Water quality tests on tanks near Belco found trace levels of pollution – but at levels well within international standards for drinking water.

Geoff Smith, an environmental engineer with the Department of Environment and Natural Resources, and Shaun Lavis, hydrogeologist with the DENR’s pollution control section, wrote in the Envirotalk newsletter that water samples were taken from homes near Belco in response to recent complaints.

While the samples did contain nickel and vanadium – elements which are linked to the heavy fuel oil used by Belco – the levels were within international standards.

The tests also discovered dioxins and furans – pollutants created by combustion engines – in water tank sediment.

But Dr Smith and Dr Lavis found that the sediment found in tanks near Belco was similar to that found in samples taken from elsewhere on the island.

Their report said: “This indicates that Belco emissions are not the primary source of dioxins and furans in the sediments that collected in water tanks close to Belco.”

The report said the “fingerprint” of the pollutants found in the tanks were similar to that produced by vehicle exhaust.

The report said: “This suggests that soot particles from road vehicles in Bermuda are the predominant source of dioxins and furans in the sediments of water tanks collected for this study.”

Questions about water quality arose last year after Belco began to operate its North Power Station in February 2020.

Pembroke residents complained about the smell of exhaust, pillars of smoke coming from the towers and soot on their roofs.

Further complaints arose in June 2020 after soot was dispersed in Berkeley Hill when an engine was restarted after a shutdown for servicing.

One householder highlighted that debris was left on roofs and in yards while Jason Hayward, the Minister of Labour and MP for Pembroke Central, said he was worried about increased emissions “spewing” from the power plant, which had left oily deposits on houses and cars in the surrounding area.

The report in the Envirotalk newsletter said samples of both water and sediment were taken from several homes north and northeast of Belco’s Pembroke plant, where most of the complaints had come from.

Control samples were also taken from the Marine and Ports Mooring Buildings in Paget and the Shorelands Building in Flatts.

The samples were then sent to Bureau Veritas Laboratories in Bedford, Nova Scotia which compared samples to international drinking water standards.

The results found that combustion-related pollutants measured in the tanks were well below international drinking water standards.

The report said: “Nickel was detected in only one of the ten water tanks sampled – the Old Berkeley School – and at 0.0027 milligrams per litre, it was over seven times lower than the most stringent drinking water limit.

“Vanadium was also measured in tank water sampled around Belco at concentrations below the standards.”

The only parameters failed in the tests were coliform and E. coli bacteria in some tanks which was likely caused by bird and lizard faeces on roofs.

Bacteria in water tanks can be treated through periodic chlorination or filtration technology.

Combustion-related pollutants were also found in sediment samples, including dioxins and furans which generally do not dissolve in water.

The report said: “The dioxin and furan fingerprint of the water tank sediments closely resemble the total exhaust and particulate emissions that have been measured from the tailpipes of gasoline and diesel road-vehicles.”

While the sediment could be dangerous if mixed into the water, the report said suspended particles would be “readily apparent” at levels high enough cause problems.

The report said: “It is likely that someone encountering such concentrations would reject the water on the basis of its appearance.

“To DENR’s knowledge, this is a very rare occurrence, which suggests that the risk of mixing sediment in the tank water to the levels described above is unlikely.”

However the report said the DENR would launch an investigation into what factors could lead to sediment being suspended in the water, and if the potential of such mixing should dictate a change in water standards.