At a 18 April meeting of the board, chairman Lemuel Hurlston reported that in June 2011, the Water Authority granted a licence to CUC to discharge cooling water from several wells at its property into the North Sound.
The cooling water is used to cool the engines of CUC’s generators.
Under the terms of the permit granted from the Water Authority, CUC is permitted to discharge 12.7 million gallons per day of cooling water into the sound, at a maximum temperature of 107.6 degrees Fahrenheit.
“In December 2011, CUC notified the authority that low level of petroleum hydrocarbons had been detected in the discharge,” the meeting minutes noted.
Petroleum hydrocarbons are chemical compounds from crude oil.
The Water Authority asked CUC to review the matter further and, the week before Easter this year, CUC provided testing results of water from the six wells that cool its generators.
“These results confirmed the presence of low level petroleum hydrocarbons in four of the six supply wells that had been tested. CUC, the Department of Environment and the authority met on 17 April, 2012, to discuss and review the results.
“The three parties agreed that although the levels of petroleum hydrocarbons were low, there is reason for concern,” the minutes read.
The document continued: “At this stage, however, it is not clear where these contaminants come from and it was agreed to continue with further testing and to review historical information on spills at CUC and other industrial activities within the vicinity of CUC.”
Further results will be available and reviewed at a meeting scheduled for the middle of this month.
In a statement to the Caymanian Compass Monday afternoon, CUC said it was aware that samples of cooling water discharged into the North Sound and in the ground water around CUC had results that indicated the “possible trace presence of hydrocarbons”.
The statement read: “Upon identification of these results, CUC reported this information to the Water Authority. CUC’s latest test results conducted within the last two months reported that there was no trace presence of hydrocarbons in the discharge into the North Sound.
“CUC’s abstraction and discharge licences require CUC to report any contamination of hydrocarbons or toxins to the Water Authority. Although the values listed in these results are detectable by the test, all tests are below the minimum quantifiable limits of the tests. The minimum quantifiable limits of the recent tests results are 3.9 parts per million.”
The CUC statement continued: “After discussions with the independent laboratory that conducted the tests and both Water Authority and Department Of Environment, it is possible that these results are false positive results based on the very low level of results and being below the minimum quantifiable limits of the test.
“Based on this information and ongoing discussions with the Water Authority and DOE, there has been no information that would confirm the presence of hydrocarbon above the minimum quantifiable levels to determine any negative environmental impact. However, CUC continues to monitor this issue and will continue to discuss the results of the testing with the relevant government authorities to ensure the ongoing protection of our environment.”
The discharge permit granted to CUC from the Water Authority stipulates that “no chemical, toxic or harmful substances” be added to the water that is discharged into the Sound.
“Among the testing carried out by CUC is the test for Total Recoverable Petroleum Hydrocarbons, Method EPA 1664. It should be noted that for some of the samples the lab reported results that are above the analytical method detection limit of 1.3 parts per million but below the practical quantitation limit of 3.9 parts per million, this means that the sample had a positive result, but it cannot be quantified.
“The lab has also confirmed that it is possible to have false positives if the results fall in the range between the analytical detection method limit and the practical quantitation limit. Interpretation of these positive results has to done with caution,” said Hendrik-Jan van Genderen, water resources engineer at the Water Authority.
Mr. van Genderen said that because some of the results for individual feed water sources were positive for petroleum hydrocarbons while the discharged water from the same unit had a non positive result, the Water Authority could “not conclude with certainty that CUC is discharging hydrocarbons into the Sound”.
“A review of the history of the site and other industrial activities in area has been carried out to identify possible sources of contamination,” Mr. van Genderen added.