative risk assessment was necessary to justify regulatory intervention at any particular exposure level  data require careful interpretation. Even if these problems are solved satisfactorily, the preponderance of chemicals in the environment has not been studied with epidemiologic methods, and we would not wish to release newly produced substances only to discover years later that they were powerful carcinogenic agents. These limitations require reliance on less direct evidence that a health hazard exists [sic] human exposures. For example, exposure to cigarette smoke and asbestos gives an incidence of cancer that is much greater than anticipated from carcinogenicity data on each substance individually. Because data detecting such synergistic effects are often unavailable, they are often ignored or accounted for by the use of various safety factors  [[T]he latent period between exposure and disease is long, and exposures are mixed and multiple. Thus, epidemiologic  .Parenthetically, cigarette smoke, mentioned above, was not an individual substance but was already known to be a mixture of toxicants , even a science: it needed to know. And at this juncture it knew that linear regulatory policy was about to meet non-linear unregulated nature — polluted nature — and would have to adapt.Within a year, though, mixture-related apprehensions would cease to be subliminal. Whatever statutes required regulatory science could fulfill. Whatever statutes and the Supreme Court forbade regulatory science could avoid. But regulatory science was Thousands of hazardous waste sites, known generically as “Superfund sites”, had been contaminated with multiple chemicals and required risk prioritization to account for mixtures. Chemical-by-chemical risk assessment, environmental toxicology’s standard deliverable, had to be rethought . In Janunth; any combination assessed for cumulative risk would be arbitrarily small. Most glaringly when the subject was mixtures, addition’s limitations led the Agency Working Group to ignore interaction, whether potentiation or synergism or antagonism. In the end, the Agency Working Group chose to dismiss interaction not as a possibility but as a topic:Few toxicants had ever been evaluated in pairs, fewer still, if any, in complex mixtures. Would addition — adding the doses of sufficiently similar chemicals or somehow adding their effects — be good enough? Not generally; a simplifying restriction to similars would make addition practically useless in many environmental field-work settings. And as evident pharmacologically, small differences between similar molecules could generate markedly dissimilar effects; for instance, folic acid, taken as a vitamin, and methotrexate, taken as an anti-cancer drug, were almost identical — so similar that enzymes requiring the former were competitively inhibited by the latter . MathemaPrevious drafts of the document contained a lengthy discussion of the biological and chemical bases of toxicant interactions. The Agency Working Group felt that the discussion detracted from, rather than added to the clarity of the document, and this section was deleted. The literature cited in the document provides a detailed discussion of this issue for the interested reader .The Agency Working Group conceded that a two-component “mixture of concern”, if well enough characterized, might be considered a single compound, as if it were an ordinary toxicant or carcinogen evaluated for subchronic or chronic effects; dose-additive equations could be modified and interaction could be built in rather than modeled . Not recWith the interactions discussion deleted, with simple assumptions modeling complex realities, and with no answer for most cases, the document went out for external peer review. Misgivings were many and criticisms sharp.Most problematic for the Agency Working Group were the comments of Ellen Silbergeld, PhD, an environmental engineer and, at the time, Chief Toxics Scientist at the Environmental Defense Fund. “You will note that these comments are not supportive”, she wrote, 23 August 1984, and then in pen added a marginal comment: “I consider them unrealistic, since their explicit limitations make them difficult to apply in most situations facing the EPA”. What she had read was a plan not to grasp an exponential reality but to patch a linear algorithm.She continued:sic] which require assessment  It is clearly stated … that synergism (interactions other than additive) will not be considered in these guidelines. There is little justification for this policy decision, to reject any incorporation of models of other than additive interactions among toxicants. … [I]f interactions can be demonstrated, then equations other than those built around additivity must (rather than may) be used. The further discussion of possible (undemonstrated) interferences yielding less than additivity is suggested [disingenuously] to discount this obligation [to model synergism]. This is consistent with the whole thrust of this document is to exclude quantification other than additivity. … [This is] unacceptable[.] … In my opinion, most toxicant interactions occur because two or more chemicals affect the same organ system, through action at different receptor sites or cellular targets. … [This