A STRANGE-looking plume of discoloured water has been appearing sporadically in the bay between Shark Rock Pier and Humewood Beach, resulting in a number of calls from concerned residents, Following an initial report on May 20 by Humewood resident Elize Pretorius, and then disappearing for several days, it reappeared again this week, prompting further calls.
At low tide, the milky gunge collects in the rock pools on the edge of the water beneath the outlet of a stormwater drain diagonally opposite the Hobie Beach pub and restaurant complex and, as the tide gets higher, this gunge is flushed out into the bay.
Nelson Mandela Bay Municipality beach manager Fernando Cain said he took a sample of the material yesterday and it is being analysed by the Nelson Mandela Bay Municipality’s scientific services’ department.
“We will wait and see for sure what the results say but at this stage the thinking is that it could just be underground water that has mixed with building sand from the Boardwalk building site.
“We had a report last week from the site that they had pierced groundwater during their excavation operations and that this water had mixed with building material and flowed into the stormwater drain.”
The results of the test should be available soon and if they do not match this scenario then further investigations will be done, he said.
Last week, NMBM coastal environment unit Godfrey Murrell said another contributor could be the clay material excavated at the site that is being blown from transport trucks and which is then being washed off the roads by the recent rains, into the stormwater system. The trucks are transporting excavated rock out to Driftsands where it is being stockpiled for future use on roads.
Marine biologist and crustaceans’ specialist Prof Tris Wooldridge said even if the pollution is just suspended clay sediment, as seems to be the case, it could cause problems for crabs or other life in the rock pools.
“It could smother their gills and clog their breathing apparatus. Even if it is flushed out from the rocks with each high tide, you could well have mortalities.”