The unsaturated (vadose) zone between the base of soils and the water table can be an important store of nitrate. Water moves slowly downward through the unsaturated zone and so a large store of nitrate can accumulate if this water contains nitrate derived from surface sources such as fertiliser. Release of this store can affect ground- and surface water quality for decades and it can continue for a long time after changes in farming practice that reduce nitrate leaching.

Here is a round up of metrics for October 2017. For all social media, the item shown is the most popular this month.

Updated: Links to public footpath closure notices added.

Groundwater researchers at the British Geological Survey (BGS) have found a major store of pollution sitting in the rocks beneath our feet that could have severe global-scale consequences for our rivers, water supplies, human health and the economy.

Updated: Minor details changed