Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs)

Managing the provision of safe drinking water has a renewed focus in light of the new World Health Organization (WHO) water safety plans. Risk analysis is a necessary component to assist in selecting priority hazards and identifying hazardous scenarios, be they qualitative to quantitative assessments. For any approach, acute diarrhoeal pathogens are often the higher risk issue for municipal water supplies, no matter how health burden is assessed. Furthermore, potential sequellae (myocarditis, diabetes, reactive arthritis and cancers) only further increase the potential health burden of pathogens; despite the enormous uncertainties in determining pathogen exposures and chemical dose-responses within respective microbial and chemical analyses. These interpretations are currently being improved by Bayesian and bootstrapping approaches to estimate parameters for stochastic assessments. A case example, covering the health benefits of ozonation for Cryptosporidium inactivation versus potential cancers from bromate exposures, illustrated the higher risks from a pathogen than one of the most likely disinfection by-products (DBPs). Such analyses help justify the industries long-held view of the benefits of multiple barriers to hazards and that microbial contamination of water supplies pose a clear public health risk when treatment is inadequate. Therefore, efforts to reduce potential health risks from DBP must not compromise pathogen control, despite socio-political issues.     

Characterization of Risks Posed by Combustor Emissions

ABSTRACT

Risk characterization is the final step of the risk assessment process as practiced in the U.S. EPA. In risk characterization, the major scientific evidence and “bottom-line” results from the other components of the risk assessment process, hazard identification, dose-respdnse assessment, and exposure assessment, are evaluated and integrated into an overall conclusion about the risks posed by a given situation. Risk characterization is also an iterative process; the results of a specific step may require re-evaluation or additional information to finalize the risk assessment process. Risks posed by atmospheric emissions are an example of an involuntary human health risk which typically receives a great deal of public attention. Characterization of the risks posed by atmospheric emissions typically requires the use of mathematical models to evaluate: I) the environmental fate of emitted pollutants, 2) exposures to these pollutants, and 3) human dose-response. Integration df these models results in quantitdtive risk estimates. The confidence in a quantitative risk estimate is examined by evaluating uncertainty and variability within individual risk assessment components. Variability arises from the true heterogeneity in characteristics within a population or an event; on the other hand, uncertainty represents lack of knowledge about the true value used in a risk estimate. U.S. EPA's 1997 Mercury Study will illustrate some aspects of the risk characterization process as well as the uncertainty and variability encountered in the risk assessment process.     

Risk management : a European regulatory perspective.

Risk management for European regulators means the detection and assessment of risks, the development and selection of measures to reduce risk, and monitoring of the effectiveness of risk control; all aspects of pharmacovigilance intended to minimise risk to European Union citizens associated with use of medicinal substances. This incorporates earlier and better planning of pharmacovigilance through formal product risk-management plans, better use of information tools to protect public health and routine audit of effectiveness of regulatory action.     

Calculation of human health risk-based screening levels (RBSLs) for petroleum

Hazardous waste site managers and regulators can decide easily whether site contamination requires remediation to protect human health, but defining the extent of cleanup is often an enormous challenge. When is the site clean enough for human access and use? Risk assessment tools can be used to help answer this question. One can calculate chemical-specific risk-based screening levels (RBSLs) in environmental media (e.g. soil, water, and food) that correspond to "acceptable" levels of risk. RBSLs can be calculated for individual chemicals and chemical mixtures, specific to various exposure pathways. In calculating RBSLs, one must account for the fact that people may be exposed to more than one chemical by more than one exposure pathway. Fate and transport models may be needed to predict how people might become exposed to site contamination in the future. Examples RBSLs for non-cancer effects are calculated to illustrate the utility and limitations of RBSLs for making risk-based decisions at petroleum release sites.     

