The National Roads Authority illegally discharged well waste at four roadside locations in Grand Cayman for a period of roughly eight years.
A report from Water Authority Cayman sheds new light on how this practice came to be, and the various contaminants revealed by testing at the Water Authority’s own laboratory, as well as in laboratories overseas.
For roughly eight years, the NRA discharged waste collected by its fleet of vacuum trucks at four sites across Grand Cayman, including the wetlands area along the Linford Pierson Highway.
“When you have heavy rainfall it picks up anything from the surface that is there, dust, debris, you name it, and it flushes it into the wells,” said Water Resources Engineer Hendrick van Genderen. “There can be anything.”
That includes known carcinogens arsenic and benzo(a)pyrene.
Mr. van Genderen told Cayman 27 the Water Authority’s report includes analysis of sludge and water samples taken from the Linford Pierson disposal site, a drainage well on Seymour Road, and a wetlands control site in July.
“We found a number of metals in the samples, but you’re going to work your way back to: is this really caused by the sludge that is disposed there, or is it from somewhere else, and in many instances, we find metals, and then we find the same level of metals in your control sample,” said Mr. van Genderen.
The report concluded that the waste mainly consists of water and inert materials, and is mainly inorganic. The metals detected in water sampling, including iron and aluminum which exceeded Florida standards, cannot be directly linked to well-cleaning materials.
Mr. van Genderen said there is, however, an explanation for the high levels of arsenic in sludge samples.
“If you only instinctively look at the waste in the wells and find high arsenic levels, ooh, everybody’s like what is this, what is going on here? But we knew from our previous work that we did that, that arsenic is in our environment anyway at elevated levels than what is deemed safe in Florida,” said Mr. van Genderen.
As for the benzo(a)pyrene (which can be present in char-grilled and smoked meats, according to the Hong Kong Centre for Food Safety), the report said there was insufficient data to confirm it and other semi-volatile organics in sludge samples were directly linked to well cleaning waste.
The report said it’s likely the semi-volatile organics originated from traffic emissions deposited on the surface and flushed into the wells during rainfall events.
The NRA suspended its well vacuuming programme after Cayman 27’s investigation revealed the illegal discharge in June.
In September, the NRA struck a deal with the Department of Environmental Health to resume the programme, disposing of the well waste at the George Town landfill on a temporary basis. That arrangement became permanent later that same month.