"Severely flawed" seaweed report doesn't hold water

Wednesday 02 November 2016

A report into sewage outflows at Bellozanne has been branded “severely flawed” - with the result that a further report has now been ordered.

The serious on-going problem with seaweed in St Aubin’s Bay, which this summer – and previous summers - produced a thick green carpet in one of the most picturesque vistas in Jersey, was raised again in the States Assembly yesterday.

Following a question by Senator Sarah Ferguson, Infrastructure Minister Eddie Noel admitted a report into the causes of the seaweed was insufficient and his Department will be assessing the problem in more detail, prior to the construction of a new sewage treatment works to replace the current one at Bellozanne. 

Senator Sarah Ferguson said: “The Minister has put great reliance on a report, the results of which were taken on one day, with no allowance for seasonality. These results were not done over an extended period. From a scientific view the report is severely flawed.”

The Infrastructure Minister agreed, saying: “I take advice from a whole raft of experts and in this case the Senator is right, the testing was done on a particular day and because of that I have asked for the testing to be re-done over the next couple of months by my Department.”   

Senator Ferguson then asked: “Has the department exceeded its discharge limits for nitrogen from the Bellozanne sewage treatment plant in St Aubin’s Bay and if so by how much and for how long?”

The Infrastructure Minister replied: “The Department has exceeded its total nitrogen limits from the sewage treatment works and has done so since the limit was first introduced in the late 1990s.

“On average it is four times higher than the limit of 10mg of nitrates per litre that was imposed by the regulator, however it can be over six times higher at certain periods. This stringent standard was introduced in the 1990s and was based on compliance with the European Waste Water Treatment Directive. We have not met those limits, but the mains water coming out the tap is 40-50mg of nitrates per litre, so you are not going to get it coming out of the treatment works any lower.”   

Deputy Ferguson added: “Will the proposed new plant be sufficient to deal with this problem and should it be dealt with urgently?"

The Minister replied: “The new plant has been designed for a population based on growth to 118,000 Islanders, plus a further expansion of 20% which takes us up to 140,000. We can’t just base it on those living in the Island but also tourists coming here.”

Deputy Andrew Lewis asked: “There has been much speculation about the contribution this outflow causes to the sea lettuce in St Aubin’s Bay. Can the Minister clarify whether it is a cause of that or not?"   

The Minister said: “Despite recent opinions about the cause it is clear the blooms are not just caused by human-made nitrates going into the harbour as some people believe. Sea lettuce is a naturally occurring algae and its variations change from year to year and place to place. It is strongly influenced by uncontrollable factors such as wind, tide and coastal currents, as well as water temperature and nutrient levels.

“I have seen an article published in New Zealand, which underlines that it is not just appearing in St Aubin’s Bay, or the French coast. It is a worldwide problem.

“I don’t believe that the outflow from the sewage treatment works, or the streams going into St Aubin’s Bay, are the sole cause of the blooms that we have had over the last few summers. They certainly add to the problem but they are not the cause.

“We have a report commissioned by the Environment Department which clearly showed nitrate levels continued to rise as you head towards St Malo Bay. Some 80% plus of nitrates in St Aubin’s Bay come in offshore from Jersey."

But Deputy Montford Tadier said local environmentalists had produced reports claiming Bellozanne was a major cause of the seaweed infestation.  

Deputy Tadier said: “Save our Shoreline (SOS) are at odds with the Minister as the green algae is there almost like a tree coming out of the outflow. I think that is a moot point. I think the Minister would agree with me that you should treat the cause, not just the symptoms and with that in mind I know he supports user pays in Jersey, but does he also support polluter pays in this instance?"

The Minister replied: "I encourage Deputy Tadier to re-look at those images produced by SOS because his interpretation is certainly not the same as mine. But I do agree with him that we do need to look at the cause and the cause for high nitrate levels in our water is because it is in our water, not because it is in our sewage treatment plant. When you have got water coming out of your tap which has 40-50mgs per litre of nitrate in it, it is not surprising that the water coming from the plant will have a similar level of nitrates.

“We are working with Jersey Water and the farming community to reduce nitrate levels and there has been some significant improvement in recent years.”