Data are submitted to the MERMAN database from relevant Competent Monitoring Authorities. A series of templates are populated by submitting officers and submitted to the database which has in-built data restrictions and a data filter to ensure high quality, accurate data are submitted. The data filter has formulae in-built which use Accredited Quality Control information from known standards, limits, standard deviations and/or inter laboratory calibration exercises to calculate a score. Only data that pass a threshold agreed with the national advisory bodies are used for assessments. The data for 1999 - 2015 were extracted from MERMAN. Further data checks were made and records with obvious errors were deleted or corrected. The concentration and biological effects data were standardised to agreed units and bases and, in the case of sediment, were normalised to 5% aluminium (metals) and 2.5% organic carbon (organics). The data were grouped into time series, typically of a single contaminant in a single species at a single monitoring station. Time series with no data for the period 2010 - 2015 were excluded. The data archived here are those for selected metals, polycyclic aromatic hyrdocarbons, polychlorobiphenyls, polybrominated diphenyl ethers, imposex (VDS), EROD and bile metabolites. The methods used to assess the individual time series and synthesise the results at a regional level can be found at https://www.bodc.ac.uk/projects/data_management/uk/merman/assessments_an.... The results can be found at the same location.