No health risks from fireworks chemicals in tap water – WSC

Traces of a chemical released into the environment by fireworks were detected in tap water but well below limits recommended by the World Health Organisation, the Water Service Corporation said.

Tests carried out by the WSC in 2017 found traces of perchlorate that were 50 times lower than the recommended limit imposed by WHO in samples taken from ground water, and even lower in tap water.

These amounts do not pose any health risks to the public, the WSC said.

The corporation released this information in response to a report published in MaltaToday that referred to a study by university rector Alfred Vella and chemist Colette Pace, which attributed the presence of perchlorate in water to exposure to fireworks.

Studies by the WSC’s laboratory largely tally with the results found in the study published by Vella and Pace, which was based on samples taken in 2012 and 2013.

The WSC’s tests shows that 46% of ground water sources, reported “trace readings” of perchlorate with an average concentration of 1.4 µg/L and a maximum of 2.7 µg/L.

In the study by Vella and Pace perchlorate was detected in 44% of ground water sources with an average concentration of 1.09 μg/L.

The mean concentration in tap water in the WSC tests amounted to 0.7 µg/L.  The Vella/Pace study showed mean concentrations ranging from 0.4 to 1.6 μg/L. 

While the World Health Organisation recommends a level of 70 µg/L, the US state of Massachusetts recommends a 2 μg/L limit, while California has promulgated a standard of 6 μg/L.

Other states in the US have set public health goals limiting perchlorate to between 1 μg/L to  14μg/L. 

But even if one had to resort to the most stringent limits in the US, “Malta’s tap water would still be 100% safe for consumption”, a spokesperson for the WSC told MaltaToday.

“Moreover, these negligible amounts will be further reduced through the multimillion euro EU-funded upgrades that are being implemented by the corporation,” he added.

The upgrade will decrease the amount of ground water (which is the most likely source of perchlorate in tap water) in the supply to 30% from 40%.

“Therefore, not only is there no cause of alarm but the situation is expected to further improve,” the WSC said.

Researcher Colette Pace, who referred to the more stringent limits applicable in US states, had not attributed any ill effects resulting from drinking tap water alone, butwarned that “when all sources are taken into consideration (food, water and exposure to dust – inhaled and ingested), the amount of perchlorate ingested will be higher than the minimum exposure limit which causes adverse affects in children”.

Perchlorate can interfere with the human body’s ability to absorb iodine into the thyroid gland, which is a critical element in the production of thyroid hormones. 

In adults, thyroid plays an important role in metabolism, making and storing hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. In foetuses and infants, thyroid hormones are critical for normal growth and development of the central nervous system.

The WSC carries out daily tests on water samples

How the WSC tests water quality
Potable water is tested locally at the laboratory within the head office of Water Services Corporation in Luqa, where a team of scientists and lab technicians, carry out daily analysis to achieve the necessary requirements. The laboratory is covered by ISO 17025 accreditation, and is one of the biggest laboratories in the Maltese islands, with over 40 accredited tests, in various water matrices, ranging from drinking water to waste water.

The laboratory employs a team of six scientists, 10 technicians, three samplers and five support staff. On a daily basis they ensure that several samples are collected and analysed from various sources such as reservoirs, pumping stations, village points and also reverse osmosis plants.