Plastics in biogenic matrices intended for reuse in agriculture and the potential contribution to soil accumulation.

The spread of biogenic matrices for agricultural purposes can lead to plastic input into soils, raising a question on possible consequences for the environment. Nonetheless, the current knowledge concerning the presence of plastics in biogenic matrices is very poor. Therefore, the objective of the present study was a quali-quantitative characterization of plastics in different matrices reused in agriculture as manures, digestate, compost and sewage sludges. Plastics were quantified and characterized using a Fourier Transform Infrared Spectroscopy coupled with an optical microscope (µFT-IR) in Attenuated Total Reflectance mode. Our study showed the presence of plastics in all the investigated samples, albeit with differences in the content among the matrices. We measured a lower presence in animal matrices (0.06-0.08 plastics/g wet weight w.w.), while 3.14-5.07 plastics/g w.w. were measured in sewage sludges. Fibres were the prevalent shape and plastic debris were mostly in the micrometric size. The most abundant polymers were polyester (PEST), polypropylene (PP) and polyethylene (PE). The worst case was observed in the compost sample, where 986 plastics/g w.w. were detected. The majority of these plastics were compostable and biodegradable, with only 8% consisting of fragments of PEST and PE. Our results highlighted the need to thoroughly evaluate the contribution of reused matrices in agriculture to the plastic accumulation in the soil system.

To spread or not to spread? Assessing the suitability of sewage sludge and other biogenic wastes for agriculture reuse.

Sewage sludge (biosolids) management represents a worldwide issue. Due to its valuable properties, approximately one half of the EU production is recovered in agriculture. Nevertheless, growing attention is given to potential negative effects deriving from the presence of harmful pollutants. It is recognized that a (even very detailed) chemical characterization is not able to predict ecotoxicity of a mixture. However, this can be directly measured by bioassays. Actually, the choice of the most suitable tests is still under debate. This paper presents a multilevel characterization protocol of sewage sludge and other organic residues, based on bioassays and chemical-physical-microbiological analyses. The detailed description of the experimental procedure includes all the involved steps: the criteria for selecting the organic matrices to be tested and compared; the sample pre-treatment required before the analyses execution; the chemical, physical and microbiological characterisation; the bioassays, grouped in three classes (baseline toxicity; specific mode of action; reactive mode of action); data processing. The novelty of this paper lies in the integrated use of advanced tools, and is based on three pillars:•the direct ecosafety assessment of the matrices to be reused.•the adoption of innovative bioassays and analytical procedures.•the original criteria for data normalization and processing.

Wastewater toxicity removal: Integrated chemical and effect-based monitoring of full-scale conventional activated sludge and membrane bioreactor plants.

The literature is currently lacking effect-based monitoring studies targeted at evaluating the performance of full-scale membrane bioreactor plants. In this research, a monitoring campaign was performed at a full-scale wastewater treatment facility with two parallel lines (traditional activated sludge and membrane bioreactor). Beside the standard parameters (COD, nitrogen, phosphorus, and metals), 6 polynuclear aromatic hydrocarbons, 29 insecticides, 2 herbicides, and 3 endocrine disrupting compounds were measured. A multi-tiered battery of bioassays complemented the investigation, targeting different toxic modes of action and employing various biological systems (uni/multicellular, prokaryotes/eukaryotes, trophic level occupation). A traffic light scoring approach was proposed to quickly visualize the impact of treatment on overall toxicity that occurred after the exposure to raw and concentrated wastewater. Analysis of the effluents of the CAS and MBR lines show very good performance of the two systems for removal of organic micropollutants and metals. The most noticeable differences between CAS and MBR occurred in the concentration of suspended solids; chemical analyses did not show major differences. On the other hand, bioassays demonstrated better performance for the MBR. Both treatment lines complied with the Italian law's "ecotoxicity standard for effluent discharge in surface water". Yet, residual biological activity was still detected, demonstrating the adequacy and sensitivity of the toxicological tools, which, by their inherent nature, allow the overall effects of complex mixtures to be taken into account.

Improving the quality of wastewater treatment plant monitoring by adopting proper sampling strategies and data processing criteria.

