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					Aim
     The overall aim of the Falmouth field course is to investigate the biological, chemical and
geophysical properties of the Fal estuary and develop an understanding of the processes and
interactions occurring within and offshore of the estuary.

Physical description
     The Fal estuary is a drowned river valley or ria, located in Cornwall on the South-West coast of
the UK. It was formed in the Quaternary as a wide river valley, and has evolved to become a ria due
to tectonic subsidence and sea level rise. After the end of the last ice age, approximately 10,000
years ago, the ice sheet over Scotland began to melt. Since then, the isostatic recovery has caused
the South of England to sink as Scotland has undergone tectonic uplift. This, combined with rising
sea levels has submerged the Fal estuary and also resulted in the formation of extensive wetlands.
     The entrance to the estuary is located between Pendennis Point and St Anthony Head and is
tidal up to 18km inland of this point. The estuary is supplied by 6 main rivers including the Fal, the
Truro and the Tresillian, and 28 minor creeks and rivers which all flow into Carrick Roads (one of the
largest natural harbours in the world – REF PDF). The Fal estuary has depths of up to 34m and is
macrotidal at Falmouth with a maximum spring tide of 5.3m and mesotidal at Truro with a maximum
spring tide of 3.5m. (Pirrie et al.)

(map showing carrick roads, fal estuary, etc. From PDF)


Area of conservation
The Fal estuary is now a designated special area of conservation (SAC) of 6387.8 ha (JNCC). This area
is home to a wide range of communities, including the largest maerl beds in South-west England
(Phymatolithon calcareum [Pallus 1970] and Lithothamnion coralloides [Crouan 1867].) There is also
a significant proportion of seagrass beds (Zostera marina NEED AUTHORITY) and important sediment
dwelling species including amphipods, polychaetes and bivalve molluscs.

Anthropogenic Inputs
Despite being ecologically important, the Fal estuary has a history of negative anthropogenic
impacts. There is sewage release at Truro Newham Sewage Treatment Works and at Black Rock.
Between 1995 and 1996 there was a toxic algal bloom of the dinoflagellate Alexandrium tamarense
due to eutrophication from sewage contamination. Other excess nutrients are continuously added
to the estuary from local intensive farming.
In spite of the decrease in industrial operations in the surrounding area, the Fal estuary is still
subject to continuous pollution. The main source of this comes from Falmouth docks where the
processes of dredging, oil leakage and use of heavy metal products such as TBT has lead to this
contamination. Although TBT has been banned since 1987, re-release from sediments still
significantly contributes to the overall load (Langston et al. 2003) and the concentration still exceeds
the EQS of 2ng/L.
Tailings from local mining activity (such as the currently inactive Jane Wheal Mine,) containing Sn,
Cu, Pb and Fe have made the area the most metal polluted estuary in the UK (Bryan and Langston,
1992).
References

JNCC http://www.jncc.gov.uk/protectedsites/sacselection/sac.asp?EUcode=UK0013112

Pirrie, D., Power, M.R., Rollinson, G., Hughes, S.H., Camm, G.S. and Watkins, D.C. no date, Mapping
and visulisation of the historical mining contamination in the Fal Estuary,
 Cornwall, [website], Available: http://projects.exeter.ac.uk/geomincentre/estuary/Main/intro.htm
[accessed 1st July 2010]

PDF from steve

Bryan, G. W. and Langston, W.J. 1992, Bioavailability, accumulation and effects of heavy metals in
sediments with special references to United Kingdon estuaries: a review, Environmental Pollution, 76,
pgs 89-131

(Langston, W.J., Chesman, B.S., Burt, G.R., Hawkins, S. J., Readman, J. and Worsfold, P. 2003, Site
Characterisation of the South West European Marine Sites: Fal and Helford, cSAC, MBA, Plymouth

				
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posted:12/20/2011
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