Investigating landfill leachate toxicity in vitro: A review of cell models and endpoints

Landfill leachate is a complex mixture characterized by high toxicity and able to contaminate soils and waters surrounding the dumpsite, especially in developing countries where engineered landfills are still rare. Leachate pollution can severely damage natural ecosystems and harm human health. Traditionally, the hazard assessment of leachate is based on physicochemical characterization but the toxicity is not considered. In the last few decades, different bioassays have been used to assess the toxicity of this complex matrix, including human-related in vitro models. This article reviews the cell bioassays successfully used for the risk assessment of leachate and to evaluate the efficiency of toxicity removal of several processes for detoxification of this wastewater. Articles from 2003 to 2018 are covered, focusing mainly on studies that used human cell lines, highlighting the usefulness and adequacy of in vitro models for assessing the hazard involved with exposure to leachate, particularly as an integrative supporting tool for chemical-based risk assessment. Leachate is generally toxic, mutagenic, genotoxic and estrogenic in vitro, and these effects can be measured in the cells exposed to already low concentrations, confirming the serious hazard of this wastewater for human health. Keywords: Landfill leachate, In vitro models, Estrogenicity, Genotoxicity, Human cell line

ERICA: A multiparametric toxicological risk index for the assessment of environmental healthiness

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Abatement of the ecotoxicological risk of landfill leachate by heterogeneous Fenton-like oxidation

Landfill leachates are highly contaminated liquid waste, and their treatment and detoxification are a challenging task. The current system of ecotoxicological risk assessment is complex and time-consuming. It is of fundamental importance to develop simpler and faster tools for the evaluation of the treated liquid waste and for an easier preliminary screening of the most active catalytic formulation/reaction conditions of the Fenton-like process. Here, several analytical techniques have been used for the assessment of the reduction of toxicity of the landfill leachate after Fenton process over copper-zirconia catalyst (ZrCu). Ultraviolet-visible (UV-vis) spectroscopy and absorbable organic halogens (AOX) analysis have been coupled to achieve further insight into the degradation of contaminants. In addition, for the first time, the qualitative abatement of organic compounds is monitored through proton nuclear magnetic resonance (H-1 NMR) analysis, providing a new method for evaluating the effectiveness of the treatment. Spectroscopic techniques reveal that the Fenton process induces a significant abatement of the aromatic and halogen compounds (51%) in the landfill leachate with a reduction of the toxicity that has been confirmed by ecotoxicological test with algae. These results validate the investigated tool for a simple rapid preliminary evaluation of the detoxification efficacy

Digestate and Fugate – Fertilizers with Ecotoxicological Risks

Increasing number of decentralised biogas plants increases not only the amount of biogas produced, but also the production of digestate. Digestate and fugate are believed to be good fertilizers. However, there is often a tradeoff between other environmental impacts linked to agricultural production like eutrophication or ecotoxicity. Only limited ecotoxicological information is known about the effects of digestate or fugate on terrestrial fauna and flora. This is the first study comparing the survival and reproduction of collembolans as the representative soil fauna and the root growth and photosynthetic activity of Sinapis alba and Panicum miliaceum plants when exposed to digestate and fugate. Comparison of ecotoxicological results with chemical analysis of both digestate and fugate has led to the conclusions that application of digestate and fugate was beneficial neither for tested plants, nor for zooedaphon. Under practically used dosing both digestate and fugate can represent potential ecotoxicological problems, which can affect zooedaphon diversity and reproduction resulting in degradation of soil structure, reduction of microbial activity or water retention capacity of treated soils. That is why we do recommend at least simplified ecotoxicological testing of digestate as presented in this study. Ecotoxicity testing can support decision of direct application on soil, or mixing the digestate with other materials (like compost, manure, pond sediments, or biochar), what will help to utilize nutrients and consequently can prevent degradation of soil fertility

Pathogenic variants in the AFG3L2 proteolytic domain cause SCA28 through haploinsufficiency and proteostatic stress-driven OMA1 activation