Monitoring is a crucial operation for plant management. However, proper sampling procedures and data processing criteria are not always adopted. Wastewater treatment plants work under dynamic conditions, which poses a challenge for a correct performance assessment. The aim of this work is to analyse some important aspects of wastewater sampling and data processing, to identify case by case methods which should to be adopted in order to obtain reliable and consistent information on plant performance. The study was conducted through simulations and real data analyses. It turned out that: a) the preferable 24-hour composite sampling procedure is the flow-proportional mode; in addition, the required sampling frequency (i.e. the number of sub-samples to be taken to make the 24-h composite sample) increases as the percentage of population discontinuously discharging the monitored substance decreases; b) a Variability Index was defined to help find the minimum sampling frequency (i.e. the number of 24-h composite samples per year) for the calculation of annual mass flows with an acceptable uncertainty; and c) criteria were proposed for the identification of pseudo-steady state periods needed to calculate reliable mass balances and plant performance indicators.

Environmental Footprint of Wastewater Treatment: A Step Forward in the Use of Toxicological Tools.

The assessment of the actual impact of discharged wastewater on the whole ecosystem and, in turn, on human health requires the execution of bioassays. In effect, based on the chemical characterization alone, the synergistic/antagonistic effect of mixtures of pollutants is hardly estimable. The aim of this work was to evaluate the applicability of a battery of bioassays and to suggest a smart procedure for results representation. Two real wastewater treatment plants were submitted to analytical campaigns. Several baseline toxicity assays were conducted, together with tests for the determination of endocrine activity, genetic toxicity and carcinogenicity of wastewater. A "traffic light" model was adopted for an easy-to-understand visualization of the results. Although the legal prescriptions of chemical parameters are fully complied with, bioassays show that a certain biological activity still residues in the treated effluents. Moreover, influent and effluent responses are not always appreciably different. Some tests employing human cells were revealed to be only partially adequate for environmental applications. An interesting and helpful development of the present approach would consist in the estimation of biological equivalents of toxicity, as shown for the estrogenic compound 17-ß-estradiol.

Genotoxic Activity of Particulate Matter and In Vivo Tests in Children Exposed to Air Pollution.

The aim of this paper was to investigate the relationship between micronuclei and DNA damage in children's buccal mucosa cells and the genotoxicity and mutagenicity of the different sized fractions of particulate matter as well as the concentration of PAHs (polycyclic aromatic hydrocarbons) and metals in particulate matter. Air particulate matter was collected by high volume samplers located near the schools attended by the children on the same days of biological samplings. The mutagenic activity was assessed in different cells in in vitro tests (Ames test on bacteria and comet test on leukocytes). Our study showed weak positive correlations between (a) the mutagenicity of the PM0.5 fraction and PAHs and (b) the micronuclei test of children's buccal cells and PAHs detected in PM0.5 and PM0.5-3 fractions. A positive correlation was also found between in vitro comet test on leukocytes and PAHs in the PM3-10 fraction. No correlation was observed for metal concentrations in each PM fraction.

Can particulate matter be identified as the primary cause of the rapid spread of CoViD-19 in some areas of Northern Italy?

Northern Italy was the most affected by CoViD-19 compared to other Italian areas and comprises zones where air pollutants concentration was higher than in the rest of Italy. The aim of the research is to determine if particulate matter (PM) has been the primary cause of the high CoViD-19 spread rapidity in some areas of Northern Italy. Data of PM for all the 41 studied cities were collected from the local environmental protection agencies. To compare air quality data with epidemiological data, a statistical analysis was conducted identifying the correlation matrices of Pearson and Spearman, considering also the possible incubation period of the disease. Moreover, a model for the evaluation of the epidemic risk, already proposed in literature, was used to evaluate a possible influence of PM on CoViD-19 spread rapidity. The results exclude that PM alone was the primary cause of the high CoVid-19 spread rapidity in some areas of Northern Italy. Further developments are necessary for a better comprehension of the influence of atmospheric pollution parameters on the rapidity of spread of the virus SARS-CoV-2, since a synergistic action with other factors (such as meteorological, socio-economic and cultural factors) could not be excluded by the present study.

Analysis of lockdown for CoViD-19 impact on NO2 in London, Milan and Paris: What lesson can be learnt?

