Naixement de la societat de la informació

regulatory agencies, and international boundaries (I)

580

Environmental fate and exposure models: Advances and challenges in 21st century chemical risk assessment

M. Scheringer, ETH Zurich / Institute for Chemical and Bioengineering; A. Di Guardo, University of Insubria / Department of Science and High Technology; T. Gouin, TG Environmental Research / Safety and Environmental Assurance Centre; M. MacLeod, Stockholm University / Department of Environmental Science and Analytical Chemistry

Environmental fate and exposure models are a powerful means to integrate information on chemicals, their partitioning and degradation behaviour, the environmental scenario and the emissions in order to compile a picture of chemical distribution and fluxes in the multimedia environment. A 1995 pioneering book, resulting from a series of workshops among model developers and users, reported the main advantages and identified needs for research in the field of multimedia fate models. Considerable efforts were devoted to their improvement in the past 25 years and many aspects were refined: the inclusion of nanomaterials among the modelled substances, the development of models at different spatial and temporal scales, the estimation of chemical properties and emission data, the incorporation of additional environmental media and processes, the integration of sensitivity and uncertainty analysis in the simulations, etc. However, some issues are still challenging and require research efforts and attention: the need of methods to estimate partition coefficients for polar and ionizable chemical in the environment, a better description of bioavailability in different environments as well as the requirement of injecting more ecological realism in exposure predictions to account for the diversity of ecosystem structures and functions in risk assessment. Finally, to transfer new scientific developments into the realm of regulatory risk assessment, we propose the formation of expert groups that compare, discuss and recommend model modifications and updates and help develop practical tools for risk assessment.

581

Development and update of environmental exposure assessment tool EUSES for REACH and BPR Regulations

S. Frattini, ECHA-European Chemicals Agency; R. Cesnaitis, European Chemicals Agency; H. Schimmelpfenning, European Chemicals Agency ECHA; H. Magaud, European Chemical Agency ECHA

Introduction Both REACH Regulation and the Biocidal Products Regulation

requires that the chemicals addressed by the respective legislations are used safely. Both regulations require environmental exposure and risk assessment of chemicals. EUSES (the European Union System for the Evaluation of Substances) is a tool developed by authorities in the 90’s to support environmental exposure and risk assessment chemicals in line with the methods described in the technical guidance document (TGD 2003) that harmonised the assessments practices for these three policy areas at that time. EUSES last relevant update was in 2004, so that the tool is now partly outdated. An update is needed since the availability of an up-to-date tool is critical for both REACH and the BPR to function efficiently, both for applicants/registrants, MSCAs and ECHA. EUSES has several modules (release estimation, fate and distribution, effect assessment and risk characterisation). Fate and distribution module (including interaction with the release scenarios) as well as release estimation module are in the focus of the update process. Update needs and

developments The release, fate and distribution modules should be improved based

on the development having occurred over the last years, in particular: Implementation of existing and newly developed emission scenario documents (ESD) for biocides in the release module of EUSES. Complementing the release scenarios covered by EUSES. Expanding the applicability domain and exposure

estimation capability of the model. Alignment of the exposure estimation methods to the scientific developments over the last 20 years. Implement the new module of SimpleTreat (4.0). Exploring how to address site specific assessment by EUSES, like for example within authorisation process. A process has been initiated by ECHA with stakeholders to assess the need for update of EUSES. The kick off for this update process is a workshop with stakeholders which will take place in ECHA, in April 2018. The expected outcome of the workshop is the identification and prioritisation of the update needs and inputs on the update process set up (scientifically and IT support/setting). Workshop outcomes planned to be available before May 2018 and will be presented to the wider audience of the SETAC conference.

