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The importance of considering the bioavailability of metals in understanding and assessing their toxicity in freshwaters has been recognized for many years. Currently, biotic ligand models (BLMs) are being applied for the derivation and implementation of environmental quality standards (EQS) for metals under the Water Framework Directive in Europe. bio-met is a simplified tool that was developed for implementing bioavailability-based EQS for metals in European freshwaters. We demonstrate the reliability of the relationship between the full BLM predictions and the thresholds (hazardous concentration affecting 5% of species [HC5] values) predicted by bio-met in 3 stages, for the metals copper, nickel, and zinc. First, ecotoxicity data for specific species from laboratory tests in natural waters are compared with predictions by the individual species BLMs included in the full BLMs. Second, the site-specific HC5 values predicted by bio-met for the natural waters used for ecotoxicity testing are compared with those provided by the full BLMs. The reliability of both relationships is demonstrated for all 3 metals, with more than 80% of individual species BLM predictions being within a factor of 3 of the experimental results, and 99% of bio-met local HC5 predictions being within a factor of 2 of the full BLM result. Third, using a larger set of European natural waters in addition demonstrates the reliability of bio-met over a broad range of water chemistry conditions. bio-met is therefore an appropriate tool for performing compliance assessments against EQS values in Europe, due to the demonstrated consistency with the toxicity test data. Environ Toxicol Chem 2020;39:2361-2377. © 2020 SETAC.

Funding Information: The authors thank Prof. Paul Hewett (Exposure Assessment Solutions, Inc., Morgantown, WV) for his assistance with revising the probabilistic exposure model parametrization and interpretation of the results. Publisher Copyright: © 2021 Koivisto AJ et al. Background: The Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation requires the establishment of Conditions of Use (CoU) for all exposure scenarios to ensure good communication of safe working practices. Setting CoU requires the risk assessment of all relevant Contributing Scenarios (CSs) in the exposure scenario. A new CS has to be created whenever an Operational Condition (OC) is changed, resulting in an excessive number of exposure assessments. An efficient solution is to quantify OC concentrations and to identify reasonable worst-case scenarios with probabilistic exposure modeling. Methods: Here, we appoint CoU for powder pouring during the industrial manufacturing of a paint batch by quantifying OC exposure levels and exposure determinants. The quantification was performed by using stationary measurements and a probabilistic Near-Field/Far-Field (NF/FF) exposure model. Work shift and OC concentration levels were quantified for pouring TiO 2 from big bags and small bags, pouring Micro Mica from small bags, and cleaning. The impact of exposure determinants on NF concentration level was quantified by (1) assessing exposure determinants correlation with the NF exposure level and (2) by performing simulations with different OCs. Results: Emission rate, air mixing between NF and FF and local ventilation were the most relevant exposure determinants affecting NF concentrations. Potentially risky OCs were identified by performing Reasonable Worst Case (RWC) simulations and by comparing the exposure 95 th percentile distribution with 10% of the occupational exposure limit value (OELV). The CS was shown safe except in RWC scenario (ventilation rate from 0.4 to 1.6 1/h, 100 m 3 room, no local ventilation, and NF ventilation of 1.6 m 3/min). Conclusions: The CoU assessment was considered to comply with European Chemicals Agency (ECHA) legislation and EN 689 exposure assessment strategy for testing compliance with OEL values. One RWC scenario would require measurements since the exposure level was 12.5% of the OELV.

BACKGROUND Standard approaches for the assessment of Man via the Environment exposure are designed to be conservative. However, propagating these exposures into health impact assessment might lead to questionable socio-economic costs. OBJECTIVE The objective of this study was to develop a novel tiered modelling approach to assess human exposure to lead (Pb) via the environment. METHOD The approach starts in Tier 1 from EUSES modelling approach, modified with metal specific transfer factors. The generic Tier 2 approach uses the higher tier model GPM for air quality, and dietary exposure modelling based on EFSA's Comprehensive Food Database, in combination with crop specific transfer factors. Tier 3 considers additional site-specific information such as proximity of inhabitants and agricultural activities in relation to industrial sites. RESULTS This tiered modelling approach was applied to a case study of 50 lead battery manufacturing and recycling sites across Europe. Data sets from general population human biomonitoring studies were used to compare the predicted additional bioburden of Pb resulting from lead battery manufacturing and recycling. The higher tier assessments were able to demonstrate a >20-fold reduction in modelled Pb exposure compared to default assumptions made in Tier 1. SIGNIFICANCE Leading to better estimates for socio-economic costs in health impact assessment.

MERLIN-Expo merges and integrates advanced exposure assessment methodologies, allowing the building of complex scenarios involving several pollution sources and targets. The assessment of exposure and risks to human health from chemicals is of major concern for policy and ultimately benefits all citizens. The development and operational fusion of the advanced exposure assessment methodologies envisaged in the MERLIN-Expo tool will have a significant impact in the long term on several policies dealing with chemical safety management. There are more than 30 agencies in Europe related to exposure and risk evaluation of chemicals, which have an important role in implementing EU policies, having especially tasks of technical, scientific, operational and/or regulatory nature. The main purpose of the present paper is to introduce MERLIN-Expo and to highlight its potential for being effectively integrated within the group of tools available to assess the risk and exposure of chemicals for EU policy. The main results show that the tool is highly suitable for use in site-specific or local impact assessment, with minor modifications it can also be used for Plant Protection Products (PPPs), biocides and REACH, while major additions would be required for a comprehensive application in the field of consumer and worker exposure assessment.

