Key actions for a sustainable chemicals policy

Recovery of copper and silver from industrial e-waste leached solutions using sustainable liquid membrane technology: a review

Waste electrical and electronic equipment or e-waste has recently emerged as a significant global concern. This waste contains various valuable metals, and via recycling, it could become a sustainable resource of metals (viz. copper, silver, gold, and others) while reducing reliance on virgin mining. Copper and silver with their superior electrical and thermal conductivity have been reviewed due to their high demand. Recovering these metals will be beneficial to attain the current needs. Liquid membrane technology has appeared as a viable option for treating e-waste from various industries as a simultaneous extraction and stripping process. It also includes extensive research on biotechnology, chemical and pharmaceutical, environmental engineering, pulp and paper, textile, food processing, and wastewater treatment. The success of this process depends more on the selection of organic and stripping phases. In this review, the use of liquid membrane technology in treating/recovering copper and silver from industrial e-waste leached solutions was highlighted. It also assembles critical information on the organic phase (carrier and diluent) and stripping phase in liquid membrane formulation for selective copper and silver. In addition, the utilization of green diluent, ionic liquids, and synergist carrier was also included since it gained prominence attention latterly. The future prospects and challenges of this technology were also discussed to ensure the industrialization of technology. Herein, a potential process flowchart for the valorization of e-waste is also proposed.

Renewing and improving the environmental risk assessment of chemicals

The processes underpinning the environmental risk assessment (ERA) of chemicals have not changed appreciably in the last 30 years. It is unclear how successful these processes are in protecting the environment from any adverse effects of chemicals. To ascertain if the current methodology can be improved, and if so, how, we invited experts to suggest how the current ERA process could be improved. They were not asked to select from a list of suggestions. The 36 experts made 109 suggestions for improvement, which could be grouped into 33 categories. The category that received the most support, from 12 experts, was to utilise a broader range of scientific information, including all up-to-date information, in ERAs. The second most popular category, supported by 10 experts, was the suggestion to regulate mixtures of chemicals; the current regulatory process involves chemical-by-chemical assessment. Two quite radical proposals were suggested. One was to replace the regulator with artificial intelligence. The other was to establish a new competent authority that would appoint groups of experts, each including representatives of the range of stakeholders, to decide which studies were required, commission those studies, then conduct the ERA based on the results of those studies. These two radical proposals, which the authors support strongly, are not necessarily mutually exclusive. We conclude that the present ERA process could be improved to better protect the environment from the myriad of chemicals in use.

The Weight-of-Evidence Approach and the Need for Greater International Acceptance of Its Use in Tackling Questions of Chemical Harm to the Environment

As we attempt to manage chemicals in the environment we need to be sure that our research efforts are being directed at the substances of greatest threat. All too often we focus on a chemical of concern and then cast around for evidence of its effects in an unstructured way. Risk assessment based on laboratory ecotoxicity studies, combined with field chemical measurements, can only take us so far. Uncertainty about the range and sufficiency of evidence required to take restorative action often puts policymakers in a difficult situation. We review this conundrum and reflect on how the "Hill criteria," used widely by epidemiologists, have been applied to a weight-of-evidence approach (a term sometimes used interchangeably with ecoepidemiology) to build a case for causation. While using a set of such criteria to address sites of local environmental distress has been embraced by the US Environmental Protection Agency, we urge a wider adoption of weight-of-evidence approaches by policymakers, regulators, and scientists worldwide. A simplified series of criteria is offered. Progress will require a sustained commitment to long-term wildlife and chemical monitoring over a sufficient geographic spread. Development of a comprehensive monitoring network, coupled with assembling evidence of harm in a structured manner, should be the foundation for protecting our ecosystems and human health. This will enable us to not only judge the success or failure of our efforts but also diagnose underlying causes. Environ Toxicol Chem 2021;40:2968-2977. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.