Impact of messages about scientific uncertainty on risk perceptions and intentions to use electronic vaping products

BackgroundThe science surrounding e-cigarettes and other electronic vaping products (EVPs) is rapidly evolving, and the health effects of vaping are unclear. Little research has explored how individuals respond to information acknowledging scientific uncertainty. The aim of the present study was to understand the impact of messages about scientific uncertainty regarding the health effects of vaping on risk perceptions and behavioral intentions.MethodsAdults in an online experiment (n = 2508) were randomly exposed to view either a control message (a short factual statement about EVPs) or an uncertainty message (the control message plus additional information describing why EVP-related research is limited or inconclusive). Participants rated the risks of vaping and their intentions to try or stop vaping.ResultsIndividuals who viewed the uncertainty message rated vaping as less risky than those who viewed the control message. Message exposure did not impact intentions to try vaping soon or intentions to stop vaping in the next 6 months.ConclusionsAcknowledging scientific uncertainty made EVP use seem less risky. Future research should explore possible drivers of this response, such as deeper message processing or emotional reactions. Researchers and practitioners designing public health campaigns about vaping might consider a cautious approach to presenting information about scientific uncertainty.     

Pathways between COVID-19 public health responses and increasing overdose risks: A rapid review and conceptual framework

BackgroundEmerging evidence indicates that illicit drug overdoses are increasing throughout the COVID-19 pandemic. There is a paucity of evidence on the causative pathways for this trend, but expert opinions, commentaries, and some reviews offer theoretical underpinnings.MethodsIn this rapid review, we collate the available published evidence, expert opinions, commentaries, and reviews on the unintended pathways between COVID-19 public health responses and increasing illicit drug overdoses. Using tenets of thematic analyses and grounded theory, we also offer a visual conceptual framework for these unintended pathways.ResultsOur framework focuses on five particular public health responses, namely social isolation/physical distancing/quarantine; staff/resource reallocations and reductions; closures of businesses and other places of employment; border closures and transportation restrictions; and the early release of people from prisons. As argued in the literature reviewed here, these public health responses have unintentionally created increased overdose risks by producing high risk use scenarios; increased risks of relapsing; disrupted addictions services and treatment; an increasingly toxic supply of drugs; and the risk of using with lowered tolerance.ConclusionsHealth care systems should respond to these pathways to mitigate the unintended consequences. Furthermore, the COVID-19 pandemic may represent an opportunity to enact proactive, progressive, and innovative solutions to an overdose crisis that will surely outlast the current pandemic.     

Comparative risk assessment and cessation information seeking among smokeless tobacco users

IntroductionThis research examined (1) smokeless tobacco users' comparative optimism in assessing the health and addiction risks of their own product in comparison with cigarettes, and (2) the effects of comparative optimism on cessation information-seeking.MethodsA nationally-representative sample from the 2015 Health Information National Trends Survey (HINTS)-FDA was employed.ResultsThe analyses revealed the presence of comparative optimism in assessing both health and addiction risks among smokeless tobacco users. Comparative optimism was negatively correlated with most cessation information-seeking variables. Health bias (the health risk rating gap between the subject's own tobacco product and cigarettes) was associated with decreased intent to use cessation support. However, the health bias and addiction bias (the addiction risk rating gap between the subject's own tobacco product and cigarettes) were not consistent predictors of all cessation information-seeking variables, when covariates of socio-demographics and tobacco use status were included. In addition, positive correlations between health bias and past/recent cessation-information searches were observed.ConclusionsOptimisic biases may negatively influence cessation behaviors not only directly but also indirectly by influencing an important moderator, cessation information-seeking. Future interventions should prioritize dispelling the comparative optimism in perceiving risks of smokeless tobacco use, as well as provide more reliable cessation information specific to smokeless tobacco users.     

