title: A temporal and spatial assessment of TBT concentrations at dredged material disposal sites around the coast of England and Wales.
abstract: Despite legislative interventions since the 1980s, contemporary concentrations of organotin compounds in marine sediments still impose restrictions on the disposal of dredged material in the UK. Here, we analyse temporal and spatial data to assess the effectiveness of the ban on the use of TBT paints in reducing concentrations at disposal sites. At a national scale, there was a statistically significant increase in the proportion of samples in which the concentration was below the limit of detection (LOD) from 1998 to 2010. This was observed for sediments both inside and outside the disposal sites. However, this temporal decline in organotin concentration is disposal site-specific. Of the four sites studied in detail, two displayed significant increases in proportion of samples below LOD over time. We argue that site-specificity in the effectiveness of the TBT ban results from variations in historical practices at source and unique environmental characteristics of each site.
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK. Electronic address: thi.bolam@cefas.co.uk.
authors.forename: Thi
authors.initials: T
authors.lastname: Bolam
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Barry
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Law
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: David
authors.initials: D
authors.lastname: James
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: Boby
authors.initials: B
authors.lastname: Thomas
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: Bolam
mesh_terms: D004739:England; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D009947:Organotin Compounds / Q000032:analysis*; D012767:Ships; D014852:Wales; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009947:Organotin Compounds; D014874:Water Pollutants, Chemical
keywords: Dredged material; England and Wales; Organotins; Temporal assessment