Nitrogen dioxide (NO2) can have harmful effects on human health and can act as a precursor for the formation of other air pollutants in urban environment such as secondary PM2.5 and ozone. The lockdown measures for CoViD-19 allowed to simulate on a large scale the massive and prolonged reduction of road traffic (the main source for NO2 in urban environment). This work aims to selectively assess the maximum impact that total traffic blocking measures can have on NO2. For this reason, three megacities (London, Milan and Paris) were chosen which had similar characteristics in terms of climatic conditions, population, policies of urban traffic management and lockdown measures. 52 air quality control units have been used to compare data measured in lockdown and in the same periods of previous years, highlighting a significant decrease in NO2 concentration due to traffic (London: 71.1 % - 80.8 %; Milan: 8.6 % - 42.4 %; Paris: 65.7 % - 79.8 %). In 2020 the contribution of traffic in London, Milan and Paris dropped to 3.3 ± 1.3 µg m-3, 6.1 ± 0.8 µg m-3, and 13.4 ± 1.5 µg m-3, respectively. Despite the significant reduction in the NO2 concentration, in UT stations average NO2 concentrations higher than 40 µg m-3 were registered for several days. In order to reduce the pollution, the limitation of road traffic could be not enough, but a vision also aimed at rethink the vehicles and their polluting effects should be developed.

SARS-CoV-2 in sewer systems and connected facilities.

As for the SARS coronavirus in the 2003 epidemic, the presence of SARS-CoV-2 has been demonstrated in faeces and, in some cases, urine of infected people, as well as in wastewater. This paper proposes a critical review of the state of the art regarding studies on the presence of SARS-CoV-2 in wastewater and sewage sludge, the factors affecting its inactivation and the main proposed treatments. In-vitro tests demonstrated low resistance of SARS-CoV-2 to high temperature, while even significant changes in pH would not seem to determine the disappearance of the virus. In real wastewater and in sewage sludge, to date studies on the influence of the different parameters on the inactivation of SARS-CoV-2 are not available. Therefore, studies involving other HCoVs such as SARS-CoV and HCoV-229E have been also considered, in order to formulate a hypothesis regarding its behaviour in sewage and throughout the steps of biological treatments in WWTPs. Finally, SARS-CoV-2 in wastewater might track the epidemic trends: although being extremely promising, an effective and wide application of this approach requires a deeper knowledge of the amounts of viruses excreted through the faeces and the actual detectability of viral RNA in sewage.

Long-term investigation on the removal of perfluoroalkyl substances in a full-scale drinking water treatment plant in the Veneto Region, Italy.

Drinking water contamination by perfluoroalkyl and polyfluoroalkyl substances (PFASs) is an issue of relatively recent concern. The literature indicates that anion exchange resins and granular activated carbon (GAC) are suitable technologies for removing these compounds. While several laboratory-scale and pilot-scale experiments have been conducted to study activated carbon adsorption/desorption mechanisms of a number of PFASs, little data on full-scale plants are available. This work examines a real case of groundwater contamination by PFASs in an area of approximately 200 km2. The performance of the main drinking water treatment plant in the area (flowrate = 30,000 m3/d; 100,000 people served), which is equipped with GAC filters, was analysed. Approximately 17,000 analytical data points from a working period of five years were processed. Perfluorobutyric acid (PFBA) was the first compound to attain breakthrough, followed by perfluoropentanoic acid, perfluorohexanoic acid, perfluorobutanesulfonic acid, and perfluorooctanoic acid (PFOA). The adsorption capacity and treated bed volumes at complete breakthrough (saturation) were calculated, and ranged from 1.71 g/t and 7100 (PFBA) to 24.6 g/t and 50,900 (PFOA), with the total organic carbon concentration in the groundwater ranging from <0.1 to 0.5 mg/L. The overall adsorption capacity was approximately 40 g of total PFASs/t. The breakthrough behaviour of PFASs was correlated with the CF chain length, the type of hydrophilic head (either carboxyl or sulfonic), and the n-octanol/water partition coefficients logP and logD. The results corroborate the findings of previously published bench-scale and pilot-scale experiments.

Lockdown for CoViD-2019 in Milan: What are the effects on air quality?

