Determining the intrinsic potential for ether oxygenate degradation in the Chalk aquifer

This project examines the environmental conditions which determine the potential for degradation of the ether oxygenates MTBE and TAME in the saturated zone of the UK Upper Chalk aquifer.

The surface of a pond reflecting the reeds and mossy wall behind it.


MTBE was first used in the 1970s as an alternative to alkyl lead additives but its use increased significantly in the 1990's when it was used as an oxygenate in fuel to reduce atmospheric concentrations of carbon monoxide and ozone.

However, it has been found in groundwater, both in the US and Europe and, due to its very low taste threshold, it is has attracted environmental, political and scientific attention.

Although often considered relatively recalcitrant, an increasing number of studies have shown that MTBE can biodegrade aerobically by different pathways. However, rates of degradation are highly variable and little is known about the degradation of MTBE and other ether oxygenates in UK aquifers.

This project sets out to determine the intrinsic potential for aerobic degradation of ether oxygenates in the Chalk aquifer at a petroleum spill site in Southern England and is linked to ongoing research into processes controlling the natural attenuation of fuel hydrocarbons and MTBE in the chalk aquifer.

Project aims

  • Deducing the intrinsic potential for MTBE degradation in the Chalk aquifer under field conditions.
  • Identifying whether degradation occurs at environmentally significant rates for site management using MNA.
  • Determining the environmental factors which control degradation in the Chalk aquifer.
  • Identifying if degradation can be enhanced by modification of the environmental conditions for site management using engineered bioremediation.

Scientific approach

Degradation of MTBE and TAME will be assessed in laboratory microcosms under a range of environmental conditions, which mimic those occurring in the Chalk aquifer at the site.

Rock core and groundwater collected from the site will be used in experiments which evaluate the effects of dissolved oxygen concentration, MTBE concentration, nutrient status and contaminant matrix on degradation under aerobic conditions.

These experiments will be interpreted to determine the bioavailability of dissolved oxygen for oxygenate degradation, degradation kinetics and competitive or inhibitory effects of other contaminants on MTBE degradation.

Project partners

  • Total UK

Centres of excellence

The University's cross-faculty research centres harness our interdisciplinary expertise to solve the world's most pressing challenges.