The European Union (EU) chemicals regulation Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) requires a hazardous substance registration to identify the uses of a substance and the corresponding conditions of safe use. This requirement includes a human and an environmental safety assessment. Exposure scenarios are developed and employed for estimating emissions resulting from the uses of hazardous substances. To support the environmental assessments, the REACH guidance documents define 22 environmental release categories (ERCs) with conservative release factors (RFs) to water, air, and soil. Several industry associations target the ERCs to more specific uses and respective emission scenarios to enable more realistic emission estimations. They have developed more than 190 specific ERCs (SPERCs) as standardized descriptions of operational conditions (OCs) and risk management measures (RMMs). SPERCs reflect the current good practice and are documented in factsheets. These factsheets contain the information necessary for environmental emission modeling. Key parameters are the substance use rate, the efficiency of the risk management measures (if applicable), and the RFs. These parameters can be based on literature or measured company data or are justified by qualitative arguments. The majority of SPERCs have been implemented as realistic worst-case emission values in screening-level chemical safety assessment (CSA) tools. Three regulatory reviews in Europe have established requirements for documenting the SPERCs and for justifying the RFs. In addition, each of the reviews included recommendations for improving the SPERCs. The latest review proposed a condensed factsheet that focuses on the essentials for exposure assessment and subsequent communication in safety data sheets. It is complemented with a background document for providing details on the emission scenarios and justifications. In the EU the SPERCs will be further progressed in a consensus process using the multi-stakeholder expert network on exposure scenarios. The SPERCs have the potential to be used in environmental risk assessments within other regulatory frameworks or in other geographical regions. Integr Environ Assess Manag 2016;12:772-781. © 2015 SETAC.

Several IT tools have been developed to facilitate the evaluation of complex inorganic materials, with the aim to support the assessor at specific steps of the assessment, such as the Metals Classification Tool (MeClas) for hazard identification and classification, or MEASE and specific environmental release categories (SPERCs) that generate exposure estimates. In addition, several tools have been made available by the scientific, regulatory, and industry communities to consider metal specificities such as bioavailability in the environment (Biomet, PNEC.Pro, M-BAT) and fate (TICKET-UWM). All these tools, easily accessible, are based on the current knowledge and are regularly updated to take into account new metal science and user-friendliness. The chapter provides a general overview of these tools as well as their principal features.

In addition to the approaches and tools currently used for the risk management of complex inorganic materials, new tools are being developed or further adapted towards the specificities of inorganic materials. Quantitative ion–character activity relationships and adverse outcome pathway analysis are promising tools to predict toxic effects or mode of actions for less data rich substances and can help to prioritise critical substances or constituents and endpoints. Promising models for predicting the combined toxicity of inorganics are being developed and can support decision-making for constituent-based risk assessment of complex inorganic materials. Life-cycle assessment approaches are a valuable tool to assess and compare impacts from substances or processes on a range of endpoints. However, such approaches need further standardisation and implementation of the inorganics’ specifics to allow a sound comparison of impacts from different types of (inorganic) materials. When further developed and accepted, all these tools will add to the risk management of complex inorganic materials.

The intrinsic variability in chemical composition and the sometimes unknown speciation of inorganic UVCBs (Unknown or Variable composition, Complex reaction products, or Biological materials) result in uncertainties during their assessment, requiring the development of a specific approach. The strategy for the assessment focuses on capturing the variability in composition using the knowledge of processes and input materials, defining the ranges in composition as well as the chemical speciation where applicable, compiling the hazard profiles of the constituents and classifying the UVCB based on the combination of these data. Elemental concentrations of the UVCB constituents are usually measured due to their economic value, allowing to document the variability in composition. Speciation, preset by the input material and process is not routinely quantified. Where the speciation of the constituent is unknown, the speciation with the worst-case classification can be taken forward for the calculation of the UVCB classification. For the risk assessment, the hazards of each constituent are assessed and the corresponding effect values (e.g. PNEC, DNEL) taken forward where a hazard is identified. Workplace monitoring and environmental release data as well as metal-specific models are used in exposure assessment. The potential combined exposure and toxicity of the UVCB constituents are assessed in a tiered way, starting from the conservative summation of the RCRs, further refined with additional information.

Accurate identification and evaluation of exposure/emissions along the entire life cycle of complex inorganic materials is crucial to ensure that the potentially associated environmental and health risks are properly managed. The evaluation of exposure/emissions shall cover the workplace (occupational exposure), the different environmental compartments (environmental exposure), the general population exposed to such materials indirectly via air, food, or drinking water or directly as potential consumers of preparations or goods containing such materials. This chapter describes the key elements of relevance when assessing exposure to complex inorganic materials (variability, speciation, physical form), including some general principles aiming at preventing/reducing exposure/emissions.

The MERLIN-Expo tool was evaluated using a SWOT analysis, which was based on expert judgement and literature review. A list of criteria was set up containing the major model characteristics, which were divided in general model criteria and relevance model criteria. Relevance model criteria were defined as criteria, which are highly depending on the regulatory framework the model is used in. From the analysis presented above, it appeared that certain regulatory chemical frameworks (e.g. REACH, biocides) are stricter towards their requirements compared to others (e.g. site-specific/local regulatory frameworks). Based on expert judgement, the MERLIN-Expo tool was evaluated using the general and relevance criteria. MERLIN-Expo has many advanced functionalities (such as uncertainty analysis, modular approach, dynamic model, combines environmental fate with pharmacokinetics) and models (many fate processes and environmental compartments, different human populations). At the same time, the threat is that current (regulatory) applicability frameworks do not always require these advanced assessment functionalities. The MERLIN-Expo tool appeared to be most suitable for the site-specific assessment as this is the most flexible framework. Based on this analysis, weaknesses of the MERLIN-Expo tool for its use in a certain regulatory framework could also be identified. These weaknesses are at the same time further development opportunities for MERLIN-Expo. On general model characteristics, MERLIN-Expo was identified as a highly documented (both for novice and expert level), transparent, user-friendly tool with regular trainings. Its main treat now is to ensure continuing support and mechanisms for future developmental work and updates.

