Environmental risk assessors as honest brokers or stealth advocates.

Risk assessment ought to provide a solid, evidence base to risk management in the development of environmental policy and decisions, where the risk assessors act without advocacy as honest brokers of science advice. But there are concerns that the values of the risk assessors might undermine the objectivity of the process. For similar reasons, there is suspicion that more interaction between risk assessors and risk managers might contaminate the science. On the contrary, here the argument is that making risk assessment more management- and value-relevant, through more effective dialogue, provides a better foundation for objective science advice.

Macrocyclic fragrance materials--a screening-level environmental assessment using chemical categorization.

A screening-level aquatic environmental risk assessment for macrocyclic fragrance materials using a "group approach" is presented using data for 30 macrocyclic fragrance ingredients. In this group approach, conservative estimates of environmental exposure and ecotoxicological effects thresholds for compounds within two subgroups (15 macrocyclic ketones and 15 macrocyclic lactones/lactides) were used to estimate the aquatic ecological risk potential for these subgroups. It is reasonable to separate these fragrance materials into the two subgroups based on the likely metabolic pathway required for biodegradation and on expected different ecotoxicological modes of action. The current volumes of use for the macrocyclic ketones in both Europe and North America ranges from <1 (low kg quantities) to no greater than 50 metric tonnes in either region and for macrocyclic lactones/lactides the volume of use range for both regions is <1 to no greater than 1000 metric tonnes in any one region. Based on these regional tonnages, biodegradability of these two subgroups of materials, and minimal in stream dilution (3:1), the conservatively predicted exposure concentrations for macrocyclic ketones would range from <0.01 to 0.05 µg/L in Europe and from <0.01 to 0.03 µg/L in North America. For macrocyclic lactones/lactides, the concentration within the mixing zone would range from <0.01 to 0.7 µg/L in Europe and from <0.01 to 1.0 µg/L in North America. The PNECs derived for the macrocyclic ketones is 0.22 µg/L and for macrocyclic lactones/lactides is 2.7 µg/L. The results of this screening-level aquatic ecological risk assessment indicate that at their current tonnage, often referred to as volumes of use, macrocyclic fragrance materials in Europe and North America, pose a negligible risk to aquatic biota; with no PEC/PNEC ratio exceeding 1 for any material in any subgroup.

Environmentally sensitive life-cycle traits have low elasticity: implications for theory and practice.

The relationships between population growth rate and the life-cycle traits contributing to it are nonlinear and variable. This has made it difficult for ecologists to consistently predict changes in population dynamics from observations on changes in life-cycle traits. We show that traits having a high sensitivity to chemical toxicants tend to have a low elasticity, meaning that changes in them have a relatively low impact on population growth rate, compared to other life-cycle traits. This makes evolutionary sense in that there should be selection against variability in population growth rate. In particular, we found that fecundity was generally more sensitive to chemical stress than was juvenile or adult survival or time to first reproduction, whereas fecundity typically had a lower elasticity than the other life-cycle traits. Similar relationships have been recorded in field populations for a wide range of taxa, but the conclusions were necessarily more tentative because stochastic effects and confounding variables could not be excluded. Better knowledge of these relationships can be used to optimize population management and protection strategies and to increase understanding of the drivers of population dynamics.

The extrapolation problem and how population modeling can help.

We argue that population modeling can add value to ecological risk assessment by reducing uncertainty when extrapolating from ecotoxicological observations to relevant ecological effects. We review other methods of extrapolation, ranging from application factors to species sensitivity distributions to suborganismal (biomarker and "-omics") responses to quantitative structure-activity relationships and model ecosystems, drawing attention to the limitations of each. We suggest a simple classification of population models and critically examine each model in an extrapolation context. We conclude that population models have the potential for adding value to ecological risk assessment by incorporating better understanding of the links between individual responses and population size and structure and by incorporating greater levels of ecological complexity. A number of issues, however, need to be addressed before such models are likely to become more widely used. In a science context, these involve challenges in parameterization, questions about appropriate levels of complexity, issues concerning how specific or general the models need to be, and the extent to which interactions through competition and trophic relationships can be easily incorporated.

Identifying and assessing the application of ecosystem services approaches in environmental policies and decision making.

