Use of personal protective equipment (PPE) increased during the COVID-19 pandemic to reduce virus transmission. Here, we quantitatively analyse emergence of PPE and COVID-19-related litter over 14 months for 11 countries using the litter collection application Litterati. The proportion of masks in litter increased by >80-fold as a result of COVID-19 legislation, from <0.01% to >0.8%. Gloves and wipes, more prevalent at ~0.2% of litter before the pandemic, doubled to 0.4%, but this has since fallen. Glove litter increased in the initial stages of the pandemic but fell after the introduction of facemask policies, whereupon there was an increase of facemask litter. National COVID-19 policy responses and international World Health Organization announcements and recommendations are a probable driver of PPE litter dynamics, especially the implementation of facemask policies. Waste management should be incorporated in designing future pandemic policies to avoid negative environmental legacies of mismanaged PPE. The COVID-19 pandemic substantially altered consumption patterns, especially for health supplies such as personal protective equipment, including masks and gloves. This study of 11 countries examines both the rate and types of litter being discarded as a result of changing policies and recommendations during the first 14 months of the pandemic.

•Literature associated with ENM-containing waste was reviewed and summarized.•Knowledge gaps about ENM release during waste treatment exist.•Key processes and mechanisms of ENM fate and transport were reviewed.•Specific research questions have been identified.

Solid waste management (SWM) decision makers are under increasing pressure to implement strategies that are both cost effective and environmentally sound. Consequently, SWM has developed into a highly complex systemic planning problem and analytical tools are needed to assist in the development of more sustainable SWM strategies. Here, we present the Solid Waste Infrastructure Modelling System (SWIMS) software, which is the first non-linear dynamic, LCA-based optimisation tool for SWM that optimises for both economic and environmental performance. The environmental and economic costs of treating generated wastes at available treatment facilities are calculated through a series of life cycle process models, based on non-linear expressions defined for each waste material and each treatment process type. Possible treatment paths for waste streams are identified using a depth first search algorithm and a sequential evolutionary genetic algorithm is used to prioritise the order of these paths, in lieu of user defined optimisation criteria and constraints. SWIMS calculates waste arisings into the future and determines if it is possible to treat generated waste, while considering present and future constraints (e.g. capacity). If additional capacity is required, SWIMS will identify the optimum infrastructure solution to meet this capacity demand. A demonstrative case study of MSW management in GB from 2010 to 2050 is presented. Results suggest that sufficient capacity is available in existing and planned infrastructure to cope with future demand for SWM and meet national regulatory and legislative requirements with relatively little capital investment beyond 2020. SWIMS can be used to provide valuable information for SWM decision makers, particularly when used to analyse the effects of possible future national or regional policies.

Excessive accumulation of sediment‐associated organic matter in river beds has detrimental impacts on aquatic ecology, including fish. Sediment and source samples were collected from 3 headwater tributaries of the River Itchen, in southern England. Near infrared spectra and bulk stable carbon and nitrogen isotopes were employed as fingerprint properties to quantify the relative contributions from catchment‐based (farmyard manures/slurries, damaged road verges, and septic tanks) and channel‐based (decaying instream vegetation, watercress farms, and fish farms) sources. The findings suggested that over the duration of the sampling period, the final estimated median relative contributions in the Candover Stream subcatchment were in the order: farmyard measures/slurries 74% > decaying instream vegetation 15% > watercress farms 6% > septic tanks 3% > damaged road verges 2%. For the River Arle subcatchment, corresponding estimated median relative contributions were in the order: watercress farms 40% > farmyard manures/slurries 28% > decaying instream vegetation 21% > fish farms 7% > damaged road verges and septic tanks 2% each. Similar contributions were estimated for the Tichborne Stream subcatchment: watercress farms 36% > farmyard manures/slurries 26% > decaying instream vegetation 26% and damaged road verges and septic tanks at 6% each. These source apportionment estimates will contribute to stakeholder engagement and targeted management interventions.

The paper presents a three-stage framework for assessment of fluorescent dyes as tracers for use within Municipal Solid Waste (MSW) landfills. The value of tracer testing as a means of determining leachate behaviour and guiding leachate management strategies is explained. In the first stage, the fluorescence spectra of 27 leachates were compared with 30 fluorescent dyes, to find those dyes for which there was little interference from leachate. Fluorescein (Uranine), Eosin-Y and Rhodamine WT were selected. In a second stage, the dyes’ resistance to biodegradation by anaerobes was tested. Fluorescein and Rhodamine resisted degradation but Eosin was moderately degraded. In the final stage, all three dyes were sorbed on shredded MSW, with results fitted to Freundlich isotherms. It was concluded that Rhodamine WT was the most suitable quantitative tracer, as modelling its behaviour would require only a single parameter to be fitted. Eosin would require parameters for linear sorption and degradation. Fluorescein was shown to be an excellent qualitative tracer.

