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

State of Saldanha Bay & Langebaan Lagoon 2011
Recommendations
12.8 Summary of environmental monitoring requirements
In summary, the environmental monitoring currently implemented in Saldanha Bay and Langebaan
Lagoon (e.g. sediment, benthic macrofauna and birds) should continue with some small adjustments
or additions, however, monitoring of other environmental parameters that are not currently
assessed on a regular basis (e.g. temperature, oxygen, rocky intertidal and fish populations) require
structured, maintained monitoring to be implemented.
Table 11.1. Tabulated summary of Environmental parameters reported on in the State of the Bay: Saldanha
Bay and Langebaan Lagoon.
Parameter monitored Time period Anthropogenic induced impact
Water Quality
Physical
aspects 1974-2000 No clear change attributable to development
(temperature, salinity,
dissolved oxygen, nutrients
and chlorophyll)
Current circulation patterns
and current strengths
1977 vs. 1991 Reduced wave energy, and impaired circulation
and rate of exchange in Small Bay
Increased current strength alongside obstructions
(e.g. ore terminal)
Microbiological (faecal 1999-2011 Faecal coliform counts in Small Bay frequently
coliform)
exceed safety levels.
Big Bay and Langebaan Lagoon mostly remain
within safety levels for faecal coliform pollution
Heavy metal contaminants
in water
1997-2008 Concentrations of cadmium, copper, lead, zinc,
iron and manganese in mussel flesh currently well
below required safety levels, but this may change
following any future dredging events owing to
elevated metal concentration in sediments.
SEDIMENTS
Particle
(mud/sand/gravel)
size
Particulate Organic Carbon
(POC)
Particulate Organic Nitrogen
(PON)
Trace metal contaminants
in sediments
1977-2011 Mud component of sediments has increased as a
result of reduced water movement and dredging
(negative impact) but has recovered somewhat
since the last major dredging events (1999 and
2007).
1974-2011 Elevated levels of POC evident at Yacht Club basin
and Mussel Farm (negative impacts). POC
increased in 2008-2009 at Multi-Purpose Terminal
and Yacht Club basin.
1974-2010 PON concentrations have increased steadily over
time in Yacht Club basin and at multipurpose quay.
PON concentrations remain low in Big Bay.
1980-2011 Cadmium, lead, copper and nickel are currently
elevated considerably above historic levels.
Concentrations were highest in 1999 following
major dredge event. Pb, Cu, Ni elevated in 2008-
2010 at Yacht Club and multipurpose terminal,
which may be related to maintenance dredging
that occurred at end 2007/beginning 2008.
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