The presumption is that ecosystem services (ES) approaches provide a better basis for environmental decision making than do other approaches because they make explicit the connection between human well-being and ecosystem structures and processes. However, the existing literature does not provide a precise description of ES approaches for environmental policy and decision making, nor does it assess whether these applications will make a difference in terms of changing decisions and improving outcomes. We describe 3 criteria that can be used to identify whether and to what extent ES approaches are being applied: 1) connect impacts all the way from ecosystem changes to human well-being, 2) consider all relevant ES affected by the decision, and 3) consider and compare the changes in well-being of different stakeholders. As a demonstration, we then analyze retrospectively whether and how the criteria were met in different decision-making contexts. For this assessment, we have developed an analysis format that describes the type of policy, the relevant scales, the decisions or questions, the decision maker, and the underlying documents. This format includes a general judgment of how far the 3 ES criteria have been applied. It shows that the criteria can be applied to many different decision-making processes, ranging from the supranational to the local scale and to different parts of decision-making processes. In conclusion we suggest these criteria could be used for assessments of the extent to which ES approaches have been and should be applied, what benefits and challenges arise, and whether using ES approaches made a difference in the decision-making process, decisions made, or outcomes of those decisions. Results from such studies could inform future use and development of ES approaches, draw attention to where the greatest benefits and challenges are, and help to target integration of ES approaches into policies, where they can be most effective. Integr Environ Assess Manag 2017;13:41-51. © 2016 SETAC.

A framework for predicting impacts on ecosystem services from (sub)organismal responses to chemicals.

Protection of ecosystem services is increasingly emphasized as a risk-assessment goal, but there are wide gaps between current ecological risk-assessment endpoints and potential effects on services provided by ecosystems. The authors present a framework that links common ecotoxicological endpoints to chemical impacts on populations and communities and the ecosystem services that they provide. This framework builds on considerable advances in mechanistic effects models designed to span multiple levels of biological organization and account for various types of biological interactions and feedbacks. For illustration, the authors introduce 2 case studies that employ well-developed and validated mechanistic effects models: the inSTREAM individual-based model for fish populations and the AQUATOX ecosystem model. They also show how dynamic energy budget theory can provide a common currency for interpreting organism-level toxicity. They suggest that a framework based on mechanistic models that predict impacts on ecosystem services resulting from chemical exposure, combined with economic valuation, can provide a useful approach for informing environmental management. The authors highlight the potential benefits of using this framework as well as the challenges that will need to be addressed in future work. Environ Toxicol Chem 2017;36:845-859. © 2017 SETAC.

Energy allocation rules inDaphnia magna: clonal and age differences in the effects of food limitation.

The allocation of energy to carapace formation, respiration, growth, and reproduction were examined in two parthenogenetic clones ofDaphnia magna (Cladocera) cultured at two levels of food (Chlorella) concentration. Clonal differences in energy allocation were more apparent at high ration (1.5 µg C mL-1) than at low ration (0.3 µg C mL-1). These differences included respiratory and molting costs, and the timing of energy allocation to growth and reproduction. A comparison of active vs. anesthetized animals revealed that the interclonal difference in respiration rate was the result of a difference in activity level. In both clones mass-specific rates of respiration, growth, and brood production all decreased at low vs. high ration levels, whereas mass-specific molt-loss rate increased. Lowered food concentration decreased the relative allocation of energy to growth and reproduction, but increased allocation to maintenance (respiration and carapace formation). These allocation responses to food limitation indicated that for both clones the highest energy priority was carapace formation. However, the relative priority of respiration, growth and reproduction varied with age and clone. In juveniles (instars 1-4) the priority ranking of growth was essentially equal to that of respiration, whereas respiration always had higher priority in adults (instars 5-9). All three possibilities for the relative ranking of growth and reproduction (i.e., growth>reproduction, growth=reproduction, and reproduction>growth), as specified by different models in the literature, were observed depending on age and clone. The energy allocation rules were also shown to vary between other daphniid species. Furthermore, metabolic responses to chronic food limitation may be different from responses to acute food deprivation. In this study, one clone showed a greater decrease in respiration rate as a result of lifetime food limitation than did the other, but the opposite was true when these clones were exposed to 48 h of starvation. These differences in allocation rules and in acute vs. chronic responses may have to be considered when using physiological data to modelDaphnia populations.

Developing predictive systems models to address complexity and relevance for ecological risk assessment.