Background: Spinocerebellar ataxia type 28 (SCA28) is a dominantly inherited neurodegenerative disease caused by pathogenic variants in AFG3L2. The AFG3L2 protein is a subunit of mitochondrial m-AAA complexes involved in protein quality control. Objective of this study was to determine the molecular mechanisms of SCA28, which has eluded characterisation to date. Methods: We derived SCA28 patient fibroblasts carrying different pathogenic variants in the AFG3L2 proteolytic domain (missense: the newly identified p.F664S and p.M666T, p.G671R, p.Y689H and a truncating frameshift p.L556fs) and analysed multiple aspects of mitochondrial physiology. As reference of residual m-AAA activity, we included SPAX5 patient fibroblasts with homozygous p.Y616C pathogenic variant, AFG3L2 +/\ue2 ' HEK293 T cells by CRISPR/Cas9-genome editing and Afg3l2 \ue2 '/\ue2 ' murine fibroblasts. Results: We found that SCA28 cells carrying missense changes have normal levels of assembled m-AAA complexes, while the cells with a truncating pathogenic variant had only half of this amount. We disclosed inefficient mitochondrial fusion in SCA28 cells caused by increased OPA1 processing operated by hyperactivated OMA1. Notably, we found altered mitochondrial proteostasis to be the trigger of OMA1 activation in SCA28 cells, with pharmacological attenuation of mitochondrial protein synthesis resulting in stabilised levels of OMA1 and OPA1 long forms, which rescued mitochondrial fusion efficiency. Secondary to altered mitochondrial morphology, mitochondrial calcium uptake resulted decreased in SCA28 cells. Conclusion: Our data identify the earliest events in SCA28 pathogenesis and open new perspectives for therapy. By identifying similar mitochondrial phenotypes between SCA28 cells and AFG3L2 +/- cells, our results support haploinsufficiency as the mechanism for the studied pathogenic variants

Phytotoxicity of wear debris from traditional and innovative brake pads

Traffic-related emissions include gas and particles that can alter air quality and affect human and environmental health. Limited studies have demonstrated that particulate debris thrown off from brakes are toxic to higher plants. The acute phytotoxicity of brake pad wear debris (BPWD) investigated using cress seeds grown in soil contaminated with increasing concentrations of debris. Two types of pads were used: a commercially available phenol based pad and an innovative cement-based pad developed within of the LIFE+ COBRA project. The results suggested that even through the BPWD generated by the two pads were similar in and morphology, debris from traditional pads were more phytotoxic than that from cementitious pads, causing significant alterations in terms of root elongation and loss of plasma membrane integrity

Bacterial load and inflammatory response in sputum of alpha-1 antitrypsin deficiency patients with COPD

Background: Airway inflammation may drive the progression of chronic obstructive pulmonary disease (COPD) associated with alpha-1 antitrypsin deficiency (AATD), but the relationship between airway microbiota and inflammation has not been investigated. Methods: We studied 21 non-treated AATD (AATD-noT) patients, 20 AATD-COPD patients under augmentation therapy (AATD-AT), 20 cigarette smoke-associated COPD patients, 20 control healthy smokers (CS) and 21 non-smokers (CON) with normal lung function. We quantified sputum inflammatory cells and inflammatory markers (IL-27, CCL3, CCL5, CXCL8, LTB4, MPO) by ELISA, total bacterial load (16S) and pathogenic bacteria by qRT-PCR. Results: AATD-AT patients were younger but had similar spirometric and DLCO values compared to cigarette smoke-associated COPD, despite a lower burden of smoking history. Compared to cigarette smoke-associated COPD, AATD-noT and AATD-AT patients had lower sputum neutrophil levels (p=0.0446, p=0.0135), total bacterial load (16S) (p=0.0081, p=0.0223), M. catarrhalis (p=0.0115, p=0.0127) and S. pneumoniae (p=0.0013, p=0.0001). Sputum IL-27 was significantly elevated in CS and cigarette smoke-associated COPD. AATD-AT, but not AATD-noT patients, had IL-27 sputum levels (pg/ml) significantly lower than COPD (p=0.0297) and these positively correlated with FEV1% predicted values (r=0.578, p=0.0307). Conclusions: Compared to cigarette smoke-associated COPD, AATD-AT (COPD) patients have a distinct airway inflammatory and microbiological profile. The decreased sputum bacterial load and IL-27 levels in AATD-AT patients suggests that augmentation therapy play a role in these changes