A Phased Approach for Assessing Combined Effects from Multiple Stressors

We present a phased approach for evaluating the effects of physical, biological, chemical, and psychosocial stressors that may act in combination. Although a phased concept is common to many risk-based approaches, it has not been explicitly outlined for the assessment of combined effects of multiple stressors. The approach begins with the development of appropriate conceptual models and assessment end points. The approach then proceeds through a screening stage wherein stressors are evaluated with respect to their potential importance as contributors to risk. Stressors are considered individually or as a combination of independent factors with respect to one or more common assessment end points. As necessary, the approach then proceeds to consider interactions among stressors. We make a distinction between applications that begin with effects of concern (effects based) or with specific stressors (stressor based). We describe a number of tools for use within the phased approach. The methods profiled are ones that have been applied to yield results that can be communicated to a wide audience. The latter characteristic is considered especially important because multiple stressor problems usually involve exposures to communities or to ecologic regions with many stakeholders

Regulating under uncertainty : newsboy for exposure limits

Setting action levels or limits for health protection is complicated by uncertainty in the dose-response relation across a range of hazards and exposures. To address this issue, we consider the classic newsboy problem. The principles used to manage uncertainty for that case are applied to two stylized exposure examples, one for high dose and high dose rate radiation and the other for ammonia. Both incorporate expert judgment on uncertainty quantification in the dose-response relationship. The mathematical technique of probabilistic inversion also plays a key role. We propose a coupled approach, whereby scientists quantify the dose-response uncertainty using techniques such as structured expert judgment with performance weights and probabilistic inversion, and stakeholders quantify associated loss rates

Introduction

Roger M Cooke and Margaret MacDonell provide the introduction to this issu

Microplastics in the Great Lakes: Environmental, Health, and Socioeconomic Implications and Future Directions

Microplastics (MPs) are tiny pieces of plastic (<5 mm) that have been manufactured, shed from textiles, or formed as the degradation products of macroplastics. They can be taken up by aquatic organisms, leading to their incorporation into the food chain. Humans can consume MPs from fish as well as other impacted sources including bottled and tap water. MPs may pose risks to exposed organisms, and they can also act as vectors carrying additional adsorbed chemical pollutants and pathogens. MPs are an especially important focus regarding the Great Lakes because plastics comprise most of the litter, and the Great Lakes serve as a source of drinking water for 40 million people. This perspective summarizes the current state of MP pollution in the Great Lakes and potential risks posed to the environment, wildlife, and humans. A survey of detection, separation, and quantification methods is included. Potential remedies are explored, focusing on policy, human behavior, and the goal of a circular economy. Further research directions include standardizing detection and removal methods, assessing the health risk of MPs in the Great Lakes, and evaluating mitigation options

Example output from the relative risk model (RRM) illustrating combined stressor loadings ()

<p><b>Copyright information:</b></p><p>Taken from "A Phased Approach for Assessing Combined Effects from Multiple Stressors"</p><p></p><p>Environmental Health Perspectives 2007;115(5):807-816.</p><p>Published online 24 Jan 2007</p><p>PMCID:PMC1868003.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI</p

Assessing exposures and risks in heterogeneously contaminated areas: A simulation approach

The US Department of Energy (DOE) is responsible for cleanup activities at a number of facilities under its Environmental Restoration and Waste Management Program. The major goals of this program are to eliminate potential hazards to human health and the environment that are associated with contamination of these sites and, to the extent possible, make surplus real property available for other uses. The assessment of potential baseline health risks and ecological impacts associated with a contaminated site is an important component of the remedial investigation/feasibility study (RI/FS) process required at all Superfund sites. The purpose of this paper is to describe one phase of the baseline assessment, i.e., the characterization of human health risks associated with exposure to chemical contaminants in air and on interior building surfaces at a contaminated site. The model combines data on human activity patterns in a particular microenvironment within a building with contaminant concentrations in that microenvironment to calculate personal exposure profiles and risks within the building. The results of the building assessment are presented as probability distributions functions and cumulative distribution functions, which show the variability and uncertainty in the risk estimates. 23 refs., 2 figs., 1 tab