State of the Bay Report 2010-Final - Anchor Environmental
State of the Bay Report 2010-Final - Anchor Environmental
State of the Bay Report 2010-Final - Anchor Environmental
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<strong>State</strong> <strong>of</strong> <strong>the</strong> <strong>Bay</strong> <strong>2010</strong>: Saldanha <strong>Bay</strong> and Langebaan Lagoon<br />
<strong>Anchor</strong> <strong>Environmental</strong><br />
microwave digestion, has recently been adopted, and should ensure that such problems do not<br />
recur in <strong>the</strong> future (Watling 1981; G. Kiviet pers. comm.). Data from <strong>the</strong> mussel watch programme<br />
are represented in Figure 5.10 where <strong>the</strong> maximum legal limits prescribed for each contaminant in<br />
shellfish for human consumption in South Africa, as stipulated by <strong>the</strong> Regulation R.500 (2004)<br />
published under <strong>the</strong> Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 <strong>of</strong> 1972), are<br />
indicated in red text. Where guideline have not been specified in national legislation those adopted<br />
by o<strong>the</strong>r countries have been used (Table 5.10).<br />
Data supplied by <strong>the</strong> Mussel Watch Programme (Figure 5.10) show that concentrations <strong>of</strong><br />
Lead in mussels at <strong>the</strong> monitored sites are consistently are above guideline limits for foodstuffs for<br />
at least <strong>the</strong> last 10 years, while concentrations <strong>of</strong> Cadmium frequently exceed <strong>the</strong>se limits, and those<br />
for Zinc do so occasionally. Concentrations <strong>of</strong> Copper are, however, well below specified levels<br />
(Table 5.10). No clear trends over time are evident for any <strong>of</strong> <strong>the</strong> trace metals, although recent data<br />
(post 2007) are lacking.<br />
Concentrations <strong>of</strong> Lead in mussel from Saldanha <strong>Bay</strong> tend be consistently high at <strong>the</strong> TNPA<br />
site (at <strong>the</strong> base <strong>of</strong> <strong>the</strong> iron ore terminal on <strong>the</strong> Small <strong>Bay</strong> side, values generally greater than 60<br />
ppm), occasionally spiking to very high level at this site (715 ppm in Oct 2001), but tend to be lower<br />
at <strong>the</strong> o<strong>the</strong>r sites (mostly below 10 ppm), although <strong>the</strong>y occasionally spike to high levels at <strong>the</strong>se<br />
sites as well (e.g. 250 ppm at <strong>the</strong> mussel rafts site at <strong>the</strong> base <strong>of</strong> <strong>the</strong> Marcus Island causeway).<br />
Compared with <strong>the</strong> guideline limit <strong>of</strong> 0.5 ppm <strong>the</strong>se levels are extremely high and are very<br />
concerning. These high levels <strong>of</strong> Lead in are almost certainly linked to <strong>the</strong> export <strong>of</strong> lead ore from<br />
<strong>the</strong> multipurpose quay, which is situated in close proximity to <strong>the</strong> TNPA site. Levels <strong>of</strong> Cadmium in<br />
mussels from Saldanha <strong>Bay</strong> are less variable than lead and appear to be <strong>of</strong> a similar magnitude at all<br />
sites (mostly between 1-10 ppm) but occasionally exceed this level. Relative to guideline levels this<br />
is very high and is also cause for concern for anyone who may be consuming <strong>the</strong>se mussels. Levels<br />
<strong>of</strong> Zinc are mostly within <strong>the</strong> range <strong>of</strong> 50-200 ppm but occasionally have been observed to spike to<br />
levels as high as 400 ppm or more which is way in excess <strong>of</strong> <strong>the</strong> guideline limit <strong>of</strong> 150 ppm listed by<br />
<strong>the</strong> Canadian authorities (Table 5.10).<br />
Rights holders engaged in bivalve culture (mussels and oysters) in South Africa are also<br />
required to report on concentrations in harvested organisms on an annual basis. Data were<br />
obtained for three trace metal indicators (Cadmium, Lead and Mercury) for three farms (Blue <strong>Bay</strong><br />
Aquafarm, West Coast Aquaculture, West Coast Oyster Growers and Striker Fishing) in Saldanha <strong>Bay</strong><br />
covering <strong>the</strong> period 1993-<strong>2010</strong> (Figure 5.11). Data from <strong>the</strong>se farms suggest that <strong>the</strong> situation in <strong>the</strong><br />
deeper parts <strong>of</strong> <strong>the</strong> <strong>Bay</strong> where <strong>the</strong> farms are located are less <strong>of</strong> a problem than is <strong>the</strong> case with <strong>the</strong><br />
nearshore coastal water where <strong>the</strong> samples for <strong>the</strong> Mussel Watch programme are collected.<br />
Concentrations <strong>of</strong> Lead were consistently above guideline levels in <strong>the</strong> period prior to 2000, albeit<br />
nowhere near as high as for <strong>the</strong> nearshore mussel samples (never more than 3 ppm), but since this<br />
time have been mostly within guideline limits (i.e. less than 0.5 ppm). Concentrations <strong>of</strong> Mercury in<br />
<strong>the</strong> mussel flesh from <strong>the</strong> farms has also mostly been within guideline limits (i.e. less than 0.5 ppm),<br />
apart from one or two spikes above this level (maximum concentration recorded = 1.7 ppm in 1994).<br />
Concentrations <strong>of</strong> Cadmium have always been within guideline limits (