Booms are still sitting on the Grand Canal near Blackhorse Bridge, in Inchicore.
The Electricity Supply Board’s (ESB’s) environmental contractors have been regularly taking water samples from the canal there, and a nearby drain, show records released under Access to Information on the Environment (AIE) regulations.
Results for samples taken in May 2021 and January 2022 – those taken from the open drain, rather than the canal – show pollution associated with oil products, says John Wenger, a professor of physical chemistry at University College Cork (UCC).
More precisely, they “showed the presence of numerous organic compounds that are typically found in petroleum-based products, which include many types of oil”, says Wenger.
One sample taken after reports of pollution in May 2021, Wenger said, “showed the presence of a range of polycyclic aromatic hydrocarbons (PAHs), which are highly toxic”.
Total PAH concentration, he said, was approximately 1,000 times the allowable concentration in drinking water.
Wenger says the concentration of one type of hydrocarbon was within limits in the May 2021 sample. But that the concentration of aromatic hydrocarbons, which are from a family of toxic chemicals, is worrying.
It far exceeds the accepted values of the chemical as set by the United States’s Environmental Protection Agency, endorsed by the World Health Organisation (WHO), he said.
Flagging Leaks
Workers at Waterways Ireland emailed the ESB staff on 28 May 2021 to flag a leak, shows correspondence between the two bodies released under the AIE regulations.
“We have just had a report of a suspected oil leak possibly emanating from the ESB cables between 3rd and 4th lock Grand Canal,” says the email.
ESB high-voltage cables use fluids as an insulating medium, and the leaking fluid is usually a mix of mineral oil and linear alkylbenzene (LAB).
“We’ll get Network Technicians out to site immediately,” an ESB worker emails back.
An ESB spokesperson said that, while Waterways Ireland flagged the May leak, the ESB isn’t reliant on them to do that.
It constantly monitors the cables, the spokesperson said. “And any drop in pressure that may indicate a leak sets off an alarm that is detected by our 24/7 control centre.”
They didn’t say why ESB didn’t get any alert around the May leak.
But in an email from 11 June 2021, an ESB staff member suggests that any of the leaked LAB and mineral oil shown in the drain samples that it had gotten back could have been third-party pollution or a historic leak that had already been repaired.
It’s unclear if pollution from the open drain near the canal is polluting, or had polluted, the Grand Canal.
A spokesperson for the ESB declined to say: “We have nothing further to add to the statements that have been provided at this stage.”
Last month, locals in Inchicore had said they’d noticed the water looking cloudy. The water still looked blurry near the boom placed on the northern banks of the Grand Canal in January.
Another leak had happened in the final days of 2021, but that was from another source. It came from a small boarded-up site “approximately 25m northwest of the 3rd Lock and Blackhorse Bridge,” says an email from ESB staff to Waterways Ireland.
Contractors were excavating and hit an underground cable that runs from Inchicore to Francis Street.
“The cable fluid leached into the ground from the damaged cable and then found its way to the canal exiting through the stone works (Wall) of the lock gate,” says the email.
The email listed measures that ESB’s environmental contractors, Enva, were taking to tackle oil pollution, including absorbent booms and floating barriers to suck pollution out of the water, and to stop it flowing into the Camac River.
A spokesperson for ESB said that the presence of hydrocarbons in the sample taken after this December 2021 leak fits with the presence of LAB.
“LAB is readily biodegradable in this environment and due to the low solubility of LAB in water, it is considered highly unlikely to be ecotoxic,” they said. Some of the pollution shown in the lab reports could come from other sources, said the spokesperson.
The EPA report from 2020 says that cable-fluid “must be considered hazardous”, because mineral oil is classified as hazardous, even while LAB isn’t.
A Longer-Term Plan?
Emails mention that booms have been in place near the canal for years, raising questions about whether there has been ongoing pollution of waters around there.
“Enva replaced all Booms that were in place along the canal prior to this spill taking place,” says in an email on 20 December 2021, after the leak caused by the excavating contractors.
Another email from 31 May 2021 says the booms have been in place “at this location” since 2019.
An ESB spokesperson said those booms were in place on the drain north of the canal as a precautionary measure, but gave no further details.
On 12 February this year, orange and white booms still sat on the north bank of the Grand Canal in Inchicore and stretched across the canal just east of the Black Horse Bridge.
A spokesperson for ESB didn’t say if it had ongoing cable issues in the area, but said there was no connection between the May and December leaks last year.
ESB has been monitoring the water in the Grand Canal, and a nearby drain, at Blackhorse Bridge at the southern end of Inchicore for months, show the emails and sample reports.
An email from an ESB consultant contaminated land specialist to colleagues in September 2021 mentions how ESB was also working with consultants to assess sites where there have been historic fluid leaks from cables.
“Some of these sites are located along the northern bank of the Grand Canal west of Blackhorse Bridge,” the email says.
The ESB spokesperson said that ESB plans to replace the cables, “on the north of the Grand Canal, between Blackhorse Bridge and our Inchicore substation” within the next 12 months.
“During this time, we continue to work closely with the relevant authorities including Waterways Ireland and Dublin City Council,” the spokesperson said.
It’s not the only cable needing to be replaced, the emails show.
“In Dublin there are 5 underground 220kV cables dating from 1971 that are reaching end of life which now require replacement,” says an email dated 16 August 2021 from the ESB to Waterways Ireland.
Between 1 January to 31 December 31, ESB recorded cable leaks on eight circuits in County Dublin, show its records.