582

Advances in exposure assessment of fertilizers: development of a fertilizers environmental exposure tool and generic exposure scenarios under REACH

L. Della Pietra, Fertilizers Europe; S. Navis, Arche consulting / Laboratory of Aquatic Ecology, Evolution and Conservation; R. Puska, Yara Suomi; M. Bjørgan, Yara International ASA; K. Oorts, ARCHE

Fertilizers are considered as formulations and therefore no registration or chemical safety assessment is required under REACH. However, use of the individual constituents needs to be covered in the chemical safety reports (CSR) of the respective substances. Currently, exposure and risk assessment of fertilizer uses is mainly described in a qualitative way because of the lack of appropriate

environmental release categories (ERCs) and exposure models. Under the umbrella of Fertilizers Europe and the FARM REACH consortium, the fertilizer sector has developed a fertilizer sector uses map. In addition, four sector specific ERCs (SPERCs) were developed, by grouping similar uses, mainly based upon their physical form and application mode. Next, a Fertilizers Environmental Exposure tool (FEE) tool was developed, since in the standard REACH models for environmental exposure assessment (EUSES, ECETOC TRA, CHESAR), no local scenario for direct emissions to soil exists and direct releases from treated agricultural fields to surface water are not taken into account. In addition, important output pathways for fertilizers via crop uptake and harvest are generally not considered in these tools. Quantitative exposure scenarios, resulting in the calculation of realistic worst-case local Predicted Environmental Concentrations (PEC local) for fertilizer constituents in the various environmental compartments (soil, water, sediment) were established. The main focus of the FEE tool is on micronutrients such as manganese, copper and zinc, which are identified as hazardous for the aquatic environment; but the tool allows for assessment of other inorganic and organic substances in fertilizers as well. Conceptually, the tool has been based upon existing REACH exposure modelling, but is adapted for fertilizer uses by adopting relevant information of fate models from other chemical legislations. In order to improve harmonization and communication within the supply chain, generic exposure scenarios have been developed for a number of micronutrient and SPERC combinations. Collectively, the development of SPERCs, the fertilizers environmental exposure tool and generic exposure scenarios, allow for a systematic review of environmental exposure assessments of fertilizer compounds under the REACH legislation. Further information on the project, including downloads of the FEE tool and SPERC factsheets can be found via www.fertilizerseurope.com.

583

Bioaccessibility of grease thickeners and the implications for REACH registration

R.J. Brown, wca consulting; R. Smith, wca; P. Whitehead, wca consulting; J. Dawick, G. Whale, Shell Health / Risk Science Team; A. Dodos, Eldons; T. Halmans, Shell Global Solutions International / Anakytical Department An intrinsic component of greases are the grease thickeners which include a diverese range of substances including metal soaps, metal-complex soaps and polyureas. These different thickeners impart different technical properties on the final grease. Although individually registered under REACH as isolated substances (i.e. extracted from base oil), grease thickeners are typically manufactured in situ in base oil and seldom exist except within a grease base. Under normal environmental conditions, grease thickeners would be expected to remain within the grease base because, during the grease manufacturing process, unique physical interactions (or matrix effects) occur between the grease thickener and the base oil. These interactions are important because, to be effective, the grease thickener matrix has to keep the lubricating base oil entrained. It is proposed that these matrix effects have a significant impact on the bioaccessibility of the grease thickener substances

in situ in base oil in comparison to their isolated form. These matrix effects are

expected to decrease the bioaccessibility of the grease thickener as it is not available to cross an organism’s cellular membrane. The European REACH Grease Thickeners Consortium (ERGTC) have characterised the bioaccessibility of their grease thickeners by conducting leaching studies based on a Water Available Fraction” (WAF) approach, but using relevant media i.e. deionised water for the environment or synthetic fed state intestinal fluid (FeSSIF - Biorelevant, Switzerland) to assess exposure route via the gut (human health). Data is presented for different types of thickener substance which shows that most thickeners will not be bioaccessible and therefore, there will be minimal exposure to these substances. As the main form in which grease thickeners are manufactured and used, is

entrained in a grease base, it is proposed that a lack of exposure based on low solubilities and/or bioaccessability is taken into consideration when registering the substances under REACH. This is a pragmatic approach for a group of substances that have low hazard potential and avoids conducting unnecessary vertebrate animal testing. The ERGTC strategy for registering grease thickeners under REACH, taking into consideration bioaccessibility, will be presented, including proposed “limits for leaching”. This approach could be expanded to include other types of similar substances which occur in situ in an inert carrier such as base oil

584

The durability criteria: a pragmatic and sound approach to the exposure assessment of nano-enabled agrochemicals

