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Title: Fal Estuary TBT monitoring programme : 1997 baseline survey : tidal water quality
Author: Environment Agency South West Region
Document Type: Monograph
Annotation: EA additional title info: November 1998
Historically, samples of water and sediments taken in the Fal Estuary have shown very high levels of Tributyltin (TBT), with levels in sediments being among the highest found in the UK. TBT is a prescribed substance for release to water and is also a List II substance with an Environmental Quality Standard (EQS)of 2 ng TBT/l. TBT is known to be toxic to aquatic organisms by affecting a wide range of fundamental biological processes at very low concentrations, and since 1987 its use for antifouling boats of under 25m has been banned. However, discharges to the marine environment in the Falmouth area continue from dockyard activities, leaching from historically contaminated sediments and other diffuse sources. TBT has a variable half life depending on where it is found, e.g. 9-19 months in aerobic sediments, at least 21 months in anaerobic sediments, and in the order of 20 years for very highly contaminated sediments(l). Although this study focuses on levels ofTBT and Dibutyltin (DBT), studies conducted by MAFF between 1986 and 1993 also identified the presence o f Triphenyltin (TPT), albeit in much lower concentrations than TBT. TPT ceased to be used in antifoulants in 1995 as a result of the Pesticides Advisory Committee review on the use of triorganotins (HSE pers comm). The most significant source ofTBT input to the Fal area is Falmouth Dockyard. The overall aim of the sampling programme is to monitor the Fal Estuary with respect to TBT for the long-term achievement of Environmental Quality Standards.
Publisher: Environment Agency
Publication Date: 1998
Publication Place: Exeter
Subject Keywords: Toxic substancesEstuariesRiversPollution monitoringMusselsEffluentsHarbours
Geographic Keywords: Fal EstuaryWest Cornwall and the Fal catchmentFalmouth
Extent: 14; + tables, figures
Total file downloads: 42

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