Oxygen demand in river substrates providing important habitats for the early life stages of aquatic ecology, including lithophilous fish, can arise due to the oxidation of sediment‐associated organic matter. Oxygen depletion associated with this component of river biogeochemical cycling, will, in part, depend on the sources of such material. A reconnaissance survey was therefore undertaken to assess the relative contributions from bed sediment‐associated organic matter sources potentially impacting on the River Axe Special Area of Conservation (SAC), in SW England. Source fingerprinting, including Monte Carlo uncertainty analysis, suggested that the relative frequency‐weighted average median source contributions ranged between 19% (uncertainty range 0–82%) and 64% (uncertainty range 0–99%) for farmyard manures or slurries, 4% (uncertainty range 0–49%) and 35% (uncertainty range 0–100%) for damaged road verges, 2% (uncertainty range 0–100%) and 68% (uncertainty range 0–100%) for decaying instream vegetation, and 2% (full uncertainty range 0–15%) and 6% (uncertainty range 0–48%) for human septic waste. A reconnaissance survey of sediment oxygen demand (SOD) along the channel designated as a SAC yielded a mean SOD 5 of 4 mg O 2 g −1 dry sediment and a corresponding SOD 20 of 7 mg O 2 g −1 dry sediment, compared with respective ranges of 1–15 and 2–30 mg O 2 g −1 dry sediment, measured by the authors for a range of river types across the UK. The findings of the reconnaissance survey were used in an agency (SW region) catchment appraisal exercise for informing targeted management to help protect the SAC.

The biodegradation of organic matter ingressing spawning gravels in rivers exerts an oxygen demand which is believed to contribute to detrimental impacts on aquatic ecology including salmonids. Catchment management strategies therefore require reliable information on the key sources of sediment-bound organic matter. Accordingly, a novel source fingerprinting procedure based on analyses of bulk stable C-13 and N-15 isotope values and organic molecular structures detected using near infrared reflectance (NIR) spectroscopy was tested for assessing the primary sources of sediment-bound organic matter infiltrating artificial Atlantic salmon spawning redds in five rivers across England and Wales. Statistically-verified source fingerprints were identified using a combination of the Kruskal-Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were obtained from artificial redds using retrievable basket traps inserted at the start of the salmonid spawning season and extracted subsequently in conjunction with critical juvenile phases (eyeing, hatch, emergence, late spawning) of fish development associated with incubation and emergence. Over the duration of these four basket extractions, the overall relative frequency-weighted average median source contributions to the interstitial sediment-bound organic matter sampled in the study rivers ranged between 26% (full uncertainty range 0-100%) and 44% (full uncertainty range 0-100%) for farm yard manures/slurries, 11% (full uncertainty range 0-75%) and 48% (full uncertainty range 0-99%) for damaged road verges, 16% (full uncertainty range (0-78%) and 52% (full uncertainty range (0-100%) for decaying instream vegetation and 4% (full uncertainty range 0-31%) and 10% (full uncertainty range (0-44%) for human septic waste. The results of mass conservation tests suggest that the procedure combining bulk C-13 and N-15 isotope values and NIR spectroscopy data on organic molecular structures is sensitive to the risks of significant non-conservative tracer behaviour in the fluvial environment and will therefore not necessarily work at all in-channel sites in all catchments. (C) 2014 Elsevier B.V. All rights reserved.

The effect of degradation and settlement on transport properties of mechanically and biologically treated (MBT) waste was examined by applying three different tracers to two waste columns (~0.5 m diameter) in a series of closed-loop experiments. One column was allowed to biodegrade and the other was bio-suppressed. Permeability and drainable porosity were reduced by settlement, in line with previous results. A dual-porosity model performed well against the data and suggested that more preferential flow occurred early on in the un-degraded column. Diffusion timescales were found to be between 0.8 and 6 days. Volumetric water contents of the mobile region were found to be small in the bio-suppressed cell (~0.01) and even smaller values were found in the degrading waste, possibly due to displacement by gas. Once either settlement or gas production had disrupted this pattern into a more even flow, subsequent compression made little difference to the diffusion time-scale. This may indicate that transport was thereafter dominated by other aspects of the waste structure such as the distribution of low-permeability objects. The presence of gas in the degrading waste reduced the volumetric water content through displacement. The model indicated that the gas was primarily located in the more mobile porosity fraction. Primary compression of the degrading waste tended to squeeze this gas out of the waste in preference to water.

The ingress of particulate material into freshwater spawning substrates is thought to be contributing to the declining success of salmonids reported over recent years for many rivers. Accordingly, the need for reliable information on the key sources of the sediment problem has progressed up the management agenda. Whilst previous work has focussed on apportioning the sources of minerogenic fine sediment degrading spawning habitats, there remains a need to develop procedures for generating corresponding information for the potentially harmful sediment-bound organic matter that represents an overlooked component of interstitial sediment. A source tracing procedure based on composite signatures combining bulk stable 13C and 15N isotope values with organic molecular structures detected using near infrared (NIR) reflectance spectroscopy was therefore used to assess the primary sources of sediment-bound organic matter sampled from artificial spawning redds. Composite signatures were selected using a combination of the Kruskal–Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were collected using time-integrating basket traps which were inserted at the start of the salmonid spawning season and extracted in conjunction with critical phases of fish development (eyeing, hatch, emergence, late spawning). Over the duration of these four basket extractions, the overall relative frequency-weighted average median (± 95% confidence limits) source contributions to the interstitial sediment-bound organic matter were estimated to be in the order: instream decaying vegetation (39 ± < 1%; full range 0–77%); damaged road verges (28 ± < 1%; full range 0–77%); septic tanks (22 ± < 1%; full range 0–50%), and; farm yard manures/slurries (11 ± < 1%; full range 0–61%). The reported procedure provides a promising basis for understanding the key sources of interstitial sediment-bound organic matter and can be applied alongside apportionment for the minerogenic component of fine-grained sediment ingressing the benthos. The findings suggest that human septic waste contributes to the interstitial fines ingressing salmonid spawning habitat in the study area.