M. Kah, University of Vienna / Department of Environmental Geosciences; R.S. Kookana, CSIRO / Land and Water

After many years of research and development, nano-enabled agrochemicals are starting to make their way into the market. Evaluating nano-enabled agrochemicals against conventional analogues is essential to assess the new risks and benefits associated with the technology, and this raises a number of issues for regulators. The ecological risk assessment of nano-enabled agrochemicals is likely to differ from that of conventional products and new parameters are needed to allow an adequate evaluation of the new products. The majority of products currently in development consists in nanocarrier systems loaded with a registered AI. For this type of products, a priority for assessment is to establish the time during which the AI remains associated with the nanocarrier, i.e. the “durability” of the

AI−nanocarrier complex [1]. Kookana et al. [2] presented a series of guiding principles for the regulatory evaluation of environmental risk associated with nano-enabled pesticides, including a conceptual strategy relying on the durability parameter. A group drawn from regulatory agencies, academia, research, and the agrochemicals industry recently offered a perspective on relevant considerations pertaining to the problem formulation phase [3]. A case study (pendimentalin nanosized hydrogel) was consider to test and the framework proposed for exposure assessment. The scheme serves as a useful base to guide additional data

requirement and help regulators to take informed decisions without having to systematically perform a comprehensive new nano-specific assessment. One of the key conclusions is that an early and reliable measure of the durabilityof the AI-nanocarrier complex under relevant conditions is key to the assessment of nano-enabled pesticides. There is currently no standard protocols to measure the durability of the AI−nanocarrier complex and robust methods for its measurement are urgently needed. References: 1. Kah M, Hofmann T. 2014. Environ. Int. 63:224–235. 2. Kookana RS et al. 2014. J. Agric. Food Chem. 62:4227–4240. 3. Walker GW et al. 2017. J. Agric. Food Chem. doi:10.1021/acs.jafc.7b02373.

585

Can we model emissions, fate and exposure on a global scale? A case study of PCB 153 in human milk

M. McLachlan, Stockholm University / Environmental Science and Analytical Chemistry (ACES); E. Undeman, Stockholm University / Baltic Sea Centre; F. Zhao, Stockholm University / Department of Environmental Science and Analytical Chemistry ACES; M. MacLeod, ITM - Stockholm University / Department of Environmental Science and Analytical Chemistry

One of the grand challenges of environmental chemistry is to be able to predict human exposure to an environmental contaminant based on its emissions. In this paper we explore how, after decades of excellent research by scores of scientists, we measure up to this challenge on a global scale. PCB 153, a widely studied persistent, hydrophobic and semi-volatile pollutant was chosen as the test chemical. We used physico-chemical properties recommended by Schenker et al.1 _{and global} historical emissions estimates developed by Breivik and co-workers2 _{to drive the} global multimedia fate and transport model BETR Global.3 _{The fugacities of PCB} 153 in air, water and soil, modeled at a spatial resolution of 3.75° × 3.75°, were re-gridded to give the historical fugacity records on the basis of individual countries. These were entered into the bioaccumulation and exposure model ACC-HUMAN, which modeled the concentrations of PCB 153 in fish, meat, dairy products and human milk.4 _{The human diet in ACC-HUMAN was parameterized} for each country based on the WHO Global Environment Modeling System (GEMS) cluster diets.5 _{The modeled concentrations of PCB 153 in human milk} were compared with the concentrations measured in the WHO/UNEP global monitoring program for POPs.6 _{The predicted and observed concentrations were} highly correlated, with a correlation coefficient of 0.76. For 49 out of 78 data points, the predictions and observations agreed within a factor of 4. The model

over-predicted the concentrations in central Europe and under-predicted the concentrations in much of Africa, in particular West Africa. Potential weaknesses identified in the chain of models include an under-prediction of the rate of decrease in PCB concentrations in air since the 1980s and inadequate treatment of food sourcing.7,8 _{We conclude that we have come a long way towards meeting this grand} challenge for PCB 153, but there remains room for improvement! References U. Schenker et al. Environ. Sci Technol., 2005, 39, 8434-8441. K. Breivik et al.,

Environ. Sci. Technol., 2016, 50, 798-805. M. MacLeod, et al., Environ. Pollut.,

2011, 159, 1442–1445. G. Czub and M. S. McLachlan, Environ. Toxicol. Chem., 2004, 23, 2356–2366.