The possibility that residents in the vicinity of two illegal landfills sealed off last week might have been exposed to toxic fumes could not be excluded, according to two environmental experts.

Two quarries in the limits of Siġġiewi and Iklin which were being used a dumping site for skips laden with unseparated and potentially hazardous waste, were sealed off as part of a planning authority crackdown on illegal landfills.

The untreated waste, which included electronic material, plastics and sprayed wooden furniture was being set on fire and subsequently covered in debris, in similar fashion to the old Magħtab landfill which was closed down 10 years ago.

The introduction of strict EU directives prohibited such practices due to possible toxic emissions and the contamination of the water table.

Probed by The Sunday Times of Malta on the possible negative environmental impact to surrounding communities, Prof. Edward Mallia said that once mixed waste had been haphazardly set on fire, some kind of toxic emissions could not be ruled out.

One of these could be dioxin – a chemical compound also known as persistent organic pollutant which is normally a by-product of the combustion of municipal waste as well as fuels like wood, coal, and oil.

Prof. Mallia said even though some dioxins were not toxic, exposure to such fumes on the assumption that they posed no risks would be “insane”.

Dr Alan Deidun, a marine biologist warned that combustion of untreated waste could be a source of volatile organic compounds, which may be toxic and even cancerogenous.

He said the only safe way to burn mixed waste was through the use of highly sophisticated incinerators which operated at very high temperatures. “Dioxins are so toxic even a concentration in the order of parts per billion, would pose certain risks if it disperses in the atmosphere,” Dr Deidun said.

In this context it would be presumptuous to rule out any possible health hazards, not only in Iklin but also in other parts of the island, he said. Regarding the possibility of contamination to the water table, both environmentalists pointed out that the porous nature of the Maltese sedimentary rocks coupled with proximity of the quarry’s base to the water table, would pose additional risks.

“This is why there is a strict regulatory regime on the operation of landfills,” Prof. Mallia remarked.