Ecological risk assessments (ERAs) are not used as well as they could be in risk management. Part of the problem is that they often lack ecological relevance; that is, they fail to grasp necessary ecological complexities. Adding realism and complexity can be difficult and costly. We argue that predictive systems models (PSMs) can provide a way of capturing complexity and ecological relevance cost-effectively. However, addressing complexity and ecological relevance is only part of the problem. Ecological risk assessments often fail to meet the needs of risk managers by not providing assessments that relate to protection goals and by expressing risk in ratios that cannot be weighed against the costs of interventions. Once more, PSMs can be designed to provide outputs in terms of value-relevant effects that are modulated against exposure and that can provide a better basis for decision making than arbitrary ratios or threshold values. Recent developments in the modeling and its potential for implementation by risk assessors and risk managers are beginning to demonstrate how PSMs can be practically applied in risk assessment and the advantages that doing so could have.

Use of the ecosystem services concept in ecological risk assessment of chemicals.

The reason for expressing ecological protection goals in terms of ecosystem services is to make a connection between ecosystems and what people get out of them in terms of marketed goods and nonmarketed welfare. Here our focus will be on how the ecosystem services framework is and can be applied to the ecological risk assessment (ERA) of chemicals. We provide 2 contrasting examples of how the ecosystem services framework is currently being applied in regulatory risk assessment, and we discuss the challenges and knowledge gaps that need to be addressed if such a framework is to substantially improve ERAs and their ability to inform management decisions. We make the point that formulating protection goals in terms of ecosystem services only makes sense if they can be used in managing environmental impacts and if they are useful in informing the risk assessments behind these. Ecosystem services can make a contribution to management by connecting ecosystem structure and process to what is valued, and analyzing risk in this context is a way of making risk assessment more policy- and value-relevant. Using an ecosystem services framework to its fullest potential to support ERA will require the successful development of a suite of coupled Valuation Methods, Ecological Production Functions, and Mechanistic Effect Models that will require the establishment of strong multidisciplinary collaborations among ecologists, computer scientists, social scientists, and possibly others. In addition, buy-in from environmental decision makers and other stakeholders will be crucial. Some progress is being made on the research front, and the implementation of new legislation is providing incentives for developing risk assessment outputs that are much more directly related to environmental protection goals than those used currently.

Promises and problems for the new paradigm for risk assessment and an alternative approach involving predictive systems models.

The need for cost-effective risk assessment of chemicals is leading to the development of a reductionist paradigm that tries to assess impacts on humans and ecosystems from molecular changes. However, the biggest challenge for this paradigm comes from the emergence of properties that arise out of the interactions of the parts that are not included and yet which are key for assessing likely impacts. Although identifying key events and adverse outcome pathways can shed light on the involvement of important metabolic processes in toxicity, this does not mean that particular molecular initiating events are likely to be robust or accurate predictors of impacts that matter. There are even greater challenges for the new paradigm applied to ecological systems than to human health because of the need to link across more levels of biological organization. The present study argues for a predictive systems approach that makes the linkages through systems models in a mechanistic way that allows for emergence and that also has the potential for reducing the costs and use of animals in ecological risk assessments.

Quantitative risk assessment of contact sensitization: clinical data to assess utility of the model.

BACKGROUND: Contact hypersensitivity quantitative risk assessment (QRA) for fragrance ingredients is being used to establish new international standards for all fragrance ingredients that are potential skin sensitizers. OBJECTIVE: The objective was to evaluate the retrospective clinical data on three fragrance ingredients in order to provide a practical assessment of the predictive value of the QRA approach. It is important to have data to assess that the methodology provides a robust approach for primary prevention of contact sensitization induction for fragrance ingredients identified as potential sensitizers. METHODS: This article reviews clinical data for three fragrance ingredients-cinnamic aldehyde, citral, and isoeugenol-to assess the utility of the QRA approach for fragrance ingredients. RESULTS: This assessment suggests that had the QRA approach been available at the time standards were established for these fragrance ingredients, the clinical response might have been noticeably improved. Prospectively, with the establishment of QRA-derived standards, there should be a continued downward trend in patch test-positive rates for cinnamic aldehyde, citral, and isoeugenol over time. CONCLUSION: While it is recognized that the availability of retrospective data is limited, a longitudinal review of these data gives confidence that the QRA approach should be an effective tool for primary prevention. This study also highlights the importance of continued active monitoring of clinical patch-test data for fragrance ingredients.