At the example of the MERLIN-Expo case study, important aspects of the documentation and of standardisation of chemical exposure models are discussed. A key challenge faced by developers of large or complex chemical exposure models is limited transparency leading to loss of confidence in the applicability of results of the model and other inefficiencies such as lacking interoperability. These inefficiencies can be addressed by standardisation which is explained as a process leading to improved common definitions, transparency and reliability in application. A review of available frameworks on the documentation of exposure models as well other complex models is conducted. The process of arriving at consensus on recommended documentation of exposure models via a workshop process is described, involving representatives from different stakeholders such as scientists, regulators, manufacturers or consultants. Key components of the documentation of chemical exposure models are presented, and a way to structure the communication of the information is proposed. The role of standardisation in supporting research and innovation projects is illustrated.

The assessment of environmental exposure and risks associated with the production or use of a substance on an industrial site includes the estimation of the releases to the environment. In the absence of measured release data on the specific substance, a risk assessor would rely on default release factors to the environmental compartments as developed in international, national, or regional context. Because a wide variety of substances, processes, and uses has to be covered, default release factors are as a rule conservative, usually leading to significant overprediction of releases and hence to overpredicted environmental exposure concentrations and risks. In practice, unrealistic and worst-case predictions do not support a more efficient management of releases and risk. The objective of this article is to propose a more realistic approach to characterize the environmental releases from manufacture, processing, and downstream uses of the metals and their compounds. Although developed in the European Union (EU), this approach can also be used in other regions and in other chemical management systems addressing metals. A database consisting of more than 1300 recent (1993–2010), site-specific measured release factors to air and water of 18 different metals from various EU Member States was compiled and used to calculate average and reasonable worst-case release factors for multiple metal manufacture and industrial use processes. The parameters influencing releases to water were found to depend predominantly on life cycle step (manufacture and/or use), the sector and/or the solid–water partition coefficient (Kd). The release factors can be used as advanced tier instrument in environmental safety assessments, increasing the realism of the estimates while still keeping a sufficient level of conservatism. Integr Environ Assess Manag 2014;10:529–538. © 2014 SETAC

The increasing efforts in reducing the emission of micropollutants (MP) into the natural aquatic environment require the development of modelling tools to support the decision making process. This article presents a library of dynamic modelling tools for estimating MP fluxes within Integrated Urban Wastewater and Stormwater system (IUWS - including drainage network, stormwater treatment units, wastewater treatment plants, sludge treatment, and the receiving water body). The models are developed by considering the high temporal variability of the processes taking place in the IUWS, providing a basis for the elaboration of pollution control strategies (including both source control and treatment options) at the small spatial scale of urban areas. Existing and well-established water quality models for the different parts of the IUWS (e.g. ASM models) are extended by adding MP fate processes. These are modelled by using substance inherent properties, following an approach commonly used in large-scale MP multimedia fate and transport models. The chosen level of complexity ensures a low data requirement and minimizes the need for field measurements. Next to a synthesis of model applications, a didactic example is presented to illustrate the potential of the use of the developed model library for developing, evaluating and comparing strategies for reduction of MP emissions from urban areas. Display Omitted We created a model library for dynamic modelling of micropollutant fluxes in cities.The IUWS_MP model library includes sewer, treatment options and receiving waters.IUWS_MP combines existing models for evaluating pollution control strategies.Dynamic modelling allows estimation of both MP fluxes and concentrations.A didactic example showing the potential of the developed tool is presented.

Vertebrate testing under the European Union's regulation on Registration, Evaluation, Authorisation and Restriction of Chemical substances (REACH) is discouraged, and the use of alternative nontesting approaches such as quantitative structure-activity relationships (QSARs) is encouraged. However, robust QSARs predicting chronic ecotoxicity of organic compounds to fish are not available. The Ecological Structure Activity Relationships (ECOSAR) Class Program is a computerized predictive system that estimates the acute and chronic toxicity of organic compounds for several chemical classes based on their log octanol-water partition coefficient (K(OW)). For those chemical classes for which chronic training data sets are lacking, acute to chronic ratios are used to predict chronic toxicity to aquatic organisms. Although ECOSAR reaches a high score against the Organisation for Economic Co-operation and Development (OECD) principles for QSAR validation, the chronic QSARs in ECOSAR are not fully compliant with OECD criteria in the framework of REACH or CLP (classification, labeling, and packaging) regulation. The objective of the present study was to develop a chronic ecotoxicity QSAR for fish for compounds acting via nonpolar and polar narcosis. These QSARs were built using a database of quality screened toxicity values, considering only chronic exposure durations and relevant end points. After statistical multivariate diagnostic analysis, literature-based, mechanistically relevant descriptors were selected to develop a multivariate regression model. Finally, these QSARs were tested for their acceptance for regulatory purposes and were found to be compliant with the OECD principles for the validation of a QSAR.

