COMMENTARY Open AccessBrain matters: from environmental ethics toenvironmental neuroethicsLaura Y. Cabrera1,2*, Jordan Tesluk1,3, Michelle Chakraborti1, Ralph Matthews3 and Judy Illes1AbstractThe ways in which humans affect and are affected by their environments have been studied from many differentperspectives over the past decades. However, it was not until the 1970s that the discussion of the ethical relationshipbetween humankind and the environment formalized as an academic discipline with the emergence of environmentalethics. A few decades later, environmental health emerged as a discipline focused on the assessment and regulation ofenvironmental factors that affect living beings. Our goal here is to begin a discussion specifically about the impact ofmodern environmental change on biomedical and social understandings of brain and mental health, and to align thiswith ethical considerations. We refer to this focus as Environmental Neuroethics, offer a case study to illustrate keythemes and issues, and conclude by offering a five-tier framework as a starting point of analysis.Keywords: Brain health, Mental health, Environment, Ethics, Social implicationsBackground: At the crossroads of environment,brain and mental healthHumans have altered their environments in pursuit ofself-improvement and better opportunities since ancienttimes, but the scope and impact of these changes are un-precedented today [1]. Technological advancements haveyielded positive economic growth, improved standardsof living, and provided new ways of protecting humanhealth. At the same time, technology has contributed towidespread negative changes in the environment that in-clude global climate change, deforestation, suburbansprawl, ecosystem loss, and increased health risks fromexposure to radiation, toxicants, and stress.While there are different views among scholars of envir-onmental ethics about why humans should value the en-vironment [2], a common position focuses on direct andpotential consequences to human health and well-being[3]. Environmental health experts similarly focus on envir-onmental changes in terms of their impact on humanhealth. However, within approaches to environmentalethics and environmental health, less attention has beenpaid to the specific ethical, social and legal implications ofthese changes for brain and mental health.1 To do so, re-quires that we probe the intersection of diverse biological,social and cultural contexts of human well-being.Brain and mental health are determined by complex in-teractions between individual predispositions and behav-ior, social and economic processes, and the environment[4, 5]. Classic examples pointing to an association betweenneurological function and environmental changes includeneurological deficits from exposure to mercury [6] andlead [7–9], various forms of air [10–14] and water pollu-tion [15], pesticides, and solvents [16–20]. Moreover,cross-cultural studies of indigenous worldviews on iden-tity, concepts of the self, and wellness have highlighted thedirect and intimate connections between individuals andtheir environments [21, 22]. These studies remind us notonly about cross-cultural differences involved in experien-cing brain health and the environment, but also aboutdifferent layers of vulnerability [23] brought forward bythe impact of environmental change. Children [24], theelderly [25], workers who may be exposed occupationallyto neurotoxicants [20] and people who live in the proxim-ity of neurotoxicant sources [26] are more vulnerable thanother sectors of the population. These unequal levels ofexposure interacting with brain stage in development ordecline, and differential effects from environmental risks* Correspondence: Laura.cabrera@singularityu.org1National Core for Neuroethics, Division of Neurology, Department ofMedicine, University of British Columbia, 2211 Wesbrook Mall, Koerner S124,Vancouver, V6T 2B5 B.C., Canada2Center for Ethics & Humanities in the Life Sciences, Department ofTranslational Science and Molecular Medicine, Michigan State University, EastFee Hall, 965 Fee Road, Rm C211, East Lansing, MI 48823, USAFull list of author information is available at the end of the article© 2016 Cabrera et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Cabrera et al. Environmental Health (2016) 15:20 DOI 10.1186/s12940-016-0114-3are at the core of the environmental justice movementand, in regard to brain and mental health outcomes, are acentral concern of Environmental Neuroethics.Our goal here is to begin a discussion specificallyabout the impact of modern environmental change onbiomedical and social understandings of brain and men-tal health, and to align this with ethical considerations.There are several reasons for thinking that this approachis timely. To start, brain and mental health disorders,many of which have important environmental factors,are leading contributors to disabilities and morbiditythat produce critical public health, societal and eco-nomic impacts [27]. In addition, brain development, aswell as its optimal function throughout the life of indi-viduals, is particularly susceptible to the environment towhich a person is exposed [24]. Considering the vulner-ability of brains towards environmental exposures thatare not easy to identify or to eliminate [24], we can seewhy brain and mental health are