No plans to study 'radioactive' ash at Bengħisa quarry
Leaching of toxic waste would persist
The planning authority is not exploring any plans to study the Bengħisa quarry, limits of Birżebbuġa, which is filled with fly ash found to be radioactive by University researchers, a spokesman has confirmed.
The ash was produced when the Marsa power station was still coal-fired and scientific tests - conducted by lecturers Josette Camilleri and Franco Montesin from the University's Architecture and Civil Engineering Faculty and Michael Sammut from the hospital's Pathology Department - had found it contained high levels of radioactivity.
"The Malta Environment and Planning Authority did not conduct studies on the Bengħisa fly ash and so does not have any results. Interventions or the rehabilitation of this site will only be considered once a holistic plan and all the necessary studies are undertaken," the spokesman said, insisting no such plan was being explored at the time being.
The mound of fly ash is situated at the back of the Freeport on the south eastern cliff face that borders the Ħal Far industrial estate. Winds and rain occasionally spill the ash, which was covered with soil, off the cliff edge and into the sea below.
The pulverised fuel ash had "very high levels of all the radionuclides (radioactive contaminants) under test, namely K40, PB212 and PB214", the research found. The three elements are derivatives of potassium and lead.
Speaking to The Times, Dr Camilleri had expressed surprise by the reaction when the newspaper revealed that fly ash from the power stations was dumped in a quarry.
"Everybody seems to have forgotten that radioactive fly ash produced when coal was burned at Marsa was dumped in a disused quarry at Bengħisa," Dr Camilleri had pointed out.
Coal was last used at the Marsa power station in 1995, when it was modified to run on heavy fuel oil. This also produces fly ash which, though not radioactive, contains traces of hazardous heavy metals.
The 2005 research, which also studied the use of fuel ash as a replacement for cement and aggregate in concrete mixes, established it was safer to use the fly ash produced from coal burning in concrete mixes rather than dump it.
The study showed that replacing between 10 and 20 per cent of cement in concrete mixes with fly ash produced radioactive levels that were lower than that of limestone from which stone is derived. The resulting concrete was of good quality.
"The health risk of such modified concrete should not be substantially different from the utilisation of limestone, which is the main building material in Malta," the researchers said.
They said land filling of fly ash was problematic because leaching of toxic waste substances took a long time to form and would persist for hundreds of years.
In 1991, the Marsa power station used 250,000 tonnes of coal, producing about 50,000 tonnes of pulverised fuel ash.