Single‐use materials and poorly recycled waste in intensive care: An argument for improving sustainability

Intensive care unit (ICU) clinical items and packaging made from plastic, paper and other (mixed) materials have a significant environmental impact.1 These products are energy-intensive and generate a large carbon footprint and high levels of air pollution due to raw materials extraction, manufacture, distribution, use and disposal. Paper, glass and metal (steel, aluminium, etc.) pose less of a long-term threat than plastics because they can be relatively easily recycled and recycled almost indefinitely. This critical commentary offers a materials scientist perspective regarding the over-reliance on single-use plastic products and poor recycling in ICU settings to enable critical care nurses and their multi-disciplinary colleagues to understand the composition of health care products better. With improved knowledge about plastics and materials making up the clinical items used daily in ICUs, nurses will be more equipped to contribute to sustainable procurement and waste management, which are important aspects of national strategies to become a net zero health care system.2 In the United Kingdom, there is also now a ‘Design for Life roadmap’ providing national expectations to radically reduce single-use plastics in health care and maximize reuse, remanufacture and recycling.3 Plastics are wonderfully malleable and adaptable materials, with the physics term ‘plastic’ referring to the material's ability to be extensively deformed before breakage. The term is assumed to cover a single type of material, although the collective term includes more than 200 distinct chemical compounds. Traditional or conventional plastics are more correctly referred to as petrochemical-derived plastic (PDP) because they are wholly or in part derived from oil and natural gas. Plastics are polymers of linked single units or ‘string-like’ entities of varying molecular size (between tens of thousands to many millions). The bulk materials are also functionalized by incorporating additives, such as endocrine-disrupting plasticisers and preservatives, which can leach from the material. Plastics are a favoured material because they are cheap, versatile, easily shaped, accessible and chemically inert. PDPs offer physical protection against water, air, impact, distortion and temperature. Their chemical inertness is a threat and a “double-edged sword” in that it can lead to environmental persistence. The desirable properties of plastics include water repellence, mechanical toughness, rigidity and protection. ICU waste comes from many product types—consider how many clinical items are used daily, such as intravenous fluid bags and tubing, incontinence pads, syringes, sharps, medicine containers, personal protective equipment (PPE), catheters and supplies for ventilation, nutrition, suctioning and procedural packs (and the list could go on). Each item and its packaging contain many different materials, showing the complexity of the composition of health care products, and most with considerable amounts of plastics. For example, a syringe and needle consist of four types of plastic (polyethylene, PVC, polypropylene, cyclic olefin), rubber, paper, stainless steel and silicone oil lubricant across the device, container and wrapper. Plastic waste accounts for a significant amount of ICU waste, the majority of which is single-use plastic; however, plastic cannot be recycled for the same purposes very well. Consequently, any plastic waste can only be up-cycled and repurposed. Typically, this involves embedding the plastic waste throughout other materials, such as cement for the construction industries or a combination of molten plastic with sawdust, cotton fibre or sand to make composite materials for paving, fencing or furniture. Upon recycling, plastics undergo thermally-induced chain scission, consequently degenerating in quality. Other issues associated with SUPs and PDPs are materials supply from a finite resource and the lack of longer-term sustainability. In addition, the incineration of plastics liberates CO2 and other greenhouse gases (GHGs), exacerbating climate change. Upon landfill-disposal, paper and other compostable substances liberate methane (CH4), and materials such as nylon and food waste liberate nitrous oxide (N2O) and related oxides, referred to as NOx gases. These three specific gases are important because CO2 constitutes approximately 80% of all GHG emissions, while the other two account for 17%. CO2 is ascribed a global warming potential (GWP) value (over 100 years of persistence) of 1.0, while CH4 and N2O have GWP values that are 32 times and 280 times higher, respectively. This means 1 gram of CH4 is 32 times, and N2O 280 times, more influential in global warming than 1 gram of CO2. Nitrous oxide also has the impact of destroying atmospheric ozone, which protects the Earth from harmful ultraviolet light.4 Some recovery of the initial required energy to make the product can be obtained by energy recovery processes (incineration and recovery of some fraction of generated heat). However, this lies outside of a circular economy and generates GHGs that cause