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Airport de-icing has been linked with the growth of undesirable river biofilms (URBs, formerly “sewage fungus”), a manifestation of organic pollution causing long-term ecological damage to watercourses. URBs are a polymicrobial community, with one key taxon standing out in literature: Sphaerotilus natans, a filamentous bacterium also found in sewage treatment and activated sludges. An industry often implicated in causing URBs is airport de-icing, with large biofilms often developing downstream of airport discharges in winter months. However, it is not yet clear which de-icers may cause URBs and how they influence growth. Therefore, specific objectives were to (i) determine which freeze-point depressants (FPDs) can be utilized by S. natans; (ii) examine differences in the growth kinetics between FPDs; and (iii) compare pure-FPDs to commercial airport de-icers (CADs) as carbon sources, to determine impacts of additives. This study employed a turbidimetric micro-batch culture design to conduct microbial growth experiments, using S. natans and a minimal medium supplemented with airport de-icer as the carbon source. Equimolar carbon concentrations were used to compare the effects of common FPDs and CADs – each containing a specific FPD. Growth was assessed via optical density (OD600) measurements, from which time-to-detection, maximum rate of change, and maximum optical density were derived and kinetics inferred. S. natans was found to grow effectively on all FPDs tested, although the microbial yield was heavily dependent on the carbon concentration for all FPDs and CADs. Sodium acetate generated the quickest growth, with the lowest TTD (lag-time) for all but the lowest concentrations tested. Propylene glycol produced the greatest maxOD (total growth), whereas ethylene glycol had a higher limiting concentration for maxROC (growth rate). The mixture of compounds and additives in commercial products did not significantly impact the growth of S. natans. This research provides evidence from controlled laboratory experiments that airport de-icers support the growth of S. natans. The differences in growth kinetics observed for the FPDs and CADs could inform improved mitigation or treatment to reduce the incidence and ecological impacts of URBs.

Prisons are high-risk settings for infectious disease transmission, due to their enclosed and semi-enclosed environments. The proximity between prisoners and staff, and the diversity of prisons reduces the effectiveness of non-pharmaceutical interventions, such as social distancing. Therefore, alternative health monitoring methods, such as wastewater-based epidemiology (WBE), are needed to track pathogens, including SARS-CoV-2. This pilot study assessed WBE to quantify SARS-CoV-2 prevalence in prison wastewater to determine its utility within a health protection system for residents. The study analysed 266 samples from six prisons in England over a 12-week period for nucleoprotein 1 (N1 gene) and envelope protein (E gene) using quantitative reverse transcriptase-polymerase chain reaction. Both gene assays successfully detected SARS-CoV-2 fragments in wastewater samples, with both genes significantly correlating with COVID-19 case numbers across the prisons (p < 0.01). However, in 25% of the SARS-positive samples, only one gene target was detected, suggesting that both genes be used to reduce false-negative results. No significant differences were observed between 14- and 2-h composite samples, although 2-h samples showed greater signal variance. Population normalisation did not improve correlations between the N1 and E genes and COVID-19 case data. Overall, WBE shows considerable promise for health protection in prison settings. HIGHLIGHTS Wastewater epidemiology is effective in flagging COVID-19 cases in prison settings.; SARS-CoV-2 levels were quantified using N1 and E gene targets.; Both targets should be used in routine analysis to reduce false negatives.; COVID-19 case numbers significantly correlated with both wastewater gene targets across all samples.; Each prison is different – local activities are important when designing sampling programmes.;

Sewage fungus is a classic bioindicator of organic pollution in streams and rivers. However, it has received limited scientific interest in recent decades, despite persistent occurrence in lotic ecosystems. The aim of this review is to provide an up-to-date assessment of sewage fungus, its composition and structure, and the environmental factors that influence its growth to support future research and mitigation interventions. We advocate for the term “undesirable river biofilm” (URB) to more accurately characterise the composition, location, and environmental consequences of sewage fungus. These filamentous or gelatinous growths found on the banks and beds of flowing watercourses are composed predominantly of bacteria, not fungi. Based on modern genomic analyses, we now know that URBs are composed of a diversity of microbial taxa, including those that have long been associated with sewage fungus (e.g. Sphaerotilus, Beggiatoa, and Zoogloea) and newer associated taxa (e.g. Rhodoferax and Thiothrix). While organic pollution is generally considered the main trigger, this review highlights the importance of other environmental factors, such as water velocity, river substrate, pollutant composition and loading, and shading, in the occurrence and persistence of URBs. To illustrate the widespread and continued presence of URBs in rivers, environmental surveillance data for England's rivers were analysed. Between 2000 and 2020, environment officers documented 6,025 occurrences of URBs as part of a wider water quality incident reporting programme. Thus, URBs persist even in countries with stringent water quality standards and comprehensive wastewater infrastructure, suggesting they may continue to be a significant issue globally, despite limited public or scientific focus. We argue that in addition to tackling point discharge of organic pollutants, greater emphasis should be placed on understanding the impact of intermittent and diffuse pollution and altered environmental conditions on river ecosystems. To safeguard river ecosystems, a holistic approach is needed that considers pollution in combination with wider river functioning (e.g. river hydrology, geomorphology, biogeochemical processing, and riparian zones) and climate change. Future areas for study into the URB phenomenon are suggested, including more comprehensive monitoring of URBs specifically and river biofilm health generally.

The widespread use of glyphosate has significantly increased its presence in drinking water sources. Aminomethylphosphonic Acid (AMPA), a breakdown product of glyphosate, is challenging to remove from water using conventional treatment methods, posing risks to public health and environmental safety. This work investigates the biodegradation of AMPA by bacteria isolated from three environmental sources, with a focus on determining their potential application in water treatment systems. Two samples were collected from granular activated carbon (GAC) filters of different operational durations at a water treatment facility, and one sample was taken from soil that had historically been treated with glyphosate-based herbicides. Bacterial isolates capable of degrading AMPA were identified from these samples through selective enrichment, and kinetic degradation experiments were then conducted to assess their effectiveness. In environmental samples, after 48 hrs AMPA removal was > 70 % using GAC from an active treatment plant and soil samples removed 19 %. After bacterial isolation a consortium was isolated and from these four isolates were identified, comprising three species, including novel AMPA degraders M−S3 and M−SS (Myroides sp. mNGS23), and P-S92 (Pseudochrobactrum saccharolyticum). Within both minimal media supplemented with AMPA and raw untreated showing substrate concentrations above 10 mg/L whilst the specific degradation rates saw a decrease in substrate concentrations above 100 mg/L. AMPA removal occured in pilot scale sand filters augmented with P-S92 but removal was inconsistent. These findings show the potential of using biodegradation as an effective treatment strategy for AMPA removal from water. The identification of AMPA-degrading bacteria offers a promising solution for enhancing the removal of this persistent pollutant from contaminated waters. Further research is recommended to explore the full-scale application of these isolates in water treatment processes. This study contributes to the development of sustainable water treatment technologies by harnessing the natural degradative capacities of environmental bacteria.