The public and effective risk communication

Public perceptions of risk have often been dismissed on the basis of "irrationality", and have tended to be excluded from policy processes by risk assessors and managers. People's responses to different risks are determined by psychological factors. The technical risk estimates traditionally provided by experts do not influence people's behaviours and responses in the same way as their risk perceptions. Some concerns are very specific to particular hazard. It is also important to communicate the difference between probability and variability associated with risk estimates. Risk communication must take account of the actual concerns of the public (for example, potential for negative environmental impact, unintended human health effects, or vulnerable groups within the population). When the public want information about a risk, they prefer a clear message regarding risks and associated uncertainties, including the nature and extent of disagreements between different experts. Furthermore, societal priorities for risk mitigation activities may not align with those identified by expert groups. Dismissing the former as irrelevant may result increased distrust in the motives of regulators and industry, with consequences for public confidence in regulatory activities linked to public protection. Awareness and understanding of public concerns must be the basis of an effective risk management strategy.     

Conceptual site models as a tool in evaluating ecological health: the case of the Department of Energy's Amchitka Island nuclear test site

Managers of contaminated sites are faced with options ranging from monitoring natural attenuation to complete removal of contaminants to meet residential health standards. Conceptual site models (CSMs) are one tool used by the U.S. Department of Energy (DOE) and other environmental managers to understand, track, help with decisions, and communicate with the public about the risk from contamination. CSMs are simplified graphical representations of the sources, releases, transport and exposure pathways, and receptors, along with possible barriers to interdict pathways and reduce exposure. In this article, three CSMs are created using Amchitka Island, where the remaining contamination is from underground nuclear test shot cavities containing large quantities of numerous radionuclides in various physical and chemical forms: (1) a typical underground nuclear test shot CSM (modeled after other sites), (2) an expanded CSM with more complex receptors, and (3) a regional CSM that takes into account contaminant pathways from sources other than Amchitka. The objective was to expand the CSM used by DOE to be more responsive to different types of receptors. Amchitka Island differs from other DOE test shot sites because it is surrounded by a marine environment that is highly productive and has a high biodiversity, and the source of contamination is underground, not on the surface. The surrounding waters of the Bering Sea and North Pacific Ocean are heavily exploited by commercial fisheries and provide the United States and other countries with a significant proportion of its seafood. It is proposed that the CSMs on Amchitka Island should focus more on the pathways of exposure and critical receptors, rather than sources and blocks. Further, CSMs should be incorporated within a larger regional model because of the potentially rapid transport within ocean ecosystems. The large number of migratory or highly mobile species that pass by Amchitka provide the potential for a direct pathway to the local human population, known as Aleut, and commercial fisheries, which are remote from the island itself. The exposure matrix for receptors requires expansion for the Amchitka Island ecosystem because of the valuable marine and seafood resources in the region. CSMs with an expanded exposure/receptor matrix can be used effectively to clarify the conceptualization of the problem for scientists, regulators, and the general public.     

Characterization of risks posed by combustor emissions

Risk characterization is the final step of the risk assessment process as practiced in the U.S. EPA. In risk characterization, the major scientific evidence and "bottom-line" results from the other components of the risk assessment process, hazard identification, dose-response assessment, and exposure assessment, are evaluated and integrated into an overall conclusion about the risks posed by a given situation. Risk characterization is also an iterative process; the results of a specific step may require re-evaluation or additional information to finalize the risk assessment process. Risks posed by atmospheric emissions are an example of an involuntary human health risk which typically receives a great deal of public attention. Characterization of the risks posed by atmospheric emissions typically requires the use of mathematical models to evaluate: 1) the environmental fate of emitted pollutants, 2) exposures to these pollutants, and 3) human dose-response. Integration of these models results in quantitative risk estimates. The confidence in a quantitative risk estimate is examined by evaluating uncertainty and variability within individual risk assessment components. Variability arises from the true heterogeneity in characteristics within a population or an event; on the other hand, uncertainty represents lack of knowledge about the true value used in a risk estimate. U.S. EPA's 1997 Mercury Study will illustrate some aspects of the risk characterization process as well as the uncertainty and variability encountered in the risk assessment process.     

