Data on elemental concentrations in marine sediments from the South and South West of England

The present Data In Brief methodological paper details the acquisition, mining and pre-processing of elemental concentration data in marine sediments (coastal and open sea) of Southern England, presented and discussed in the co-submitted Environment International paper entitled: "Three decades of trace element sediment contamination: the mining of governmental databases and the need to address hidden sources for clean and healthy seas" [1]. Elemental sediment concentration data were obtained from the two main UK environmental sources, i.e. the Environment Agency (EA) and the Marine Environment Monitoring and Assessment National (MERMAN) database managed by the British Oceanographic Data Centre (BODC). The merged database is the result of a rigorous data selection-validation process and provides spatially and temporally extensive records of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) concentrations for hundreds of sites over 31 years (1983-2013). Additional records of manganese (Mn), aluminium (Al), lithium (Li), tin (Sn) [and tributyltin (TBT)], barium (Ba), antimony (Sb), boron (B), calcium (Ca), molybdenum (Mo), cobalt (Co), selenium (Se), potassium (K), magnesium (Mg), beryllium (Be), vanadium (V), titanium (Ti), sodium (Na), silver (Ag), thallium (Tl) and strontium (Sr) are also included. The full secondary database is hosted in the Mendeley Data repository and the geo-spatial information to map sites is given in supplementary files to the paper. To provide end-users with the relevant context on spatial and temporal coverage, monitoring statistics are given for the nine trace elements (TEs). Site-specific statistics include: the first and last year of sediment monitoring, the number of years monitored, and minimum, maximum, mean and median numbers of years monitored. Also given are summary data on the number of sites monitored each year, from the first records from 1983 to 2013. For the nine TEs (total and strong acid digestion techniques are considered separately for Cr and Fe), monitoring statistics are presented separately for coastal and open sea sites. Data are relevant to diverse end-users to assess the local and regional contaminant loads and to contextualize anthropogenic threats to benthic systems in multiple locations from the French/English Channel, southern North and Celtic Seas.