Reports

The Rapid Androgen Disruption Activity Reporter (RADAR) Test Guideline describes an aquatic assay that utilizes transgenic Oryzias latipes (O. latipes, Japanese medaka) eleutheroembryos at day post hatch zero, in a multi-well format to detect chemicals active on the androgen axis. The RADAR assay was designed as a screening tool to provide a short-term assay to measure the response of eleutheroembryos to chemicals potentially active on the androgen axis. Test organisms are exposed for 72 hours in six-well plates in the presence and absence of a co-treatment with 17-methyl testosterone. The assay comprises five concentrations of the test chemical. At the end of the exposure, fluorescence imaging is measured and transformed into a numerical format; the statistical analysis and data interpretation procdure enable to determine whether the test chemical is considered active or not active.

The method permits estimation of an LD50 with a confidence interval and the results allow a substance to be classified for acute toxicity according to the Globally Harmonised System of classification and labelling of chemicals. It is easiest to apply to materials that produce death within couple of days. This Test Guideline is intended for use with rodents (rat female preferably). There are a limit test and a main test. The limit test can be used efficiently to identify chemicals that are likely to have low toxicity. The test substance is administered generally in a single dose by gavage to animals fasted prior to dosing. Single animals are dosed in sequence usually at 48h intervals. The first animal is dosed a step below the best preliminary estimates of the LD50. The second animal receives a lower dose (if the first animal dies) or a higher dose (if the first animal survives). Animals are observed with a special attention given during the first 4 hours and daily thereafter, for a total of 14 days generally. Weights Animals should be determined at least weekly. All the animals should be subjected to gross necropsy. Globally the LD50 is calculated using the maximum likelihood method. Following this, it may be possible to compute interval estimates for the LD50; most narrow is the interval and better is LD50 estimation. Software to be used with TG 425, 432, 455. Click here. Software not part of the Mutual Acceptance of Data.

Volume 9 of the Series compiles the biosafety consensus documents developed by the OECD Working Party on the Harmonisation of Regulatory Oversight in Biotechnology from 2019 to 2021. It deals with the biology of APPLE, SAFFLOWER and RICE, three important crops for agriculture and consumption worldwide. For each plant species, the book includes elements of taxonomy, morphology, centres of origin, life cycle, reproductive biology, genetics, outcrossing, crop production and cultivation practices, interaction with other organisms, main pests and pathogens, and biotechnological developments. The science-based information collated here is available for use during the risk assessment of transgenic varieties intended for release in the environment. Prepared by authorities from OECD Members and other economies associated with the work, this publication should be of value to crop breeders, applicants for agricultural production of new varieties of apple, safflower and rice, national regulators and risk assessors when conducting biosafety assessments on these varieties obtained from modern biotechnology, as well as the wider scientific community. More information is found at BioTrack Online.

The development of plastic products does not systematically take sustainability, particularly from a chemicals perspective, into account. This report seeks to enable the creation of inherently sustainable plastic products by integrating sustainable chemistry thinking in the design process. By applying a chemicals lens during the plastic material selection process, designers and engineers can make informed decisions to incorporate sustainable plastic during the conceptualisation phase of their products. The report provides an integrated approach to sustainable plastic selection from a chemicals perspective, and identifies a set of generalisable sustainable design goals, life cycle considerations and trade-offs. At a more granular level, considerations are identified for each life-cycle phase, which are brought together as a whole-product assessment and optimisation taking the full life cycle into account. The report also considers trade-offs that will need to be carefully balanced in the design phase and reflection on implications of design choices. Ultimately, the report helps to equip designers and engineers with knowledge of relevant chemical considerations when selecting sustainable plastic, supporting better outcomes and a more transparent process.

A clear, efficient, and modern regulatory framework for pesticides is essential for addressing their impacts on human health and the environment, supporting a life-cycle approach to their management, and ensuring crop protection and a sustainable agricultural industry. This report identifies the gaps, barriers, implementation flaws and inefficiencies that affect the regulatory framework of pesticides in Mexico. It takes stock of the regulatory framework and recent reforms, and identifies both the areas that pose the greatest challenge for the effective regulation of pesticides and those where regulation – or lack of it – in pesticides most affects policy objectives and economic activity. These challenges and practices are assessed in view of OECD principles and country experiences, and recommendations are provided to support better regulation efforts. The report finds that Mexico would benefit from adopting a comprehensive, mutually-agreed policy strategy for pesticides, recognising that pesticide management is a shared responsibility across national and local governments, the pesticide industry, pesticide users, as well as the general public.