International audience; An important step in building a computational model is its documentation; a comprehensive and structured documentation can improve the model applicability and transparency in science/research and for regulatory purposes. This is particularly crucial and challenging for environmental and/or human exposure models that aim to establish quantitative relationships between personal exposure levels and their determinants. Exposure models simulate the transport and fate of a contaminant from the source to the receptor and may involve a large set of entities (e.g. all the media the contaminants may pass though). Such complex models are difficult to be described in a comprehensive, unambiguous and accessible way. Bad communication of assumptions, theory, structure and/or parameterization can lead to lack of confidence by the user and it may be source of errors. The goal of this paper is to propose a standard documentation protocol (SDP) for exposure models, i.e. a generic format and a standard structure by which all exposure models could be documented. For this purpose, a CEN (European Committee for Standardisation) workshop was set up with objective to agree on minimum requirements for the amount and type of information to be provided on exposure models documentation along with guidelines for the structure and presentation of the information. The resulting CEN workshop agreement (CWA) was expected to facilitate a more rigorous formulation of exposure models description and the understanding by users. This paper intends to describe the process followed for defining the SDP, the standardisation approach, as well as the main components of the SDP resulting from a wide consultation of interested stakeholders. The main outcome is a CEN CWA which establishes terms and definitions for exposure models and their elements, specifies minimum requirements for the amount and type of information to be documented, and proposes a structure for communicating the documentation to different users. © 2016 Elsevier B.V.

Little is known about the magnitude of the effects of lead shot ingestion alone or combined with poisons (e.g., in bait or seeds/granules containing pesticides) on population size, growth, and extinction of non-waterbird avian species that ingest these substances. We used population models to create example scenarios demonstrating how changes in these parameters might affect three susceptible species: grey partridge (Perdix perdix), common buzzard (Buteo buteo), and red kite (Milvus milvus). We added or subtracted estimates of mortality due to lead shot ingestion (4–16% of mortality, depending on species) and poisons (4–46% of mortality) reported in the UK or France to observed mortality of studied populations after models were calibrated to observed population trends. Observed trends were decreasing for partridge (in continental Europe), stable for buzzard (in Germany), and increasing for red kite (in Wales). Although lead shot ingestion and poison at modeled levels did not change the trend direction for the three species, they reduced population size and slowed population growth. Lead shot ingestion at modeled rates reduced population size of partridges by 10%, and when combined with bait and pesticide poisons, by 18%. For buzzards, decrease in mean population size by lead shot and poisons combined was much smaller (≤ 1%). The red kite population has been recovering; however, modeled lead shot ingestion reduced its annual growth rate from 6.5% to 4%, slowing recovery. If mortality from poisoned baits could be removed, the kite population could potentially increase at a rapid annual rate of 12%. The effects are somewhat higher if ingestion of these substances additionally causes sublethal reproductive impairment. These results have uncertainty but suggest that declining or recovering populations are most sensitive to lead shot or poison ingestion, and removal of poisoned baits can have a positive impact on recovering raptor populations that frequently feed on carrion.

The Water Framework Directive (WFD) has the objective of a catchment-oriented water quality protection for all European waters with the purpose of achieving a good ecological and chemical quality status by the year 2015. To that end, necessary measures should be identified and implemented, with the aim of progressively reducing pollution from priority substances. The objective of this paper is to demonstrate how a dynamic model of the integrated urban wastewater system (IUWS) can be used to test different emission reduction strategies for organic priority pollutants (PPs) in a semi-hypothetical case study on di(2-ethylhexyl)phthalate (DEHP). The IUWS is composed of coupled entities: sources, urban catchment surface (run-off/infiltration), sewer system, stormwater treatment unit, wastewater treatment plant (WWTP) including sludge handling, and receiving surface water (river). State-of-the-art dynamic fate models were selected from literature and extended with an organic pollutant fate sub-model. Dynamic DEHP release profiles were estimated using a dynamic model input generator and fed to the model to predict the fate and concentration of DEHP in each IUWS sub-system. The model was then used to test eight scenarios on environmental performance, namely (1) reduction of impervious urban area, (2) reduction of infiltration in the sewer system, (3) input reduction (excluding the main pollutant sources), (4) separating the combined sewer system, (5) treatment of stormwater by stormwater infiltration ponds (separate sewer systems), (6) placement of retention basins at main sewer junctions, (7) sand filtration of secondary effluent, and (8) pre-precipitation of phosphorous. The simulation results revealed that the most effective measure in terms of river water quality improvement for DEHP (annual average and spikiness reduction) and PP concentration in the disposed WWTP sludge, is reducing release of this substance into the environment, not surprisingly. In general, this will heavily depend on the parameterisation of the scenarios.

Dynamic priority pollutant (PP) fate models are being developed to assess appropriate strategies for limiting the release of PPs from urban sources and for treating PPs on a variety of spatial scales. Different possible sources of PP releases were mapped and both their release pattern and release factors were quantified as detailed as possible. This paper focuses on the link between the gathered PP sources data and the dynamic models of the urban environment. This link consists of (1) a method for the quantitative and structured storage of temporal emission pattern information, (2) the retrieval of spatial emission source data from a GIS covering the studied urban area, (3) the coupling of the (GIS-based) spatial emission source data with temporal emission pattern information and (4) the generation of PP release time series to feed the dynamic sewer catchment model. Steps 3 and 4 were included as the main features of a dedicated software tool. Finally, this paper also illustrates the method's applicability to generate model input time series for generic pollutants (N, P and COD/BOD) in addition to priority pollutants.

