1. Testing the palaesol model of arsenic pollution in groundwater
Our 'palaeosol' project (McArthur / Hoque) is funded by NERC and will test the validity of a new model proposed recently that might explain the spatial distribution of As-pollution in deltaic aquifers. This 'palaeosol' model (McArthur et al. 2008, Water Resources Research) proposes that the spatial distribution of As-pollution in the Bengal Basin, and so other deltas, is controlled primarily by the distribution of palaeo-channels and palaeo-interfluves developed in the period preceding the last glacial maximum, when sea-level was up to 120 m lower than it is today.
Outline evolution of the Bengal Basin's sedimentary architecture. At 20 ka, the lowstand of sea level at the Last Glacial Maximum causes deep erosion in paleochannels. Higher gradients than in the present caused the rivers to flow more directly south than they do today. Interfluvial areas were deeply weathered by the high rainfall and developed a widespread paleosol of impermeable clay that is found widely today across the Bengal Basin....more...
2. Microbial mechanism of natural arsenic mobilisation in groundwater
Our microbiology project (McArthur / Santini) is also NERC-funded. Using DNA and RNA profiling, we aim to identify the microbiological agents actually causing the As-pollution in southern West Bengal and, by implication, across the Bengal Basin. Is the pollution simply the result of FeOOH-reducing bacteria, or are other microbes involved, such as obligate As(V) respirers? Our microcosm experiments in the field will, we hope, provide the answer.