Based on the rapid spread of the CoViD-2019, a lockdown was declared in the whole Northern Italy by the Government. The application of increasingly rigorous containment measures allowed to reduce the impact of the CoViD-2019 pandemic on the Italian National Health System but at the same time these restriction measures gave also the opportunity to assess the effect of anthropogenic activities on air pollutants in an unprecedented way. This paper aims to study the impact of the partial and total lockdown (PL and TL, respectively) on air quality in the Metropolitan City of Milan. As results, the severe limitation of people movements following the PL and the subsequent TL determined a significant reduction of pollutants concentration mainly due to vehicular traffic (PM10, PM2.5, BC, benzene, CO, and NOx). The lockdown led to an appreciable drop in SO2 only in the city of Milan while it remained unchanged in the adjacent areas. Despite the significant decrease in NO2 in the TL, the O3 exhibited a significant increase, probably, due to the minor NO concentration. In Milan and SaA the increase was more accentuated, probably, due to the higher average concentrations of benzene in Milan than the adjacent areas that might have promoted the formation of O3 in a more significant way.

Promoting biological phosphorus removal in a full scale pre-denitrification wastewater treatment plant.

A survey conducted in Italy revealed that less than 0.5% out of a sample of over 2,000 municipal wastewater treatment plants is equipped with an enhanced biological phosphorus removal process. Conditions promoting biological phosphorus removal have been investigated by monitoring three real plants equipped with, respectively: (A) simultaneous chemical precipitation; (B) enhanced biological removal powered by chemical precipitation; (C) tertiary chemical precipitation with evidence of phosphate accumulating bacteria. An anaerobic compartment revealed essential for the growth of these microorganisms, the readily degradable organic concentration in the influent playing a minor role. Mapping dissolved oxygen and oxidation-reduction potential in different compartments of plant (C) was carried out to understand the reasons why phosphate accumulating bacteria were found even in the absence of anaerobic reactor. Finally, the possibility to exploit the biological phosphorus removal in plant (C), by adjusting the aeration conditions, was explored and an economic analysis showed this to be a preferable approach with respect to the chemical removal of phosphorus.

"Risk is in the air": Polycyclic aromatic hydrocarbons, metals and mutagenicity of atmospheric particulate matter in a town of Northern Italy (Respira study).

Air pollution has well-known harmful effects on human beings, causing both acute and chronic diseases. Some data suggest that genetic damage occurring early in life may influence the risk of having cancer and other chronic diseases in adulthood. Therefore, there is a growing interest in studying the genotoxic activity of air pollution, and especially particulate matter. The aim of this study was to analyze airborne particulate matter (PM10) collected in an industrialized town of Northern Italy. PM10 was sampled in six areas of the town, divided in three distinct dimensional classes (<0.5 µm; 0.5-3 µm and 3-10 µm), and analyzed for the quantification of polynuclear aromatic hydrocarbons and metals contents. A model-based approach using diagnostic ratios and toxic equivalency factor was also followed. Concurrently, biological assays were performed for the assessment of mutagenicity and genotoxicity in bacteria, human and plant cells. Mutagenicity was observed in bacteria and human cells, with a clear dose-response relationship, induced above all by the finest PM samples (PM0.5 and PM0.5-3), which contained the largest number of polycyclic aromatic hydrocarbons. DNA damage, such as chromosomal aberrations and micronuclei, was also found in Allium cepa root cells, but without a clear relationship with the tested doses. The in-vitro models utilized showed to be good indicators of air quality for mutagenicity. Chemical analyses evidenced high content of polycyclic aromatic hydrocarbons, metals and semi-metals in PM extracts. Polycyclic aromatic hydrocarbons, metals and mutagenicity can be ascribed mainly to vehicular traffic (in terms of both exhausted gases emission and mechanical losses), which represents a constant and ubiquitous source of human exposure, and to steel working, carried out within the urban area.

The role of bioassays in the evaluation of ecotoxicological aspects within the PEF/OEF protocols: The case of WWTPs.

The suitability evaluation of any industrial process should rely on economic, technical, social and, in particular, environmental aspects. The Commission Recommendation 2013/179/UE enables the improvement and the harmonization of the conventional evaluation of environmental footprints, such as LCA (Life Cycle Assessment), Carbon and Water Footprint, by suggesting the assessment of life cycle environmental performance of products and organisations (PEF, OEF). Novelty aspects reside in including new impact categories (namely, human toxicity cancer effects, human toxicity not-cancer effects and eco-toxicity). This paper presents an application of PEF/OEF protocol to the example case of an activated sludge wastewater treatment plant. Strengths and criticisms of this approach are discussed, by taking into consideration the possible final goal of the suitability assessment. Valuably, the adoption of bioassays (i.e., the input of their results in the models for calculating the life cycle environmental performance) for a more reliable evaluation of the impact on the ecosystem and human health is proposed.

