Abstract
M.Tech.
Background: Contaminated groundwater threatens many valuable water resources with potentially disastrous consequences. Because of the non-visible nature of groundwater, water testing methods are required that can detect not only the occurrence of dense non-aqueous phase liquids (DNAPL)-like substances in groundwater, but also address human health-related effects of the water upon consumption. Assuming ingestion of DNAPL-contaminated water may, depending on the concentration, mediate an inflammatory response or cause cellular injuries in the human body, like any other contaminant in water, which could compromise the immune response and cause numerous health problems. Hence the aim of the study was to develop and test methodologies from known immunological-testing techniques to establish whether DNAPL-contaminated drinking water would cause health-related effects.
Objectives: To develop a DNAPL reference model based on positive and baseline controls:(1) Using known concentrations of index chemical from each of two DNAPL groups i.e. trichloroethylene (TCE) from the chlorinated solvents (CS) and Aroclor®1254 (ARO) from polychlorinated biphenyls (PCB), to expose PBMC and test the reactions based on Apoptosis, Nitric oxide production and Cytokine expression (ANOPCE); (2) Using non-contaminated ground- and other treated waters suitable for drinking with ANOPCE; (3) Applying the ANOPCE-based method to various groundwater samples taken from a contaminated industrial site.
Methods: The method focussed on measuring in vitro immune responses of peripheral blood mononuclear cells harvested from human whole-blood. The responses measured were 1) Apoptosis (programmed cell death), and 2) inflammation characterised by increased nitric oxide production (NOP) and cytokine expression (CE).
Results: The following results were obtained:
Index chemical Time study: TCE increased cell viability and NOP in a time-dependent manner and ARO lead to increased IL-1β and Apoptotic cell death;
Index chemical Concentration study: ARO caused toxicity more acutely than TCE and the effects of DNAPL was not dose-dependent;
iii
Low-end reactivity benchmark: IL-8 was found to be expressed while the other pro-inflammatory cytokines appeared to be suppressed after exposure to reference waters;
Application to environmental waters: NOP, IL-1β and IL-8 where induced by some environmental waters and none of the waters showed attenuation in the effects of DNAPL as it’s migrates along the water table.
Conclusion: The applied method is only feasible when applied as a quick screening test to assess water quality and its effects on health rather than to test for the presence of DNAPL. By using these techniques one can assess the quality of water and determine whether the water contains substances that are pyrogenic (i.e. able to causes an immune response), but cannot identify the causal substance.