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Title: Physicochemistry and toxicity of landfill leachates and particulate matter
Author: Koshy, Lata
ISNI:       0000 0004 2748 5167
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2009
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An understanding of the ranges of toxicity of landfill emissions is crucial in determining the degree of concern we should have about the potential effects they could have upon nearby populations and the surrounding environment. Landfill leachates and airborne PM10 were collected and assessed for their transition metal-mediated in vitro bioreactivity by a plasmid DNA scission assay (PSA). Human tissue equivalents (EpiDerm -200 and EpiAirway -100 MatTek Corp., USA) were exposed to landfill leachate or PM10 and evaluated for cell viability (MTT assay) and trans-epithelial electrical resistance (TEER). The novel use of the oxidant-sensitive probe, DCFH, with landfill leachates was a good indication of leachate ROS activity. The results also revealed that leachate bioreactivity varied inter- and intra-landfills it was not possible to establish an easily elucidated trend associated with most commonly measured physical parameters (data kindly provided by landfill operators). Metal chelation by EDTA, DTPA, DES and Chelex resin caused significant attenuation of landfill leachate oxidant activity in both the PSA and DCFH assays. Acute leachate toxicity, gauged by a bacterial V. fischeri bioluminescence assay (ROTAS), revealed temporal-dependant hormetic responses from the bacteria which corresponded to high levels of TDS, conductivity and redox potential. Undiluted leachates were not acutely cytotoxic to EpiDerm -200 following 24h exposure. PM10 was collected from a Cardiff landfill and characterised by FESEM-EDX, ICP-MS and IC. The landfill PM10 physicochemistry varied year-on-year, and was dependent upon anthropogenic site activity. Metal chelation by EDTA, DTPA, DES and surrogate epithelial lining fluid caused significant attenuation of landfill PM10 oxidant activity in the PSA this was comparable to Cardiff urban PM10 reactivity. The PM2 5-01 soluble fraction was the most oxidant component. Landfill PM10 (500ug/ml) was not cytotoxic to EpiAirway -100 following 24h exposure. Preliminary toxicogenomics suggested several chaperones and heat shock proteins were up-regulated by landfill PM10. However, human disease causality was not confirmed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available