The European Water Framework Directive (WFD) aims at achieving a good ecological and chemical status of surface waters in river basins by 2015. The chemical status is considered good if the Environmental Quality Standards (EQSs) are met for all substances listed on the priority list and eight additional specific emerging substances. To check compliance with these standards, the WFD requires the establishment of monitoring programmes. The minimum measuring frequency for priority substances is currently set at once per month. This can result in non-representative sampling and increased probability of misinterpretation of the surface water quality status. To assist in the classification of the water body, the combined use of monitoring data and pollutant fate models is recommended. More specifically, dynamic models are suggested, as possible exceedance of the quality standards can be predicted by such models. In the presented work, four realistic scenarios are designed and discussed to illustrate the usefulness of dynamic pollutant fate models for implementing the WFD. They comprise a combination of two priority substances and two rivers, representative for Western Europe.

BIOMATH, Department of Applied Mathematics, Biometrics and Process Control, Ghent University 1 DTU Environment, Technical University of Denmark 2 EURAS, Ghent, Belgium 3 KERMIT, Department of Applied Mathematics, Biometrics and Process Control, Ghent University 4 modelEAU, Universite Laval, Quebec, Canada 5 Evaluating Source Control Options for Reducing Emissions of Micropollutants Quebec City, Canada, 6 October 2009

ObjectivesDietary intake of long-chain (LC)n-3 PUFA in developed countries is low compared with recommendations. Fish is naturally rich in LCn-3 PUFA, but is also a dietary source of heavy metals and organic pollutants. We investigated whether the recommendation for LCn-3 PUFA could be reached through fish consumption, without exceeding the provisional tolerable weekly intake of methylmercury (MeHg) and the tolerable weekly intake (TWI) of dioxin-like compounds. Also, the contribution of margarines enriched with LCn-3 PUFA was assessed.DesignPublished nutrient and contaminant data were used in a probabilistic model to calculate the simultaneous nutrient and contaminant intake for different fish consumption scenarios.ResultsThe Belgian recommendation for EPA + DHA (0·3 % of total energy intake) can be reached by consuming fatty fish a minimum of twice a week, or by varying between lean and fatty fish a minimum of three times a week. At this fish consumption level, MeHg intake is not an issue of toxicological concern. The intake of dioxin-like compounds approximates the TWI when consuming fatty fish more than twice a week, this being a potential toxicological risk because other food items also contribute to the weekly intake of dioxin-like compounds. Use of margarine enriched with LCn-3 PUFA can help to increase LCn-3 intake, on average by 159 mg/d.ConclusionsCombination of regular fish consumption (twice a week) with important contribution of fatty fish species, in combination with regular consumption of margarine enriched with EPA + DHA, can be advised to achieve the recommendation for LCn-3 intake.

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) is the new European chemical legislation which aims to assess risk or safety of tens of thousands of chemicals to improve the protection of human health and the environment. The chemical safety assessment process is of an iterative nature. First, an initial, worst-case assessment is conducted after which refinements are made until no risk has been estimated or the risk is adequately controlled. Wasting time and resources on additional testing and implementing risk management measures with low effect on risk conclusions should be avoided as much as possible. This paper demonstrates the usefulness of an intelligent data collection strategy based on a sensitivity (and uncertainty) analysis on the risk assessment model EUSES to identify and order the most important "within-EU-TGD-reducible" input parameters influencing the local and regional risk characterisation ratios. The ordering can be adjusted for the costs involved in additional testing (e.g. ecotoxicity, physico-chemical properties, emission estimates, etc.). The risk refinement tool therefore reduces the resources needed to obtain a realistic risk estimate (both less conservative and less uncertain) as efficient as possible.

The objective of the present study was to evaluate the patulin exposure of children consuming organic, handcrafted or conventional apple juice through a probabilistic approach and to evaluate the effectiveness of several risk management options aiming to reduce the risk for children due to patulin exposure. However, a large part of the data on patulin contamination of apple juice fell under the limit of detection (LOD). Different methods were tested to deal with these so-called left censored data and a uniform distribution with uncertain bounds was selected to handle this censorship. Variability and uncertainty assessment of patulin exposure showed that 0.9% [90% confidence interval (CI): 0.3–1.8%] of the children consuming only organic apple juice exceed the tolerable daily intake (TDI). For consumers of conventional and handcrafted apple juice this was respectively 0.1% [90% CI: 0–0.3%] and 0% [90% CI: 0–0.2%]. Reduction of the patulin contamination in apple juice to concentrations below 25 μg/kg reduced the percentage of the children exceeding the TDI to 0% [90%CI: 0–0.2%] for organic apple juice. Reduction of the apple juice consumption was less effective than a reduction of the patulin concentration in apple juice and is only useful when the patulin concentration of apple juice is below 25 μg/kg.

Seafood consumption is related to both favorable health benefits of nutrients and to potential adverse health impacts of chemical contamination. To quantify the magnitude of this dilemma, probabilistic intake assessments can be performed. One step in such a procedure involves the determination of nutrient and contaminant concentrations in seafood for which data need to be collected. This article describes the process of building up a database containing previously published contaminant concentrations in seafood, and defining input distributions characterizing the variability. During the constitution of the database, several problems influencing the comparability of the data were encountered related to (1) sampling plans of the published data; (2) sample handling prior to analysis; (3) analytical methodologies; (4) the format of reporting results; and (5) missing data. Different solutions for these methodological problems have been developed. Contaminant concentrations ranges per gram fresh weight...

