State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
sites (concentrate shed wash bay, concentrate shed, multi-purpose quay and the concentrate quay)
over four years (1999-2002). It is clear that the estimated concentrations of many of the potentially
toxic compounds are above the South African water quality guidelines for coastal and marine waters
(marked in red). It is likely that introduction of contaminants via storm water runoff negatively
impact the health of the marine environment, especially during the “first flush” period as winter
rains arrive.
Table 4.7. Typical concentrations of water quality constituents in storm water runoff (residential and
Industrial) (from CSIR 2002) and South Africa Water Quality Guidelines for the Natural
Environment (*) and Recreational Use (**). Values that exceed guideline limits are indicated in
red.
Parameter Residential Industrial Water Quality
Guidelines
Total Suspended Solids (mg/l) 500 600 -
Chemical Oxygen Demand (mg/l) 60 170 -
Nitrate-N (mg/l) 1.2 1.4 0.015*
Total Ammonia-N (mg/l) 0.3 0.4 0.6*
Orthophosphate-P (mg/l) 0.07 0.1 -
Cadmium (mg/l) 0.006 0.005 0.004*
Copper (mg/l) 0.05 0.05 0.005*
Lead (mg/l) 0.3 0.1 0.012*
Zinc (mg/l) 0.4 1.1 0.025*
Faecal coliform counts (counts/100 ml) 48 000 48 000 100**
Storm water runoff is highly seasonal and peaks in the wet months of May to August. Due to
the rapid pace of holiday and retail development in the area, Langebaan residential area produces
the greatest volumes of storm water runoff, followed by the industrial areas, with lower volumes
arising from the Saldanha residential area (CSIR 2002). The actual load of pollutants entering the
Bay and Lagoon via this storm water can only be accurately estimated when measurements of storm
water contaminants in the storm water systems of these areas are made.
4.3.8 Fish processing plants
Three fishing companies discharge wastewater into Saldanha Bay: Sea Harvest, SA Lobster
Exporters (Marine Products), Live Fish Tanks (West Coast) – Lusithania (CSIR 2002). Southern Seas
Fishing previously discharged wastewater into the Bay but closed its factories approximately 5 years
ago. The locations of the fish factory intake and discharge points are shown in Figure 4.24. The
composition of the effluent from Southern Seas Fishing and Sea Harvest was surveyed in 1996/7 and
2001, respectively (Entech 1996 In CSIR 2002). Monthly discharge for the Sea Harvest factory was in
the region of 70 000 m 3 /month in 2001 and from Southern Seas Fishing more than double that (160
000 m 3 /month) in 1996/7. Although the water quality of the outflow from SA Lobster Exporters and
Live Fish Tanks are not monitored, it is reported to be not markedly different from ambient
seawater, as it basically cycles through tanks where live lobsters are kept prior to packaging (CSIR
2002).
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 79