Suitability of Sludge Biotic Index (SBI), Sludge Index (SI) and filamentous bacteria analysis for assessing activated sludge process performance: the case of piggery slaughterhouse wastewater.

Piggery slaughterhouse wastewater poses serious issues in terms of disposal feasibility and environmental impact, due to its huge organic load and variability. It is commonly treated by means of activated sludge processes, whose performance, in case of municipal wastewater, can be monitored by means of specific analyses, such as Sludge Biotic Index (SBI), Sludge Index (SI) and floc and filamentous bacteria observation. Therefore, this paper was aimed at assessing the applicability of these techniques to piggery slaughterhouse sewage. A plant located in Northern Italy was monitored for 1 year. Physical, chemical and operation parameters were measured; the activated sludge community (ciliates, flagellates, amoebae and small metazoa) was analysed for calculating SBI and SI. Floc and filamentous bacteria were examined and described accordingly with internationally adopted criteria. The results showed the full applicability of the studied techniques for optimizing the operation of a piggery slaughterhouse wastewater treatment plant.

Municipal wastewater affects adipose deposition in male mice and increases 3T3-L1 cell differentiation.

Trace concentration of EDs (endocrine disrupting compounds) in water bodies caused by wastewater treatment plant effluents is a recognized problem for the health of aquatic organisms and their potential to affect human health. In this paper we show that continuous exposure of male mice from early development to the adult life (140 days) to unrestricted drinking of wastewater collected from a municipal sewage treatment plant, is associated with an increased adipose deposition and weight gain during adulthood because of altered body homeostasis. In parallel, bisphenol A (BPA) at the administration dose of 5 µg/kg/body weight, shows an increasing effect on total body weight and fat mass. In vitro, a solid phase extract (SPE) of the wastewater (eTW), caused stimulation of 3T3-L1 adipocyte differentiation at dilutions of 0.4 and 1 % in the final culture medium which contained a concentration of BPA of 40 nM and 90 nM respectively. Pure BPA also promoted adipocytes differentiation at the concentration of 50 and 80 µM. BPA effect in 3T3-L1 cells was associated to the specific activation of the estrogen receptor alpha (ERα) in undifferentiated cells and the estrogen receptor beta (ERß) in differentiated cells. BPA also activated the Peroxisome Proliferator Activated Receptor gamma (PPARγ) upregulating a minimal 3XPPARE luciferase reporter and the PPARγ-target promoter of the aP2 gene in adipose cells, while it was not effective in preadipocytes. The pure estrogen receptor agonist diethylstilbestrol (DES) played an opposite action to that of BPA inhibiting PPARγ activity in adipocytes, preventing cell differentiation, activating ERα in preadipocytes and inhibiting ERα and ERß regulation in adipocytes. The results of this work show that the drinking of chemically-contaminated wastewater promotes fat deposition in male mice and that EDs present in sewage are likely responsible for this effect through a nuclear receptor-mediated mechanism.

The assessment of WWTP performance: Towards a jigsaw puzzle evaluation?

A chemical and bio-analytical protocol is proposed as a holistic monitoring framework for the assessment of WWTPs (Wastewater Treatment Plants) performance. This combination of tests consists of: i) an analysis of emerging contaminants, to be added to the established physico-chemical parameters in order to understand the causes of (new) pollution phenomena and ii) some of the bio-analytical tools most widely applied in the field of wastewater research, which provide information on groups of chemicals with a common mode of toxic action (baseline toxicity, estrogenicity and mutagenicity/genotoxicity, selected as the most representative for human health). The negative effects of the discharge can thus be highlighted directly and used to assess the global environmental impact of WWTPs. As a validation, this multi-tiered approach was applied to a full-scale WWTP (150,000 p.e.), where different measurements were carried out: EDCs (Endocrine Disrupting Compounds) detection; algal growth inhibition, bioluminescence inhibition and acute toxicity test (for baseline toxicity); an E-Screen-like assay (for estrogenic activity); Ames, Allium cepa and Comet tests (for mutagenic/genotoxic activity). As a result, the WWTP showed good performance for all these issues, displaying its ability to enhance effluent quality, except for residual mutagenic behaviour, probably due to the by-products generated by the tertiary ozonation.