Sediment-Air Partitioning of Hydrophobic Organic Chemicals.

Contaminated sediments that become exposed to the air as a result of dredging or water receding are potential sources of emissions of toxic compounds to the atmosphere. Exposure models are currently being developed to assess the risk associated with this pathway of contaminant release and to design efficient remediation techniques. A critical parameter in these emission models is the equilibrium partition coefficient of the contaminant between the sediment and the air. In this study, the sediment-air equilibrium partitioning of a polymiclear aromatic hydrocarbon (phenanthrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) was investigated. Both classes of compounds are commonly found in contaminated sediments and are known carcinogens. A gas saturation technique was used to study the influence of ambient temperature and sediment moisture content on the partition coefficient of the contaminants. The primary factor affecting the partitioning is the sediment moisture content (mc). Its variation from about 0% to 6% causes the partition coefficient to decrease by up to three orders of magnitude. Determination of phenanthrene\u27s heat of sorption in dry (mc = 0.3%) and wet (mc \u3e 6.0%) sediments indicates that different mechanisms of sorption exist in each moisture range. In the dry range, the contaminant is mainly adsorbed on the mineral surfaces of the sediment. When the moisture content increases, the competitive adsorption of water progressively displaces the contaminant from the mineral adsorption sites. Finally, in the wet range, the contaminant is mainly associated with the sediment organic matter. In addition, the physical state of water in the sediment as a function of moisture content was characterized by comparing the isotherm of water sorption to the pore-volume distribution. This permitted the estimation of the respective contributions of the various sorption mechanisms to the overall sediment-air partitioning process. A model of the sediment-air partition coefficient is proposed that accurately accounts for the observed variations resulting from changes in sediment moisture content

Advancing human health risk assessment

Acknowledgements: The European Food Safety Authority (EFSA) and authors wish to thank the participants of the break‐out session ‘Advancing risk assessment science – Human health’ at EFSA's third Scientific Conference ‘Science, Food and Society’ (Parma, Italy, 18–21 September 2018) for their active and valuable contributions to the discussion. We also thank Hans Verhagen for carefully proofreading it.Peer reviewedPublisher PD

BMC Sports Sci Med Rehabil

The main aim of this paper is to present the feasibility of rigorously designed multiple N-of-1 design in prosthetics research. While research of adequate power and high quality is often lacking in rehabilitation, N-of-1 trials can offer a feasible alternative to randomized controlled group trials, both increasing design power at group level and allowing a rigorous, statistically confirmed evaluation of effectiveness at a single patient level. The paper presents a multiple N-of-1 trial protocol, which aim is to evaluate the effectiveness of Unity, a prosthetic add-on suspension system for amputees, on patient-reported comfort during daily activities (main outcome measure), prosthesis wearing time, perception of limb-prosthesis fitting and stump volume and functional walking parameters. Multicenter, randomized, prospective, double-blind multiple N-of-1 trial using an introduction/withdrawal design alternating Unity connected/disconnected phases of randomized length on twenty patients with unilateral transtibial amputation. The primary outcome measure is the Prosthetic Socket Comfort Score (SCS), a validated measure of comfort, administered daily by an phone app designed for the study. Secondary outcomes measures will be collected during the 50 days period of the N-of-1 trial: (1) by the same app, daily for patient-reported limb-prosthesis fitting, stump volume variation, and daily wearing time of the prosthesis; (2) by a pedometer for the number of steps per day; (3) by blind assessors in the rehabilitation center during adjustment visits for functional walking parameter (L-Test, 6-minute walk test), and by the patient for the QUEST, and ABC-S. Effectiveness of the Unity system regarding SCS and daily secondary outcome measures will be tested by randomization test. The secondary outcome measures assessed during visits in the rehabilitation center will be analyzed by Non Overlap of All pairs. An estimate of the effect on the amputee population will be generated by aggregating each individual clinical trial (N-of-1 trial) by Hierarchical Bayesian methods. This study protocol was designed to answer the question "which device is best for THIS patient" and to conclude at a group level on the effectiveness of a new devic, using a Multiple N-of-1 trial, which is promising but underused in prosthetics research so far. N° ID-RCB 2020-A01309-30 Clintrial.gov : NCT04804150 - Retrospectively registered March 20th 2021

Advancing human health risk assessment

The current/traditional human health risk assessment paradigm is challenged by recent scientific and technical advances, and ethical demands. The current approach is considered too resource intensive, is not always reliable, can raise issues of reproducibility, is mostly animal based and does not necessarily provide an understanding of the underlying mechanisms of toxicity. From an ethical and scientific viewpoint, a paradigm shift is required to deliver testing strategies that enable reliable, animal‐free hazard and risk assessments, which are based on a mechanistic understanding of chemical toxicity and make use of exposure science and epidemiological data. This shift will require a new philosophy, new data, multidisciplinary expertise and more flexible regulations. Re‐engineering of available data is also deemed necessary as data should be accessible, readable, interpretable and usable. Dedicated training to build the capacity in terms of expertise is necessary, together with practical resources allocated to education. The dialogue between risk assessors, risk managers, academia and stakeholders should be promoted further to understand scientific and societal needs. Genuine interest in taking risk assessment forward should drive the change and should be supported by flexible funding. This publication builds upon presentations made and discussions held during the break‐out session ‘Advancing risk assessment science – Human health’ at EFSA's third Scientific Conference ‘Science, Food and Society’ (Parma, Italy, 18–21 September 2018).publishe

Implementation of PROMETHEUS 4‐step approach for evidence use in EFSA scientific assessments: benefits, issues, needs and solutions

In 2014, the European Food Safety Authority (EFSA) started the PROMETHEUS (PROmoting METHods for Evidence Use in Scientific assessments) project to improve further and increase the consistency of the methods it uses in its scientific assessments. The project defined a set of principles for the scientific assessment process and a 4‐step approach (plan/carry out/verify/report) for their fulfilment, which was tested in ten case studies, one from each EFSA panel. The present report describes the benefits, issues, needs and solutions related to the implementation of the 4‐step approach in EFSA, identified in a dedicated workshop in October 2017. The key benefits of the approach, which was deemed applicable to all types of EFSA scientific assessment including assessments of regulated products, are: 1) increased ‘scientific value’ of EFSA outputs, i.e. the extent of impartiality, methodological rigour, transparency and engagement; 2) guarantee of fitness‐for‐purpose, as it implies tailoring the methods to the specificities of each assessment; 3) efficiency gain, since preparing a protocol for the assessment upfront helps more streamlined processes throughout the implementation phase; 4) innovation, as the approach promotes the pioneering practice of ‘planning before doing’ (well established in primary research) for broad scientific assessments in regulatory science; and 5) increased harmonisation and consistency of EFSA assessments. The 4‐step approach was also considered an effective system for detecting additional methodological and/or expertise needs and a useful basis for further defining a quality management system for EFSA's scientific processes. The identified issues and solutions related to the implementation of the approach are: a) lack of engagement and need for effective communication on benefits and added value; b) need for further advances especially in the field of problem formulation/protocol development, evidence appraisal and evidence integration; c) need for specialised expertise in the previous aspects; and specific needs for d) assessments of regulated products and e) outsourced projects