SANParks spokesperson, Zanemvula Gozongo gave the assurance that, "signage warning lagoon users had been erected". He added that warning signs had been erected at "Long Street, Oystercatcher, Loerie Park, Train Bridge, Queen Street and Cathy Park".
However, several boat users remarked that they had been boating throughout the season, but failed to notice any signs warning them of the high bacterial load at the train bridge. When first asked about the high bacterial load at the train bridge, Knysna acting municipal manager, Lauren Waring explained, "Unfortunately the chlorination device used at the train bridge culvert was stolen. That is why, on the date in question, this culvert showed a higher bacterial load than the other chlorination sites. We have been using alternative chlorination methods at this site since the theft."
Consequent to a web article reporting the above, published on January 12, Waring made an online comment: "A clear distinction needs to be made between the stormwater culvert located near the train bridge, referred to as the train bridge culvert, and the main channel flowing underneath the actual train bridge.
"When speaking about results read at the train bridge culvert, we refer to water sampled at the very mouth of the culvert where water from the stormwater system enters the estuary. The main channel underneath the train bridge is a completely different site to that of the culvert and would reflect different readings due to the movement of water, coupled with larger volumes of water flowing in the main channel."
Waring continued: "SANParks has confirmed that aside from samples taken in the Ashmead channel during August to October last year, when problems were experienced at the wastewater treatment works, all samples taken of the deep water channels, where boating activities take place, have complied with recreational standards."
The warning on the Knysna Municipal website clearly stated that the the levels of bacteria on December 22 exceeded recreational levels at the "Train Bridge" and not the Train Bridge culvert as indicated in Waring's comment.
Waring explained, "It is correct that the notice does not read 'Train Bridge culvert', but 'Train Bridge'. This does however not change the fact that all previous readings attributed to 'Train Bridge' were actually taken at the culvert, and not from within the main channel under the bridge where boating takes place." She further explained that, upon reading the web article, she realised that "confusion had crept in regarding bacterial load readings taken at the culvert being read as those present within the main channel. That is why I posted the comment on the website - to make this clear distinction. That is also why all municipal updates of estuary pollution levels now clearly identify this particular sampling point as the Train Bridge culvert."
Samples for analysis were taken from the estuary on January 10 and again on Monday, January 23. The results of the latter samples had not yet been received, but will be updated on www.knysna.gov.za as soon as the municipality receives them, explained Waring. She added that testing had to be temporarily suspended for the week of January 16 to 20 to facilitate the re-evaluation of testing sites in accordance with a proposed plan to deal with the problem of polution.
According to the municipal website, pollution levels, as measured on January 10, are as follow:
- Ashmead Channel - 1 110 E.coli/100ml;
- Bongani Stream - 1 986/100ml;
- Queen Street culvert - >2 419 E.coli/100ml;
- Long Street culvert - > 2419/100ml;
- Oyster Catcher culvert - > 2419/100ml;
- Train Bridge culvert > 1986/100ml.
In response to the high levels of bacteria Waring explained, "We realise that this historic problem of pollution in the estuary is primarily caused by external factors and have formulated a proposal to identify and deal with these factors." This proposal will be tabled to council at its January 26 meeting. "We must however also take into account that factors beyond our control may play a hand in this problem," she added.
Waring referred to aquatic and estuarine ecologist, Professor Brian Allanson's explanation that long periods of hot weather, such as the recent heat wave may play a role in the high bacterial count measured at certain times. "According to the professor, as ambient temperatures approach 35ºC - 38ºC, surface water temperatures will also increase and affect the growth and multiplication cycles of coli-forms, particularly E.Coli. In the presence of sufficient organic matter these cells will multiply," she said, and added, "Given that some bacteria can divide in only 20 minutes, it is apparent how numbers can increase quite markedly - even in an environment external to the body."
While many people have expressed their concern about the consumption of fish that may have been feeding in water with a high E.Coli count, researchers at the University of Minnesota Duluth reported in a 2008 study of E.Coli in wild fish of Lake Superior (Minnesota, USA), "There are certainly a few E.Coli that can cause disease, but people shouldn't be overly concerned about eating fish, especially if they don't cut the intestines open and smear the contents all over the fish that they're going to eat, which most people don't."
* The Knysna Municipality is aware that Waring estuary pollution updates on its website had intermittently been unreadable. To resolve such problems, the municipality now converts and publishes all updates as Adobe documents.