The European Union (EU) chemicals regulation Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) requires a hazardous substance registration to identify the uses of a substance and the corresponding conditions of safe use. This requirement includes a human and an environmental safety assessment. Exposure scenarios are developed and employed for estimating emissions resulting from the uses of hazardous substances. To support the environmental assessments, the REACH guidance documents define 22 environmental release categories (ERCs) with conservative release factors (RFs) to water, air, and soil. Several industry associations target the ERCs to more specific uses and respective emission scenarios to enable more realistic emission estimations. They have developed more than 190 specific ERCs (SPERCs) as standardized descriptions of operational conditions (OCs) and risk management measures (RMMs). SPERCs reflect the current good practice and are documented in factsheets. These factsheets contain the information necessary for environmental emission modeling. Key parameters are the substance use rate, the efficiency of the risk management measures (if applicable), and the RFs. These parameters can be based on literature or measured company data or are justified by qualitative arguments. The majority of SPERCs have been implemented as realistic worst-case emission values in screening-level chemical safety assessment (CSA) tools. Three regulatory reviews in Europe have established requirements for documenting the SPERCs and for justifying the RFs. In addition, each of the reviews included recommendations for improving the SPERCs. The latest review proposed a condensed factsheet that focuses on the essentials for exposure assessment and subsequent communication in safety data sheets. It is complemented with a background document for providing details on the emission scenarios and justifications. In the EU the SPERCs will be further progressed in a consensus process using the multi-stakeholder expert network on exposure scenarios. The SPERCs have the potential to be used in environmental risk assessments within other regulatory frameworks or in other geographical regions. Integr Environ Assess Manag 2016;12:772-781. © 2015 SETAC.

The Monte Carlo technique can be used to propagate input variable uncertainty and parameter uncertainty through a model to determine output uncertainty. However, to carry out Monte Carlo simulations, the uncertainty distributions or the probability density functions (PDFs) of the model parameters and input variables must be known. This remains one of the bottlenecks in current uncertainty research in forest carbon flux modeling. Because forest carbon flux models involve many parameters, we questioned whether it is necessary to take into account all parameters in the uncertainty analysis. A sensitivity analysis can determine the parameters contributing most to the overall model output uncertainty. This paper illustrates the usefulness of the Monte Carlo simulation technique for ranking parameters for sensitivity and uncertainty in process-based forest flux models. The uncertainty of the output (net ecosystem exchange, NEE) of the FORUG model was estimated for the Hesse beech forest (1997). Based on the arbitrary uncertainty of ten key parameters, a standard deviation of 0.88 Mg C ha(-1) year(-1) NEE was found which is equal to 24% of the mean value of NEE. Sensitivity analysis showed that the overall output uncertainty of the FORUG model can largely be determined by accounting for the uncertainty of only a few key parameters. The results led to the identification of the key FORUG parameters and to the recommendation for a process-based description of the soil respiration process in the FORUG model.

Water Quality Criteria (WQC) for metals are usually based on single species laboratory toxicity data. The influence of water characteristics of the surface waters on bioavailability to freshwater organisms is hence neglected, along with regional and temporal variability of these water characteristics. A methodology is presented to account for regional and temporal variability in the WQC setting for copper in the United Kingdom and Sweden. Bioavailability models were applied in a Monte-Carlo approach to account for temporal variability and a Geographic Information System was used to account for geographical variability on the chronic copper toxicity to Daphnia magna and Pseudokirchneriella subcapitata. Fifth percentiles of distributions of the No Observed Effect Concentration (NOEC) for both model species were derived in both study regions. For P. subcapitata, it was demonstrated that this fifth percentile can vary by a factor 10 in the UK study region. The ratio of these NOEC fifth percentiles (D...

Within the context and scope of the forthcoming European Union chemical regulations (REACH), there is a need to be able to prioritise the chemicals for evaluation. Therefore, a simple, pragmatic and adequately conservative approach for the identification of substances of very low or no immediate concern at an early stage is presented. The fundamental principles and basic concepts are derived from the EU Technical Guidance Document and EUSES, and are translated into an easy-to-use rule-based system. For this development, the effect on risk characterisation ratios (RCRs) of the key environmental parameters in EUSES was quantified (taking into account several standardised chemical release scenarios). Using statistical analysis, ranges were identified for each key parameter, within which the end result of the assessment was not significantly affected. This information was then translated into a lookup table from which environmental risk characterisation ratios can be directly read as a function of a few parameters.

The characterisation of the risk of (new) chemicals to species/communities, when both the exposure/environmental concentration and effects (species sensitivity) are variable and uncertain, is the central issue in Probabilistic Environmental Risk Assessment. The spatial variability is one of the largest components of the total variability. This paper tries to explicitly account for this spatial variability by geo-referencing the exposure, effect and finally probabilistic risk. Geo-referencing makes the risk assessment more refined and realistic. In addition, it is also highlighted that geo-referencing the effects of chemicals (species sensitivity distribution) is still a large unexplored area but has large potential to improve probabilistic ecological risk assessments.

Uncertainty is a central concept in the decision-making process, especially when dealing with biological systems subject to large natural variations. In the design of activated sludge systems, a conventional approach in dealing with uncertainty is implicitly translating it into above-normal safety factors, which in some cases may even increase the capital investments by an order of magnitude. To obviate this problem, an alternative design approach explicitly incorporating uncertainty is herein proposed. A probabilistic Monte Carlo engine is coupled to deterministic wastewater treatment plant (WWTP) models. The paper provides a description of the approach and a demonstration of the general adequacy of the method. The procedure is examined in an upgrade of a conventional WWTP towards stricter effluent standards on nutrients. The results suggest that the procedure can support the decision-making process under uncertainty conditions and that it can enhance the likelihood of meeting effluent standards without entailing above-normal capital investments. The analysis led to reducing the capital investment by 43%, producing savings of more than 1.2 million euro.

