State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
concentrations away from the shore are much lower than those in nearshore water and mostly meet
guidelines for foodstuffs for human consumption.
In the light of the fact that large qualities of shellfish are harvested and consumed by
recreational and subsistence fishers from the shore of the Bay, it is imperative that this Mussel
Watch Program is continued and possibly extended to cover other species as well (e.g. fish).
13.2.5 Microbiological monitoring (Faecal coliform)
Water samples are currently analysed fortnightly for faecal coliform and E. coli
concentrations from 18 stations in Saldanha Bay and Langebaan Lagoon. Faecal coliform counts in
Small Bay regularly exceed water quality guidelines for recreational and mariculture use. Despite
guideline values being exceeded in Small Bay, there has been a general improvement in water
quality over the last decade. Water quality (bacterial counts) for Big Bay fall mostly below guideline
limits, however there has been a notable decline in water quality within Big Bay over time and this is
of some concern. There does not appear to be any bacterial contamination within Langebaan
Lagoon (with occasional exceptions), but unmitigated erosion of Langebaan beach may increase the
risk of sewage pollution via broken or leaking sewage holding tanks. It is imperative that
management steps are taken to improve water quality within Small Bay, especially in the vicinity of
the Bok River mouth (sewage outlet). The upgrading of sewage treatment and storm water facilities
needs to match the rate of development in order to prevent any further degradation of water
quality within the Bay. The current level of monitoring should continue as such with regular analysis
and interpretation of data taking place.
13.3 Sediments
13.3.1 Particle size, Particulate Organic Carbon and Trace metals
Sediment monitoring in the Bay has revealed that key heavy metal contaminants (Cd, Pb, Cu,
Ni) are increasing at a number of sites in the Bay, particularly in Small Bay, to the extent that they
are almost certainly impacting on benthic fauna and possibly other faunal groups in the Bay. These
contaminants are typically associated with the finer sediment fraction and are highest in the most
quiescent areas of the Bay (i.e. In the Yacht basin and adjacent of the Multipurpose terminal).
Sediment monitoring (particle size, particulate organic carbon and trace metals) should
continue to be conducted annually at the same suite of stations that have been monitored since
1999 along with additional stations added since this time (e.g. those in Langebaan Lagoon).
Dredging in the Bay should be avoided if at all possible, and appropriate precautions need to be
taken when dredging become necessary to ensure that suspended trace metals do not reach
cultured organisms in the Bay.
13.3.2 Hydrocarbons
Poly-cyclic, poly-nuclear compounds, and pesticides were considered to pose no threat
during analysis conducted in 1999. This has been confirmed through more recent studies (2010). It
is recommended, however, that these pollutants should be monitored approximately every five
years.
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 261