To cap or not to cap

Dr Christopher Ciantar (The Sunday Times, August 15) assures us that the waste dump at Maghtab is being rehabilitated by WasteServ Malta Ltd on behalf of Government.

In a nutshell WasteServ's approach towards rehabilitating the landfill involves shifting around huge sections of the mound so that the desired shape is attained.

Also, that a central gas extraction unit shall be installed to recover any gas which comes out of the 400-odd perforated pipes planned to be installed vertically downwards into the waste mound.

Finally, the issuing waste gases shall be collected and subsequently flared. The reader is also informed that WasteServ's rehabilitation of Maghtab follows an investigative study of the site to develop environmentally sound strategies for its rehabilitation.

This is all fine, but what exactly did these investigations reveal? What are the likely consequences on the surrounding area and n residents of Maghtab, Gharghur and Madliena, among others? In the absence of more information I am inclined to believe that the livelihood and health of people may be at stake here and such actions demand that a Health Impact Assessment should have been carried out and the outcome made public knowledge before starting any work.

There is another issue of great concern. The Maghtab area has a high concentration of livestock farms which for years have been battling to eradicate disease caused by invading vermin such as rats from their farm premises. The Food and Veterinary Division of the Ministry of Agriculture and Fisheries surely must be aware of this.

While on the subject, could WasteServ also explain why the 'old' Maghtab landfill will be rehabilitated without capping?

I trust that WasteServ is well acquainted with the relevant EU regulations. The Landfill Directive 1999/31/EC sets out the regulatory requirements that apply to all member states. One of these requires that landfills in general must have a combination of a geological barrier and a top liner installed during their post-closure phase. Of course, a geological barrier for Maghtab is now out of the question, but a capping liner can and must be installed.

The bone of contention is that up to now the Maghtab area has always been considered to be outside the boundary limits of the Aquifer Zone (or Nitrate Vulnerable Zone as dubbed by the Water Services Corporation). However other, equally trustworthy sources insist that it may not be the case. In fact, thanks to computerised hydrological models, one can scientifically establish an aquifer boundary or ground water flow with reasonable accuracy.

The bare fact is that we simply do not know whether the mean sea-level aquifer extends right underneath Maghtab or even if the Maghtab's catchment's water percolates inland into the main aquifer.

I look forward to the day when a bona fide WSC official comes forward and officially assures us that there is no leachate danger from the Maghtab landfill and that our main source of potable water is safe; is that's too much to ask?

One thing we're sure about; borehole tests for nitrates in the area and others, up to a kilometre radius, revealed an outrageously high nitrate content. Is this solely due to agricultural activity in the area or also to a leachate influx from the waste dump that has found its way unchecked into the sea-level aquifer? At any rate don't panic, we still have our reverse osmosis plants...