Environmental standards must be set in ways which give full recognition to all sources of uncertainty and variability of the toxicity data used to derive these standards. Toxicity data such as NOECs form a variability distribution describing species sensitivity distribution (SSD). In EU environmental regulations the 5th-percentile of SSD is used to set the quality criteria. In this paper, a comparison is made between the application of techniques characterising uncertainty and variability (bootstrap, maximum likelihood estimation (MLE) and Bayesian approaches) using small toxicity data sets to calculate the 5th-percentile. Estimating lower and upper uncertainty bounds of a specific percentile gives different results when different methods are used. Bayesian and MLE methods were found to be superior to parametric bootstrapping because they are easier to use and not so computationally intensive.

Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model. Environ Toxicol Chem 2013;32:2507–2519. © 2013 SETAC

The environmental risks of 33 micropollutants occurring in Belgian coastal zone were assessed as single-substances and as mixtures. Water and sediment samples were taken in harbors, coastal waters and the Scheldt estuary during 2007–2009. Measured environmental concentrations were compared to quality standards such as Predicted No Effect Concentrations (PNECs), Environmental Quality Standards (EQSs), and Ecotoxicological Assessment Criteria (EAC). Out of a total of 2547 samples analyzed, 232 and 126 samples exceeded the EQS and EAC, respectively. Highest risks were observed for TBT, PBDEs, PCBs and the PAHs anthracene, indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene, benzo(k)fluoranthene, and benzo(b)fluoranthene in the water compartment and for TBT and PCBs in the sediment compartment. Samples taken at all stations during the April 2008 campaign indicate a potential risk of the contaminant mixtures to the aquatic environment (except W06 station). This study argues the need to revise quality standards when appropriate and hence the overall regulatory implication of these standards.

A risk assessment report (RAR) on zinc and zinc compounds has recently been prepared in the framework of the European Union (EU) Council Regulation 793/93/EEC on Existing Chemicals. The EU Scientific Committee on Human and Environmental Risks (SCHER) has, however, expressed some fundamental, science-based concerns about the approach followed and the conclusions. The main objective of the present study was to assess the potential environmental risks associated with current use patterns of Zn in nine EU river basins in Germany, France and Belgium, thereby using more advanced methodologies which are largely in line with the recommendations made by SCHER. This included (i) avoiding working with measured Zn concentrations from monitoring stations that were potentially influenced by point sources and/or historical contamination, (ii) the full bioavailability normalization of all chronic ecotoxicity data to river basin specific physico-chemistry using biotic ligand models (BLM), prior to deriving predicted no effect concentrations (PNEC) with the species sensitivity distribution (SSD) approach, and (iii) the use of a probabilistic framework for risk characterization. Further, a total risk approach instead of an added risk approach was used, and the PNEC was equated to the HC5-50 without an additional assessment factor. Based on monitoring data we estimated predicted environmental concentrations (PEC) for the different EU river basins between 1.3 and 14.6 microg dissolved Zn/L. PNEC values varied between 22.1 and 46.1 microg dissolved Zn/L. This resulted in deterministic risk characterization ratios (RCR) that were below 1 in all river basins, suggesting that there is no deterministic regional risk associated with current use patterns of Zn in these river basins. With the probabilistic approach we identified rather limited risks, i.e., between0.4 and 18.3%. When the EU RAR approach was applied to the same monitoring datasets, deterministic risks were found in different river basins. A detailed analysis showed that this different deterministic conclusion of risk is mainly due to the fact that the EU RAR (i) uses an additional assessment factor of 2 to derive the PNEC and (ii) uses a more conservative approach for implementing bioavailability (BioF approach). We argue that the larger conservatism in the EU RAR mainly originates from decisions made to deal in a pragmatic way with (i) uncertainty related to the across-species extrapolation of BLMs and (ii) the relatively high sensitivity of some multi-species toxicity studies.

Food intake is one of the principal exposure routes of polybrominated diphenyl ethers (PBDEs) in humans. This study focuses on fish consumption as a PBDE exposure route. A probabilistic intake assessment of PBDEs and healthy long chain omega-3 PUFAs (LC n-3 PUFAs) was conducted for Belgian fish consumers in order to study the balance of the intake of LC n-3 PUFAs and PBDEs. Based on the observed fish consumption level in the sample, the mean intake of brominated diphenyl ether (BDE)-28, 47, 99, 100, 153, and 154 via fish was 0.85 ng/kg body weight (bw)/day and the intake of LC n-3 PUFAs was 3.45 mg/kg bw/day, being low compared to the recommendations. Scenario analyses showed that consuming 150 g salmon twice a week is advisable to achieve the recommended LC n-3 PUFA intake with a rather low PBDE intake. When replacing 150 g salmon by herring, the PBDE intake is higher without an increase in LC n-3 PUFAs. In contrast, the combination of cod and salmon leads to a similar PBDE intake compared to twice a week salmon, but to a lower LC n-3 PUFA intake. In conclusion, the methodology presented in the paper allows balancing benefits and risks related to fish consumption.

