Abstract Gypsum and anhydrite are both soluble minerals that form rocks that can dissolve at the surface and underground, producing sulphate karst and causing geological hazards, especially subsidence and sinkholes. The dissolution rates of these minerals are rapid and cavities/caves can enlarge and collapse on a human time scale. In addition, the hydration and recrystallization of anhydrite to gypsum can cause considerable expansion and pressures capable of causing uplift and heave. Sulphate-rich water associated with the deposits can react with concrete and be problematic for construction. This paper reviews the occurrence of gypsum and anhydrite in the near surface of the UK and looks at methods for mitigating, avoiding and planning for the problems associated with these rocks.

Abstract Radon ( 222 Rn) is a natural radioactive gas that occurs in rocks and soils and can only be detected with special equipment. Radon is a major cause of lung cancer. Therefore, early detection is essential. The British Geological Survey and Public Health England have produced a series of maps showing radon affected areas based on underlying geology and indoor radon measurements, which help to identify radon-affected buildings. Many factors influence how much radon accumulates in buildings. Remedial work can be undertaken to reduce its passage into homes and workplaces and new buildings can be built with radon preventative measures.

Abstract This paper identifies potential sources, and the key chemical properties, of methane. Guidance is provided on deriving a conceptual site model for methane, utilizing various lines of evidence to inform a robust, scientific, reasoned and logical assessment of associated gas risk. Discussion is provided regarding the legislative context of permanent gas risk assessment for methane, including via qualitative, semi-quantitative and detailed quantitative (including finite element modelling) techniques. Strategies for mitigating risks associated with methane are also outlined, together with the legal context for consideration of methane both in relation to the planning regime and under Part 2A of the Environmental Protection Act 1990.