Research strategies for safety evaluation of nanomaterials, Part III: nanoscale technologies for assessing risk and improving public health.

Risk assessment in the environmental health sciences focuses on understanding the nature of environmental exposures and the potential harm posed by those exposures which in turn is determined by the perturbation of biological pathways and the individual's susceptibility to damage. While there are extensive research efforts ongoing in these areas, progress in each is currently slowed by technological limitations including comprehensive assessment of multiple exposures in real time and dynamic assessment of biological response with high temporal and quantitative resolution. This Forum article discusses recent technological innovations capitalizing on the emergent properties of nanoscale materials and their potential adaptation to improving individual exposure assessment, determination of biological response, and environmental remediation. The ultimate goal is to raise the environmental health science community's awareness of these possibilities and encourage the development of improved strategies for assessing risk and improving public health.     

Health Effects of Airborne Particulate Matter: Do We Know Enough to Consider Regulating Specific Particle Types or Sources?

Researchers and regulators have often considered preferentially regulating the types of ambient airborne particulate matter (PM) most relevant to human health effects. While few would argue the inherent merits of such a policy, many believe there may not yet be enough information to differentially regulate PM species. New evidence, using increasingly sophisticated methodologies, has become available in the last several years, allowing more accurate assessment of exposure and resultant associations with specific types of PM, or PM derived from different sources. Such new studies may also allow differentiation of effects from different chemical components in the same study against the same health endpoints. This article considers whether this new evidence might be adequate to allow us to “speciate” PM types or sources by severity of health effects. We address this issue with respect to two widespread sources of PM, emissions from motor vehicles and coal-fired power plants. Emissions from less widespread sources, residual oil and steel/coking facilities, are also discussed in order to illustrate how health effects associated with such emissions might instead be associated with more widespread sources when accurate exposure information is unavailable. Based upon evaluation of studies and methodologies which appear to contain the most accurate information on exposure and response to important emissions, including variable local emissions, it is concluded that public health will likely be better protected by reduction of various vehicular emissions than by continued regulation of the total mass of fine PM (PM <2.5 μ m, or PM_2.5) as if all PM in this mode is equitoxic. However, the knowledge base is incomplete. Important remaining research questions are identified.     

Cholinesterases in Aquatic Biomonitoring: Assay Optimization and Species-Specific Characterization for a California Native Fish

Cholinesterase (ChE) enzyme activity measurements are widely applied in aquatic organisms for water quality monitoring, especially for pesticide contamination in agricultural watersheds. These biomarkers are amenable to measurement in a variety of species, and are therefore useful for examining effects in model organisms relevant to the ecosystem of interest. However, extensive variation in ChE biochemistry exists among tissues and species. This variation is rarely characterized and may lead to biases in the interpretation of activity determinations. We optimized ChE activity measurement parameters and characterized ChE biochemistry in Sacramento sucker (Catostomus occidentalis), a widely distributed fish native to watersheds of the Central Valley of California. Acetylcholinesterase (AChE) was the predominant ChE present in C. occidentalis brain and muscle, and muscle AChE was most sensitive to diazinon inhibition. Field caging experiments indicated that exposures to ChE-inhibiting pesticides were insufficient to induce neurotoxic effects. However, pesticide usage in the Central Valley is highly variable among years, and long-term monitoring of in-stream effects would be necessary to evaluate trends in pesticide contamination. Recent changes to the State Water Code require agricultural landowners to participate in a regional water quality monitoring plan. As with most regional monitoring plans, measurements of in-stream effects, and effects in resident species, are not scheduled to be included. We suggest that inclusion of biomarker measures would lend important information to the monitoring process, and propose these procedures as a template for adapting ChE activity measurements into region-specific monitoring programs to assess in-stream effects of pesticide contamination on native species.     