a rise in baseline GWP. Another strategy could involve sequestering and storage of materials, but again, this is a short-sighted view and only a short-term fix. Similarly, crude treatment and recovery of plastic materials give rise to modified materials with inferior chemical and physical or mechanical properties. Recycling policy can use the 3Rs (reduce, reuse, recycle) to reduce the number of new materials needed and the energy and pollution associated with this new or virgin material. Currently, only paper, metals and glass fare well during recycling. Polyester (PET) is the only plastic to be recycled multiple times without losing its valued properties.5 However, PET still has some limitations, with an estimated maximum of three to seven recycling cycles before it becomes unsuitable (poor and unworkable). Plastics degrade in the open air and seas due to oxygen-related oxidative change and mechanical action. This embrittling of the materials makes them subject to fragmentation and debriding, forming particles with sizes less than 5 mm width, referred to as microplastics. Very small versions of microplastics, called nano-particulates, are absorbed by marine flora and fauna and, therefore, indirectly into human bodies via the digestive tract.6 New evidence points to the disruptive action of these nanoplastics on human fertility, the endocrine system, the immune system, hepatotoxicity, nerve malfunction and oncogenesis.7 Given the persistence of plastics in the environment (air, land and sea) for an estimated 350–650 years, plastics accumulating in soil, air and ocean floor represent a real threat to ecosystems and humankind alike. Alternatives to PDPs include a range of short-lived (1–2 years) mixed materials, often called bioplastics or biopolymer composites. These commodities can use agricultural wastes, including sustainably sourced starting materials such as cellulose, starch, glycerol, bio-detergents and various plant oils or waxes. Plant oils or waxes can make the material more water-repellent. New candidates for such bioplastics include pressed dried plant cellulose, highly-compressed wood pulp, called glassine or heated starches and materials made from the products of microbial fermentation, such as polylactic acid (PLA)—lactic acid being the acid present in yoghurt. PLA is the cheapest of the most expensive mass-produced bioplastics on a weight-used basis at £1.6/kg compared with £3.2/kg for most other biopolymers; however, these costs are more expensive than £1.0–1.1/kg for almost all PDPs, creating a financial barrier.5 Bioplastics also have other environmental impacts when considering the full life cycle8 due to land use, pesticides, energy consumption, water use, greenhouse gas emissions, biodegradability and recyclability, although research to resolve these other issues indicates promise for bioplastics to potentially have a role in replacing traditional plastics.9 Other alternatives to current practice include re-engineering the thick walling of films, bottles and closures using supporting ridges, struts and baffles and “light weighting” to redesign and adjust the packaging to reduce its weight and waste produced.10 Substitution of the SUP polyethylene apron and other forms of PPE with waxed paper or glassine that can be rinsed, sterilized and recycled is another possibility. With its waxy character, calendar-rolled paper (called glassine) is an excellent replacement for plastic film. The material is converted back to wood pulp fibre after prolonged soaking in hot water and re-casting. The material degrades when buried in a matter of years rather than the many centuries of PDPs. Medical trays, holders, vessels and packaging for catering packs can also be made from recyclable and compostable paper. All health care departments, including resource-intensive areas like ICUs, produce large volumes of waste and must reconsider how plastics and plastic-based materials are currently used to find alternative solutions. Research and industry must collaborate to establish abundant, cheap alternative materials to PDPs. Where products need to be of single use, the materials should have identical or near-identical properties to those currently used yet be universally collected and recycled for similar or alternative use. Collection and processing of ICU waste must ensure alternatives to mass incineration and careful handling or disposal to limit entry into the natural environment. Preventing landfill-disposed waste from entering rivers, lakes, coastal water and deep-sea will avoid environmental persistence. There needs to be an urgent, collective, powerful drive to replace materials in health care clinical items, including those used in ICUs, with more reusable products and increased recycling when single-use product is required. As a large section of the health care workforce, this commentary calls out to critical care nurses to engage and collaborate with materials science, design, waste management and sustainability researchers to provide a valuable nursing perspective during this shift towards more environmentally sustainable ICU supplies. Data sharing is not applicable to this article as no new data were created or analyzed in this study.