State of the Bay Report 2011-Final.pdf - Anchor Environmental

Number and type of vessels entering Saldanha Port
State of Saldanha Bay & Langebaan Lagoon 2011
Activities & discharges
Table 3.4.
Mean trace metal concentrations in ballast water (mg/l) and ballast tank sediments from ships
deballasting in Saldanha Bay (Source: Carter 1996) and SA Water Quality Guideline limits
(DWAF 1995a). Those measurements in red are non-compliant with the guidelines.
Water Sediment SA WQ Guideline limit
Cd 0.005 0.040 0.004
Cu 0.005 0.057 0.005
Zn 0.130 0.800 0.025
Pb 0.015 0.003 0.012
Cr 0.025 0.056 0.008
Ni 0.010 0.160 0.025
The total number of ships entering the Port of Saldanha has nearly doubled in the last two
decades and in 2011, there were 463 ships which visited the port (Figure 3.11). The average size of
vessels in use has also increased over the years, and as a result, the volume of ballast water
discharged to the Bay has increased by more than double since 2004, with over 20 million tons of
ballast water being discharged each year (Figure 3.12). Iron ore tankers are responsible for most of
the observed increase in vessel traffic and are the ones responsible for discharging the greatest
volume of ballast water into the Bay.
500
450
400
350
TOTAL
MPT
Other
IOT
Tanker
300
250
200
150
100
50
0
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Figure 3.11. Number and types of vessels entering Saldanha Port from 1994-2011. (Sources: Marangoni
1998; Awad et al. 2003, Transnet-NPA).
Associated with this increase in shipping traffic, is an increase in the incidence and risk of oil
spills, the risk of introducing alien species, increases in the volume of trace metals entering the Bay,
and direct disturbance of marine life and sediment in the Bay. While the risks associated with
introduction of alien species to the Bay are being addressed through various mechanisms including
open-ocean exchange and treatment of ballast water, risks of oil spills are being addressed through
oil spill contingency planning, no measures have yet been put in place to address trace metal
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