document is] scientifically unsubstantiated … [and based upon a] pathetically incomplete database … [and is] severely limited … [by too] many unhelpful comments. … It is commendable that the document admits that the assumptions underlying dose additivity “will not hold true in most cases”. However, no guidance is given to deal with these (majority) of cases. … [This is] a remarkably inflexible statement … [I am v]ery critical of the mathematical models … [which are based on] a simplistic assumption that because two compounds may antagonize each other at one site of action, they have no other affects hat’s what they told me a few minutes ago. … If we say we think it’s adequate with modifications and should be used, that would keep them in business”  at how limited toxicology is, and I got that from really understanding systematic methods. And systematic methods are basically a form of critical thinking which has never really been applied in toxicology”. Recently she had second-authored a critical review of toxicology, comparing it unfavorably to evidence-based medicine . That saShe did not wish to consider the environmental interaction of many thousands of industrial chemicals, calling that image “a googolplex”, googol being 10 raised to the 100th power. She preferred to consider a much smaller number of intensively produced chemicals but was still resistant to considering their interaction, since no regulatory response was conceivable.dissimilar sorts, even incompatible sorts, cumulative risks did not prompt the additive toxicological procedures applied to chemical mixtures — whose regulation, she insisted, current law in the United States, and in other countries, too, simply would not allow. “To regulate mixtures, the law must be changed”.The EPA’s initiatives under a cumulative-risk-assessment heading were less constrained than under a mixture-toxicity heading because “cumulative” risks, all of dissimilar sorts, were not “accumulated” risks, all of similar sorts. Being all of Why had EPA and other responsible agencies not tried to educate the public about mixture toxicity and its putative implications? Because they could not do that, nor could they lobby Congress. They could not initiate contact in order to educate or persuade. They could only try to wrangle an invitation to testify at a hearing or in some other way inform Congressional staffers.Are we looking through the wrong end of the telescope? Was regulatory futility not so much the challenge as it was the message? Rather than obsessing about individual chemicals analyzed outside their commercial formulations or environmental contexts, should we instead start planning a long careful transition to closed-loop — or zero-toxicant-emission — industrial practices? Yes, with inside-the-plant safety first assured, probably.Community health advocates in the 1980s had begun urging the EPA and state environmental agencies to address toxicants’ cumulative effects on disadvantaged populations. Some advocates became activists, first charging “environmental racism”, then demanding “environmental justice”, and eventually reconceptualizing risk assessment –104. TheThe federal government was not deaf to these concerns. From Congress in 1988 came a request to the National Academy of Sciences to characterize whatever risks might be posed by pesticide residues consumed in early life. In 1992, President George H. W. Bush established the Office of Environmental Justice in the EPA. In 1993, the National Environmental Justice Advisory Council (NEJAC) began operating as a formal advisory committee chartered to advise the EPA administrator .Pesticides in the Diets of Infants and Children, its writing committee chaired by a pediatrician-toxicologist, Philip J. Landrigan, MD, MSc, Mount Sinai School of Medicine, New York City , whenever practicable and appropriate, shall identify multiple and cumulative exposures” . Also inombined” .In August 1996 came two new statutes assigned for administration to the EPA, the first one suspect in origin and equivocal in effect.de minimis, enforcement of two provisions of the Food Additives Amendment of 1958, which had strengthened the Federal Food, Drug, and Cosmetic Act of 1938. The provisions — which became famous jointly as the “Delaney Clause”, after their author, Congressman James Delaney of New York — were these:Back in 1993, the Natural Resources Defense Council, the NRDC, through successful litigation, had forced the EPA to end its lax, or Provided, That no additive shall be deemed to be safe if it is found to induce cancer when ingested by man or animal, or if it is found, after tests which are appropriate for the evaluation of the safety of food additives, to induce cancer in man or animal; or“(A) fails to establish that the proposed use of the food additive, under the conditions of use to be specified in the regulation, will be safe: “(B) shows that the proposed use of the additive would promote deception of the consumer in violation of this Act or would otherwise result in adulteration or in misbranding of food within the meaning of this Act .