matters of global con-cern and social justice and, in particular, as the healthrisks related to environmental exposures are often dis-tributed unequally. Thus, it becomes crucial to mitigatethe negative impacts of environmental change while en-suring fair distribution of the positive ones. This balancerepresents a key aspect of the Environmental Neu-roethics approach we present here.Fracking as a case studyFuel sources with low greenhouse gas emissions are fre-quently advanced as a replacement to the rapid expansionin fossil fuel usage [28]. Technological advancements suchas hydraulic fracturing (fracking) have now made extractionof these gas reserves profitable. The fracking process canimpact the environment in various ways through the ex-traction and discharge of massive quantities of contami-nated water, injection of various chemicals into the ground,and the disruption of the landscape with high densities ofroads and well-heads that encroach on human settlementsand wild habitats [29]. Like other literature on environmen-tal change, contamination of the air and water supplies inthe vicinity of fracking operations [17, 30] has been linkedto health impacts that include asthma, respiratory com-plaints, gastro-intestinal effects and nosebleeds [31, 32].Such contamination is also related to negative neurologicaleffects. For example, McKenzie and colleagues [26] carriedout a retrospective cohort study of 124,842 births between1996 and 2009 in rural Colorado examining the associa-tions between maternal proximity to fracking sites andbirth outcomes. They found that births to mothers residingclose to or surrounded by wells (>125 wells/mile) weretwice as likely to have a neural tube defects compared tothose with no wells within a 10-mile radius (OR = 2.0; 95 %CI: 1.0, 3.9, based on 59 cases).With these types of foundational studies in mind, we ex-amined the prevalence in the literature of associationsmade between fracking and neurological or mental healthimpacts. To this end, we carried out an extensive search ofpeer-reviewed and gray literature of articles, theses, books,abstracts, and government reports on unconventional gasdevelopment (UGD), environment, brain and mental healthusing Google Scholar, the most comprehensive databaserelevant to the goals of the study. The searches were basedon two primary key terms: (1) unconventional gas develop-ment, and (2) brain; key UGD search terms: {unconven-tional natural gas (+/−) development}, {shale gas (+/−)development}, {fracking} and {hydraulic fracturing}; and,key brain search terms were {brain}, {neuro}, {neurological}and {mental}. We also used a range of secondary searchterms to ensure that searches identify studies relevant toculture, First Nations, health, ethics, and solastalgia.2 Of theone hundred and six articles identified, 83 articles origi-nated from the peer-reviewed literature (reviews,N = 57; primary research N = 26) and 23 from the gray lit-erature, dating back to 2009 (Fig. 1).Fig. 1 Number of articles on fracking and brain by year (*up to September 2014)Cabrera et al. Environmental Health (2016) 15:20 Page 2 of 5To provide context, we explored the origin of thecases in our sample for country of corresponding authorand corresponding author disciplines. Most returns orig-inated from the United States (USA) (N = 83). Twelvepapers originated from Australia and six from Canada.One paper meeting our inclusion criteria originated eachfrom China, Germany, New Zealand, Switzerland andUnited Kingdom. Based on the corresponding authors’affiliation, we found that the majority of correspondingauthors held multiple disciplinary associations (N = 45).Twenty-two held affiliations in the health sciences (e.g.,medicine), 21 in the social sciences (e.g., sociology, law),11 were associated with environmental sciences, such asecology or forestry, and seven have disciplines repre-sented only in a limited basis such as engineering or re-gional planning.To explore the texts in depth, we conducted athree-part content analysis [33, 34] of the full set ofcases. Each individual article was used as the unit ofanalysis. In the first phase of the analysis, we foundthat the dominant themes relate to public health(N = 31), and regulation and policy (N = 22). Five arti-cles mention UGD and fracking broadly as a threat toIndigenous health.In a second phase, we focused on brain and mentalhealth. Eight of the 106 papers contain elaborate detailedexamination of the impact that UGD poses for brain andmental health, arguments for associations between brainand mental health related to UGD, or both. The remainingpapers only explore the relationship between frackingchemicals and neurotoxicity superficially and provide littleif any mention of ethical implications.In the third phase, we focused specifically on contentrelated to ethics. Two papers provide substantial ethicaldiscussion. One paper argues that environmental dam-age caused by hydraulic fracturing poses “a new threatto human rights” [35]. The other, written by members ofthe present author group, makes a call to the Presiden-tial Commission for the integration of ethical consider-ations and neuroscience into the study of environmentalchange [36]. Sixty-five papers mention safety and issuesrelated to the duty not to inflict harm; 41 papers men-tion at least one other ethical concern such as