A social media microinfluencer intervention to reduce coronavirus disease 2019 vaccine hesitancy in underserved Tennessee communities: A protocol paper

BackgroundCentral to effective public health policy and practice is the trust between the population served and the governmental body leading health efforts, but that trust has eroded in the years preceding the pandemic. Vaccine hesitancy among adults is also a growing concern across the United States. Recent data suggest that the trustworthiness of information about the coronavirus 2019 (COVID-19) vaccine was a larger concern than the vaccine’s adverse effects or risks.ObjectiveThis study aims to describe the methods used to create a public health microinfluencer social media vaccine confidence campaign for the COVID-19 vaccine in underserved Tennessee communities. A secondary objective is to describe how the Social-Ecological Model (SEM) and Social Cognitive Theory may address vaccine hesitancy using community pharmacies.MethodsIn late 2020, 50 independent community pharmacies in underserved communities across Tennessee were involved in a public health project with the State of Tennessee Department of Health and the University of Tennessee Health Science Center College of Pharmacy. The project involved a 3-pronged, pharmacy-based COVID-19 vaccination outreach project, including (1) social media messaging (i.e., microinfluencer approach), (2) community partner collaboration, and (3) in-pharmacy promotion. Quantitative and qualitative data will assess the quality and effectiveness of the program. Social media outcomes will also be assessed to measure the impact of the microinfluencer social media training.ResultsProject implementation is planned for 6 months (January 2021 to June 2021) after an initial month of planning by the research team (December 2020) and preceding several months of assessment (July 2021 and beyond).ConclusionsNovel, theory-based approaches will be necessary to improve vaccine confidence. One approach to promoting public health, derived from the SEM, may be to use trusted microinfluencers on social media platforms, such as local community pharmacists and community leaders.     

Intelligent risk communication: can it be improved?

Every year, regulators and scientists from academia and industry invest considerable time and effort into drug development, the assessment of safety, and subsequent risk-benefit communication. The observation of everyday medical practice, lay press releases and drug information indicates that all these efforts do not do justice to the work and effort invested. Risk communication is a complex scientific activity, which, when done properly, benefits patients, and when done poorly, may lead to harm. There is much misunderstanding and confusion even between professionals in communicating risk-benefit information, as the association of risk with drug treatment is a difficult concept to accept. It is apparent that the concept of intelligent risk-benefit communication has to be developed extensively on many levels and with the co-operation of everyone involved (patients, physicians, regulators, scientists, journalists, lawyers and the government). This article addresses some key aspects of dealing with the risks associated with drug treatment in everyday practice, as consideration of these risks may be of benefit to all concerned in the future.     

Proceedings of the Hydrogen Sulfide Health Research and Risk Assessment Symposium October 31-November 2, 2000

The Hydrogen Sulfide Health Research and Risk Assessment Symposium came about for several reasons: (1) increased interest by the U.S. Environmental Protection Agency (EPA) and several state agencies in regulating hydrogen sulfide (H2S); (2) uncertainty about ambient exposure to H2S; (3) confusion and disagreement in the literature about possible health effects at low-level exposures; and (4) presentation of results of a series of recent animal bioassays. The American Petroleum Institute (API) proposed this symposium and the EPA became an early co-sponsor, with the Chemical Industry Institute of Toxicology (CIIT) and the American Forest & Paper Association (AF&PA) contributing expertise and funding assistance. The topics covered in this symposium included Animal Research, Human Research, Mode-of-Action and Dosimetry Issues, Environmental Exposure and Monitoring, Assessment and Regulatory Issues, and closed with a panel discussion. The overall goals of the symposium were to: gather together experts in H2S health effects research and individuals from governmental agencies charged with protecting the public health, provide a venue for reporting of recent research findings, identify gaps in the current information, and outline new research directions and promote research collaboration. During the course of the symposium, presenters provided comprehensive reviews of the state of knowledge for each topic. Several new research proposals discussed at the symposium have subsequently been initiated. This report provides a summary of the talks, poster presentations, and panel discussions that occurred at the Hydrogen Sulfide Health and Risk Assessment Symposium.