“(3) No such regulation [prescribing safe use] shall issue if a fair evaluation of the data before the Secretary —Since the term “food additive” had been defined to include “a pesticide chemical”, strict enforcement of the Delaney Clause made legislative relief a priority for the pesticide industry, which lobbied vigorously for what would become the Food Quality Protection Act of 1996, the FQPA.Pesticides in the Diets of Infants and Children, but on 22 May 1996 Dr. Landrigan himself opposed the bill as then written, noting that it required the recommendations of his report to be implemented but then violated its own requirement, in part by removing pesticides from scrutiny under the Delaney Clause. Dr. Landrigan, testifying about the bill’s Senate version, went on to castigate a provision allowing:A more presentable prompt for the FQPA had been that a pesticide standard need not be health based if the imposition of a health-based standard would make unavailable a pesticide that is needed to maintain a particular food crop, “taking into account national and regional effects”. This small paragraph is a classic example of an exemption that eats a rule. … Mr. Chairman, as a pediatrician, I find this position unacceptable. … The incidence of cancer in America’s children is increasing. … With all due respect, I submit that S. 1166 is bad legislation. … I urge you not to enact this legislation  Administrator shall conduct biomedical studies to … develop new approaches to the study of complex mixtures, such as mixtures found in drinking water, especially to determine the prospects for synergistic or antagonistic interactions that may affect the shape of the dose–response relationship of the individual chemicals and microbes, and to examine noncancer endpoints and infectious diseases, and susceptible individuals and subpopulations”. Moreover, studies were to take “into account in the case of pesticides the time of application of the pesticide for the source water area and the travel time for the pesticide to reach such waters” .However discordant their mandates, these new laws brought complementary possibilities. One required that cumulative risk be assessed, and the other required that complex mixtures be taken seriously. The EPA, in the environmental-justice movement’s view, now had its orders: catch on and catch up.In 1997, the EPA administrator, Carol Browner, acknowledged that assessments had to account for combined effects. She announced that efforts were underway to develop methods for cumulative risk assessment and that these efforts would lead to new guidelines. But she also cautioned about stretching quantitative risk assessments to include social stressors: “While we can more consistently take into account many new factors in this approach to risk assessment, many other potentially important factors are more difficult to include in our analyses, particularly the social, economic, behavioral or psychological factors that also may contribute to adverse health effects. … Assessment of these factors is often hampered by a lack of data to establish plausible cause-and-effect relationships; difficulties in measuring exposure, incidence and susceptibilities related to these risks; and few methods for assessing or managing these risks. This guidance does not address these factors” . The tenGuidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a Common Mechanism of Toxicity. The EPA had not caught on, explaining that “[a] cumulative risk assessment begins with the identification of a group of chemicals, a common mechanism group (CMG), that induce a common toxic effect by a common mechanism of toxicity”  the field of risk assessment and to the Agency”. Paradoxically, though, the document acknowledged that cumulative-risk assessments were already being performed successfully in ecological settings and in “tribal cultures” and that “[t]he framework [for cumulative risk assessment] itself is conceptually similar to the approach used in both human health and ecological assessments, but it is distinctive in several areas”. Contrary to the NRC view, the Framework dismissed the terms “synergism” and “antagonism,” saying, “These terms are only marginally useful, in part because the underlying toxicologic concepts are only defined for two-chemical mixtures, and most environmental and occupational exposures are to mixtures of many more chemicals” lthough multiple methods are available, EPA has used only a few of them in practice. And despite recognition of nonchemical stressors as potentially important contributors to cumulative risk, nonchemical stressors are rarely addressed or evaluated”  while environmental justice (EJ) was being pushed out of CRA under a new director — ironically, since EJ had been the “CRA champion”.Had a risk-assessment methods emphasis, which had impeded risk-management action on mixtures toxicity and cumulative risk, co-opted scientific critics? Maybe. Were scientists taking refuge in methods refinement? No. Politicians were.Had CRA been designed to fail? No. Had CRA been designed to placate the EJ lobby? Yes. Had CRA been designed to occupy social scientists? No. Did CRA’s mechanistic diversity exculpate the chemical industry by diffusing liability into ambiguous interactions of chemical and nonchemical factors? Maybe.Regarding CRA and EJ, were CERCLA, and the EPA generally, limited by their enabling statutes? Maybe.While it did not change the definition of “mixture” or