title: Estimating the spatial distribution of dredged material disposed of at sea using particle-size distributions and metal concentrations.
abstract: We present a method to estimate the spatial distribution of dredged material disposed of at sea. Using both dredged sediments and samples of sea-bed sediment from near the Rame Head disposal site, Plymouth, UK, we applied entropy analysis to the <63 microm sediment fraction and combined the results with the trace metal data in the same fraction, to form a series of groups. We interpret the distribution of sediments in one group (F1) to approximate the distribution of material affected by the disposal site. This distribution includes locations close to the disposal site, and also locations <4 km to the SE and SW, <6 km to the NW and <2 km to the N. This approach demonstrates the feasibility of using trace metal analysis of particular grain size fractions to reduce uncertainty in interpreting the spatial distribution of impacts of dredge disposal.
authors.affiliation: National Institute for Land and Infrastructure Management, 3-1-1 Nagase, Yokosuka, Kanagawa 239-0826, Japan.
authors.forename: Tomonari
authors.initials: T
authors.lastname: Okada
authors.affiliation: Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK. Electronic address: piers.larcombe@cefas.co.uk.
authors.forename: Piers
authors.initials: P
authors.lastname: Larcombe
authors.affiliation: Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Mason
mesh_terms: D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D019216:Metals, Heavy / Q000032:analysis*; D009792:Oceans and Seas; D010316:Particle Size
chemical_list: D019216:Metals, Heavy