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

In this study, a multifaceted approach for selecting the suitable candidates for bioaugmentation of activated sludge (AS) that supports leachate treatment was used. To determine the exploitation of 10 bacterial strains isolated from the various matrices for inoculating the AS contaminated with the Kalina pond leachate (KPL), their degradative potential was analyzed along with their aptitude to synthesize compounds improving remediation of pollutants in wastewater and ability to incorporate into the AS flocs. Based on their capability to degrade aromatic compounds (primarily catechol, phenol, and cresols) at a concentration of 1 mg/mL and survive in 12.5% of the KPL, Pseudomonas putida OR45a and P. putida KB3 can be considered to be the best candidates for bioaugmentation of the AS among all of the bacteria tested. Genomic analyses of these two strains revealed the presence of the genes encoding enzymes related to the metabolism of aromatic compounds. Additionally, both microorganisms exhibited a high hydrophobic propensity (above 50%) and an ability to produce biosurfactants as well as high resistance to ammonium (above 600 µg/mL) and heavy metals (especially chromium). These properties enable the exploitation of both bacterial strains in the bioremediation of the AS contaminated with the KPL.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selecting Bacteria Candidates for the Bioaugmentation of Activated Sludge to Improve the Aerobic Treatment of Landfill Leachate

Michalska

Piński

Żur

et al. 2020

“…Our data demonstrate that the myco-based process was capable of significantly reducing the clastogenic effects of the LFLs. Chemical, ecotoxicological, and microbiological characteristics of LFLs should be evaluated to assess the environmental risks posed by landfill emissions, because of the evidence that landfill leachates contain an unknown number of xenobiotic organic compounds, which constitute a potential risk to the quality of surface/ground waters, when released into the environment [30,54,55]. There is still a limited database, and an urgent need, for more information about these contaminants with respect to both their identity and concentrations, as well as to their toxicity.…”

Section: Discussionmentioning

confidence: 99%

Mycoremediation of Old and Intermediate Landfill Leachates with an Ascomycete Fungal Isolate, Lambertella sp.

Siracusa

Yuan

Chicca

et al. 2020

In the present study, an Ascomycete fungal strain, Lambertella sp., isolated from environmental polluted matrices, was tested for the capacity to reduce the contamination and the toxicity of intermediate and old landfill leachates. Batch tests in flasks, under co-metabolic conditions, were performed with two different old leachates, with suspended and immobilized Lambertella sp. biomass, resulting in a soluble chemical oxygen demand depletion of 70% and 45%, after 13 and 30 days, respectively. An intermediate landfill leachate was treated in lab-scale reactors operating in continuous conditions for three months, inoculated with immobilized Lambertella sp. biomass, in absence of co-substrates. The Lambertella sp. depleted the corresponding total organic carbon by 90.2%. The exploitability of the Lambertella sp. strain was evaluated also in terms of reduction of phyto-, cyto-, and mutagenicity of the different Landfill Leachates at the end of the myco-based treatment, resulting in an efficient depletion of leachate clastogenicity.

“…There are scarce data in the literature regarding the analysis of cytotoxicity of SS filtrates, but available data regarding cytotoxicity of landfill leachate enable us to apply similar methods. The use of in vitro models in the analysis of toxicity of different environmental matrices, such as sewage sludge, is more recent, but growing interest in this field has been observed [32]. Selected human cellular models represent human organs, which could be potentially damaged by xenobiotics exposure.…”

Section: Discussionmentioning

confidence: 99%

The Comparison of Selected Types of Municipal Sewage Sludge Filtrates Toxicity in Different Biological Models: From Bacterial Strains to Mammalian Cells. Preliminary Study

Jabłońska-Trypuć

Wydro

Serra-Majem

et al. 2019

Sewage sludge (SS) is a complex mixture of potentially toxic compounds, which may affect the environment. Many methodologies are being implemented in order to assess the risk that SS may cause after the exposition, but usually they rely on chemical analyses that cannot predict their toxicological impact. Therefore, biological systems are essential in such studies. The aim of this study was to estimate the effect of 3 types of SS filtrates: sludge from primary clarifier, sludge from aeration tank and sludge from thickened sludge tank after flocculant addition. In order to thoroughly investigate SS cytotoxicity, we proposed different biological models: Aliivibrio fischeri, Escherichia coli, Candida albicans and LN-229 glioblastoma cell line. Obtained results indicate that SS3 was the most toxic against A. fisheri, but tests conducted with the use of E. coli and LN-229 human cell line showed the higher toxicity of SS1. Different toxicity of analyzed filtrates in different biological models could be explained by differences in applied model structure, metabolism and life requirements. Therefore, the reuse of SS should be conducted with caution, and it is important for the SS to undergo a specific remediation process before introducing them into the environment.