remove statutory constraints on the EPA’s ability to evaluate mixtures, the Frank R. Lautenberg Chemical Safety for the 21st Century Act of 2016  — a longAll that said, the Lautenberg Act did open a path to environmental justice, at least along a chemical-stressor cumulative-risk dimension. Aggregate exposures and “the likely duration, intensity, frequency, and number of exposures” were to be considered , and “poOther units of the federal environmental-health establishment took their own paths. Instructively contrasting were the attitudes of the ATSDR and the NIEHS.Framework for Assessing Health Impacts of Multiple Chemicals and Other Stressors (Update)  there always has been”. The agricultural-chemical industry exhibited a “dread of epidemiology”, which was “really the only science that addresses cumulative risk”, meaning that toxicology did not, “and was detecting risks — say, for non-Hodgkin’s lymphoma related to Roundup or glyphosate — that might be really an indication of true elevation of risk in workers that are exposed to a really complicated mixture [a declared active principal ingredient plus its “inactive” co-formulants] and have the other social factors and healthcare factors that put them at increased risk. … There was tangible anxiety about … really difficult regulatory implications. … I can tell you virtually every major issue I dealt with at EPA was a cumulative-risk issue. … I would have to say from a science perspective I felt very good that cumulative [risk] — not the social aspects of risk but from a chemical perspective — [was included in] the problem definition [of] almost every major issue. Now, frankly, that doesn’t mesh well with the regulatory mandates of the agency, so that makes it difficult because the regulatory mandates are very substance-specific, agent-specific. … The statutes [establishing the EPA’s regulatory mandates] are the antithesis of cumulative risk”.What would Dr. Burke do if political circumstances ever favored concerted action?He would overhaul TSCA, even as revised in 2016 by the Lautenberg Act. Senator Lautenberg died in office in 2013, and his namesake act was passed in a form equivocal with respect to mixtures and, more broadly, cumulative risk. And, in effect, it prohibited state-level leadership.Dr. Burke would shift safety’s “burden of proof” from the EPA to industry. He would rehabilitate the EPA’s original “best available technology” engineering mandate and deemphasize its “risk assessment” toxicology mandate, the latter dominant since 1983 but easily impeded legalistically. He would require “systems thinking”, such as he himself has facilitated by empaneling the Environmental Health Matters Initiative, the EHMI, within the National Academy of Sciences.Dr. Burke noted that public education has not heretofore been in the EPA’s mandate, but he thought it could be put there. “It  comes from the top [meaning the presidency] and [would require] a fully functioning science infrastructure [including the CDC] that has a strong public-health component to make it work”. Decisive action, such as a transition to closed-loop industrial production and non-production of egregious toxicants, “is way bigger than a regulatory agency”.The United States federal environmental-health establishment had already lost much of its ability to respond effectively to the harms studied here before it ever thought to do so.Congress had defined pesticide formulations, which were chemical mixtures, as single entities and had limited regulators’ examinations to only those ingredients declared to be “active”. It had defined any chemical mixture restrictively, excluding from study environmental mixtures reacting to form “new” chemical substances. And it had allowed any mixture to be assessed simply by characterizing, or referencing past characterizations of, its individual components, unless top management directed otherwise.The Supreme Court complicated matters for environmental regulators — but also simplified matters for them — by striking down OSHA’s inadequately explained requirement that polluters reduce their emissions to the lowest technologically feasible levels they could afford. Conscientious regulation of no-safe-dose toxicants became harder to envision than it would otherwise have been, when regulating toward zero was disallowed. For whatever reasons, the environmental-health establishment never did formulate a new standard that avoided OSHA’s past errors, despite what seemed a reasonable chance of success under review by a future court.These constraints, statutory and judicial, had come into place five months before Superfund was created. Recognizing an obligation to respond scientifically to the challenge presented by management of sites contaminated by complex mixtures, the EPA convened a group to consider mixture toxicity and write guidelines for assessment of risk. But the EPA had already grown accustomed to its constraints and showed little interest in escaping them, evidently because constraints were also now internal, even self-imposed. Efforts to write guidelines for evaluating mixture toxicity and later for evaluating cumulative risk displayed a fear that toxicology’s methods would be set adrift by requiring the assessment of multiple toxicants mixed in multiple