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

Abstract

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.

Potential toxicity of leachate from the municipal landfill in view of the possibility of their migration to the environment through infiltration into groundwater

“…Twofold dilution series of LL were prepared according to Jabłońska-Trypuć et al ( 2019a ). The final concentrations of LL in each well were 50%, 25%, 12.5%, 6.25%, 3.13%, 1.56%, 0.78%, 0.39%, 0.20% and 0.10%.…”

Human Cell Culture, a Pertinent In Vitro Model to Evaluate the Toxicity of Landfill Leachate/Sewage Sludge. A Review

“…Other cell lines very commonly used in LL and SS cytotoxicity studies are the human HOS osteosarcoma line, Jurkat lymphoma cells, CHO line, LN229 glioblastoma and mouse fibroblast line NIH/3T3 [71][72][73][74].…”

“…In Table 1, different human cell lines and tests are compiled with obtained results. MTT assay, alkaline comet assay HepG2 EC50 value ranging from 11.58 to 20.44% [75] fluorescence microscopy (acridine orange/ethidium bromide) lymphocytes cytotoxic effect of raw leachate; treated samples showed no cytotoxic effect [76] MTT assay cell scratch damage MCF-7 Phenols extracts from landfill leachate could slow down the rate of migration of cells [63] MTT assay LN-229 no cytotoxic activity of sewage sludge filtrates [71] comet assay NHDF (normal human dermal fibroblasts), Me45 decrease in LL toxicity after treatment [53] MTT assay CellTiter-Glo™ 2.0 Assay A-375 fibroblasts landfill leachate cytotoxic to fibroblasts, no cytotoxic effect in A-375 [23] MTT assay A-375 fibroblasts sewage sludge cytotoxic to fibroblasts, no cytotoxic effect in A-375 [67]…”

Strength and microstructure properties of solidified sewage sludge with two types of cement-based binders

“…In addition, some SS may also contain toxic and hazardous pollutants including microorganism, pathogen and heavy metals that may pollute the environment 4 . The safe disposal of SS has become an important issue affecting sustainable environmental management [5][6][7][8][9] . As an effective method, the solidification/stabilization treatment by mixing into a binder is widely used in the world to realize the resource utilization of SS [10][11][12] .…”