[WATCH] Malta has second highest rate of bladder cancer linked to tap water

Water Services Corporation CEO Richard Bilocca on tap water linked to bladder cancer

Malta has the second highest highest percentage of bladder cancer cases attributable to exposure to trihalomethanes (THM) – a chemical linked to bladder cancer, in tap water.

The international study reports that the highest percentage of bladder cancer cases attributable to THM exposure were in Cyprus (23%), Malta (17%), Ireland (17%), Spain (11%) and Greece (10%).

Trihalomethanes are a group of chemicals formed, along with other disinfection by-products, when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter.

The study estimates that 6,561 bladder cancer cases per year are attributable to THM exposure in the European Union.

In reply to MaltaToday’s questions the Water Services Corporation issued a statement stating that Malta is in full compliance of the EU Drinking Water Directive, which ensures that all the water that reaches clients in Malta and within the EU is safe for human consumption.

The limit featured for THM in the Drinking Water Directive is 100 µg/litre. This limit was never exceeded in Malta and the average reading is of 49.4 µg/litre which is half the maximum allowed.

The average reading of THM exposures ranges from just 0.02 µg/litre in Denmark to 66.2 µg/litre in Cyprus.

“This is also confirmed in the quoted scientific paper, therefore there is no reason for alarm.”

The paper itself refers to a ‘casual association between bladder cancer and THM exposure’.

The Water Services Corporation insists that there is “no known direct correlation between bladder cancer and potable water” but the corporation is also currently investing heavily in improving the water well beyond EU established limits.

“This will not only result in a remarkable improvement in taste but will also result in a further reduction in THM levels.”

In order to obtain this data, the researchers asked municipal water quality assurance staff to fill out questionnaires that asked for the concentrations of both total and individual THMs in water samples collected from the tap, as well as within the distribution pipes and at the plants where the water was treated.

The findings showed a lot of differences between the THM levels from country to country. In all EU countries, the level in drinking water was, thankfully, well below the permissible EU limit of 100 μg/L, at an average of 11.7 μg/L.

The researchers finally investigated how the average THM level was associated with the incidence of bladder cancer in each country, using the international bladder cancer database. This enabled them to estimate the number of cases that could be ascribed to THM exposure.

As a result, they found that about 6,500 bladder cancer cases each year could be said to be due to THM exposure.

The lowest attributable risk was in Denmark, at 0%, while the Netherlands, Germany, Austria and Lithuania.

The researchers claim that the current levels in certain countries could still lead to considerable bladder cancer burden, which could be prevented by optimising water treatment, disinfection and distribution practices and other measures.”

“The best way to reduce these levels is to begin with the 13 countries in which the average levels are highest. Once these come down to the EU average of 11 μg/L, the estimated number of bladder cancers due to this reason could be reduced by 44%. This study thus shows the burden of bladder cancer attributable to THM exposure in tap water and suggests ways to control it”.