A Defined Approach (DA) consists of a selection of information sources (e.g in silico predictions, in chemico, in vitro data) used in a specific combination, and resulting data are interpreted using a fixed data interpretation procedure (DIP) (e.g. a mathematical, rule-based model). DAs use methods in combination and are intended to overcome some limitations of the individual, stand-alone methods. The first three DAs included in this Guideline use combinations of OECD validated in chemico and in vitro test data, in some cases along with in silico information, to come to a rules-based conclusion on potential dermal sensitisation hazard. The DAs included in this Guideline have shown to either provide the same level of information or be more informative than the murine Local Lymph Node Assay (LLNA; OECD TG 429) for hazard identification (i.e. sensitiser versus non-sensitiser). In addition, two of the DAs provide information for sensitisation potency categorisation that is equivalent to the potency categorisation information provided by the LLNA.

The RTgill-W1 cell line assay describes a 24-well plate format fish cell line acute toxicity test using the permanent cell line from rainbow trout (Oncorhynchus mykiss) gill, RTgill-W1. After 24 h of exposure to the test chemical, cell viability is assessed based on three fluorescent cell viability indicator dyes, measured on the same set of cells. Resazurin enters the cells in its non-fluorescent form and is converted to the fluorescent product, resorufin, by mitochondrial, microsomal or cytoplasmic oxidoreductases. A reduction in the fluorescence of resorufin indicates a decline in cellular metabolic activity, including disruption of mitochondrial membranes. The data are expressed as the percent cell viability of unexposed control values versus the test chemical concentration. The resulting concentration-response curves serve to determine the effective concentrations causing 50% loss in cell viability, i.e. the EC50 value. The test is designed to (i) predict fish acute toxicity in product testing; (ii) range-finding and pre-screening before conducting a full fish acute or other fish-based toxicity test; (iii) generation of toxicity information to be used for hazard assessment in combination with other lines of evidences (e.g., Quantitative Structure Activity Relationships (QSAR), weight of evidence (WoE)) within Integrated Testing Strategy (ITS)/Integrated Approach to Testing and Assessment (IATA).

Crop field trials are conducted to determine the magnitude of the pesticide residue in or on raw agricultural commodities, including feed items, and should be designed to reflect pesticide use patterns that lead to the highest possible residues. Objectives of crop field trials are to: (1) quantify the expected range of residue(s) in crop commodities following treatment according to the proposed or established good agricultural practice; (2) determine, when appropriate, the rate of decline of the residue(s) of plant protection product(s) on commodities of interest; (3) determine residue values such as the 'Supervised Trial Median Residue' and 'Highest Residue' for conducting dietary risk assessment; and (4) derive maximum residue limits (MRLs).  This Test Guideline requires one sample from treated plots at each sampling interval for crops that have eight or more crop field trials. The test substance(s) should be stored under appropriate conditions for the study duration and applied soon after preparation or mixing. Test substance applications should not be made in strong wind, during rain or when rainfall is expected shortly after application. For all applications, the application rate should be expressed in terms of amount of product and/or active ingredient per unit area. At the end of each crop field trial, the (stored) samples are analysed for residue level (expressed for example in mg/kg).

The EASZY assay is a mechanism-based in vivo screening assay designed to detect endocrine active chemicals acting as agonist through estrogen receptors (ERs), by inducing the expression of the green fluorescent protein (GFP) driven by the cyp19a1b promoter. The EASZY assay allows for the detection of estrogenic activity of chemicals on transgenic tg(cyp19a1b:GFP) Zebrafish embryos exposed for 96 hours during the embryonic stages of development. At the end of the experiment, the fluorescence of each newly hatched eleutheroembryo is measured using fluorescence microscope. Because the skull of early developmental stages of zebrafish is transparent, GFP is observed, imaged and quantified in vivo. The intensity of fluorescence is then quantified using image analysis software.