Arsenic often appears in minerals rich in iron and sulphur, such as pyrite (fools' gold).
Scientists working as part of eMinerals project have found out precisely how arsenic is taken up and held in the pyrite structure and the factors likely to lead to its release.
"We now know that arsenic replaces the sulphur in pyrite rather than the iron, and that pyrite is likely to dissolve more easily when arsenic is present," said Dr Kate Wright, who worked on the project.
He, however, said that further work would be necessary to identify ways of stabilising arsenic-containing iron sulphide rock by introducing additives that slow the rate at which it dissolves.
During the study, the researchers also found that a dioxin molecule that contains more chlorine atoms binds more strongly to the clay surfaces, irrespective of the position of the chlorine atoms in the molecule.
The binding becomes stronger if there is a greater electrical charge on the surface, the study revealed.
However, water competes with dioxin to bind to surfaces and, in practice, a dioxin molecule's ability to bind to a surface is a balance between the binding strength of the dioxin to the surface, the water to the surface, and the dioxin to the water, the researchers said.
EMinerals principal investigator, Prof. Martin Dove said as there are 76 known different variants of the dioxin molecule and numerous mineral surfaces in the environment to which they can attach, they developed a grid infrastructure consisting of clusters and condor pools that can be accessed for particularly large simulations if necessary.
He said without access to such grid resources, scientists would have to perform all of the simulations sequentially, taking too much time to be practicable.
"Using the eMinerals infrastructure, they can submit all these jobs at once and see the results within a few hours. Results are automatically returned to a distributed data store with an interface that shows the files as if they are part of a single system. The data can be accessed remotely by collaborating scientists, as well as by those who originally submitted the job," said Prof. Dove.
"We're doing grid properly. We can submit hundreds of jobs from the user's desktop to a number of different compute grids, and get the data back with metadata attached and with the analysis done - and in a state that enables collaborators to understand what the simulations are saying. We're giving control back to the user," he said.
Prof. Dove and other members of the eMinerals team will be talking about results from the project and demonstrating the eMinerals technology at the 7th UK e-Science All Hands Meeting in Nottingham on 10-13 September 2007. (ANI