Quantification of soil pollutant bioavailability by integrating chemical and biological measurements

There is significant concern about the accumulation of potentially toxic elements (PTEs) in soils because of both direct and indirect impacts on human and ecosystem health. Knowledge of the fate and distribution of such contamination can lead to an effective assessment of the hazards to soil biota and the need for protective or mitigation activities. This is a particular challenge due to the heterogeneity of the soil matrix and complexity of the processes that determine PTE availability to soil biota. While whole-cell bacterial biosensors have been proposed as tools in enabling greater confidence in addressing such biological and chemical interfaces their genuine value remains to be realised. The underpinning objective of this work was to link the response of microbial biosensors to detailed chemical analysis and to relate the dose response sensitivity to other biological measurements. To better understand the phenomena of PTE bioavailability, the study considered changes in toxicity within the context of ion competition in both freshly amended and historically impacted soils. The interaction of test bacteria with both free (soil pore water) and sorbed (solid phase) fractions of the target analytes (copper, nickel and zinc) has enabled a better estimation of bioavailability/toxicity of PTEs in soils. In comparison to other assays, the responses of the microbial sensor to Cu, Ni and Zn highlighted its relative sensitivity to PTE contamination. The use of luminescence marked microbial sensors complements the performance of rigorous analytical soil chemistry approaches. Their value in soil pollution should be considered a technique that should be interpreted alongside chemical analysis rather than an alternative as their performance in complex environmental matrixes is yet to be validated.EThOS - Electronic Theses Online ServiceGBUnited Kingdo