Seafood represents a natural source of valuable nutrients (e.g., long chain omega-3 poly-unsaturated fatty acids (LC n-3 PUFAs), vitamin D, and iodine), but the favourable health perception is troubled by the presence of contaminants (e.g., PCBs, dioxin-like compounds, and (methyl) mercury (MeHg)). This dualism forms the basis for an important public health conflict. The objective of this study was to calculate and evaluate the simultaneous intake of multiple beneficial and harmful compounds (LC n-3 PUFAs, vitamin D, iodine, (Me)Hg, PCBs, and dioxin-like compounds) via seafood consumption in Belgium. A methodology and a software module were developed for executing probabilistic assessments of the simultaneous intake of multiple compounds leading to better insight in the problematic nature of food items involving both health benefits and risks. The simulations concerning seafood consumption in Belgium predicted that, as far as only seafood consumption is concerned, the considered populations do not reach a sufficiently high intake for the three nutrients considered (LC n-3 PUFAs, vitamin D, and iodine). Regarding the contaminants, (Me)Hg contamination of seafood on the Belgian market does not seem to be an issue of major toxicological concern. In contrast, for dioxin-like compounds the tolerable daily intake is reached by people with high seafood consumption.

Human consumption of seafood can be promoted because of its positive health effects. Conversely, it is a source of chemical contaminants. Due to this dilemma, a probabilistic intake assessment of nutrients and contaminants via seafood is of interest to provide more detailed information. A key component of such an assessment is the selection of the most appropriate input distributions to describe the consumption and concentration data. This paper describes the construction of a nutrient database, pooling vitamin D and omega-3 fatty acid concentrations in seafood from different publications and the encountered problems related to a lack or inconsistency of information given in these publications: food description, number of samples, sampling plan, sources of the values, limit of quantification (LOQ), etc. Different solutions have been proposed and the study resulted in a huge database allowing the description of distributions of vitamin D, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentration and their variability in 34 seafood species relevant for Belgian consumption. The distribution fitting and selection procedure resulted in different models for the different species and nutrients. The normal and lognormal distributions are most frequently used, followed by the uniform, beta and loglogistic distribution.

It is recognised that there is a need for a proper treatment and transparency of uncertainty in risk assessment and management, especially in view of the upcoming proposed new chemical policy REACH, which delegates the responsibility for conducting risk assessments to industry. The current EU risk assessment for new and existing substances is largely deterministic and prudential measures are implicitly embedded in calculation schemes and rules. In this paper, a more probabilistic approach to risk assessment is advocated. The advantage is twofold: 1) inherent variability and other uncertainty pertaining to exposure and effects are transparently taken into account, while at the same time 2) issues of caution are explicitly transferred to the risk management phase. The result of a probabilistic risk assessment as suggested is improved transparency with quantitative and qualitative uncertainty estimates. Such uncertainty information can be used to discuss precautionary measures in the context of risk management.

In probabilistic environmental risk assessment, the likelihood and the extent of adverse effects occurring in ecological systems because of exposure(s) to substances are estimated. It is based on the comparison of an exposure/environmental concentration distribution, with a species sensitivity distribution derived from toxicity data. The calculation of a probabilistic risk can be performed in many ways (e.g., area under the curve in joint probability curves). However, several (hypothetical) examples and some theoretical considerations illustrate that the current risk characterisation methods have an integrative character and they focus on the statistical comparison of two distributions without properly considering the environmental interpretation of these underlying distributions. Several scenarios with varying exposure/environmental concentration distribution and species sensitivity distribution standard deviations are discussed.

In the framework of the European Union (EU) New and Existing Chemicals Policy, a regional risk assessment for Zn according to the current technical guidance documents and a probabilistic approach, by mathematically integrating both best-fitting exposure concentrations and species-sensitivity distributions into a probabilistic risk quotient distribution using Monte Carlo analysis, was explored for The Netherlands. Zinc is an essential element, and the current probability distributions may not adequately deal with this property. The threshold Pareto distribution provided the best fit to the chronic Zn toxicity data, resulting in a predicted-no-effect concentration (PNECadd) for dissolved Zn of 34.2 microg/L, whereas use of the conventional normal distribution resulted in a PNECadd for dissolved Zn of 14.6 microg/L. The extracted exposure data resulted in a regional predicted environmental concentration (PEC) for dissolved Zn in the Dutch surface waters of 20.1 microg/L and in PECadd values for dissolved Zn of between 15.5 and 17.3 microg/L, depending on the background correction used. The conventional deterministic risk characterization identified a regional risk for Zn in the Dutch surface waters. The more comprehensive probabilistic approach used in the present study, however, identified only very limited potential risks for the Dutch region. A probabilistic median risk, that the environmental concentration is greater than the no-observed-effect concentration of a species in Dutch surface waters (0.5-0.6%), depending on the inclusion of background correction, was obtained from the best-fitting distributions. Because probabilistic approaches provide a quantifiable and improved assessment of risk and quantification of the uncertainty associated with that assessment, these techniques may be considered as a way to improve the EU risk assessment procedures for data-rich substances.

Up to now, within the design/retrofit of wastewater treatment plants (WWTPs), deterministic models were used to evaluate different scenarios on their merits in terms of effluent compliance. This paper describes an approach in which a Monte Carlo engine is coupled to a deterministic treatment plant model, followed by risk interpretation in the form of concentration - duration - frequency (cdf) curves of norm exceedance. The combination of probabilistic modelling techniques with the currently available deterministic models allows to determine the probability of exceeding the effluent limits of a WWTP. This percentage of exceedance is accompanied by confidence intervals resulting from the inherent uncertainty of influent characteristics and model parameters. The approach is illustrated for a hypothetical case study, consisting of a denitrifying plant model inspired by the benchmark model described by Spanjers et al.