http://au.news.yahoo.com/thewest/a/-/newshome/15001651/gloom-over-anaemic-rivers/

Gloom over 'anaemic' rivers

Authorities have all but abandoned improving the health of big areas of the Swan and Canning rivers in the short term, according to a report that shows the system's condition is anaemic.

The Swan River Trust's annual report painted a bleak picture of the waterway after a year in which it was hit with mass fish kills and several toxic algal blooms.

According to the trust's own monitoring, nitrogen levels were too high at almost half of its stations for the fourth year in a row, while phosphorous levels exceeded benchmarks at 20 per cent of sites.

The report showed the amount of chlorophyll-a - a green pigment that indicates algal growth - was far too high everywhere and had been getting worse since 2008.

And dissolved oxygen levels, which were propped up by oxygen plants as a "last line of defence", were too low in each river area except its lower reaches, which were most affected by seawater.

Crucially, the trust said conditions were not expected to improve in many areas and according to several criteria "in the foreseeable future".

This was because of the system's high embedded nutrient level and Perth's lack of winter rain, which reduced the rivers' ability to flush themselves out.

The trust reported six sewage discharges into the rivers last year, 11 industrial discharges and 22 oil slicks or spills.

A spokeswoman for Environment Minister Bill Marmion said the trust had failed to meet its own benchmarks.

"The trust and its partners deliver many positive initiatives that improve water quality and environmental condition in priority catchment areas," she said.

Greens MP Alison Xamon said the trust's report revealed a grim picture of the health of the rivers and legislative action was urgently needed to clean the system.

Shadow environment minister Sally Talbot said the rivers would not recover until water-soluble fertilisers were banned in the catchment."

Comment

Ms Talbot has missed the point, all fertilizers HAVE to be water soluble. 

All living organisms (bacteria to humans) are about 70% water and can only consume water soluble material. Therefore fertilizer, food and sewage is always water soluble. 

The headline hits the mark, perhaps unintentionally. 
The problem with polluted rivers and lakes is lack of IRON and not excess nutrients. 

Nualgi provides iron on a silica base.