ratios encountered in multiple exposures. Even if assessment were to venture beyond single chemicals, regulation seemed sure to be futile if any chemical’s safety were seen as contingent upon the presence or absence of some number of other chemicals in various amounts. Assessing and regulating chemicals one-by-one was hard enough; assessing and then regulating chemicals in mixtures promised to be exponentially harder, even impossible without reconceptualization of both regulatory mission and strategy.Embracing complexity would have required the EPA to sponsor research questioning its own practices and disquieting industries adapted to those practices. Yet one other unit, the NIEHS, did assertively commit itself to embracing complexity analytically and environmental justice more than rhetorically. Had it been encouraged to do so, the NIEHS might with programmatic research have begun to lay an evidentiary basis for fundamental regulatory reform.within the environment then toxicants must not be accepted into the environment. However facile it may seem initially, this deduction teaches — to industry, to agriculture, to a self-governing citizenry — an actionable lesson: minimize the exposome by, first, decelerating its expansion.Mixture toxicity and related issues presented to regulators an infinitude of interactions — Silbergeld’s “googolplex” — whose sorting, both scientifically and legally, was impossible. Yet impossibility was not the problem. Impossibility was the message, one we can still read, and with ever sharper acuity. If toxicants cannot be accepted Achieving even this much would require a salient intrusion into policy-as-usual and a robust commitment to end science-by-statute. Presidential and congressional cooperation would be needed and could be slow in coming. Agency-level initiatives could be more promising.We did confirm the importance of statutory constraint, but we also found statutory contrast and opportunity, most obviously in two bills enacted in 1996 and a third enacted in 2016. The Food Quality Protection Act required cumulative-risk assessment. The Safe Drinking Water Act Amendments required complex-mixture assessment with pesticides not excluded. And the Lautenberg Act required particular attention be paid to potentially exposed or susceptible subpopulations, opening a path to environmental-justice analytics and interventions. These three requirements, as supported by the persistent prodding of the National Research Council, could form a premise for action by a future, or by the current, EPA administrator. In parallel, the argument OSHA failed to make persuasively to the Supreme Court with respect to benzene in 1980 could be remade more broadly and with four decades of subsequent science to back it up; if so, then no-safe-dose toxicants could once again have their emissions driven toward zero, and low-dose exposures could come within the range of management.Regulatory science agencies and research science agencies are different, but they are not obliged to be as different as they have become. The most immediate need, we found, is for toxicologists to work with — not apart from and not in opposition to — epidemiologists, physiologists, endocrinologists, pathologists, and field biologists, all laboring to protect the environment from us and us from the environment.


William Abrão Saad was born on October 29, 1939, in the city of Araraquara, São Paulo, SP, Brazil. Their parents were Abrão Fadalala Saad and Carmen Habib Saad. He married Mrs. Ruth and had two children, William Abrão Saad Junior and Izabella Colane Barbosa SaadHe graduated from the Medical School of the University of São Paulo (FMUSP) Class of 1966. He specialized in surgery and devoted himself to a university career at the same educational institution where he graduated.He had as main research lines digestive surgery and liver transplantation; portal hypertension and liver regeneration. He obtained his PhD title in Surgery, in 1972 and his Full professor of Surgery at the Department of Gastroenterology, in 1975, both at FMUSP.He reached the position of Director of the Liver Surgery and Portal Hypertension Service at the Hospital das Clínicas of FMUSP, having pioneered the use of intraoperative ultrasound in this hospital, in addition to encouraging his team to implement the program for performing laparoscopic hepatectomies, a legacy that today puts the service under the leadership of Prof. Dr. Paulo Herman, as one of the great experiences of Latin America on the subject. He was a pioneer in the implementation of liver surgery in our midst in the most contemporary ways, and in addition he contributed a lot in the nineties with the strengthening of liver transplantation in our country.Among other functions that he performed, the following stand out: Chairman at the Faculty of Medical Sciences of Sorocaba of the Pontifical Catholic University of São Paulo; professor of surgery at the School of Medicine of the University of Santo Amaro (Unisa); and professor of surgical technical skills at the Faculty of Medicine of the University of City of São Paulo (Unicid). William Abrão Saad served on the editorial board of the following journals: Arquivos Brasileiros de Cirurgia Digestiva (ABCD); Arquivos Brasileiros de Cirurgia Digestiva (ABCD); Revista do Colégio Brasileiro de Cirurgiões; Acta Cirúrgica Brasileira; Revista da Faculdade de Ciências Médicas de Sorocaba and Arquivos de Gastroenterologia.He received dozens of awards during his career as a professor, being honored as a professor emeritus of Gastrão  in 2012 and in 2014 he was honored for having implemented liver surgery in the Hospital das Clínicas complex at FMUSP and, as a man integrated in the activities for the benefit of the society, he was recognized as Cidadão Paulistano (Honorary Citizen from São Paulo) in 2009 project of authorship of the councilman Antonio Carlos Rodrigues.William Abrão Saad was a member of the following entities: Brazilian College of Digestive Surgery and Asociaciones de Cirugia de Centro América y Panamá . He joined the São Paulo Academy of Medicine on April 2, 1982, rising to the status of an honorary member of this sodality. He was also honorary member of the Brazilian College of Surgeons.,He published 139 scientific articles in national and international journals; 55 abstracts in conference proceedings; more than 10 books, in addition to 60 chapters. He participated in 130 congresses and symposiums, having presented dozens of papers. He was a member of the organizing committee of six scientific eventsHe supervised nine master’s dissertations; three PhD theses and three other monographs. He produced 20 scientific videos. He participated in several examining boards, including 18 in public tenders; 27 master’s theses; two for doctoral qualifications; 17 doctorate; nine as a professor and eight as a full professor.It is observed that its scientific legacy is outstanding and its contributions to national surgery are unquestionable. However, more than that, we allow ourselves to remember Professor Saad, the “Saadão” (big Saad), as a friend, teacher and for his talent to identify young talents in a unique way. Always easy to deal with, friendly, patient and tolerant, he respected everyone around him, treating them like family members. His good-natured way, always attuned to everything around him, made him a memorable figure. Who was not approached by him at the end of a lecture with the simple request: “... son, son, I have to give a lecture in Sorocaba on this topic, can I get a copy of your presentation??? Hence my friends, you know ...” It was a real chase until he had the material in hand: he uses to send his private driver at doctor office to wait, phone calls, etc., most of the times he didn’t even use it ... And if you owed a meeting certificate for him? It was better to owe money for sure!His charisma and kindness allowed him to train dozens of disciples throughout Brazil. Many colleagues of national prominence in the hepatobiliopancreatic and transplant community were somehow supported by Professor Saad who was always ready to contribute to the Liver Surgery and Portal Hypertension Service at the FMUSP Hospital de Clínicas - where we can remember the professors Luiz Carneiro, Paulo Herman, Eleazar Chaib, doctors Vicenzo Pugliesi, Maria de Lourdes Capacci, Azzo Witman in São Paulo and in Sorocaba, professors Ronaldo Borghesi, José Mauro Rodrigues, Nelson Bocatto, Gisele Moreira, Angelo Zacariotto, Casio Rosas and Alvaro Gutierrez . In addition to these, other colleagues were at his side, such as me, Ben-Hur Ferraz Neto, Rogério Carballo Afonso, Osório Parra, Luigi Peduto, Adriano Pereira Sampaio, among many others.During 32 years of personal contact, one of the authors of this editorial (MAFR) mentions, among hundreds of stories he has to tell, the fact that Professor Saad never refused to support and stimulate him mainly regarding his career at the university in the professional level. He recalls several occasions when Professor Saad volunteered to help him in emergency operations in the middle of the night without making any question - “stick to every job” -, resistant and always willing to work, which, by the way, was the that moved and stimulated him. More than 1500 patients operated together. Everything was done with him: thyroidectomies, gynecological, breast, gastroenterological, oncological procedures ..., that is, an old school general surgeon, of those that are not done nowadays. He mentions MAFR that he learned a lot, and here he thanks you, in memorian! He also mentions that he can witness his charisma, affection and respect with patients and family, his simple and welcoming way that allowed him to create a strong clinic during all his 55 years of professional practice. In the last surgical procedure in January 2021 shared with Professor Saad at São Camilo Hospital in São Paulo, MAFR and his friend Adriano Sampaio noticed signs of tiredness and back pain in him, but ... nothing that a Novalgina (dipyrone) and a glass of water could not solve ... He did not stop!We will miss Professor Saad, his chats, his laughter at the operations and the lunches and dinners after them - which no one could ever try to pay -, from the messages on WhatsApp every day saying good morning and good night and sending “kisses …” , even of surprise cases, always more complex than they seemed and their simple way of facing challenges and obstacles.Professor Saad is physically gone, but his memory and legacy will be with us forever!See you soon Master!