trust, vul-nerability, justice, and disempowerment but without anyfurther elaboration on the matter. Overall, the findingsreveal that while there is emphasis on health, there islimited ethical discussion of brain and mental healthimpacts.Environmental Neuroethics in the wildEnvironmental Neuroethics can provide a framework toinvestigate the ethical and social implications of environ-mental change on brain and mental health. Building onprevious work [37], we propose a five-tier framework:1. Brain science and the environment: Neurosciencediscovery that is aligned with the measurement andevaluation of factors that affect the way individuals,communities and society adapt and cope with realor perceived environmental threats to well-being.2. The relational self and the environment: Theinterface between the environment and brain andmental health, and the mechanisms by whichexposures at key points in life may mediate differentbrain and mental effects; relationships amongmental health stressors, susceptibility to mentalhealth issues, and resilience within the context ofchanging environments.3. Cross-cultural factors and the environment:Exploration of the role of culture in the relationshipbetween environment and brain and mental health;interactions between Traditional EcologicalKnowledge and neuroscience evidence; the impact ofenvironmental change and varying effects on FirstNations and settler communities given respectiverelationships between culture and the environment.4. Social policy and the environment: Priorities andallocation of resources of local social organizationsto deal with environmental impacts on brain andmental health.5. Public discourse and the environment: Theengagement of professional disciplines andcommunities in multidirectional communicationand discourse about neurological, psychological,sociological and ethical dimensions ofenvironmental change; facilitation of international,cross-disciplinary, transdisciplinary collaborations;creation of effective outreach programs thatpromote public understanding about the impact ofenvironmental change on brain and mental health.This framework can be extended more broadly toother environmental impacts such as the extraction ofnatural resources, air pollution, use of agricultural che-micals, water contamination, proximity to noxious facil-ities, mining waste and nuclear plants, oceandegradation, food contamination, and habitat destruc-tion. Moreover, while the focus here has been onchanges to the physical environment, EnvironmentalNeuroethics is also concerned with other environmentssuch as digital and social environments, and how theseimpact neurological health.Notwithstanding the opportunity to expand ethical andsocial discussion around environmental change, prioritysetting and paths to action are not without challenges. Re-liability and stability of evidence [38], knowledge of im-pacts [39], and appreciation of risk [40–42] are perceivedand weighted differently by different stakeholders and areamong the key obstacles.Cabrera et al. Environmental Health (2016) 15:20 Page 3 of 5ConclusionsThe identified gaps in the ethical discussion related toenvironmental change and health as well as the vulner-ability of brains, suggest that it is time for an Environ-mental Neuroethics dedicated to address the interactionof biomedical and social understandings of anthropo-genic environmental change. In moving forward, resultsand resulting scholarship and guidance must be specific,solution-oriented, and proportionate to the benefits andrisks in play.Endnotes1We use the term mental health to include “well-being, everyday problems in living associated with bodilysymptoms of stress and anxiety, mild depression, andseasonal fluctuations in mood and energy, as well asmore severe psychiatric disorders, such as major depres-sion, bipolar disorder, schizophrenia, and other psychoticdisorders” [21 xiv].2A term used to refer to distress cause by environmen-tal change.Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsLC participated in the design of the study, carried out analysis of data anddrafted the manuscript. MC gathered the data and helped with the analysis.JT, RM participated in the design of the study and interpretation of data. JIconceived the study, participated in its design and coordination, and helpedto draft the manuscript. All authors read and approved the final manuscript.AcknowledgmentsWe would like to acknowledge the support of CIHR (MOP-111240), the NorthGrowth Foundation, and the Canada Research Chairs Program. This work wasfurther enabled by support from the British Columbia Knowledge DevelopmentFund, the Canadian Foundation for Innovation and the Vancouver CoastalHealth Research Institute.Author details1National Core for Neuroethics, Division of Neurology, Department ofMedicine, University of British Columbia, 2211 Wesbrook Mall, Koerner S124,Vancouver, V6T 2B5 B.C., Canada. 2Center for Ethics & Humanities in the LifeSciences, Department of Translational Science and Molecular Medicine,Michigan State University, East Fee Hall, 965 Fee Road, Rm C211, EastLansing, MI 48823, USA. 3Department of Sociology, University of BritishColumbia, Vancouver, B.C., Canada.Received: 7 September 2015 Accepted: 4 February 2016References1. Watts N, Maiero M, Olson S, Hales J, Miller C, Campbell K, et al. 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