The banning of tributyltin (TBT) from boat antifouling paints in the late 1980s led to its
replacement by alternative biocide additives (Voulvoulis et al., 2000; Marcheselli et
al., 2010), including Cu (Dahl & Blanck, 1996) and Zn as active ingredients. It has
been reported that Cu and Zn compounds associated with these biocides have
caused substantial contamination of harbour and marina sediments (Eklund et al.,
2010; Parks et al., 2010), with negative toxic consequences for aquatic organisms
(Ytreberg et al., 2010). Indeed, it is evident that Cu and Zn compounds present in
paint fragments are readily leached into the water column allowing entry into aquatic
food webs (Jessop & Turner, 2011). Nevertheless, relatively little is known regarding
antifoulant-derived metals contamination in freshwater lakes.
The Norfolk and Suffolk Broads (Eastern England, UK) have been contaminated by
antifoulant-derived heavy metals, particularly Cu and Zn which have increased since
the banning of TBT (post-1987) in parts of the boated system (Boyle et al., in prep.).
Further, recent studies suggest that current levels of sediment contamination by Cu
may have negative ecological effects for aquatic ecosystems including inhibition of
aquatic macrophyte germination and performance (Boyle et al., submitted; S.
Lambert, unpublished data).
In Hickling Broad (Thurne Broads system), post-TBT increases in Cu and Zn are also
evident, with an interesting peak in Cu for the late 1990s in core HICK1 (Figure 1).
This coincides with the large-scale loss of aquatic macrophytes (especially
Characeae) from the lake in 1999 (Barker et al., 2008). HICK1 was collected in 2003.
In the proposed study we sought to gain a fuller understanding of recent metal
contamination in Hickling Broad up to the present day, whilst looking to verify and
better contextualise the late 1990s Cu peak. Further, we aimed to determine whether
the peak in Cu for Hickling Broad was also recorded at Horsey Mere which is used as
a control site in this study i.e. is it just a Hickling phenomenon? Or is it a Thurne
Broads system-wide effect